Through electrode substrate, mounting substrate, and method for producing through electrode substrate

Abstract

A through electrode (20) includes: a closing electrode (21) that closes a through hole at a narrowest portion (163); a first filling electrode (27); and a second filling electrode (28). The closing electrode includes: a closing portion (23) located at the narrowest portion; a first portion (24) extending along the wall surface from the closing portion to a first surface (13); and a second portion (25) extending along the wall surface from the closing portion to a second surface (14). The first filling electrode is located inside the first portion and is located between the closing portion and the first surface in the thickness direction of a substrate. The second filling electrode is located inside the second portion and is located between the closing portion and the second surface in the thickness direction.　The closing electrode includes a plurality of first crystal grains, and the first filling electrode and the second filling electrode each include a plurality of second crystal grains having a crystal structure different from that of the first crystal grains.　Furthermore, the closing portion of the closing electrode has a first elastic modulus, and the first filling electrode and the second filling electrode each have an elastic modulus smaller than the first elastic modulus.

Description

Through-electrode substrate, mounting substrate, and method for manufacturing through-electrode substrate

[0001] TECHNICAL FIELD Embodiments of the present disclosure relate to a through electrode substrate, a mounting substrate, and a method for manufacturing a through electrode substrate.

[0002] Through-hole electrode substrates are used in a variety of applications. A through-hole electrode substrate is a component including a substrate having a first surface and a second surface, through holes formed in the substrate, and through electrodes located in the through holes. A through-hole electrode substrate is used, for example, as an interposer. An interposer is a component interposed between two electrical components. For example, a through-hole electrode substrate is interposed between two LSI chips in the thickness direction. A through-hole electrode substrate may also be interposed between an element such as an LSI chip and a mounting substrate such as a motherboard. A through-hole electrode substrate is also used as a component constituting passive components such as an inductor or a capacitor.

[0003] For example, as disclosed in Patent Document 1, the through electrodes of the through electrode substrate have various structures. A first example of the through electrode is an example in which the entire through hole is filled with a conductive material such as copper. A second example is an example in which a layer of a conductive material such as copper is formed on the wall surface of the through hole. A third example is an example in which a layer of a conductive material such as copper is formed on the wall surface of the through hole, and a layer of a conductive material that closes the through hole is formed along the first surface or the second surface of the substrate. In the second and third examples, a resin material is filled in the space of the through hole where no conductive material is present.

[0004] International Publication No. 2022 / 173057

[0005] There is a demand for increasing the maximum value of the current that can be passed through the through electrode (hereinafter also referred to as the allowable current). In order to increase the allowable current, it is preferable that the entire through hole be filled with a conductive material such as copper, as in the through electrode of the first example.

[0006] In the through electrode of the first example, the larger the dimension of the through hole in the surface direction, the higher the allowable current of the through electrode. However, the larger the dimension of the through hole, the more likely defects such as voids are to occur in the conductive material filled in the through hole.

[0007] An object of the embodiments of the present disclosure is to provide a through hole electrode substrate and a method for manufacturing a through hole electrode substrate that can effectively solve such problems.

[0008] Embodiments of the present disclosure relate to the following [1] to

[23] . [1] A through electrode substrate, comprising: a substrate including a first surface, a second surface located opposite to the first surface, and a through hole penetrating from the first surface to the second surface; and a through electrode located in the through hole, wherein the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a minimum portion located between the first end and the second end, wherein the through hole has a minimum dimension at the minimum portion that is the minimum value of the dimension of the through hole in a plane direction of the first surface, and the through electrode includes a closing electrode that closes the through hole at the minimum portion, a first filling electrode, and a second filling electrode, wherein the closing electrode includes a closing portion located at the minimum portion, a first portion extending along the wall surface from the closing portion to the first surface, and a second portion extending along the wall surface from the closing portion to the second surface, and the first filling electrode is located inside the first portion and between the closing portion and the first surface in a thickness direction of the substrate, A through-hole electrode substrate, wherein the second filling electrode is located inside the second portion and between the closed portion and the second surface in the thickness direction, the closed electrode includes a plurality of first crystal grains, and the first filling electrode and the second filling electrode each include a plurality of second crystal grains having a crystal structure different from that of the first crystal grains.

[0009] [2] In the through electrode substrate described in [1], the plurality of second crystal grains of the first filling electrode and the plurality of second crystal grains of the second filling electrode may each include at least one linear crystal grain, and the linear crystal grain may have a crystal boundary including a pair of linear grain boundaries that are in contact with the boundary between the closing electrode and the first filling electrode or the boundary between the closing electrode and the second filling electrode and extend parallel to each other.

[0010] [3] In the through electrode substrate according to [1] or [2], the plurality of first crystal grains may have a first average cross-sectional area, and the plurality of second crystal grains may have an average cross-sectional area larger than the first average cross-sectional area.

[0011] [4] In the through hole electrode substrate according to any one of [1] to [3], the plurality of first crystal grains may have a first average crystal grain size of 50 nm or more and less than 500 nm.

[0012] [5] In the through hole electrode substrate according to any one of [1] to [4], the plurality of second crystal grains may have a second average crystal grain size of 500 nm or more and 2.0 μm or less.

[0013] [6] In the through electrode substrate according to any one of [1] to [5], the through electrode may have a first distance that is a maximum value of the distance from the first surface to the closed portion in a thickness direction of the substrate, and a second distance that is a maximum value of the distance from the second surface to the closed portion in a thickness direction of the substrate, and the ratio of the first distance to the thickness of the substrate may be 0.10 or more, and the ratio of the second distance to the thickness of the substrate may be 0.10 or more.

[0014] [7] In the through electrode substrate according to any one of [1] to [6], the closed electrode may include a surface portion located between the closed portion, the first portion, the second portion and the wall surface, and extending along the wall surface from the first surface to the second surface.

[0015] [8] In the through hole electrode substrate according to any one of [1] to [7], the plurality of first crystal grains and the plurality of second crystal grains may both contain the same metal material as a main component.

[0016] [9] In the through hole electrode substrate according to any one of [1] to [8], the ratio of the thickness of the substrate to the minimum dimension may be 2.5 or more and 35.0 or less.

[0017]

[10] In the through hole electrode substrate according to any one of [1] to [9], the ratio of the thickness of the closed portion to the thickness of the substrate may be 0.05 or more and 0.50 or less.

[0018]

[11] The through electrode substrate according to any one of [1] to

[10] may comprise a first conductive layer located on the first surface and connected to the first fill electrode and the first portion of the closing electrode.

[0019]

[12] The through electrode substrate according to

[11] may comprise a second conductive layer located on the second surface and connected to the second filling electrode and the second portion of the closing electrode.

[0020]

[13] The through electrode substrate according to any one of [1] to

[12] may include a first surface resin layer located on the first surface, and the first surface resin layer may overlap the first end of the wall surface in a plan view.

[0021]

[14] The through electrode substrate described in

[13] may include a second surface resin layer located on the second surface, and the second surface resin layer may overlap the second end of the wall surface in a plan view.

[0022]

[15] In the through hole electrode substrate according to any one of [1] to

[14] , the substrate may be a glass substrate.

[0023]

[16] A mounting board comprising: the through electrode substrate according to any one of [1] to

[15] ; and an element electrically connected to the through electrode of the through electrode substrate.

[0024]

[17] A method for manufacturing a through electrode substrate, comprising: a step of preparing a substrate including a first surface, a second surface located opposite to the first surface, and a through hole penetrating from the first surface to the second surface; and a through electrode forming step of forming a through electrode partially in the through hole, wherein the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a minimum portion located between the first end and the second end, and the through hole has a minimum dimension at the minimum portion that is the minimum value of the dimension of the through hole in a plane direction of the first surface, the through electrode forming step comprising: a step of forming a seed layer on the wall surface of the through hole; and a plating step of forming a plating layer on the seed layer, and the plating step comprising: a closing plating step of forming a closing electrode that closes the through hole at the minimum portion, and a filling plating step of forming a first filling electrode and a second filling electrode, A method for manufacturing a through-hole electrode substrate, wherein the closed electrode includes a closed portion located at the smallest portion, a first portion extending along the wall surface from the closed portion to the first surface, and a second portion extending along the wall surface from the closed portion to the second surface, the first filling electrode is located inside the first portion and is located between the closed portion and the first surface in the thickness direction of the substrate, the second filling electrode is located inside the second portion and is located between the closed portion and the second surface in the thickness direction, and the concentration of an additive contained in the plating solution used in the filling plating process is higher than the concentration of an additive contained in the plating solution used in the closing plating process.

[0025]

[18] In the method for manufacturing a through electrode substrate described in

[17] , the through electrode may have a first distance that is the maximum value of the distance from the first surface to the closed portion in the thickness direction of the substrate, and a second distance that is the maximum value of the distance from the second surface to the closed portion in the thickness direction of the substrate, and the ratio of the first distance to the thickness of the substrate may be 0.10 or more, and the ratio of the second distance to the thickness of the substrate may be 0.10 or more.

[0026]

[19] In the method for manufacturing a through-hole electrode substrate described in

[17] or

[18] , the closing plating step may include a first plating step of forming a surface portion located between the closing portion, the first portion, and the second portion and the wall surface, and a second plating step of forming the closing portion, the first portion, and the second portion.

[0027]

[20] In the method for manufacturing a through-hole electrode substrate described in

[19] , the concentration of the additive contained in the plating solution used in the second plating step may be higher than the concentration of the additive contained in the plating solution used in the first plating step.

[0028]

[21] In the method for manufacturing a through hole electrode substrate according to any one of

[17] to

[20] , a ratio of a thickness of the substrate to the minimum dimension may be 2.5 or more and 35.0 or less.

[0029]

[22] In the method for manufacturing a through hole electrode substrate according to any one of

[17] to

[21] , a ratio of a thickness of the closed portion to a thickness of the substrate may be 0.05 or more and 0.50 or less.

[0030]

[23] In the method for manufacturing a through hole electrode substrate according to any one of

[17] to

[22] , the substrate may be a glass substrate.

[0031] According to the embodiments of the present disclosure, it is possible to increase the allowable current of the through electrode while suppressing defects such as voids.

[0032] 1 is a cross-sectional view showing a through electrode substrate according to a first embodiment; FIG. 1 is a cross-sectional view showing an example of a through hole in a substrate; FIG. 1 is a cross-sectional view showing an example of a through electrode; FIG. 1 is a cross-sectional view showing an example of dimensions of a through electrode; FIG. 1 is a cross-sectional view showing an enlarged portion of a through electrode; FIG. 1 is a cross-sectional view showing an example of a plurality of first crystal grains and a plurality of second crystal grains; FIG. 1 is a cross-sectional view showing an example of a step of preparing a substrate; FIG. 1 is a cross-sectional view showing an example of a seed layer forming step; FIG. 1 is a cross-sectional view showing an example of a closed plating step; FIG. 1 is a cross-sectional view showing an example of an closed plating step; FIG. 1 is a cross-sectional view showing an example of an filling plating step; FIG. 1 is a cross-sectional view showing an example of a polishing step; FIG. 1 is a cross-sectional view showing an example of a plating step in a first comparative embodiment ... a through electrode substrate according to a second comparative embodiment; FIG. 1 is a cross-sectional view showing a through electrode substrate according to a third comparative embodiment; FIG. 1 is a cross-sectional view showing a modified example of a through electrode substrate; FIG. 1 is a cross-sectional view showing a modified example of a through electrode; FIG. 1 is a cross-sectional view showing an example of dimensions of a through electrode; FIG. 1 is a cross-sectional view showing an example of a first plating step in the closed plating step; FIG. 1 is a cross-sectional view showing an example of a second plating step in the closed plating step; FIG. 1 is a cross-sectional view showing a modified example of a through electrode substrate; 29 is a cross-sectional view showing an example of a closing plating process and a filling plating process. FIG. 30 is a cross-sectional view showing an example of a resist removal process and a seed layer removal process. FIG. 31 is a cross-sectional view showing a modified example of a through electrode substrate. FIG. 32 is a view showing an example of a product on which a through electrode substrate is mounted. FIG. 33 is a view showing a cross-sectional image of a closing electrode and a second filling electrode. FIG. 34 is a view showing a dark field image of the cross-sectional image of FIG. 29. FIG. 35 is a view showing a cross-sectional image of a closing electrode and a second filling electrode. FIG. 36 is a view showing a cross-sectional image of a closing electrode and a second filling electrode. FIG. 37 is a view showing the positions of cross-sectional images of a closing electrode, a first filling electrode, and a second filling electrode. FIG. 38 is a view showing a cross-sectional image of a closing electrode. FIG. 39 is a view showing a cross-sectional image of a second filling electrode. FIG. 39 is a view showing the positions of measurement of the elastic modulus of a closing electrode, a first filling electrode, and a second filling electrode. FIG. 39 is a view showing an indenter used in a nanoindentation test. FIG. 39 is a cross-sectional view showing the indenter being pressed into an object. FIG. 39 is a cross-sectional view showing the object after the indenter has been removed. FIG. 39 is a graph showing the relationship between pressing depth and load.10A and 10B are cross-sectional views showing an example of a plating step in the fourth comparative embodiment;FIG. ...C are cross-sectional views showing a modified example of a through electrode;FIG.

[0033] In this specification, unless otherwise specified, terms meaning base members, such as "substrate," "base material," "plate," "sheet," and "film," are not distinguished from one another solely based on differences in name. For example, the term "substrate" is a concept that includes members that can be called sheets and films.

[0034] In this specification, unless otherwise specified, the term "surface" refers to a surface that coincides with the planar direction of the target plate-like member when the target plate-like member is viewed overall and globally. The term "normal direction" used in relation to a plate-like member refers to the normal direction to the surface of the member.

[0035] In this specification, unless otherwise specified, terms relating to shapes and geometric conditions and values ​​specifying the degree of the shapes and geometric conditions may be interpreted based on the realized function without being bound by strict meaning. Terms relating to shapes and geometric conditions include, for example, "parallel," "orthogonal," etc. Values ​​specifying the degree of the shapes and geometric conditions include, for example, length values, angle values, etc.

[0036] In this specification and drawings, unless otherwise specified, when the positional relationship of a second component with respect to a first component is described using terms such as "above," "below," "upper," "lower," "upward," or "belowward," the second component may or may not be in contact with the first component. In this specification and drawings, unless otherwise specified, when the positional relationship of a second component with respect to a first component is described using terms such as "above," "upper," or "above," the second component may be located "below," "downward," or "below" the first component depending on the usage state of the product.

[0037] In this specification, when multiple upper limit value candidates and multiple lower limit value candidates are listed for a certain parameter, the numerical range of the parameter may be constructed by combining any one upper limit value candidate with any one lower limit value candidate. For example, consider a description that reads, "Parameter B is, for example, A1 or more, or may be A2 or more, or may be A3 or more. Parameter B is, for example, A4 or less, or may be A5 or less, or may be A6 or less." In this case, the numerical range of parameter B may be A1 or more and A4 or less, A1 or more and A5 or less, A1 or more and A6 or less, A2 or more and A4 or less, A2 or more and A5 or less, A2 or more and A6 or less, A3 or more and A4 or less, A3 or more and A5 or less, or A3 or more and A6 or less.

[0038] In this specification and the drawings, unless otherwise specified, the same or similar reference numerals are used to designate the same parts or components having similar functions. The dimensional ratios of the drawings may differ from the actual ratios for the sake of convenience. In this specification and the drawings, some of the components may be omitted from the drawings.

[0039] Unless otherwise specified in the present specification and drawings, one embodiment of the present specification may be combined with other embodiments or modifications to the extent that no contradiction occurs. Other embodiments or modifications may also be combined with each other to the extent that no contradiction occurs.

[0040] In the present specification and drawings, unless otherwise specified, when a plurality of steps are disclosed in a method such as a manufacturing method, other steps that are not disclosed may be performed between the disclosed steps, and the order of the disclosed steps may be changed to the extent that no contradiction occurs.

[0041] The configuration of a through hole electrode substrate and a manufacturing method thereof will be described in detail with reference to the drawings. However, the technical concept of the embodiments of the present disclosure should not be interpreted as being limited to the following specific embodiments.

[0042] The first embodiment is based on and claims priority to Japanese Patent Application No. 2024-107746, filed on July 3, 2024. FIG. 1 is a cross-sectional view showing an example of a through electrode substrate 10 according to the first embodiment. The through electrode substrate 10 includes a substrate 12 and at least one through electrode 20. The substrate 12 includes a first surface 13 and a second surface 14. The second surface 14 is located on the opposite side of the substrate 12 from the first surface 13 in the thickness direction of the substrate 12. The substrate 12 further includes at least one through hole 15 that penetrates from the first surface 13 to the second surface 14. The through electrode 20 is located in the through hole 15. In the example shown in FIG. 1, the substrate 12 includes a plurality of through holes 15. The through electrode substrate 10 includes a through electrode 20 located in each of the plurality of through holes 15.

[0043] (Substrate) The substrate 12 includes an insulating inorganic material. For example, the substrate 12 is 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, or a laminate of these substrates. The substrate 12 may partially include a substrate made of a conductive material, such as an aluminum substrate or a stainless steel substrate.

[0044] An example of the glass used for the substrate 12 is alkali-free glass. The alkali-free glass is glass that does not contain alkali components such as sodium or potassium. The alkali-free glass contains, for example, boric acid instead of an alkali component. The alkali-free glass also contains, for example, an alkaline earth metal oxide such as calcium oxide or barium oxide.

[0045] The thickness T0 of the substrate 12 is, for example, 100 μm or more, or may be 200 μm or more, or 300 μm or more. The thickness T0 of the substrate 12 is, for example, 800 μm or less, or may be 600 μm or less, or may be 400 μm or less.

[0046] The structure of the substrate 12 will be described. Fig. 2 is a cross-sectional view showing the substrate 12. The through electrode 20 is omitted from Fig. 2. The through hole 15 includes a wall surface 16 extending from the first surface 13 to the second surface 14. The wall surface 16 includes a first end 161, a second end 162, and a thinnest portion 163 located between the first end 161 and the second end 162.

[0047] The first end 161 is a portion of the wall surface 16 that is connected to the first surface 13. The through hole 15 has a first dimension R1 at the first end 161 in the surface direction of the first surface 13. The second end 162 is a portion of the wall surface 16 that is connected to the second surface 14. The through hole 15 has a second dimension R2 at the second end 162 in the surface direction of the first surface 13. The through hole 15 has a minimum dimension R3 at a minimum portion 163 in the surface direction of the first surface 13. In other words, the minimum portion 163 is defined as the portion of the wall surface 16 where the dimension of the through hole 15 in the surface direction of the first surface 13 is minimum.

[0048] The first end 161, the second end 162, and the smallest portion 163 may have a circular outline in a plan view. In this case, the first dimension R1, the second dimension R2, and the smallest dimension R3 refer to the diameters of the first end 161, the second end 162, and the smallest portion 163. "Plan view" means viewing the object along the normal direction of the first surface 13.

[0049] The first dimension R1 and the second dimension R2 are, for example, 30 μm or more, or may be 40 μm or more, or 50 μm or more. The first dimension R1 and the second dimension R2 are, for example, 150 μm or less, or may be 120 μm or less, or may be 100 μm or less. The first dimension R1 may be the same as or different from the second dimension R2.

[0050] It is preferable that the difference between the first dimension R1 and the second dimension R2 is small. The ratio R2 / R1 of the second dimension R2 to the first dimension R1 is, for example, 0.80 or more, or may be 0.90 or more, or 0.95 or more. The ratio R2 / R1 is, for example, 1.20 or less, or may be 1.10 or less, or may be 1.05 or less. By reducing the difference between the first dimension R1 and the second dimension R2, it is possible to efficiently increase the allowable current of the through electrode 20 while suppressing defects such as voids.

[0051] The minimum dimension R3 is smaller than the first dimension R1. The dimension of the portion of the through hole 15 located between the first end 161 and the minimum portion 163 may decrease monotonically from the first end 161 to the minimum portion 163. The minimum dimension R3 is smaller than the second dimension R2. The dimension of the portion of the through hole 15 located between the second end 162 and the minimum portion 163 may decrease monotonically from the second end 162 to the minimum portion 163.

[0052] The minimum dimension R3 is, for example, 20 μm or more, and may be 30 μm or more, or 40 μm or more. Because the minimum dimension R3 is 20 μm or more, the allowable current of the through electrode 20 formed in the through hole 15 is sufficiently increased. The minimum dimension R3 is, for example, 120 μm or less, and may be 100 μm or less, or 80 μm or less. Because the minimum dimension R3 is 120 μm or less, a closed portion 23, which will be described later, is easily formed in the thinnest portion 163.

[0053] The ratio R1 / R3 of the first dimension R1 to the minimum dimension R3 is, for example, 1.05 or more, or may be 1.10 or more, or 1.20 or more, or 1.30 or more. The ratio R1 / R3 is, for example, 2.50 or less, or may be 2.00 or less, or may be 1.80 or less, or may be 1.50 or less.

[0054] The ratio R2 / R3 of the second dimension R2 to the minimum dimension R3 is, for example, 1.05 or more, or may be 1.10 or more, or 1.20 or more, or 1.30 or more. The ratio R2 / R3 is, for example, 2.50 or less, or may be 2.00 or less, or may be 1.80 or less, or may be 1.50 or less. The ratio R2 / R3 may be the same as or different from the ratio R1 / R3.

[0055] The minimum dimension R3 may be determined relative to the thickness T0 of the substrate 12. The ratio of the thickness T0 to the minimum dimension R3, T0 / R3, is, for example, 2.5 or more, 5.0 or more, 10.0 or more, or 15.0 or more. The ratio R2 / R3 is, for example, 35.0 or less, 30.0 or less, 25.0 or less, or 20.0 or less.

[0056] 2, the minimum portion 163 may be located midway between the first surface 13 and the second surface 14 in the thickness direction of the substrate 12. In Fig. 2, the symbol K3 represents the distance from the first surface 13 to the minimum portion 163 in the thickness direction of the substrate 12. When the minimum portion 163 is located midway between the first surface 13 and the second surface 14, the ratio of the distance K3 to the thickness T0 of the substrate, K3 / T0, is 0.50.

[0057] Although not shown, the position of the minimum portion 163 in the thickness direction of the substrate 12 may be shifted from the midpoint between the first surface 13 and the second surface 14. That is, the ratio K3 / T0 may be shifted from 0.50. The ratio K3 / T0 may be, for example, 0.40 or more, or 0.45 or more. The ratio K3 / T0 may be, for example, 0.60 or less, or 0.55 or less.

[0058] 3 is a cross-sectional view showing an example of the through electrode 20. The through electrode 20 is located in the through hole 15. The through electrode 20 extends along the thickness direction of the substrate 12 from the first surface 13 to the second surface 14.

[0059] The through electrode 20 includes a conductive material. The through electrode 20 includes at least a closing electrode 21, a first filling electrode 27, and a second filling electrode 28. The closing electrode 21 closes the through hole 15 at the narrowest portion 163. The first filling electrode 27 is located on the first surface 13. The second filling electrode 28 is located on the second surface 14.

[0060] Closing electrode 21, first filling electrode 27, and second filling electrode 28 are plated layers. The plated layers are conductive layers formed by a plating method such as electrolytic plating.

[0061] The through electrode 20 may include a seed layer 201. The seed layer 201 is located between the plating layer and a surface of the substrate 12, such as the first surface 13, the second surface 14, or the wall surface 16. The seed layer 201 is a conductive layer formed by physical film formation such as sputtering.

[0062] The through electrode 20 is mostly formed of a plating layer. The ratio of the volume of the through electrode 20 located inside the through hole 15 to the volume of the space inside the through hole 15 is, for example, 0.80 or more, and may be 0.90 or more.

[0063] The plating layer may contain a metal such as copper, gold, silver, platinum, rhodium, tin, aluminum, nickel, titanium, chromium, or zinc, or an alloy using these metals. The plating layer may contain these metals or alloys using these metals as a main component. A "main component" is a component that constitutes 51 atomic % or more of the plating layer. For example, the plating layer may contain copper as a main component.

[0064] The seed layer 201 may include a metallic material such as copper, nickel, titanium, chromium, zinc, etc. The seed layer 201 may also include a compound of these metallic materials.

[0065] The structures of the closing electrode 21, the first filling electrode 27 and the second filling electrode 28 will now be described.

[0066] 3, the closing electrode 21 includes a first boundary 211 and a second boundary 212. The first boundary 211 is the boundary between the closing electrode 21 and the first fill electrode 27. The second boundary 212 is the boundary between the closing electrode 21 and the second fill electrode 28.

[0067] 3 , the closing electrode 21 includes at least a closing portion 23, a first portion 24, and a second portion 25. The closing portion 23 is located at the minimum portion 163. The closing portion 23 closes the space of the through-hole 15 located inside the seed layer 201 at least at the minimum portion 163. "Closing" means that the space of the through-hole 15 is shielded with a solid object in the planar direction of the first surface 13.

[0068] "Constituent element A is located inside constituent element B" means that, in the planar direction of first surface 13, the distance from constituent element A to central axis L1 of through hole 15 is smaller than the distance from constituent element B to central axis L1. Conversely, "constituent element A is located outside constituent element B" means that, in the planar direction of first surface 13, the distance from constituent element A to central axis L1 is larger than the distance from constituent element B to central axis L1.

[0069] The central axis L1 is an imaginary straight line that passes through the center point 151 of the through-hole 15 and extends in the thickness direction of the substrate 12. The center point 151 is the center point of the thinnest part 163 in a plan view. The closed portion 23 is located at least at the center point 151.

[0070] The closing portion 23 may be in contact with the seed layer 201. For example, the closing portion 23 may include a closed contour that is in contact with the seed layer 201 over its entire area in a plan view.

[0071] The closed portion 23 includes a first bottom 231 and a second bottom 232. The first bottom 231 is the portion of the first boundary 211 that is farthest from the first surface 13 in the thickness direction of the substrate 12. The second bottom 232 is the portion of the second boundary 212 that is farthest from the second surface 14 in the thickness direction of the substrate 12.

[0072] The first portion 24 extends along the wall surface 16 from the closed portion 23 to the first surface 13. The first portion 24 may be in contact with the seed layer 201.

[0073] The first portion 24 may include an end surface 241 parallel to the first surface 13. The end surface 241 may be located on the same plane as the first surface 13. "Located on the same plane" means that the distance between the two surfaces in the thickness direction of the substrate 12 is 1.0 μm or less.

[0074] 3 indicates an imaginary boundary between the closed portion 23 and the first portion 24. The first imaginary plane 233 is a plane that passes through the first bottom portion 231 and is parallel to the first surface 13.

[0075] The first portion 24 is formed simultaneously with the closing portion 23 in a closing plating process described below. Therefore, there is no physical boundary between the closing portion 23 and the first portion 24. For example, at least one crystal grain exists so as to straddle the closing portion 23 and the first portion 24.

[0076] The second portion 25 extends along the wall surface 16 from the closed portion 23 to the second surface 14. The second portion 25 may contact the seed layer 201.

[0077] The second portion 25 may include an end surface 251 that is parallel to the second surface 14. The end surface 251 may be located on the same plane as the second surface 14.

[0078] 3 indicates an imaginary boundary between the closed portion 23 and the second portion 25. The second imaginary plane 234 is a plane that passes through the second bottom portion 232 and is parallel to the first surface 13.

[0079] The second portion 25 is formed simultaneously with the closing portion 23 in a closing plating process described below. Therefore, there is no physical boundary between the closing portion 23 and the second portion 25. For example, at least one crystal grain exists so as to straddle the closing portion 23 and the second portion 25.

[0080] First filling electrode 27 is located inside first portion 24. First filling electrode 27 is located between closed portion 23 and first surface 13 in the thickness direction of substrate 12. First filling electrode 27 may overlap central axis L1.

[0081] First fill electrode 27 may include end surface 271. End surface 271 may be located on the same plane as first surface 13. End surface 271 may be surrounded by end surface 241 of first portion 24 in a plan view.

[0082] Second filling electrode 28 is located inside second portion 25. Second filling electrode 28 is located between closed portion 23 and second surface 14 in the thickness direction of substrate 12. Second filling electrode 28 may overlap central axis L1.

[0083] Second filling electrode 28 may include an end surface 281. End surface 281 may be located on the same plane as second surface 14. End surface 281 may be surrounded by end surface 251 of second portion 25 in a plan view.

[0084] The dimensions of the components of the through electrode 20 will be described with reference to Fig. 4A. Fig. 4A is a cross-sectional view showing an example of the dimensions of the through electrode 20.

[0085] 4A , symbol K1 represents the distance from the first surface 13 to the first bottom 231 of the closed portion 23 in the thickness direction of the substrate 12. Distance K1 is also referred to as the first distance. Symbol K2 represents the distance from the second surface 14 to the second bottom 232 of the closed portion 23 in the thickness direction of the substrate 12. Distance K2 is also referred to as the second distance. Symbol T5 represents the thickness of the closed portion 23. The thickness T5 is calculated by subtracting the first distance K1 and the second distance K2 from the thickness T0 of the substrate 12. That is, T5 = T0 - (K1 + K2).

[0086] The ratio T5 / T0 of the thickness T5 of the closing portion 23 to the thickness T0 of the substrate 12 is, for example, 0.05 or more, or may be 0.10 or more, or may be 0.20 or more. The ratio T5 / T0 is, for example, 0.50 or less, or may be 0.40 or less, or may be 0.30 or less.

[0087] The ratio K1 / T0 of the first distance K1 to the thickness T0 of the substrate 12 is, for example, 0.10 or more, or may be 0.15 or more, or may be 0.20 or more. The ratio K1 / T0 is, for example, 0.40 or less, or may be 0.35 or less, or may be 0.30 or less.

[0088] The ratio K2 / T0 of the second distance K2 to the thickness T0 of the substrate 12 is, for example, 0.10 or more, or may be 0.15 or more, or may be 0.20 or more. The ratio K2 / T0 is, for example, 0.40 or less, or may be 0.35 or less, or may be 0.30 or less. The ratio K2 / T0 may be the same as or different from the ratio K1 / T0.

[0089] End face 271 of first filling electrode 27 has dimension W1 in the plane direction of first surface 13. As described below, in the process of forming first filling electrode 27 by plating, the process is controlled so that first filling electrode 27 grows preferentially in the thickness direction of substrate 12. Therefore, it is possible to increase K1 / W1, which is the ratio of first distance K1 to dimension W1, while suppressing the occurrence of defects such as voids in first filling electrode 27. Ratio K1 / W1 is, for example, 1.0 or more, or may be 1.2 or more, or 1.5 or more. Ratio K1 / W1 is, for example, 4.0 or less, or may be 3.0 or less, or may be 2.5 or less.

[0090] End face 281 of second filling electrode 28 has dimension W2 in the planar direction of first surface 13. As with first filling electrode 27, in the process of forming second filling electrode 28 by plating, the process is controlled so that second filling electrode 28 grows preferentially in the thickness direction of substrate 12. Therefore, it is possible to increase K2 / W2, which is the ratio of second distance K2 to dimension W2, while suppressing the occurrence of defects such as voids in second filling electrode 28. The numerical range of ratio K2 / W2 may be the same as the numerical range of ratio K1 / W1 described above.

[0091] In FIG. 4A , the symbol θ1 represents the angle between the first surface 13 and the wall surface 16 at the first end 161. The angle θ1 may be greater than 90°. Because the through-hole 15 includes a minimum portion 163, the angle θ1 can be greater than 90°. The angle θ1 is, for example, 95° or greater, 100° or greater, or 105° or greater. The angle θ1 is, for example, 150° or less, 135° or less, or 120° or less.

[0092] 4A , the symbol θ2 represents the angle between the second surface 14 and the wall surface 16 at the second end 162. Like the angle θ1, the angle θ2 may be greater than 90°. The numerical range for the angle θ2 may be the same as the numerical range for the angle θ1 described above.

[0093] When the thermal expansion coefficient of the through electrode 20 differs from the thermal expansion coefficient of the substrate 12, a change in the temperature of the through electrode 20 causes expansion or contraction of the through electrode 20 relative to the substrate 12. The expansion or contraction generates stress between the substrate 12 and the through electrode 20. Stress caused by a change in temperature is also called thermal stress. When expansion or contraction occurs in the through electrode 20, it is thought that large thermal stress is generated at the first end 161 and the second end 162 of the through hole 15.

[0094] In the first embodiment, since the through hole 15 includes the narrowest portion 163, the angles θ1 and θ2 can be greater than 90°. The angles θ1 and θ2 being greater than 90° can reduce thermal stress at the first end 161 and the second end 162.

[0095] In the first embodiment, the thermal stress at the first end 161 and the second end 162 is reduced, so the distance between two adjacent through holes 15 can be made smaller than in a conventional through electrode substrate. Therefore, for example, the first dimension R1 and the second dimension R2 of the through holes 15 can be increased while maintaining the same arrangement pitch as in a conventional through electrode substrate. By increasing the first dimension R1 and the second dimension R2, the allowable current of the through electrode 20 can be increased. In this way, according to the first embodiment, both the thermodynamic reliability and the electrical characteristics can be improved.

[0096] 1, the arrangement pitch P is the distance between the centers of two adjacent through holes 15. R1 / P, which is the ratio of the first dimension R1 to the arrangement pitch P, is, for example, 0.1 or more, and may be 0.2 or more. R1 / P is, for example, 0.5 or less, and may be 0.4 or less.

[0097] 4A , the reference symbol T3 denotes the thickness of the first portion 24 of the closing electrode 21. The thickness T3 of the first portion 24 is determined at a position that is a distance S3 away from the first surface 13 in the thickness direction of the substrate 12. The distance S3 is 50 μm. The reference symbol T4 denotes the thickness of the second portion 25 of the closing electrode 21. The thickness T4 of the second portion 25 is determined at a position that is a distance S4 away from the second surface 14 in the thickness direction of the substrate 12. The distance S4 is 50 μm. Both the thickness T3 and the thickness T4 are measured in the plane direction of the first surface 13.

[0098] The thickness T3 and the thickness T4 are, for example, 2.0 μm or more, or may be 4.0 μm or more, or 7.0 μm or more. The thickness T3 and the thickness T4 are, for example, 15.0 μm or less, or may be 12.0 μm or less, or may be 10.0 μm or less.

[0099] By appropriately setting the upper limits of the thickness T3 and the thickness T4, the uniformity of the thickness of the first portion 24 and the thickness of the second portion 25 can be ensured.

[0100] The thickness uniformity of the first portion 24 is evaluated by measuring the thickness of the first portion 24 at multiple positions in the thickness direction of the substrate 12. For example, if the difference between the maximum and minimum values ​​of the thicknesses T3, T31, and T32 of the first portion 24 is 0.10 μm or less, the thickness variation of the first portion 24 is determined to be 0.10 μm or less. The thickness T3 is measured at a position that is a distance S3 away from the first surface 13 in the thickness direction of the substrate 12. The thickness T31 is measured at a position that is (S3 + 20 μm) away from the first surface 13 in the thickness direction of the substrate 12. The thickness T32 is measured at a position that is (S3 - 20 μm) away from the first surface 13 in the thickness direction of the substrate 12.

[0101] As with the first portion 24, the thickness uniformity of the second portion 25 is evaluated by measuring the thickness of the second portion 25 at multiple positions in the thickness direction of the substrate 12. For example, if the difference between the maximum and minimum values ​​of the thicknesses T4, T41, and T42 of the second portion 25 is 0.10 μm or less, the thickness variation of the second portion 25 is determined to be 0.10 μm or less. The thickness T4 is measured at a position that is a distance S4 away from the second surface 14 in the thickness direction of the substrate 12. The thickness T41 is measured at a position that is (S4 + 20 μm) away from the second surface 14 in the thickness direction of the substrate 12. The thickness T42 is measured at a position that is (S4 - 20 μm) away from the second surface 14 in the thickness direction of the substrate 12.

[0102] The above-mentioned distances and dimensions of the substrate 12 and the through electrode 20 are calculated based on an image of a cross section of the through electrode substrate 10 obtained by an electron microscope. The cross section is obtained by cutting the through electrode substrate 10 along a cutting plane that passes through the center point 151 of the through hole 15 and is perpendicular to the first surface 13.

[0103] 4B is an enlarged cross-sectional view showing a portion of the through electrode 20. The through electrode substrate 10 may include an adhesion layer 17 located between the through electrode 20 and the wall surface 16. The adhesion layer 17 may be in contact with the wall surface 16.

[0104] The adhesion layer 17 is a layer for increasing the adhesion of the through electrode 20 to the wall surface 16. For example, the adhesion layer 17 can suppress the occurrence of a gap between the through electrode 20 and the wall surface 16. When the through electrode 20 includes a seed layer 201, the adhesion layer 17 is located between the seed layer 201 and the wall surface 16. The adhesion layer 17 may be in contact with the seed layer 201.

[0105] 4B , the adhesive layer 17 may be located over the entire wall surface 16. Although not shown, the adhesive layer 17 may be located over only a portion of the wall surface 16. In other words, the wall surface 16 may include a portion that is not covered by the adhesive layer 17.

[0106] The adhesion layer 17 includes a material that has adhesiveness to the wall surface 16. For example, the adhesion layer 17 may be made of titanium or a titanium compound. Examples of titanium compounds include titanium oxide (TiO2) and titanium nitride (TiN).

[0107] The thickness of the adhesion layer 17 is, for example, 5 nm or more, optionally 10 nm or more, or 20 nm or more. The thickness of the adhesion layer 17 is, for example, 300 nm or less, optionally 100 nm or less, or optionally 50 nm or less.

[0108] As shown in FIG. 4B , a step H1 in the thickness direction of the substrate 12 may be present between an end face 241 of the first portion 24 of the through electrode 20 and the first surface 13. The end face 241 may protrude from the first surface 13 or may be recessed from the first surface 13. In the example shown in FIG. 4B , the end face 241 protrudes from the first surface 13. "The end face 241 protrudes from the first surface 13" means that the distance between the end face 241 and the second surface 14 in the thickness direction of the substrate 12 is greater than the distance between the first surface 13 and the second surface 14. "The end face 241 is recessed from the first surface 13" means that the distance between the end face 241 and the second surface 14 in the thickness direction of the substrate 12 is smaller than the distance between the first surface 13 and the second surface 14.

[0109] As will be described later with reference to FIG. 12 , in the manufacturing process of the through electrode substrate 10, a first polishing step may be performed after the through electrodes 20 are formed in the through holes 15. In the first polishing step, layers that are located on the first surface 13 and are continuous with each component of the through electrodes 20 are removed, for example, by chemical mechanical polishing. In the first polishing step, the first surface 13 of the substrate 12 may also be polished. The degree to which each layer and the substrate 12 are polished by the first polishing step may vary depending on the mechanical properties of the material, etc. As a result, the above-mentioned step H1 may occur.

[0110] The step height H1 is, for example, 5.0 μm or less, and may be 3.0 μm or less, 2.0 μm or less, 1.0 μm or less, 0.6 μm or less, or 0.4 μm or less. The step height H1 is, for example, 0.1 μm or more, 0.2 μm or more, or 0.3 μm or more.

[0111] As described above, when the through electrode 20 expands or contracts, thermal stress is thought to occur at the first end 161 of the through hole 15. When the step H1 is present, the thermal stress occurring at the first end 161 is reduced. Therefore, damage to the substrate 12 can be suppressed.

[0112] As shown in FIG. 4B , a step H2 may exist in the thickness direction of the substrate 12 between an end face 251 of the second portion 25 of the through electrode 20 and the second surface 14. The end face 251 may protrude from the second surface 14 or may be recessed from the second surface 14. In the example shown in FIG. 4B , the end face 251 protrudes from the second surface 14. "The end face 251 protrudes from the second surface 14" means that the distance between the end face 251 and the first surface 13 in the thickness direction of the substrate 12 is greater than the distance between the second surface 14 and the first surface 13. "The end face 251 is recessed from the second surface 14" means that the distance between the end face 251 and the first surface 13 in the thickness direction of the substrate 12 is smaller than the distance between the second surface 14 and the first surface 13.

[0113] 12 described later, in the manufacturing process of the through electrode substrate 10, a second polishing step may be performed after the through electrodes 20 are formed in the through holes 15. Similar to the step H1 described above, the step H2 may also be generated by the second polishing step.

[0114] The numerical range of the step height H2 may be the same as the numerical range described above for the step height H1.

[0115] As described above, when the through electrode 20 expands or contracts, thermal stress is thought to occur at the second end 162 of the through hole 15. When the step H2 is present, the thermal stress occurring at the second end 162 is reduced. Therefore, damage to the substrate 12 can be suppressed.

[0116] In FIG. 4B , the symbol φ1 represents the angle formed by the line L11 and the line L01. The line L11 is a line passing through the smallest portion 163 and the first end 161 of the through hole 15 in the cross-sectional view of the through electrode substrate 10. The line L01 is a line perpendicular to the first surface 13. The angle φ1 is, for example, 1.0° or more, and may be 1.5° or more. The angle φ1 is, for example, 4.0° or less, and may be 3.0° or less. The angle φ1 may be 2.0°.

[0117] Since substrate 12 has angle φ1, the process of forming through hole 15 in substrate 12 becomes industrially easier. Furthermore, since substrate 12 has angle φ1, stress applied to substrate 12 is reduced. Furthermore, since substrate 12 has angle φ1, the plating process for forming first filling electrode 27 is easier. Furthermore, since substrate 12 has angle φ1, the volume of first filling electrode 27 increases, thereby increasing the allowable current of through electrode 20.

[0118] 4B , the symbol φ2 represents the angle formed by the line L12 and the line L02. The line L12 is a line passing through the smallest portion 163 and the second end 162 of the through hole 15 in the cross-sectional view of the through hole electrode substrate 10. The line L02 is a line perpendicular to the second surface 14. The numerical range of the angle φ2 may be the same as the above-mentioned numerical range for the angle φ1.

[0119] Since substrate 12 has angle φ2, the process of forming through hole 15 in substrate 12 becomes industrially easier. Furthermore, since substrate 12 has angle φ2, stress applied to substrate 12 is reduced. Furthermore, since substrate 12 has angle φ2, the plating process for forming second filling electrode 28 is easier. Furthermore, since substrate 12 has angle φ2, the volume of second filling electrode 28 increases, thereby increasing the allowable current of through electrode 20.

[0120] The wall surface 16 of the through-hole 15 may have reduced roughness. When the through-hole 15 is formed by etching, the roughness of the wall surface 16 can be reduced by adjusting the etching method, time, etc.

[0121] The roughness of the wall surface 16 of the through hole 15 may be expressed by an average roughness Ra. The average roughness Ra of the wall surface 16 is, for example, 0.4 μm or less.

[0122] The roughness of the wall surface 16 of the through hole 15 may be expressed by a maximum height Rz. The maximum height Rz of the wall surface 16 is, for example, 1.4 μm or less.

[0123] A sample for measuring the roughness of the wall surface 16 is prepared by exposing the wall surface 16 of a portion of the through hole 15 in the through electrode substrate 10. In the process of exposing the wall surface 16, a scribe and break technique is used.

[0124] The average roughness Ra and maximum height Rz are calculated based on the results of measuring the shape of the wall surface 16 over the entire area of ​​the wall surface 16 in the thickness direction of the substrate 12. The shape of the wall surface 16 is measured using a white light interferometer. The magnification during measurement is, for example, 20 times. The measurement results of the shape of the wall surface 16 are filtered using a cutoff in accordance with ISO 4288 (04 / 98). The average roughness Ra and maximum height Rz are calculated based on the filtered shape of the wall surface 16.

[0125] The cross-sectional structure of the through electrode 20 will be described below. Fig. 5 is a diagram showing an example of the cross-sectional structure of the closing electrode 21 and the second filling electrode 28.

[0126] The closing electrode 21 includes a plurality of crystal grains 29. The crystal grains 29 of the closing electrode 21 are also referred to as first crystal grains. The plurality of first crystal grains 29 of the closing electrode 21 are formed by a closing plating process, which will be described later.

[0127] Each of first and second fill electrodes 27, 28 includes a plurality of crystal grains 30. The crystal grains 30 of first and second fill electrodes 27, 28 are also referred to as second crystal grains. The plurality of second crystal grains 30 of first and second fill electrodes 27, 28 are formed by a fill plating process described below.

[0128] The plurality of first crystal grains 29 and the plurality of second crystal grains 30 may both contain the same metal material as a main component. The "main component" is a component that constitutes 51 atomic % or more of the plurality of first crystal grains 29 and the plurality of second crystal grains 30. For example, the first crystal grains 29 and the second crystal grains 30 may each contain copper as a main component.

[0129] The composition of first crystal grains 29 is calculated by analyzing the composition of closed portion 23 using XPS. The composition of second crystal grains 30 is calculated by analyzing the compositions of first filler electrode 27 and second filler electrode 28, respectively, using XPS.

[0130] A sample for analysis is obtained by cutting the through hole electrode substrate 10 along a cutting plane that passes through the center point 151 of the through hole 15 and is perpendicular to the first surface 13. In a composition analysis of the closed portion 23, a region of the closed portion 23 including the center point 151 of the through hole 15 is measured by the XPS method. In a composition analysis of the first filling electrode 27, a region of the first filling electrode 27 that is a distance K5 from the first bottom 231 in the thickness direction of the substrate 12 is measured by the XPS method. The distance K5 is 100 μm. In a composition analysis of the second filling electrode 28, a region of the second filling electrode 28 that is a distance K6 from the second bottom 232 in the thickness direction of the substrate 12 is measured by the XPS method. The distance K6 is 100 μm.

[0131] The XPS settings for composition analysis were as follows: Incident X-ray: Mg Kα, hν = 1253.6 eV X-ray output: 10 kV, 20 mA (200 W) X-ray incident angle: 45° Photoelectron acceptance angle: 90° Measurement area: 100 μmφ Peak shift correction: Corrected so that the CC peak in the C1s peak is 285.0 eV Charge neutralization: Not performed Waveform separation of narrow peaks: Performed using the GL function (a mixed function of Gaussian and Lorentzian functions) in the analysis software provided with the instrument Etching ions: Ar gas cluster ion beam (Ar-G CIB) Etching ion acceleration voltage: 5.0 kV

[0132] The filling plating step is performed after the closing plating step. In the initial stage of the filling plating step, the second crystal grains 30 grow from the first boundary 211 or the second boundary 212 as a starting point.

[0133] As shown in Fig. 5, the plurality of second crystal grains 30 of second filler electrode 28 may include at least one linear crystal grain. A linear crystal grain is a crystal grain having a grain boundary including a pair of linear grain boundaries 301 extending parallel to each other. As shown in Fig. 5, the pair of linear grain boundaries 301 may be in contact with second boundary 212. In other words, the linear crystal grain may be formed by growth starting from second boundary 212.

[0134] The length of the pair of linear grain boundaries 301 is, for example, 100 nm or more, or may be 200 nm or more, or may be 300 nm or more.

[0135] The ratio of the length of the pair of linear grain boundaries 301 to the distance between the pair of linear grain boundaries 301 may be, for example, 2.0 or more, or may be 3.0 or more, or may be 5.0 or more.

[0136] Although not shown, the plurality of second crystal grains 30 of first fill electrode 27 may also include at least one linear crystal grain. The linear crystal grain of first fill electrode 27 may also have grain boundaries including a pair of linear grain boundaries that contact first boundary 211. In other words, the linear crystal grain of first fill electrode 27 may be formed by growth starting from first boundary 211.

[0137] The average cross-sectional area of ​​the plurality of first crystal grains 29 is also referred to as a first average cross-sectional area SQ1. The average cross-sectional area of ​​the plurality of second crystal grains 30 is also referred to as a second average cross-sectional area SQ2. The second average cross-sectional area SQ2 may be different from the first average cross-sectional area SQ1.

[0138] The second average cross-sectional area SQ2 may be larger than the first average cross-sectional area SQ1. The ratio SQ2 / SQ1 of the second average cross-sectional area SQ2 to the first average cross-sectional area SQ1 is, for example, 1.1 or more, or may be 1.3 or more, or may be 1.5 or more. The ratio SQ2 / SQ1 is, for example, 5.0 or less, or may be 3.0 or less, or may be 2.0 or less.

[0139] The average cross-sectional area of ​​the multiple crystal grains is calculated by dividing the area of ​​the cross-sectional image of the sample by the number of crystal grains that appear in the cross-sectional image. The cross-sectional image is obtained by observing the cross-section of the sample using a scanning transmission electron microscope (hereinafter also referred to as STEM). The cross-sectional image is obtained for each of the 10 through electrodes 20. The observation conditions using the STEM are as follows: Observation magnification: 45,000 times; Acceleration voltage: 200 kV

[0140] When measuring the average cross-sectional area of ​​the plurality of first crystal grains 29 of closing electrode 21, a region of closing portion 23 including center point 151 of through-hole 15 is observed by STEM. When measuring the average cross-sectional area of ​​the plurality of second crystal grains 30 of first filling electrode 27, a region of first filling electrode 27 that is a distance K5 away from first bottom 231 in the thickness direction of substrate 12 is observed by STEM. Distance K5 is 100 μm. When measuring the average cross-sectional area of ​​the plurality of second crystal grains 30 of second filling electrode 28, a region of second filling electrode 28 that is a distance K6 away from second bottom 232 in the thickness direction of substrate 12 is observed by STEM. Distance K6 is 100 μm.

[0141] The average crystal grain size of the plurality of first crystal grains 29 is also referred to as a first average crystal grain size SR1. The average crystal grain size of the plurality of second crystal grains 30 is also referred to as a second average crystal grain size SR2. The average crystal grain size is a circle-equivalent diameter. The circle-equivalent diameter is calculated under the assumption that each of the plurality of crystal grains has a perfect circular shape in the cross section of the through electrode 20. The average crystal grain size SR of crystal grains having an average cross-sectional area SQ is expressed by the following formula: SR=2×(SQ / π) ０．５

[0142] As described above, a cross-sectional image of the through electrode 20 for calculating the average cross-sectional area of ​​a plurality of crystal grains is obtained by observing the cross section of the sample using a STEM. One specific example of a STEM is a high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM). For example, an HD-2700 manufactured by Hitachi High-Technologies Corporation is used. The conditions for observation using the STEM are as follows: Observation magnification: 45,000 (30,000 x 1.5) times; Acceleration voltage: 200 kV.

[0143] Generally, the smaller the average grain size, the stronger the material, a phenomenon known as the "grain refinement effect."

[0144] The first crystal grains 29 may have a relatively small first average crystal grain size SR1. The first average crystal grain size SR1 is, for example, 50 nm or more, or may be 100 nm or more, 150 nm or more, or 200 nm or more. The first average crystal grain size SR1 is, for example, less than 500 nm, or may be 400 nm or less, or may be 300 nm or less. The first average crystal grain size SR1 may be 250 nm. When the average crystal grain size of a material containing copper as a main component is 250 nm, the hardness of the material is, for example, 160 Hv.

[0145] The fact that the first crystal grains 29 have a small first average crystal grain size SR1 can give the material the following characteristics. (Strength) A material with a small average crystal grain size contains many crystal grain boundaries, making it difficult for fracture to progress and improving strength. This is because the crystal grain boundaries hinder sliding. (Ductility) The smaller the average crystal grain size, the lower the ductility of the material. In particular, if the average crystal grain size is extremely small, the material is more likely to become embrittled. (Fatigue strength) The smaller the average crystal grain size, the higher the fatigue strength of the material. This is because the crystal grain boundaries suppress the occurrence of fatigue cracks.

[0146] The second crystal grains 30 may have a relatively large second average crystal grain size SR2. The second average crystal grain size SR2 of the second crystal grains 30 may be larger than the first average crystal grain size SR1 of the first crystal grains 29. The second average crystal grain size SR2 is, for example, 500 nm or more, 700 nm or more, or 900 nm or more. The second average crystal grain size SR2 is, for example, 2.0 μm or less, 1.5 μm or less, or 1.2 μm or less. The second average crystal grain size SR2 may be 1.0 μm. When the average crystal grain size of a material containing copper as a main component is 1.0 μm, the hardness of the material is, for example, 110 Hv.

[0147] The second crystal grains 30 having a large second average crystal grain size SR2 can provide the following characteristics to the material. (Toughness) The larger the average crystal grain size, the more the toughness of the material improves. Toughness is the ability to resist impact. (Ductility) The larger the average crystal grain size, the more the ductility of the material improves.

[0148] The reliability of the through hole electrode substrate 10, including the glass substrate 12, is affected by the mechanical properties of the first and second filler electrodes 27 and 28. For example, the higher the toughness and ductility of the first and second filler electrodes 27 and 28, the higher the reliability of the through hole electrode substrate 10. This is because the higher the toughness and ductility of the first and second filler electrodes 27 and 28, the more the first and second filler electrodes 27 and 28 can relieve stress caused by the difference in thermal expansion coefficient between the closing electrode 21 and the glass substrate 12. Therefore, when the second crystal grains 30 have a large second average crystal grain size SR2, the reliability of the through hole electrode substrate 10 can be improved.

[0149] (Method for Manufacturing the Through Electrode Substrate) An example of a method for manufacturing the through electrode substrate 10 will be described.

[0150] (Through hole forming process) The substrate 12 is prepared. Next, a resist layer is provided on at least one of the first surface 13 or the second surface 14. Next, an opening is provided in the resist layer at a position corresponding to the through hole 15. Next, the substrate 12 is processed through the opening in the resist layer. As a result, as shown in FIG. 6 , the through hole 15 is formed in the substrate 12. The through hole 15 includes a wall surface 16 extending from the first surface 13 to the second surface 14. Methods that can be used to process the substrate 12 include dry etching, wet etching, and the like. Dry etching methods include reactive ion etching, deep reactive ion etching, and the like.

[0151] The through holes 15 may be formed in the substrate 12 by irradiating the substrate 12 with a laser. In this case, a resist layer does not need to be provided. The laser may be an excimer laser, an Nd:YAG laser, a femtosecond laser, or the like. When an Nd:YAG laser is used, a fundamental wave with a wavelength of 1064 nm, a second harmonic with a wavelength of 532 nm, or a third harmonic with a wavelength of 355 nm may be used.

[0152] The process of forming the through hole 15 in the substrate 12 may include a process of irradiating the first surface 13 and the second surface 14 of the substrate 12 with a laser and a wet etching process. In this case, the laser is used not to process the substrate 12, but to partially form modified layers on the first surface 13 and the second surface 14 of the substrate 12. In the wet etching process, the modified layer is preferentially etched compared to other portions. By wet etching, a recess is formed in the modified layer on the first surface 13, and a recess is formed in the modified layer on the second surface 14. The recess on the first surface 13 and the recess on the second surface 14 are connected to form the through hole 15 having a wall surface extending from the first surface 13 to the second surface 14.

[0153] (Through Electrode Forming Step) Subsequently, a through electrode forming step is performed to form the through electrode 20 in the through hole 15. The through electrode forming step includes a seed layer forming step and a plating step.

[0154] 7, in the seed layer formation step, a seed layer 201 is formed on the first surface 13, the second surface 14, and the wall surface 16 of the substrate 12. For example, the seed layer 201 is formed by sputtering.

[0155] In the plating step, a plating layer is deposited by electrolytic plating. The plating step includes at least a closing plating step and a filling plating step.

[0156] In the closed plating process, a closed electrode 21 is formed. FIGS. 8 and 9 are cross-sectional views showing an example of the closed plating process. In the closed plating process, the substrate 12 on which a seed layer 201 is formed may be immersed in a plating solution. By passing a current through the seed layer 201, a plating layer 203 is deposited on the seed layer 201, as shown in FIGS. 8 and 9. The plating layer 203 formed in the closed plating process is also referred to as the closed plating layer 203. The plating solution used to form the closed portion 23, the first portion 24, and the second portion 25 in the closed plating process is also referred to as the second plating solution.

[0157] The second plating solution may contain an additive. The type and concentration of the additive determine, for example, the direction in which the closing plating layer 203 preferentially grows. The concentration of the additive in the second plating solution is also referred to as a second concentration. The second concentration may be set so that the closing plating layer 203 grows appropriately in the normal direction of the wall surface 16 of the through hole 15.

[0158] The second concentration may be set so that the first average grain size SR1 of the plurality of first grains 29 of the closing electrode 21 falls within the above-mentioned numerical range.

[0159] The additives may include an inhibitor, an accelerator, etc. The inhibitor acts to inhibit the growth of the plating layer in the normal direction of the wall surface 16 of the through hole 15. The inhibitor may be a suppressor or a leveler. An example of a suppressor is a polyether such as polyethylene glycol. The suppressor causes a phenomenon in which molecules or the like adhere to the surface of the plating layer, thereby inhibiting the plating reaction. An example of a leveler is a cationic compound such as Janus Green B. The leveler causes a phenomenon in which molecules or ions are adsorbed or precipitated on the surface of the plating layer, thereby inhibiting the plating reaction.

[0160] In the closing plating step, by setting the second concentration to a low value, it is possible to achieve appropriate growth of the closing plating layer 203 in the normal direction of the wall surface 16 of the through hole 15 .

[0161] The density of the current flowing through the seed layer 201 in the closing plating process is also referred to as the second current density. The second current density may be set so that the first average grain size SR1 of the plurality of first grains 29 of the closing electrode 21 falls within the above-mentioned numerical range. Generally, the higher the current density, the smaller the average grain size.

[0162] The through hole 15 of the substrate 12 includes a minimum portion 163. As the growth of the closing plating layer 203 progresses, the closing plating layers 203 formed along the circumferential direction of the through hole 15 in the minimum portion 163 are connected to each other. That is, as shown in FIG. 9 , the through hole 15 is closed by the closing plating layer 203 in the minimum portion 163. That is, a closed portion 23 is formed.

[0163] In the closing plating process, a closing plating layer 203 is also formed in a region of the seed layer 201 located between the minimum portion 163 and the first surface 13 in the thickness direction. In the closing plating process, a closing plating layer 203 is also formed in a region of the seed layer 201 located between the minimum portion 163 and the second surface 14 in the thickness direction. The closing plating layer 203 formed in the region of the seed layer 201 located between the minimum portion 163 and the first surface 13 in the thickness direction constitutes the first portion 24. The closing plating layer 203 formed in the region of the seed layer 201 located between the minimum portion 163 and the second surface 14 in the thickness direction constitutes the second portion 25. By the closing plating process, a closing electrode 21 including a closing portion 23, a first portion 24, and a second portion 25 is obtained.

[0164] In a closing plating step after the through-hole 15 is closed by the closing portion 23, the second plating solution circulates in the first space SP1 and the second space SP2. The first space SP1 is the space of the through-hole 15 located between the minimum portion 163 and the first surface 13 in the thickness direction of the substrate 12. The second space SP2 is the space of the through-hole 15 located between the minimum portion 163 and the second surface 14 in the thickness direction of the substrate 12.

[0165] The time and current density of the closing plating process are adjusted to achieve the above-mentioned numerical ranges for the first distance K1, the second distance K2, the thickness T5 of the closing portion 23, etc. For example, the closing plating process is carried out so that the ratio of the thickness T5 of the closing portion 23 to the thickness T0 of the substrate 12 falls within the above-mentioned numerical ranges.

[0166] In the filling plating process, a first filling electrode 27 and a second filling electrode 28 are formed. FIGS. 10 and 11 are cross-sectional views showing an example of the filling plating process. In the filling plating process, the substrate 12 on which the seed layer 201 and the closing plating layer 203 are formed may be immersed in a plating solution different from the second plating solution described above. By passing a current through the seed layer 201 and the closing plating layer 203, a plating layer 204 is deposited on the closing plating layer 203, as shown in FIGS. 10 and 11 . The plating layer 204 formed in the filling plating process is also referred to as the filling plating layer 204. The plating solution used in the filling plating process is also referred to as the third plating solution.

[0167] The third plating solution may contain an additive. The type and concentration of the additive determine, for example, the direction in which the growth of the fill plating layer 204 preferentially occurs. The concentration of the additive in the third plating solution is also referred to as a third concentration.

[0168] In the filling plating process, it is preferable that the growth rate of the filling plating layer 204 in the thickness direction of the substrate 12 is greater than the growth rate of the filling plating layer 204 in the normal direction of the wall surface 16. Therefore, the third concentration is preferably set so that the filling plating layer 204 grows preferentially in the thickness direction of the substrate 12.

[0169] The third concentration may be set so that the second average grain size SR2 of the plurality of second grains 30 in first fill electrode 27 and second fill electrode 28 falls within the above-mentioned numerical range.

[0170] The additives of the third plating solution may include a suppressor, an accelerator, etc., similar to the additives of the second plating solution. The type of additives of the third plating solution may be the same as the type of additives of the second plating solution. For example, the additives of the second plating solution and the additives of the third plating solution may both be suppressors that suppress the growth of the plating layer in the normal direction of the wall surface 16. For example, the additives of the second plating solution and the additives of the third plating solution may both be accelerators that promote the growth of the plating layer in the recesses. A "recess" refers to a portion surrounded by a plating layer, such as the first bottom 231.

[0171] The third concentration of the additive in the third plating solution may be higher than the second concentration of the additive in the second plating solution. As a result, in the filling plating process, the filling plating layer 204 can grow preferentially in the thickness direction of the substrate 12. For example, the growth rate of the filling plating layer 204 in the thickness direction of the substrate 12, starting from the first bottom 231 and the second bottom 232 of the closed portion 23, is higher than the growth rate of the filling plating layer 204 starting from the first portion 24 and the second portion 25. Therefore, the occurrence of defects such as voids in the filling plating layer 204 is suppressed.

[0172] The density of the current flowing through seed layer 201 during the fill plating process is also referred to as the third current density. The third current density may be set so that the second average grain size SR2 of the plurality of second grains 30 of first filler electrode 27 and second filler electrode 28 falls within the above-mentioned numerical range. In general, the smaller the current density, the larger the average grain size.

[0173] The filling plating process may be performed until the growth of filling plating layer 204 reaches the position of first surface 13 in the thickness direction of substrate 12. Filling plating layer 204 formed inside first portion 24 constitutes first filling electrode 27.

[0174] The filling plating process may be performed until the growth of filling plating layer 204 reaches the position of second surface 14 in the thickness direction of substrate 12. Filling plating layer 204 formed inside second portion 25 constitutes second filling electrode 28.

[0175] Subsequently, as shown in FIG. 12 , a polishing process may be performed. The polishing process may include at least one of a first polishing process and a second polishing process. In the example shown in FIG. 12 , the polishing process includes a first polishing process and a second polishing process. In the first polishing process, the seed layer 201, the closing plating layer 203, and the filling plating layer 204 located on the first surface 13 are removed by polishing. In the second polishing process, the seed layer 201, the closing plating layer 203, and the filling plating layer 204 located on the second surface 14 are removed by polishing. The polishing is, for example, chemical mechanical polishing.

[0176] The first polishing step forms end face 241 on first portion 24 and end face 271 on first filling electrode 27. The second polishing step forms end face 251 on second portion 25 and end face 281 on second filling electrode 28.

[0177] As shown in FIG. 12, a through electrode substrate 10 is obtained by forming a through electrode 20 in the through hole 15 .

[0178] In the through electrode substrate 10 of the first embodiment, the through electrodes 20 are filled over almost the entire area of ​​the through holes 15. Therefore, the allowable current of the through electrodes 20 is increased compared to when the through electrodes 20 are formed only in a part of the through holes 15. For example, the through electrodes 20 of the first embodiment have a higher allowable current compared to when the through holes 15 are filled with not only the through electrodes 20 but also a resin material.

[0179] In the first embodiment, the through electrode 20 includes a closing electrode 21, a first filling electrode 27, and a second filling electrode 28. The first filling electrode 27 and the second filling electrode 28 are formed under plating conditions different from those for the closing electrode 21. For example, the filling plating process is controlled so that the filling plating layer 204 grows preferentially in the thickness direction of the substrate 12. Therefore, the occurrence of defects such as voids in the first filling electrode 27 and the second filling electrode 28 is suppressed.

[0180] The advantages of the manufacturing method of the first embodiment will be described based on the differences from the first comparative embodiment, in which the plating process for forming the through electrode 20 that fills almost the entire area of ​​the through hole 15 is performed under a single plating condition.

[0181] 13 and 14 are cross-sectional views illustrating an example of a plating process in the first comparative embodiment. In the first comparative embodiment, after the closed portion 23 is formed in the thinnest portion 163, the plating process continues without changing the plating conditions. Growth of the plating layer 203 in the thickness direction of the substrate 12, starting from the closed portion 23, and growth of the plating layer 203 in the normal direction of the wall surface 16, starting from the first portion 24 and the second portion 25, tend to proceed in a similar manner. In this case, before the growth of the plating layer 203 starting from the closed portion 23 reaches the first surface 13, the through hole 15 may be closed at the first surface 13 by the plating layer 203 starting from the first portion 24. In this case, defects such as voids 205 are likely to occur in the plating layer 203, as shown in FIG. 14 .

[0182] On the other hand, in the first embodiment, first filling electrode 27 and second filling electrode 28 are formed under plating conditions different from those for closing electrode 21. For example, the filling plating process is controlled so that the plating layer grows preferentially in the thickness direction of substrate 12. Therefore, the occurrence of defects such as voids in through electrode 20 is suppressed.

[0183] The advantages of the through electrode substrate 10 of the first embodiment will be described based on the differences with the second comparative embodiment and the third comparative embodiment.

[0184] 15 is a cross-sectional view showing a through hole electrode substrate according to a second comparative example, in which the dimension of through hole 15 in the planar direction of first surface 13 is constant regardless of the position of through hole 15 in the thickness direction.

[0185] In the second comparative example, the larger the dimension of the through hole 15 in the planar direction of the first surface 13, the higher the allowable current of the through electrode 20. However, if the dimension of the through hole 15 becomes too large, defects such as voids are likely to occur in the through electrode 20.

[0186] When the size of the through hole 15 is limited, defects such as voids are suppressed. However, when the size of the through hole 15 is limited, the allowable current of the through electrode 20 cannot be increased sufficiently.

[0187] 16 is a cross-sectional view showing a through electrode substrate according to a third comparative embodiment. In the third comparative embodiment, the through electrode 20 is made of a conductive material filled throughout the through hole 15, as in the second comparative embodiment. In the third comparative embodiment, the dimension of the through hole 15 monotonically decreases from the first surface 13 toward the second surface 14. Therefore, the second dimension R2 is smaller than the first dimension R1. In the vicinity of the second surface 14, defects such as voids are suppressed from occurring in the through electrode 20.

[0188] In the third comparative example, as in the second comparative example, if the first dimension R1 is too large, there is a concern that defects such as voids may occur in the plating layer. On the other hand, if the first dimension R1 is limited to an extent that does not cause defects such as voids, the allowable current of the through electrode 20 cannot be sufficiently increased.

[0189] Consider a case where the plating process of the third comparative embodiment includes a closing plating process and a filling plating process, similar to the first embodiment. In the closing plating process, a plating layer is formed on the second surface 14 to close the through hole 15. In the filling plating process, a plating layer is formed in the space of the through hole 15 where the second surface 14 is closed. By controlling the filling plating process so that the plating layer grows preferentially along the thickness direction of the substrate 12, defects such as voids are reduced. However, in the filling plating process of the third comparative embodiment, the plating layer must grow along the thickness direction of the substrate 12 from the closed portion of the second surface 14 to the first surface 13. Because the growth amount of the plating layer in the thickness direction is large, it is conceivable that the through hole 15 will be closed at the position of the first surface 13 by the plating layer originating from the wall surface 16 before the plating layer reaches the position of the first surface 13.

[0190] In the first embodiment, the dimensions of first filling electrode 27 and second filling electrode 28 formed by the filling plating process in the thickness direction of substrate 12 are reduced compared to the third comparative embodiment. Therefore, in the present embodiment, defects such as voids are suppressed compared to the third comparative embodiment.

[0191] The first embodiment described above can be modified in various ways. Modifications will be described below with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the first embodiment described above will be designated by the same reference numerals as those used for the corresponding parts in the first embodiment described above. Duplicate descriptions will be omitted. Furthermore, if it is clear that the effects obtained in the first embodiment described above can also be obtained in the modification, the description may be omitted.

[0192] 17 is a cross-sectional view showing a through hole electrode substrate 10 in a first modified example. The through hole electrode substrate 10 may include a first conductive layer 35 located on the first surface 13. The first conductive layer 35 is a layer having conductivity. The first conductive layer 35 may be a pad or a wiring.

[0193] The through-hole electrode substrate 10 may include a second conductive layer 36 located on the second surface 14. The second conductive layer 36 is a layer having electrical conductivity. The second conductive layer 36 may be a pad or a wiring.

[0194] 18 is a cross-sectional view showing a through hole electrode substrate 10 in a second modified example. The through hole electrode substrate 10 may include a first surface resin layer 31 located on the first surface 13.

[0195] The first surface resin layer 31 contains an insulating resin material, such as an organic material such as polyimide, epoxy, acrylic, or polyphenyl ether.

[0196] The thickness of the first-side resin layer 31 is, for example, 1.0 μm or more, or may be 2.0 μm or more, or 3.0 μm or more. The thickness of the first-side resin layer 31 is, for example, 20.0 μm or less, or may be 15.0 μm or less, or may be 8.0 μm or less.

[0197] 18 , the first-side resin layer 31 may cover at least a portion of the plurality of first conductive layers 35. An opening 311 may be formed penetrating the first-side resin layer 31. A conductive layer 37 connected to the through electrode 20 or the first conductive layer 35 may be formed in the opening 311.

[0198] The through-hole electrode substrate 10 may include a second-side resin layer 32 located on the second surface 14. The second-side resin layer 32 contains an insulating resin material, similar to the first-side resin layer 31. The thickness of the second-side resin layer 32 may be within the above-mentioned numerical range for the thickness of the first-side resin layer 31.

[0199] 18 , the second-side resin layer 32 may cover at least a portion of the plurality of second conductive layers 36. An opening 321 may be formed penetrating the second-side resin layer 32. A conductive layer 38 connected to the through electrode 20 or the second conductive layer 36 may be formed in the opening 321.

[0200] 19 is a cross-sectional view showing a through electrode 20 in a third modified example. The closing electrode 21 may include a surface portion 22 located between the closing portion 23, the first portion 24, and the second portion 25 and the wall surface 16. The surface portion 22 extends along the wall surface 16 from the first surface 13 to the second surface 14. The surface portion 22 may be in contact with a seed layer 201.

[0201] The surface portion 22 may include an end surface 221 that is parallel to the first surface 13. The end surface 221 may be located on the same plane as the first surface 13.

[0202] The surface portion 22 may include an end surface 222 that is parallel to the second surface 14. The end surface 222 may be located on the same plane as the second surface 14.

[0203] 19, the surface portion 22 includes a boundary 223. The boundary 223 is a boundary between the surface portion 22 and the closed portion 23, the first portion 24, and the second portion 25.

[0204] FIG. 20 is a cross-sectional view showing an example of the dimensions of the through electrode 20 of this modified example.

[0205] 20 , the symbol T6 denotes the thickness of the surface portion 22. The thickness T6 of the surface portion 22 is determined at a position that is a distance S3 away from the first surface 13 in the thickness direction of the substrate 12. The distance S3 is 50 μm. The thickness T6 is measured in the planar direction of the first surface 13.

[0206] The thickness T6 is, for example, 2.0 μm or more, or may be 4.0 μm or more, or 7.0 μm or more. The thickness T6 is, for example, 15.0 μm or less, or may be 12.0 μm or less, or may be 10.0 μm or less.

[0207] The ratio T6 / T3 of the thickness T6 of the surface portion 22 to the thickness T3 of the first portion 24 is, for example, 0.5 or more, or may be 0.7 or more, or may be 0.9 or more. T6 / T3 is, for example, 2.0 or less, or may be 1.5 or less, or may be 1.1 or less.

[0208] A method for forming the through electrode 20 of this modified example will be described.

[0209] 7 in the first embodiment, the seed layer forming step is performed. Subsequently, the closing plating step is performed. In this modification, the closing plating step includes a first plating step and a second plating step.

[0210] In the first plating step, a surface portion 22 of the closing electrode 21 is formed. FIG. 21 is a cross-sectional view showing an example of the first plating step. In the first plating step, the substrate 12 on which a seed layer 201 is formed may be immersed in a plating solution. By passing a current through the seed layer 201, a plating layer 202 is deposited on the seed layer 201, as shown in FIG. 21. The plating layer 202 formed in the first plating step is also referred to as a surface plating layer 202. The plating solution used in the first plating step is also referred to as a first plating solution.

[0211] The first plating solution may contain an additive. The concentration of the additive in the first plating solution is also referred to as a first concentration. In the first plating step, the first concentration is controlled so that the surface plating layer 202 grows appropriately in the normal direction of the wall surface 16. The surface plating layer 202 constitutes the surface portion 22.

[0212] The additives of the first plating solution may include a suppressor, an accelerator, etc., similar to the additives of the second plating solution described above. The types of additives of the first plating solution may be the same as the types of additives of the second plating solution.

[0213] The first concentration of the additive in the first plating solution may be lower than the second concentration of the additive in the second plating solution. As a result, in the first plating step, the surface plating layer 202 can be properly grown in the normal direction of the wall surface 16. As shown in FIG. 21 , the first plating step is completed before the surface plating layer 202 closes the thinned portion 163.

[0214] In the second plating step, the closing portion 23, the first portion 24, and the second portion 25 are formed using the second plating solution described above. FIG. 22 is a cross-sectional view showing an example of the second plating step. In the second plating step, the substrate 12 on which the seed layer 201 and the surface plating layer 202 have been formed may be immersed in the second plating solution. By passing a current through the seed layer 201 and the surface plating layer 202, a closing plating layer 203 is deposited on the surface plating layer 202, as shown in FIG. 22. The second plating step is performed until the closing plating layer 203 closes the minimum portion 163.

[0215] Subsequently, a filling plating process is performed as in the case of the first embodiment described above. Subsequently, a polishing process may be performed as in the case of the first embodiment described above. By forming the through electrodes 20 in the through holes 15, the through electrodes 20 shown in FIG. 19 are obtained.

[0216] In this modification, the surface portion 22 of the closing electrode 21 is formed by a first plating process, and the closing portion 23, first portion 24, and second portion 25 of the closing electrode 21 are formed by a second plating process. The conditions for the first plating process are different from those for the second plating process. For example, the concentration of the additive in the second plating solution is higher than the concentration of the additive in the first plating solution. In this case, growth of the closing plating layer 203 in the normal direction of the wall surface 16 is suppressed in the second plating process. As a result, for example, in the second plating process after the minimum portion 163 is closed by the closing portion 23, the closing portion 23 can grow preferentially in the thickness direction of the substrate 12. Therefore, for example, the thickness T5 of the closing portion 23 can be increased while suppressing an increase in the thickness T3 of the first portion 24. As a result, the relationship between the dimension W1 of the end surface 271 of the first filling electrode 27 formed inside the first portion 24 and the distance K1 is appropriately adjusted. Similarly, the relationship between the dimension W2 of end face 281 of second filling electrode 28 formed inside second portion 25 and distance K2 is appropriately adjusted. Therefore, the occurrence of defects such as voids in first filling electrode 27 and second filling electrode 28 is suppressed.

[0217] 23 is a cross-sectional view showing a through electrode substrate 10 in a fourth modified example. The plating layer constituting the through electrode 20 may extend continuously onto the first surface 13. For example, the closing plating layer 203 and the filling plating layer 204 constituting the through electrode 20 may extend continuously onto the first surface 13. The seed layer 201 may also extend continuously onto the first surface 13. In this case, the first conductive layer 35 located on the first surface 13 may include the seed layer 201, the closing plating layer 203, and the filling plating layer 204. This first conductive layer 35 is necessarily connected to the first portion 24 of the closing electrode 21 and the first filling electrode 27.

[0218] Although not shown, when the through electrode 20 includes a surface portion 22, the surface plating layer 202 constituting the surface portion 22 may also extend continuously to the first surface 13. In this case, the first conductive layer 35 may include the surface plating layer 202.

[0219] 23 , the plating layer constituting the through electrode 20 may extend continuously onto the second surface 14. For example, the closing plating layer 203 and the filling plating layer 204 constituting the through electrode 20 may extend continuously onto the second surface 14. The seed layer 201 may also extend continuously onto the second surface 14. In this case, the second conductive layer 36 located on the second surface 14 may include the seed layer 201, the closing plating layer 203, and the filling plating layer 204. This second conductive layer 36 is necessarily connected to the second portion 25 of the closing electrode 21 and the second filling electrode 28.

[0220] Although not shown, when the through electrode 20 includes a surface portion 22, the surface plating layer 202 constituting the surface portion 22 may also extend continuously to the second surface 14. In this case, the second conductive layer 36 may include the surface plating layer 202.

[0221] A method for forming the through electrode substrate 10 of this modified example will be described.

[0222] In this modification, the through electrode formation process includes a seed layer formation process, a resist layer formation process, a plating process, a resist layer removal process, and a seed layer removal process. In the seed layer formation process, a seed layer 201 is formed as shown in FIG. 7 of the first embodiment described above.

[0223] 24, a resist layer forming step is carried out. In the resist layer forming step, a first resist layer 41 is formed partially on the seed layer 201 located on the first surface 13, and a second resist layer 42 is formed partially on the seed layer 201 located on the second surface 14. The first resist layer 41 and the second resist layer 42 are provided so as to cover the regions of the seed layer 201 where no plating layer is to be formed.

[0224] 25 , a plating process is carried out. In the plating process, a plating layer is formed on the seed layer 201. For example, a plating layer including a closing plating layer 203 and a filling plating layer 204 is formed on the seed layer 201. The plating layer may further include a surface plating layer 202.

[0225] 26 , a resist layer removal step is performed to remove the first resist layer 41 and the second resist layer 42. Then, a seed layer removal step is performed to remove a portion of the seed layer 201. In the seed layer removal step, as shown in FIG. 26 , the seed layer 201 that overlaps the first resist layer 41 and the second resist layer 42 in plan view is removed. In this manner, the through electrode 20, the first conductive layer 35, and the second conductive layer 36 are obtained.

[0226] (Fifth Modification) FIG. 27 is a cross-sectional view showing a through hole electrode substrate 10 in a fifth modification.

[0227] The through electrode substrate 10 may include a first-side resin layer 31 located on the first side 13. The first-side resin layer 31 may be in contact with the first side 13. The first conductive layer 35 does not have to be formed between the first side 13 and the first-side resin layer 31. Although not shown, the first conductive layer 35 may be formed on the first-side resin layer 31.

[0228] The first-side resin layer 31 includes an opening 331 penetrating the first-side resin layer 31 and an opening edge 312. The opening edge 312 defines the outline of the opening 311 in a plan view. The above-described conductive layer 37 connected to the through electrode 20 may be formed in the opening 311.

[0229] The opening end 312 may be at least partially located inside the first end 161. In this case, the first surface resin layer 31 at least partially overlaps the boundary between the wall surface 16 and the seed layer 201 or the through electrode 20 in a plan view.

[0230] Gas may be generated during the manufacturing process of the through hole electrode substrate 10. For example, gas is generated from the through hole electrode 20. The gas may be, for example, water vapor. The gas is generated, for example, during the process of heating the components of the through hole electrode substrate 10.

[0231] The gas may accumulate in gaps inside the through-hole electrode substrate 10. For example, the gas accumulates in gaps between the wall surface 16 and the through-hole electrode 20. If the gas continues to accumulate in gaps inside the through-hole electrode substrate 10, there is a concern that deformation, damage, etc. may occur inside the through-hole electrode substrate 10 due to the pressure of the gas.

[0232] In this modification, the through electrode substrate 10 includes a first-side resin layer 31 that overlaps the first end 161. The molecular structure of the resin material that constitutes the first-side resin layer 31 is larger than the molecular structure of gases such as water vapor. Gas in the gap between the wall surface 16 and the through electrode 20 passes through the first-side resin layer 31 and is released to the outside of the through electrode substrate 10. Therefore, deformation, damage, and the like inside the through electrode substrate 10 are suppressed.

[0233] The through-hole electrode substrate 10 may include a second-side resin layer 32 located on the second side 14. The second-side resin layer 32 may be in contact with the second side 14. The second conductive layer 36 does not have to be formed between the second side 14 and the second-side resin layer 32. Although not shown, the second conductive layer 36 may be formed on the second-side resin layer 32.

[0234] The second-side resin layer 32 includes an opening 321 penetrating the second-side resin layer 32 and an opening edge 322. The opening edge 322 defines the outline of the opening 321 in a plan view. The above-described conductive layer 38 connected to the through electrode 20 may be formed in the opening 321.

[0235] The opening end 322 may be at least partially located inside the second end 162. In this case, the second surface resin layer 32 at least partially overlaps the boundary between the wall surface 16 and the seed layer 201 or the through electrode 20 in a plan view. Therefore, gas in the gap between the wall surface 16 and the through electrode 20 is released to the outside of the through electrode substrate 10 through the second surface resin layer 32.

[0236] 28 is a diagram showing an example of a product in which the through electrode substrate 10 is mounted. The through electrode substrate 10 can be used in a variety of products. For example, the through electrode substrate 10 is mounted in 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, and the like.

[0237] Although several modifications to the above-described embodiment have been described, it is of course possible to combine a plurality of modifications as appropriate and apply them to the above-described embodiment.

[0238] The first embodiment will be described in more detail with reference to examples. The first embodiment is not limited to the description of the following examples, as long as it does not depart from the gist of the embodiment.

[0239] Example 1 A glass substrate having a thickness T0 of 400 μm was prepared as the substrate 12. Subsequently, a through hole 15 was formed in the substrate 12. The through hole 15 included a first end 161 having a first dimension R1, a second end 162 having a second dimension R2, and a minimum portion 163 having a minimum dimension R3. The first end 161, the second end 162, and the minimum portion 163 had a circular outline in a plan view. The first dimension R1, the second dimension R2, and the minimum dimension R3 were 50 μm, 50 μm, and 30 μm, respectively.

[0240] Next, a through electrode 20 including a seed layer 201 and a copper plating layer was formed in the through hole 15. The plating layer included a closing plating layer 203 constituting the closing electrode 21 and a filling plating layer 204 constituting the first filling electrode 27 and the second filling electrode 28. The closing electrode 21 included a closing portion 23, a first portion 24, and a second portion 25. The thickness T3 of the first portion 24 and the thickness T4 of the second portion 25 were each 10 μm. The distance from the first surface 13 to the closing portion 23 in the thickness direction of the substrate 12, i.e., the first distance K1, was 175 μm. The distance from the second surface 14 to the closing portion 23 in the thickness direction of the substrate 12, i.e., the second distance K2, was 175 μm. The thickness T5 of the closing portion 23 in the thickness direction of the substrate 12 was 50 μm.

[0241] The second plating solution for forming the closing plating layer 203 was Sphero. The third plating solution for forming the filling plating layer 204 was Copper Gleam HGX manufactured by DuPont.

[0242] [Cross-sectional image of boundary region] The cross section of the through electrode 20 in the boundary region between the closing electrode 21 and the second filling electrode 28 was observed using an STEM. FIG. 29 shows the obtained cross-sectional image. The cross-sectional image in FIG. 29 is a bright-field image. The observation conditions were as follows: STEM: Hitachi High-Technologies Corporation STEM HD-2700 model Observation magnification: 22,500 times (15,000 × 1.5) Acceleration voltage: 200 kV

[0243] A dark-field image of the cross-sectional image shown in Figure 29 is shown in Figure 30. The second boundary 212 between the closing electrode 21 and the second filling electrode 28 is more clearly visible in the dark-field image than in the bright-field image.

[0244] The rectangular region marked with the character string "Photo. 2-3" in the cross-sectional image shown in Figure 29 was observed using a STEM. Figure 31 shows the obtained cross-sectional image. The observation conditions were as follows: STEM: Hitachi High-Technologies Corporation STEM HD-2700 model Observation magnification: 45,000 times (30,000 x 1.5) Acceleration voltage: 200 kV

[0245] 31, it can be seen that the plurality of crystal grains of the second filling electrode 28 has a crystal structure different from that of the plurality of crystal grains of the closing electrode 21. Examples of the crystal structure include the average cross-sectional area of ​​the crystal grains, the shape of the crystal grains, and the direction in which the crystal grains extend.

[0246] The rectangular region marked with the character string "Photo. 2-5" in the cross-sectional image shown in Figure 29 was observed using a STEM. Figure 32 shows the obtained cross-sectional image. The observation conditions were as follows: STEM: Hitachi High-Technologies Corporation STEM HD-2700 model Observation magnification: 150,000 times (100,000 x 1.5) Acceleration voltage: 200 kV

[0247] 32, it can be seen that at least one of the plurality of crystal grains in second filler electrode 28 is a linear crystal grain. The linear crystal grain has a grain boundary including a pair of linear grain boundaries 301 that are in contact with second boundary 212 and extend parallel to each other.

[0248] The cross section of the through electrode 20 was observed using STEM in the regions of the closing electrode 21, the first filling electrode 27, and the second filling electrode 28. Figure 33 is a cross-sectional view showing the observation region of each electrode. When observing the closing electrode 21, the region F1 of the closing portion 23 including the center point 151 of the through hole 15 was observed using STEM. When observing the first filling electrode 27, the region F2 of the first filling electrode 27, which is a distance K5 from the first bottom 231 in the thickness direction of the substrate 12, was measured using STEM. The distance K5 was 100 μm. When observing the second filling electrode 28, the region F3 of the second filling electrode 28, which is a distance K6 from the second bottom 232 in the thickness direction of the substrate 12, was measured using STEM. The distance K6 was 100 μm. The observation conditions were as follows.・STEM: Hitachi High-Technologies STEM HD-2700 type ・Observation magnification: 45,000 times (30,000 x 1.5) ・Accelerating voltage: 200 kV

[0249] 34 shows a cross-sectional image obtained in region F1 of closed portion 23. The average cross-sectional area of ​​the multiple crystal grains in closed portion 23 is calculated by dividing the area of ​​the cross-sectional image by the number of crystal grains that appear in the cross-sectional image.

[0250] 35 shows a cross-sectional image obtained in region F3 of second fill electrode 28. The average cross-sectional area of ​​the grains in second fill electrode 28 is calculated by dividing the area of ​​the cross-sectional image by the number of grains appearing in the cross-sectional image.

[0251] (Second Embodiment) The second embodiment is based on Japanese Patent Application No. 2024-107734 filed on July 3, 2024, and claims priority thereto. Like the first embodiment, the second embodiment also relates to a through electrode substrate, a mounting substrate, and a method for manufacturing a through electrode substrate.

[0252] In the first example of the through electrode described in Patent Document 1, the larger the dimension of the through hole in the surface direction, the higher the allowable current of the through electrode. However, the larger the dimension of the through hole, the greater the stress generated between the conductive material filled in the through hole and the substrate.

[0253] The second embodiment aims to provide a through electrode substrate and a method for manufacturing a through electrode substrate that can effectively solve such problems.

[0254] The second embodiment relates to the following [1] to

[20] . [1] A through electrode substrate, comprising: a substrate including a first surface, a second surface located opposite to the first surface, and a through hole penetrating from the first surface to the second surface; and a through electrode located in the through hole, wherein the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a minimum portion located between the first end and the second end, wherein the through hole has a minimum dimension at the minimum portion that is the minimum value of the dimension of the through hole in a plane direction of the first surface, and the through electrode includes a closing electrode that closes the through hole at the minimum portion, a first filling electrode, and a second filling electrode, wherein the closing electrode includes a closing portion located at the minimum portion, a first portion extending along the wall surface from the closing portion to the first surface, and a second portion extending along the wall surface from the closing portion to the second surface, and the first filling electrode is located inside the first portion and between the closing portion and the first surface in a thickness direction of the substrate, A through electrode substrate, wherein the second filling electrode is located inside the second portion and between the closing portion and the second surface in the thickness direction, the closing portion of the closing electrode has a first elastic modulus, and the first filling electrode and the second filling electrode each have an elastic modulus smaller than the first elastic modulus.

[0255] [2] In the through hole electrode substrate according to [1], the closing electrode may contain copper, a copper alloy, nickel, or a nickel alloy as a main component.

[0256] [3] In the through hole electrode substrate according to [1] or [2], the first filling electrode and the second filling electrode may each contain a tin alloy as a main component.

[0257] [4] In the through electrode substrate according to [1] or [2], the first filling electrode and the second filling electrode may each include a binder resin and a plurality of conductive particles dispersed in the binder resin.

[0258] [5] In the through electrode substrate according to any one of [1] to [4], the ratio of the elastic modulus of the first fill electrode and the elastic modulus of the second fill electrode to the first elastic modulus may each be 0.50 or less.

[0259] [6] In the through electrode substrate according to any one of [1] to [5], the through electrode may have a first distance that is a maximum value of the distance from the first surface to the closed portion in a thickness direction of the substrate, and a second distance that is a maximum value of the distance from the second surface to the closed portion in a thickness direction of the substrate, and the ratio of the first distance to the thickness of the substrate may be 0.10 or more, and the ratio of the second distance to the thickness of the substrate may be 0.10 or more.

[0260] [7] In the through electrode substrate according to any one of [1] to [6], the closed electrode may include a surface portion located between the closed portion, the first portion, the second portion and the wall surface, and extending along the wall surface from the first surface to the second surface.

[0261] [8] In the through electrode substrate described in [7], the closed portion, the first portion, and the second portion may contain copper or a copper alloy as a main component, and the surface portion may contain nickel or a nickel alloy as a main component.

[0262] [9] In the through hole electrode substrate according to any one of [1] to [8], the ratio of the thickness of the substrate to the minimum dimension may be 2.5 or more and 35.0 or less.

[0263]

[10] In the through hole electrode substrate according to any one of [1] to [9], the ratio of the thickness of the closed portion to the thickness of the substrate may be 0.05 or more and 0.50 or less.

[0264]

[11] The through electrode substrate according to any one of [1] to

[10] may comprise a first conductive layer located on the first surface and connected to the first fill electrode and the first portion of the closing electrode.

[0265]

[12] The through electrode substrate according to

[11] may comprise a second conductive layer located on the second surface and connected to the second filling electrode and the second portion of the closing electrode.

[0266]

[13] The through electrode substrate according to any one of [1] to

[12] may include a first surface resin layer located on the first surface, and the first surface resin layer may overlap the first end of the wall surface in a plan view.

[0267]

[14] The through electrode substrate described in

[13] may include a second surface resin layer located on the second surface, and the second surface resin layer may overlap the second end of the wall surface in a plan view.

[0268]

[15] In the through hole electrode substrate according to any one of [1] to

[14] , the substrate may be a glass substrate.

[0269]

[16] A mounting board comprising: the through electrode substrate according to any one of [1] to

[15] ; and an element electrically connected to the through electrode of the through electrode substrate.

[0270]

[17] A method for manufacturing a through electrode substrate, comprising: a step of preparing a substrate including a first surface, a second surface located opposite to the first surface, and a through hole penetrating from the first surface to the second surface; and a through electrode forming step of forming a through electrode partially in the through hole, wherein the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a minimum portion located between the first end and the second end, and the through hole has a minimum dimension at the minimum portion that is the minimum value of the dimension of the through hole in a plane direction of the first surface, and the through electrode forming step comprises a closing plating step of forming a closing electrode that closes the through hole at the minimum portion by plating, and a filling step of forming a first filling electrode and a second filling electrode, and the closing electrode includes a closing portion located at the minimum portion, a first portion extending along the wall surface from the closing portion to the first surface, and a second portion extending along the wall surface from the closing portion to the second surface, A method for manufacturing a through electrode substrate, wherein the first filling electrode is located inside the first portion and is located between the closed portion and the first surface in the thickness direction of the substrate, the second filling electrode is located inside the second portion and is located between the closed portion and the second surface in the thickness direction, the closed portion of the closed electrode has a first elastic modulus, and the first filling electrode and the second filling electrode each have an elastic modulus smaller than the first elastic modulus.

[0271]

[18] In the method for manufacturing a through electrode substrate described in

[17] , the through electrode may have a first distance that is the maximum value of the distance from the first surface to the closed portion in the thickness direction of the substrate, and a second distance that is the maximum value of the distance from the second surface to the closed portion in the thickness direction of the substrate, and the ratio of the first distance to the thickness of the substrate may be 0.10 or more, and the ratio of the second distance to the thickness of the substrate may be 0.10 or more.

[0272]

[19] In the method for manufacturing a through-hole electrode substrate described in

[17] or

[18] , the first filling electrode and the second filling electrode may each be formed by a plating process using a material having an elastic modulus lower than the first elastic modulus.

[0273]

[20] In the method for manufacturing a through-hole electrode substrate described in

[17] or

[18] , the first filling electrode and the second filling electrode may each be formed from a conductive paste containing a binder resin and a plurality of conductive particles dispersed in the binder resin.

[0274]

[21] In the method for manufacturing a through-hole electrode substrate according to any one of

[17] to

[20] , the closing plating step may include a first plating step of forming a surface portion located between the closing portion, the first portion, and the second portion and the wall surface, and a second plating step of forming the closing portion, the first portion, and the second portion.

[0275]

[22] In the method for manufacturing a through hole electrode substrate according to any one of

[17] to

[21] , the substrate may be a glass substrate.

[0276] According to the second embodiment, the allowable current of the through electrode can be increased while reducing the stress between the conductive material filled in the through hole and the substrate.

[0277] A second embodiment will now be described. In the following description and the drawings used in the following description, parts that can be configured similarly to the first embodiment described above will be designated by the same reference numerals as those used for the corresponding parts in the first embodiment described above. Duplicate descriptions will be omitted. Furthermore, if it is clear that the effects obtained in the first embodiment described above can also be obtained in the second embodiment, the description of those effects may be omitted.

[0278] Also in the second embodiment, as shown in Fig. 1 above, the through electrode substrate 10 includes a substrate 12 and at least one through electrode 20. The substrate 12 further includes at least one through hole 15 that penetrates from the first surface 13 to the second surface 14. The through electrode 20 is located in the through hole 15. In the example shown in Fig. 1 , the substrate 12 includes a plurality of through holes 15. The through electrode substrate 10 includes a through electrode 20 that is located in each of the plurality of through holes 15. Description of the substrate 12 and the through holes 15 will be omitted.

[0279] Through electrode 20 includes a conductive material. In the second embodiment, as shown in FIG. 3 , through electrode 20 also includes at least closing electrode 21, first filling electrode 27, and second filling electrode 28. Closing electrode 21 closes through hole 15 at narrowest portion 163. First filling electrode 27 is located on first surface 13. Second filling electrode 28 is located on second surface 14.

[0280] The closing electrode 21 is a plated layer. The plated layer is a conductive layer formed by a plating method such as electrolytic plating.

[0281] First filling electrode 27 and second filling electrode 28 may be plated layers. As will be described later in a modified example, first filling electrode 27 and second filling electrode 28 may be formed of conductive paste. In the second embodiment, first filling electrode 27 and second filling electrode 28 are plated layers, as in the first embodiment. The components, dimensions, and arrangement of through hole 15, closing electrode 21, first filling electrode 27, and second filling electrode 28 are the same as in the first embodiment, so a description thereof will be omitted.

[0282] In the second embodiment, closing electrode 21, first filling electrode 27, and second filling electrode 28 are distinguished based on their mechanical properties. The mechanical properties of closing electrode 21, first filling electrode 27, and second filling electrode 28 are described below. Specifically, we focus on the elastic modulus.

[0283] The closing electrode 21 has a relatively high elastic modulus, which is also referred to as a first elastic modulus.

[0284] First fill electrode 27 and second fill electrode 28 each have a modulus of elasticity that is less than the first modulus of elasticity, which modulus of elasticity of first fill electrode 27 and second fill electrode 28 is also referred to as the second modulus of elasticity.

[0285] A thermal load may be applied to the through hole electrode substrate 10. For example, a thermal cycle test may be performed on the through hole electrode substrate 10 to evaluate the reliability of the through hole electrode substrate 10. In the thermal cycle test, the temperature of the through hole electrode substrate 10 is repeatedly increased or decreased. One thermal cycle includes a temperature increase step, a high temperature holding step, a temperature decrease step, and a low temperature holding step. The thermal cycle test includes, for example, 1,000 thermal cycles.

[0286] When the thermal expansion coefficient of the through electrode 20 differs from the thermal expansion coefficient of the substrate 12, a change in the temperature of the through electrode 20 causes expansion or contraction of the through electrode 20 relative to the substrate 12. The expansion or contraction generates stress between the substrate 12 and the through electrode 20. Stress caused by a change in temperature is also called thermal stress. When expansion or contraction occurs in the through electrode 20, it is thought that large thermal stress will be generated, for example, at the first end 161 and the second end 162 of the through hole 15.

[0287] In the second embodiment, as described above, the second elastic modulus of first filling electrode 27 and second filling electrode 28 is smaller than the first elastic modulus of closing electrode 21. First filling electrode 27 and second filling electrode 28 are more elastically deformable than closing electrode 21. Therefore, for example, first filling electrode 27 can relieve thermal stress occurring in closing portion 23 or first portion 24 of closing electrode 21. Similarly, second filling electrode 28 can relieve thermal stress occurring in closing portion 23 or second portion 25 of closing electrode 21. As a result, thermal stress occurring in first end 161, second end 162, etc. is reduced. The reduction in thermal stress suppresses the occurrence of defects such as cracks in substrate 12.

[0288] The first elastic modulus E1 of the closing electrode 21 made of the plating layer is, for example, 120.0 GPa or more, or may be 130.0 GPa or more, or 150.0 GPa or more. The first elastic modulus E1 of the closing electrode 21 made of the plating layer is, for example, 220.0 GPa or less, or may be 200.0 GPa or less, or may be 180.0 GPa or less.

[0289] The plating layer of the closing electrode 21 is configured to have a first elastic modulus E1. For example, the plating layer of the closing electrode 21 may contain copper, a copper alloy, nickel, or a nickel alloy as a main component. The plating layer of the closing electrode 21 may contain 60 atomic % or more of copper, copper alloy, nickel, or a nickel alloy.

[0290] The second elastic modulus E2 of first filling electrode 27 and second filling electrode 28 made of plating layers is, for example, 15.0 GPa or more, or may be 20.0 GPa or more, or 25.0 GPa or more. The second elastic modulus E2 of first filling electrode 27 and second filling electrode 28 made of plating layers is, for example, 50.0 GPa or less, or may be 40.0 GPa or less, or may be 30.0 GPa or less.

[0291] The plating layers of first filling electrode 27 and second filling electrode 28 are configured to have a second elastic modulus E2. For example, the plating layers of first filling electrode 27 and second filling electrode 28 may each contain tin or a tin alloy as a main component. The plating layers of first filling electrode 27 and second filling electrode 28 may each contain 60 atomic % or more of tin or a tin alloy. Examples of tin alloys include a tin-silver alloy, a tin-bismuth alloy, and a tin-lead alloy.

[0292] The ratio E2 / E1 of the second elastic modulus E2 to the first elastic modulus E1 is, for example, 0.50 or less, or may be 0.40 or less, or may be 0.30 or less, and may be, for example, 0.10 or more, or may be 0.15 or more, or may be 0.20 or more.

[0293] The second elastic modulus E2 of first filling electrode 27 and second filling electrode 28 may be less than the elastic modulus of substrate 12. The elastic modulus of substrate 12 is also referred to as the substrate elastic modulus. When second elastic modulus E2 is less than the substrate elastic modulus, stress in closing electrode 21 is more likely to be relieved by first filling electrode 27 or second filling electrode 28.

[0294] The ratio E2 / E4 of the second elastic modulus E2 to the substrate elastic modulus E4 is, for example, 0.95 or less, or may be 0.90 or less, or may be 0.80 or less, and is, for example, 0.20 or more, or may be 0.30 or more, or may be 0.40 or more.

[0295] A method for measuring the elastic modulus will now be described. Figure 36 is a diagram showing the positions at which the elastic modulus is measured for the closing electrode 21, the first filling electrode 27, and the second filling electrode 28.

[0296] The first elastic modulus E1 of the closing electrode 21 is measured at the closing portion 23. Specifically, the first elastic modulus E1 is measured at the closing portion 23 located at the center point 151 of the through-hole 15.

[0297] Second elastic modulus E2 of first filling electrode 27 is measured at first measurement point 152 of first filling electrode 27. First measurement point 152 is spaced a distance K5 from first bottom portion 231 in the thickness direction of substrate 12. Distance K5 is 100 μm.

[0298] The second elastic modulus E2 of second filling electrode 28 is measured at second measurement point 153 of second filling electrode 28. Second measurement point 153 is a distance K6 away from second bottom portion 232 in the thickness direction of substrate 12. Distance K6 is 100 μm.

[0299] A method for calculating the elastic modulus by nanoindentation testing will be described with reference to Figures 37 to 40. Figure 37 is a diagram showing an indenter 70 used in nanoindentation testing. The indenter 70 includes a pyramidal surface with an apex angle of 115°.

[0300] In the nanoindentation test, an indenter 70 attached to a transducer is pressed into the surface of an object placed on a stage while applying a load with the transducer. The object includes a through electrode 20 cut along a cutting plane that passes through the center point 151 of the through hole 15 and is perpendicular to the first surface 13.

[0301] Figure 38 is a cross-sectional view showing a state in which an indenter 70 is being pressed into an object 75. The surface of the object 75 in the state in which the indenter 70 is pressed is also referred to as a deformed surface 76. Thereafter, the indenter 70 is removed from the object 75 by moving the indenter 70 in the direction opposite to the pressing direction. Figure 39 is a cross-sectional view showing the object 75 after the indenter 70 has been removed. The surface of the object 75 after the indenter 70 has been removed is also referred to as a restored surface 77. In Figure 39, the deformed surface 76 is indicated by a dotted line.

[0302] 40 is a graph showing the relationship between the indentation depth h of the indenter 70 and the load L of the indenter 70. The load L increases along a quadratic function curve A as the indentation depth h of the indenter 70 increases. Curve A represents both the elastic deformation and the plastic deformation of the object 75. When the indentation is completed, the indentation depth h of the indenter 70 reaches a maximum value h ｍａｘ The load L is also the maximum value L ｍａｘ This becomes:

[0303] After the indenter 70 has been pressed down, the indenter 70 is moved in the direction opposite to the pressing direction. As a result, as shown in FIG. 40, the load L decreases along a quadratic curve B that is steeper than the curve A. Furthermore, due to elastic recovery caused by the unloading of the indenter 70, the surface of the object 75 is deformed from a deformed surface 76 to a restored surface 77. ｆ represents the depth of the recess formed in the restoration surface 77.

[0304] In the nanoindentation test, the reduced elastic modulus E of the indentation contact ｒ is calculated by the following formula: ｒ = π １ / ２ / 2CA ｐ １ / ２ (1) In formula (1), C is the maximum value of the load L ｍａｘ The slope of the tangent to the curve B at ｐ is the projected area where the indenter 70 and the object 75 are in contact.

[0305] A in Equation (1) ｐ can be calculated by the following formula: ｐ = 23.96 × {h ｍａｘ−ε(h ｍａｘ -h Ｃ )} (2) In the formula (2), ε is a correction coefficient due to the geometric shape of the indenter 70. When the indenter 70 is a diamond Vickers indenter, ε is 0.75. Ｃ is the maximum value of the load L ｍａｘ 40. The intersection point is the point where the tangent to the curve B intersects with the horizontal axis of FIG.

[0306] Reduced Elastic Modulus E ｒ Based on this, the indentation elastic modulus E of the object 75 ＩＴ is calculated by the following formula: ＩＴ = {1-(V Ｓ ) ２} / [(1 / E ｒ )-{1-(V ｉ ) ２} / E ｉ ] (3) In formula (3), V Ｓ is the Poisson's ratio of the object 75. ｉ is the Poisson's ratio of the indenter 70. ｉ is the elastic modulus of the indenter 70.

[0307] The composition of each component of the through electrode 20 is calculated by the XPS method.

[0308] A sample for analysis is obtained by cutting the through hole electrode substrate 10 along a cutting plane that passes through the center point 151 of the through hole 15 and is perpendicular to the first surface 13. In a composition analysis of the closed portion 23, a region of the closed portion 23 including the center point 151 of the through hole 15 is measured by the XPS method. In a composition analysis of the first filling electrode 27, a region of the first filling electrode 27 that is a distance K5 from the first bottom 231 in the thickness direction of the substrate 12 is measured by the XPS method. The distance K5 is 100 μm. In a composition analysis of the second filling electrode 28, a region of the second filling electrode 28 that is a distance K6 from the second bottom 232 in the thickness direction of the substrate 12 is measured by the XPS method. The distance K6 is 100 μm.

[0309] The XPS settings for composition analysis were as follows: Incident X-ray: Mg Kα, hν = 1253.6 eV X-ray output: 10 kV, 20 mA (200 W) X-ray incident angle: 45° Photoelectron acceptance angle: 90° Measurement area: 100 μmφ Peak shift correction: Corrected so that the CC peak in the C1s peak is 285.0 eV Charge neutralization: Not performed Waveform separation of narrow peaks: Performed using the GL function (a mixed function of Gaussian and Lorentzian functions) in the analysis software provided with the instrument Etching ions: Ar gas cluster ion beam (Ar-G CIB) Etching ion acceleration voltage: 5.0 kV

[0310] The numerical ranges of the dimensions of the components of through electrode 20 may be the same as the numerical ranges described with reference to Figure 4A in the first embodiment described above. When closing electrode 21, first filling electrode 27, and second filling electrode 28 are plating layers, the cross-sectional structures of closing electrode 21, first filling electrode 27, and second filling electrode 28 may be the same as the cross-sectional structures described with reference to Figure 5 in the first embodiment described above. For example, closing electrode 21 may include a plurality of first crystal grains 29, and first filling electrode 27 and second filling electrode 28 may include a plurality of second crystal grains 30.

[0311] (Method for Manufacturing the Through Electrode Substrate) An example of a method for manufacturing the through electrode substrate 10 will be described.

[0312] (Through-Hole Forming Step) The substrate 12 is prepared. Then, the through-holes 15 are formed in the substrate 12 in the same manner as in the first embodiment.

[0313] (Through electrode forming process) Subsequently, a through electrode forming process is performed to form through electrodes 20 in through holes 15. The through electrode forming process includes a seed layer forming process, a closing plating process, and a filling process. In the closing plating process, the closing electrode 21 is formed. In the filling process, the first filling electrode 27 and the second filling electrode 28 are formed. In the second embodiment, the first filling electrode 27 and the second filling electrode 28 are formed by a plating process. The plating process for forming the first filling electrode 27 and the second filling electrode 28 is also referred to as a filling plating process.

[0314] 7 of the first embodiment, the seed layer 201 is formed on the first surface 13, the second surface 14, and the wall surface 16 of the substrate 12. For example, the seed layer 201 is formed by sputtering.

[0315] In the closing plating step and the filling plating step, a plating layer is deposited by electrolytic plating.

[0316] In the closed plating process, the substrate 12 on which the seed layer 201 is formed may be immersed in a plating solution, as in the case of the first embodiment described above. By passing a current through the seed layer 201, a plating layer 203 is deposited on the seed layer 201, as shown in FIGS. 8 and 9 described above. The plating layer 203 formed in the closed plating process is also referred to as the closed plating layer 203. The plating solution used to form the closed portion 23, the first portion 24, and the second portion 25 in the closed plating process is also referred to as the second plating solution.

[0317] The second plating solution contains ions of the metal or alloy that is the main component of the closing plating layer 203. For example, if the main component of the closing plating layer 203 is copper, the second plating solution contains copper ions.

[0318] The second plating solution may contain an additive, as in the first embodiment. As in the first embodiment, the type and concentration of the additive determine, for example, the direction in which the growth of the closed plating layer 203 occurs preferentially. The concentration of the additive in the second plating solution is also referred to as the second concentration.

[0319] In the closing plating step, by setting the second concentration to a low value, it is possible to achieve appropriate growth of the closing plating layer 203 in the normal direction of the wall surface 16 of the through hole 15 .

[0320] The through hole 15 of the substrate 12 includes a minimum portion 163. As the growth of the closing plating layer 203 progresses, the closing plating layers 203 formed along the circumferential direction of the through hole 15 in the minimum portion 163 are connected to each other, as in the case of the first embodiment described above. That is, as shown in FIG. 9 , the through hole 15 is closed by the closing plating layer 203 in the minimum portion 163. That is, a closing portion 23 is formed. The closing plating process results in a closing electrode 21 including the closing portion 23, the first portion 24, and the second portion 25.

[0321] The time and current density of the closing plating process are adjusted to achieve the above-mentioned numerical ranges for the first distance K1, the second distance K2, the thickness T5 of the closing portion 23, etc. For example, the closing plating process is carried out so that the ratio of the thickness T5 of the closing portion 23 to the thickness T0 of the substrate 12 falls within the above-mentioned numerical ranges.

[0322] In the filling plating process, as in the case of the first embodiment described above, the substrate 12 on which the seed layer 201 and the closing plating layer 203 are formed may be immersed in a plating solution different from the second plating solution described above. By passing a current through the seed layer 201 and the closing plating layer 203, a plating layer 204 is deposited on the closing plating layer 203, as shown in Figures 10 and 11 described above. The plating layer 204 formed in the filling plating process is also referred to as the filling plating layer 204. The plating solution used in the filling plating process is also referred to as the third plating solution.

[0323] The third plating solution contains ions of the metal or alloy that is the main component of the filled plating layer 204. For example, if the main component of the filled plating layer 204 is a tin-silver alloy, the third plating solution contains tin ions and silver ions.

[0324] The third plating solution may contain an additive, as in the first embodiment. As in the first embodiment, the type and concentration of the additive determine, for example, the direction in which the growth of the fill plating layer 204 preferentially occurs. The concentration of the additive in the third plating solution is also referred to as the third concentration.

[0325] The third concentration of the additive in the third plating solution may be higher than the second concentration of the additive in the second plating solution, so that, as in the first embodiment, the fill-plating step allows the fill-plated layer 204 to grow preferentially in the thickness direction of the substrate 12.

[0326] The filling plating process may be performed until the growth of filling plating layer 204 reaches the position of first surface 13 in the thickness direction of substrate 12. Filling plating layer 204 formed inside first portion 24 constitutes first filling electrode 27.

[0327] The filling plating process may be performed until the growth of filling plating layer 204 reaches the position of second surface 14 in the thickness direction of substrate 12. Filling plating layer 204 formed inside second portion 25 constitutes second filling electrode 28.

[0328] Subsequently, a polishing step may be performed in the same manner as in the first embodiment described above. The polishing step may include at least one of a first polishing step and a second polishing step.

[0329] The first polishing step forms end face 241 on first portion 24 and end face 271 on first filling electrode 27. The second polishing step forms end face 251 on second portion 25 and end face 281 on second filling electrode 28.

[0330] As shown in FIG. 12 above, the through electrode 20 is formed in the through hole 15, thereby obtaining the through electrode substrate 10.

[0331] In the through electrode substrate 10 of the second embodiment, the through electrodes 20 are filled over almost the entire area of ​​the through holes 15. Therefore, the allowable current of the through electrodes 20 is increased compared to when the through electrodes 20 are formed only in a part of the through holes 15. For example, the through electrodes 20 of this embodiment have a higher allowable current than when the through holes 15 are filled not only with the through electrodes 20 but also with a resin material.

[0332] In the second embodiment, the through electrode 20 includes a closing electrode 21, a first filling electrode 27, and a second filling electrode 28. The first filling electrode 27 and the second filling electrode 28 have a second elastic modulus that is smaller than the first elastic modulus of the closing electrode 21. The first filling electrode 27 and the second filling electrode 28 can relieve thermal stress that occurs in the closing electrode 21. The reduction in thermal stress suppresses the occurrence of defects such as cracks in the substrate 12.

[0333] The advantages of the manufacturing method of the second embodiment will be explained based on the difference from the first comparative embodiment. In the first comparative embodiment, the through electrode 20 is almost entirely formed by a plating process using plating to form the closing electrode 21.

[0334] 41 and 42 are cross-sectional views showing an example of a plating process in the fourth comparative embodiment. In the fourth comparative embodiment, after the closing portion 23 is formed in the thinnest portion 163, the plating process is continued without changing the plating solution. As shown in FIG. 18 , almost the entire through hole 15 is filled with the closing plating layer 203.

[0335] If the thermal expansion coefficient of the closing plating layer 203 differs from the thermal expansion coefficient of the substrate 12, a change in the temperature of the closing plating layer 203 will cause the closing plating layer 203 to expand or contract relative to the substrate 12. The expansion or contraction will cause thermal stress between the substrate 12 and the closing plating layer 203. In the fourth comparative example, the expansion or contraction of the closing plating layer 203 will mostly affect the substrate 12. As a result, it is conceivable that large thermal stress will occur, for example, at the first end 161 and the second end 162 of the substrate 12.

[0336] On the other hand, in the second embodiment, the through electrode 20 includes a first filling electrode 27 and a second filling electrode 28 formed by a filling plating layer 204 in addition to the closing electrode 21 formed by the closing plating layer 203. The second elastic modulus of the filling plating layer 204 is smaller than the first elastic modulus of the closing plating layer 203. The filling plating layer 204 can suppress the influence of the expansion or contraction of the closing plating layer 203 on the substrate 12. As a result, thermal stress occurring at the first end 161, the second end 162, etc. of the substrate 12 is reduced. The reduction in thermal stress suppresses the occurrence of defects such as cracks in the substrate 12.

[0337] The advantages of the through electrode substrate 10 of the second embodiment will be described based on the differences from the second and third comparative embodiments described above.

[0338] In the second comparative example, as shown in FIG. 15 described above, the size of the through-hole 15 in the planar direction of the first surface 13 is constant regardless of the position of the through-hole 15 in the thickness direction.

[0339] In the second comparative example, the larger the dimension of the through hole 15 in the planar direction of the first surface 13, the higher the allowable current of the through electrode 20. However, the larger the dimension of the through hole 15, the greater the thermal stress generated between the through electrode 20 and the substrate 12.

[0340] When the size of the through hole 15 is limited, the thermal stress is suppressed. However, when the size of the through hole 15 is limited, the allowable current of the through electrode 20 cannot be increased sufficiently.

[0341] 16 , in the third comparative embodiment, similar to the second comparative embodiment, the through electrode 20 is made of a conductive material that fills the entire area of ​​the through hole 15. In the third comparative embodiment, the dimension of the through hole 15 monotonically decreases from the first surface 13 toward the second surface 14. Therefore, the second dimension R2 is smaller than the first dimension R1.

[0342] In the third comparative example, as in the second comparative example, the larger the first dimension R1, the larger the thermal stress generated between the through electrode 20 and the substrate 12. On the other hand, if the first dimension R1 is limited, the allowable current of the through electrode 20 cannot be sufficiently increased.

[0343] Consider a case where the plating process of the third comparative embodiment includes a closing plating process and a filling plating process, similar to the second embodiment. In the closing plating process, a plating layer is formed on the second surface 14 to close the through hole 15. In the filling plating process, a plating layer is formed in the space of the through hole 15 where the second surface 14 is closed. The elastic modulus of the plating layer formed by the filling plating process is smaller than the elastic modulus of the plating layer formed by the closing plating process. Therefore, the thermal stress of the plating layer formed by the closing plating process is alleviated. However, in the third comparative embodiment, the plating layer formed by the closing plating process closes the through hole 15 on the second surface 14. Therefore, the thermal stress occurring at the second end 162 is difficult to reduce.

[0344] In the second embodiment, the closing portion 23 of the closing electrode 21 is located at the narrowest portion 163 of the through hole 15. Therefore, the thermal stress generated at the second end 162 is reduced compared to the third comparative embodiment. Therefore, in the second embodiment, the occurrence of defects such as cracks at the second end 162 is suppressed compared to the third comparative embodiment.

[0345] The second embodiment described above can be modified in various ways. Modifications will be described below with reference to the drawings as necessary. In the following description and the drawings used in the following description, parts that can be configured similarly to the second embodiment described above will be designated by the same reference numerals as those used for the corresponding parts in the second embodiment described above. Duplicate descriptions will be omitted. Furthermore, if it is clear that the effects obtained in the second embodiment described above can also be obtained in the modification, the description may be omitted.

[0346] (First Modification) As in the first modification of the first embodiment, as shown in the above-mentioned FIG. 17 , the through electrode substrate 10 may have a first conductive layer 35 located on the first surface 13.

[0347] As in the first modified example of the first embodiment, the through-hole electrode substrate 10 may have a second conductive layer 36 located on the second surface 14, as shown in Figure 17 above.

[0348] (Second Modification) As in the first modification of the first embodiment, as shown in the above-mentioned Figure 18, the through electrode substrate 10 may have a first surface resin layer 31 located on the first surface 13.

[0349] As in the first modified example of the first embodiment, the through-hole electrode substrate 10 may have a second surface resin layer 32 located on the second surface 14, as shown in Figure 18 above.

[0350] 43 is a cross-sectional view showing a through electrode 20 in a third modification. First filler electrode 27 and second filler electrode 28 may each include binder resin 206 and a plurality of conductive particles 207 dispersed in binder resin 206.

[0351] The binder resin 206 may contain an organic resin, such as an epoxy resin, etc. The conductive particles 207 may contain a metal such as copper, silver, or tin, or an alloy using any of these metals.

[0352] In this modified example, the second elastic modulus of first filling electrode 27 and second filling electrode 28 is determined based on the elastic modulus of binder resin 206, the elastic modulus of conductive particles 207, the volume ratio of conductive particles 207 to binder resin 206, etc.

[0353] The second elastic modulus E2 of first filled electrode 27 and second filled electrode 28 made of binder resin 206 and conductive particles 207 is, for example, 15.0 GPa or more, or may be 20.0 GPa or more, or 25.0 GPa or more. The second elastic modulus E2 of first filled electrode 27 and second filled electrode 28 made of binder resin 206 and conductive particles 207 is, for example, 100.0 GPa or less, or may be 80.0 GPa or less, or may be 60.0 GPa or less.

[0354] In the filling step of the manufacturing method of the through hole electrode substrate 10 of this modified example, the first filling electrode 27 and the second filling electrode 28 are each formed from a conductive paste. Specifically, after the closed plating step, a step of filling the first space SP1 and the second space SP2 with the conductive paste is performed. The conductive paste includes a binder resin 206 and a plurality of conductive particles 207 dispersed in the binder resin 206. After the conductive paste is filled into the first space SP1 and the second space SP2, a step of heating the conductive paste may be performed.

[0355] In this modification, as in the second embodiment described above, the second elastic modulus E2 of first filling electrode 27 and second filling electrode 28 is smaller than the first elastic modulus E1 of closing electrode 21. First filling electrode 27 and second filling electrode 28 can prevent the expansion or contraction of closing electrode 21 from affecting substrate 12. As a result, thermal stress occurring at first end 161, second end 162, etc. of substrate 12 is reduced. The reduction in thermal stress prevents defects such as cracks from occurring in substrate 12.

[0356] (Fourth Variant) As in the third variant of the first embodiment, as shown in the above-mentioned FIG. 19 , the closing electrode 21 may include a surface portion 22 located between the closing portion 23, the first portion 24, and the second portion 25 and the wall surface 16.

[0357] As in the third modified example of the first embodiment, the surface portion 22 has a thickness T6 as shown in Fig. 20. The numerical ranges of the thickness T6 and the ratio T6 / T3 of the surface portion 22 may be the same as the numerical ranges described in the third modified example of the first embodiment.

[0358] The surface portion 22 may have a modulus of elasticity greater than the first modulus of elasticity E1 of the closing portion 23, the first portion 24, and the second portion 25 of the closing electrode 21. The modulus of elasticity of the surface portion 22 is also referred to as the surface modulus of elasticity.

[0359] The surface elastic modulus E3 is, for example, 150.0 GPa or more, or may be 160.0 GPa or more, or 170.0 GPa or more. The surface elastic modulus E3 is, for example, 240.0 GPa or less, or may be 220.0 GPa or less, or may be 200.0 GPa or less.

[0360] The ratio E3 / E1 of the surface elastic modulus E3 to the first elastic modulus E1 is, for example, 1.10 or more, or may be 1.30 or more, or may be 1.50 or more. E2 / E1 is, for example, 2.50 or less, or may be 2.00 or less, or may be 1.70 or less.

[0361] The surface portion 22 is configured to have a surface elastic modulus E3. For example, the surface portion 22 may contain nickel or a nickel alloy as a main component. The surface portion 22 may contain 60 atomic % or more of nickel or a nickel alloy. In this case, the closing portion 23, the first portion 24, and the second portion 25 may contain copper or a copper alloy as a main component. The closing portion 23, the first portion 24, and the second portion 25 may contain 60 atomic % or more of copper or a copper alloy.

[0362] A method for forming the through electrode 20 of this modified example will be described.

[0363] 7 in the first embodiment, the seed layer forming step is performed. Subsequently, the closing plating step is performed. In this modification, the closing plating step includes a first plating step and a second plating step.

[0364] In the first plating step, the surface portion 22 of the closing electrode 21 is formed. In the first plating step, the substrate 12 on which the seed layer 201 is formed may be immersed in a plating solution. By passing a current through the seed layer 201, a plating layer 202 is deposited on the seed layer 201 as shown in FIG. 21 described above, as in the third modified example of the first embodiment. The plating layer 202 formed in the first plating step is also referred to as a surface plating layer 202. The plating solution used in the first plating step is also referred to as a first plating solution.

[0365] The first plating solution contains ions of the metal or alloy that is the main component of the surface plating layer 202. For example, if the main component of the surface plating layer 202 is nickel, the first plating solution contains nickel ions.

[0366] In the second plating step, the closing portion 23, the first portion 24, and the second portion 25 are formed using the second plating solution described above. In the second plating step, the substrate 12 on which the seed layer 201 and the surface plating layer 202 have been formed may be immersed in the second plating solution. By passing a current through the seed layer 201 and the surface plating layer 202, the closing plating layer 203 is deposited on the surface plating layer 202, as shown in FIG. 22 described above, as in the third modified example of the first embodiment. The second plating step is performed until the closing plating layer 203 closes the minimum portion 163.

[0367] The second plating solution contains ions of the metal or alloy that is the main component of the closing plating layer 203. For example, if the main component of the closing plating layer 203 is copper, the second plating solution contains copper ions.

[0368] Subsequently, a filling step is performed to form first filling electrode 27 and second filling electrode 28 .

[0369] The filling step may include a filling plating step of forming the filling plated layer 204 using the third plating solution described above. The third plating solution contains ions of a metal or alloy that is the main component of the filling plated layer 204. For example, when the main component of the filling plated layer 204 is a tin-silver alloy, the third plating solution contains tin ions and silver ions.

[0370] The filling step may include forming first fill electrode 27 and second fill electrode 28 using a conductive paste.

[0371] After the filling step, a polishing step may be carried out as in the case of the above-described embodiment. By forming the through electrodes 20 in the through holes 15, the above-described through electrodes 20 shown in FIG.

[0372] In this modification, the second elastic modulus E2 of first filling electrode 27 and second filling electrode 28 is smaller than the first elastic modulus E1 of closed portion 23, first portion 24, and second portion 25, which is smaller than the surface elastic modulus E3 of surface portion 22. Therefore, at first surface 13, surface portion 22, first portion 24, and first filling electrode 27 are arranged such that the elastic modulus decreases toward the center. This elastic modulus distribution reduces thermal stress at first edge 161 of substrate 12. Similarly, at second surface 14, surface portion 22, second portion 25, and second filling electrode 28 are arranged such that the elastic modulus decreases toward the center. This elastic modulus distribution reduces thermal stress at second edge 162 of substrate 12. This reduction in thermal stress prevents defects such as cracks from occurring in substrate 12.

[0373] (Fifth Modification) As in the fourth modification of the first embodiment, as shown in FIG. 23 above, the plating layer that constitutes the through electrode 20 may extend continuously onto the first surface 13.

[0374] As in the fourth variant of the first embodiment, when the through electrode 20 includes a surface portion 22, the surface plating layer 202 constituting the surface portion 22 may also extend continuously to the first surface 13.

[0375] As in the fourth modification of the first embodiment, the plating layer constituting the through electrode 20 may extend continuously onto the second surface 14 as shown in FIG. 23 described above.

[0376] As in the fourth variant of the first embodiment, when the through electrode 20 includes a surface portion 22, the surface plating layer 202 constituting the surface portion 22 may also extend continuously to the second surface 14.

[0377] A method for forming the through electrode substrate 10 of this modified example will be described.

[0378] In this modification, the through electrode formation process includes a seed layer formation process, a resist layer formation process, a plating process, a resist layer removal process, and a seed layer removal process. In the seed layer formation process, a seed layer 201 is formed as shown in FIG. 7 of the first embodiment described above.

[0379] Subsequently, as in the fourth modification of the first embodiment, the resist layer forming step is carried out as shown in FIG. 24 described above.

[0380] Subsequently, as in the fourth modification of the first embodiment, a plating step is carried out as shown in FIG. 25 described above.

[0381] Next, as in the case of the fourth modified example of the first embodiment, a resist layer removal step is performed to remove the first resist layer 41 and the second resist layer 42, as shown in Fig. 26 described above. Next, a seed layer removal step is performed to remove a portion of the seed layer 201. In the seed layer removal step, as shown in Fig. 26 described above, the seed layer 201 that overlaps the first resist layer 41 and the second resist layer 42 in plan view is removed. In this manner, the through electrode 20, the first conductive layer 35, and the second conductive layer 36 are obtained.

[0382] Although not shown, first fill electrode 27 and second fill electrode 28 may be formed of a conductive paste. First conductive layer 35 and second conductive layer 36 may or may not include a layer of conductive paste.

[0383] (Sixth Modification) As in the fifth modification of the first embodiment, as shown in the above-mentioned FIG. 27 , the through-hole electrode substrate 10 may include a first surface resin layer 31 located on the first surface 13 .

[0384] In this modification, the through electrode substrate 10 includes a first-side resin layer 31 that overlaps the first end 161. The molecular structure of the resin material that constitutes the first-side resin layer 31 is larger than the molecular structure of gases such as water vapor. Gas in the gap between the wall surface 16 and the through electrode 20 passes through the first-side resin layer 31 and is released to the outside of the through electrode substrate 10. Therefore, as in the case of the fifth modification of the first embodiment, deformation, damage, and the like inside the through electrode substrate 10 are suppressed.

[0385] As in the fifth modification of the first embodiment, the through hole electrode substrate 10 may include a second surface resin layer 32 located on the second surface 14 .

[0386] As in the fifth modified example of the first embodiment, the opening end 322 of the second-side resin layer 32 may be at least partially located inside the second end 162. In this case, the second-side resin layer 32 at least partially overlaps the boundary between the wall surface 16 and the seed layer 201 or the through-electrode 20 in a plan view. Therefore, as in the fifth modified example of the first embodiment, gas in the gap between the wall surface 16 and the through-electrode 20 is released to the outside of the through-electrode substrate 10 through the second-side resin layer 32.

[0387] As in the first embodiment, as shown in FIG. 28 above, the through hole electrode substrate 10 can be used in a variety of products.

[0388] Although several modifications of the second embodiment have been described above, it is possible to combine multiple modifications as appropriate and apply them to the above-described embodiment. The configuration of the first embodiment or its modifications may be applied to the second embodiment. For example, the closing electrode 21, the first filling electrode 27, and the second filling electrode 28 of the second embodiment may have the cross-sectional structure shown in Figure 5.

[0389] REFERENCE SIGNS LIST 10 through electrode substrate 12 substrate 13 first surface 14 second surface 15 through hole 16 wall surface 161 first end 162 second end 163 thinnest portion 17 adhesion layer 20 through electrode 201 seed layer 202 surface plating layer 203 closing plating layer 204 filling plating layer 206 binder resin 207 conductive particle 21 closing electrode 22 surface portion 23 closing portion 24 first portion 25 second portion 27 first filling electrode 28 second filling electrode 29 first crystal grain 30 second crystal grain 301 linear grain boundary 31 first surface resin layer 32 second surface resin layer

Claims

A through electrode substrate, a substrate including a first surface, a second surface located opposite to the first surface, and a through hole penetrating from the first surface to the second surface; a through electrode located in the through hole, the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a thin portion located between the first end and the second end, the through hole has a minimum dimension at the minimum portion, which is a minimum value of the dimension of the through hole in a surface direction of the first surface, the through electrode includes a closing electrode that closes the through hole at the narrowest portion, a first filling electrode, and a second filling electrode; the closed electrode includes a closed portion located at the minimum portion, a first portion extending along the wall surface from the closed portion to the first surface, and a second portion extending along the wall surface from the closed portion to the second surface, the first fill electrode is located inside the first portion and between the closing portion and the first surface in a thickness direction of the substrate; the second filling electrode is located inside the second portion and between the closing portion and the second surface in the thickness direction; the closing electrode includes a plurality of first grains; The through-hole electrode substrate, wherein the first fill electrode and the second fill electrode each include a plurality of second crystal grains having a crystal structure different from the first crystal grains. 　 the plurality of second grains of the first fill electrode and the plurality of second grains of the second fill electrode each include at least one linear grain; The through electrode substrate according to claim 1, wherein the linear crystal grains have crystal boundaries including a pair of linear grain boundaries that contact the boundary between the closing electrode and the first filling electrode or the boundary between the closing electrode and the second filling electrode and extend parallel to each other. 　 the plurality of first grains have a first average cross-sectional area; The through hole electrode substrate according to claim 1 , wherein the plurality of second crystal grains have an average cross-sectional area larger than the first average cross-sectional area. 　 The through hole electrode substrate according to claim 1 , wherein the plurality of first crystal grains have a first average crystal grain size of 50 nm or more and less than 500 nm. 　 The through hole electrode substrate according to claim 4 , wherein the plurality of second crystal grains have a second average crystal grain size of 500 nm or more and 2.0 μm or less. 　 the through electrode has a first distance that is a maximum value of a distance from the first surface to the closed portion in a thickness direction of the substrate, and a second distance that is a maximum value of a distance from the second surface to the closed portion in the thickness direction of the substrate, a ratio of the first distance to a thickness of the substrate is 0.10 or greater; The through hole electrode substrate according to claim 1 , wherein a ratio of the second distance to a thickness of the substrate is 0.10 or greater. 　 The closing electrode is located between the closing portion, the first portion, the second portion and the wall surface, and includes a surface portion extending along the wall surface from the first surface to the second surface. A through electrode substrate according to any one of claims 1 to 6. 　 The through hole electrode substrate according to claim 1 , wherein the plurality of first crystal grains and the plurality of second crystal grains each contain the same metal material as a main component. 　 the closing portion of the closing electrode has a first modulus of elasticity; The through hole electrode substrate according to claim 1 , wherein the first fill electrode and the second fill electrode each have a modulus of elasticity that is less than the first modulus of elasticity. 　 A through electrode substrate, a substrate including a first surface, a second surface located opposite to the first surface, and a through hole penetrating from the first surface to the second surface; a through electrode located in the through hole, the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a thin portion located between the first end and the second end, the through hole has a minimum dimension at the minimum portion, which is a minimum value of the dimension of the through hole in a surface direction of the first surface, the through electrode includes a closing electrode that closes the through hole at the narrowest portion, a first filling electrode, and a second filling electrode; the closed electrode includes a closed portion located at the minimum portion, a first portion extending along the wall surface from the closed portion to the first surface, and a second portion extending along the wall surface from the closed portion to the second surface, the first fill electrode is located inside the first portion and between the closing portion and the first surface in a thickness direction of the substrate; the second filling electrode is located inside the second portion and between the closing portion and the second surface in the thickness direction; the closing portion of the closing electrode has a first modulus of elasticity; The through-electrode substrate, wherein the first fill electrode and the second fill electrode each have a modulus of elasticity that is less than the first modulus of elasticity. 　 The through hole electrode substrate according to claim 10 , wherein the closing electrode contains copper, a copper alloy, nickel, or a nickel alloy as a main component. 　 The through hole electrode substrate of claim 11 , wherein the first fill electrode and the second fill electrode each contain a tin alloy as a primary component. 　 The through hole electrode substrate of claim 11 , wherein the first fill electrode and the second fill electrode each include a binder resin and a plurality of conductive particles dispersed in the binder resin. The through hole electrode substrate of claim 10 , wherein the ratio of the modulus of elasticity of the first fill electrode and the second fill electrode to the first modulus of elasticity is each 0.50 or less. 　 the through electrode has a first distance that is a maximum value of a distance from the first surface to the closed portion in a thickness direction of the substrate, and a second distance that is a maximum value of a distance from the second surface to the closed portion in the thickness direction of the substrate, a ratio of the first distance to a thickness of the substrate is 0.10 or greater; The through hole electrode substrate according to claim 10 , wherein a ratio of the second distance to a thickness of the substrate is 0.10 or greater. 　 The closing electrode is located between the closing portion, the first portion, the second portion and the wall surface, and includes a surface portion extending along the wall surface from the first surface to the second surface. A through electrode substrate according to any one of claims 10 to 15. 　 the closing portion, the first portion, and the second portion contain copper or a copper alloy as a primary component; The through-hole electrode substrate according to claim 16 , wherein the surface portion contains nickel or a nickel alloy as a main component. 　 The through hole electrode substrate according to any one of claims 1 to 6 and claims 10 to 15, wherein the ratio of the thickness of the substrate to the minimum dimension is 2.5 or more and 35.0 or less. 　 The through hole electrode substrate according to any one of claims 1 to 6 and claims 10 to 15, wherein a ratio of the thickness of the closed portion to the thickness of the substrate is 0.05 or more and 0.50 or less. 　 A through-hole electrode substrate according to any one of claims 1 to 6 and claims 10 to 15, comprising a first conductive layer located on the first surface and connected to the first filling electrode and the first portion of the closing electrode. 　 The through-hole electrode substrate of claim 20 , comprising a second conductive layer located on the second surface and connected to the second fill electrode and the second portion of the closing electrode. 　 a first-surface resin layer located on the first surface; The through electrode substrate according to any one of claims 1 to 6 and claims 10 to 15, wherein the first surface resin layer overlaps the first end of the wall surface in a plan view. 　 a second-surface resin layer located on the second surface; The through hole electrode substrate according to claim 22 , wherein the second surface resin layer overlaps the second end of the wall surface in a plan view. 　 The through-hole electrode substrate according to any one of claims 1 to 6 and claims 10 to 15, wherein the substrate is a glass substrate. 　 The through electrode substrate according to any one of claims 1 to 6 and claims 10 to 15, an element electrically connected to the through electrode of the through electrode substrate. 　 A method for manufacturing a through hole electrode substrate, providing a substrate including a first surface, a second surface opposite to the first surface, and a through hole extending from the first surface to the second surface; a through electrode forming step of partially forming a through electrode in the through hole, the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a thin portion located between the first end and the second end, the through hole has a minimum dimension at the minimum portion, which is a minimum value of the dimension of the through hole in a surface direction of the first surface, the through electrode forming step includes a step of forming a seed layer on a wall surface of the through hole, and a plating step of forming a plating layer on the seed layer, the plating step includes a closing plating step of forming a closing electrode that closes the through hole in the thinnest portion, and a filling plating step of forming a first filling electrode and a second filling electrode, the closed electrode includes a closed portion located at the minimum portion, a first portion extending along the wall surface from the closed portion to the first surface, and a second portion extending along the wall surface from the closed portion to the second surface, the first fill electrode is located inside the first portion and between the closing portion and the first surface in a thickness direction of the substrate; the second filling electrode is located inside the second portion and between the closing portion and the second surface in the thickness direction; The method for manufacturing a through hole electrode substrate, wherein the concentration of an additive contained in the plating solution used in the filling plating step is higher than the concentration of an additive contained in the plating solution used in the closing plating step. 　 A method for manufacturing a through hole electrode substrate, providing a substrate including a first surface, a second surface opposite to the first surface, and a through hole extending from the first surface to the second surface; a through electrode forming step of partially forming a through electrode in the through hole, the through hole has a wall surface including a first end connected to the first surface, a second end connected to the second surface, and a thin portion located between the first end and the second end, the through hole has a minimum dimension at the minimum portion, which is a minimum value of the dimension of the through hole in a surface direction of the first surface, the through-hole forming step includes a closing plating step of forming a closing electrode that closes the through-hole in the narrowest portion by plating, and a filling step of forming a first filling electrode and a second filling electrode; the closed electrode includes a closed portion located at the minimum portion, a first portion extending along the wall surface from the closed portion to the first surface, and a second portion extending along the wall surface from the closed portion to the second surface, the first fill electrode is located inside the first portion and between the closing portion and the first surface in a thickness direction of the substrate; the second filling electrode is located inside the second portion and between the closing portion and the second surface in the thickness direction; the closing portion of the closing electrode has a first modulus of elasticity; The method for manufacturing a through hole electrode substrate, wherein the first fill electrode and the second fill electrode each have a modulus of elasticity that is less than the first modulus of elasticity. 　 the through electrode has a first distance that is a maximum value of a distance from the first surface to the closed portion in a thickness direction of the substrate, and a second distance that is a maximum value of a distance from the second surface to the closed portion in the thickness direction of the substrate, a ratio of the first distance to a thickness of the substrate is 0.10 or greater; 28. The method for manufacturing a through hole electrode substrate according to claim 26 or 27, wherein a ratio of the second distance to a thickness of the substrate is 0.10 or more.

28. The method for manufacturing a through-hole electrode substrate according to claim 26 or 27, wherein the closing plating process includes a first plating process for forming a surface portion located between the closing portion, the first portion, the second portion and the wall surface, and a second plating process for forming the closing portion, the first portion and the second portion.

30. The method for manufacturing a through hole electrode substrate according to claim 29, wherein a concentration of the additive contained in the plating solution used in the second plating step is higher than a concentration of the additive contained in the plating solution used in the first plating step.

28. The method for manufacturing a through hole electrode substrate according to claim 26 or 27, wherein a ratio of the thickness of the substrate to the minimum dimension is 2.5 or more and 35.0 or less.

28. The method for manufacturing a through hole electrode substrate according to claim 26 or 27, wherein a ratio of a thickness of the closed portion to a thickness of the substrate is 0.05 or more and 0.50 or less.

28. The method for manufacturing a through hole electrode substrate of claim 27, wherein the first fill electrode and the second fill electrode are each formed by a plating process using a material having a modulus of elasticity lower than the first modulus of elasticity.

28. The method for manufacturing a through hole electrode substrate according to claim 27, wherein the first fill electrode and the second fill electrode are each formed from a conductive paste containing a binder resin and a plurality of conductive particles dispersed in the binder resin. 　 The method for manufacturing a through hole electrode substrate according to claim 26 or 27, wherein the substrate is a glass substrate.

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