Semiconductor substrate

Abstract

The invention relates to a semiconductor substrate. This semiconductor substrate is provided with: a base material; a non-magnetic metal member that contains a non-magnetic material; a conductive film that is formed on the metal member and is formed of the same material as the non-magnetic material contained in the metal member; and a bonding part that bonds the base material to the side of the metal member on which the conductive film is formed and is formed of a non-magnetic material.

Description

Technical Field

[0001] The present invention relates to a semiconductor substrate. Background Art

[0002] Conventionally, there is known a semiconductor substrate in which a metal member is bonded to a base material (for example, Patent Documents 1 and 2).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6629317

[0006] Patent Document 2: Japanese Patent No. 6883513 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] However, according to the conventional techniques such as Patent Documents 1 and 2, there is still room for improvement in the technique of improving the adhesion between the base material and the metal member in the semiconductor substrate.

[0009] An object of the present invention is to provide a technology for improving the adhesion between a base material and a metal member in a semiconductor substrate.

[0010] Solutions for solving problems

[0011] The present invention has been made to solve at least a part of the above-mentioned problems, and can be implemented as the following aspects.

[0012] (1) According to one embodiment of the present invention, a semiconductor substrate is provided. The semiconductor substrate comprises: a substrate; a metal member comprising a non-magnetic material and having non-magnetic properties; a conductive film formed on the metal member, the conductive film comprising the same material as the non-magnetic material contained in the metal member; and a joint portion that joins a side of the metal member on which the conductive film is formed to the substrate, the joint portion being formed of a non-magnetic material.

[0013] According to this structure, the conductive film formed on the metal member includes the same material as the non-magnetic material contained in the metal member. As a result, the adhesion between the metal member and the conductive film is improved, and thus the adhesion between the substrate and the metal member via the conductive film and the joint portion can be improved.

[0014] (2) In the semiconductor substrate of the above-mentioned method, the substrate may include: an insulating member formed of a non-magnetic material; and a non-magnetic film formed on the insulating member. According to this structure, the substrate includes an insulating member formed of a non-magnetic material and a non-magnetic film formed on the insulating member, and thus the substrate has non-magnetic properties. Thus, the non-magnetic substrate and the non-magnetic metal member are joined by a joint formed of a non-magnetic material, thereby making the semiconductor substrate non-magnetic. Therefore, the semiconductor substrate as a whole is not easily affected by a magnetic field, and therefore can be applied to fields requiring non-magnetic properties.

[0015] (3) The semiconductor substrate of the above aspect may further include a barrier film formed between the conductive film and the junction. According to this structure, the barrier film formed between the conductive film and the junction can suppress diffusion of a material contained in the junction into the conductive film.

[0016] (4) In the semiconductor substrate of the above-mentioned embodiment, the metal component may be formed of an alloy of tungsten and copper, and the conductive film may be formed of copper. According to this structure, the conductive film is formed of copper, which is a non-magnetic material forming the metal component. As a result, the conductive film is difficult to peel off from the metal component, and thus the adhesion between the metal component and the conductive film is improved. Therefore, the adhesion between the substrate and the metal component via the conductive film and the joint portion can be improved.

[0017] The present invention can be implemented in various forms, for example, in the form of a semiconductor package including a semiconductor substrate, a method for manufacturing a semiconductor substrate, a computer program for executing the manufacturing of a semiconductor substrate, and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a cross-sectional view of the semiconductor substrate according to the first embodiment.

[0019] Figure 2 FIG. 1 is a first diagram for explaining the method for manufacturing a semiconductor substrate according to the first embodiment.

[0020] Figure 3 FIG. 2 is a second diagram for explaining the method for manufacturing the semiconductor substrate according to the first embodiment.

[0021] Figure 4 FIG. 3 is a diagram for explaining the method for manufacturing the semiconductor substrate according to the first embodiment.

[0022] Figure 5 FIG. 4 is a diagram for explaining the method for manufacturing the semiconductor substrate according to the first embodiment.

[0023] Description of Reference Numerals

[0024] 1. semiconductor substrate; 10. base material; 11. insulating member; 12. non-magnetic film; 20. metal member; 30. conductive film; 40. barrier film; 50. joint portion. DETAILED DESCRIPTION

[0025] <First Embodiment>

[0026] Figure 1 1 is a cross-sectional view of a semiconductor substrate of the first embodiment. The semiconductor substrate 1 of the present embodiment is a substrate on which a semiconductor is mounted and has a heat sink for dissipating heat generated by the semiconductor to the outside. The semiconductor substrate 1 of the present embodiment is mainly used in quantum computers and other situations where non-magnetic properties are required in a superconducting environment. The semiconductor substrate 1 includes a base material 10, a metal member 20, a conductive film 30, a barrier film 40, and a bonding portion 50. In addition, for the sake of convenience, Figures 1 to 5 The relationship between the thicknesses of the substrate 10 , the metal member 20 , the conductive film 30 , the barrier film 40 , and the bonding portion 50 in the figure is different from the actual relationship between the thicknesses.

[0027] The substrate 10 includes an insulating member 11 formed of a non-magnetic material and a non-magnetic film 12 formed on the insulating member 11. The substrate 10 supports a metal member 20 described later and a semiconductor not shown.

[0028] The insulating member 11 is a member having a flat plate shape and is made of a non-magnetic material having insulating properties, such as aluminum nitride (AlN), and has insulating properties. Here, "having insulating properties" means that the insulation resistance value is 1.0×10 8 Ω or more. In addition, the shape of the insulating member 11 is not limited thereto, as long as it is a shape that can support the metal member 20 and the semiconductor. In addition, the non-magnetic material forming the insulating member 11 is not limited to aluminum nitride. It can also be an oxide-based ceramic such as aluminum oxide (Al2O3), silicon dioxide (SiO2), titanium dioxide (TiO2), zirconium oxide (ZrO2), a nitride-based ceramic such as silicon nitride (SiN), titanium nitride (TiN), etc.

[0029] The non-magnetic film 12 is formed on the surface 11a of the insulating member 11. The non-magnetic film 12 includes a titanium film 121 formed of titanium (Ti), a copper film 122 formed of copper (Cu), a platinum film 123 formed of platinum (Pt), and a gold film 124 formed of gold (Au). In the non-magnetic film 12 of the present embodiment, the titanium film 121, the copper film 122, the platinum film 123, and the gold film 124 are stacked in this order from the surface 11a side of the insulating member 11.

[0030] The substrate 10 has an insulating member 11 formed of a non-magnetic material and a non-magnetic film 12 formed of a metal of a non-magnetic material, and has non-magnetic properties. Here, "having non-magnetism" means that it has almost no magnetism and may also contain a small amount of magnetic material. In the present embodiment, the "member having non-magnetism" is equivalent to a member in which the average amount of the sum of the amount of magnetic elements such as iron (Fe), nickel (Ni), cobalt (Co), and neodymium (Nd) contained in each of the plurality of measurement target areas set in the member is divided by the number of measurement target areas and is less than a specific value. Specifically, using a scanning electron microscope (SEM) and an energy dispersive X-ray analyzer (EDS), under specified measurement conditions (magnification: 5000 times, acceleration voltage of the electron gun: 20kV, distance from the electron gun to the measurement target area: 10mm), elemental analysis is performed on at least 10 measurement target areas set on the surface or cross section of the member. In the present embodiment, the member whose result of such elemental analysis, i.e., the average detected amount of the magnetic element is less than 1.0wt% is regarded as a "member having non-magnetism". The substrate 10 is a “non-magnetic member” in which the average detected amount of an element exhibiting magnetism is 1.0 wt % or less.

[0031] The metal member 20 is a member including a non-magnetic material and having non-magnetic properties. In the present embodiment, the metal member 20 is a heat sink formed of an alloy of tungsten (W) and copper. The metal member 20 has a function of releasing heat generated by a semiconductor mounted on the semiconductor substrate 1 to the outside.

[0032] The conductive film 30 is formed on the metal member 20. The conductive film 30 includes the same material as the non-magnetic material included in the metal member 20. In the present embodiment, the conductive film 30 is formed of copper among tungsten and copper included in the metal member 20. Figure 1 As shown, the conductive film 30 is formed to cover the entire metal member 20. In addition, the position where the conductive film 30 is formed in the metal member 20 is not limited thereto. The conductive film 30 may be formed only on the side bonded to the substrate 10 by the bonding portion 50.

[0033] The barrier film 40 is formed between the conductive film 30 and the bonding portion 50 described later. In this embodiment, the barrier film 40 is formed of platinum and is formed to cover the outside of the conductive film 30. The barrier film 40 suppresses diffusion of gold atoms and tin atoms contained in the bonding portion 50.

[0034] The gold film 45 is formed so as to cover the outer side of the barrier film 40. The gold film 45 is formed of gold and assists the joining of the metal member 20 and the joining portion 50 via the barrier film 40.

[0035] The joint portion 50 joins the side of the metal member 20 on which the conductive film 30 is formed to the substrate 10. The joint portion 50 is formed of a non-magnetic material. In the present embodiment, the joint portion 50 is a solder formed of gold and tin. The joint portion 50 joins the substrate 10 to the metal member 20. In addition, the non-magnetic material forming the joint portion 50 may be the same as or different from the non-magnetic material included in the insulating member 11 and the metal member 20.

[0036] Figure 2 FIG. 1 is a diagram for explaining a method for manufacturing a semiconductor substrate 1 according to the present embodiment. Here, the method for manufacturing a semiconductor substrate 1 is explained. In the method for manufacturing a semiconductor substrate 1, first, a metal component 20 is prepared. Next, a conductive film 30 is formed on the prepared metal component 20. Specifically, the metal component 20 is plated with copper, and then the plated metal component 20 is annealed by heating. In the present embodiment, the plating process and the annealing process are repeated twice. For the convenience of explanation, Figure 2 The member in which the conductive film 30 is formed on the metal member 20 shown is referred to as the plated member 1 a .

[0037] Figure 3 2 is a diagram for explaining the method for manufacturing the semiconductor substrate 1 of the present embodiment. After forming the conductive film 30 on the metal component 20, a barrier film 40 and a gold film 45 are formed on the surface of the plated component 1a. In the present embodiment, the barrier film 40 is formed by a sputtering method using platinum, and the gold film 45 is formed by sputtering using gold. In addition, the method for forming the barrier film 40 or the gold film 45 is not limited to sputtering, and can also be formed by plating or evaporation. For the convenience of explanation, the component on which the barrier film 40 and the gold film 45 are formed on the surface of the plated component 1a is referred to as a sputtered component 1b.

[0038] Figure 4 FIG. 3 is a diagram for explaining the method for manufacturing the semiconductor substrate 1 according to the present embodiment. In the method for manufacturing the semiconductor substrate 1, Figure 2 and Figure 3 The manufacturing of the sputtering-finished component 1b described in the above is independent, and a non-magnetic film 12 is formed on the prepared insulating component 11. Specifically, a titanium film 121, a copper film 122, a platinum film 123, and a gold film 124 are formed in order on the surface 11a of the insulating component 11. In the present embodiment, the titanium film 121 is formed by sputtering using titanium, and the copper film 122 is formed by sputtering and plating using copper. The platinum film 123 is formed by evaporation using platinum, and the gold film 124 is formed by evaporation using gold. Thus, the substrate 10 is manufactured. In addition, the method of forming the titanium film 121, the copper film 122, the platinum film 123, or the gold film 124 is not limited to sputtering and evaporation. For example, for a part of the film, it can also be formed by plating treatment.

[0039] Figure 5 FIG. 4 is a diagram for explaining the method for manufacturing the semiconductor substrate 1 of the present embodiment. In the method for manufacturing the semiconductor substrate 1, a gold-tin solder foil 50a is prepared independently of the sputtered component 1b and the substrate 10. The gold-tin solder foil 50a is sandwiched between the gold film 45 of the sputtered component 1b and the gold film 124 of the substrate 10. Figure 5 The sputtered component 1b and the substrate 10 are heated in a reflow furnace in a nitrogen atmosphere or a hydrogen atmosphere in a state where the gold-tin solder foil 50a is sandwiched between the sputtered component 1b and the substrate 10. Thus, the sputtered component 1b and the substrate 10 are joined by the joint 50 to manufacture a semiconductor substrate 1. In addition, the method of joining the sputtered component 1b and the substrate 10 may not be a method of using the gold-tin solder foil 50a, but may be a method of applying a gold-tin solder paste.

[0040] According to the semiconductor substrate 1 of the present embodiment described above, the conductive film 30 formed on the metal member 20 is formed of copper, which is the same material as the non-magnetic material contained in the metal member 20. Thus, the occurrence of expansion and other defects between the metal member 20 and the conductive film 30 is suppressed, thereby improving the adhesion between the metal member 20 and the conductive film 30. Therefore, the adhesion of the substrate 10 and the metal member 20 joined via the conductive film 30 and the joint 50 can be improved.

[0041] In addition, according to the semiconductor substrate 1 of the present embodiment, the base material 10 includes the insulating member 11 formed of aluminum nitride as a non-magnetic material and the non-magnetic film 12 formed on the insulating member 11. As a result, the base material 10 has non-magnetic properties, and therefore, by bonding with the non-magnetic metal member 20, the semiconductor substrate 1 as a whole has non-magnetic properties. Therefore, the semiconductor substrate 1 is not easily affected by a magnetic field, and can be used in fields requiring non-magnetic properties.

[0042] Furthermore, according to the semiconductor substrate 1 of the present embodiment, the barrier film 40 is formed between the conductive film 30 and the bonding portion 50 . This can suppress the diffusion of gold atoms and tin atoms contained in the bonding portion 50 into the conductive film 30 .

[0043] Furthermore, according to the semiconductor substrate 1 of the present embodiment, the metal member 20 is formed of an alloy of tungsten and copper, and the conductive film 30 is formed of copper, which is the same material as the non-magnetic material forming the metal member 20. As a result, the conductive film 30 is difficult to be peeled off from the metal member 20, thereby improving the adhesion between the metal member 20 and the conductive film 30. Therefore, the adhesion between the substrate 10 and the metal member 20 via the conductive film 30 and the bonding portion 50 can be improved.

[0044] Furthermore, according to the method for manufacturing the semiconductor substrate 1 of the present embodiment, when the conductive film 30 is formed on the metal member 20, a plating process using copper and an annealing process of heating the film formed by the plating process are performed multiple times. As a result, the residue of the plating solution remaining in the film formed by the plating process is volatilized, and the growth of copper grains is promoted, so that the adhesion between the metal member 20 and the conductive film 30 can be further improved. Therefore, the adhesion of the substrate 10 and the metal member 20 joined via the conductive film 30 and the joint 50 can be further improved.

[0045] <Variations of this embodiment>

[0046] The present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist of the invention. For example, the following modifications are possible.

[0047] [Modification 1]

[0048] In the above-mentioned embodiment, the substrate 10 includes the insulating member 11 formed of a non-magnetic material and the non-magnetic film 12 formed on the insulating member 11. However, the structure of the substrate 10 is not limited thereto, and may be only the insulating member 11. In addition, in the above-mentioned embodiment, the substrate 10 includes the insulating member 11 and the non-magnetic film 12, for example, Figure 1 As shown, the insulating member 11 is joined to the metal member 20 via the non-magnetic film 12 and the joint 50. However, the manner of joining the insulating member 11 to the metal member 20 is not limited thereto. The insulating member 11 may also be joined to the metal member 20 via the joint 50 on the side of the insulating member 11 where the non-magnetic film 12 is not formed. In addition, the non-magnetic material forming the insulating member 11 is not limited to aluminum nitride, and may not have insulating properties. Moreover, the non-magnetic material forming the insulating member 11 may be the same as or different from the non-magnetic material contained in the metal member 20 and the joint 50.

[0049] [Modification 2]

[0050] In the above-described embodiment, the semiconductor substrate 1 includes the barrier film 40 , but the barrier film may not be provided. By providing the barrier film 40 , it is possible to suppress the diffusion of gold atoms and tin atoms contained in the bonding portion 50 into the conductive film 30 .

[0051] [Variation 3]

[0052] In the above-mentioned embodiment, the metal member 20 is a heat sink formed of an alloy of tungsten and copper. The material forming the metal member and the function of the metal member are not limited thereto. The metal member only needs to be made of a non-magnetic material and have non-magnetic properties.

[0053] [Variation 4]

[0054] In the above-described embodiment, the conductive film 30 formed on the metal member 20 is formed by plating the metal member 20 with copper and performing annealing. However, the method of forming the conductive film 30 is not limited thereto and may be formed by sputtering or vapor deposition.

[0055] The present invention has been described above based on the embodiments and variations, but the embodiments of the above-mentioned modes are for easy understanding of the present invention and do not limit the present invention. The present invention can be changed and improved within the scope of its purport and claims, and its equivalents are included in the present invention. In addition, if its technical features are not described as necessary features in this specification, they can be appropriately deleted.

[0056] <Application Example 1>

[0057] A semiconductor substrate, wherein

[0058] The semiconductor substrate has:

[0059] Base material;

[0060] A metal component, which includes a non-magnetic material and has non-magnetic properties;

[0061] a conductive film formed on the metal member, the conductive film including the same material as the non-magnetic material included in the metal member; and

[0062] A bonding portion bonds the side of the metal member on which the conductive film is formed to the base material, and the bonding portion is formed of a non-magnetic material.

[0063] <Application Example 2>

[0064] The semiconductor substrate according to Application Example 1, wherein:

[0065] The substrate has:

[0066] an insulating member formed of a non-magnetic material; and

[0067] A non-magnetic film is formed on the insulating member.

[0068] <Application Example 3>

[0069] The semiconductor substrate according to Application Example 1 or Application Example 2, wherein:

[0070] The semiconductor substrate further includes a barrier film formed between the conductive film and the bonding portion.

[0071] <Application Example 4>

[0072] The semiconductor substrate according to any one of Application Examples 1 to 3, wherein

[0073] The metal member is formed of an alloy of tungsten and copper,

[0074] The conductive film is formed of copper.

Claims

1. A semiconductor substrate, wherein: The semiconductor substrate has: Base material; A metal component, which includes a non-magnetic material and has non-magnetic properties; a conductive film formed on the metal member, the conductive film comprising the same material as the non-magnetic material contained in the metal member; as well as A bonding portion bonds the side of the metal member on which the conductive film is formed to the base material, and the bonding portion is formed of a non-magnetic material.

2. The semiconductor substrate according to claim 1, wherein The substrate has: an insulating member formed of a non-magnetic material; and A non-magnetic film is formed on the insulating member.

3. The semiconductor substrate according to claim 1 or 2, wherein: The semiconductor substrate further includes a barrier film formed between the conductive film and the bonding portion.

4. The semiconductor substrate according to claim 1 or 2, wherein: The metal member is formed of an alloy of tungsten and copper, The conductive film is formed of copper.

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