JP2002036424A - Laminated foil, wiring board using laminated foil and method for manufacturing laminated foil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a laminated foil by which a laminated foil with high adhesive strength is obtained by using a method for appropriately treating the surface of a metallic foil arranged on both sides of an intermediate layer. SOLUTION: In the laminated foil consisting of the intermediate layer, formed of a Group IVa metal or an alloy composed mainly of the Group IVa metal, which is a dry film forming layer, an oxygen concentration layer having 50 atomic % or more oxygen content formed from an interface between the intermediate layer and the metallic foil arranged on both sides of the intermediate layer to the Group IVa metal side, is 0.1 μm or less thick.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a laminated foil, a wiring board using the same, and a method for producing the laminated foil.

[0002]

2. Description of the Related Art Laminated materials have a wide variety of applications from structural materials to functional materials. Above all, in the field of semiconductor packages related to the digitalization of multimedia devices and the rapid increase of portable devices in recent years, many laminated materials have been used. Focusing on the difference in the etching characteristics of the materials, it is easy to form a specific etching pattern only on a specific metal material or to remove only a specific metal material by etching.

As an example of this, as a method for forming a wiring pattern on a semiconductor package, a technique called a transfer method using a laminated foil is disclosed in Japanese Patent Application Laid-Open No. Hei 5-998816. As a technique called this transfer method, FIGS. 4 (a) to 4 (f)
As shown in the figure, after forming an Ni plating layer as an intermediate layer (1) using an electrolytic copper foil as a cathode as a carrier material (6), laminating a dry film resist (8), exposing, developing, A resist pattern is formed, copper sulfate plating is applied as a wiring forming material (7), the resist is peeled off using a potassium hydroxide solution, and a copper wiring pattern is formed on a three-layer transfer method foil material (10) Get. Next, the transfer method foil material (10) is set in a mold, the copper wiring pattern side is transferred to the semiconductor sealing epoxy resin (9), and selective etching is performed on each of the carrier material and the intermediate layer. Only the transferred copper wiring pattern can be left.

In this transfer method, when a wiring forming material having a thickness of 18 μm or less is used, there is a problem in handling properties. Therefore, a carrier material is used to impart rigidity, and the intermediate layer is used as a barrier layer as a carrier layer. Used to prevent the etching solution from reaching the wiring forming material when removing the material by etching, and conversely, when the wiring forming material is subjected to wiring patterning with the etching solution, the etching solution is not allowed to reach the carrier material. Used for Therefore, the intermediate layer needs to be a metal having different etching conditions from the carrier material and the wiring forming material. By using the above-described transfer method, handling is easy, and after removing only the carrier material by selective etching from the copper foil of the wiring transferred to the semiconductor sealing epoxy resin, only the intermediate layer is removed by selective etching. It is excellent as a method that hardly causes etching spots.

[0005]

However, the present inventors have examined that when Ni is used as the intermediate layer,
Since Ni is completely dissolved in metal such as Cu used as the wiring forming material and carrier material described above, for example, a layer in which Cu and Ni are mixed at the bonding interface due to the heat history of the process and the like. For example, during the selective etching of Ni, there arises a problem that an undissolved Ni layer in which a large amount of Cu is dissolved or an etching time is required to completely remove the Ni layer.

[0006] In addition, JP-A-8-293510 discloses that aluminum, copper, and titanium can be formed by a vacuum deposition method in addition to the method of forming a barrier layer serving as an intermediate layer by a plating method as described above. Have been. However, in the manufacturing method disclosed in JP-A-8-293510, aluminum, copper, and titanium are stacked on a carrier metal foil to form a barrier layer, and Cu is further stacked by plating. In the case where active metals such as titanium are laminated, even if a vapor deposition layer is formed in a vacuum, a two-layer laminated foil is exposed from the vacuum to the atmosphere, and a thin oxide layer is formed on the titanium surface. However, the third metal foil has a remarkably inferior adhesive strength with the second metal layer, making it difficult to bond and form the metal foil. There was also a disadvantage that it had to be done.

US Pat. No. 4,011,982 discloses a method in which an intermediate layer is formed by a method such as a vacuum evaporation method and two metal strips are surface-bonded. Further, it is shown that titanium can be used as the intermediate layer. However, the present inventors have examined that titanium is very easily oxidized,
It was found that when vapor deposition was performed when the surface of the metal strip serving as the substrate was oxidized, titanium took in oxygen and became significantly embrittled. An object of the present invention is to provide a laminated foil capable of obtaining a laminated foil having high adhesive strength by appropriately performing a surface treatment method of a metal foil disposed on both surfaces of the intermediate layer, and a wiring board using the same. An object of the present invention is to provide a method for producing a laminated foil.

[0008]

Means for Solving the Problems In the art utilizing selective etching, the present inventor has described a metal forming an intermediate layer and a metal sandwiching the metal forming the intermediate layer.
As a result of diligent studies on the optimal combination of metal laminated foils, we found that by forming an intermediate layer consisting of a Group IVa metal or an alloy containing a Group IVa metal as a main component, a laminated foil with excellent selective etching properties was obtained. did. However, group IVa metals or alloys composed mainly of group IVa metals are very active, and oxygen-enriched layers are a problem in joining.As a result of studying various joining techniques, the formation of oxygen-enriched layers The present inventor has found a technique capable of suppressing this and has reached the present invention.

That is, the present invention provides a laminated foil having an intermediate layer made of a Group IVa metal or an alloy containing a Group IVa metal as a main component, wherein the intermediate layer is a dry film-forming layer, and the intermediate layer and the intermediate layer From the interface with the metal foil disposed on both sides of the above, the oxygen-enriched layer having an oxygen content of 50 atomic% or more formed on the side of the IVa group metal or the alloy containing the IVa group metal as a main component. It is a laminated foil having a thickness of 0.1 μm or less. Preferably, at the interface between the intermediate layer and the metal foil disposed on at least one surface side of the intermediate layer, an IVa group metal or an alloy containing a IVa group metal as a main component, and a metal contained in the metal foil. Is more preferably a solid foil with a group IVa metal or an alloy containing a group IVa metal as a main component on at least one surface side of the intermediate layer. This is a laminated foil on which a metal foil having an atomic percent or less is arranged.

Still more preferably, an interface between the intermediate layer and a metal foil disposed on at least one surface of the intermediate layer includes a group IVa metal or an alloy containing a group IVa metal as a main component, Is a laminated foil in which an intermetallic compound layer containing a metal as a main component is formed, and the thickness of the intermetallic compound layer is 1 μm or less, more preferably, IVa
A laminated foil in which the group metal is Ti. Still more preferably,
The metal foil disposed on both sides of the intermediate layer is a laminated foil that is a metal foil containing Cu as a main component, and the thickness of the metal foil disposed on at least one side of the intermediate layer is 50 μm or less. In addition, the laminated foil has a total thickness of 150 μm or less. Further, the present invention is a wiring board formed using the above-mentioned laminated foil.

[0011] Further, the production method of the present invention is characterized in that the intermediate layer made of a Group IVa metal or an alloy containing a Group IVa metal as a main component is a dry film-forming layer, and the metal foil is disposed on at least one surface of the intermediate layer. On the surface of the adhesive surface side, the IVa group metal or an alloy containing a IVa group metal as a main component is adhered and formed by a dry film forming method, and a method for producing a laminated foil to be roll-pressed,
This is a method for producing a laminated foil, in which a surface cleaning treatment is performed on a surface of a metal foil disposed on both surfaces of the intermediate layer on a bonding surface side before dry film formation. Preferably, the method is a method for producing a laminated foil in which the roll-pressed laminated foil is heat-treated at a temperature of 700 ° C. or less.

More preferably, the metal foil disposed on at least one surface of the intermediate layer has a solid solubility with the Group IVa metal of 3 atomic% or less with respect to each other. More preferred is a method for producing a laminated foil in which the group IVa metal is Ti. Still more preferably, a method for producing a laminated foil in which the metal foil disposed on both surfaces of the intermediate layer is a metal foil containing Cu as a main component, and more preferably, on at least one surface of the intermediate layer. The thickness of the placed metal foil is 50
μm or less, and the total thickness of the laminated foil is 150 μm or less, and more preferably, the above-mentioned metal foil is unwound from an unwinding reel, roll-pressed, and wound up. This is a method for producing a laminated foil wound on a reel.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. An important feature of the present invention is that, as shown in FIG.
An oxygen-containing layer formed on the group IVa metal side from the interface between the intermediate layer (1) made of an alloy mainly composed of a group IV metal or a group IVa metal and the metal foil (2) disposed on both surfaces thereof The reason is that the thickness of the oxygen-enriched layer (3) having an amount of 50 atomic% or more is suppressed and bonding is performed. The greatest advantage of using this IVa group metal is that the IVa group metal has excellent chemical properties and high barrier properties against many etching solutions. growing. For example, when Ni as used in the above-described transfer method is used as the intermediate layer,
Alkaline etchant was used for Cu foil etchant, but if Ti, one of the IVa group metals, is used as the intermediate layer, Cu Iron will also be available. The advantage of increasing the degree of freedom in selecting an etching solution is that
A similar effect can be obtained with a metal containing a group a metal as a main component.

The advantages of using a group IVa metal are listed below. Since a group IVa metal is active and has high strength, a laminated foil having high bonding strength can be obtained. Moreover, the IVa group metal is rich in ductility and can be subjected to plastic working. However, as described above, since the IVa group metal is active, it easily absorbs oxygen and forms a tetravalent oxide film on the surface in air to stabilize. Here, the tetravalent oxide having an oxidation number refers to, for example, TiO ₂ , ZrO ₂ , and HfO ₂ . Due to such disadvantages, when bonding with a metal foil, if the oxygen content at the interface between the intermediate layer and the metal foil is high, ductility is significantly reduced and interface delamination is likely to occur. In particular, when an oxide is formed at the interface, the bonding strength is significantly reduced, so it is necessary to control the oxygen content at the interface between the intermediate layer and the metal foil to a specific amount, specifically, the intermediate layer If the thickness of the oxygen-enriched layer having an oxygen content exceeding 50 atomic% on the group IVa metal side exceeds 0.1 μm, interfacial delamination is particularly likely to occur. The content needs to be 50 atomic% or less.

The oxygen content on the side of the IVa group metal serving as the intermediate layer is determined by dry etching the laminated foil from the surface with a photoelectron spectrometer (also called ESCA or XPS) or an Auger spectrometer (also called AES). In the present invention, the interface is a position (depth) at which the main element constituting the metal foil disposed on both surfaces of the intermediate layer is 50 atomic%. By the way, when analyzing in the depth direction using this photoelectron spectroscopy analyzer, there is a drawback that it is not known how much the analyte is sputtered (dry-etched). Therefore, in general, adjustment is performed so that, for example, 1.5 nm is sputtered by sputtering for one minute using a standard sample made of SiO ₂ , and under these conditions, various unknown samples are also adjusted by sputtering for one minute. It is assumed that a thickness of 1.5 nm has been removed. In accordance with this, the present inventors also used a standard sample made of SiO ₂ , and 1.5 nm by sputtering for 1 minute.
The thickness (depth) of the sample was analyzed using a photoelectron spectroscopy analyzer adjusted so as to be dry-etched. The depth of the chemical layer was determined.

Further, as described above, care must be taken in manufacturing the laminated foil of the present invention. For example, in advance, a group IVa metal or an alloy containing it as a main component is formed on the surface of the metal foil sandwiching the intermediate layer, and ion etching is performed in a vacuum chamber to remove a surface oxygen-rich layer, Alternatively, vapor deposition in a vacuum chamber, ion plating, one of metal foils that have been subjected to a surface cleaning treatment of a Group IVa metal or an alloy containing the same as a main component by a dry film formation method in a vacuum such as sputtering, or It is preferable to adhere to both of them, and to join them together by continuous roll-pressing.

Here, the surface cleaning treatment means a physical method such as ion etching or a chemical method such as pickling.
It refers to a mechanical method such as sandblasting, and its main function is to remove an oxide layer and contaminants formed on the surface. Among these, in a mechanical method such as sand blasting, when the thickness of the metal foil is about several μm, and the material is low in hardness of the metal foil and easily plastically deformed,
Since there is a possibility that the metal foil is deformed during sandblasting, the blasting conditions should consider the thickness and material of the metal foil, and this method is preferably applied to a relatively thick metal foil. Further, for example, SiO ₂ used for sandblasting
Since the fragments of the particles and the residues of the metal foil to be blasted remain, it is necessary to perform a step of removing these fragments and the residues of the metal foil in a later step.

Further, the pickling cleaning can be sufficiently applied even if the thickness of the metal foil is as thin as about several μm, but residues such as corrosion products due to the pickling may remain. . Therefore, it is preferable to remove the residues by using pure water or an organic solvent after the pickling and washing to remove these residues. In a physical method such as ion etching, by providing an ion etching apparatus in a vacuum chamber,
In the vacuum chamber for dry film formation, the steps of cleaning, dry film formation and joining can be continuously performed. In this case, it goes without saying that productivity can be further improved by using a metal foil as the band material.

In the cleaning process described above, the metal foil after the cleaning process has to be once released to the atmosphere, except for the case where it can be manufactured in-line as described above. At this time, if it is exposed to the atmosphere for more than 4 hours, for example, a new oxide layer may be formed on the surface, and the effect of the corner cleaning process may be impaired. Therefore, the effect is maintained if the exposure time to the atmosphere is set to about 4 hours at the maximum.

Since the metal foil used in the present invention is bonded by roll pressing, it is preferable to select a metal foil having a smooth surface roughness at least on the bonding surface side. Therefore, there is an advantage that a laminated foil having higher adhesive strength can be obtained. Further, for example, when used as an application to be subjected to selective etching, such as the above-described composite foil for the transfer method, since the rolled foil has less variation in thickness, there is no problem that the etching time is locally different, and in particular, When both sides are rolled and roll pressed,
For applications provided for selective etching, first, the adjustment of the etching time is easy, second, the prevention of voids that cause deterioration of bonding strength at the bonding interface, and third, the plating step with low productivity can be omitted, Further, a fourth advantage is that the unwinding and rewinding from reel to reel is easy and contributes to an improvement in productivity, which is particularly desirable.

By the way, if heating is performed before the metal foil is pressed, the oxide on the surface of the metal foil is slightly removed, so that heating the metal foil is also an effective means. However, depending on the material of the metal foil to be pressed, there is a material for which heating of the metal foil is not necessarily effective, and specifically, Cu or a Cu alloy corresponds thereto. When heated at a temperature higher than 150 ° C, the Cu and Cu alloys are significantly reduced in rigidity, causing the metal foil to bend between the unwinding reel and the pressure roll, causing wrinkles during pressure bonding and causing defects. In particular, when using a metal foil of about several μm as a material such as a wiring board for forming fine wiring, excessive heating should be avoided, and even if heating is performed at a maximum of 150 ° C., preferably 100 ° C. Hereinafter, it is most preferable not to perform special heating.

The group IVa metal has a relatively high melting point, and hardly diffuses with the metal foil in the heat history at a low temperature, but forms an extremely thin diffusion layer and the bonding becomes strong.
Therefore, after the roll bonding, heat treatment is performed at a low temperature, for example, and a diffusion layer (4) is actively formed with the metal foil (2) on at least one side as shown in FIG. Is effective. What is low temperature here
700 ° C or lower, above which the diffusion morphology changes dramatically, a thick diffusion layer is formed, which may adversely affect the etching barrier properties described below, , The metal foil may be deteriorated. Therefore, the heat treatment is desirably 700 ° C. or less. Note that even if the diffusion layer is formed by the heat treatment, the thickness of the oxygen-enriched layer hardly changes, and depending on the heat treatment conditions,
For example, an oxygen-enriched layer may be included in the diffusion layer or have the same thickness.

Further, by joining together metal foils having low solid solubility to the intermediate layer made of Group IVa metal, almost no solid solution is formed between the intermediate layer and the metal foil. Therefore, the laminated foil of the present invention has no residual melt during selective etching. However, when a metal foil having a solid solubility of more than 3 atomic% with the group IVa metal is used, a solid solution is formed between the intermediate layer and the metal foil. When the selective etching is performed, the boundary is formed and the boundary becomes unclear, and there is an undissolved portion, the etching time is long to completely remove them, or the etching proceeds unevenly, and the barrier property of the intermediate layer is lost. Such a problem arises. Therefore, the metal foil disposed on at least one surface of the intermediate layer is preferably a metal foil having a solid solubility with the IVa group metal of 3 atomic% or less. Preferably, a metal foil having a solid solubility of 1 atomic% or less with the group IVa metal is preferably used. The solid solubility referred to in the present invention is a value at room temperature.

In addition, since the metal foils are combined with metal foils having almost no solid solubility as described above, even if the diffusion proceeds, a thin intermetallic compound layer is formed to further strengthen the bonding. Further, since this intermetallic compound layer is so thin that it does not pose a problem during selective etching, an intermetallic compound may be present between the intermediate layer and the metal foil. Here, when the thickness of the intermetallic compound layer exceeds 1 μm, the selective etching property is remarkably deteriorated, and the mechanical properties are adversely affected. In particular, problems such as undissolved residue occur at the time of removal. In addition,
With respect to these advantages, a similar effect can be obtained with a metal containing a Group IVa metal as a main component.

The group IVa metals referred to in the present invention include Ti, Zr and Hf. All of these IVa group metals have similar chemical properties and high barrier properties. In particular, Ti is the cheapest and is preferred. When these elements or an intermediate layer containing these elements as main components are used as an etching barrier that does not allow the etching solution to reach the opposite side when the metal foil is patterned and removed by etching, the intermediate layer After finishing its role as an etching barrier, since the intermediate layer can be removed by etching with an etchant for removing the intermediate layer, the thickness of the intermediate layer is preferably as small as possible, and the average thickness is 1 μm or less, more preferably 0.1 to 0.1 μm.
A thickness of 0.5 μm is good.

Next, the solid solubility with the IVa group metal is 3 atomic% with each other.
The following metal foil is a metal or the like containing Cu, Fe, Co, Cr, Ni, and W as main components, and may be an alloy such as an Fe-Ni alloy. Among them, Cu and metal foil containing Cu as a main component are suitable for wiring forming materials. This is because, in a printed circuit board for a semiconductor, a transmission efficiency of an electric signal becomes a problem, and therefore, a printed circuit board having good electric conductivity is preferable. Specifically, pure Cu is preferable because etching can be performed uniformly and quickly, and heat dissipation is excellent. Further, when used as a wiring forming material, the thickness is preferably thin to form fine wiring with a narrow line interval, but if too thin, it is difficult to manufacture and handle, and problems such as noise are likely to occur. For these reasons, the thickness is preferably 1 to 18 μm.
More preferably, it is 3 to 12 μm.

In the case where the selective etching technique is used on both sides of the intermediate layer, the metal foil on the other side is also used as described above.
A metal foil having a solid solubility of 4 atomic% or less with the group IVa metal is good, and a metal foil / intermediate layer / metal foil combination suitable for the laminated foil of the present invention is, for example, Cu / Ti / Cu, Cu / Zr / C
u, Cu / Hf / Cu, Cu / Ti / Fe, etc. are good. Among them, Cu / Ti / Cu is suitable for use in wiring boards. Also, in applications where selective etching technology is used only on one side, metals such as Al, which has a solid solubility of more than 3 atomic% with Ti, Zr, Hf, and IVa group metals of the same type as the intermediate layer. Is also good.

Further, for example, when the above-described laminated foil is used for the transfer method, it is possible to use the same material for the carrier material and the wiring forming material so that the etching equipment can be the same, Good because the equipment can be saved. At this time, the thickness of the carrier material is preferably thin for convenience of removal by etching, and is preferably 50 μm or less. More preferably, it is 10 to 30 μm in consideration of handling properties. In addition, the laminated foil application of the present invention is not limited to the above-described transfer method, and is suitable for an application utilizing a selective etching technique at an interface between the intermediate layer and the metal foil disposed on at least one surface side. Needless to say. In addition, it is also possible to form a different pattern from the wiring material by using the above-described carrier material, and in this case, as a thickness of the entire laminated foil,
It is preferably 150 μm or less. Further, even a multilayer structure may be used as long as it has the structure of the present invention in a part thereof.

As described above, when a circuit for transmitting an electric signal is formed on a metal foil on the laminated foil of the present invention, a wiring board can be obtained. With the use of the laminated foil of the present invention, an intermediate layer of a metal having a group IVa metal or a group IVa metal having an excellent etching barrier property as an intermediate layer, the oxygen content at the interface of the metal foil is controlled to be low. Therefore, at the time of selective etching for circuit formation, there is no void that causes interface separation, it is also possible to form fine wiring without defects due to etching, and since the intermediate layer maintains excellent ductility, For example, even after a circuit is formed, even if the resin is pressed against a depressed resin, the function as an etching barrier layer is less likely to be impaired.

[0030]

Embodiments of the present invention will be described below in detail. (Example 1) Suitable for the transfer method which is one of the uses of the present invention
A Cu / Ti / Cu laminated foil was produced by the following steps. First, as a strip of wiring forming material, thickness 10μm, width 200mm, length 500
m rolled copper foil made of pure Cu was used. In addition, a rolled copper foil made of pure Cu having a thickness of 25 μm, a width of 200 mm, and a length of 500 m was used as a band of the carrier material. After previously pickling with 18% by volume hydrochloric acid,
1 x soaked in ethyl alcohol and dried with hot air on one side of each copper foil to an average thickness of 0.1 μm
Pure Ti is deposited in a chamber with a degree of vacuum of 10 ^-2 Pa, and no special heating is performed at a speed of 10 m / min between the Ti-deposited surfaces of the strip forming the wiring material and the strip forming the carrier material. This was pressed by roll rolling at a rolling reduction of about 1% to obtain a laminated foil to be a foil material for a transfer method. At this time, the strip was unwound from an unwinding reel, and was wound up on a take-up reel after vapor deposition and pressure bonding.

The obtained laminated foil is made of a metal foil as shown in FIG.
It is a strip having a cross-sectional structure of an intermediate layer / metal foil. When a peeling test of the wiring forming material and the carrier material was performed on this laminated foil, it was confirmed that the base material was broken and the substrate was strongly bonded without delamination at the interface. Further, the presence or absence of TiO ₂ which deteriorates the bonding strength was confirmed by X-ray diffraction, but no peak was observed. Furthermore, sputtering was performed from the surface at a sputtering rate of 1.5 nm / min by a photoelectron spectrometer, and Cu, Ti, and O were quantitatively analyzed every 3 min. As a result, the oxygen content increased to about 20 atomic% near the Cu / Ti interface, but no oxygen-enriched layer exceeding 50 atomic% was found.

Further, the wiring side surface was covered with a resin film, the carrier material was removed by etching, and further immersed in an etching solution for 30 minutes or more. However, the wiring forming material was not etched, and the Ti intermediate layer was substantially not etched. It was confirmed that there were no defects. The fact that there is substantially no defect in the present invention means that
After removing the carrier material, immerse it in an etchant that does not corrode the barrier layer, confirm whether the wiring forming material is etched through the barrier layer, and judge that there is no defect if it does not penetrate the barrier layer Can be. In addition, when the Ti layer after removing the carrier material was observed at a magnification of 4,000 using an electron microscope, it was confirmed that no tearing occurred.

Further, using the above-mentioned Cu / Ti / Cu laminated foil,
A wiring board having a wiring pattern such that minimum line / space = 50 μm / 50 μm was produced by a transfer method. As a result, no peeling of the pattern due to insufficient bonding, no destruction of the wiring due to lack of barrier properties, and no residual melting of the intermediate layer were recognized, and a good wiring board was obtained.

(Example 2) Cu / Ti / Cu produced in Example 1
Was subjected to a heat treatment at 190 ° C. for 2 hours to obtain a laminated foil to be a foil material for a transfer method. FIG. 3 shows a transmission electron micrograph near the intermediate layer. An intermetallic compound layer (5) having a thickness of about 20 nm is formed between the intermediate layer (1), the wiring forming material (7), and the carrier material (6). When a peeling test was performed between the wiring forming material and the carrier material, it was confirmed that the base material was broken and the bonding was firmly performed without causing interface separation. In addition, an etchant immersion test was performed for the barrier properties in the same manner as in Example 1, but no barrier destruction was observed. Further, a wiring board was formed by a transfer method using this laminated foil, and a good wiring board was obtained.

(Comparative Example) First, a carrier material having a thickness of 25
Use rolled copper foil made of pure Cu with μm, width 200mm, length 200mm
Was. Beforehand, degrease one side of the copper foil with acetone, and
1 × 10 ^-FourPa vacuum chamber
Pure Ti is sputtered inside to form a barrier film on the carrier material.
Thickness, which is used as a wiring forming material on the surface
25μm Cu formed by sputtering to be used as foil material for transfer method
A layer foil was obtained.

When a peeling test was performed on the laminated foil between the wiring forming material and the carrier material, the laminated foil was peeled off at an interface between the carrier material and the intermediate layer with a peeling strength of 0.01 N / mm or less. Moreover, 1.5 nm /
Sputtering was performed at a sputtering rate of min, and Cu, Ti, and O were quantitatively analyzed every 3 min. As a result, an oxygen-enriched layer having an oxygen content exceeding 50 atomic% was found near the Cu / Ti interface, and the thickness was 0.13 μm.

When the carrier material side surface is covered with a resin film and the wiring forming material is removed by etching, peeling occurs at the interface between the carrier material and the Ti intermediate layer, the film is broken, the barrier property is lost, and the carrier material is lost. Corroded.

[0038]

According to the present invention, a method for producing a laminated foil having a high adhesive strength can be obtained by optimizing the surface treatment method of a metal foil disposed on both sides of the intermediate layer. Can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a laminated foil of the present invention.

FIG. 2 is a schematic sectional view showing an example of the laminated foil of the present invention.

FIG. 3 is a sectional view showing an example of the laminated foil of the present invention.
(a) is a transmission electron micrograph, and (b) is a schematic diagram.

FIG. 4 is a schematic sectional view showing an example of a transfer method.

[Explanation of symbols]

1. 1. middle layer; 2. metal foil; 3. oxygen-enriched layer; 4. diffusion layer 5. intermetallic compound layer; 6. carrier material; 7. wiring forming material; 8. dry film resist, 10. Epoxy resin for semiconductor; Foil material for transfer method

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hiroshi Takashima 2107-2 Yasugi-cho, Yasugi City, Shimane Prefecture F-term in Hitachi Metals, Ltd. Metallurgical Research Laboratories 4E351 BB30 DD04 DD11 DD54 GG01 4F100 AB01A AB01C AB12B AB17A AB17C AB19B AB31B AB33A AB33B AB33C BA03 BA06 BA44 EH66 EJ19 EJ41 GB43 4K029 AA02 AA25 BA17 BD10 CA01 EA01 FA04 GA00 GA01 JA10 KA03

Claims (15)

[Claims] 1. A laminated foil having an intermediate layer made of a Group IVa metal or an alloy containing a Group IVa metal as a main component, wherein the intermediate layer is a dry film-forming layer, and both the intermediate layer and the intermediate layer From the interface with the metal foil disposed on the surface side, the IVa
A laminated foil characterized in that an oxygen-enriched layer having an oxygen content of 50 atomic% or more and formed on the alloy side containing a Group IV metal or a Group IVa metal as a main component has a thickness of 0.1 μm or less. 2. An interface between an intermediate layer and a metal foil disposed on at least one surface of the intermediate layer includes a group IVa metal or an alloy containing a group IVa metal as a main component and the metal foil. The laminated foil according to claim 1, wherein a diffusion layer with a metal is formed. 3. The method according to claim 1, wherein at least one surface of the intermediate layer has an IV.
3. The laminated foil according to claim 1, wherein metal foils having a solid solubility of 3 atom% or less with an alloy containing a group a metal or a group IVa metal as a main component are arranged. 4. 4. An interface between an intermediate layer and a metal foil disposed on at least one surface of the intermediate layer includes a group IVa metal or an alloy containing a group IVa metal as a main component and the metal foil. The laminated foil according to any one of claims 1 to 3, wherein an intermetallic compound layer containing a metal as a main component is formed, and the thickness of the intermetallic compound layer is 1 µm or less. 5. The laminated foil according to claim 1, wherein the group IVa metal is Ti. 6. The laminated foil according to claim 1, wherein the metal foil disposed on both sides of the intermediate layer is a metal foil containing Cu as a main component. 7. The metal foil disposed on at least one side of the intermediate layer has a thickness of 50 μm or less, and the entire laminated foil has a thickness of 150 μm or less. 7. The laminated foil according to any one of 6. 8. A wiring board formed using the laminated foil according to any one of claims 1 to 7. 9. An intermediate layer made of a Group IVa metal or an alloy containing a Group IVa metal as a main component is a dry film-forming layer, and is formed on a surface of an adhesive surface of a metal foil disposed on at least one surface of the intermediate layer. In the method for producing a laminated foil to be roll-press-bonded by depositing and forming an alloy containing a Group IVa metal or a Group IVa metal as a main component by a dry film forming method, a method of forming a metal foil disposed on both surfaces of the intermediate layer. A method for producing a laminated foil, wherein a surface cleaning treatment is performed on a surface on an adhesion side before dry film formation. 10. The method for producing a laminated foil according to claim 9, wherein the laminated foil that has been roll-pressed is heat-treated at a temperature of 700 ° C. or less. 11. The metal foil disposed on at least one surface side of the intermediate layer is a metal foil having a solid solubility with a Group IVa metal of 3 atomic% or less with respect to each other. 3. The method for producing a laminated foil according to item 1. 12. The method for producing a laminated foil according to claim 9, wherein the group IVa metal is Ti. 13. The method for producing a laminated foil according to claim 9, wherein the metal foil disposed on both sides of the intermediate layer is a metal foil containing Cu as a main component. . 14. The metal foil disposed on at least one side of the intermediate layer has a thickness of 50 μm or less, and the entire laminated foil has a thickness of 150 μm or less. 14. The method for producing a laminated foil according to any one of the above items 13. 15. The method for producing a laminated foil according to claim 9, wherein the metal foil is unwound from an unwinding reel, roll-pressed, and wound up by a take-up reel. .