JP2001267705A - Metal core material for resin board metal core using the same, resin board using the metal core, method of manufacturing metal core material for resin board and method of manufacturing the metal core for resin board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal core material for resin boards which has superior etching characteristics and low thermal expansion characteristic compatible with each other and a high heat conduction characteristics, a metal core using the same, resin board using the metal core, a method of manufacturing the metal core material for resin boards and a method of manufacturing the metal core for resin boards. SOLUTION: The material for making a metal core provided in a resin board is a low-thermal expansion metal material having a mean thermal expansion coefficient of 10 ppm/ deg.C or less and a diffraction line integral strength ratio of 70% or more on the (200) plane. The sum of diffraction line integral intensities is set to 100% on principal orientation planes (111), (200), (220) and (311) detected when the crystal orientation of the surface of the low-thermal expansion metal material is measured by the X-ray diffraction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin substrate used for a circuit board and a semiconductor package of an electronic device, and a material for a metal core for a resin substrate which is disposed inside the resin substrate to reduce the thermal expansion of the resin substrate. The present invention relates to a method for manufacturing a metal core using the same, a material for a resin substrate and a metal core for the resin substrate using the metal core, and a method for manufacturing a metal core for the resin substrate.

[0002]

2. Description of the Related Art In recent years, electronic devices typified by portable information and communication terminals have been remarkably enhanced in function and reduced in size. Semiconductor chips used in these electronic devices are mounted on a circuit board at a high density. Flip-chip method for surface mounting on a circuit board with a size of PBGA (Plastic
A lattice terminal type package represented by a Ball Grid Array) is employed.

[0003] As a specific example, a typical example of a semiconductor chip mounting form by a flip chip method is schematically shown in FIG.
To The semiconductor chip (1) is directly connected to a resin substrate constituting a circuit board (3) via a solder ball (2). A wiring pattern (4) is formed in multiple layers inside the circuit board, and through holes (5) are used to electrically connect each layer.
A through-hole, which is called a through-hole, is provided in the thickness direction. An electric conductive layer (6) is formed on the inner surface of the through hole by copper plating, etc.
Conduction of each layer is obtained.

FIG. 2 schematically shows the structure of a PBGA. A semiconductor chip (1) is connected to a resin substrate called an interposer (7) via a solder ball (2). The interposer is connected to the circuit board (3) via the solder balls (2). In order to electrically connect the solder ball on the semiconductor chip side and the solder ball on the circuit board side, the above-mentioned through hole (5) is also provided in the interposer. In order to reinforce the interposer, a metal frame (8) called a stiffener or a support ring may be used. In addition, a metal heat radiating member (9) called a heat spreader may be used for heat radiation of the semiconductor chip.

[0005] Epoxy resin, BT (bismaleimide / triazine) resin, polyimide resin, polybutadiene resin, phenol resin, LCP (liquid crystal polymer) and the like are used for the circuit board and the resin substrate used as the interposer. . The thermal expansion coefficient of these resins is about 12-16 ppm / ° C
(30 to 150 ° C.), which is about four times as large as the thermal expansion coefficient of silicon as a semiconductor chip (about 3.5 ppm / ° C.). Therefore, in the above-described flip-chip method and PBGA, when the temperature change accompanying the heat generation of the semiconductor chip repeatedly occurs, the connection portion of the solder ball is broken due to the difference in the amount of thermal expansion and contraction between the semiconductor chip and the resin substrate. Serious problems could occur.

In order to solve the above-mentioned problem, it is required to reduce the thermal expansion of the resin substrate to reduce the thermal expansion difference with the semiconductor chip. Means for reducing the thermal expansion of the resin substrate include disposing a metal layer having low thermal expansion characteristics (hereinafter, referred to as a low thermal expansion metal material) inside the resin substrate to suppress the thermal expansion of the resin substrate. The schematic diagrams shown in FIGS. 1 and 2 include a metal layer that suppresses the thermal expansion of the resin substrate. This metal layer is referred to as a metal core (10), and is referred to as a metal core for a resin substrate (hereinafter referred to as a metal core for the present invention). , Metal core).

As the form of the metal core, when the low thermal expansion metal material is used alone, and when the low thermal expansion metal material has a low electric conductivity and a low heat conductivity, the purpose is to provide these electric conduction characteristics and the heat conduction characteristics. As shown in FIG. 4, a metal layer (12) containing Cu as a main component is formed on one or both of the front and back surfaces of the low thermal expansion metal material (11) to improve the electrical conductivity and the thermal conductivity. Metal cores have also been proposed.

That is, the characteristics required of the metal core are, first, to have a specific thermal expansion characteristic. Secondly,
There is a need for a specific thermal expansion characteristic to which more excellent thermal conductivity is imparted. Then, as shown in FIG. 3 and FIG. 4, it is necessary to previously provide a through hole in the metal core at a position where the through hole (5) is arranged by etching. In particular, it is necessary when the metal core and the electric conduction layer inside the through hole are not electrically connected to avoid contact between the metal core and the electric conduction layer.

In particular, in recent years, interposers have been required to have high-density wiring with a through-hole diameter of 200 μm or less and a through-hole interval of 500 μm or less. As a third property required and required for the metal core, an excellent etching property has been required.

[0010]

SUMMARY OF THE INVENTION The present inventor has developed a new metal core having a thermal expansion characteristic and a heat conduction characteristic. The following findings were obtained as a result of intensive studies on various metal core materials. First, when etching into a low thermal expansion metal material which is a material of the metal core, the inside of the processed through hole which becomes a through hole may remain in a protruding shape, and in particular,
When etching is performed from both sides, the vicinity of the center of the thickness tends to remain in a protruding shape. When etching is performed from one side, a projection is formed on the side opposite to the side on which the etchant is sprayed.

FIG. 5 is a schematic sectional view showing the inside of a through hole of a metal core when etching is performed from both sides. In this figure, the protrusion that is left undissolved by the etching process is called an edge (13). This edge is likely to occur when the amount of etching that proceeds in the plane direction is greater than the amount of etching that proceeds in the plate thickness direction.If the generated edge protrudes into the inner surface of the through hole and comes into contact with the electric conductive layer, the metal core and the circuit A serious problem arises that the electrical circuit does not function properly due to the short circuit.

The edge can be removed by melting it by lengthening the etching time. However, if the etching is continued to remove the edge, the amount of etching on the surface side on which the etchant is sprayed increases, and becomes larger than the desired diameter of the hole. In addition, when a through hole is provided so as not to contact the edge portion, it is necessary to provide a through hole having a large diameter corresponding to the projection amount of the edge in the metal core with respect to a desired through hole diameter.
As a result, it becomes difficult to reduce the diameter and interval of the through-holes, which is a major obstacle to increasing the density of the through-holes.

Further, as shown in FIG. 4, in the case of a metal core for a resin substrate in which a metal layer containing Cu as a main component is formed on one or both of the front and back surfaces of the low thermal expansion metal material of the metal core for the resin substrate, Due to the difference in the etching rate between the low thermal expansion metal material and the metal containing Cu as a main component, the shape in which the low thermal expansion metal material protrudes becomes sharp. In this case, as shown in FIG. 7, the tip of the protruding low thermal expansion metal material is
Call it 2).

When this edge is generated, it is necessary to form the through hole avoiding the protruding low thermal expansion metal material in order to avoid a short circuit between the electric conductive layer and the metal core in the through hole. For the diameter,
It is necessary to form a through hole in the metal core by adding the amount of protrusion of the low thermal expansion metal material layer. That is, in the case of a metal core in which a metal layer containing Cu as a main component is formed on one or both of the front and back surfaces of a low thermal expansion metal material, it is particularly difficult to increase the density of through holes.

Therefore, the metal core may be made of a low thermal expansion metal material alone, or a metal layer mainly composed of Cu may be formed on one or both of the front and back surfaces of the low thermal expansion metal material. It is necessary that the etching rate is high in the thickness direction of the material and that the above-described edges and protrusions are not easily formed.

An object of the present invention is to provide a material for a metal core for a resin substrate, which has both excellent etching characteristics and low thermal expansion characteristics, and also has high thermal conductivity characteristics, a metal core using the same, and a method using the metal core. It is an object of the present invention to provide a method for producing a resin substrate and a material for a metal core for a resin substrate, and a method for producing a metal core for a resin substrate.

[0017]

Means for Solving the Problems The present inventors have conducted intensive studies on the above-mentioned problems, and as a result, determined that the crystal orientation of the surface of the low thermal expansion metal material used as the material for the metal core is a specific amount on the (200) plane. It has been found that by performing the above orientation, the protrusion amount of the edge remaining in the through hole of the metal core after the etching can be reduced. By using this low-thermal-expansion metal material, there is no danger of short-circuiting between the electric conductive layer and the metal core in the through-hole, and a low-thermal-expansion resin substrate metal core capable of pattern design of high-density through-holes can be manufactured And arrived at the present invention.

That is, the present invention relates to a material of a metal core provided in a resin substrate, wherein the material of the metal core is 30 to 20.
It is composed of a low thermal expansion metal material having an average thermal expansion coefficient of 10 ppm / ° C. or less at 0 ° C. When the crystal orientation of the surface of the low thermal expansion metal material is measured by X-ray diffraction, it is a main orientation detected (111), ( This is a material for a metal core for a resin substrate having a diffraction line integrated intensity ratio of the (200) surface of 70% or more, with the sum of the integrated diffraction lines of the (200), (220), and (311) surfaces being 100%.

Preferably, the low thermal expansion metal material is
Contains 30 to 50% Ni by mass%, the balance being substantially Fe
A material for a metal core for a resin substrate, which is a Fe-Ni-based alloy or an Fe-Ni-Co-based alloy in which a part of the Ni is replaced by 20% by mass or less of Co, and the front and back surfaces of the low thermal expansion metal material Is a material of a metal core for a resin substrate in which a metal layer mainly composed of Cu is formed on one or both of them.

In the present invention, a metal core for a resin substrate may be formed by forming a through hole (through hole) in the above-mentioned metal core material. Furthermore, the present invention relates to a metal core provided in a resin substrate, wherein the metal core is at 30 to 200 ° C.
Is formed of a low thermal expansion metal material having an average thermal expansion coefficient of 10 ppm / ° C. or less, and in a cross section passing through the center of the through hole formed by etching in the low thermal expansion metal material, half of the plate thickness t / 2 is defined as the edge of the through hole. S from the edge to the edge formed in the through hole
This is a metal core for resin substrates with an etching factor E defined by the value divided by

The present invention also provides a metal core provided in a resin substrate, wherein the metal core is made of a low thermal expansion metal material having an average coefficient of thermal expansion at 30 to 200 ° C. of 10 ppm / ° C. or less;
Either or both of the front and back sides of the low thermal expansion metal material
A metal layer mainly composed of Cu is formed, and in a cross section passing through the center of the through hole formed by etching, half of the total plate thickness including the metal layer mainly composed of Cu, t / 2, is made mainly of Cu. A metal core for a resin substrate having an etching factor E of 6 or more defined by a value obtained by dividing by a distance s from an edge of a through hole of a metal layer to an edge formed in a low thermal expansion metal material portion in the through hole. Further, the present invention is a resin substrate using the above-described metal core for a resin substrate.

The method for producing a metal core for a resin substrate according to the present invention is characterized in that Ni is contained in an amount of 30 to 50% by mass, and the remainder is substantially composed of Fe-Ni-based alloy or a part of Ni by mass%.
Reduction of Fe-Ni-Co alloy material substituted with less than 20% Co
After cold rolling at 70% or more to make a sheet material, the sheet material is
This is a method for manufacturing a metal core material for a resin substrate that is annealed at 700 ° C. or higher.

Also, an Fe-Ni alloy containing 30 to 50% by mass of Ni by mass% and the balance being substantially Fe or an Fe-Ni alloy in which a part of Ni is replaced by 20% or less by mass of Co. After the Ni-Co alloy is subjected to cold rolling at a rolling reduction of 70% or more to form a thin plate, the thin plate is annealed at 700 ° C or more, and either or both of the front and back surfaces of the annealed thin plate are processed. This is a method for producing a metal core material for a resin substrate, in which a metal layer mainly composed of Cu is joined to the surface side by roll pressing at a rolling reduction of 3% or less, and obtained by these methods for producing a metal core material for a resin substrate. This is a method for manufacturing a metal core of a resin substrate in which a through hole is formed in a material for a metal core for a resin substrate by etching.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. An important feature of the present invention is that, in the metal material used as the metal core, a metal material having a specific thermal expansion characteristic is selected, and the crystal orientation of the surface is set to 70 (200) plane.
% Or more to impart excellent etching characteristics. First, the provision of the low thermal expansion characteristic as a basic characteristic of the material of the metal core for a resin substrate of the present invention will be described.

Since the material of the metal core to be the metal core of the present invention is used for the purpose of suppressing the thermal expansion of the resin substrate, it is evaluated that the material has a lower thermal expansion than that of the resin, and furthermore, the reliability of the electronic equipment. It is necessary that low thermal expansion characteristics be obtained up to the upper limit temperature, and in the present invention, 30 to 20
It was defined as a low thermal expansion metal material having an average thermal expansion coefficient of 10 ppm / ° C. at 0 ° C.

The metal material having such a low thermal expansion characteristic may be an alloy containing 30 to 50% of Ni by mass% and the balance being substantially Fe. Fe-42% Ni alloy, called Invar F
An Fe-Ni-based alloy such as an e-36% Ni alloy can be used. Further, Fe-31% Ni referred to as a super-invar in which a part of the above-mentioned Ni is substituted by 20% or less of Co by mass%. Fe-Ni-Co alloys such as a -5% Co alloy and an Fe-29% Ni-17% Co alloy called Kovar can be used.

In order to impart electric conduction characteristics and heat conduction characteristics to these low thermal expansion metal materials, a metal layer containing Cu as a main component is formed on one or both sides of the low thermal expansion metal material. It can be used as a material for a metal core for a resin substrate having excellent low thermal expansion characteristics, electric conduction characteristics, and heat conduction characteristics. At this time, when a metal layer mainly composed of Cu is formed only on one surface of the low thermal expansion metal material,
Since the warp deformation may occur like a bimetal due to the difference in the amount of thermal expansion and contraction between the two, in order to suppress the warpage deformation of the metal core alone, Cu was used as a main component on both surfaces of the low thermal expansion metal material It is preferable to form a metal layer.

Note that pure Cu and various Cu alloys can be used as the above-mentioned metal material containing Cu as a main component. Pure Cu is the most inexpensive, and has excellent electrical and thermal conductive properties.
Is most preferred.

Next, a description will be given of the excellent etching characteristic which is the greatest feature of the present invention. When the surface of the low thermal expansion metal material as described above is subjected to X-ray diffraction, (111), (20
The main directions of (0), (220), and (311) are detected. Of these, integration on the (200) plane, which greatly affects the etching characteristics, is particularly important, and the sum of the integrated intensities in the main direction described above is 100%.
By integrating 70% or more on the (200) plane as%, the etching rate can be increased and a large etching factor can be obtained, so that the occurrence of edges can be suppressed. Preferably, 90% or more is integrated. But 70
%, The above effect is reduced, and as a preferable upper limit, if the concentration on the (200) plane exceeds 99%, the through-holes may be deformed due to etching. The upper limit should be 99%.

The (200) plane of the crystal orientation referred to in the present invention is a plane index equivalent to the (100) plane. In order to investigate the degree of orientation of the crystal orientation, X-ray diffraction is used in the present invention.In this X-ray diffraction, the (100) plane is not detected, but is detected as a (200) plane equivalent to the (100) plane. . Therefore, in the present invention, in order to avoid confusion, data obtained by X-ray diffraction is described as it is, and the (200) plane is described as a plane index equivalent to the (100) plane. Also, (11
The (0) plane is also described as (220) plane for the same reason.

As described above, as described above, it has a specific low thermal expansion characteristic, and further has both a heat conduction characteristic and an electric conduction characteristic. By forming a through hole (through hole) using the material of a metal core for a resin substrate that has excellent etching characteristics and low thermal expansion characteristics, it is also suitable for resin substrates with electrical and thermal conductivity characteristics. Metal core can be obtained.

Further, the metal core of the present invention has a specific low thermal expansion characteristic as described above, and further has both a heat conduction characteristic and an electric conduction characteristic. Particularly, it is possible to form a pattern of minute and close through holes by etching. Since a metal core material for a resin substrate having a crystal orientation satisfying the requirements is used, an etching factor E defined below is defined as 6 or more as an index showing particularly excellent etching characteristics.

Edges generated during etching are more likely to occur when the amount of etching in the plane direction is larger than the amount of etching in the plate thickness direction. Therefore, as a numerical value indicating that etching in the plate thickness direction is easy and an edge hardly occurs, as shown in FIG. 6, in a cross section passing through the center of a through hole formed by etching, half the plate thickness.
The value obtained by dividing t / 2 by the distance s from the edge of the through hole to the edge formed in the through hole is defined as an etching factor E.

Here, when the distance s from the edge of the through hole to the edge formed in the through hole is actually measured, it is calculated as 1/2 of the difference between the outer diameter OD of the through hole and the inner diameter ID of the through hole. be able to. That is, when compared at the same plate thickness, the larger the etching factor, the smaller the amount of edge protrusion, and it can be said that etching in the plate thickness direction is easy.If the etching factor E is 6 or more, the occurrence of edges can be suppressed,
It is especially important for high density through holes,
If the etching factor E is less than 6, the generated edge protrudes too much into the inner surface of the through-hole, and it is easy to cause serious problems that the electric circuit does not function properly due to the short circuit between the metal core and the circuit. 6
It was specified above.

In the case of a metal core having a metal layer mainly composed of Cu on one or both of the front and back surfaces of the low thermal expansion metal material, the etching rate of the low thermal expansion metal material and the metal layer mainly composed of Cu is increased. Due to the difference, the edge shape of the low thermal expansion metal material is sharpened. As an index of the etching characteristic in this case, as shown in FIG. 7, in the cross section passing through the center of the through hole formed by etching, Cu is used. Half the thickness t / 2 of the total thickness including the metal layer containing the main component as the interval s from the edge of the through hole of the metal layer containing Cu as the main component to the edge formed on the low thermal expansion metal material in the through hole. The resulting value is referred to as the etching factor E.

Here, when measuring the distance s from the edge of the through hole of the metal layer mainly composed of Cu to the edge formed on the low thermal expansion metal material in the through hole, it is necessary to use the metal mainly composed of Cu. It can be calculated as 1/2 of the difference between the outer diameter OD of the through hole of the layer and the inner diameter ID of the through hole at the edge formed in the low thermal expansion metal material.

Also in the case of this structure, when compared with the same plate thickness, it can be said that the larger the etching factor, the smaller the amount of protrusion of the edge and the easier the etching in the plate thickness direction. If this etching factor E is 6 or more, Edge generation can be suppressed and through-hole densification becomes easier, but when the etching factor E is less than 6, the generated edge protrudes too much into the through-hole inner surface, causing a short circuit between the metal core and the circuit. It is easy to cause serious problems that the electric circuit does not work properly.
E was specified to be 6 or more.

Next, the present invention will be described in more detail based on the above-described method of manufacturing the metal core of the present invention and experimental results. First, an example of a method for orienting the crystal orientation of the surface to the (200) plane by 70% or more will be described below. The above-mentioned low thermal expansion metal material is subjected to cold working by cold rolling at a rolling reduction of 70% or more. Here, the rolling ratio is a percentage of the value obtained by subtracting the thickness after rolling from the thickness before rolling and dividing the value by the thickness before rolling. When the X-ray diffraction is performed on the surface of the sample showing the texture and having such a texture deformed by rolling, the degree of orientation of the (220) plane is detected to be high.

Next, the low thermal expansion metal material after cold rolling is
By annealing at 0 ° C. or higher, a texture of (200) plane orientation, which is a recrystallized texture by rolling, is developed, and X-ray diffraction is performed on the surface of the low thermal expansion metal material.
0) The degree of orientation of the plane is detected high. Although the annealing time depends on the thickness and width of the material, if the thickness is, for example, about 100 μm × 200 mm, an annealing time of about 5 minutes is sufficient. Here, when the above-mentioned cold rolling reduction is low, and when the annealing temperature is low, the orientation of the (220) plane that is the deformation texture remains or the crystal orientation becomes random, and the desired (200) plane 70%
A texture oriented as described above cannot be obtained.

According to the method described above, the crystal orientation is
When a low thermal expansion metal material oriented at 0% or more is perforated to form a through hole by etching, the above-mentioned etching factor E of 6 or more can be easily obtained. For example, when etching a metal core made of a Fe-36% Ni alloy with 70% or more orientation on the (200) plane, the etching factor E is about 8, while the orientation ratio of the (200) plane is 50% or less. , The etching factor E is 2 ~
About three.

Actually, when a through hole for a through hole having a diameter of 100 μm is provided in a metal core having a thickness of 100 μm, when the etching factor E is about 2, the edge protrusion amount is about 25.
μm, and an outer diameter of at least 150 μm is required to avoid contact between the electric conduction layer on the inner wall of the through hole and the edge. On the other hand, if the etching factor E described above is about 8 of the present invention metal core, the edge protrusion amount is only 6.25.
μm, and the metal core may be perforated with a minimum outer diameter of 112.5 μm.

The through hole 1 was formed on the surface of the metal core.
The etching factor is
When E is 2, it occupies about 1.78 times the area of the case of 8. That is, in the metal core of the present invention in which the (200) plane orientation degree is 70% or more, the (200) plane orientation degree is 50%.
%, The through-hole density can be increased about 1.78 times as compared with the case of less than 0.1%.

Next, according to the present invention, it is possible to manufacture a metal core in which a metal layer mainly composed of Cu is formed on one or both of the front and back surfaces of the low thermal expansion metal material. As a first method of forming a metal layer mainly containing Cu on the surface of the low thermal expansion metal material, it is possible to form a metal layer mainly containing Cu by plating, for example. However, when formed by electrolytic copper plating or the like, the plating speed is slow, and the plating thickness that can be manufactured is about 10 μm.

If a thicker metal layer mainly composed of Cu is required, it is preferable to use a copper foil such as an electrolytic copper foil or a rolled copper foil. Especially rolled copper foil is 10μm thick
From the above, it is relatively easily available. As a method of joining the copper foil to the front and back surfaces of the low thermal expansion metal material, there is a roll pressing method by clad rolling. For example, by laminating a low-thermal-expansion metal material and a copper foil and rolling at room temperature or in a heated state, it is possible to join the two, and form a metal layer mainly composed of Cu on the surface of the low-thermal-expansion metal material This is the second method.

At this time, when bonding is performed by a normal cladding method,
The rolling reduction for joining should be 50% or more at room temperature and 20 to 30% even in a heated state. Therefore, the degree of orientation of the low thermal expansion metal material surface is reduced by rolling deformation from the state of being oriented 70% or more to the (200) plane, and the number of crystal planes having other orientations increases. That is, an edge is easily generated at the time of etching, the etching factor E becomes small, and the excellent etching characteristics of the product of the present invention may be impaired. Therefore, it is also possible to perform annealing again after joining and re-orientate the (200) plane by recrystallization, but by diffusing Fe and Ni in the low thermal expansion metal material into the copper foil,
This is not an optimal cladding method because the thermal and electrical conductivity of copper is significantly impaired.

Therefore, as a third method of forming a metal layer containing Cu as a main component on the surface of the low thermal expansion metal material, a method that does not cause large deformation due to rolling during roll pressing may be adopted. As a method of joining without using a large rolling reduction, there is joining of active surfaces. For example, by irradiating Ar ions in a plasma atmosphere to each bonding surface of the low thermal expansion metal material and the copper foil, an oxide layer on the surface is removed, the active surfaces are exposed, and then the active surfaces are rolled at a low rate. By rolling the rolls at a reduction ratio, it is possible to join them at a rolling reduction of 3% or less without giving a large deformation. Furthermore, if the rolling reduction at the time of roll pressing is 3% or less, the low thermal expansion metal material disposed in the center of the sheet thickness due to the difference in deformation resistance between the low thermal expansion metal material and the metal layer mainly composed of Cu is used. The phenomenon that the plate thickness is locally different can be avoided.

As a fourth method of forming a metal layer containing Cu as a main component on the surface of the low thermal expansion metal material, a vapor deposition film is formed on each joining surface of the low thermal expansion metal material and the copper foil,
The active vapor-deposited surfaces can be joined to each other by roll pressing. The elements to be deposited here are Cu, N
There is no particular limitation on elements that can be deposited, such as i and Sn. When these active surfaces are joined to each other, it is desirable to perform roll pressure welding in a vacuum or in an inert gas such as Ar in order to avoid oxidation of the formed active surfaces. Further, when the rolling reduction is 3% or less as described above, it is possible to avoid a phenomenon in which the thickness of the low thermal expansion metal material arranged in the center of the thickness is locally different. By joining the low thermal expansion metal material and the copper foil by the clad method by the roll pressing of the low rolling ratio as described above, the same thickness can be formed in a shorter time than by forming by the plating method, and the productivity can be improved. Is greatly improved.

[0048]

EXAMPLES Examples will be described in more detail below. First, hot-rolled materials of Fe-36% Ni alloy, Fe-42% Ni alloy and Fe-29% Ni-17% Co alloy having a thickness of 9.6 mm were prepared.
Next, these materials were rolled to a thickness of 4.0 mm by cold rolling. After annealing at 950 ° C. for 10 minutes in a reducing atmosphere with hydrogen, cold-rolled to a thickness of 1.5 mm, again annealing at 950 ° C. for 10 minutes in a reducing atmosphere with hydrogen, and then cold rolling. It was rolled to 0.80 mm. After annealing at 780 ° C. for 5 minutes in a reducing atmosphere with hydrogen, a cold-rolled metal core material having a thickness of 0.10 mm (100 μm) and a width of 50 mm was prepared by cold rolling.

The material of the metal core of the Fe-36% Ni alloy cold-rolled material was sample No. 1, and the material of the metal core of the Fe-42% Ni alloy cold-rolled material was sample No. 2, Fe-29. The material of the metal core of the cold-rolled material of the% Ni-17% Co alloy is designated as Sample No.3. Next, the above-mentioned metal core material was annealed at 730 ° C. for 5 minutes in a reducing atmosphere with hydrogen to produce a metal core material as an annealed material. Hereinafter, the material of the metal core of the annealed material of Fe-36% Ni alloy is sample No. 4, the material of the metal core of the annealed material of Fe-42% Ni alloy is sample No. 5, and the material of the metal core of Fe-29% -17% The material of the metal core of the annealed material is Sample No. 6. next,
With respect to these sample Nos. 1 to 6, the plane orientation of the texture on the sample surface was measured from the integrated intensity ratio of the X-ray diffraction described above, and the average thermal expansion at 30 to 200 ° C. was measured. Table 1 shows the measurement results.

[0050]

[Table 1]

Next, on the front and back surfaces of the above sample Nos. 1 to 6, Cu
A 50 μm thick rolled copper foil made of oxygen-free copper made of pure copper was bonded as a metal layer mainly containing. 1.33 × 10 ^-2 at the time of joining
In a vacuum chamber decompressed to Pa or less, a sample having a thickness of about 0.5 μm
A vapor deposition layer was provided, and the vapor deposition surfaces were adhered to each other by a rolling roll in a vacuum chamber and roll-pressed. At this time, the rolling by the rolling roll is hardly performed, and the rolling rate is 3
Roll welding was performed at 1% or less. In the present production method, unlike the joining by ordinary clad rolling, the joining is performed between the active vapor-deposited surfaces, so that a large rolling reduction is not required for the joining. Therefore, by performing excessive rolling, samples 1 to 6
The rolling reduction was limited to 3% or less in order to avoid a partial difference in the thickness ratio between the low thermal expansion metal material and the rolled copper foil.

Using the above-mentioned method, a metal core material having a rolled copper foil bonded to both surfaces of sample No. 1, sample No. 2 and sample No. 3 of a metal core material of a cold-rolled material was used as a sample N.
o.7, No.8 and No.9. Similarly, Sample No. 10, Sample No. 10, Sample No. 10, Sample No. 5, Sample No. 5 and Sample No. 6 with rolled copper foil bonded to both sides of Sample No. 6
o.11 and Sample No.12

Next, samples Nos. 1 to 6 manufactured by the above-described method were used.
Etch the metal core material of
A 100 μm through hole for a through hole was prepared and used as a metal core. (A) is added to the end of each sample number. First, as an etching pretreatment, the sample was degreased with an aqueous NaOH solution. The concentration of NaOH is 8% by mass, and the liquid temperature is 60 ° C.
For 1 minute, washed with water and dried. Next, surface conditioning was performed using an aqueous CPE solution. Here, the components of the CPE aqueous solution are:
13% by mass of hydrogen peroxide and ammonium dihydrogen difluoride
2% by mass, the balance being water, immersed at a liquid temperature of 20 ° C. for 30 seconds, washed with water and dried.

Next, a resist pattern in which a hole having a diameter of 100 μm was drawn was formed on both surfaces of the sample.
Perforation was performed by double-sided etching until the thickness became 0 μm. That is, the inner diameter at the edge portion most protruding inside the through hole is 100 μm. The etching was performed using an aqueous solution of ferric chloride at a liquid temperature of 60 ° C. and a spray pressure of 0.147 MPa.

Sample Nos. 1 (A) to 6 after etching as described above
For (A), the through hole was observed from the sample plane with an electron microscope, and the etching factor defined in the present invention was used.
E = t / (2s) was measured. As shown in FIG. 6, the distance s from the edge of the through-hole to the edge was calculated as 1/2 of the difference between the through-hole outer diameter OD and the through-hole inner diameter ID.

Samples Nos. 7 to 12, which are a material of a metal core having a rolled copper foil bonded to the surface, were etched by the following method to form a through hole for a through hole having a diameter of 200 μm.
Metal core was used. (A) is added to the end of each sample number. First, as an etching pretreatment, the oxide layer of the rolled copper foil on the surface was removed with an aqueous HCl solution. HCl concentration is 10
It was immersed at a liquid temperature of 20 ° C. for 1 minute, washed with water and dried. Next, a resist pattern in which a hole having a diameter of 200 μm was drawn was formed on both sides of the sample, and a hole was formed by double-sided etching until the inside diameter of the through hole became 200 μm. That is, inside the through hole, the inner diameter at the edge formed of the low thermal expansion metal material located at the center of the metal core is 200μ.
m. The etching solution uses an aqueous ferric chloride solution,
The test was performed at a liquid temperature of 60 ° C. and a spray pressure of 0.196 MPa.

The above-described etched metal core sample N
As for samples Nos. 7 to 12, through holes were observed from the sample plane using an electron microscope, and the etching factor E = t / (2s) defined in the present invention was measured in the same manner as in Sample Nos. 1 to 6. As described above, in the case of a metal core having a metal layer mainly composed of Cu formed on the surface, half of the total thickness t / 2 is the distance from the edge of the through hole to the edge of the metal layer mainly composed of Cu. The value E divided by s is used as the etching factor. As shown in FIG. 7, the distance s from the edge of the through hole to the edge is determined by the outer diameter OD of the through hole of the metal layer mainly composed of Cu and the inner diameter of the through hole at the edge formed in the low thermal expansion metal material. It was calculated as 1/2 of the difference between IDs. Table 2 shows the measurement results.

[0058]

[Table 2]

As shown in Table 1, the degree of (200) plane orientation of Sample No. 1, Sample No. 2 and Sample No. 3 was 50% or less, and Sample No. 4 and Sample No. In Sample No. 5 and Sample No. 6, a high degree of orientation of 90% or more was obtained. In addition, as shown in Table 2, Sample No. 4, Sample No. 5 and Sample No. 6 using a metal core material as Sample No. 4 (A), Sample No. 5 (A) and Sample No. 6 (A) While the metal core etching factor E is as large as 6 or more,
Sample No. 1, Sample No. 2 (A), Sample No. 2 (A), and Sample No. 3 (A) using Sample No. 1, Sample No. 2, and Sample No. 3 as a metal core material had an etching factor E of 5 or less. is there.

From these results, when the metal core material of the present invention is used as a metal core, the (200) plane orientation degree is adjusted to 70% or more (90% or more in the present embodiment). Therefore, the etching factor is improved, and the through holes can be arranged at a higher density. This means that, for example, when a through hole having an inner diameter of 100 μm is provided, the outer diameter of 142 μm is necessary in the sample No. 2 (A) of the comparative example, but the outer diameter is 116 μm in the sample No. 5 (A) of the present invention. .

Therefore, the through hole 1 is formed on the surface of the metal core.
No. 2 (A) shows that sample No. 5
It occupies about 1.5 times the area of (A). That is,
Sample No. 5 (A) using the sample No. 5 having a (200) plane orientation degree of 90% or more as a material is a sample No. 2 using a sample No. 2 having a (200) plane orientation degree of 50% or less as a material. It is possible to increase the through-hole density by approximately 1.5 times compared to .2 (A).

In the case of Samples Nos. 7 to 12 which are metal core materials in which a rolled copper foil is joined to the surface of a low thermal expansion metal material, the low thermal expansion metal material (sample) having a (200) plane orientation degree of 90% or more was used. Sample No.10 (A), Sample No.11 (A) and Sample No.12 which are metal cores using No.4, Sample No.5 and Sample No.6)
In (A), an etching factor E of 6 or more was obtained. On the other hand, sample No. 7 (A) and sample No. 8 (A) using low thermal expansion metal materials (sample No. 1, sample No. 2 and sample No. 3) having a (200) plane orientation of 50% or less. ) And sample No. 9 (A) have a low etching factor E of about 2 to 3 and are similar to the results of sample No. 1, sample No. 2 and sample No. 3 where the rolled copper foil is not bonded to the surface. The result was.

Therefore, even when a metal core having a surface to which a rolled copper foil is bonded is produced, the degree of (200) plane orientation of the surface of the low thermal expansion metal material used is 70% or more (90% or more in this embodiment).
By doing so, the etching factor E is improved, and through holes can be arranged at a higher density. For example, when providing a through hole with an inner diameter of 200 μm,
Sample No. 7 (A) requires an outer diameter of 274 μm, whereas Sample No. 10 (A) of the present invention has an outer diameter of 228 μm. Comparing this with the area occupied by one through hole on the metal core surface,
Sample No. 7 (A) occupies about 1.44 times the area of Sample No. 10 (A). In other words, (20)
0) Sample No. 10 (A) made of a material with a plane orientation degree of 90% or more
Sample No. 7 using a material with a (200) plane orientation of 50% or less
Through hole density can be increased about 1.44 times as compared with (A).

By arranging the above-described metal core in the resin substrate, it is possible to lower the thermal expansion of the resin substrate and to arrange the through holes with high density. Therefore, while reducing the difference in thermal expansion with the semiconductor chip, the connection reliability with the semiconductor chip is excellent, and at the same time,
A resin substrate having high-density wiring can be obtained.

[0065]

According to the present invention, with respect to a resin substrate used for a circuit board and a semiconductor package of an electronic device, a protrusion of an edge generated at the time of etching is reduced in a metal core arranged for low thermal expansion. Through holes can be made. In the future, the present invention will be an indispensable technology for realizing high-density wiring of a resin substrate by increasing the density of through holes.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of a usage example of a metal core.

FIG. 2 is a schematic view showing an example of a usage example of a metal core.

FIG. 3 is a schematic diagram illustrating an example of a metal core.

FIG. 4 is a schematic diagram illustrating an example of a metal core.

FIG. 5 is a schematic view showing a projection formed inside a through hole of a metal core.

FIG. 6 is a schematic view showing a method for measuring an etching factor of a metal core.

FIG. 7 is a schematic diagram showing a method for measuring an etching factor of a metal core.

[Explanation of symbols]

1 semiconductor chip, 2 solder balls, 3 circuit board, 4
Wiring pattern, 5 through hole, 6 electric conduction layer, 7
Interposer, 8 metal frame, 9 metal heat dissipation member, 10 metal core, 11 low thermal expansion metal material, 12
Cu-based metal layer, 13 edges

Claims (11)

[Claims] 1. A material of a metal core provided in a resin substrate, wherein the material of the metal core is made of a low thermal expansion metal material having an average thermal expansion coefficient of 30 to 200 ° C. and 10 ppm / ° C. or less;
When the crystal orientation of the surface of the low thermal expansion metal material is measured by X-ray diffraction, the main orientations detected are (111) and (20).
A material for a metal core for a resin substrate, wherein the ratio of the integrated diffraction line intensity of the (200) plane is 70% or more, with the total sum of the integrated diffraction lines of the (0), (220), and (311) planes being 100%. . 2. The low-thermal-expansion metal material contains 30% by weight of Ni.
The material for a metal core for a resin substrate according to claim 1, wherein the material is a Fe-Ni-based alloy containing 50% and the balance being substantially Fe. 3. The low thermal expansion metal material contains a part of Ni by mass%.
3. The material for a metal core for a resin substrate according to claim 2, wherein the material is a Fe-Ni-Co-based alloy substituted with 20% or less of Co. 4. A metal core for a resin substrate, wherein a metal layer mainly composed of Cu is formed on one or both of the front and back surfaces of the low thermal expansion metal material according to claim 1. Material. 5. A metal core for a resin substrate, wherein a through-hole is formed in the metal core material according to any one of claims 1 to 4. 6. A metal core provided in a resin substrate, wherein said metal core has an average thermal expansion coefficient of 10p at 30 to 200 ° C.
Made of a low thermal expansion metal material of pm / ° C or less, and in a cross section passing through the center of the through hole formed by etching the low thermal expansion metal material, half the plate thickness t / 2 is formed in the through hole from the edge of the through hole. A metal core for a resin substrate, wherein an etching factor E defined by a value divided by a distance s to a formed edge is 6 or more. 7. A metal core provided in a resin substrate, wherein the metal core has an average thermal expansion coefficient at 30 to 200 ° C. of 10p.
a cross section passing through the center of a through-hole formed by etching, in which a metal layer mainly composed of Cu is formed on one or both of the front and back surfaces of the low thermal expansion metal material of pm / ° C. or lower. At the edge formed in the low thermal expansion metal material part in the through hole from the edge of the through hole of the metal layer mainly containing Cu A metal core for a resin substrate, wherein an etching factor E defined by a value obtained by dividing by an interval s to 6 is 6 or more. 8. A resin substrate using the resin substrate metal core according to claim 5. Description: 9. An Fe-Ni alloy containing 30 to 50% by mass of Ni in mass%, and the balance being Fe-Ni-based alloy substantially composed of Fe or Fe-in which a part of Ni is substituted by 20% or less by mass of Co. A method for producing a metal core material for a resin substrate, comprising: performing cold rolling on a Ni-Co alloy material at a rolling reduction of 70% or more to form a thin plate material, and annealing the thin plate material at 700 ° C. or higher. 10. An Fe-Ni alloy containing 30 to 50% by mass of Ni in mass%, and the balance being Fe-Ni-based alloy substantially composed of Fe or Fe-in which a part of Ni is substituted by 20% or less by mass of Co. After the Ni-Co alloy is subjected to cold rolling at a rolling reduction of 70% or more to form a thin plate, the thin plate is annealed at 700 ° C. or more, and either or both of the front and back surfaces of the annealed thin plate are processed. A method for producing a material for a metal core for a resin substrate, comprising joining a metal layer mainly composed of Cu to a surface side by roll pressing at a rolling reduction of 3% or less. 11. A resin core metal core for a resin substrate, wherein a through hole is formed by etching in the resin core metal core material obtained by the method for manufacturing a resin substrate metal core material according to claim 9 or 10. Production method.