CN115956144A

CN115956144A - Method for producing metal-filled microstructure

Info

Publication number: CN115956144A
Application number: CN202180050316.XA
Authority: CN
Inventors: 川口顺二; 堀田吉则
Original assignee: Fujifilm Corp
Current assignee: Fujifilm Corp
Priority date: 2020-08-24
Filing date: 2021-07-13
Publication date: 2023-04-11
Also published as: WO2022044585A1; TW202208695A; JPWO2022044585A1; KR20230043153A

Abstract

The invention provides a method for manufacturing a metal-filled microstructure having good conductivity. The method for producing a metal-filled microstructure comprises: a preparation step of preparing a structure having an insulating film and a plurality of conductors penetrating the insulating film in a thickness direction and being provided in an electrically insulated state from each other, the conductors protruding from at least one surface of the insulating film in the thickness direction, the structure having a resin layer covering the surface of the insulating film from which the conductors protrude; a heating step of heating at least the resin layer in an atmosphere having an oxygen partial pressure of 10000Pa or less; and a removing step of removing the resin layer heated by the heating step from the insulating film. The resin layer contains a heat-peelable adhesive.

Description

Method for producing metal-filled microstructure

Technical Field

The present invention relates to a method for manufacturing a metal-filled microstructure, the method comprising: the present invention relates to a method for manufacturing a metal-filled microstructure, in which a plurality of conductors penetrating in a thickness direction of an anodized film and being electrically insulated from each other protrude from at least one surface of the anodized film in the thickness direction, and a resin layer covering the surface of the anodized film from which the conductors protrude is removed after heating, and in particular, the resin layer is heated in an atmosphere having an oxygen partial pressure of 10000Pa or less.

Background

A structure in which a plurality of through holes provided in an insulating base material are filled with a conductive material such as a metal is one of fields that have recently attracted attention also in nanotechnology, and applications as an anisotropic conductive member, for example, are expected.

Anisotropic conductive members are widely used as electrical connection members for electronic components such as semiconductor elements, inspection connectors for functional inspection, and the like, because they are inserted between electronic components such as semiconductor elements and circuit boards, and electrical connection between the electronic components and the circuit boards is obtained only by applying pressure.

In particular, the miniaturization of electronic components such as semiconductor elements is remarkable. In a direct connection wiring board system such as conventional wire bonding, flip chip bonding, thermocompression bonding, and the like, sufficient stability of electrical connection of electronic components may not be ensured, and therefore anisotropic conductive members have attracted attention as electronic connection members.

As a method for producing an anisotropic conductive member, for example, patent document 1 describes a method for producing a metal-filled microstructure, which comprises: an anodic oxidation treatment step of forming an anodic oxide film by subjecting one surface of the aluminum substrate to an anodic oxidation treatment and forming a barrier layer having micropores in a thickness direction and a bottom portion of the micropores on the one surface of the aluminum substrate; a barrier layer removing step of removing a barrier layer of the anodized film using an alkaline aqueous solution containing a metal M1 having a higher overvoltage than aluminum after the anodizing treatment step; a metal filling step of performing electrolytic plating treatment to fill the inside of the micropores with a metal M2 after the barrier layer removing step; and a substrate removal step for removing the aluminum substrate after the metal filling step to obtain a metal-filled microstructure. Patent document 1 discloses a resin layer forming step of forming a resin layer on the surface of the anodized film on the side where the aluminum substrate is not provided, after the metal filling step and before the substrate removing step.

Prior art documents

Patent literature

Patent document 1: japanese patent No. 6535098

Disclosure of Invention

Technical problem to be solved by the invention

In patent document 1, a resin layer is provided on the surface of the anodized film on the side where the aluminum substrate is not provided. The metal-filled microstructure is used to electrically connect 2 semiconductor chips, for example. In this case, the resin layer needs to be peeled. As described above, when the metal-filled microstructure of patent document 1 is used for electrically connecting 2 semiconductor chips, the conductivity between the semiconductor chips may be insufficient. A metal-filled microstructure having good electrical conductivity is required.

The purpose of the present invention is to provide a method for producing a metal-filled microstructure having good conductivity.

Means for solving the technical problems

In order to achieve the above object, one aspect of the present invention provides a method for manufacturing a metal-filled microstructure, including: a preparation step of preparing a structure having an insulating film and a plurality of conductors provided in a state of penetrating the insulating film in a thickness direction and being electrically insulated from each other, the conductors protruding from at least one surface of the insulating film in the thickness direction, the structure having a resin layer covering the surface of the insulating film from which the conductors protrude; a heating step of heating at least the resin layer in an atmosphere having an oxygen partial pressure of 10000Pa or less; and a removing step of removing the resin layer heated by the heating step from the insulating film, the resin layer containing a heat-peelable adhesive.

In the heating step, the oxygen partial pressure of the atmosphere is preferably 1.0Pa or less.

In the heating step, the partial pressure of the inert gas in the atmosphere is preferably 85% or more of the total pressure of the atmosphere.

In the heating step, the partial pressure of the reducing gas in the atmosphere is preferably 85% or more of the total pressure of the atmosphere.

In the heating step, the total pressure of the atmosphere is preferably 5.0Pa or less.

The conductor preferably comprises a base metal.

The plurality of conductors preferably have a cross-sectional area of 20 μm in a cross-section perpendicular to the longitudinal direction of the conductors ² The following conductors.

The temperature at which the resin layer reaches in the heating step is preferably 150 ℃ or lower.

The conductor preferably protrudes from each of both surfaces of the insulating film in the thickness direction, and the resin layers are preferably provided on each of both surfaces of the insulating film in the thickness direction.

The insulating film is preferably an anodic oxide film.

Effects of the invention

According to the present invention, a metal-filled microstructure having good conductivity can be obtained.

Drawings

Fig. 1 is a schematic cross-sectional view showing one step of an example of a method for producing a metal-filled microstructure according to an embodiment of the present invention.

Fig. 2 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 3 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 5 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 6 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 7 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 8 is a schematic cross-sectional view showing one step of an example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 9 is a schematic cross-sectional view showing a step of another example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 10 is a schematic cross-sectional view showing a step of another example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 11 is a schematic cross-sectional view showing a step of another example of the method for producing a metal-filled microstructure according to the embodiment of the present invention.

Fig. 12 is a schematic perspective view showing an example of a supply method of the anisotropic conductive member according to the embodiment of the present invention.

Fig. 13 is a schematic perspective view showing an example of a supply method of the anisotropic conductive member according to the embodiment of the present invention.

Fig. 14 is a schematic diagram showing an example of a joined body using a metal-filled microstructure according to an embodiment of the present invention.

Detailed Description

Hereinafter, a method for producing a metal-filled microstructure according to the present invention will be described in detail based on preferred embodiments shown in the drawings.

The drawings described below are exemplary drawings for describing the present invention, and the present invention is not limited to the drawings described below.

In addition, "to" in the following numerical ranges means to include numerical values described on both sides. E.g. epsilon _a Is a numerical value of alpha _b Value of beta _c Denotes epsilon _a Includes the value of alpha _b And a value of beta _c When expressed by a mathematical notation, the range of (1) is α _b ≤ε _a ≤β _c 。

The temperature and time include error ranges that are generally acceptable in the corresponding technical fields unless otherwise specified.

Further, unless otherwise specified, the parallelism and the like include an error range that is generally allowable in the corresponding technical field.

[ Metal-filled microstructure ]

Fig. 1 to 8 are schematic cross-sectional views showing an example of a method for producing a metal-filled microstructure according to an embodiment of the present invention in order of steps.

As shown in fig. 8, the metal-filled microstructure 10 includes, for example: an insulating film 12 having electrical insulation properties; and a plurality of conductors 14 penetrating the insulating film 12 in the thickness direction Dt and provided in a state of being electrically insulated from each other. The conductor 14 protrudes from at least one surface of the insulating film 12 in the thickness direction Dt. When the conductor 14 protrudes from at least one surface of the insulating film 12 in the thickness direction Dt, the conductor preferably protrudes from the front surface 12a or the back surface 12b in a structure protruding from one surface. In the metal-filled microstructure 10, the insulating film 12 is formed of, for example, an anodic oxide film 15.

The plurality of conductors 14 are disposed on the insulating film 12 in a state of being electrically insulated from each other. In this case, for example, the insulating film 12 has a plurality of pores 13 penetrating in the thickness direction Dt. Conductors 14 are provided in the plurality of pores 13. The conductor 14 protrudes from the surface 12a in the thickness direction Dt of the insulating film 12.

The metal-filled microstructure 10 has anisotropic conductivity in which the conductors 14 are arranged in an electrically insulated state from each other. The metal-filled microstructure 10 has conductivity in the thickness direction Dt, but has sufficiently low conductivity in the direction parallel to the surface 12a of the insulating film 12.

The outer shape of the metal-filled microstructure 10 is not particularly limited, and is, for example, a square or a circle. The outer shape of the metal-filled microstructure 10 can be formed into a shape corresponding to the application, ease of production, and the like.

[ method for producing Metal-filled microstructure ]

In an example of the method for producing a metal-filled microstructure, a case where the insulating film is formed of an anodized aluminum film will be described as an example. In order to form an anodized film of aluminum, an aluminum substrate is used. Therefore, in one example of the method for manufacturing the structure, first, as shown in fig. 1, the aluminum substrate 30 is prepared.

The size and thickness of the aluminum substrate 30 are determined as appropriate depending on the thickness of the insulating film 12 of the metal-filled microstructure 10 (see fig. 8) to be finally obtained, the device to be processed, and the like. The aluminum substrate 30 is, for example, a rectangular plate. Further, the metal substrate is not limited to the aluminum substrate, and a metal substrate capable of forming the electrically insulating film 12 may be used.

Next, one surface 30a (see fig. 1) of the aluminum substrate 30 is anodized. As a result, one surface 30a (see fig. 1) of the aluminum substrate 30 is anodized to form an anodized film 15, which is an insulating film 12 having a plurality of pores 13 extending in the thickness direction Dt of the aluminum substrate 30 as shown in fig. 2. A barrier layer 31 is present at the bottom of each pore 13. The step of performing the anodic oxidation is referred to as an anodic oxidation treatment step.

In the insulating film 12 having the plurality of pores 13, the barrier layer 31 is present at the bottom of each pore 13 as described above, but the barrier layer 31 shown in fig. 2 is removed. Thereby, the insulating film 12 having the plurality of pores 13 without the barrier layer 31 is obtained (refer to fig. 3). The step of removing the barrier layer 31 is referred to as a barrier layer removal step.

In the barrier layer removing step, an alkaline aqueous solution containing ions of the metal M1 having a higher overvoltage than aluminum is used to remove the barrier layer 31 of the insulating film 12, and at the same time, a metal layer 35a (see fig. 3) made of the metal (metal M1) is formed on the surface 32d (see fig. 3) of the bottom 32c (see fig. 3) of the pore 13. Thus, the aluminum substrate 30 exposed in the pores 13 is covered with the metal layer 35a. This makes it easy to perform electroplating when filling metal in the fine holes 13 by electroplating, and suppresses insufficient filling of metal in the fine holes, and thus suppresses failure in formation of the conductor 14.

In addition, the alkaline aqueous solution containing the ion of the above metal M1 may further contain a compound containing an aluminum ion (sodium aluminate, aluminum hydroxide, aluminum oxide, etc.). The content of the compound containing aluminum ions is preferably 0.1 to 20g/L, more preferably 0.3 to 12g/L, and further preferably 0.5 to 6g/L in terms of the amount of aluminum ions.

Next, electroplating is performed from the surface 12a of the insulating film 12 having the plurality of pores 13 extending in the thickness direction Dt. In this case, the metal layer 35a can be used as an electrode for electrolytic plating. The metal 35b is used for plating, and plating is performed with the metal layer 35a formed on the surface 32d (see fig. 3) of the bottom 32c (see fig. 3) of the fine pore 13 as a starting point. Thereby, as shown in fig. 4, the metal 35b constituting the conductor 14 is filled in the pores 13 of the insulating film 12. The conductor 14 having conductivity can be formed by filling the metal 35b into the fine pores 13. In addition, the metal layer 35a and the metal 35b are collectively referred to as filled metal 35.

The step of filling the metal 35b into the pores 13 of the insulating film 12 is referred to as a metal filling step. As described above, the conductor 14 is not limited to being made of metal, and a conductive material can be used. In the metal filling step, electrolytic plating is used, and the metal filling step will be described in detail later. The surface 12a of the insulating film 12 corresponds to one surface of the insulating film 12.

After the metal filling step, as shown in fig. 5, after the metal filling step, a portion of the surface 12a of the insulating film 12 on the side where the aluminum substrate 30 is not provided is removed in the thickness direction Dt, and the metal 35 filled in the metal filling step is made to protrude from the surface 12a of the insulating film 12. That is, the conductor 14 is made to protrude from the surface 12a of the insulating film 12. Thereby, the protruding portion 14a can be obtained. The step of projecting the conductor 14 beyond the surface 12a of the insulating film 12 is referred to as a surface metal projecting step.

After the surface metal protruding step, the resin layer 16 as shown in fig. 6 is formed on the surface 12a of the insulating film 12 of the conductor 14 on which the protruding portion 14a is formed. Thus, the surface of the insulating film from which the conductor protrudes is covered with the resin layer, thereby obtaining the structure 18. The step of preparing the structure 18 is referred to as a preparation step.

The step of forming the resin layer 16 covering the surface of the insulating film 12 from which the conductor 14 protrudes is referred to as a resin layer forming step. The resin layer 16 contains a heat-peelable adhesive.

After the resin layer forming process, the aluminum substrate 30 is removed from the structural body 18 as shown in fig. 7. The process of removing the aluminum member 30 is referred to as a substrate removal process.

Next, at least the resin layer 16 is heated in an atmosphere having an oxygen partial pressure of 10000Pa or less with respect to the structure 18. The step of heating the resin layer 16 is referred to as a heating step.

In the heating step, a heating apparatus for a semiconductor wafer used for manufacturing a semiconductor element can be used.

The heating step is performed in a metal container used when a semiconductor wafer is heated in a semiconductor manufacturing apparatus, for example. The structure 18 after substrate removal is disposed in a container, and the oxygen partial pressure in the container is set to 10000Pa or less.

The total pressure and the partial pressure of the atmosphere in the heating step can be measured using, for example, a manometer. Thereby, the above-mentioned oxygen partial pressure can be measured. Further, the partial pressure of the inert gas and the partial pressure of the reducing gas, which will be described later, can also be measured.

The oxygen partial pressure can be adjusted by degassing, for example.

The heating step is not limited to an atmosphere having an oxygen partial pressure of 10000Pa or less. The temperature at which the resin layer reaches in the heating step is preferably 150 ℃ or lower. When the temperature of the resin layer in the heating step is 150 ℃ or lower, the conductivity is improved.

Next, as shown in fig. 8, the resin layer 16 heated by the heating step is removed from the insulating film 12. Thereby, the metal-filled microstructure 10 is obtained.

The step of removing the resin layer 16 from the insulating film 12 is referred to as a removal step. In the removing step, a method of removing the resin layer 16 is not particularly limited, and for example, the resin layer is removed by using a tool such as a nipper. In the removal step, the insulating film 12 may be peeled off from the resin layer 16 using a tool such as a pincer. The atmosphere in the removing step does not need to be the same as the atmosphere in the heating step, and may be, for example, an atmospheric atmosphere.

Fig. 9 to 11 are schematic cross-sectional views showing another example of the method for producing a metal-filled microstructure according to the embodiment of the present invention in the order of steps.

After the substrate removing step shown in fig. 7, as shown in fig. 9, the rear surface 12b of the insulating film 12 on the side where the aluminum substrate 30 is provided is partially removed in the thickness direction Dt, and the conductor 14, which is the metal 35 filled in the metal filling step, is made to protrude from the rear surface 12b of the insulating film 12. Thereby, the protruding portion 14b can be obtained.

The front metal projecting step and the back metal projecting step may be a two-step method, or may be a method including one of the front metal projecting step and the back metal projecting step. The surface metal protruding step and the back metal protruding step correspond to "protruding steps", and both the surface metal protruding step and the back metal protruding step are protruding steps.

As shown in fig. 9, the structure 18 may have a structure having a protruding portion 14a and a protruding portion 14b that protrude from the front surface 12a and the back surface 12b of the insulating film 12, i.e., from both the surface conductors 14 in the thickness direction Dt of the insulating film 12.

As shown in fig. 10, a resin layer 16 is formed on the back surface 12b of the insulating film 12 shown in fig. 9, and the resin layer 16 is provided on each surface of the anodized film in the thickness direction Dt.

Next, the heating step and the removal step of the resin layer 16 are performed on the structure 18, and the metal-filled microstructure 10 having the protruding

portions

14a and 14b shown in fig. 11 is obtained.

In the barrier layer removing step, the barrier layer is removed using an alkaline aqueous solution containing ions of the metal M1 having a higher overvoltage than aluminum, whereby not only the barrier layer 31 is removed, but also the metal layer 35a of the metal M1 which is less likely to generate hydrogen gas than aluminum is formed on the aluminum substrate 30 exposed at the bottom of the pores 13. As a result, the in-plane uniformity of the metal filling becomes good. It is considered that generation of hydrogen gas by the plating solution can be suppressed and metal filling by electrolytic plating can be easily performed.

Further, it was found that the uniformity of metal filling during the plating treatment was greatly optimized by providing a holding step in the barrier layer removing step, the holding step being held for a total of 5 minutes or more at a voltage of 95% or more and 105% or less of a voltage (holding voltage) selected from a range of less than 30% of the voltage in the anodizing treatment step, and by using an alkaline aqueous solution containing ions of the metal M1 in combination. Therefore, it is preferable to have a holding step.

Although the detailed mechanism is not clear, the reason is considered as follows: in the barrier layer removing step, the metal M1 layer is formed under the barrier layer by using an alkaline aqueous solution containing metal M1 ions, whereby damage to the interface between the aluminum substrate and the anodic oxide film can be suppressed, and the dissolution uniformity of the barrier layer can be improved.

In the barrier layer removing step, the metal layer 35a made of the metal (metal M1) is formed at the bottom of the pores 13, but the present invention is not limited thereto, and only the barrier layer 31 is removed to expose the aluminum substrate 30 at the bottom of the pores 13. The aluminum substrate 30 can be used as an electrode for electrolytic plating with the aluminum substrate 30 exposed.

[ anodic oxide film ]

For the reason that pores having a desired average diameter are formed as described above and a conductor is easily formed, an anodized film of aluminum, for example, is used. However, the anodic oxide film of the valve metal can be used without being limited to the anodic oxide film of aluminum. Therefore, the metal substrate uses a valve metal.

Specific examples of the valve metal include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Among them, an anodized film of aluminum is preferable from the viewpoint of good dimensional stability and low cost. Therefore, it is preferable to manufacture the structure using an aluminum substrate.

The thickness of the anodic oxide film is the same as the thickness ht of the insulating film 12.

[ Metal base plate ]

The metal substrate is used for manufacturing a structure, and is a substrate for forming an anodic oxide film. As the metal substrate, for example, a metal substrate on which an anodic oxide film can be formed as described above can be used, and a substrate made of the valve metal described above can be used. For example, as described above, the metal substrate is an aluminum substrate because an anodized film is easily formed as the anodized film.

[ aluminum substrate ]

The aluminum substrate used for forming the insulating film 12 is not particularly limited, and specific examples thereof include: a pure aluminum plate; an alloy plate containing aluminum as a main component and a trace amount of a foreign element; a substrate on which high-purity aluminum is vapor-deposited on low-purity aluminum (e.g., recycled material); a substrate coated with high purity aluminum by a method such as vapor deposition or sputtering on the surface of a silicon wafer, quartz, glass, or the like; a resin substrate laminated with aluminum, and the like.

In the aluminum substrate, the surface on the side where the anodized film is formed by the anodization has an aluminum purity of preferably 99.5 mass% or more, more preferably 99.9 mass% or more, and still more preferably 99.99 mass% or more. If the aluminum purity is within the above range, the regularity of the micropore arrangement becomes sufficient.

The aluminum substrate is not particularly limited as long as it can form an anodic oxide film, and for example, a JIS (Japanese Industrial Standards) 1050 material is used.

The surface of the aluminum substrate on the side to be anodized is preferably subjected to heat treatment, degreasing treatment, and mirror finish treatment in advance.

Here, the heat treatment, degreasing treatment, and mirror finishing treatment can be performed in the same manner as the respective treatments described in paragraphs [0044] to [0054] of japanese patent application laid-open No. 2008-270158.

The mirror finishing treatment before the anodic oxidation treatment is, for example, electrolytic polishing in which an electrolytic polishing liquid containing phosphoric acid is used.

[ anodic Oxidation treatment Process ]

The anodization can be performed by a conventionally known method, but it is preferable to use a self-ordering method or a constant-pressure treatment in order to improve the order of the micropore arrangement and ensure the anisotropic conductivity of the structure.

Here, the same processing as each of the processing described in paragraphs [0056] to [0108] and [ fig. 3] of jp 2008-270158 a can be performed with respect to the self-ordering method and the constant voltage processing of the anodic oxidation treatment.

[ maintenance procedure ]

The method for manufacturing a structure may include a holding step. The holding step is as follows: after the anodizing step, the metal sheet is held at a voltage of 95% to 105% of a holding voltage selected from a range of 1V or more and less than 30% of the voltage in the anodizing step for a total of 5 minutes or more. In other words, the holding step is a step of: after the anodizing step, the electrolytic treatment is performed for 5 minutes or longer in total at a voltage of 95% to 105% of a holding voltage selected from a range of 1V or more and less than 30% of a voltage in the anodizing step.

Here, the "voltage in the anodic oxidation treatment" is a voltage applied between the aluminum and the counter electrode, and for example, if the electrolysis time based on the anodic oxidation treatment is 30 minutes, it means an average value of the voltages held during 30 minutes.

The voltage in the holding step is preferably 5% to 25% of the voltage in the anodization, and more preferably 5% to 20% of the voltage in terms of controlling the thickness of the barrier layer to an appropriate thickness with respect to the sidewall thickness of the anodized film, that is, the depth of the pores.

From the viewpoint of further improving the in-plane uniformity, the total retention time in the holding step is preferably 5 minutes to 20 minutes, more preferably 5 minutes to 15 minutes, and still more preferably 5 minutes to 10 minutes.

The holding time in the holding step may be 5 minutes or more in total, and is preferably 5 minutes or more continuously.

The voltage in the holding step may be set to decrease continuously or stepwise from the voltage in the anodizing step to the voltage in the holding step, but for the reason of further improving the in-plane uniformity, it is preferable to set the voltage to 95% to 105% of the holding voltage within 1 second after the end of the anodizing step.

The holding step may be performed continuously with the anodizing step, for example, by lowering the electrolytic potential at the end of the anodizing step.

The conditions other than the electrolytic potential can be the same as the electrolytic solution and the treatment conditions used in the conventional anodizing treatment.

In particular, when the holding step and the anodic oxidation treatment step are continuously performed, it is preferable to perform the treatment using the same electrolytic solution.

In the anodized film having a plurality of micropores, as described above, a barrier layer (not shown) is present at the bottoms of the micropores. There is a barrier layer removing step of removing the barrier layer.

[ Barrier layer removal Process ]

The barrier layer removing step is a step of removing the barrier layer of the anodic oxide film using an alkaline aqueous solution containing a metal M1 ion having a higher overvoltage than aluminum, for example.

In the barrier layer removing step, the barrier layer is removed, and a conductor layer made of the metal M1 is formed at the bottom of the micropore.

Here, hydrogen overvoltage (hydrogen overvoltage) refers to a voltage required for generating hydrogen, and for example, aluminum (Al) has a hydrogen overvoltage of-1.66V (journal of the japanese society of chemistry, 1982, (8), p 1305-1313). In addition, examples of the metal M1 having a higher hydrogen overvoltage than aluminum and hydrogen overvoltage values thereof are shown below.

Platinum (Pt): 0.00V

Gold (Au): 0.02V

Silver (Ag): 0.08V

Nickel (Ni): 0.21V

Copper (Cu): 0.23V

Tin (Sn): 0.53V

Zinc (Zn): 0.70V

In the present invention, the metal M1 used in the barrier layer removing step is preferably a metal having a higher ionization tendency than the metal M2 used in the metal filling step described later, because the metal M2 filled in the anodizing step described later causes a substitution reaction and has little influence on the electrical characteristics of the metal filled in the micropores.

Specifically, when copper (Cu) is used as the metal M2 in the metal filling step described later, examples of the metal M1 used in the barrier layer removing step include Zn, fe, ni, and Sn, and among these, zn and Ni are preferably used, and Zn is more preferably used.

When Ni is used as the metal M2 in the metal filling step described later, examples of the metal M1 used in the barrier layer removing step include Zn and Fe, and among these, zn is preferably used.

The method for removing the barrier layer using an alkaline aqueous solution containing the metal M1 is not particularly limited, and examples thereof include a method similar to a conventionally known chemical etching treatment.

< chemical etching treatment >

The barrier layer can be removed by chemical etching, for example, by a method of immersing the structure after the anodization step in an alkaline aqueous solution, filling the inside of the micropores with the alkaline aqueous solution, and then bringing the opening-side surfaces of the micropores of the anodized film into contact with a pH buffer solution, thereby selectively dissolving only the barrier layer.

Here, as the alkaline aqueous solution containing the metal M1, at least one alkaline aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide is preferably used. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 10 to 60 ℃, more preferably 15 to 45 ℃, and still more preferably 20 to 35 ℃.

Specifically, for example, a 50g/L phosphoric acid aqueous solution at 40 ℃, a 0.5g/L sodium hydroxide aqueous solution at 30 ℃, a 0.5g/L potassium hydroxide aqueous solution at 30 ℃ and the like can be preferably used.

As the pH buffer, a buffer corresponding to the above-mentioned alkaline aqueous solution can be suitably used.

The immersion time in the alkaline aqueous solution is preferably 5 to 120 minutes, more preferably 8 to 120 minutes, still more preferably 8 to 90 minutes, and particularly preferably 10 to 90 minutes. Among them, it is preferably 10 to 60 minutes, and more preferably 15 to 60 minutes.

The pores 13 may be formed by expanding micropores and removing a barrier layer. In this case, a hole expanding process may be used for expanding the micropores. The pore-enlarging treatment is a treatment for dissolving the anodic oxide film and enlarging the pore diameter of the micropores by immersing the anodic oxide film in an acidic aqueous solution or an alkaline aqueous solution, and an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, or hydrochloric acid, or a mixture thereof, or an aqueous solution of sodium hydroxide, potassium hydroxide, lithium hydroxide, or the like can be used for the pore-enlarging treatment.

In addition, the barrier layer at the bottom of the micropores may be removed in the pore-enlarging treatment, and the micropores are expanded in diameter and the barrier layer is removed by using an aqueous solution of sodium hydroxide in the pore-enlarging treatment.

[ Metal filling Process ]

< Metal used in Metal filling step >

In the metal filling step, the metal filled as a conductor inside the fine pores 13 for forming a conductor and the metal constituting the metal layer preferably have a resistivity of 10 ³ Materials of not more than Ω · cm. Specific examples of the metal include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), zinc (Zn), and the like.

In addition, the conductor is preferably copper (Cu), gold (Au), aluminum (Al), or nickel (Ni), more preferably copper (Cu) or gold (Au), and still more preferably copper (Cu), from the viewpoint of conductivity and formation by an electroplating method.

< electroplating method >

As the plating method for filling the inside of the pores with the metal, for example, an electrolytic plating method or a non-electrolytic plating method can be used.

Here, in the conventionally known electrolytic plating method used for coloring and the like, it is difficult to selectively deposit (grow) a metal in a hole with a high aspect ratio. The reason for this is considered to be that the plating layer does not grow even if the deposited metal is consumed in the pores and electrolysis is performed for a predetermined time or longer.

Therefore, in the case of filling metal by electrolytic plating, it is necessary to set a pause time in pulse electrolysis or constant potential electrolysis. The stop time is 10 seconds or more, preferably 30 to 60 seconds.

In addition, it is also desirable to apply ultrasonic waves in order to promote stirring of the electrolytic solution.

The electrolytic voltage is usually 20V or less, preferably 10V or less, but it is preferable to measure the deposition potential of the target metal in the electrolyte solution used in advance and perform constant potential electrolysis within the potential + 1V. In the case of performing constant potential electrolysis, it is preferable to use cyclic voltammetry in combination, and potentiostat devices such as Solartron, BAS inc, HOKUTO DENKO corp, IVIUM, and the like can be used.

(plating solution)

As the plating liquid, conventionally known plating liquids can be used.

Specifically, when copper is deposited, an aqueous copper sulfate solution is usually used, but the concentration of copper sulfate is preferably 1 to 300g/L, more preferably 100 to 200g/L. Further, when hydrochloric acid is added to the electrolytic solution, precipitation can be promoted. In this case, the hydrochloric acid concentration is preferably 10 to 20g/L.

When gold is deposited, electroplating is preferably performed by alternating current electrolysis using a sulfuric acid solution of tetrachlorogold.

The plating solution preferably contains a surfactant.

As the surfactant, a known surfactant can be used. Sodium lauryl sulfate, which has been known as a surfactant added to a plating liquid in the past, can also be used as it is. The hydrophilic portion can be used both as an ionic (cationic/anionic/amphoteric) substance and a nonionic (nonionic) substance, but from the viewpoint of avoiding generation of bubbles on the surface of the plating object, the cationic surfactant is preferable. The concentration of the surfactant in the composition of the plating liquid is desirably 1% by mass or less.

In addition, in the electroless plating method, since it takes a long time to completely fill the pores composed of the pores having a high aspect ratio with the metal, it is desirable to fill the pores with the metal by the electrolytic plating method.

[ substrate removal Process ]

The substrate removing step is a step of removing the aluminum substrate after the metal filling step. The method for removing the aluminum substrate is not particularly limited, and for example, a method of removing the aluminum substrate by dissolution is preferable.

< dissolution of aluminum substrate >

In the dissolution of the aluminum substrate, it is preferable to use a treatment liquid that does not easily dissolve the anodic oxide film and easily dissolves aluminum.

The dissolution rate of the aluminum in the treatment liquid is preferably 1 μm/min or more, more preferably 3 μm/min or more, and still more preferably 5 μm/min or more. Similarly, the dissolution rate of the anodic oxide film is preferably 0.1 nm/min or less, more preferably 0.05 nm/min or less, and still more preferably 0.01 nm/min or less.

Specifically, the treatment liquid containing at least 1 metal compound having a lower ionization tendency than aluminum and having a pH (hydrogen ion index) of 4 or less or 8 or more is preferable, and the pH is more preferably 3 or less or 9 or more, and further preferably 2 or less or 10 or more.

As the treatment liquid for dissolving aluminum, an acid or alkaline aqueous solution is used as a base, and for example, compounds of manganese, zinc, chromium, iron, cadmium, cobalt, nickel, tin, lead, antimony, bismuth, copper, mercury, silver, palladium, platinum, gold (for example, chloroplatinic acid), fluorides thereof, chlorides thereof, and the like are preferably blended.

Among them, an acidic aqueous solution base is preferable, and a mixed chloride is preferable.

In particular, from the viewpoint of the treatment range, a treatment liquid in which mercury chloride is mixed in an aqueous hydrochloric acid solution (hydrochloric acid/mercury chloride) and a treatment liquid in which copper chloride is mixed in an aqueous hydrochloric acid solution (hydrochloric acid/copper chloride) are preferable.

The composition of the treatment solution in which aluminum is dissolved is not particularly limited, and for example, a bromine/methanol mixture, a bromine/ethanol mixture, aqua regia, or the like can be used.

The acid or alkali concentration of the treatment solution in which aluminum is dissolved is preferably 0.01 to 10mol/L, and more preferably 0.05 to 5mol/L.

The treatment temperature of the treatment solution using dissolved aluminum is preferably-10 to 80 ℃, and preferably 0 to 60 ℃.

The aluminum substrate is dissolved by bringing the aluminum substrate after the plating step into contact with the treatment liquid. The contact method is not particularly limited, and examples thereof include an immersion method and a spraying method. Among them, the dipping method is preferable. The contact time in this case is preferably 10 seconds to 5 hours, and more preferably 1 minute to 3 hours.

In addition, the insulating film 12 may be provided with a support, for example. The support preferably has the same outer shape as the insulating film 12. The workability is improved by mounting the support.

[ projecting procedure ]

In removing a part of the insulating film 12, for example, a metal that does not dissolve the conductor 14 and aluminum oxide (Al) that is the insulating film 12 may be dissolved ₂ O ₃ ) An acidic aqueous solution or a basic aqueous solution. A part of the insulating film 12 is removed by bringing the above-described acidic aqueous solution or alkaline aqueous solution into contact with the insulating film 12 having the pores 13 filled with the metal. The method of bringing the above-mentioned acidic aqueous solution or alkaline aqueous solution into contact with the insulating film 12 is not particularly limited, and examples thereof include a dipping method and a spraying method. Among them, the dipping method is preferable.

When an acidic aqueous solution is used, an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or the like, or a mixture thereof is preferably used. Among them, an aqueous solution containing no chromic acid is preferable from the viewpoint of excellent safety. The concentration of the acidic aqueous solution is preferably 1 to 10% by mass. Preferably, the temperature of the acidic aqueous solution is 25 to 60 ℃.

When an alkaline aqueous solution is used, it is preferable to use at least one alkaline aqueous solution selected from the group consisting of sodium hydroxide, potassium hydroxide, and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the aqueous alkaline solution is preferably 20 to 35 ℃.

Specifically, for example, a 50g/L phosphoric acid aqueous solution at 40 ℃, a 0.5g/L sodium hydroxide aqueous solution at 30 ℃ or a 0.5g/L potassium hydroxide aqueous solution at 30 ℃ is preferably used.

The immersion time in the acidic aqueous solution or the basic aqueous solution is preferably 8 to 120 minutes, more preferably 10 to 90 minutes, and still more preferably 15 to 60 minutes. Here, the dipping time refers to the total of the dipping times when the dipping treatment is repeated for a short time. Further, between the respective immersion treatments, a cleaning treatment may be performed.

The metal 35, i.e., the conductor 14, is protruded from the front surface 12a or the back surface 12b of the insulating film 12, but the conductor 14 is preferably protruded from the front surface 12a or the back surface 12b of the insulating film 12 by 10nm to 1000nm, more preferably by 50nm to 500nm. That is, the amount of protrusion of the protrusion 14a from the front surface 12a of the insulating film 12 and the amount of protrusion of the protrusion 14b from the conductor 14 on the back surface 12b of the insulating film 12 are each preferably 10nm to 1000nm, and more preferably 50nm to 500nm.

The height of the protruding

portions

14a,14b of the conductor 14 is an average value of the height of the protruding portions of the conductor measured at 10 points, when the cross section of the metal-filled microstructure 10 is observed at a magnification of 2 ten thousand times by an electrolytic emission type scanning electron microscope.

When the height of the protruding portion of the conductor 14 is strictly controlled, it is preferable that the inside of the fine pore 13 is filled with a conductive material such as a metal, the insulating film 12 and the end portion of the conductive material such as a metal are processed to be flush with each other, and then the anodic oxide film is selectively removed.

After the metal is filled or after the protrusion step, heat treatment can be performed to reduce the strain in the conductor 14 caused by the metal filling.

From the viewpoint of suppressing the metal oxidation, the heat treatment is preferably performed in a reducing atmosphere, specifically, preferably under the condition that the oxygen concentration is 20Pa or less, and more preferably under vacuum. Here, the vacuum refers to a state of a space in which at least one of the gas density and the gas pressure is lower than the atmospheric air.

For the purpose of correction, it is preferable to perform heat treatment while applying stress to the insulating film 12.

[ resin layer Forming step ]

As described above, the process is a step of forming a resin layer covering the surface of the insulating film from which the conductor protrudes. The resin layer is provided to protect the conductor and improve the conveyance property.

The resin layer forming step is a step performed after the metal filling step, after the surface metal protruding step, and before the substrate removing step.

As described above, the resin layer contains a heat-peelable adhesive. From the viewpoint of transportability and ease of use as an anisotropic conductive member, the resin layer is more preferably a film with an adhesive layer which is weakened in adhesiveness by heat treatment and is peelable.

The method for sticking the above-mentioned film with an adhesive layer is not particularly limited, and sticking can be performed using a conventionally known surface protective tape sticking apparatus or laminator.

The film with an adhesive layer, which has weakened adhesiveness by the heat treatment and can be peeled, includes a heat-peelable resin layer.

Here, the thermally peelable resin layer has adhesive strength at normal temperature and can be easily peeled off only by heating, and therefore, foamable microcapsules and the like are mainly used in many cases.

Specific examples of the adhesive constituting the adhesive layer include rubber adhesives, acrylic adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, and styrene-diene block copolymer adhesives.

Examples of commercially available products of the heat-peelable resin layer include Intellimer (registered trademark) tapes (manufactured by NITTA Corporation) such as WS5130C02 and WS5130C 10; somatac (registered trademark) TE series (manufactured by SOMAR corporation); no.3198, no.3198LS, no.3198M, no.3198MS, no.3198H, no.3195, no.3196, no.3195M, no.3195MS, no.3195H, no.3195HS, no.3195V, no.3195VS, no.319Y-4L, no.319Y-4LS, no.319Y-4M, no.319Y-4MS, no.319Y-4H, no.319Y-4HS, no.319Y-4LSC, no.31935MS, no.31935HS, no.3193M, no.3193MS and the like Riva Alpha series (manufactured by NITTO DENKO CORATION) and the like.

[ heating procedure ]

The heating step is a step for removing the resin layer easily. When the resin layer is simply heated, a metal species constituting the conductor may be oxidized to increase the resistance. Therefore, when a metal-filled microstructure is used for an anisotropic conductive member and a semiconductor chip is electrically connected, the conductivity may be reduced. However, by performing the heating step in an atmosphere having an oxygen partial pressure of 10000Pa or less, the increase in resistance is suppressed, and when the semiconductor chip is electrically connected, the conductivity is improved.

In the heating step, the oxygen partial pressure of the atmosphere is 10000Pa or less, preferably 1.0Pa or less. When the oxygen partial pressure is 10000Pa or less, oxidation of the conductor is suppressed, and the smaller the oxygen partial pressure is, oxidation is suppressed regardless of the metal type of the conductor, which is preferable.

The heating step can be performed in an atmosphere described below. For example, when the total pressure of the atmosphere is 100%, the partial pressure of the inert gas in the atmosphere is preferably 85% or more of the total pressure of the atmosphere. When the partial pressure of the inert gas in the atmosphere is 85% or more of the total pressure, the partial pressure of oxygen can be relatively reduced, and oxidation of the conductor can also be suppressed.

The partial pressure of the inert gas can be adjusted by, for example, adjusting the amount of the inert gas supplied into the vessel in which the heating step is performed.

In the heating step, for example, when the total pressure of the atmosphere is 100%, the partial pressure of the reducing gas in the atmosphere is preferably 85% or more of the total pressure of the atmosphere. When the partial pressure of the reducing gas in the atmosphere is 85% or more of the total pressure, the oxygen partial pressure can be relatively reduced, and the oxidation of the conductor can also be suppressed. The reducing gas is preferably a gas that has little reaction with the conductor.

The partial pressure of the reducing gas can be adjusted by, for example, adjusting the amount of the reducing gas supplied into the container in which the heating step is performed.

< inert gas >

The inert gas is not particularly limited, and examples thereof include rare gases such as helium, neon, and argon, and nitrogen. The inert gas may be used alone or in combination with at least 2 kinds of gases.

< reducing gas >

The reducing gas is not particularly limited, and is, for example, hydrogen, carbon monoxide or CH ₄ 、C ₃ H ₈ Or C ₄ H _1o And the like hydrocarbon gases. The reducing gas may be used alone or in combination with at least 2 kinds of gases.

The total pressure of the atmosphere in the heating step is preferably 5.0Pa or less. When the total pressure of the atmosphere in the heating step is 5.0Pa or less, the partial pressure of oxygen in the atmosphere is reduced, and oxidation of the conductor can be suppressed, which is preferable. The total pressure of the atmosphere can be set to 5.0Pa or less by reducing the pressure in the container using a vacuum pump, for example.

< atmosphere of heating step >

The atmosphere in the heating step may be degassed to reduce the oxygen partial pressure as described above, or the atmosphere may be replaced with an inert gas or a reducing gas.

The heating conditions in the heating step are preferably 80 to 350 ℃, more preferably 90 to 250 ℃, and most preferably 100 to 200 ℃. In addition, the reaching temperature of the resin layer in the heating step is preferably 150 ℃ or lower. In the heating step, if the temperature is lower than the above temperature range, the resin layer is less likely to be peeled off. On the other hand, when the temperature is high, oxidation of the filler metal, that is, oxidation of the conductor proceeds, and the filler metal causes defects such as streaks and cracks in the structure.

[ removal Process ]

After the heating step, the resin layer is removed. The removal step is not particularly limited as long as the resin layer can be removed.

Further, the atmosphere in the removing step does not need to be the same as that in the heating step, and the removing step may be performed in an atmospheric atmosphere after the resin layer is heated, for example, in a container used in the heating step.

< other production Processes >

A part of the surface of the aluminum substrate may be subjected to an anodizing treatment using a mask layer of a desired shape.

[ winding Process ]

The structure 18 shown in fig. 7 with the substrate removed is a structure in which the substrate is wound around a winding core 21 and supplied in a roll form as shown in fig. 12. For example, when the metal-filled microstructure 10 is used as an anisotropic conductive member, the resin layer 16 is removed by performing the heating step and the removal step of the resin layer 16 (see fig. 13). Thus, for example, the metal-filled microstructure 10 can be used as an anisotropic conductive member.

From the viewpoint of further improving the transportability of the metal-filled microstructure 10, it is preferable to provide a winding step of winding the metal-filled microstructure 10 in a roll shape with the resin layer 16 provided, after the optional resin layer forming step.

Here, the winding method in the winding step is not particularly limited, and examples thereof include a method of winding around a winding core 21 (see fig. 12) having a specific diameter and a specific width.

From the viewpoint of ease of winding in the winding step, the average thickness of the metal-filled microstructure 10 from which the resin layer 16 (see fig. 13) is removed is preferably 30 μm or less, and more preferably 5 to 20 μm. The metal-filled microstructure 10 from which the resin layer was removed was cut in the thickness direction by FIB (Focused Ion Beam), and the cross section thereof was photographed by a field emission scanning electron microscope (FE-SEM) at a magnification of 50000 times to obtain an average thickness as an average value of 10 points to be measured.

[ other treatment procedures ]

The production method of the present invention may further comprise, in addition to the above steps, a polishing step, a surface smoothing step, a protective film formation treatment and a water washing treatment described in paragraphs [0049] to [0057] of International publication No. 2015/029881.

In addition, from the viewpoint of handling properties in manufacturing and the use of the metal-filled microstructure 10 as an anisotropic conductive member, various procedures and forms as shown below can be applied.

< example of procedure using temporary Binder >

In the present invention, after the substrate removing step, a step of fixing the metal-filled microstructure to a silicon wafer using a Temporary Bonding agent (temporal Bonding Materials) and thinning the metal-filled microstructure by polishing may be provided.

Next, after the thin layer process and after the surface is sufficiently cleaned, the surface metal protrusion process can be performed.

Next, after the temporary adhesive agent having a stronger adhesive force than the temporary adhesive agent is applied to the surface from which the metal protrudes and fixed to the silicon wafer, the silicon wafer bonded by the temporary adhesive agent before peeling can be bonded to the surface from which the peeled metal-filled microstructure is from the surface, and the back metal protruding step can be performed.

< example of procedure Using WAX >

In the present invention, after the substrate removing step, a step of fixing the metal-filled microstructure on a silicon wafer using paraffin and polishing the metal-filled microstructure to make the metal-filled microstructure thinner may be provided.

Next, after the temporary adhesive is applied to the surface of the metal protrusion and fixed to the silicon wafer, the silicon wafer is peeled by heating to dissolve the paraffin wax, and the back surface metal protrusion step can be performed on the side surface of the metal-filled microstructure that has been peeled.

Although paraffin wax may be used, improvement in coating thickness uniformity can be achieved by using SKYCOAT (NIKKA SEIKO co., ltd).

< example of procedure conducted after substrate removal treatment >

In the present invention, the following steps may be provided: after the metal filling step and before the substrate removing step, the aluminum substrate is fixed to a rigid substrate (for example, a silicon wafer, a glass substrate, or the like) by using a temporary adhesive, paraffin, or a functional adsorption film, and then the surface of the anodized film on the side where the aluminum substrate is not provided is polished to be thinned.

Next, after a resin material (for example, epoxy resin, polyimide resin, or the like) which is an insulating material is applied to the surface on which the metal is protruded, a rigid substrate can be attached to the surface by the same method as described above. The bonding with the resin material can be performed by selecting a material having a larger adhesive force than that with a temporary adhesive agent or the like, peeling off the rigid substrate initially bonded after the bonding with the resin material, and sequentially performing the substrate removing step, the polishing step, and the back metal protrusion treatment step.

As the functional adsorption film, Q-chuck (registered trademark) (MARUISHI SANGYO co., ltd.) or the like can be used.

In the present invention, the metal-filled microstructure is preferably provided as a product in a state of being bonded to a rigid substrate (for example, a silicon wafer, a glass substrate, or the like) via a peelable layer.

In such a supply method, when the metal-filled microstructure is used as a joining member, the upper and lower devices can be joined by the metal-filled microstructure by temporarily adhering the surface of the metal-filled microstructure to the surface of the device, peeling the rigid substrate, then setting the device to be connected at an appropriate position, and thermally and pressure bonding the device.

Further, a thermal release layer may be used as a releasable layer, or a light release layer may be used in combination with a glass substrate.

In the manufacturing method of the present invention, the steps may be performed individually, or the aluminum coil may be continuously processed as a coil.

In the case of continuous processing, it is preferable to provide appropriate cleaning and drying steps between the respective steps.

The metal-filled microstructure obtained by the production method of the present invention having such various treatment steps is obtained by filling metal into through holes formed in an insulating base material made of an anodic oxide film of an aluminum substrate.

Specifically, by the manufacturing method of the present invention, an anisotropic conductive member described in, for example, japanese patent application laid-open No. 2008-270158, that is, an anisotropic conductive member provided in the following state, can be obtained: in an insulating base material (an anodized film of an aluminum substrate having micropores), a plurality of conductive paths made of a conductive member (metal) penetrate through the insulating base material in a thickness direction in a state of being insulated from each other, and one end of each conductive path is exposed on one surface of the insulating base material and the other end of each conductive path is exposed on the other surface of the insulating base material.

The structure of the metal-filled microstructure will be described in more detail below.

[ insulating film ]

The insulating film 12 is made of a conductive material, and electrically insulates the plurality of conductors 14 from each other. The insulating film 12 has a plurality of pores 13 formed by the conductor 14.

The insulating film is made of, for example, an inorganic material. The insulating film can be, for example, a film having 10 ¹⁴ About omega cmA material of electrical resistivity.

The term "composed of an inorganic material" is defined for distinguishing from a polymer material, and is not limited to the definition of an insulating base material composed only of an inorganic material, but is defined to have an inorganic material as a main component (50 mass% or more). As described above, the insulating film is formed of, for example, an anodic oxide film.

The insulating film may be formed of, for example, a metal oxide, a metal nitride, glass, a ceramic such as silicon carbide or silicon nitride, a carbon base such as diamond-like carbon, polyimide, or a composite material thereof. As the insulating film, for example, a film can be formed by forming an inorganic material containing a ceramic material or a carbon material in an amount of 50 mass% or more on an organic material having through holes.

The length of the insulating film 12 in the thickness direction Dt, that is, the thickness of the insulating film 12, is preferably in the range of 1 to 1000 μm, more preferably in the range of 5 to 500 μm, and still more preferably in the range of 10 to 300 μm. If the thickness of the insulating film 12 is in this range, the handling properties of the insulating film 12 become good.

From the viewpoint of ease of winding, the thickness ht of the insulating film 12 is preferably 30 μm or less, and more preferably 5 to 20 μm.

The thickness of the anodized film was calculated as an average value of 10 points measured by cutting the anodized film in the thickness direction Dt with a Focused Ion Beam (FIB) and taking a surface photograph (5 ten thousand times magnification) of the cross section thereof with a field emission scanning electron microscope (FE-SEM).

The interval between the conductors 14 in the insulating film 12 is preferably 5nm to 800nm, more preferably 10nm to 200nm, and still more preferably 20nm to 60nm. If the interval between the conductors 14 in the insulating film 12 is within the above range, the insulating film 12 functions sufficiently as an electrically insulating partition wall of the conductors 14.

Here, the interval between the conductors means the width between the adjacent conductors, and means the average value of the widths between the adjacent conductors measured at 10 points when the cross section of the metal-filled microstructure 10 is observed at a magnification of 20 ten thousand times by a field emission type scanning electron microscope.

< average diameter of Fine pores >

The average diameter of the pores is preferably 1 μm or less, more preferably 5 to 500nm, still more preferably 20 to 400nm, yet more preferably 40 to 200nm, and most preferably 50 to 100nm. The average diameter d of the fine pores 13 is 1 μm or less, and if it is in the above range, the conductor 14 having the above average diameter can be obtained.

The average diameter of the pores 13 is taken by a scanning electron microscope from directly above the surface of the insulating film 12 at a magnification of 100 to 10000 times to obtain a photographed image. At least 20 pores connected in a ring shape around the photographed image were extracted, the diameters thereof were measured and set as opening diameters, and the average value of the opening diameters was calculated as the average diameter of the pores.

The magnification of the above range can be appropriately selected to obtain a photographed image in which 20 or more pores can be extracted. And, the opening diameter measures the maximum value of the distance between the ends of the fine pore portions. That is, since the shape of the opening of the fine pores is not limited to a substantially circular shape, when the shape of the opening is a non-circular shape, the maximum value of the distance between the ends of the fine pore portion is defined as the opening diameter. Therefore, for example, in the case of a pore having a shape in which 2 or more pores are integrated, the maximum value of the distance between the ends of the pore portion is regarded as 1 pore, and the opening diameter is defined as the maximum value.

[ conductor ]

As described above, the plurality of conductors 14 are provided in the anodized film in a state of being electrically insulated from each other.

The plurality of conductors 14 have conductivity. The conductor is made of a conductive material. The conductive material is not particularly limited, and examples thereof include metals. Specific examples of the metal include gold (Au), silver (Ag), copper (Cu), aluminum (Al), magnesium (Mg), nickel (Ni), and the like. From the viewpoint of conductivity, copper, gold, aluminum, and nickel are preferable, copper and gold are more preferable, and copper is most preferable. Among metals, copper is a base metal, but may be a base metal. Although base metals are easily oxidized in the air, in the method for producing a metal-filled microstructure, a metal-filled microstructure having good conductivity can be obtained even when a conductor is formed of a base metal.

In addition to metals, oxide conductive substances can be cited. As the oxide conductive material, for example, indium-doped tin oxide (ITO) or the like is exemplified. However, the metal is preferably made of a metal because it is more ductile than an oxide conductor and easily deformed, and is easily deformed even by compression at the time of bonding.

The conductor may be made of a conductive resin containing nanoparticles of Cu, ag, or the like, for example.

The height H of the conductor 14 in the thickness direction Dt is preferably 10 to 300 μm, and more preferably 20 to 30 μm.

< shape of conductor >

The plurality of conductors preferably have a cross-sectional area of 20 μm in a cross-section perpendicular to the longitudinal direction of the conductors, i.e., the thickness direction Dt of the insulating film 12 ² The following conductors. The cross section area is 20 mu m ² The conductor below is about 3.99 μm or less in diameter d.

The average diameter d of the conductor 14 is more preferably 1 μm or less, still more preferably 5 to 500nm, still more preferably 20 to 400nm, still more preferably 40 to 200nm, and most preferably 50 to 100nm.

The density of the conductor 14 is preferably 2 ten thousand/mm ² More preferably 200 ten thousand/mm or more ² More preferably 1000 ten thousand/mm or more ² More than 5000 ten thousand/mm is particularly preferable ² More than, most preferably 1 hundred million/mm ² The above.

The pitch p between adjacent conductors 14 is preferably 20nm to 500nm, particularly preferably 40nm to 200nm, and further preferably 50nm to 140nm.

The average diameter of the conductor is obtained by taking an image of the surface of the anodic oxide film at a magnification of 100 to 10000 times from directly above using a scanning electron microscope. At least 20 conductors connected in a ring shape around the conductor are extracted from the photographed image, the diameters of the conductors are measured and set as opening diameters, and the average value of the opening diameters is calculated as the average diameter of the conductors.

Further, the magnification in the above range can be appropriately selected to obtain a photographic image from which 20 or more conductors can be extracted. And, the opening diameter is measured as the maximum value of the distance between the ends of the conductor portions. That is, since the shape of the opening of the conductor is not limited to a substantially circular shape, when the shape of the opening is non-circular, the maximum value of the distance between the ends of the conductor portion is defined as the opening diameter. Therefore, for example, in the case where 2 or more conductors are integrated conductors, the conductors are regarded as 1 conductor, and the maximum value of the distance between the ends of the conductor portion is set as the opening diameter.

< protruding part >

The protrusion is a part of the conductor and has a columnar shape. The protruding portion is preferably cylindrical because it can increase the contact area with the joining target.

The average length of the protrusions 14a and the average length of the protrusions 14b are preferably 30nm to 500nm, and the upper limit is preferably 100nm or less.

The average protrusion length of the protrusion 14a and the average length of the protrusion 14b are average values measured by acquiring sectional images of the protrusions by using a field emission type scanning electron microscope as described above and measuring the heights of the protrusions at 10 points, respectively, based on the sectional images.

[ resin layer ]

As described above, the resin layer is provided on at least one of the front surface and the back surface of the anodized film, for example, the protruding portion of the buried conductor. That is, the resin layer covers the end of the conductor protruding from the anodized film and protects the protruding portion.

In order to exhibit the above function, the resin layer is preferably a resin layer which exhibits fluidity at a temperature range of 50 to 200 ℃ and is cured at 200 ℃ or higher, for example. The resin layer will be described in detail later.

The average protruding length of the conductor 14 is preferably smaller than the average thickness of the resin layer 16. When both the average protruding length of the protruding portion 14a and the average length of the protruding portion 14b of the conductor 14 are smaller than the average thickness of the resin layer 16, both the protruding

portions

14a,14b are embedded in the resin layer portion 20a of the resin layer 16, and the conductor 14 is protected by the resin layer 16.

The average thickness of the resin layer 16 is an average distance from the front surface 12a of the insulating film 12 or an average distance from the back surface 12b of the insulating film 12. The average thickness of the resin layer 16 is an average value of 10-point measurement values obtained by cutting the resin layer in the thickness direction Dt of the metal-filled microstructure 10 and observing the cut cross section using a field emission scanning electron microscope (FE-SEM), and measuring the distance from the surface 12a of the insulating film 12 at the position corresponding to the resin layer 10. Then, the distance from the back surface 12b of the insulating film 12 was measured at the position corresponding to the resin layer 10, and the average value of the measured values of 10 points was taken.

The average thickness of the resin layer is preferably 200 to 1000nm, more preferably 400 to 600nm. When the average thickness of the resin layer is 200 to 1000nm, the effect of protecting the protruding portion of the conductor 14 can be sufficiently exhibited.

The size of each portion of the metal-filled microstructure 10 is an average value obtained by cutting the metal-filled microstructure 10 in the thickness direction Dt, observing the cross section of the cut cross section using a field emission scanning electron microscope (FE-SEM), and measuring 10 points at positions corresponding to each dimension, unless otherwise specified.

[ laminated device ]

Fig. 14 is a schematic diagram showing an example of a stacked device using a metal-filled microstructure according to an embodiment of the present invention. In addition, the laminated device 40 shown in fig. 14 uses the above-described metal-filled microstructure 10 (refer to fig. 8 and 11) as an anisotropic conductive member 45 exhibiting anisotropic conductivity.

The stacked device 40 shown in fig. 14 is a device in which, for example, a semiconductor element 42, an anisotropic conductive member 45, and a semiconductor element 44 are bonded and electrically connected in the stacking direction Ds in this order. The anisotropic conductive member 45 is formed by arranging the conductor 14 (see fig. 8 and 11) of the metal-filled microstructure 10 (see fig. 8 and 11) in parallel to the stacking direction Ds, and the stacked device 40 has conductivity in the stacking direction Ds.

The stacked device 40 is a system in which 1 semiconductor element 44 is bonded to 1 semiconductor element 42, but is not limited to this. The 3 semiconductor elements may be bonded to each other through the anisotropic conductive member 45. In this case, the stacked device is constituted by 3 semiconductor elements and 2 anisotropic conductive members 45.

The stacked device 40 is not limited to having a semiconductor element, and may be a substrate having an electrode. The substrate having the electrode is, for example, a wiring substrate, an interposer, or the like.

The form of the stacked device is not particularly limited, and examples thereof include SoC (System on a Chip), siP (System in Package), poP (Package on Package), piP (Package in Package), CSP (Chip Scale Package), TSV (Through Silicon Via), and the like.

The stacked device 40 may have a semiconductor element functioning as a photosensor. For example, the semiconductor element and the sensor chip (not shown) are stacked in the stacking direction Ds. A lens may be provided in the sensor chip.

In this case, the semiconductor element is an element in which a logic circuit is formed, and the structure thereof is not particularly limited as long as the semiconductor element can process a signal obtained by the sensor chip.

The sensor chip has a photosensor that detects light. The photosensor is not particularly limited as long as it can detect light, and for example, a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor is used.

The structure of the lens is not particularly limited as long as the lens can collect light to the sensor chip, and a lens called a microlens, for example, may be used.

As the

semiconductor elements

42, 44, and 46, elements having an element region (not shown) can be used. The element region is as described later. In the element region, an element constituting circuit and the like are formed, and in the semiconductor element, for example, a rewiring layer (not shown) is provided.

In the stacked device, for example, a combination of a semiconductor element having a logic circuit and a semiconductor element having a memory circuit can be used. All the semiconductor elements may be provided with a memory circuit or may be provided with a logic circuit. The combination of the semiconductor elements in the stacked device 40 may be a combination of a sensor, an actuator, an antenna, and the like, and a memory circuit and a logic circuit, and is appropriately determined according to the use and the like of the stacked device 40.

[ joining target of structures ]

The object to be bonded of the structure is exemplified by the semiconductor element described above, and includes, for example, an electrode or an element region. Examples of the element having an electrode include a semiconductor element which performs a specific function as a single element, and a plurality of elements which perform a specific function by being grouped together. Further, the present invention also includes a component that transmits only an electric signal, such as a wiring component, and a printed wiring board and the like are also included in a component having an electrode.

The element region is a region where various element configuration circuits and the like for functioning as electronic elements are formed. The element region includes, for example, a region where a memory circuit such as a flash memory or the like, a logic circuit such as a microprocessor or an FPGA (field-programmable gate array) or the like is formed, and a region where a communication module such as a wireless tag or the like and a wiring are formed. In the element region, other than this, a Micro Electro Mechanical Systems (MEMS) may be formed. Examples of the MEMS include a sensor, an actuator, and an antenna. The sensor includes various sensors such as an acceleration sensor, an acoustic sensor, and an optical sensor.

As described above, an element constituting circuit and the like are formed in the element region, and electrodes (not shown) are provided for electrically connecting the semiconductor chip to the outside. The element region has an electrode region in which an electrode is formed. The electrode in the element region is, for example, a Cu pillar. Electrode area refers to the area that includes substantially all of the electrodes formed. However, when the electrodes are dispersedly disposed, the region where each electrode is disposed is also referred to as an electrode region.

The structure may be in the form of a single chip such as a semiconductor chip, a semiconductor wafer, or a wiring layer.

The structure is bonded to the object to be bonded, but the object to be bonded is not particularly limited to the semiconductor element described above, and for example, a semiconductor element in a wafer state, a semiconductor element in a chip state, a printed wiring board, a heat sink, and the like are the objects to be bonded.

[ semiconductor element ]

<xnotran> 42 44 , , LSI (Large Scale Integration: ) (, ASIC (Application Specific Integrated Circuit: ), FPGA (Field Programmable Gate Array: ), ASSP (Application Specific Standard Product: ) ), (, CPU (Central Processing Unit: ), GPU (Graphics Processing Unit: ) ), (, DRAM (Dynamic Random Access Memory: ), HMC (Hybrid Memory Cube: ), MRAM (Magnetic RAM: ) PCM (Phase-Change Memory: ), reRAM (Resistive RAM: ), feRAM (Ferroelectric RAM: ), (NAND (Not AND) ) ), LED (Light Emitting Diode: ), (, , , , LCD , ), /, IC (Integrated Circuit: ), (, DC (Direct Current: ) -DC (Direct Current: ) , (IGBT) ), MEMS (Micro Electro Mechanical Systems: ), (, , </xnotran> Pressure sensors, vibrators, gyro sensors, etc.), radios (for example, GPS (Global Positioning System), FM (Frequency Modulation), NFC (near field communication), RFEM (RF Expansion Module), MMIC (Monolithic Microwave Integrated Circuit), WLAN (wireless local area network), etc.), discrete elements, BSI (Back Side Illumination: back surface illuminance), CIS (Contact Image Sensor: contact image sensor), camera module, CMOS (Complementary Metal Oxide Semiconductor: complementary metal oxide semiconductor), passive devices, SAW (Surface Acoustic Wave: surface acoustic wave) filter, RF (Radio Frequency: radio Frequency) filter, RFIPD (Radio Frequency Integrated Passive Devices: radio frequency integrated passive device), BB (Broadband: broadband), etc.

The semiconductor element is, for example, 1 complete element, and a specific function such as a circuit or a sensor is exerted by the semiconductor element alone. The semiconductor element may have the function of an interposer. Further, for example, a plurality of devices such as a logic chip having a logic circuit and a memory chip may be stacked on a device having a function of an interposer. In this case, bonding can be performed even if the electrode size differs for each device.

The multilayer device is not limited to the 1-pair-multiple mode in which a plurality of semiconductor elements are bonded to 1 semiconductor element, and may be a multiple-pair-multiple mode in which a plurality of semiconductor elements are bonded to a plurality of semiconductor elements.

The present invention is basically configured as described above. Although the method for producing a metal-filled microstructure of the present invention has been described in detail above, the present invention is not limited to the above embodiment, and various improvements and modifications can be made without departing from the scope of the present invention.

Examples

The features of the present invention will be described in more detail below with reference to examples. The materials, reagents, amounts of substances, the operation and the like shown in the following examples can be appropriately modified without departing from the spirit of the present invention. Accordingly, the scope of the present invention is not limited to the following examples.

In this example, the metal-filled microstructures of examples 1 to 12 and the metal-filled microstructure of comparative example 1 were produced. The metal-filled microstructures of examples 1 to 12 and comparative example 1 were evaluated for conductivity. The evaluation results of the conductivity are shown in table 1 below. The evaluation of the conductivity will be described below.

< conductivity >

A TEG chip (daisy chain pattern) and an interposer manufactured by WALTS co.

After the positioning was adjusted, the prepared metal-filled microstructures were stacked on the Cu pillar side of the interposer disposed on the lower side, and bonded by heat and pressure bonding at a temperature of 250 ℃ and 6MPa for 1 minute using a room temperature bonding apparatus (model No. WP-100, manufactured by PMT Corporation). The resistance between the chip wires was measured for the bonded samples.

Examples 1 to 12 and comparative example 1 will be described below.

(example 1)

The metal-filled microstructure of example 1 will be described.

[ Metal-filled microstructure ]

< production of aluminum substrate >

The use of a catalyst containing Si:0.06 mass%, fe:0.30 mass%, cu:0.005 mass%, mn:0.001 mass%, mg:0.001 mass%, zn:0.001 mass%, ti:0.03 mass% and the balance of Al and inevitable impurities, and an ingot having a thickness of 500mm and a width of 1200mm is produced by a DC (Direct Chill) casting method on the basis of the molten metal treatment and filtration.

Next, after the surface was cut with a surface cutter at an average thickness of 10mm, the surface was soaked at 550 ℃ for about 5 hours, and when the temperature was lowered to 400 ℃, a rolled sheet having a thickness of 2.7mm was produced using a hot rolling mill.

Further, after heat treatment at 500 ℃ using a continuous annealing machine, the aluminum substrate was finished to a thickness of 1.0mm by cold rolling to obtain an aluminum substrate of JIS (Japanese Industrial Standards) 1050 material.

After the aluminum substrate had a width of 1030mm, the following treatments were performed.

< electropolishing treatment >

The above aluminum substrate was subjected to an electrolytic polishing treatment using an electrolytic polishing liquid having the following composition under conditions of a voltage of 25V, a liquid temperature of 65 ℃ and a liquid flow rate of 3.0 m/min.

The cathode was a carbon electrode, and GP0110 to 30R (manufactured by TAKASAGO LTD.) was used as a power source. Also, the flow rate of the electrolyte was measured using a vortex type flow monitor FLM22-10PCW (manufactured by AS ONE corporation).

(electrolytic polishing composition)

85% by mass of phosphoric acid (Wako Pure Chemical, ltd. Manufactured reagent) 660mL

160mL of pure water

Sulfuric acid 150mL

Ethylene glycol 30mL

< anodic Oxidation treatment step >

Next, the aluminum substrate after the electrolytic polishing treatment was anodized by a self-ordering method in accordance with the procedure described in Japanese patent application laid-open No. 2007-204802.

The aluminum substrate after the electrolytic polishing treatment was subjected to a pre-anodizing treatment for 5 hours using 0.50mol/L oxalic acid electrolyte at a voltage of 40V, a liquid temperature of 16 ℃ and a liquid flow rate of 3.0 m/min.

Then, the aluminum substrate after the pre-anodic oxidation treatment was subjected to a stripping treatment by immersing the substrate in a mixed aqueous solution (liquid temperature: 50 ℃ C.) of 0.2mol/L chromic anhydride and 0.6mol/L phosphoric acid for 12 hours.

Then, a re-anodization treatment was performed for 3 hours and 45 minutes using an electrolytic solution of oxalic acid at a concentration of 0.50mol/L under conditions of a voltage of 40V, a liquid temperature of 16 ℃ and a liquid flow rate of 3.0m/min, thereby obtaining an anodized film having a film thickness of 30 μm.

In both the pre-anodization and the re-anodization, the cathodes were stainless steel electrodes, and GP0110 to 30R (manufactured by TAKASAGO LTD.) was used as the power source. The cooling device used was NeoCool BD36 (manufactured by Yamato Scientific Co., ltd.), and the stirring and heating device used was a twin stirrer PS-100 (manufactured by Eyelatokyo RIKAKIKAI CO, LTD.). Further, the flow rate of the electrolyte was measured using a swirl flow monitor FLM22-10PCW (manufactured by AS ONE corporation).

< Barrier layer removal step >

Next, after the anodizing treatment step, an etching treatment of immersing the anodized film in an alkaline aqueous solution obtained by dissolving zinc oxide in an aqueous sodium hydroxide solution (50 g/1) at 2000ppm for 150 seconds at 30 ℃ was performed to remove the barrier layer located at the bottom of the micropores (pores) of the anodized film and simultaneously deposit zinc on the exposed surface of the aluminum substrate.

The average thickness of the anodized film after the barrier layer removal step was 30 μm.

< Metal filling Process >

Next, an electrolytic plating treatment was performed with the aluminum substrate as a cathode and platinum as a cathode.

Specifically, a metal-filled microstructure having pores filled with nickel was produced by performing constant current electrolysis using a copper plating solution having the following composition. Here, a plating apparatus manufactured by Yamamoto-MS co., ltd. and a power supply (HZ-3000) manufactured by HOKUTO DENKO CORPORATION were used for constant current electrolysis, and after cyclic voltammetry was performed in a plating solution to confirm a deposition potential, treatments were performed under the following conditions.

(composition and conditions of copper plating solution)

100g/L copper sulfate

50g/L sulfuric acid

Hydrochloric acid 15g/L

Temperature 25 deg.C

Current density 10A/dm ²

The surface of the anodic oxide film after the micropores were filled with the metal was observed by FE-SEM, and whether or not the sealing by the metal was present in 1000 micropores was observed, and the sealing ratio (the number of sealed micropores/1000) was calculated to be 98%.

Then, the anodized film after filling the metal in the micropores was cut in the thickness direction by FIB, and a surface photograph (magnification: 50000 times) was taken of the cross section thereof by FE-SEM, and it was found that the inside of the micropores was completely filled with the metal.

< surface Metal protrusion step >

The structure after the metal filling step was immersed in an aqueous sodium hydroxide solution (concentration: 5 mass%, liquid temperature: 20 ℃) for an immersion time adjusted so that the height of the protruding portion became 400nm and the surface of the anodized film of aluminum was selectively dissolved, thereby producing a structure in which copper as a filler metal protruded.

< resin layer Forming step >

A heat-peelable resin base with an adhesive layer (Riva Alpha 3195MS, manufactured by NITTO DENKO corporation) was adhered to the surface of the side not provided with the aluminum substrate.

< substrate removing step >

Next, the aluminum substrate was immersed in a mixed solution of copper chloride and hydrochloric acid and dissolved and removed, thereby producing a metal-filled microstructure having an average thickness of 30 μm.

The diameter of the conductive paths in the metal-filled microstructure was 60nm, the pitch between the conductive paths was 100nm, and the density of the conductive paths was 5770 ten thousand/mm ² 。

< backside Metal protrusion step >

< heating step and removing step >

A structural body is disposed in the container. Then, the user can use the device to perform the operation,the atmosphere in the vessel was defined such that, assuming that the total pressure was 100%, the partial pressure of each gas was 80% nitrogen and 20% oxygen, and the total pressure was 4.0 × 10 ^-2 Pa atmosphere. After heating the resin layer at 120 ℃ for 2 minutes using a heater, the resin layer was peeled. The pressure in the vessel was reduced by a vacuum pump to adjust the total pressure.

Further, the mixed gas is injected so that the gas ratio is desirably the same as the total pressure. For example, the gas ratio is set to N ₂ ：O ₂ =80:20 and a total pressure of 4.0Pa, N is carried out ₂ After purging (nitrogen purging), the pressure was reduced by a vacuum pump and adjusted to 3.2Pa, and then O was injected ₂ The total pressure of the gas was set to 4.0Pa.

The resin layer is peeled off in an atmospheric atmosphere.

(example 2)

In example 2, the atmosphere in the heating step was prepared in the same manner as in example 1 except that the partial pressure of each gas was 80% nitrogen and 20% oxygen, and the total pressure was 4.0Pa, assuming that the total pressure was 100%.

(example 3)

In example 3, the atmosphere in the heating step was defined as 100% in total pressure, except that the partial pressure of each gas was 80% nitrogen and 20% oxygen, and the total pressure was 1.0 × 10 ⁴ Pa was produced in the same manner as in example 1.

(example 4)

In example 4, the atmosphere in the heating step was defined as 100% in total pressure, except that the partial pressure of each gas was 99.8% nitrogen and 0.2% oxygen, and the total pressure was 1.0 × 10 ⁶ Except Pa, the production was performed in the same manner as in example 1.

(example 5)

In example 5, the atmosphere in the heating step was changed to 100% in total pressure except that the partial pressure of each gas was argon 99.8%, oxygen 0.2%, and the total pressure was 1.0 × 10 ⁶ Pa was produced in the same manner as in example 1.

(example 6)

In example 6, the atmosphere in the heating step was defined as 100% of total pressure, except that the partial pressure of each gas was 99.8% of hydrogen and 0.2% of oxygen, and the total pressure was 1.0 × 10 ⁶ Pa was produced in the same manner as in example 1.

(example 7)

In example 7, the production was performed in the same manner as in example 1 except that the partial pressure of each gas was 99.998% of nitrogen, 0.002% of oxygen, and the total pressure was 4.0Pa, assuming that the atmosphere in the heating step was 100% of the total pressure.

(example 8)

In example 8, the atmosphere of the heating step was prepared in the same manner as in example 1 except that the partial pressure of each gas was argon 99.998%, oxygen 0.002% and the total pressure was 4.0Pa, assuming that the total pressure was 100%.

(example 9)

In example 9, the production was performed in the same manner as in example 1 except that the partial pressure of each gas was 99.998% of hydrogen, 0.002% of oxygen, and the total pressure was 4.0Pa, assuming that the atmosphere in the heating step was 100% of the total pressure.

(example 10)

In example 10, the heat-peelable adhesive layer-equipped resin base material was changed to Riva Alpha (registered trademark) 3195VS (manufactured by NITTO DENKO corporation). The atmosphere in the heating step was defined as a total pressure of 100%, the partial pressure of each gas was defined as 80% nitrogen and 20% oxygen, and the total pressure was defined as 1.0X 10 ⁴ Pa. The production was performed in the same manner as in example 1, except that the resin layer was heated at a temperature of 170 ℃ for 2 minutes and the resin layer was peeled.

(example 11)

In example 11, the atmosphere of the heating step was prepared in the same manner as in example 10 except that the partial pressure of each gas was 99.998% nitrogen, 0.002% oxygen and the total pressure was 4.0Pa, assuming that the total pressure was 100%.

(example 12)

In example 12, the same procedure as in example 3 was repeated, except that the thermally peelable adhesive layer-equipped resin base material was changed to Somatac TE PS-2021TE (manufactured by SOMAR corporation) in the resin layer forming step.

Comparative example 1

In comparative example 1, except that the total pressure of the atmosphere in the heating step was 1.0X 10 ⁶ Except for Pa, the production was performed in the same manner as in example 12.

[ Table 1]

	Atmosphere (partial pressure ratio of gas)	Total pressure (Pa)	Partial pressure of oxygen (Pa)	Heating temperature (. Degree.C.)	Conductivity (omega)
						Example 1	80 percent of nitrogen and 20 percent of oxygen	4.0×10 ^-2	8.0×10 ^-3	120	170
Example 2	80 percent of nitrogen and 20 percent of oxygen	4.0	8.0×10 ^-1	120	200
						Example 3	80 percent of nitrogen and 20 percent of oxygen	1.0×10 ⁴	2.0×10 ³	120	250
Example 4	99.8 percent of nitrogen and 0.2 percent of oxygen	1.0×10 ⁶	2.0×10 ³	120	250
						Example 5	99.8 percent of argon and 0.2 percent of oxygen	1.0×10 ⁶	2.0×10 ³	120	250
Example 6	99.8 percent of hydrogen and 0.2 percent of oxygen	1.0×10 ⁶	2.0×10 ³	120	230
						Example 7	99.998 percent of nitrogen0.002% of oxygen	4.0	8.0×10 ^-3	120	170
Example 8	99.998 percent of argon and 0.002 percent of oxygen	4.0	8.0×10 ^-3	120	170
						Example 9	99.998 percent of hydrogen and 0.002 percent of oxygen	4.0	8.0×10 ^-3	120	150
Example 10	80 percent of nitrogen and 20 percent of oxygen	1.0×10 ⁴	2.0×10 ³	170	280
						Example 11	99.998 percent of nitrogen and 0.002 percent of oxygen	4.0	8.0×10 ^-3	170	200
Example 12	80 percent of nitrogen and 20 percent of oxygen	1.0×10 ⁴	2.0×10 ³	120	250
						Comparative example 1	80 percent of nitrogen and 20 percent of oxygen	1.0×10 ⁶	2.0×10 ⁵	120	400

As shown in table 1, examples 1 to 12 have lower resistance and better conductivity than comparative example 1.

In comparative example 1, the oxygen partial pressure exceeded 10000Pa in the atmosphere of the heating step, and the resistance increased.

In examples 1, 2, 7 to 9, and 11, the oxygen partial pressure was 1.0Pa or less, and the resistance was smaller and the conductivity was better.

In examples 1 to 3, the lower the total pressure, the lower the resistance and the good conductivity.

In examples 3 and 10 and examples 7 and 11, the lower the heating temperature, the lower the resistance and the good conductivity.

Description of the symbols

10-metal filled microstructure, 12-insulating film, 12 a-surface, 12 b-back surface, 13-fine pore, 14-conductor, 14 a-protrusion, 14 b-protrusion, 15-anodized film, 16-resin layer, 18-structure, 21-core, 30-aluminum substrate, 30 a-surface, 31-barrier layer, 32 c-bottom, 32 d-surface, 35-metal, 35 a-metal layer, 35 b-metal, 40-layered device, 42-semiconductor element, 44-semiconductor element, 45-anisotropic conductive member, ds-layered direction, dt-thickness direction, H-height, d-average diameter, ht-thickness, p-center pitch.

Claims

1. A method for manufacturing a metal-filled microstructure, comprising:

a preparation step of preparing a structure having an insulating film and a plurality of conductors provided in a state of penetrating the insulating film in a thickness direction and being electrically insulated from each other, the conductors protruding from at least one surface of the insulating film in the thickness direction, the structure having a resin layer covering the surface of the insulating film from which the conductors protrude;

a heating step of heating at least the resin layer in an atmosphere having an oxygen partial pressure of 10000Pa or less; and

a removing step of removing the resin layer heated by the heating step from the insulating film,

the resin layer contains a heat-peelable adhesive.

2. The method for producing a metal-filled microstructure according to claim 1,

in the heating step, the oxygen partial pressure of the atmosphere is 1.0Pa or less.

3. The method for producing a metal-filled microstructure according to claim 1 or 2,

in the heating step, the partial pressure of the inert gas in the atmosphere is 85% or more of the total pressure of the atmosphere.

4. The method of producing a metal-filled microstructure according to any one of claims 1 to 3,

in the heating step, the partial pressure of the reducing gas in the atmosphere is 85% or more of the total pressure of the atmosphere.

5. The method of producing a metal-filled microstructure according to any one of claims 1 to 4,

in the heating step, the total pressure of the atmosphere is 5.0Pa or less.

6. The method of producing a metal-filled microstructure according to any one of claims 1 to 5,

the conductor comprises a base metal.

7. The method of producing a metal-filled microstructure according to any one of claims 1 to 5,

the plurality of conductors have a cross-sectional area of 20 μm in a cross-section perpendicular to a longitudinal direction of the conductors ² The following conductors.

8. The method of producing a metal-filled microstructure according to any one of claims 1 to 7,

the resin layer in the heating step has an arrival temperature of 150 ℃ or lower.

9. The method of producing a metal-filled microstructure according to any one of claims 1 to 8,

the conductors protrude from both surfaces of the insulating film in the thickness direction,

the resin layers are respectively provided on both sides of the insulating film in the thickness direction.

10. The method of producing a metal-filled microstructure according to any one of claims 1 to 9,

the insulating film is an anodic oxide film.