JP2012099518A - Through-hole electrode substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that when a through-hole electrode is narrowed down, it becomes difficult to fill a through-hole opened in a substrate with a metallic material, and that when a metallic component large in cubic volume is filled in a substrate, mechanical destruction due to a difference in thermal expansion coefficients occurs more easily.SOLUTION: A multilayer film including a first conductive layer is formed on a first surface of a substrate. A concavity is formed from a second surface of the substrate, opposite to the first surface, toward the inside thereof but not reaching the first surface. A through-hole is formed from the bottom face of the concavity until it reaches the first surface. The through-hole is narrower than the concavity. A second conductive film is buried inside the through-hole. The second conductive film is connected to the first conductive film to cover the side and the bottom faces of the concavity, but not completely covering the concavity.

Description

  The present invention relates to a through electrode substrate having an electrode penetrating from one surface of the substrate to the other surface.

  In recent years, integration of semiconductor chips has shifted from two dimensions to three dimensions. In order to electrically connect the stacked semiconductor chips, a through electrode penetrating the semiconductor substrate is formed. A through electrode in which a part on the element forming surface side is made thinner than a part on the back side is known. By narrowing a part of the element formation surface side, the degree of integration of the wiring in the vicinity of the through electrode can be improved.

JP 2005-294577 A JP 2008-21739 A

  The through electrode has a larger volume than elements and wirings formed on the semiconductor substrate. For this reason, the usage-amount of the metal material which forms a penetration electrode increases, and the cost of material will rise. When the through electrode is made thin, it becomes difficult to bury the through hole formed in the substrate with a metal material. Further, when a metal member having a large volume is embedded in the substrate, mechanical breakdown is likely to occur due to a difference in thermal expansion coefficient.

According to one aspect of the invention,
A substrate,
A laminated film formed on the first surface of the substrate and including a first conductive film;
A concave portion that is formed from the second surface opposite to the first surface of the substrate toward the inside, and does not reach the first surface;
A through hole that reaches from the bottom surface of the recess to the first surface, and is thinner than the recess;
A through electrode substrate having a second conductive film embedded in the through hole and connected to the first conductive film, covering a side surface and a bottom surface of the concave portion, but not completely filling the concave portion. Provided.

  By making the through hole narrower than the concave portion, it is possible to reduce the deformation of the laminated film caused by the stress caused by the difference in the thermal expansion coefficient between the second conductive film, the substrate, and the laminated film. By forming the recess, the aspect ratio of the through hole can be reduced as compared with the case where the through hole having a uniform thickness is formed. Thereby, the filling of the second conductive film can be easily performed. In addition, since the recess is not completely filled with the second conductive film, the amount of the material used for the second conductive film can be reduced.

(1A) is a sectional view of a through electrode substrate according to an example, and (1B) and (1C) are sectional views taken along one-dot chain lines 1B-1B and 1C-1C, respectively (1A). (2A) to (2B) are cross-sectional views of the through electrode substrate according to the embodiment in the course of manufacturing. (2C) to (2D) are cross-sectional views of the through electrode substrate according to the embodiment in the course of manufacturing. (2E) to (2F) are cross-sectional views of the through electrode substrate according to the embodiment in the course of manufacturing. (2G) to (2H) are cross-sectional views of the through electrode substrate according to the embodiment in the course of manufacturing. (2I) to (2J) are cross-sectional views of the through electrode substrate according to the embodiment in the course of manufacturing. (2K) to (2M) are cross-sectional views of the through electrode substrate according to the embodiment in the course of manufacturing. (3A) to (3D) are cross-sectional views of samples A to D to be evaluated. (3E) to (3G) are cross-sectional views of samples E to G to be evaluated, and (3Ga) is a cross-sectional plan view of a through-hole portion of the sample G. (4A) is a cross-sectional view of the sample showing the definition of the deformation amount, and (4B) is a graph showing the evaluation results. It is sectional drawing of the penetration electrode substrate by the modification of an Example. It is sectional drawing of the penetration electrode substrate by the other modification of an Example.

  FIG. 1A shows a partial cross-sectional view of a through electrode substrate according to an embodiment. The through electrode substrate is applied to, for example, a CMOS-LSI, a semiconductor memory, a sensor element, a micro electro mechanical system (MEMS) element, and the like.

  An element isolation insulating film 11 is formed on the surface of a semiconductor substrate 10 such as silicon. A transistor 13 is formed in an active region defined by the element isolation insulating film 11. The surface of the element isolation insulating film 11 is referred to as the “first surface 10A” of the substrate 10. A surface opposite to the first surface 10A of the substrate 10 is referred to as a “second surface 10B”.

  On the first surface 10 </ b> A of the substrate 10, a laminated film 14 including multilayer wiring is formed. The laminated film 14 includes a first conductive film (land) 18 disposed directly on the first surface 10A. An electrode pad 15 and a protective film 16 are formed on the laminated film 14. The electrode pad 15 is exposed in the opening formed in the protective film 16.

  A recess 20 is formed from the second surface 10B of the substrate 10 toward the inside of the substrate 10. The recess 20 does not reach the first surface 10A. At least one through hole 21 extending from the bottom surface of the recess 20 to the first surface 10A is formed. The through hole 21 is thinner than the recess 20.

  The second surface 10B of the substrate 10, the side and bottom surfaces of the recess 20, and the side surfaces of the through holes 21 are covered with an insulating film 25 such as silicon oxide. A second conductive film 28 is filled in the through hole 21 and further covers the side surface and the bottom surface of the recess 20. However, the recess 20 is not completely filled with the second conductive film 28. The second conductive film 28 is electrically connected to the first conductive film 18. The surface shape of the second conductive film 28 reflects the shape of the side surface and the bottom surface of the recess 20. Furthermore, the second conductive film 28 covers a partial region of the second surface 10B that is in contact with the edge of the opening of the recess 20. The second conductive film 28 on the second surface 10B constitutes the land 28A.

  The second conductive film 28 includes a seed layer 26 and a plating film 27 that covers the seed layer 26. The seed layer 26 is used as an electrode during electroplating for forming the plating film 27. Copper or a copper alloy is used for the seed layer 26 and the plating film 27.

  A protective film 40 is formed on the insulating film 25 and the second conductive film 28. An opening for exposing the land 28 </ b> A is formed in the protective film 40. A bump 41 is disposed on the land 28A exposed in the opening. The surface shape of the protective film 40 also reflects the shape of the side surface and the bottom surface of the recess 20.

  FIG. 1B is a cross-sectional view taken along one-dot chain line 1B-1B in FIG. 1A. A cross-sectional view taken along one-dot chain line 1A-1A in FIG. 1B corresponds to FIG. 1A. The insulating film 25, the seed layer 26, the plating film 27, and the protective film 40 are laminated in this order on the side surface of the recess 20 having a substantially circular planar shape. A cavity remains inside the protective film 40.

  FIG. 1C shows a cross-sectional view taken along one-dot chain line 1C-1C in FIG. 1A. A cross-sectional view taken along one-dot chain line 1A-1A in FIG. 1C corresponds to FIG. 1A. At least one through hole 21 is disposed on the bottom surface of the recess 20. FIG. 1C shows an example in which five through holes 21 are arranged. A seed layer 26 is formed on the side surface of the through hole 21, and the remaining portion is filled with a plating film 27.

  Next, with reference to FIGS. 2A to 2M, a method for manufacturing the through electrode substrate according to the above embodiment will be described.

  As shown in FIG. 2A, the element isolation insulating film 11 and the transistor 13 are formed on the surface of the substrate 10. On the surface of the element isolation insulating film 11 (first surface 10 </ b> A of the substrate 10), a laminated film 14 including multilayer wiring, an electrode pad 15, and a protective film 16 are formed. The laminated film 14 includes a first conductive film 18 formed directly on the element isolation insulating film 11. The protective film 16 is opposed to the glass handle wafer 30 and the substrate 10 is bonded to the glass handle wafer 30 using, for example, an organic temporary adhesive.

  As shown in FIG. 2B, the thickness of the substrate 10 is reduced to, for example, 200 μm by grinding the substrate 10 from the second surface 10B (back surface).

  As shown in FIG. 2C, a photoresist film 31 is formed on the second surface 10B of the substrate 10. An opening 31A is formed by exposing and developing the photoresist film 31. The opening 31A has a planar shape corresponding to the recess 20 (FIG. 1A). The diameter of the opening 31A is, for example, 200 μm.

As shown in FIG. 2D, the recess 20 is formed by etching the substrate 10 using the resist film 31 as an etching mask. When the substrate 10 is silicon, for example, reactive ion etching (RIE) using SF ₆ and C ₄ F ₈ can be applied to the etching of the substrate 10. The etching rate of silicon is, for example, 20 μm / min, and the depth of the recess 20 can be adjusted by controlling the etching time. The depth of the recess 20 is, for example, 150 μm. After forming the recess 20, the resist film 31 is removed.

  As shown in FIG. 2E, a photoresist film 33 is formed on the second surface 10B of the substrate 10 and the side and bottom surfaces of the recess 20. For example, nanospray coating is applied to the formation of the photoresist film 33. By exposing and developing the photoresist film 33, for example, five openings 33A are formed in the bottom surface of the recess 20. Two openings 33A appear in the cross section shown in FIG. 2E. The diameter of each opening 33A is, for example, 50 μm.

  As shown in FIG. 2F, by etching the substrate 10 using the photoresist film 33 as an etching mask, the through hole 21 reaching the first surface 10A and penetrating the substrate 10 is formed. This etching condition is the same as the etching condition for forming the recess 20. The first conductive film 18 is exposed on the bottom surface of the through hole 21. After the through hole 21 is formed, the photoresist film 33 is removed and the substrate is cleaned.

  As shown in FIG. 2G, insulating films 25 are formed on the second surface 10B of the substrate 10, the side surfaces and bottom surfaces of the recesses 20, and the side surfaces and bottom surfaces of the through holes 21. For example, silicon oxide or the like is used for the insulating film 25. For example, chemical vapor deposition (CVD) can be applied to the formation of the insulating film 25. The insulating film 25 deposited on the bottom surface of the through hole 21, that is, the surface of the first conductive film 18, is thinner than the insulating film 25 deposited on the bottom surface of the recess 20 and the second surface 10B.

As shown in FIG. 2H, the insulating film 25 deposited on the bottom surface of the through hole 21, that is, on the first conductive film 18, is removed by anisotropic etching. For this anisotropic etching, for example, RIE using C ₄ F ₈ as an etching gas is applied. By this etching, the first conductive film 18 is exposed on the bottom surface of the through hole 21.

  Since the insulating film 25 deposited on the second surface 10B and the bottom surface of the recess 20 is thicker than the insulating film 25 deposited on the bottom surface of the through hole 21, the bottom surface of the second surface 10B and the recess 20 The insulating film 25 remains. Further, since anisotropic etching is used, the insulating film 25 remains on the side surfaces of the recesses 20 and the side surfaces of the through holes 21.

  As shown in FIG. 2I, a liner (not shown) made of Ti and a seed layer 26 made of Cu are formed on the insulating film 25 and on the first conductive film 18 exposed at the bottom surface of the through hole 21. Form. The thickness of the liner is 20 nm, for example, and the thickness of the seed layer 26 is 100 nm, for example. For example, sputtering is applied to form the liner and seed layer 26.

  A photoresist film 35 is formed on the seed layer 26. For example, a spray coating method can be applied to the formation of the photoresist film 35. An opening 35A is formed by exposing and developing the photoresist film 35. The opening 35A matches the planar shape of the plating film 27 (FIG. 1A) to be formed.

  As shown in FIG. 2J, a plating film 27 is formed by electroplating copper on the seed layer 26 in the opening 35A using the seed layer 26 as an electrode. The thickness of the plating film 27 is, for example, 20 μm. The through hole 21 having a diameter of about 50 μm is completely filled with the plating film 27. Since the diameter of the recess 20 is 200 μm, the recess 20 is not completely filled with the plating film 27. For this reason, a depression reflecting the shape of the side surface and the bottom surface of the recess 20 appears on the surface of the plating film 27.

  As shown in FIG. 2K, the photoresist film 35 (FIG. 2J) is removed. The seed layer 26 is exposed in a region where the plating film 27 is not formed. After removing the photoresist film 35, the substrate 10 is separated from the glass handle wafer 30.

  As shown in FIG. 2L, the seed layer 26 (FIG. 2K) in the region where the plating film 27 is not formed is removed. A second conductive film 28 composed of two layers of a seed layer 26 and a plating film 27 is formed. The insulating film 25 is exposed in a region where the second conductive film 28 is not formed.

  As shown in FIG. 2M, a protective film 30 is formed on the insulating film 25 and the second conductive film 28. The protective film 30 is formed by CVD using, for example, tetraethoxysilane (TEOS). The thickness of the protective film 30 is 2 μm, for example. As shown in FIG. 1, an opening is formed in the protective film 30. A land 28A, which is a part of the second conductive film 28, is exposed at the bottom of the opening. A bump 41 is formed on the land 28A.

  In the method according to the above embodiment, the depth of the through hole 21 is equal to the thickness (about 50 μm) of the substrate 10 remaining at the position where the recess 20 is formed. For this reason, the aspect ratio of the through-hole 21 is smaller than that of the through-hole 21 that reaches the first surface 10A from the second surface 10B of the substrate 10 and has the same diameter as the through-hole 21. Thereby, the inside of the through hole 21 can be easily embedded with a metal such as copper.

  In order to reduce the aspect ratio of the through hole, the through hole having a uniform thickness from the second surface 10B to the first surface 10A may be thickened. However, when the through hole is thickened, the laminated film 14 is easily deformed due to the stress applied to the laminated film 14 in contact with the metal in the through hole due to the difference in thermal expansion coefficient between the metal in the through hole and the substrate 10. Become. In the embodiment, since the through-hole 21 in the portion in contact with the laminated film 14 is made thinner than the recess 20, the stress applied to the laminated film 14 can be reduced and deformation of the laminated film 14 can be reduced.

  Furthermore, since the recess 20 is not completely filled with the second conductive film 28, the amount of the metal material used can be reduced as compared with the case where the recess 20 is filled with the conductive film.

  Next, the evaluation result of the effect of reducing the deformation of the laminated film will be described. 3A to 3G are cross-sectional views of the through electrode portion of the sample to be evaluated. In any sample, the thickness of the substrate (corresponding to the substrate 10 in FIG. 1A) is 200 μm, the thickness of the laminated film (corresponding to the laminated film 14 in FIG. 1A) is 10 μm, and the first conductive film (the first conductive film in FIG. 1A). The thickness of the second conductive film (corresponding to the second conductive film 28 in FIG. 1A) covering the second surface 10B was 10 μm. The substrate material was Si, and the first and second conductive films were Cu. The thermal expansion coefficients of Si and Cu were 2.3 ppm and 16 ppm, respectively. The laminated film usually has a laminated structure of a low dielectric constant insulating material and copper wiring. For this reason, as the thermal expansion coefficient of the laminated film, an intermediate value between the thermal expansion coefficients of both is adopted and set to 8 ppm.

  In the sample A shown in FIG. 3A, a through hole having a diameter of 50 μm penetrates from one surface of the substrate to the other surface. The through hole is completely filled with the second conductive film. The diameter of the first conductive film was 60 μm.

  In the sample B shown in FIG. 3B, the through hole having a diameter of 50 μm is not filled with the second conductive film, and the second conductive film is formed only on the side surface. The thickness of the second conductive film on the side surface was 5 μm. The diameter of the first conductive film is the same as the sample in FIG. 3A.

  In the sample C shown in FIG. 3C, a recess (corresponding to the recess 20 in FIG. 1A) and a through hole (corresponding to the through hole 21 in FIG. 1A) thinner than the recess are formed. The diameter of the recess was 50 μm and the depth was 150 μm. The diameter of the through hole was 10 μm. The recess and the through hole are completely filled with the second conductive film. The diameter of the first conductive film is the same as the sample in FIG. 3A.

  In the sample D shown in FIG. 3D, a through hole having a diameter of 200 μm penetrates from one surface of the substrate to the other surface. The through hole is completely filled with the second conductive film. The first conductive film matches the planar shape of the through hole.

  In samples E to G shown in FIGS. 3E to 3G, a recess (corresponding to the recess 20 in FIG. 1A) and a through hole (corresponding to the through hole 21 in FIG. 1A) thinner than the recess are formed. The diameter of the recess was 200 μm and the depth was 150 μm. The thickness of the 2nd electrically conductive film formed in the side surface and bottom face of a recessed part was 10 micrometers.

  In the samples E and F shown in FIGS. 3E and 3F, one through hole is formed, and in the sample G shown in FIG. 3G, 21 through holes are formed. FIG. 3Ga shows a cross-sectional view taken along one-dot chain line 3Ga-3Ga in FIG. 3G. Twenty-one through holes are distributed almost uniformly on the bottom surface of the recess. The diameter of the through hole of sample E shown in FIG. 3E is 50 μm, and the diameter of the through hole of samples F and G shown in FIGS. 3F and 3G is 20 μm. The diameter of the first conductive film of samples E and F shown in FIGS. 3E and 3F is 60 μm, and the diameter of the first conductive film of sample G shown in FIG. 3G is 200 μm.

  Since it is considered that copper is recrystallized at a temperature of about 250 ° C., it was assumed that the stress of the substrate, the laminated film, and the first and second conductive films was 0 when the temperature was 250 ° C. The deformation amount at temperatures of 25 ° C., 200 ° C., and 500 ° C. was calculated by simulation.

  As shown in FIG. 4A, the effect of reducing the deformation amount was evaluated by calculating the lifting amount Ph of the surface of the laminated film.

  FIG. 4B shows calculation results of the lifting amount Ph of the samples A to G shown in FIGS. 3A to 3G. The horizontal axis represents temperature in the unit “° C.”, and the vertical axis represents the lifting amount Ph in the unit “μm”. The negative lifting amount Ph means that a depression is generated in the laminated film. Reference signs A to G attached to the broken lines in FIG. 4B correspond to the samples A to G shown in FIGS. 3A to 3G, respectively. In Sample D, since the through electrode in contact with the laminated film is thick, a large deformation occurs compared to other samples.

  When comparing the sample A and the sample E having the same thickness of the through electrode in the portion in contact with the laminated film, it can be seen that the magnitude of the deformation amount of both is substantially equal. However, the aspect ratio of the through hole of sample A is larger than the aspect ratio of the through hole of sample E. If the aspect ratio of the through hole to be formed becomes large, the process of forming the through hole becomes difficult. Furthermore, the process of filling the through hole with a metal material becomes difficult. By forming the recess as in the sample E, the aspect ratio of the through hole can be made smaller than that in the sample A, and the deformation amount generated in the laminated film can be suppressed to the same level.

  The deformation amount of the laminated film of Samples C, F, and G is small compared to other samples. This is because the portion of the through electrode in contact with the laminated film is thin. The concave portions of the samples F and G are larger than the concave portion of the sample C. However, in the samples F and G, the concave portions are not filled with the second conductive film. For this reason, the influence which the volume contraction of the 2nd electrically conductive film in a recessed part has on a laminated film is small. As described above, even if the concave portion is enlarged, an increase in the amount of deformation generated in the laminated film can be suppressed by leaving the cavity without filling the concave portion with the second conductive film.

  Further, when comparing samples F and G, it can be seen that the amount of deformation of the laminated film does not increase even if the number of through holes is increased. Increasing the number of through holes is preferable in terms of reducing electric resistance. In addition, even if a filling failure occurs in one through hole, electrical connection is ensured in the other through hole. Therefore, it is preferable to arrange a plurality of through holes from the viewpoint of yield.

  In FIG. 1A, if the second conductive film 28 deposited on the side surface of the recess 20 becomes too thin, the electrical resistance increases. The area of the flat cross section of the second conductive film 28 deposited on the side surface of the recess 20 is preferably equal to or larger than the total area of the flat cross sections of the through holes 21. When this configuration is adopted, the current density of the current flowing in the depth direction through the second conductive film 28 deposited on the side surface of the recess 20 is the current density of the current flowing through the second conductive film 28 in the through hole 21. Is prevented from becoming higher.

  Next, a preferable range of the thickness of the second conductive film 28 will be described. In order to completely fill the through hole 21 with the second conductive film 28, it is preferable that the thickness of the second conductive film 28 is set to be 1/2 or more of the diameter of the through hole 21. If the second conductive film 28 becomes too thick, the recess 20 is completely filled with the second conductive film 28. In order to prevent the recess 20 from being filled up, the second conductive film 28 is preferably thinner than the depth of the recess 20.

  Next, a preferable range of the depth of the recess 20 will be described. When the recess 20 is deepened, a part of the substrate 10 remaining in the region where the recess 20 is formed becomes thinner. If the remaining portion of the substrate 10 becomes too thin, the stress of the second conductive film 20 acts on the thinned portion of the substrate 10 to easily cause deformation. In addition, when the diameter of the recess 20 is increased, the thinned portion of the substrate 10 is also increased and is easily deformed. In order to prevent deformation of the thinned portion of the substrate 10, it is preferable that the thickness of the thinned portion is set to 1/10 or more of the diameter of the recess 20.

  When the planar shape of the recess 20 is not circular, the “diameter of the recess 20” may be read as the diameter of the largest circle included in the planar figure of the recess 20.

  In the above embodiment, copper or a copper alloy is used for the second conductive film 28, but other metals may be used. Further, although silicon is used for the substrate 10, a compound semiconductor may be used.

FIG. 5 shows a cross-sectional view of a through electrode substrate according to a modification of the above embodiment. In FIG. 5, the same reference numerals as those assigned to the corresponding components shown in FIG. 1A are attached to the components of the through electrode substrate. In the above embodiment, as shown in FIG. 1A, the side surface of the recess 20 is substantially perpendicular to the second surface 10B. In the modification shown in FIG. 5, the side surface of the recess 20 is tapered so that the recess 20 becomes thinner as it becomes deeper from the second surface. A taper shape can be formed by using, for example, only SF ₆ as an etching gas for forming the recess 20.

  By making the side surface of the recess 20 into a tapered shape, it is possible to easily fill the second conductive film 28 into the through hole 21.

  FIG. 6 is a sectional view of a through electrode substrate according to another modification of the above embodiment. In the above embodiment, the through electrode is formed on the semiconductor substrate on which the transistor and the like are formed. However, in the modification shown in FIG. 6, the through electrode is formed in the interposer.

  For the interposer, for example, a substrate 50 made of an insulating resin is used. A laminated film 51 including rewiring is formed on the first surface 50 </ b> A of the substrate 50. The stacked film 51 includes a first conductive film 52 that is in contact with the first surface 50A. A land 53 and a protective film 54 are formed on the laminated film 51. The protective film 54 is formed with an opening for exposing the land 53. Bumps 55 are formed on the lands 53 exposed in the openings.

  The land 53 is connected to the first conductive film 52 by wiring in the laminated film 51. A decoupling capacitor or the like may be disposed in the laminated film 51.

  A recess 60 is formed in the substrate 50 from the second surface 50B to the inside. A through hole 61 extending from the bottom surface of the recess 60 to the first surface 50A is formed. A second conductive film 65 covers the side and bottom surfaces of the recess 60 and fills the through hole 61. The second conductive film 65 is electrically connected to the first conductive film 52.

  The second conductive film 65 extends from the edge of the opening of the recess 60 to a partial region of the second surface 50B, and constitutes a land 65A. A protective film 66 covers the second surface 50 </ b> B and the second conductive film 65. In the protective film 65, an opening exposing the land 65A is formed. Bumps 67 are formed on the lands 65A in the openings.

  Also in the modified example shown in FIG. 6, the deformation of the laminated film 51 can be suppressed as in the embodiment shown in FIG. 1A. Furthermore, since the aspect ratio of the through hole 61 is reduced, the inside of the through hole 61 can be easily filled with the second conductive film 65.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited thereto. It will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

10 substrate 10A first surface 10B second surface 11 element isolation insulating film 13 transistor 14 laminated film 15 electrode pad 16 protective film 18 first conductive film (land)
20 Recess 21 Through hole 25 Insulating film 26 Seed layer 27 Plating film 28 Second conductive film 28A Land 30 Glass handle wafer 31 Photoresist film 31A Opening 33 Photoresist film 33A Opening 35 Photoresist film 35A Opening 40 Protective film 41 Bump 50 Substrate 50A First surface 50B Second surface 51 Multilayer film 52 First conductive film 53 Land 54 Protective film 55 Bump 60 Recess 61 Through hole 65 Second conductive film 65A Land 66 Protective film 67 Bump

Claims (5)

A substrate,
A laminated film formed on the first surface of the substrate and including a first conductive film;
A concave portion that is formed from the second surface opposite to the first surface of the substrate toward the inside, and does not reach the first surface;
A through hole that reaches from the bottom surface of the recess to the first surface, and is thinner than the recess;
A through electrode substrate having a second conductive film embedded in the through hole and connected to the first conductive film, covering a side surface and a bottom surface of the concave portion, but not completely filling the concave portion.   2. The through electrode substrate according to claim 1, wherein a part of the surface of the second conductive film has a shape reflecting a bottom surface and a side surface of the recess.   3. The penetration according to claim 1, further comprising at least one other through hole that reaches from the bottom surface of the recess to the first surface, is narrower than the recess, and is filled with the second conductive film. Electrode substrate.   The thickness from the bottom face of the said recessed part to the said 1st surface is 1/10 or more of the diameter of the largest circle | round | yen enclosed in the plane figure of the said recessed part. Through electrode substrate.   5. The through electrode substrate according to claim 1, wherein a side surface of the recess has a tapered shape that becomes narrower from the second surface toward the first surface. 6.

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