Through-hole electrode substrate

Abstract

To provide a penetration electrode substrate capable of suppressing cracking of the penetration electrode substrate from a side surface of a through hole and formation of a gap between a through electrode and the side surface of the through hole.SOLUTION: A penetration electrode substrate according to the present disclosure includes a substrate including a first surface and a second surface and having a through hole and a through electrode positioned in the through hole, and the through hole has a narrowed portion with a minimum hole diameter. The through electrode includes a conductive filling portion formed so as to block the through hole at a position including the narrowed portion, a first surface side thin portion formed on a side surface of the through hole and extending from the conductive filling portion toward the first surface, and a second surface side thin portion formed on the side surface of the through hole and extending from the conductive filling portion toward the second surface, and the hole diameter p of the through hole in the narrowed portion is 10 μm or more and 50 μm or less, and the length f of the conductive filling portion from the first surface side toward the second surface side is 30 μm or more and 100 μm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a through electrode substrate having a through electrode. [Background technology]

[0002] A through electrode substrate includes a substrate including a first surface and a second surface, a plurality of through holes provided in the substrate, and through electrodes provided inside the through holes so as to extend from the first surface side to the second surface side of the substrate, as disclosed in Patent Document 1, for example. Such through electrode substrates have conventionally been used for a variety of purposes, and are mounted in electronic devices such as mobile phones. The through electrodes of such through electrode substrates are generally classified into a filled type (also called a filled via) in which a conductive material (typically copper) fills the entire through hole, and an unfilled type (also called a conformal via) in which a conductive material layer is provided on the side of the through hole, making it hollow.

[0003] As a method for forming a through electrode, for example, a method is known in which a seed layer is formed on the side surface of a through hole, and a plating layer is formed on the seed layer by electrolytic plating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-163986 Summary of the Invention [Problem to be solved by the invention]

[0005] LSI devices mounted on through-hole electrode substrates are becoming increasingly highly integrated, and this trend is driving demands for higher density and finer through-hole electrodes in the through-hole electrode substrates. Furthermore, as through-hole electrode substrates become more complex due to higher density, they are also being required to be highly reliable. One test for this high reliability is a heat cycle test. In a heat cycle test, for example, a through hole electrode substrate is heated from -55°C to 125°C over one hour, held at 125°C for one hour, and then cooled from 125°C to -55°C over one hour. In some tests, this heat cycle is repeated 1,000 times on a through hole electrode substrate.

[0006] However, there was a problem that the thermal stress of the heat cycle test described above caused cracks to form in the through electrode substrate from the side of the through hole, and that gaps were formed between the through electrode and the side of the through hole.

[0007] An object of the embodiments of the present disclosure is to provide a through electrode substrate that can effectively solve the above-mentioned problems. [Means for solving the problem]

[0008] A through electrode substrate according to an embodiment of the present disclosure includes a substrate including a first surface and a second surface opposite to the first surface and having a through hole provided therein, and a through electrode located in the through hole of the substrate, wherein the through hole has a narrowed portion where the hole diameter is smallest, and the through electrode has, in this order from a side surface of the through hole toward a center of the through hole, an adhesion layer, a seed layer, and a conductive layer, the adhesion layer containing one of titanium, titanium nitride, and zinc oxide, and the conductive layer containing copper, and further wherein the through electrode is formed so as to close the through hole at a position including the narrowed portion. a conductive filling portion formed on the side of the through hole and extending from the conductive filling portion toward the first surface of the substrate; a first surface side thin portion formed on the side of the through hole and extending from the conductive filling portion toward the second surface of the substrate; a second surface side thin portion formed on the side of the through hole and extending from the conductive filling portion toward the second surface of the substrate; and a second surface side connection portion formed on the second surface of the substrate, wherein the diameter p of the through hole at the narrowed portion is 10 μm or more and 50 μm or less, and the length f of the conductive filling portion from the first surface side of the substrate toward the second surface side at the center position of the through hole in a planar view is 30 μm or more and 100 μm or less.

[0009] In the through electrode substrate according to the embodiment of the present disclosure, the second surface side thin portion of the through electrode at a height position of the second surface of the substrate may have a thickness t of 5 μm or more and 15 μm or less.

[0010] In one embodiment of the through-hole electrode substrate of the present disclosure, the narrowed portion of the through-hole is located at a distance d from the first surface of the substrate toward the second surface, and the distance d may be 20 μm or more and less than 1 / 2 of the thickness g of the substrate.

[0011] In the through hole electrode substrate according to an embodiment of the present disclosure, the thickness g of the substrate may be 200 μm or more and 500 μm or less.

[0012] In a through-hole electrode substrate according to one embodiment of the present disclosure, the angle θ formed by a line connecting the edge of the narrowing portion and the edge of the opening of the through-hole on the second surface side of the substrate, on one of a pair of side surfaces that constitute the through-hole in a cross-sectional view, and a normal to the second surface of the substrate may be 1.25° or more and 6.25° or less.

[0013] In a through electrode substrate according to one embodiment of the present disclosure, an embedded resin portion may be formed from the side of the second surface of the substrate of the conductive filling portion of the through electrode in the through hole toward the second surface of the substrate.

[0014] In a through electrode substrate according to one embodiment of the present disclosure, a length fJ from the surface of the embedded resin portion on the side of the second surface of the substrate to the second surface of the substrate in a normal direction of the second surface of the substrate may be 0 μm or more and 50 μm or less.

[0015] In the through hole electrode substrate according to the embodiment of the present disclosure, the embedded resin portion may have a dielectric loss tangent of 0.003 or more and 0.02 or less at a frequency of 20 GHz.

[0016] In one embodiment of the through electrode substrate of the present disclosure, the embedded resin portion may contain an embedded resin filler, and the embedded resin filler may have a thermogravimetric change of 3% by weight or less at 250°C, a thermal expansion coefficient of 1 ppm / K or more and 5 ppm / K or less, and the embedded resin filler may be contained in an amount of 30% by volume or more and 80% by volume or less of the embedded resin portion.

[0017] In one embodiment of the through electrode substrate of the present disclosure, an insulating resin layer may be provided on the second surface side of the substrate and from the second surface side of the substrate of the embedded resin portion in the through hole toward the second surface side of the substrate.

[0018] In the through hole electrode substrate according to the embodiment of the present disclosure, the insulating resin layer may have a dielectric loss tangent of 0.001 or more and 0.01 or less at a frequency of 20 GHz.

[0019] In a through electrode substrate according to one embodiment of the present disclosure, the insulating resin layer may contain an insulating resin filler, which has a thermogravimetric change of 3% by weight or less at 250°C and a thermal expansion coefficient of 1 ppm / K or more and 5 ppm / K or less, and the insulating resin filler may be contained in an amount of more than 0% by volume and 40% by volume or less of the insulating resin layer. [Effects of the Invention]

[0020] According to an embodiment of the present disclosure, a through electrode substrate can be provided that can prevent cracks from occurring in the through electrode substrate from the side of the through hole and prevent gaps from occurring between the through electrode and the side of the through hole. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a cross-sectional view showing a main part of a through-hole electrode substrate according to an embodiment; [Figure 2] FIG. 2 is a cross-sectional view showing a through hole of the through electrode substrate shown in FIG. [Figure 3] FIG. 2 is a cross-sectional view showing the through electrode of the through electrode substrate shown in FIG. [Figure 4]FIG. 10 is a cross-sectional view showing a through hole electrode substrate according to another embodiment; [Figure 5] FIG. 10 is a cross-sectional view showing a through hole electrode substrate according to another embodiment; [Figure 6] 1 is a diagram showing an example of a manufacturing process for a through-hole electrode substrate; [Figure 7] FIG. 7 is a diagram showing an example of a manufacturing process for a through-hole electrode substrate following FIG. 6. [Figure 8] FIG. 8 is a diagram showing an example of a manufacturing process for a through-hole electrode substrate following FIG. 7. [Figure 9] FIG. 9 is a diagram showing an example of a manufacturing process of a through hole electrode substrate following FIG. 8. [Figure 10] FIG. 10 is a diagram showing an example of a manufacturing process of a through hole electrode substrate following FIG. 9. [Figure 11] 11 is a diagram showing an example of a manufacturing process of a through hole electrode substrate following FIG. 10. [Figure 12] 12 is a diagram showing an example of a manufacturing process of a through hole electrode substrate following FIG. 11. [Figure 13] 13 is a diagram showing an example of a manufacturing process of a through hole electrode substrate following FIG. 12. [Figure 14] 14 is a diagram showing an example of a manufacturing process of a through hole electrode substrate following FIG. 13. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, a through-hole electrode substrate and a manufacturing method thereof according to an embodiment of the present disclosure will be described in detail with reference to the drawings. Note that the embodiments described below are examples of embodiments of the present disclosure, and the present disclosure should not be interpreted as being limited to these embodiments. Furthermore, terms used in this specification that specify shapes, geometric conditions, and their degrees, such as "parallel" and "orthogonal," as well as values ​​of length and angle, are not limited to their strict meanings but are interpreted to include the range within which similar functions can be expected. In addition, in the drawings referred to in this embodiment, identical or similar symbols are used for identical parts or parts having similar functions, and repeated explanations may be omitted. Furthermore, the dimensional ratios in the drawings may differ from the actual ratios for convenience of explanation, and some components may be omitted from the drawings.

[0023] <Through-electrode substrate> Hereinafter, an embodiment of the present disclosure will be described. First, the configuration of a through electrode substrate 1 according to one embodiment of the present disclosure will be described with reference to Fig. 1 to Fig. 3. Here, Fig. 1 is a cross-sectional view showing a main part of the through electrode substrate 1, Fig. 2 is a cross-sectional view showing a through hole 13 provided in the through electrode substrate 1, and Fig. 3 is a cross-sectional view showing a through electrode 20 provided in the through electrode substrate 1.

[0024] As shown in Figure 1, the through electrode substrate 1 comprises a substrate 10 including a first surface 11 and a second surface 12 located opposite the first surface 11 and having a through hole 13 formed therein, and a through electrode 20 located in the through hole 13 of the substrate 10. Here, in FIG. 1, as an example, an enlarged cross-sectional view of one through electrode (through electrode 20) that the through electrode substrate 1 has is shown, but typically, the through electrode substrate 1 is provided with a plurality of through electrodes. Each component of the through hole electrode substrate 1 will be described below.

[0025] (substrate) 1 and 2, the substrate 10 includes a first surface 11 and a second surface 12 located on the opposite side of the first surface 11. The substrate 10 also has a through-hole 13 extending from the first surface 11 to the second surface 12.

[0026] The substrate 10 contains an inorganic material with a certain level of insulating properties. Since this allows for small expansion or contraction of the substrate 10 in response to temperature changes, it is preferable that the thermal expansion coefficient of the substrate 10 is small. For example, the thermal expansion coefficient of the substrate 10 is preferably 2 ppm / K or more and 8 ppm / K or less. Furthermore, in order to minimize transmission loss at high frequencies in the through-hole electrode substrate, it is preferable that the dielectric loss tangent of the substrate 10 is small. For example, the dielectric loss tangent of the substrate 10 at a frequency of 20 GHz is preferably 0.0003 or more and 0.005 or less.

[0027] For example, the substrate 10 is a glass substrate or a quartz substrate. Examples of glass used for the substrate 10 include alkali-free glass.

[0028] Alkali-free glass is glass that does not contain alkali components such as sodium or potassium. For example, alkali-free glass contains boric acid instead of alkali components. Furthermore, alkali-free glass contains alkaline earth metal oxides such as calcium oxide and barium oxide. Examples of alkali-free glass include EN-A1 manufactured by Asahi Glass Co., Ltd. and Eagle XG manufactured by Corning Co., Ltd.

[0029] The thickness g of the substrate 10 is preferably 200 μm or more and 500 μm or less. The manufacturing process of the through hole electrode substrate includes a polishing step, typically a CMP (Chemical Mechanical Polishing) step, but if the thickness g of the substrate 10 is less than 200 μm, the thin thickness results in insufficient strength and may result in breakage during the polishing step.

[0030] In addition, the manufacturing process for a through electrode substrate includes a step of forming a seed layer to form a thick through electrode by electroplating. However, if the thickness g of the substrate 10 is greater than 500 μm, the depth of the through hole will be greater than the opening, and if the seed layer is formed by sputtering, it may not be possible to form a seed layer of the required thickness deep inside the through hole, and the through electrode formed by subsequent electroplating may not be of the desired thickness.

[0031] On the other hand, when the thickness g of the substrate 10 is 200 μm or more and 500 μm or less, the above-mentioned problems do not occur and the through hole electrode substrate 1 can be obtained satisfactorily.

[0032] (Through hole) As shown in Figure 2, the through hole 13 formed in the substrate 10 has a narrowed portion 14 at a distance d from the first surface 11 of the substrate 10 toward the second surface 12, where the diameter of the through hole 13 is at its smallest.

[0033] In other words, when viewed in cross section, the side of the through hole 13 formed in the substrate 10 has a tapered first surface side portion 15 that tapers from the first surface 11 side of the substrate 10 toward the narrowed portion 14, a tapered second surface side portion 16 that tapers from the second surface 12 side of the substrate 10 toward the narrowed portion 14, and a narrowed portion 14 where the first surface side portion 15 and the second surface side portion 16 are connected.

[0034] Since the shape of the openings of through hole 13 on the first surface 11 side and second surface 12 side in a plan view is usually circular, through hole 13 can also be expressed as a shape in which two truncated cones with the same smaller-area bottom surface (upper base) are joined together at their upper bases. In this case, the joined upper base portion corresponds to narrowed portion 14.

[0035] The tapered shape mentioned above means a "taper" shape when viewed from a broad perspective, and does not necessarily mean that the side surfaces of each part in a cross-sectional view of through hole 13 as shown in FIG. 2 extend linearly. Even if the side surfaces extend in a curved shape, include a curved portion in part, or have both a linear portion and a curved portion, these shapes are included in the concept of a tapered shape as long as they are "tapered" when viewed from a broad perspective.

[0036] In the through hole 13 shown in Figure 2, the position of the narrowed portion 14 is at a distance d from the first surface 11 of the substrate 10 toward the second surface, and it is preferable that the size of this distance d is 20 μm or more and 1 / 2 or less of the thickness g of the substrate 10.

[0037] As described above, the manufacturing process of the through-hole electrode substrate includes a polishing process, typically a CMP (Chemical Mechanical Polishing) process. However, if the distance d is smaller than 20 μm, the edge of the opening of the through-hole 13 on the first surface 11 side is likely to chip during this polishing process.

[0038] Furthermore, the manufacturing process for a through electrode substrate may include a process of applying and removing a resist on the upper side of the first surface 11 of the substrate 10. However, if the distance d is greater than half the thickness g of the substrate 10, the depth of the recess in the center of the first surface 11 side of the through electrode 20 in the through electrode substrate 1 shown in Figure 1 (the recess surrounded by the thin-walled portion 20a on the first surface side of the through electrode 20 shown in Figure 3) will become large, which can easily cause problems such as abnormal resist application or insufficient resist removal resulting in the generation of foreign matter.

[0039] On the other hand, when the distance d is 20 μm or more and is 1 / 2 or less of the thickness g of the substrate 10, the above-mentioned problems do not occur, and a good through-hole electrode substrate 1 can be obtained, as in the examples described below.

[0040] Furthermore, in through-hole 13 shown in FIG. 2, the hole diameter p of through-hole 13 at narrowed portion 14 is preferably 10 μm or more and 50 μm or less.

[0041] The through hole 13 is formed by laser processing or the like, but if the hole diameter p of the through hole 13 at the narrowed portion 14 is smaller than 10 μm, the narrowed portion 14 becomes too narrow, making it difficult to form the through hole 13 in the desired shape.

[0042] Furthermore, as will be described later, the through electrode 20 of the through electrode substrate 1 shown in Figures 1 and 3 has a conductive filling portion 20b formed so as to block the through hole 13 at a position including the narrowed portion 14. As described above, in the manufacturing process of the through electrode substrate, the through electrode is formed thick by electrolytic plating. However, if the hole diameter p of the through hole 13 at the narrowed portion 14 is larger than 50 μm, the hole diameter at the narrowed portion 14 becomes too large, and in relation to the thickness t of the second surface side thin portion 20c described later, it becomes difficult to form the through electrode so as to block the through hole 13 at a position including the narrowed portion 14.

[0043] On the other hand, when the hole diameter p of the through-hole 13 in the narrowed portion 14 is 10 μm or more and 50 μm or less, the above-mentioned problems do not occur and the through-hole electrode substrate 1 can be obtained satisfactorily.

[0044] The opening diameter of the through hole 13 on the first surface 11 side of the substrate 10 is larger than the opening diameter p of the narrowed portion 14, and the opening diameter of the through hole 13 on the second surface 12 side of the substrate 10 is also larger than the opening diameter p of the narrowed portion 14.

[0045] Furthermore, in the through hole 13 shown in Figure 2, when viewed in cross section, it is preferable that the angle θ formed by a line connecting the edge (R1) of the narrowed portion 14 on one of the pair of side surfaces constituting the through hole 13 and the edge (R2) of the opening of the through hole 13 on the second surface 12 side of the substrate 10, and the normal N to the second surface 12 of the substrate 10 is 1.25° or more and 6.25° or less.

[0046] As described above, the manufacturing process for a through-hole electrode substrate includes a step of forming a seed layer to form a thick through-hole electrode by electroplating. However, if the angle θ is less than 1.25°, the slope of the side surface of the through-hole is close to vertical, and if the seed layer is formed by sputtering, it may not be possible to form a seed layer of the required thickness deep inside the through-hole, and the through-hole formed by subsequent electroplating may not be of the desired thickness.

[0047] Furthermore, as will be described later, the through electrode 20 of the through electrode substrate 1 shown in Figures 1 and 3 has a conductive filling portion 20b formed so as to block the through hole 13 at a position including the narrowed portion 14. As described above, in the manufacturing process of the through electrode substrate, the through electrode is formed thick by electrolytic plating. However, if the angle θ is smaller than 1.25°, the difference in hole diameter between the narrowed portion 14 of the through hole 13 and the second surface side portion 16 (more specifically, the portion formed by the side between the edge (R1) of the narrowed portion 14 shown in Figure 2 and the edge (R2) of the opening of the through hole 13 on the second surface 12 side of the substrate 10) also becomes small, making it difficult to form the conductive filling portion 20b to the desired length f in the through electrode 20 shown in Figures 1 and 3.

[0048] Furthermore, if the angle θ is greater than 6.25°, the opening of the through-hole 13 on the second surface 12 side becomes large, which may make it unsuitable for high-density mounting.

[0049] On the other hand, when the angle θ is equal to or greater than 1.25° and equal to or less than 6.25°, the above problems do not occur and a good through hole electrode substrate 1 can be obtained.

[0050] (Through electrode) The through electrode 20 is a conductive member, and is located in the through hole 13 in the through electrode substrate 1 as shown in FIG. More specifically, as shown in FIG. 3, the through electrode 20 has a conductive filling portion 20b formed to block the through hole 13 at a position including the narrowed portion 14 of the through hole 13, a first surface side thin-walled portion 20a formed on the side of the through hole 13 and extending from the conductive filling portion 20b toward the first surface 11 of the substrate 10, a second surface side thin-walled portion 20c formed on the side of the through hole 13 and extending from the conductive filling portion 20b toward the second surface 12 of the substrate 10, and a second surface side connection portion 20d formed on the second surface 12 of the substrate 10. As shown in Figures 1 and 3, the conductive filling portion 20b is formed to block the through hole 13, while the first surface side thin portion 20a and the second surface side thin portion 20c are formed to cover the side of the through hole 13 in a manner that leaves a space toward the center of the through hole 13.

[0051] In the case of a non-filled type (conformal via) in which the through electrode is provided on the side of the through hole and the center of the through hole is hollow, as the diameter of the through hole decreases, the thickness of the through electrode formed on the side of the through hole also decreases accordingly. The thickness of the through electrode needs to be reduced, especially in the narrowed portion of the through hole. This increases the electrical resistance of the through electrode, resulting in a problem of degraded electrical characteristics. Furthermore, if the thickness is too small, it becomes difficult to form the through electrode with a uniform thickness. On the other hand, since the through electrode 20 of the through electrode substrate 1 has the above-described configuration, even if the diameter of the through hole 13 is reduced, the presence of the conductive filling portion 20b at a position including the narrowed portion 14 of the through hole 13 eliminates the need to excessively reduce the thickness of the through electrode formed on the side surface of the through hole (for example, the thickness of the second-surface-side thin portion 20c), thereby eliminating the problem of reduced electrical characteristics. Furthermore, since there is no need to reduce the thickness excessively, it is also easy to form a uniform thickness.

[0052] Furthermore, in the case of filled vias, where the through electrode fills the entire through hole, there is a problem that cracks are likely to occur in the substrate due to the difference in thermal expansion coefficient between the through electrode material (typically copper (Cu)) that fills the entire inside of the through hole and the substrate due to the thermal stress of the heat cycle test. There is also a problem that gaps are likely to occur between the through electrode and the side of the through hole. On the other hand, the through electrode 20 of the through electrode substrate 1 has the conductive filling portion 20b only in part of the through hole, rather than in the entire through hole, so that the occurrence of cracks and gaps as described above can be effectively prevented.

[0053] The size of the conductive filling portion 20b shown in Figure 3 in the thickness direction of the substrate 10 (Z direction in the figure), more specifically, as shown in Figure 1, the length f of the conductive filling portion 20b from the first surface 11 side to the second surface 12 side of the substrate 10 at the center position (opening center position) of the through hole 13 in a planar view, is preferably 30 μm or more and 100 μm or less.

[0054] If the length f is less than 30 μm, it may be difficult to plate the holes. More specifically, when plating, the plating is performed thickly so as to block (in other words, to cover) the first surface 11 side of the through-holes 13, but if the length f is less than 30 μm, there may be portions that are not blocked (in other words, portions that cannot be covered) due to the unevenness of the plating thickness.

[0055] Furthermore, if the length f is greater than 100 μm, the thermal stress of the heat cycle test will likely cause cracks to form in the through hole substrate from the side surface of the through hole where the conductive filling portion 20b is located.

[0056] On the other hand, when the length f is 30 μm or more and 100 μm or less, the above problems do not occur and a good through hole electrode substrate 1 can be obtained.

[0057] 1 to avoid complication, the through electrode 20 is usually composed of multiple layers. For example, in the example shown in FIG. 3, the through electrode 20 has an adhesion layer 21 on the side surface of the through hole 13, a seed layer 22 on the adhesion layer 21, and a conductive layer 23 on the seed layer 22. In other words, the through electrode 20 has, in order from the side surface of the through hole 13 toward the center of the through hole 13, the adhesion layer 21, the seed layer 22, and the conductive layer 23.

[0058] The adhesion layer 21 is provided between the substrate 10 and the seed layer 22, and has the effect of increasing the adhesion between the substrate 10 and the seed layer 22. The adhesion layer 21 contains one of titanium (Ti), titanium nitride (TiN), and zinc oxide (ZnO), and is formed by sputter ion deposition, PVD, or a sol-gel method. The thickness of the adhesion layer 21 is, for example, 20 nm or more and 200 nm or less.

[0059] The seed layer 22 is a conductive layer that serves as a base for growing the conductive layer 23 by depositing metal ions in a plating solution during an electrolytic plating process to form the conductive layer 23. The seed layer 22 can be made of a conductive material such as copper (Cu), titanium (Ti), or a combination thereof. The material of the seed layer 22 may be the same as or different from the material of the conductive layer 23. The thickness of the seed layer 22 is, for example, 50 nm or more and 1000 nm or less. The seed layer 22 can be formed by, for example, sputtering, vapor deposition, or a combination of sputtering and vapor deposition.

[0060] The conductive layer 23 is a conductive layer formed by electrolytic plating on the seed layer 22. Examples of materials that can be used to form the conductive layer 23 include metals such as copper (Cu), gold (Au), silver (Ag), platinum (Pt), rhodium (Rh), tin (Sn), aluminum (Al), nickel (Ni), and chromium (Cr), alloys using these metals, and laminates of these metals.

[0061] The thickness t of the thin portion 20c on the second surface side of the through electrode substrate 1, more specifically, as shown in Figures 1 and 3, the thickness t of the thin portion 20c on the second surface side of the through electrode 20 at the height position of the second surface 12 of the substrate 10, is preferably 5 μm or more and 15 μm or less. 3, the thickness t of the second-surface-side thin portion 20c is the combined thickness of the adhesion layer 21, the seed layer 22, and the conductive layer 23. However, since the thicknesses of the adhesion layer 21 and the seed layer 22 are usually smaller than the thickness of the conductive layer 23, the thickness t may be considered to be approximate to the thickness of the conductive layer 23.

[0062] The through electrode 20 is electrically connected to the terminal of the element, but if the thickness t is less than 5 μm, the electrical resistance increases, resulting in a problem of degraded electrical characteristics.

[0063] Furthermore, if the thickness t is greater than 15 μm, the length f of the substrate 10 of the conductive filling portion 20b also increases as the thickness t increases, and as a result, the length f exceeds 100 μm, and as described above, due to the thermal stress of the heat cycle test, cracks are likely to occur in the through-hole substrate from the side of the through-hole where the conductive filling portion 20b is located.

[0064] On the other hand, when the thickness t is 5 μm or more and 15 μm or less, the above problems do not occur and a good through hole electrode substrate 1 can be obtained.

[0065] (Other embodiments) Hereinafter, another embodiment of the present disclosure will be described with reference to FIGS. First, the through electrode substrate 2 will be described with reference to Fig. 4. Here, Fig. 4 is a cross-sectional view showing a main part of the through electrode substrate 2. Note that components similar to those of the above-described through electrode substrate 1 are given the same reference numerals and will be described below.

[0066] In the through electrode substrate 1 illustrated in FIG. 1, nothing in particular is formed on the upper side (the center side of the through hole 13) of the second surface side thin portion 20c of the through electrode 20 illustrated in FIG. 3, leaving a space, but the through electrode substrate of the present disclosure is not limited to this and may be, for example, a form having an embedded resin portion 30, like the through electrode substrate 2 illustrated in FIG. 4.

[0067] More specifically, the through electrode substrate 2 illustrated in Figure 4 has the same configuration as the through electrode substrate 1 illustrated in Figure 1, and in addition thereto, an embedded resin portion 30 is formed on the thin portion 20c on the second surface side of the through electrode 20 shown in Figure 3, from the side of the conductive filling portion 20b of the through electrode 20 facing the second surface 12 of the substrate 10 toward the second surface 12 of the substrate 10.

[0068] The through electrode substrate 2 shown in Figure 4 has an embedded resin portion 30, which has the effect of alleviating stress and preventing foreign matter from remaining in the space above the thin-walled portion 20c on the second surface side of the through electrode 20 (towards the center of the through hole 13) when forming wiring on the second surface 12 side using a technique such as resist printing.

[0069] Here, it is preferable that the length fJ from the surface of the embedded resin portion 30 on the side of the second surface 12 of the substrate 10 to the second surface 12 of the substrate 10 is 0 μm or more and 50 μm or less in the normal direction of the second surface 12 of the substrate 10. If the length fJ is more than 50 μm, subsequent processes will be difficult.

[0070] One method for forming the embedded resin portion 30 is to attach a film made of the material that forms the embedded resin portion 30 to the second surface 12 of the substrate 10 of the through-hole electrode substrate 1 shown in Fig. 1, and then embed the embedded resin portion 30 in the through-hole by a method such as vacuum lamination. Any excess film remaining on the second surface 12 of the substrate 10 can be removed by scraping it off with a squeegee, for example. Alternatively, it can be removed by descumming using oxygen gas.

[0071] (Embedded resin part) The embedded resin portion 30 contains an organic material and has insulating properties. The embedded resin portion 30 may contain a photosensitive material. Examples of organic materials that can be used for the embedded resin portion 30 include polyimide, epoxy, benzocyclobutene resin, polyamide, phenolic resin, silicone resin, fluororesin, liquid crystal polymer, polyamideimide, polybenzoxazole, cyanate resin, aramid, polyolefin, polyester, BT resin, FR-4, FR-5, polyacetal, polybutylene terephthalate, syndiotactic polystyrene, polyphenylene sulfide, polyether ether ketone, polyether nitrile, polycarbonate, polyphenylene ether polysulfone, polyethersulfone, polyarylate, polyetherimide, etc. The above resins may be used alone or in combination of two or more types.

[0072] The embedded resin portion 30 may contain a filler (called an embedded resin filler) such as glass, talc, mica, silica, or alumina. To prevent cracks from occurring in the embedded resin portion 30 even after a heat cycle test, the embedded resin filler preferably has a thermogravimetric change of 3% by weight or less at 250°C and a thermal expansion coefficient of 1 ppm / K or more and 5 ppm / K or less. The embedded resin filler is preferably contained in an amount of 30% by volume or more and 80% by volume or less of the embedded resin portion 30.

[0073] 4, the dielectric loss tangent of the embedded resin part 30 at a frequency of 20 GHz is preferably 0.003 or more and 0.02 or less. This is because by setting the dielectric loss tangent at high frequencies of the embedded resin part 30 provided in the through hole 13 to a small value within a predetermined range, the transmission loss at high frequencies of the through electrode substrate 2 can be reduced. The embedded resin portion 30 is also required to have sufficient filling ability (e.g., no voids) in the through-holes, and components such as fillers are added to control the viscoelasticity. As a result, the dielectric loss tangent of the embedded resin portion 30 at a frequency of 20 GHz is 0.003 or more.

[0074] Next, the through electrode substrate 3 will be described with reference to Fig. 5. Here, Fig. 5 is a cross-sectional view showing a main part of the through electrode substrate 3. Note that components similar to those of the above-described through electrode substrate 1 and through electrode substrate 2 are denoted by the same reference numerals and will be described below.

[0075] The through hole electrode substrate 3 shown in Fig. 5 has an insulating resin layer 40 in addition to the configuration of the through hole electrode substrate 2 shown in Fig. 4. More specifically, the through hole electrode substrate 3 shown in Fig. 5 has an insulating resin layer 40 on the side of second surface 12 of substrate 10 and from the side of second surface 12 of substrate 10 of embedded resin portion 30 in through hole 13 toward the side of second surface 12 of substrate 10.

[0076] The through electrode substrate 3 shown in Figure 5 has an insulating resin layer 40 in addition to the embedded resin portion 30, which can further reduce stress and prevent foreign matter from remaining in the space above the thin-walled portion 20c on the second surface side of the through electrode 20 (towards the center of the through hole 13) when forming wiring on the second surface 12 side using a technique such as resist printing.

[0077] One method for forming the insulating resin layer 40 is to attach a film made of the material that forms the insulating resin layer 40 to the second surface 12 of the substrate 10 of the through-hole electrode substrate 2 shown in Figure 4, and then embed the insulating resin layer 40 in the through-holes by a method such as vacuum lamination. Any excess film remaining on the second surface 12 of the substrate 10 can be removed by scraping it off with a squeegee, for example. It can also be removed by descumming using oxygen gas.

[0078] (insulating resin layer) The insulating resin layer 40 contains an organic material and has insulating properties. The insulating resin layer 40 may contain a photosensitive material. Examples of organic materials that can be used for the insulating resin layer 40 include polyimide, epoxy, benzocyclobutene resin, polyamide, phenolic resin, silicone resin, fluororesin, liquid crystal polymer, polyamideimide, polybenzoxazole, cyanate resin, aramid, polyolefin, polyester, BT resin, FR-4, FR-5, polyacetal, polybutylene terephthalate, syndiotactic polystyrene, polyphenylene sulfide, polyether ether ketone, polyether nitrile, polycarbonate, polyphenylene ether polysulfone, polyethersulfone, polyarylate, polyetherimide, etc. The above resins may be used alone or in combination of two or more types.

[0079] The insulating resin layer 40 may contain a filler (referred to as an insulating resin filler) such as glass, talc, mica, silica, or alumina. To prevent cracks from occurring in the insulating resin layer 40 even after a heat cycle test, the insulating resin filler preferably has a thermogravimetric change of 3% by weight or less at 250°C and a thermal expansion coefficient of 1 ppm / K or more and 5 ppm / K or less. The insulating resin filler is preferably contained in the insulating resin layer 40 in an amount of more than 0% by volume and 40% by volume or less.

[0080] 5, the dielectric loss tangent of the insulating resin layer 40 at a frequency of 20 GHz is preferably 0.001 or more and 0.01 or less. This is because by setting the dielectric loss tangent of the insulating resin layer 40 at high frequencies to a small value within a predetermined range, the transmission loss of the through hole electrode substrate 3 at high frequencies can be reduced.

[0081] <Method of manufacturing a through electrode substrate> Next, an example of a method for manufacturing a through hole electrode substrate according to the present disclosure will be described with reference to FIGS.

[0082] (Manufacturing of substrates with through holes) First, a substrate including a first surface 11 and a second surface 12 located on the opposite side of the first surface 11 is prepared, and a laser is irradiated from each side of the first surface 11 and the second surface 12 to produce a substrate 10 having a through hole 13 of the desired shape, as shown in Figure 6. For example, by irradiating a laser from the side of the first surface 11, a portion of the through hole 13 from the first surface 11 of the substrate 10 to the narrowed portion 14 (corresponding to the first surface side portion 15) can be formed, and by irradiating a laser from the side of the second surface 12, a portion of the through hole 13 from the second surface 12 of the substrate 10 to the narrowed portion 14 (corresponding to the second surface side portion 16) can be formed.

[0083] Lasers that can be used for laser processing include excimer lasers, Nd:YAG lasers, femtosecond lasers, etc. When using an Nd:YAG laser, it is possible to use 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.

[0084] In addition, as another manufacturing method, first, a resist layer having an opening at a position corresponding to the through hole 13 is provided on the first surface 11 and the second surface 12 of the substrate, and then the through hole 13 is formed by etching from the opening in the resist layer.

[0085] The above processing may be performed in the same process from the first surface 11 side and the second surface 12 side of the substrate, or one side may be processed first and then the other side. For example, first, a resist layer having an opening at a position corresponding to through hole 13 is provided on first surface 11 of the substrate, and etching is performed from the opening in the resist layer to form the portion of through hole 13 on the first surface 11 side (corresponding to first surface side portion 15), and then a resist layer having an opening at a position corresponding to through hole 13 is provided on second surface 12 of the substrate, and etching is performed from the opening in the resist layer to form the portion of through hole 13 on the second surface 12 side (corresponding to second surface side portion 16).

[0086] As the etching method, dry etching methods such as reactive ion etching and deep reactive ion etching, wet etching, etc. can be used.

[0087] The above-described laser irradiation and wet etching can also be combined as appropriate. For example, first, an altered layer is formed in the region of the substrate where the through-hole 13 is to be formed by laser irradiation, and then the substrate is immersed in hydrogen fluoride or the like to etch the altered layer. The through-hole 13 may be formed by such a method.

[0088] Alternatively, the through holes 13 may be formed by blasting the substrate with an abrasive material.

[0089] (Formation of through electrodes) Next, the through electrodes 20 are formed. To form the through electrode 20, first, an adhesion layer 21 is formed on the first surface 11, the second surface 12, and the side surface of the through hole 13 of the substrate 10 by sputter ion deposition, PVD, or a sol-gel method, or a combination thereof, and then a seed layer 22 is formed on the adhesion layer 21 by a sputtering method, a vapor deposition method, or a combination thereof. For ease of understanding, in Figures 7 to 14, the adhesion layer 21 and seed layer 22 are shown as an underlayer 24 (a black thick film). However, since the adhesion layer 21 and seed layer 22 are usually thinner than the conductive layer 23, the underlayer 24 is not shown in Figures 1 and 3 to 5 described above. Next, as shown in FIG. 8, a resist layer 51 is formed on the base layer 24 formed on the first surface 11 of the substrate 10, and a resist layer 52 is partially formed on the base layer 24 formed on the second surface 12. Subsequently, as shown in FIG. 9, the conductive layer 23 is formed by electrolytic plating on the underlayer 24 that is not covered with the resist layers 51 and 52. Next, as shown in FIG. 10, the resist layers 51 and 52 are removed, and further, as shown in FIG. 11, the portions of the underlayer 24 that were covered with the resist layers 51 and 52 are removed by, for example, wet etching. Thereafter, as shown in FIG. 12, the first surface 11 side is polished by a method such as CMP (Chemical Mechanical Polishing) to form the through electrodes 20 in a desired shape. In this way, the through hole electrode substrate 1 shown in Fig. 1 can be obtained. Note that in the through hole electrode substrate 1 shown in Fig. 1, the illustration of the base layer 24 is omitted to avoid complication.

[0090] Here, to explain in detail the process of forming the conductive layer 23 by the above-mentioned electrolytic plating method (Figure 9), in this embodiment, the substrate 10 on which the resist layers 51 and 52 have been formed is immersed in a plating solution, anode electrodes are placed on the first surface 11 side and the second surface 12 side of the substrate 10, and power is supplied to the base layer 24 to grow the conductive layer 23 on the base layer 24 that is not covered by the resist layers 51 and 52. At this time, the conductive layer 23 first grows on the base layer 24 that is not covered by the resist layers 51 and 52, increasing in thickness, and eventually, at the narrowed portion 14, the conductive layers 23 that have grown on the base layer 24 come into contact with each other to form a conductive filling portion 20b that blocks the through hole. Thereafter, when the through electrode 20 has a desired shape, the power supply to the underlayer 24 can be stopped.

[0091] (Formation of embedded resin part) To manufacture the through electrode substrate 2 illustrated in Figure 4, as shown in Figure 13, it is sufficient to form an embedded resin portion 30 on the second surface side thin portion 20c of the through electrode 20 of the through electrode substrate 1 manufactured as described above.

[0092] For example, first, a film made of a material that will become the embedded resin portion 30, including a photosensitive material, is attached to the opening of the through-hole 13 on the second surface 12 of the substrate 10 by a method such as vacuum lamination. Next, the film is subjected to an exposure process and a development process. This allows the embedded resin portion 30 made of the film to be formed. In this way, the through hole electrode substrate 2 shown in Fig. 4 can be obtained. Note that in the through hole electrode substrate 2 shown in Fig. 4, the illustration of the base layer 24 is omitted to avoid complication.

[0093] (Formation of insulating resin layer) To manufacture the through-hole electrode substrate 3 illustrated in Figure 5, as shown in Figure 14, an insulating resin layer 40 may be formed on the second surface 12 of the substrate 10 of the through-hole electrode substrate 2 manufactured as described above, and from the second surface 12 of the substrate 10 of the embedded resin portion 30 in the through hole 13 toward the second surface 12 of the substrate 10.

[0094] For example, first, a film made of a material that will become the insulating resin layer 40 and that contains a photosensitive material is attached to the opening of the through-hole 13 on the second surface 12 of the substrate 10 by a method such as vacuum lamination. Next, the film is subjected to an exposure process and a development process. This allows the insulating resin layer 40 made of the film to be formed. In this way, the through hole electrode substrate 3 shown in Fig. 5 can be obtained. Note that in the through hole electrode substrate 3 shown in Fig. 5, the illustration of the base layer 24 is omitted to avoid complication. [Example]

[0095] Hereinafter, embodiments of the present disclosure will be described in detail with reference to examples and comparative examples, but the embodiments of the present disclosure are not limited to the examples.

[0096] (Examples 1 to 13) Through holes of various dimensions shown in Table 1 were formed in a 200 mm diameter non-alkali glass substrate (EN-Al manufactured by Asahi Glass Co., Ltd.) by laser processing and wet etching using hydrogen fluoride. In addition, an adhesion layer having a thickness of 50 nm and made of zinc oxide (ZnO) was formed by a sol-gel method at predetermined locations, such as the side surfaces of the through holes, and then a seed layer having a thickness of 0.5 μm and made of copper (Cu) was formed by an electroless plating method. Thereafter, a conductive layer made of copper (Cu) was formed by electrolytic plating to form through electrodes having the dimensions shown in Table 1. In this manner, through electrode substrates of Examples 1 to 13 having the dimensions shown in Table 1 were prepared.

[0097] (Measurements of each dimension) An ion milling machine (Hitachi High-Tech, IM-4000) was used to obtain a cross section of each through-hole substrate, as shown in Figure 1. The diameter of the through-hole was measured using a length-measuring optical microscope (Olympus, STM-6-LM) and compared to the diameter of the through-hole in a plan view before the cross section was obtained, confirming that the cross section passed within ±5% of the center of the through-hole opening. The hole diameter p, length f, thickness t, distance d, and thickness g shown in FIG. 1 were obtained by measuring the cross section with a length measuring optical microscope (Olympus Corporation, STM-6-LM).

[0098] Here, the hole diameter p shown in Table 1 is a value measured as the distance between the two closest points on the left and right side surfaces of through hole 13 in the cross section. Also, the length f shown in Table 1 is a value measured as the distance between two points where a line passing through the center of the opening in the cross section of through hole 13 intersects with the upper surface (the surface on the first surface 11 side) and the lower surface (the surface on the second surface 12 side) of conductive filling portion 20b. Also, the distance d shown in Table 1 is the average value of the values ​​obtained on the left and right side surfaces of the cross section of through hole 13.

[0099] In addition, the angle θ shown in Table 1 was determined by drawing a line (the line connecting R1 and R2 shown in Figure 2) from the cross-sectional photograph connecting the edge of the narrowed portion 14 on the right side of the cross-section of the through hole 13 (the part where the left and right sides of the through hole 13 are closest in the cross-section) to the edge of the opening of the through hole 13 on the second surface 12 side of the substrate 10, and defining the angle between this line and the normal N to the second surface 12 of the substrate 10.

[0100] (Comparative Examples 1 to 4) In the same manner as in Example 1, through hole electrode substrates of Comparative Examples 1 to 4 having various dimensions shown in Table 2 were prepared. Here, in Comparative Example 1, the value of pore diameter p is smaller than the values ​​in Examples 1 to 13, in Comparative Example 2, the value of pore diameter p is larger than the values ​​in Examples 1 to 13, in Comparative Example 3, the value of length f is smaller than the values ​​in Examples 1 to 13, and in Comparative Example 4, the value of length f is larger than the values ​​in Examples 1 to 13.

[0101] (evaluation) Each of the through hole electrode substrates of Examples 1 to 13 and Comparative Examples 1 to 4 was heated in a vacuum from -55°C to 125°C over one hour, held at 125°C for one hour, and then cooled from 125°C to -55°C over one hour. This process was repeated 1000 times, after which the front and back surfaces of each through hole electrode substrate were observed using an optical microscope (Olympus STM-6-LM) to evaluate the occurrence of cracks and gaps. The results are shown in Tables 1 and 2.

[0102] [Table 1]

[0103] [Table 2]

[0104] As shown in Table 1, no cracks or gaps were found in any of Examples 1 to 13, and the results were good. On the other hand, as shown in Table 2, cracks or gaps were found in all of Comparative Examples 1 to 4, and it was found that they were defective.

[0105] (Examples 14 to 33) Various embedded resin portions and insulating resin layers shown in Table 3 were formed in the through hole electrode substrates of Examples 1 to 13 above, to prepare through hole electrode substrates of Examples 14 to 33 having the configuration shown in Fig. 5. Here, the thickness of the insulating resin portion (more specifically, the thickness from second surface 12 of substrate 10 to the outermost surface of insulating resin layer 40 in Fig. 5) was set to 25 µm.

[0106] (evaluation) The through hole electrode substrates of Examples 14 to 33 were heated in a vacuum from -55°C to 125°C over 1 hour, held at 125°C for 1 hour, and then cooled from 125°C to -55°C over 1 hour. This process was repeated 1000 times, after which the front and back surfaces of each through hole electrode substrate were observed using an optical microscope (Olympus STM-6-LM) to evaluate the occurrence of cracks and gaps. The results are shown in Table 3.

[0107] Here, in Table 3, "fJ" refers to the length fJ (unit: μm) from the surface of the embedded resin part 30 on the side of the second surface 12 of the substrate 10 to the second surface 12 of the substrate 10 in the normal direction of the second surface 12 of the substrate 10, as shown in Figure 4. "Tan δ" refers to the dielectric loss tangent of the embedded resin portion and the insulating resin layer at a frequency of 20 GHz. In addition, "weight change" refers to the weight change (unit: weight %) of the embedded resin filler contained in the embedded resin part at 250°C in the embedded resin part, and refers to the weight change (unit: weight %) of the insulating resin filler contained in the insulating resin layer at 250°C in the insulating resin layer. In addition, "CTE" refers to the thermal expansion coefficient (unit: ppm / K) of the embedded resin filler contained in the embedded resin part, and in the insulating resin layer, refers to the thermal expansion coefficient (unit: ppm / K) of the insulating resin filler contained in the insulating resin layer. In addition, "volume ratio" refers to the volume ratio (unit: %) of the embedded resin filler contained in the embedded resin portion at 25°C, and in the insulating resin layer, refers to the volume ratio (unit: %) of the insulating resin filler contained in the insulating resin layer at 25°C.

[0108] [Table 3]

[0109] As shown in Table 3, no cracks or gaps were found in any of Examples 14 to 33, and the results were good. [Explanation of symbols]

[0110] 1, 2, 3 Through-hole electrode substrate 10 Substrate 11 Page 1 12 Side 2 13 Through hole 14 Stenosis 15 First side part 16 Second side part 20 Through electrode 20a Thin-walled part on the first surface 20b Conductive filling part 20c Thin wall part on second side 20d Second surface connection part 21 Adhesion layer 22 Seed Layer 23 Conductive layer 24 Base layer 30 Buried resin part 40 insulating resin layer 51, 52 Resist layer

Claims

1. a substrate including a first surface and a second surface located opposite to the first surface and having a through hole; a through electrode located in the through hole of the substrate, the through hole has a narrowed portion where the hole diameter is minimum, The through electrode is an adhesion layer, a seed layer, and a conductive layer are provided in this order from a side surface of the through hole toward a center of the through hole, the adhesion layer contains one of titanium, titanium nitride, and zinc oxide; the conductive layer comprises copper; Furthermore, the through electrode is a conductive filling portion formed at a position including the narrowed portion so as to close the through hole; a first surface-side thin portion formed on a side surface of the through hole and extending from the conductive filling portion toward the first surface of the substrate; a second surface-side thin portion formed on a side surface of the through hole and extending from the conductive filling portion toward the second surface of the substrate; a second surface side connection portion formed on the second surface of the substrate; It has The diameter p of the through hole in the narrowed portion is 10 μm or more and 50 μm or less, a length f of the conductive filling portion at a center position of the through hole in a plan view from the first surface side to the second surface side of the substrate is 30 μm or more and 100 μm or less; an angle θ formed by a line connecting an edge of the narrowed portion and an edge of the opening of the through hole on the second surface side of the substrate, on one side of a pair of side surfaces constituting the through hole in a cross-sectional view, and a normal to the second surface of the substrate, is 1.25° or more and 6.25° or less; a buried resin portion is formed in the through hole from the side of the conductive filling portion of the through electrode toward the second surface of the substrate, The embedded resin portion has a dielectric loss tangent of 0.003 or more and 0.02 or less at a frequency of 20 GHz, The embedded resin portion contains an embedded resin filler, The embedded resin filler is The thermogravimetric change is within 3% by weight at 250°C, A thermal expansion coefficient is 1 ppm / K or more and 5 ppm / K or less, The embedded resin filler is contained in the embedded resin portion in an amount of 30% by volume or more and 80% by volume or less, an insulating resin layer is provided on the second surface side of the substrate and on the embedded resin portion in the through hole from the second surface side of the substrate toward the second surface side of the substrate; the insulating resin layer has a dielectric loss tangent of 0.001 or more and 0.01 or less at a frequency of 20 GHz; the insulating resin layer contains an insulating resin filler, The insulating resin filler is The thermogravimetric change is within 3% by weight at 250°C, A thermal expansion coefficient is 1 ppm / K or more and 5 ppm / K or less, The through electrode substrate, wherein the insulating resin filler is contained in the insulating resin layer in an amount of more than 0% by volume and not more than 40% by volume.

2. The through electrode substrate according to claim 1 , wherein a thickness t of the second surface side thin portion of the through electrode at a height position of the second surface of the substrate is 5 μm or more and 15 μm or less.

3. the narrowed portion of the through hole is located at a distance d from the first surface toward the second surface of the substrate, 3. The through hole electrode substrate according to claim 1, wherein the distance d is 20 μm or more and is ½ or less of the thickness g of the substrate.

4. The through hole electrode substrate according to claim 1 , wherein the thickness g of the substrate is 200 μm or more and 500 μm or less.

5. 5. The through electrode substrate according to claim 1, wherein a length fJ from a surface of the embedded resin portion on the side of the second surface of the substrate to the second surface of the substrate in a normal direction of the second surface of the substrate is 0 μm or more and 50 μm or less.

Images