JP2015142106A - Semiconductor device and manufacturing method of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device and a manufacturing method of semiconductor device capable of improving the reliability in continuity characteristics of through electrodes.SOLUTION: A semiconductor device according to an embodiment includes a through-hole and a metal part. The through-hole penetrates a base plate across the surface and the rear face thereof. The metal part is formed in the through-hole with a material which contains at least one kind of metal selected from Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B or Hf including a cavity therein.

Description

  Embodiments described herein relate generally to a semiconductor device and a method for manufacturing the semiconductor device.

  2. Description of the Related Art Conventionally, there is a technique for reducing the area occupied by a semiconductor device by stacking chips each having a semiconductor element or an integrated circuit formed on a substrate in multiple stages. The chips to be stacked are electrically connected by a through electrode in which a metal is embedded in a through hole that penetrates the substrate.

  The embedding of the metal into the through hole is generally performed by electrolytic plating. Such electrolytic plating includes, for example, bottom-up plating in which metal is gradually deposited from the closed bottom surface of the through hole toward the opening, and conformal plating in which metal is deposited from the entire inner peripheral surface of the through hole.

  Conformal plating has an advantage that metal can be embedded in the through hole in a shorter time than bottom-up plating. In such conformal plating, since the electric field concentrates at the opening end of the through hole, the deposition rate of the metal is faster at the opening end than at the inner peripheral surface of the through hole. Therefore, a cavity may be generated inside the metal embedded in the through hole.

  The cavity generated inside the metal may move inside the metal due to electromigration caused by the current flowing through the metal during conformal plating and cause a shape defect in the metal. Such metal shape defects may reduce the reliability of the through-electrode conduction characteristics.

JP 2012-142414 A US Patent Application Publication No. 2012/0276733

  An object of one embodiment of the present invention is to provide a semiconductor device and a method of manufacturing the semiconductor device that can improve the reliability of the conduction characteristics of the through electrode.

  According to one embodiment of the present invention, a semiconductor device is provided. The semiconductor device includes a through hole and a metal part. The through hole penetrates the front and back of the semiconductor substrate. The metal part has at least one of gold, silver, nickel, cobalt, palladium, tungsten, tantalum, platinum, rhodium, iridium, ruthenium, osmium, rhenium, molybdenum, niobium, boron, and hafnium inside the through hole. It is made of a material containing a metal and encloses a cavity.

FIG. 3 is a cross-sectional view schematically showing the configuration of the semiconductor device according to the embodiment. Sectional drawing which shows the manufacturing process of the semiconductor device which concerns on embodiment. Sectional drawing which shows the manufacturing process of the semiconductor device which concerns on embodiment. Sectional drawing which shows the manufacturing process of the semiconductor device which concerns on embodiment. Sectional drawing which shows typically the structure of the semiconductor device which concerns on the modification of embodiment.

  Exemplary embodiments of a semiconductor device and a method for manufacturing the semiconductor device will be explained below in detail with reference to the accompanying drawings. In addition, this invention is not limited by this embodiment.

  FIG. 1 is a cross-sectional view schematically showing a configuration of a semiconductor device 1 according to the embodiment. In the following, for convenience, the upper surface of the substrate 2 shown in the figure is sometimes referred to as the front surface, and the lower surface is sometimes referred to as the back surface. As shown in FIG. 1, the semiconductor device 1 includes a through electrode that penetrates the front and back of a substrate 2 formed of a semiconductor such as Si (silicon). The surface of the substrate 2 is covered with an insulating film 6, and the back surface of the substrate 2 is covered with an insulating film 3.

  The through electrode includes a bump 10, an electrode pad 4, a seed film 7, and a metal part 8. The bumps 10 are formed by solder, for example, and are provided on the surface side of the substrate 2. The electrode pad 4 is formed of, for example, silicide and is provided at a position facing the bump 10 with the substrate 2 interposed therebetween.

  The seed film 7 is made of, for example, Cu (copper). The seed film 7 is formed around the opening of the through hole 5 on the surface of the insulating film 6, the surface of the electrode pad 4, and the surface of the substrate 2 that covers the inner peripheral surface of the through hole 5 penetrating the front and back of the substrate 2. It is provided on the surface of the insulating film 6 to be covered.

  The metal part 8 is formed by depositing metal on the surface of the seed film 7 by conformal plating. Thereby, the metal part 8 is formed on the hole core side of the through hole 5 with respect to the seed film 7. In conformal plating, metal is gradually deposited from the entire surface of the seed film 7.

  Therefore, in the semiconductor device 1, as shown in FIG. 1, the dimension in the depth direction of the through-hole 5 is formed larger than the dimension in the direction orthogonal to the depth direction. Thereby, in the semiconductor device 1, when the metal portion 8 is formed by conformal plating, the opening on the surface side of the substrate 2 in the through hole 5 is reliably closed by the metal portion 8.

  In addition, the metal part 8 includes a cavity 9 on the hole core side of the through hole 5. As described above, since the semiconductor device 1 includes the cavity 9 inside the metal portion 8, for example, when the heat treatment for processing the shape of the bump 10 into a hemisphere is performed, damage to the substrate 2 can be suppressed.

  Specifically, in the process of performing heat treatment, the metal part 8 may cause thermal expansion. In such a case, the cavity 9 inside the metal part 8 absorbs the thermal expansion force exerted by the metal part 8 to the outside, and reduces the force applied from the metal part 8 to the substrate 2, thereby suppressing the breakage of the substrate 2. Can do.

  The metal portion 8 is made of a metal other than Cu, for example, Ni (nickel), Au (gold), Ag (silver), Co (cobalt), Pd (palladium), W (tungsten), Ta (tantalum), platinum. (Pt), rhodium (Rh), iridium (Ir), ruthenium (Ru), osmium (Os), rhenium (Re), molybdenum (Mo), niobium (Nb), boron (B), hafnium (Hf) , Formed of a material containing at least one metal. Thereby, the semiconductor device 1 can suppress occurrence of a shape defect in the metal part 8 in a process in which conformal plating is performed.

  Specifically, in the process of performing conformal plating, a relatively high voltage may be applied to the metal part 8 in some cases. In such a case, when the metal portion 8 is formed using general Cu as the material of the through electrode, Cu is a metal having a relatively low resistance to electromigration, and thus a shape defect may occur.

  Therefore, in the semiconductor device 1, the metal part 8 has higher resistance to electromigration than Cu, Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb. , B, and Hf are formed of a material containing at least one kind of metal.

  Thereby, the semiconductor device 1 can suppress occurrence of a shape defect in the metal part 8 in a process in which conformal plating is performed. Therefore, according to the semiconductor device 1, the conduction characteristics of the through electrode can be improved.

  Next, a method for manufacturing the semiconductor device 1 according to the embodiment will be described with reference to FIGS. 2-4 is sectional drawing which shows the manufacturing process of the semiconductor device 1 which concerns on embodiment. Here, a manufacturing process for forming through electrode portions penetrating the front and back of the substrate 2 included in the semiconductor device 1 will be described.

  When forming the through electrode portion of the semiconductor device 1, as shown in FIG. 2A, first, an insulating film 3 such as a Si oxide film is formed on the back surface of the substrate 2 by, for example, CVD (Chemical Vapor Deposition). To do. Then, electrode pads 4 are formed on the back surface side of the substrate 2 by patterning, for example, silicide at a predetermined position on the back surface side of the insulating film 3.

  Subsequently, by performing RIE (Reactive Ion Etching) on the position facing the electrode pad 4 on the surface of the substrate 2, as shown in FIG. 2B, the through holes 5 penetrating the front and back of the substrate 2 are formed. Then, the surface of the electrode pad 4 is exposed.

  At this time, the through hole is formed such that the dimension in the depth direction is larger than the dimension in the direction orthogonal to the depth direction. Thereby, when the metal part 8 is formed later by conformal plating, the opening on the surface of the substrate 2 in the through hole 5 can be reliably closed by the metal part 8.

  Subsequently, as shown in FIG. 2C, an insulating film 6 such as a Si oxide film is formed on the exposed surface of the electrode pad 4, the inner peripheral surface of the through hole 5, and the surface of the substrate 2 by, for example, CVD. Form. Thereafter, as shown in FIG. 3A, the surface of the electrode pad 4 is exposed again by selectively removing the insulating film 6 formed on the surface of the electrode pad 4 by etching.

  Subsequently, as shown in FIG. 3B, the exposed surface of the electrode pad 4, the surface of the insulating film 6 covering the inner peripheral surface of the through hole 5, and the insulating film 6 covering the surface of the substrate 2 are formed. For example, a Cu film is formed on the surface, thereby forming a seed film 7 for the next plating. The seed film 7 is formed by, for example, vacuum deposition or sputtering.

  Thereafter, as shown in FIG. 3C, a resist 21 such as a resin is formed on the surface of the seed film 7 covering the surface side of the substrate 2. Then, by patterning the resist 21, an opening is formed at a position facing the electrode pad 4 in the resist 21. At this time, the opening is formed so that the cross-sectional dimension orthogonal to the thickness direction of the substrate 2 is substantially equal to the corresponding cross-sectional dimension of the electrode pad 4.

  Subsequently, as shown in FIG. 4A, for example, Ni conformal plating is performed on the surface of the seed film 7 not covered with the resist 21. Thereby, the formation of the metal portion 8 is started by conformal plating inside the through hole 5 in which the other opening on the back surface side of the substrate 2 is closed by the seed film 7.

  Here, the metal part 8 is formed by conformal plating of Ni on the surface of the seed film 7, but the material of the metal part 8 is not limited to Ni, and is more resistant to electromigration than Cu. Other metals having high resistance may be used.

  The material of the metal portion 8 is, for example, any one of Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B, and Hf, Alternatively, even an alloy containing at least one kind of metal among Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B, and Hf. Good.

  At the beginning of the formation of the metal part 8, the inside of the through hole 5 covered with the metal part 8 is in a state where the surface of the substrate 2 is opened. If the opening on the surface side of the substrate 2 is not closed, the semiconductor device 1 may be damaged during the subsequent heat treatment. Therefore, thereafter, Ni conformal plating is continued, and one opening on the surface side of the substrate 2 in the through hole 5 is closed by the metal portion 8 as shown in FIG. As a result, a cavity 9 is formed in the center of the metal portion 8.

  Thereafter, as shown in FIG. 4C, bumps 10 are formed on the surface of the metal part 8 surrounded by the resist 21, for example, by laminating a solder layer. Finally, the seed film 7 directly under the resist 21 is removed together with the resist 21, and heat treatment is performed to process the bump 10 into a hemispherical shape, thereby completing the semiconductor device 1 shown in FIG.

  As described above, the semiconductor device 1 according to the embodiment includes the through hole 5 that penetrates the front and back of the substrate 2, and the metal portion 8 that is formed in the through hole 5 by conformal plating and encloses the cavity 9. . According to the semiconductor device 1, when heat treatment is performed in the manufacturing process, the thermal expansion force of the metal portion 8 can be reduced by the cavity 9 included in the metal portion 8. Damage to the substrate 2 can be suppressed.

  The metal portion 8 of the semiconductor device 1 according to the embodiment includes Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B, and Hf. , Including at least one metal. These Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B, and Hf are metals that have higher resistance to electromigration than Cu.

  Therefore, according to the semiconductor device 1, when the metal part 8 is formed by conformal plating, by suppressing the occurrence of a shape defect of the metal part 8 due to electromigration due to the voltage applied to the metal part 8, the through electrode The conduction characteristics can be improved.

  The above-described embodiment is an example, and various modifications are possible. FIG. 5 is a cross-sectional view schematically showing a configuration of a semiconductor device 1a according to a modification of the embodiment. Hereinafter, the same components as those illustrated in FIG. 1 are denoted by the same reference numerals as those illustrated in FIG.

  As shown in FIG. 5, the semiconductor device 1a has the same configuration as that of the semiconductor device 1 shown in FIG. 1 except that it includes a Cu layer 7a covering the outer peripheral surface of the metal portion 8a on the through hole 5 side. The Cu layer 7a is formed by conformal plating of Cu on the surface of the seed film 7 shown in FIG.

  The metal part 8a has at least one of Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B, and Hf on the surface of the Cu layer 7a. Formed by conformal plating of materials containing different types of metals. Thereby, the metal part 8a is formed in the hole core side of the through-hole 5 rather than Cu layer 7a. Similar to the metal layer 8 shown in FIG. 1, the metal portion 8a also includes a cavity 9 therein.

  Therefore, according to the semiconductor device 1a, when the heat treatment is performed in the manufacturing process, the thermal expansion force of the metal portion 8a can be reduced by the cavity 9 included in the metal portion 8a. It is possible to suppress the damage of the substrate 2 due to the above.

  The cavity 9 in the semiconductor device 1a is included in a metal having higher resistance to electromigration than Cu. Therefore, according to the semiconductor device 1a, when the metal portion 8a is formed by conformal plating, the conduction characteristics of the through electrode can be improved by suppressing the occurrence of a shape defect of the metal portion 8a due to electromigration. .

  Further, according to the semiconductor device 1a, Ni, Au, Ag, Co, Pd, W, Ta, Pt, Rh, Ir, Ru, Os, Re, Mo, Nb, B, and Hf used for forming the metal portion 8a are used. Since the amount of expensive metal compared to Cu can be reduced, the manufacturing cost can be reduced.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  1, 1a Semiconductor device, 2 substrate, 3, 6 insulating film, 4 electrode pad, 5 through-hole, 7 seed film, 7a Cu layer, 8, 8a metal part, 9 cavity, 10 bump

Claims (5)

A through hole penetrating the front and back of the semiconductor substrate;
The inside of the through hole contains at least one metal selected from gold, silver, nickel, cobalt, palladium, tungsten, tantalum, platinum, rhodium, iridium, ruthenium, osmium, rhenium, molybdenum, niobium, boron, and hafnium. A semiconductor device comprising: a metal portion formed of a material and enclosing a cavity. The semiconductor device according to claim 1, further comprising: a copper layer that covers an outer peripheral surface of the metal portion on the through hole side. The through hole is
The semiconductor device according to claim 1, wherein a dimension in a depth direction is larger than a dimension in a direction perpendicular to the depth direction. A through hole penetrating the front and back of the semiconductor substrate;
A copper layer formed inside the through hole;
A semiconductor device, comprising: a metal portion formed of a metal other than copper and enclosing a cavity, on a hole core side of the through hole with respect to the copper layer. Forming a through hole penetrating the front and back of the semiconductor substrate;
The inside of the through hole contains at least one kind of metal of gold, silver, nickel, cobalt, palladium, tungsten, tantalum, platinum, rhodium, iridium, ruthenium, osmium, rhenium, molybdenum, niobium, boron, hafnium, Forming a metal part that encloses the cavity. A method of manufacturing a semiconductor device, comprising:

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