Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
  • H05K3/42—Plated through-holes or plated via connections
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/11—Printed elements for providing electric connections to or between printed circuits
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K1/00—Printed circuits
  • H05K1/02—Details
  • H05K1/11—Printed elements for providing electric connections to or between printed circuits
  • H05K1/115—Via connections; Lands around holes or via connections
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
  • H05K3/42—Plated through-holes or plated via connections
  • H05K3/423—Plated through-holes or plated via connections characterised by electroplating method
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
  • H05K3/42—Plated through-holes or plated via connections
  • H05K3/425—Plated through-holes or plated via connections characterised by the sequence of steps for plating the through-holes or via connections in relation to the conductive pattern
  • H05K3/427—Plated through-holes or plated via connections characterised by the sequence of steps for plating the through-holes or via connections in relation to the conductive pattern initial plating of through-holes in metal-clad substrates
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K3/00—Apparatus or processes for manufacturing printed circuits
  • H05K3/40—Forming printed elements for providing electric connections to or between printed circuits
  • H05K3/42—Plated through-holes or plated via connections
  • H05K3/429—Plated through-holes specially for multilayer circuits, e.g. having connections to inner circuit layers

Definitions

• Embodiments of the present disclosure relate to a through-electrode substrate and a method for manufacturing the through-electrode substrate.
• a through electrode substrate is a component that includes a substrate having a first surface and a second surface, a through hole formed in the substrate, and a through electrode located in the through hole.
• the through electrode substrate is used, for example, as an interposer.
• An interposer is a component that is interposed between two electrical components.
• a through electrode substrate is interposed between two LSI chips in the thickness direction.
• a through electrode substrate may also be interposed between an element such as an LSI chip and a mounting substrate such as a motherboard.
• a through electrode substrate is also used as a component that constitutes passive components such as inductors and capacitors.
• 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.
• a resin material is filled into the space of the through hole where no conductive material is present.
• the allowable current there is a demand to increase the maximum value of the current that can be passed through the through electrode (hereinafter also referred to as the allowable current).
• the allowable current 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.
• the larger the dimension of the through hole the more likely defects such as voids will occur in the conductive material filled in the through hole.
• the through electrodes of the second and third examples as well the larger the dimension of the through hole in the surface direction, the higher the allowable current of the through electrode. The larger the dimension of the through hole, the more likely defects such as voids will occur in the resin material filled in the through hole.
• Embodiments of the present disclosure relate to the following [1] to [20].
• 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 partially in the through hole; a resin layer partially 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 narrowest portion, the minimum dimension being a minimum value of the dimension of the through hole in a planar direction of the first surface
• the through electrode includes a closing portion that closes the through hole at least at the narrowest portion, a third portion located on the wall surface between the first surface and the closing portion, and a fourth portion located on the wall surface between the second surface and the closing portion
• the resin layer includes a first resin layer located inside the third portion and a second resin layer located inside the
• the through electrode may include a first portion located on the first surface and connected to the third portion.
• the through-electrode substrate may include a first surface resin layer located on the first surface, and the first surface resin layer may overlap the boundary between the wall surface and the third portion in a plan view.
• the through-electrode substrate may include a second surface resin layer located on the second surface, and the second surface resin layer may overlap the boundary between the wall surface and the fourth portion in a plan view.
• the ratio of the thickness of the closed portion to the thickness of the substrate may be 0.20 or more and 0.40 or less.
• the through hole has a first dimension at the first end and a second dimension at the second end in the planar direction of the first surface, and the ratio of the first dimension to the minimum dimension may be 2.0 or more, and the ratio of the second dimension to the minimum dimension may be 2.0 or more.
• the ratio of the first dimension to the minimum dimension may be 3.0 or less, and the ratio of the second dimension to the minimum dimension may be 3.0 or less.
• the ratio of the second dimension to the first dimension may be 0.80 or more and 1.20 or less.
• the minimum dimension may be 60 ⁇ m or more.
• the ratio of the minimum dimension to the thickness of the third portion may be 3.0 or less, and the ratio of the minimum dimension to the thickness of the fourth portion may be 3.0 or less.
• the thickness of the third portion and the thickness of the fourth portion may be 20 ⁇ m or more.
• the variation in thickness of the third portion may be 0.10 ⁇ m or less.
• the through electrode may include a seed layer and a plating layer located on the seed layer.
• the plating layer may contain copper.
• a mounting board [1] to [17], and an element electrically connected to the through electrode of the through electrode substrate.
• a method for producing a through hole electrode substrate comprising: preparing 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-hole forming step of partially forming a through-hole in the through-hole; and forming a resin layer partially 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 narrowest portion, the minimum dimension being a minimum value of the dimension of the through hole in a planar 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 first plating step of forming a closing portion that closes the through hole at least in the narrowest portion, and a
• FIG. 1 is a cross-sectional view showing a through electrode substrate according to an embodiment.
• FIG. 2 is a cross-sectional view showing an example of a through hole in a substrate.
• FIG. 2 is a cross-sectional view showing an example of a through electrode.
• FIG. 4 is a cross-sectional view showing an example of dimensions of a through electrode.
• 1A to 1C are cross-sectional views showing an example of a step of preparing a substrate.
• 10A to 10C are cross-sectional views showing an example of a seed layer forming step.
• FIG. 4 is a cross-sectional view showing an example of a plating layer forming step.
• FIG. 4 is a cross-sectional view showing an example of a plating layer forming step.
• FIG. 4 is a cross-sectional view showing an example of a plating layer forming step.
• 10A to 10C are cross-sectional views showing an example of a step of removing a part of the seed layer.
• FIG. 4 is a cross-sectional view showing an example of a resin layer forming step.
• FIG. 4 is a cross-sectional view showing a through electrode substrate according to a first comparative embodiment.
• FIG. 11 is a cross-sectional view showing a through electrode substrate according to a second comparative embodiment.
• FIG. 11 is a cross-sectional view showing a through electrode substrate according to a third comparative embodiment.
• FIG. 13 is a cross-sectional view showing a through electrode substrate according to a fourth comparative embodiment.
• FIG. 13 is a cross-sectional view showing a through electrode substrate according to a fifth comparative embodiment.
• FIG. 13 is a cross-sectional view showing a through electrode substrate according to a sixth comparative embodiment.
• FIG. 11 is a cross-sectional view showing a modified example of a through electrode substrate.
• 1A to 1C are diagrams showing examples of products on which a through electrode substrate is mounted.
• 1 is a table showing the evaluation results of Examples 1 to 12.
• 1 is a table showing the evaluation results of Comparative Examples 1 to 9.
• 1 is a table showing the evaluation results of Examples 13 to 17.
• 1 is a table showing the evaluation results of Comparative Examples 10 to 12.
• FIG. 11 is a cross-sectional view showing a modified example of the through electrode.
• FIG. 10A to 10C are cross-sectional views showing an example of a seed layer forming step.
• FIG. 4 is a cross-sectional view showing an example of a plating layer forming step.
• FIG. 4 is a cross-sectional view showing an example of a resin layer forming step.
• 4A to 4C are cross-sectional views showing an example of a polishing step.
• FIG. 11 is a cross-sectional view showing a modified example of the through electrode.
• 4A to 4C are cross-sectional views showing an example of a polishing step.
• FIG. 4 is a cross-sectional view showing an example of a resin layer forming step.
• FIG. 11 is a cross-sectional view showing a modified example of a through electrode substrate.
• FIG. 11 is a cross-sectional view showing a modified example of a through electrode substrate.
• FIG. 13 is a plan view showing a modified example of the through electrode substrate.
• FIG. 11 is a cross-sectional view showing a modified example of a through electrode substrate.
• 4A to 4C are cross-sectional views showing an example of a step of forming a first-side resin layer and a second-side resin layer.
• 5A to 5C are cross-sectional views showing an example of a step of forming a conductive layer.
• 5A to 5C are cross-sectional views showing an example of a step of forming a conductive layer.
• 5A to 5C are cross-sectional views showing an example of a step of forming a conductive layer.
• 5A to 5C are cross-sectional views showing an example of a step of forming a conductive layer.
• the configuration of the through-hole electrode substrate and the manufacturing method thereof will be described in detail with reference to the drawings.
• the following embodiment is an example of an embodiment of the present disclosure, and the present disclosure is interpreted as being limited to these embodiments, but there are no omissions.
• the terms "substrate”, “base material”, “sheet”, “film”, etc. are not distinguished from each other based only on the difference in name.
• “substrate” is a concept that includes members that can be called sheets and films.
• “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 in a global perspective.
• the normal direction used for a plate-like member refers to the normal direction to the surface of the member.
• Terms such as “parallel” and “orthogonal” and values of length and angle that specify the shape and geometric conditions and their degree used in this specification are interpreted to include the range of the degree to which similar functions can be expected without being bound by strict meaning.
• the numerical range of the parameter may be constructed by combining any one of the upper limit candidates and any one of the lower limit candidates.
• Parameter B is, for example, A1 or more, and may be A2 or more, or may be A3 or more.
• Parameter B is, for example, A4 or less, and may be A5 or less, or may be A6 or less.”
• 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.
• FIG. 1 is a cross-sectional view showing an example of a through electrode substrate 10.
• the through electrode substrate 10 includes a substrate 12, a through electrode 20, and a resin layer 30.
• the substrate 12 includes a first surface 13 and a second surface 14 located on the opposite side of the first surface 13.
• the substrate 12 further includes a plurality of through holes 15 penetrating from the first surface 13 to the second surface 14.
• the through electrode 20 and the resin layer 30 are located in the through holes 15.
• the through electrode substrate 10 may include a first conductive layer 35 located on the first surface 13.
• the through electrode substrate 10 may include a second conductive layer 36 located on the second surface 14.
• the substrate 12 includes an inorganic material having insulating properties.
• 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.
• Alkali-free glass is glass that does not contain alkaline components such as sodium or potassium.
• Alkali-free glass contains, for example, boric acid instead of an alkaline component.
• alkali-free glass contains, for example, an alkaline earth metal oxide such as calcium oxide or barium oxide.
• FIG. 2 is a cross-sectional view showing the substrate 12.
• 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 narrowest portion 163 located between the first end 161 and the second end 162.
• the first end 161 is the 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 the 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 the 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 the minimum value.
• the first end 161, the second end 162, and the smallest portion 163 may have a circular outline in a plan view.
• the first dimension R1, the second dimension R2, and the smallest portion 163 refer to the diameters of the first end 161, the second end 162, and the smallest portion 163.
• Plan view refers to viewing the object along the normal direction of the first surface 13.
• the minimum dimension R3 is smaller than the first dimension R1.
• the dimension of the through hole 15 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 through hole 15 may decrease monotonically from the second end 162 to the minimum portion 163.
• the minimum dimension R3 is, for example, 58 ⁇ m or more, and may be 60 ⁇ m or more. Since the minimum dimension R3 is 58 ⁇ m 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, 67 ⁇ m or less, and may be 65 ⁇ m or less. Since the minimum dimension R3 is 67 ⁇ m or less, it becomes easier for a closed portion 25, described later, to be formed in the minimum portion 163.
• the ratio R1/R3 of the first dimension R1 to the minimum dimension R3 is, for example, 2.0 or more, and may be 2.2 or more, or may be 2.5 or more. Since the ratio R1/R3 is 2.0 or more, the allowable current of the through electrode 20 formed in the through hole 15 is sufficiently increased.
• the ratio R1/R3 is, for example, 3.2 or less, and may be 3.0 or less, or may be 2.8 or less.
• the ratio R2/R3 of the second dimension R2 to the minimum dimension R3 is, for example, 2.0 or more, and may be 2.2 or more, or may be 2.5 or more. Since the ratio R2/R3 is 2.0 or more, the allowable current of the through electrode 20 formed in the through hole 15 is sufficiently increased.
• the ratio R2/R3 is, for example, 3.2 or less, and may be 3.0 or less, or may be 2.8 or less.
• the ratio R2/R3 may be the same as or different from the ratio R1/R3.
• 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, 0.8 or more, and may be 0.9 or more.
• the ratio R2/R1 is, for example, 1.2 or less, and may be 1.1 or less.
• the minimum portion 163 may be located halfway between the first surface 13 and the second surface 14 in the thickness direction of the substrate 12.
• the symbol K3 represents the distance from the first surface 13 to the minimum portion 163 in the thickness direction of the substrate 12.
• the ratio of the distance K3 to the thickness T0 of the substrate, K3/T0 is 0.50.
• the position of the minimum portion 163 in the thickness direction of the substrate 12 may deviate from the middle between the first surface 13 and the second surface 14. That is, the ratio K3/T0 may deviate from 0.50.
• the ratio K3/T0 may be, for example, 0.40 or more, and may be 0.45 or more.
• the ratio K3/T0 may be, for example, 0.60 or less, and may be 0.55 or less.
• (Through electrode) 3 is a cross-sectional view showing an example of the through electrode 20.
• the through electrode 20 is partially located in the through hole 15. "Partially" means that the entire space of the through hole 15 is not occupied by the through electrode 20.
• the through electrode 20 extends along the through hole 15 from the first surface 13 to the second surface 14.
• the through electrode 20 includes a conductive material.
• the through electrode 20 includes at least a plating layer 201.
• the plating layer 201 is a layer having conductivity and formed by a plating method such as electrolytic plating.
• the through electrode 20 may include a seed layer 202.
• the seed layer 202 is located between the plating layer 201 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 202 is a layer having conductivity and formed by physical film formation such as sputtering.
• the majority of the through electrode 20 is composed of the plating layer 201.
• the ratio of the thickness of the plating layer 201 to the thickness of the through electrode 20 located on the wall surface 16 is, for example, 0.80 or more, and may be 0.90 or more.
• the plating layer 201 may contain metals such as copper, gold, silver, platinum, rhodium, tin, aluminum, nickel, titanium, chromium, zinc, etc., or alloys using these metals.
• the seed layer 202 may contain metal materials such as copper, nickel, titanium, chromium, zinc, etc.
• the seed layer 202 may contain compounds of these metal materials.
• the resin layer 30 is partially located in the through hole 15.
• the resin layer 30 is made of a resin material filled in the space of the through hole 15 where the through electrode 20 is not present.
• the resin layer 30 includes a first resin layer 31 located inside the third portion 23 of the through electrode 20, and a second resin layer 32 located inside the fourth portion 24 of the through electrode 20.
• the "inside” refers to a direction approaching the center of the through hole 15 in a plan view.
• the resin layer 30 contains an insulating resin material.
• the resin material is an organic material such as polyimide, epoxy, acrylic, or polyphenyl ether.
• FIG. 4 is a cross-sectional view showing an example of the dimensions of the through electrode 20.
• the resin layer 30 is omitted.
• symbol K1 represents the maximum distance from the first surface 13 to the closed portion 25 in the thickness direction of the substrate 12.
• Distance K1 is also referred to as the first distance.
• Symbol K2 represents the maximum distance from the second surface 14 to the closed portion 25 in the thickness direction of the substrate 12.
• Distance K2 is also referred to as the second distance.
• the first distance K1 and the second distance K2 are relatively large.
• the ratio K1/T0 of the first distance K1 to the thickness T0 of the substrate 12 is, for example, 0.10 or more, may be 0.15 or more, or may be 0.20 or more.
• the ratio K1/T0 is, for example, 0.40 or less, may be 0.35 or less, or may be 0.30 or less.
• the ratio K2/T0 of the second distance K2 to the thickness T0 of the substrate 12 is, for example, 0.10 or more, may be 0.15 or more, or may be 0.20 or more.
• the ratio K2/T0 is, for example, 0.40 or less, 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.
• the ratio T5/T0 of the thickness T5 of the closed portion 25 to the thickness T0 of the substrate 12 is, for example, 0.20 or more, and may be 0.25 or more.
• the ratio T5/T0 is, for example, 0.40 or less, and may be 0.35 or less.
• a thermal cycle test of the through electrode substrate 10 is performed to evaluate the reliability of the through electrode substrate 10.
• the temperature of the through electrode substrate 10 is repeatedly increased or decreased.
• One thermal cycle includes a temperature increase process, a high-temperature holding process, a temperature decrease process, and a low-temperature holding process.
• the thermal cycle test includes, for example, 1,000 thermal cycles.
• the thickness T5 of the closing portion 25 that closes the through hole 15 is smaller than the thickness T0 of the substrate 12. That is, the through hole 15 is not closed by the through electrode 20 at the position of the first end 161. Moreover, the through hole 15 is not closed by the through electrode 20 at the position of the second end 162. According to this embodiment, the thermal stress at the first end 161 and the second end 162 is reduced compared to when the entire area of the through hole 15 is filled with the through electrode 20. Therefore, the occurrence of defects such as cracks in the substrate 12 is suppressed.
• the symbol ⁇ 1 represents the angle between the first surface 13 and the wall surface 16 at the first end 161.
• the angle ⁇ 1 may be greater than 90°. Because the through hole 15 includes a minimum portion 163, the angle ⁇ 1 can be greater than 90°.
• the angle ⁇ 1 is, for example, 95° or more, may be 100° or more, or may be 105° or more.
• the angle ⁇ 1 is, for example, 150° or less, may be 135° or less, or may be 120° or less.
• the symbol ⁇ 2 represents the angle between the second surface 14 and the wall surface 16 at the second end 162. Similar to the angle ⁇ 1, the angle ⁇ 2 may be greater than 90°.
• the numerical range of the angle ⁇ 2 may be the same as the numerical range of the angle ⁇ 1 described above.
• angles ⁇ 1 and ⁇ 2 can be greater than 90°.
• the angles ⁇ 1 and ⁇ 2 being greater than 90° can reduce thermal stress at the first end 161 and the second end 162.
• 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 hole 15 can be enlarged while maintaining the same arrangement pitch as in a conventional through electrode substrate. By enlarging 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 this embodiment, it is possible to improve both the thermodynamic reliability and the electrical characteristics.
• 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.
• the symbol T3 represents the thickness of the third portion 23 of the through electrode 20.
• the thickness T3 of the third portion 23 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 ⁇ m.
• the symbol T4 represents the thickness of the fourth portion 24 of the through electrode 20.
• the thickness T4 of the fourth portion 24 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 ⁇ m.
• Both the thickness T3 and the thickness T4 are dimensions of the through electrode 20 in the planar direction of the first surface 13.
• the uniformity of the thickness of the third portion 23 is evaluated by measuring the thickness of the third portion 23 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 third portion 23 is 0.10 ⁇ m or less, the variation in the thickness of the third portion 23 is determined to be 0.10 ⁇ m or less.
• the thickness T3 is the thickness of the third portion 23 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 the thickness of the third portion 23 measured at a position that is (S3 + 20 ⁇ m) away from the first surface 13 in the thickness direction of the substrate 12.
• the thickness T32 is the thickness of the third portion 23 measured at a position that is (S3 - 20 ⁇ m) away from the first surface 13 in the thickness direction of the substrate 12.
• the thickness uniformity of the fourth portion 24 is also evaluated by measuring the thickness of the fourth 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 T4, T41, and T42 of the fourth portion 24 is 0.10 ⁇ m or less, the thickness variation of the fourth portion 24 is determined to be 0.10 ⁇ m or less.
• the thickness T4 is the thickness of the fourth portion 24 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 the thickness of the fourth portion 24 measured at a position that is (S4 + 20 ⁇ m) away from the second surface 14 in the thickness direction of the substrate 12.
• the thickness T42 is the thickness of the fourth portion 24 measured at a position that is (S4 - 20 ⁇ m) away from the second surface 14 in the thickness direction of the substrate 12.
• the ratio R3/T4 of the minimum dimension R3 to the thickness T4 of the fourth portion 24 is, like the ratio R3/T3, for example, 1.2 or more, and may be 1.5 or more, or 1.8 or more.
• the ratio R3/T4 is, like the ratio R3/T3, for example, 3.0 or less, and may be 2.4 or less, or 2.2 or less.
• the first portion 21 located on the first surface 13 has a thickness T1.
• the thickness T1 of the first portion 21 may be the same as the thickness T3 of the third portion 23.
• the thickness T1 of the first portion 21 may be greater or smaller than the thickness T3 of the third portion 23.
• the second portion 22 located on the second surface 14 has a thickness T2.
• the thickness T2 of the second portion 22 may be the same as the thickness T4 of the fourth portion 24.
• the thickness T2 of the second portion 22 may be greater or less than the thickness T4 of the fourth portion 24.
• the above-mentioned distances and dimensions of the substrate 12 and the through-hole electrode 20 are calculated based on an image of a cross section of the through-hole electrode substrate 10 taken by an electron microscope.
• the cross section is obtained by cutting the through-hole electrode substrate 10 along a cutting plane passing through the center point of the through-hole 15 in a plan view.
• the first conductive layer 35 is a layer having electrical conductivity located on the first surface 13.
• the first conductive layer 35 may be a pad or a wiring.
• the first conductive layer 35 may include a plating layer 201 and a seed layer 202, similar to the first portion 21 of the through electrode 20.
• the second conductive layer 36 is a conductive layer located on the second surface 14.
• the second conductive layer 36 may be a pad or a wiring.
• the second conductive layer 36 may include a plating layer 201 and a seed layer 202, similar to the second portion 22 of the through electrode 20.
• the substrate 12 is prepared. Next, a resist layer is provided on at least one of the first surface 13 and the second surface 14. After that, an opening is provided in the resist layer at a position corresponding to the through hole 15. Next, the substrate 12 is processed at the opening in the resist layer. As a result, the through hole 15 is formed in the substrate 12 as shown in FIG. 5.
• the through hole 15 includes a wall surface 16 extending from the first surface 13 to the second surface 14.
• Methods for processing the substrate 12 include dry etching, wet etching, and the like. Dry etching methods include reactive ion etching, deep digging reactive ion etching, and the like.
• the through holes 15 may be formed in the substrate 12 by irradiating the substrate 12 with a laser.
• the laser may be an excimer laser, an Nd:YAG laser, a femtosecond laser, or the like.
• 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, or the like may be used.
• 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.
• the laser is used not for processing the substrate 12, but for partially forming a modified layer on the first surface 13 and the second surface 14 of the substrate 12.
• the modified layer is preferentially etched compared to other portions.
• 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.
• the through electrode forming step includes a seed layer forming step and a plating layer forming step.
• a seed layer 202 is formed on the first surface 13, the second surface 14, and the wall surface 16 of the substrate 12.
• the seed layer 202 is formed by sputtering.
• the plating layer formation process includes a resist layer formation process, a plating process, and a resist layer removal process.
• FIG. 7 is a cross-sectional view showing an example of the resist layer formation process.
• a first resist layer 41 is partially formed on the seed layer 202 located on the first surface 13
• a second resist layer 42 is partially formed on the seed layer 202 located on the second surface 14.
• the first resist layer 41 and the second resist layer 42 are provided so as to cover the areas of the seed layer 202 where the plating layer 201 is not formed.
• FIG. 8 is a cross-sectional view showing an example of a plating process.
• a plating layer 201 is formed on a seed layer 202 by electrolytic plating.
• the substrate 12 on which the seed layer 202 and the resist layers 41, 42 are formed may be immersed in an electrolytic plating solution.
• a current is passed through the seed layer 202, causing the plating layer 201 to precipitate on the seed layer 202.
• the through hole 15 of the substrate 12 includes a minimum portion 163.
• the plating layer 201 formed along the circumferential direction of the through hole 15 in the minimum portion 163 is connected to each other. That is, as shown in FIG. 8, the through hole 15 is closed by the plating layer 201 in the minimum portion 163. That is, a closed portion 25 is formed.
• the electrolytic plating solution circulates in the first space SP1 and the second space SP2.
• the first space SP1 is a space located between the minimum portion 163 and the first surface 13 in the thickness direction of the substrate 12.
• the second space SP2 is a space located between the minimum portion 163 and the second surface 14 in the thickness direction of the substrate 12.
• the plating process before the through hole 15 in the narrowest portion 163 is closed by the plating layer 201 is also referred to as the first plating process.
• the plating process after the through hole 15 in the narrowest portion 163 is closed by the plating layer 201 is also referred to as the second plating process.
• the plating layer 201 grows in the first space SP1 and the second space SP2.
• the closed portion 25 grows in the thickness direction of the substrate 12.
• the time of the second plating process is adjusted so that the numerical ranges for the above-mentioned first distance K1, second distance K2, thickness T5 of the closed portion 25, etc. are achieved.
• the second plating process is carried out so that the ratio of the thickness T5 of the closed portion 25 to the thickness T0 of the substrate 12 is 0.20 or more and 0.40 or less.
• a resist layer removal process is performed to remove the first resist layer 41 and the second resist layer 42.
• a seed layer removal process is performed to remove a portion of the seed layer 202.
• the seed layer 202 that overlaps the first resist layer 41 and the second resist layer 42 in a plan view is removed. In this manner, the through electrode 20 is obtained.
• a resin layer forming process is performed to form a resin layer 30.
• a layer containing a resin material is formed on the first surface 13 and the second surface 14.
• a resin film including a layer containing a resin material is attached to the first surface 13 and the second surface 14.
• the layer containing the resin material located on the first surface 13 is pushed into the space inside the third portion 23.
• the layer containing the resin material located on the second surface 14 is pushed into the space inside the fourth portion 24.
• the resin material is cured.
• the layer containing the resin material is irradiated with ultraviolet light.
• a first resin layer 31 and a second resin layer 32 are formed as shown in FIG. 11. In this manner, a through electrode substrate 10 including a substrate 12, a through electrode 20, and a resin layer 30 is obtained.
• the through electrode substrate 10 has a through electrode 20 including a first portion 21, a second portion 22, a third portion 23, a fourth portion 24, and a closed portion 25, and a resin layer 30 including a first resin layer 31 and a second resin layer 32.
• This configuration makes it possible to increase the allowable current of the through electrode 20 while suppressing defects such as voids.
• FIG. 12 is a cross-sectional view showing a through electrode substrate according to a first comparative embodiment.
• the through electrode 20 is made of a conductive material that fills the entire through hole 15.
• both the first dimension R1 and the second dimension R2 of the through hole 15 are set large. In this case, the allowable current is sufficiently increased.
• defects such as voids are likely to occur in the plating layer due to the dimension of the plating layer in the planar direction of the first surface 13 becoming too large.
• first dimension R1 and the second dimension R2 of the through hole 15 are limited, defects such as voids are suppressed. However, when the first dimension R1 and the second dimension R2 are limited, the allowable current of the through electrode 20 cannot be sufficiently increased.
• the first dimension R1 becomes too large, there is a concern that defects such as voids will occur in the plating layer. If the first dimension R1 is limited to an extent that does not cause defects such as voids in the plating layer, defects such as voids will be suppressed. However, if the first dimension R1 is limited, the allowable current of the through electrode 20 cannot be sufficiently increased.
• the dimensions of the plating layer in the planar direction of the first surface 13 are limited compared to the first comparative embodiment and the second comparative embodiment. Therefore, in this embodiment, the first dimension R1 and the second dimension R2 of the through hole 15 can be increased while suppressing defects such as voids. In this embodiment, the allowable current of the through electrode 20 can be increased while suppressing defects such as voids.
• FIG. 14 is a cross-sectional view showing a through electrode substrate according to a third comparative embodiment.
• the through electrode 20 includes a plating layer formed on the wall surface 16 of the through hole 15. The space in the through hole where no plating layer is present is filled with a resin material.
• the allowable current of the through electrode 20 is increased by setting the dimension of the through hole 15 in the planar direction of the first surface 13 large or by setting the thickness of the plating layer large.
• both the first dimension R1 and the second dimension R2 of the through hole 15 are set large, and furthermore, the thickness of the plating layer is set large. In this case, the allowable current is sufficiently increased.
• both the first dimension R1 and the second dimension R2 are set large, the space in the through hole where no plating layer exists becomes large. As a result, there is concern that defects such as voids may occur in the resin material.
• FIG. 15 is a cross-sectional view showing a through electrode substrate according to a fourth comparative embodiment.
• the through electrode 20 includes a plating layer formed on the wall surface 16 of the through hole 15, similar to the third comparative embodiment.
• the space in the through hole where there is no plating layer is filled with a resin material.
• only the first dimension R1 of the through hole 15 is set large.
• the closing portion 25 that closes the through hole 15 is formed in the smallest portion 163 located between the first end 161 and the second end 162.
• the size of the space of the through hole where no plating layer is present is smaller than in the third comparative embodiment. Therefore, this embodiment can suppress the occurrence of defects such as voids in the resin layer 30.
• the closing portion 25 is formed in the smallest portion 163 instead of the second end 162
• the dimensions in the thickness direction of the substrate 12 of the spaces SP1 and SP2 in which the electrolytic plating solution circulates are smaller than in the fourth comparative embodiment. Therefore, in this embodiment, the electrolytic plating solution can circulate appropriately even after the closing portion 25 is formed, compared to the fourth comparative embodiment. Therefore, this embodiment can suppress the thickness of the plating layer from varying depending on the position.
• FIG. 16 is a cross-sectional view showing a through electrode substrate according to a fifth comparative embodiment.
• the through electrode 20 includes a plating layer formed on the wall surface 16 of the through hole 15 and a plating layer that closes the through hole 15 at the second end 162.
• the space of the through hole where no plating layer is present is filled with a resin material.
• the allowable current of the through electrode 20 is increased by setting the dimension of the through hole 15 in the planar direction of the first surface 13 large or by setting the thickness of the plating layer large.
• both the first dimension R1 and the second dimension R2 of the through hole 15 are set large, and furthermore, the thickness of the plating layer is set large. In this case, the allowable current is sufficiently increased.
• both the first dimension R1 and the second dimension R2 are set large, the space in the through hole where no plating layer exists becomes large. As a result, there is concern that defects such as voids may occur in the resin material.
• FIG. 17 is a cross-sectional view showing a through electrode substrate according to a sixth comparative embodiment.
• the through electrode 20 includes a plating layer formed on the wall surface 16 of the through hole 15, and a plating layer that closes the through hole 15 at the second end 162, similar to the fifth comparative embodiment.
• the space in the through hole where no plating layer is present is filled with a resin material.
• only the first dimension R1 of the through hole 15 is set large.
• the second end 162 of the through hole 15 is closed by a plating layer during the plating process.
• the circulation of the electrolytic plating solution inside the through hole 15 is inhibited.
• the thickness of the plating layer formed on the wall surface 16 of the through hole 15 is likely to vary depending on the position.
• the closing portion 25 that closes the through hole 15 is formed in the smallest portion 163 located between the first end 161 and the second end 162.
• the size of the space of the through hole where no plating layer is present is smaller than in the fifth comparative embodiment. Therefore, this embodiment can suppress the occurrence of defects such as voids in the resin layer 30.
• the closing portion 25 is formed in the smallest portion 163 instead of the second end 162
• the dimensions in the thickness direction of the substrate 12 of the spaces SP1 and SP2 in which the electrolytic plating solution circulates are smaller than in the sixth comparative embodiment. Therefore, in this embodiment, the electrolytic plating solution can circulate appropriately even after the closing portion 25 is formed, compared to the sixth comparative embodiment. Therefore, this embodiment can suppress the thickness of the plating layer from varying depending on the position.
• the through electrode substrate 10 may include a first surface resin layer 33 located on the first surface 13.
• the first surface resin layer 33 may be integral with the first resin layer 31.
• the first surface resin layer 33 and the first resin layer 31 may be formed from the same resin film in the resin layer formation step.
• a conductive layer 37 connected to the first conductive layer 35 may be formed in an opening formed in the first surface resin layer 33.
• the through electrode substrate 10 may have a second surface resin layer 34 located on the second surface 14.
• the second surface resin layer 34 may be integral with the second resin layer 32.
• the second surface resin layer 34 and the second resin layer 32 may be formed from the same resin film in the resin layer formation process.
• a conductive layer 38 connected to the second conductive layer 36 may be formed in an opening formed in the second surface resin layer 34.
• the through hole electrode substrate 10 may include a semiconductor element.
• the semiconductor element may include a terminal electrically connected to the conductive layer 37.
• the through hole electrode substrate 10 on which the semiconductor element is mounted is also called a mounting substrate.
• the through electrode 20 may not include the first portion 21. That is, the through electrode 20 may not include a portion located on the first surface 13.
• the third portion 23 of the through electrode 20 may include an end face parallel to the first surface 13.
• the end face of the third portion 23 parallel to the first surface 13 is also referred to as the third surface 231.
• the third surface 231 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 ⁇ m or less.
• the through electrode 20 may not include the second portion 22. That is, the through electrode 20 may not include a portion located on the second surface 14.
• the fourth portion 24 of the through electrode 20 may include an end surface parallel to the second surface 14.
• the end surface of the fourth portion 24 parallel to the second surface 14 is also referred to as the fourth surface 241.
• the fourth surface 241 may be located on the same plane as the second surface 14.
• a through hole 15 is formed in the substrate 12.
• a seed layer 202 is formed on the first surface 13, the second surface 14, and the wall surface 16 of the substrate 12.
• a plating process is carried out.
• a plating layer 201 is formed on the seed layer 202 by electrolytic plating.
• the plating layer 201 may be formed on the entire area of the seed layer 202.
• the plating process includes a first plating process shown in FIG. 25 and a second plating process shown in FIG. 26. The second plating process is adjusted so that the numerical ranges for the above-mentioned first distance K1, second distance K2, thickness T5 of the closing portion 25, etc. are realized.
• a resin layer formation process may be carried out.
• a first resin layer 31 is formed in the first space SP1
• a second resin layer 32 is formed in the second space SP2.
• the first resin layer 31 may also be formed on the plating layer 201 on the first surface 13.
• the second resin layer 32 may also be formed on the plating layer 201 on the second surface 14.
• the polishing process may include at least one of a first polishing process and a second polishing process.
• the polishing process includes a first polishing process and a second polishing process.
• the first polishing process the seed layer 202 and the plating layer 201 located on the first surface 13 are removed by polishing.
• the second polishing process the seed layer 202 and the plating layer 201 located on the second surface 14 are removed by polishing.
• the polishing is, for example, chemical mechanical polishing.
• the first polishing process forms the third surface 231 on the third portion 23.
• the second polishing process forms the fourth surface 241 on the fourth portion 24.
• the through electrode 20 includes a third portion 23, a fourth portion 24, and a closed portion 25, and the resin layer 30 includes a first resin layer 31 and a second resin layer 32.
• the dimensions of the plating layer in the planar direction of the first surface 13 are limited. Therefore, in this modified example, the first dimension R1 and the second dimension R2 of the through hole 15 can be increased while suppressing the occurrence of defects such as voids in the resin layer 30.
• the third portion 23 may include a curved surface 232 in the cross-sectional view.
• the curved surface 232 is in contact with the first resin layer 31.
• the curved surface 232 is connected to a surface of the third portion 23 parallel to the first surface 13.
• the curved surface 232 is connected to the third surface 231.
• the curved surface 232 may have a normal direction parallel to the thickness direction of the substrate 12 at a position where the curved surface 232 and the third surface 231 are connected.
• the through electrode 20 includes a surface that extends along the wall surface 16 and a surface that is parallel to the first surface 13. If the direction in which the surface extends changes suddenly at the boundary between these two surfaces, it is possible that the thermodynamic reliability or high-frequency electrical characteristics of the through electrode 20 will decrease.
• the boundary between the surface of the third portion 23 that extends along the wall surface 16 and the third surface 231 is the curved surface 232.
• the direction in which the surface of the third portion 23 extends changes gently and continuously. Therefore, this modified example can improve the thermodynamic reliability or high-frequency electrical characteristics of the through electrode 20.
• the symbol T31 represents the width of the third surface 231.
• the width T31 is the dimension of the third surface 231 in the in-plane direction of the first surface 13. Because the third portion 23 includes the curved surface 232, the width T31 is smaller than the thickness T3 of the third portion 23.
• the ratio of the width T31 to the thickness T3, T31/T3, is, for example, 0.90 or less, may be 0.80 or less, or may be 0.70 or less.
• T31/T3 is, for example, 0.10 or more, may be 0.30 or more, or may be 0.50 or more.
• the fourth portion 24 may include a curved surface 242 in a cross-sectional view.
• the curved surface 242 is in contact with the second resin layer 32.
• the curved surface 242 is connected to a surface of the fourth portion 24 that is parallel to the second surface 14. In the example shown in FIG. 29, the curved surface 242 is connected to the fourth surface 241.
• the curved surface 242 can also improve the thermodynamic reliability or high-frequency electrical properties of the through electrode 20.
• T41 denotes the width of the fourth surface 241.
• the width T41 is the dimension of the fourth surface 241 in the in-plane direction of the second surface 14. Because the fourth portion 24 includes the curved surface 242, the width T41 is smaller than the thickness T4 of the fourth portion 24.
• the numerical range of T41/T4, which is the ratio of the width T41 to the thickness T4, may be the numerical range described above for T31/T3.
• a through hole 15 is formed in the substrate 12.
• a seed layer 202 is formed on the first surface 13, the second surface 14, and the wall surface 16 of the substrate 12.
• a plating process is carried out.
• a polishing step may be performed.
• the polishing step may include at least one of a first polishing step and a second polishing step.
• the polishing step includes a first polishing step and a second polishing step.
• the polishing is, for example, chemical mechanical polishing.
• the first polishing process may be performed before the first resin layer 31 is formed in the first space SP1. Since the first resin layer 31 is not formed in the first space SP1, the boundary portion between the surface of the third portion 23 extending along the wall surface 16 and the third surface 231 is polished to generate the curved surface 232.
• the second polishing process may be performed before the second resin layer 32 is formed in the second space SP2. Since the second resin layer 32 is not formed in the second space SP2, the boundary portion between the surface of the fourth portion 24 extending along the wall surface 16 and the fourth surface 241 is polished to generate the curved surface 242.
• the through electrode 20 includes a third portion 23, a fourth portion 24, and a closed portion 25, and the resin layer 30 includes a first resin layer 31 and a second resin layer 32.
• the dimensions of the plating layer in the planar direction of the first surface 13 are limited. Therefore, in this modified example, the first dimension R1 and the second dimension R2 of the through hole 15 can be increased while suppressing the occurrence of defects such as voids in the resin layer 30.
• (Fifth Modification) 32 is a cross-sectional view showing a through electrode substrate 10 in a fifth modified example.
• a part of the wall surface 16 of the through hole 15 may include a curved surface 164 in the cross-sectional view.
• the curved surface 164 is connected to a first end 161.
• the curved surface 164 may have a normal direction at the first end 161 that is parallel to the thickness direction of the substrate 12.
• the substrate 12 includes a wall surface 16 and a first surface 13. If the angle at which the surfaces extend changes suddenly at the boundary between these two surfaces, it is possible that the thermodynamic reliability or high-frequency electrical characteristics of the through-hole electrode substrate 10 will decrease.
• the portion of the wall surface 16 that is connected to the first surface 13 is a curved surface 164.
• the angle at which the surface of the substrate 12 extends changes gently and continuously. Therefore, this modified example can improve the thermodynamic reliability or high-frequency electrical characteristics of the through electrode substrate 10.
• the surface of the third portion 23 has a shape that follows the wall surface 16. Because the wall surface 16 includes a curved surface 164, the third portion 23 can also include a curved surface 232. In this modification, the curved surface 232 is connected to a surface of the first portion 21 that is parallel to the first surface 13. In the curved surface 232, the direction in which the surface of the third portion 23 extends changes gently and continuously. Therefore, this modification can improve the thermodynamic reliability or high-frequency electrical characteristics of the through electrode 20.
• a portion of the wall surface 16 of the through hole 15 may include a curved surface 165 connected to the second end 162 in a cross-sectional view.
• the curved surface 165 may have a normal direction at the second end 162 that is parallel to the thickness direction of the substrate 12.
• the fourth portion 24 can also include a curved surface 242.
• the curved surface 242 is connected to a surface of the second portion 22 that is parallel to the second surface 14.
• the direction in which the surface of the fourth portion 24 extends changes gently and continuously. Therefore, this modification can improve the thermodynamic reliability or high-frequency electrical characteristics of the through electrode 20.
• Fig. 33 is a cross-sectional view showing the through electrode substrate 10 in the sixth modified example.
• Fig. 34 is a plan view showing the through electrode substrate 10 in the sixth modified example.
• the third portion 23 of the through electrode 20 includes a third surface 231, similar to the third and fourth modified examples.
• the through electrode substrate 10 may include a first surface resin layer 33 located on the first surface 13.
• the first surface resin layer 33 may be in contact with the first surface 13.
• the first surface resin layer 33 includes an opening 331 penetrating the first surface resin layer 33 and an opening end 332.
• the opening end 332 defines the outline of the opening 331 in a plan view.
• the first end 161 of the wall surface 16 defines the boundary between the wall surface 16 and the third portion 23 in a plan view.
• the opening end 332 may be located at least partially inside the first end 161.
• the first surface resin layer 33 at least partially overlaps the boundary between the wall surface 16 and the third portion 23 in a plan view.
• First surface resin layer 33 does not overlap the entire area of third surface 231.
• opening end 332 may surround a portion of third surface 231 in a plan view, as shown in FIG. 34. In this case, a portion of third surface 231 located inside opening end 332 is exposed to opening 331.
• a conductive layer may be connected to the portion of third surface 231 exposed to opening 331.
• the first surface resin layer 33 contains an insulating resin material.
• the resin material is an organic material such as polyimide, epoxy, acrylic, or polyphenyl ether.
• the first surface resin layer 33 has a thickness T7.
• the thickness T7 is, for example, 1.0 ⁇ m or more, and may be 2.0 ⁇ m or more, or 3.0 ⁇ m or more.
• the thickness T7 is, for example, 20.0 ⁇ m or less, and may be 15.0 ⁇ m or less, or 8.0 ⁇ m or less.
• the fourth portion 24 of the through electrode 20 may include a fourth surface 241, as in the third and fourth modified examples.
• the through electrode substrate 10 may include a second surface resin layer 34 located on the second surface 14.
• the second surface resin layer 34 may be in contact with the second surface 14.
• the second surface resin layer 34 includes an opening 341 penetrating the second surface resin layer 34 and an opening end 342.
• the opening end 342 defines the outline of the opening 341 in a plan view.
• the opening end 342 may be located at least partially inside the second end 162.
• the second surface resin layer 34 at least partially overlaps the boundary between the wall surface 16 and the fourth portion 24 in a plan view.
• the entire area of the opening end 342 may be located inside the second end 162.
• the second surface resin layer 34 overlaps the entire area of the boundary between the wall surface 16 and the fourth portion 24 in a plan view.
• the second surface resin layer 34 does not overlap the entire fourth surface 241.
• the opening end 342 may surround a portion of the fourth surface 241 in a plan view. In this case, the portion of the fourth surface 241 located inside the opening end 342 is exposed to the opening 341.
• a conductive layer may be connected to the portion of the fourth surface 241 exposed to the opening 341.
• the second surface resin layer 34 contains an insulating resin material, similar to the first surface resin layer 33.
• the second surface resin layer 34 has a thickness T8.
• the numerical range of thickness T8 may be the same as the numerical range described above for thickness T7.
• the conductive layer 37 may overlap the first resin layer 31 in a planar view. Although not shown, the conductive layer 37 does not have to overlap the entire area of the first resin layer 31 in a planar view.
• the through electrode substrate 10 may include a conductive layer 38 located in the opening 341 of the second surface resin layer 34.
• the conductive layer 38 may be in contact with the fourth surface 241 of the fourth portion 24.
• the conductive layer 38 may overlap the second resin layer 32 in a planar view. Although not shown, the conductive layer 38 does not have to overlap the entire area of the second resin layer 32 in a planar view.
• the manufacturing method for the through-hole electrode substrate 10 is explained.
• a process is carried out to form a through electrode 20 having a third portion 23 including a third surface 231.
• the through electrode 20 may have a fourth portion 24 including a fourth surface 241.
• a process of forming a first-side resin layer 33 on the first surface 13 is carried out.
• a solution containing a resin material such as polyimide and a solvent is applied onto the first surface 13.
• a drying process is carried out to evaporate the solvent.
• a process of forming an opening 331 in the first-side resin layer 33 is carried out.
• the opening 331 is formed in the first-side resin layer 33 by photolithography.
• a second surface resin layer 34 including an opening 341 may be formed on the second surface 14.
• a seed layer 371 is formed in the opening 331 of the first surface resin layer 33.
• the seed layer 371 is formed by sputtering.
• the seed layer 371 contacts the third surface 231 of the third portion 23.
• the seed layer 371 may also be formed on the first surface resin layer 33.
• a seed layer 381 may also be formed in the opening 341 of the second surface resin layer 34 and on the second surface resin layer 34.
• a resist layer 43 is formed on the seed layer 371.
• the resist layer 43 is provided so as to cover the areas of the seed layer 371 other than the area corresponding to the conductive layer 37.
• a resist layer 44 may be formed on the seed layer 381.
• the resist layer 44 is provided so as to cover the areas of the seed layer 381 other than the area corresponding to the conductive layer 38.
• a plating layer 372 is formed on the seed layer 371 by electrolytic plating.
• a plating layer 382 may be formed on the seed layer 381 by electrolytic plating.
• the resist layer 43 is removed.
• the seed layer 371 that overlaps the resist layer 43 in a plan view is removed.
• a conductive layer 37 is obtained that includes the seed layer 371 and the plating layer 372 and is connected to the third portion 23.
• Gas may be generated during the manufacturing process of the through electrode substrate 10.
• gas is generated from the through electrode 20.
• gas is generated from a resin material such as the resin layer 30.
• the gas may be, for example, water vapor.
• the gas is generated, for example, during the process of heating the components of the through electrode substrate 10.
• the gas remains in the gaps inside the through electrode substrate 10.
• the gas remains in the gap between the wall surface 16 and the through electrode 20. If the gas continues to remain in the gaps inside the through electrode substrate 10, there is a concern that deformation, damage, etc. may occur inside the through electrode substrate 10 due to the gas pressure.
• the through electrode substrate 10 includes a first surface resin layer 33 that overlaps the boundary between the wall surface 16 and the third portion 23.
• the molecular structure of the resin material that constitutes the first surface resin layer 33 is larger than the molecular structure of a gas such as water vapor. Gas in the gap between the wall surface 16 and the third portion 23 passes through the first surface resin layer 33 and is released to the outside of the through electrode substrate 10. Therefore, deformation, damage, etc., occurring inside the through electrode substrate 10 is suppressed.
• the molecular structure of the resin material constituting the second surface resin layer 34 is larger than the molecular structure of gases such as water vapor. Gas in the gap between the wall surface 16 and the fourth portion 24 passes through the second surface resin layer 34 and is released to the outside of the through-hole electrode substrate 10. Therefore, deformation, damage, etc., occurring inside the through-hole electrode substrate 10 is suppressed.
• FIG. 19 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, it 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, etc.
• Example 1 A glass substrate having a thickness T0 of 400 ⁇ m was prepared as the substrate 12. Then, a through hole 15 was formed in the substrate 12. The through hole 15 includes 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 have a circular outline in a plan view. The first dimension R1, the second dimension R2, and the minimum dimension R3 were 150 ⁇ m, 150 ⁇ m, and 60 ⁇ m, respectively.
• the through electrode 20 includes a first portion 21, a second portion 22, a third portion 23, a fourth portion 24, and a closed portion 25.
• the thickness T3 of the third portion 23 and the thickness T4 of the fourth portion 24 were both 30 ⁇ m.
• the distance from the first surface 13 to the closed portion 25 in the thickness direction of the substrate 12, i.e., the first distance K1 was 150 ⁇ m.
• the distance from the second surface 14 to the closed portion 25 in the thickness direction of the substrate 12, i.e., the second distance K2 was 150 ⁇ m.
• the thickness T5 of the closed portion 25 in the thickness direction of the substrate 12 was 100 ⁇ m.
• the ratio K1/T0 of the first distance K1 to the thickness T0 of the substrate 12 is 0.375.
• the ratio K2/T0 of the second distance K2 to the thickness T0 of the substrate 12 is 0.375.
• the ratio T5/T0 of the thickness T5 of the closed portion 25 to the thickness T0 of the substrate 12 is 0.25.
• the maximum value of the current that can be passed through the through electrode 20 of the through electrode substrate 10 of Example 1 was measured.
• the maximum value of the current is also called the allowable current.
• the allowable current was 0.90 A.
• the allowable current is the current value that causes a temperature rise of 10°C in the through electrode 20.
• the temperature rise is the difference between the temperature of the through electrode 20 when no current is flowing and the temperature of the through electrode 20 when an allowable current is flowing.
• the allowable current was calculated by measuring the temperature of the through electrode 20 while changing the current value passed through the through electrode 20. The temperature of the through electrode 20 was measured 10 minutes after the current value was changed.
• An I-V meter SPST-A1A manufactured by Togami Denki was used as the device for passing a current through the through electrode 20.
• a thermograph was used as the device for measuring the temperature of the through electrode 20.
• An infrared camera Optris PI 450 was used as the thermograph.
• the reliability of the through electrode substrate 10 of Example 1 was evaluated.
• the through electrode substrate 10 was subjected to 1000 thermal cycles, and then the appearance of the through electrode substrate 10 was observed. No defects such as cracks were observed in the appearance of the through electrodes 20 of the through electrode substrate 10.
• One thermal cycle includes a temperature increase process, a high-temperature holding process, a temperature decrease process, and a low-temperature holding process.
• the temperature increase process is a process in which the ambient environment of the through electrode substrate 10 is changed from -55°C to +125°C for 30 minutes.
• the high-temperature holding process is a process in which the ambient environment of the through electrode substrate 10 is held at +125°C for 30 minutes.
• the temperature increase process is a process in which the ambient environment of the through electrode substrate 10 is changed from +125°C to -55°C for 30 minutes.
• the low-temperature holding process is a process in which the ambient environment of the through electrode substrate 10 is held at -55°C for 30 minutes.
• Example 2 to 12 The through electrode substrate 10 was fabricated by changing any one of the values of the first dimension R1, the second dimension R2, and the minimum dimension R3 of the through hole 15, and the first distance K1, the second distance K2, or the thickness T5 of the through electrode 20 from the values in Example 1. Then, similarly to the case of Example 1, the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated. The results are shown in FIG.
• the through electrode substrate 10 was fabricated by changing any one of the values of the first dimension R1, the second dimension R2, and the minimum dimension R3 of the through hole 15, and the first distance K1, the second distance K2, or the thickness T5 of the through electrode 20 from the values in Example 1. Then, similarly to the case of Example 1, the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated. The results are shown in FIG.
• Comparative Example 1 when the minimum dimension of the minimum portion 163 was 55 ⁇ m or less, the volume of the through electrode 20 was insufficient, and the allowable current was less than 0.80 A. As can be seen from Comparative Example 2, when the minimum dimension of the minimum portion 163 was 70 ⁇ m or more, a closed portion 25 was not formed in the minimum portion 163, and the allowable current was less than 0.80 A. In Examples 1 to 12, the minimum dimension of the minimum portion 163 was greater than 55 ⁇ m and less than 70 ⁇ m, so an allowable current of 0.80 A or more was achieved.
• the through electrode substrate 10 was fabricated by changing the value of either the minimum dimension R3 of the through hole 15 or the thickness T3 or thickness T5 of the through electrode 20 from the value in Example 1. Then, similarly to the case of Example 1, the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated. The results are shown in FIG.
• the through electrode substrate shown in FIG. 12 was produced.
• the first dimension R1 and the second dimension R2 were 108 ⁇ m.
• the substrate 12 was a glass substrate having a thickness T0 of 400 ⁇ m, as in Example 1.
• the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated.
• the allowable current was 1.1 A.
• the reliability evaluation result was NG.
• the allowable current is calculated based on the results of a simulation simulating heat dissipation of the through electrode substrate 10.
• the simulation conditions are as follows. In the simulation, a heat dissipation path is assumed in which heat generated in the through electrode 20 is released from the first portion 21 of the through electrode 20 to the atmosphere by convection.
• Thermal conductivity of substrate 12 1.4 [W/m ⁇ K]
• Thermal conductivity of the through electrode 20 400 [W/m ⁇ K]
• ⁇ Resistivity of through electrode 20 1.68 ⁇ 10 ⁇ 8 [ ⁇ m]
• Thermal conductivity of resin layer 30 0.25 [W/m ⁇ K]
• Area of the first portion 21 of the through electrode 20 500 ⁇ m ⁇ 500 ⁇ m
• Thickness of the first portion 21 of the through electrode 20 18 ⁇ m Heat transfer coefficient between the through electrode 20 and the atmosphere: 373 [W/ m2 ⁇ K]
• the heat transfer coefficient of 373 [W/ m2 ⁇ K] was calculated based on the heat dissipation characteristics of the wiring board described in JIS C 5012:1993.
• the wiring board includes a substrate made of FR4 and a conductive layer located on the substrate.
• the configuration of the wiring board is as follows. Thermal conductivity of substrate: 0.3 [W/mK] Substrate thickness: 400 ⁇ m Thermal conductivity of conductive layer: 400 [W/mK] Conductive layer resistivity: 1.68 ⁇ 10 ⁇ 8 [ ⁇ m] Conductive layer area: 500 ⁇ m ⁇ 500 ⁇ m Conductive layer thickness: 18 ⁇ m
• the target characteristics of the wiring board are as follows.
• the heat transfer coefficient that can achieve the target characteristics is 373 [W/ m2 ⁇ K]. Based on this result, the heat transfer coefficient of 373 [W/ m2 ⁇ K] was also adopted in this embodiment. Allowable current of conductive layer: 1 [A] Temperature rise of conductive layer: 10°C
• the through electrode substrate shown in FIG. 13 was produced.
• the first dimension R1 and the second dimension R2 were 85 ⁇ m and 50 ⁇ m, respectively.
• the substrate 12 was a glass substrate having a thickness T0 of 400 ⁇ m, as in Example 1.
• the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated.
• the allowable current was 0.65 A.
• the reliability evaluation result was good.
• the through electrode substrate shown in FIG. 14 was produced.
• the first dimension R1 and the second dimension R2 were 108 ⁇ m.
• the thickness of the plating layer was 30 ⁇ m.
• the substrate 12 was a glass substrate having a thickness T0 of 400 ⁇ m, as in Example 1.
• the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated.
• the allowable current was 1.1 A.
• the reliability evaluation result was NG.
• the through electrode substrate shown in FIG. 15 was produced.
• the first dimension R1 and the second dimension R2 were 85 ⁇ m and 50 ⁇ m, respectively.
• the thickness of the plating layer was 18 ⁇ m.
• the substrate 12 was a glass substrate having a thickness T0 of 400 ⁇ m, as in Example 1.
• the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated.
• the allowable current was 0.60 A. The reliability evaluation result was good.
• the through electrode substrate shown in FIG. 16 was produced.
• the first dimension R1 and the second dimension R2 were 108 ⁇ m.
• the thickness of the plating layer was 30 ⁇ m.
• the substrate 12 was a glass substrate having a thickness T0 of 400 ⁇ m, as in Example 1.
• the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated.
• the allowable current was 1.1 A.
• the reliability evaluation result was NG.
• the through electrode substrate shown in FIG. 17 was produced.
• the first dimension R1 and the second dimension R2 were 85 ⁇ m and 50 ⁇ m, respectively.
• the thickness of the plating layer was 18 ⁇ m.
• the substrate 12 was a glass substrate having a thickness T0 of 400 ⁇ m, as in Example 1.
• the allowable current of the through electrode substrate 10 was measured and the reliability of the through electrode substrate 10 was evaluated.
• the allowable current was 0.60 A.
• the reliability evaluation result was good.
• a through electrode substrate 10 was designed, which includes a through electrode 20 shown in FIG. 12 formed in a through hole 15 not including a minimum portion 163, and a copper plate located on the surface of the substrate 12.
• the through electrode 20 shown in FIG. 12 is also called a filled via.
• the substrate 12 is made of FR4 and has a thickness T0 of 400 ⁇ m.
• the copper plate has a width of 0.5 mm and a thickness of 18 ⁇ m.
• a simulation was performed to simulate the heat dissipation of the through electrode substrate 10. In the simulation, the finite element method was used. In the simulation, it was assumed that heat is dissipated by convection on the surface of the copper plate.
• the heat flux formula is as follows:
• q is the heat flux.
• the unit of the heat flux q is W/ m2 .
• h is the thermal conductivity in convection.
• the unit of the thermal conductivity h is W/ m2 ⁇ K.
• T Cu is the temperature of the copper plate.
• T air is the temperature of the air.
• the value of the thermal conductivity h is 373 [W/ m2 ⁇ K], as in the case of Comparative Examples 13 to 18. This value was calculated based on the heat dissipation characteristics of the wiring board described in JIS C 5012:1993.
• the first dimension R1 and the second dimension R2 were calculated when the through electrode substrate 10 of Comparative Example A1 satisfied the condition for current resistance.
• the condition for current resistance is that "when a direct current of 1 A flows through the through electrode 20, the temperature rise occurring in the through electrode 20 is 10°C or less.” This condition for current resistance is stricter than the judgment condition for the allowable current in Figures 20 and 21 described above.
• the test for passing a current through the through electrode 20 and measuring the temperature is carried out based on JIS C 5012:1993. Current is passed through the through electrode 20 until the temperature stabilizes.
• the thermal stress generated between the substrate 12 and the filled via was calculated based on a simulation when the first dimension R1 and the second dimension R2 were 94 ⁇ m, the value of the current flowing through the copper plate and the filled via was 0.96 A, and the temperature of the through electrode substrate 10 was 260° C.
• the thermal stress at the first end 161 of the through hole 15 showed a maximum value of 187 MPa.
• a through electrode substrate 10 was designed, which includes a through electrode 20 shown in Fig. 14 formed in a through hole 15 not including a thin portion 163, and a copper plate located on the surface of a substrate 12.
• the through electrode 20 shown in Fig. 14 is also called a conformal via.
• the first dimension R1 and second dimension R2 and the thickness of the through electrode 20 on the wall surface 16 were calculated based on a simulation when the through electrode substrate 10 of Comparative Example A2 satisfies the above-mentioned current resistance condition.
• the temperature rise is 10° C. and the value of the current flowing through the copper plate and conformal via is 0.97 A. Therefore, it is presumed that the above-mentioned current resistance condition is satisfied when the first dimension R1 and second dimension R2 are 104 ⁇ m or more and the thickness of the through electrode 20 on the wall surface 16 is 30 ⁇ m or more.
• the thermal stress generated between the substrate 12 and the conformal via was calculated based on a simulation when the first dimension R1 and the second dimension R2 were 104 ⁇ m, the thickness of the through electrode 20 on the wall surface 16 was 30 ⁇ m, the value of the current flowing through the copper plate and the filled via was 0.97 A, and the temperature of the through electrode substrate 10 was 260°C. At the first end 161 of the through hole 15, the thermal stress showed a maximum value of 171 MPa.
• a through electrode substrate 10 was designed, which includes a through electrode 20 shown in FIG. 4 formed in a through hole 15 including a thin portion 163, and a copper plate located on the surface of a substrate 12.
• the first dimension R1, the second dimension R2, the minimum dimension R3, and the thicknesses of the third portion 23 and the fourth portion 24 were calculated based on a simulation when the through electrode substrate 10 of Example A1 satisfies the above-mentioned current resistance condition.
• the first dimension R1 and the second dimension R2 are 180 ⁇ m
• the minimum dimension R3 is 60 ⁇ m
• the thickness T3 of the third portion 23 and the thickness T4 of the fourth portion 24 are 30 ⁇ m
• the temperature rise is 10° C.
• the value of the current flowing through the copper plate and the through electrode 20 is 0.96 A.
• the above-mentioned current resistance condition is satisfied when the first dimension R1 and the second dimension R2 are 180 ⁇ m or more, the minimum dimension R3 is 60 ⁇ m or more, and the thickness T3 of the third portion 23 and the thickness T4 of the fourth portion 24 are 30 ⁇ m or more.
• the thermal stress generated between the substrate 12 and the through electrode 20 was calculated based on a simulation when the first dimension R1 and the second dimension R2 were 180 ⁇ m, the minimum dimension R3 was 60 ⁇ m, the thickness T3 of the third portion 23 and the thickness T4 of the fourth portion 24 were 30 ⁇ m, the value of the current flowing through the copper plate and the through electrode 20 was 0.96 A, and the temperature of the through electrode substrate 10 was 260° C.
• the thermal stress at the first end 161 of the through hole 15 showed a maximum value of 93 MPa.
• Example A1 The maximum value of the thermal stress in Example A1 was approximately half of the maximum value of the thermal stress in Comparative Examples A1 and A2. In the example shown in Example A1, since the through hole 15 includes the minimum portion 163, the angles ⁇ 1 and ⁇ 2 are larger than 90°, and it is believed that the thermal stress was reduced.

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