TWI443226B - Copper foil with resistive film - Google Patents

Description

Copper foil with resistive film layer

The present invention relates to a copper foil having a resistive film layer which is excellent in adhesion of a film and has high peel strength.

As a wiring material of a printed circuit board, a copper foil is generally used. This copper foil is classified into an electrolytic copper foil and a rolled copper foil according to the manufacturing method. The thickness of the copper foil can be arbitrarily adjusted from a very thin copper foil of 5 μm to a thick copper foil of about 140 μm.

These copper foils are bonded to a substrate made of a resin such as an epoxy resin or a polyimide resin to be used as a substrate for a printed circuit. In the copper foil, it is required to sufficiently ensure the bonding strength with the resin as the substrate. Therefore, the electrolytic copper foil is generally used for the rough surface of a so-called mat surface formed at the time of foil formation, and further roughening the surface thereon. Used for processing. Further, the rolled copper foil is similarly applied to the surface thereof by a roughening treatment.

Recently, it has been proposed to further form a thin film layer made of a resistive material on a copper foil as a wiring material (see Patent Documents 1 and 2). In the electronic circuit board, a resistive element is indispensable. However, if a copper foil having a resistive layer is used, an etching solution such as copper (II) chloride is used on the resistive film layer formed on the copper foil to form a resistive element. Exposed.

Therefore, compared with the previous method of surface-mounting the chip resistor element on the substrate by soldering, the surface area of the substrate can be effectively utilized by the built-in substrate of the resistor.

Further, by forming a resistor element inside the multilayer substrate, design restrictions are reduced, and the circuit length can be shortened, whereby electrical characteristics can be improved. Therefore, if a copper foil having a resistive layer is used, soldering can be eliminated or largely omitted, and weight reduction can be achieved. reliability. As described above, a substrate having a resistive film built therein has many advantages.

The copper foil used as the base material in these resistive materials is subjected to surface treatment before the resistive layer is further formed thereon. Therefore, although it is usually different from the copper foil used for general printed circuit board wiring, it is roughened. To ensure the same strength as the resin.

In the case of evaluating the adhesion strength of the resistive material, it is necessary to study the strength between the copper foil and the resistive film and the strength between the resistive film and the resin, and the interface between the two of them is weak in the tensile test or the like. There will be peeling. In either case, the greater the surface roughness, the higher the subsequent strength. The strength is generally considered to be affected by factors such as surface roughness and other surface chemical species (element types).

On the other hand, it is required to suppress the surface roughness of the resistive material because of the formation of a finer resistance circuit required for a high-performance printed circuit board or the improvement of high-frequency characteristics. In order to achieve this, a method of increasing the adhesion strength independent of surface roughness becomes indispensable.

Patent Document 1: Japanese Patent No. 3311338

Patent Document 2: Japanese Patent No. 3452557

The present invention provides a copper foil having a resistive film layer, whereby a resistive film layer is further formed on a copper foil, whereby a substrate of a resistor can be built in, and adhesion thereof can be improved.

In order to solve the above problems, the inventors of the present invention have conducted intensive studies, and as a result, it has been found that it is effective to form a layer for improving the adhesion between the copper foil and the resistive film layer.

According to the above findings, the present invention provides

1) A copper foil having a resistive film layer having a copper-zinc alloy layer having a zinc content of 1000 to 9000 μg/dm ² per unit area on a roughened surface or a glossy surface of the copper foil. a stable layer composed of at least one selected from the group consisting of zinc oxide, chromium oxide, and nickel oxide and having a thickness of between 5 Å and 100 Å is formed on the copper-zinc alloy layer, and the resistive layer is provided with a resistor. A layer of material.

When a copper foil having a resistive film layer is used as a film for a circuit board, it is considered that stabilization of at least one component selected from the group consisting of zinc oxide, chromium oxide, and nickel oxide is formed on the copper foil. The layer, and further forming a resistive layer thereon, can obtain sufficient bonding strength with the copper foil. However, when a copper foil having a reduced roughness is used for the copper foil as the base, there is a problem that the adhesion is insufficient.

The present inventors have found that in order to improve this, it is effective to form a copper-zinc alloy layer having a zinc content per unit area of 1000 to 9000 μg/dm ² before the formation of the above-mentioned stabilizing layer. The improvement of the adhesion between the copper foil and the copper-zinc alloy layer and the stabilizing layer and then the resistive film layer can be evaluated by the peel strength.

A copper-zinc alloy layer having a zinc content per unit area of 1000 to 9000 μg/dm ² is formed on the surface of the copper foil subjected to the following surface treatment as needed. The steps are an important step to increase the strength of the bond. In the copper-zinc alloy layer in which the zinc content per unit area is less than 1000 μg/dm ² , the strength is not increased. Further, in the copper-zinc alloy layer in which the zinc content per unit area exceeds 9000 μg/dm ² , the chemical resistance (corrosion of the etching liquid) is poor, which is not preferable. The reason for this is that the presence of a large amount of zinc causes a problem of a decrease in corrosion resistance.

The copper-zinc alloy layer can be formed by electroplating. The zinc content of the copper-zinc alloy in electroplating is arbitrary. That is, the copper-zinc alloy layer includes a layer in which zinc is diffused into the copper foil after electroplating. The zinc content per unit area in the copper-zinc alloy layer may be 1000 to 9000 μg/dm ² . As a result, the thickness of the copper-zinc alloy layer is approximately equivalent to the range of 100 to 1200 Å.

On the copper-zinc alloy layer thus formed, a stabilizing layer having a thickness of between 5 Å and 100 Å, which is composed of at least one selected from the group consisting of zinc oxide, chromium oxide, and nickel oxide, is formed.

As described above, although the stabilizing layer has a limit in effect, it also has an effect of improving the adhesion to the copper foil.

Zinc oxide, chromium oxide, and nickel oxide are effective as a stabilizing layer, and the like can also be used in combination. The stabilizing layer has a function of preventing oxidative corrosion of the copper foil, preventing decomposition of the dielectric substrate caused by copper, and maintaining stable peel strength. Then, the stabilizing layer is usually between 5Å and 100Å, but it can be set to a thickness of 100Å or more, that is, 200~300Å. thickness. However, if it is less than 5 Å, the function as a stabilizing layer cannot be exerted, and the force is also lowered, which is not preferable.

A resistive film layer is formed on the stabilizing layer thus formed. The resistive film layer is arbitrarily determined according to the circuit design. That is, the type of the resistive material and the film thickness are determined in consideration of the function of the resistive element, and are not particularly limited.

Examples of the material used as the resistive element include materials such as vanadium, tungsten, zirconium, molybdenum, niobium, nickel, and chromium. The relatively high-resistance metal as described above can be used as a separate film or as an alloy film with other elements.

Further, even a material having a relatively low electric resistance such as aluminum, tantalum, copper, iron, indium, zinc or tin can be used as long as it is alloyed with other elements to form a material having a high electric resistance.

For example, a resistive element such as a NiCr alloy or a NiCrAlSi alloy is a material of interest. Further, a material oxide, a nitride, or a telluride selected from the group consisting of oxides, nitrides, and tellurides of the above elements may also be used. As noted above, the choice of such materials is arbitrarily chosen in accordance with the circuit design and should be understood to be not limited to such materials.

When the resistive film layer is formed, a physical surface treatment method such as a sputtering method, a vacuum deposition method, or an ion beam plating method, or a chemical surface treatment method or a plating method such as a pyrolysis method or a gas phase reaction method, or a plating method may be used. It is formed by a wet surface treatment method such as electroless plating.

In general, the plating method has an advantage that it can be manufactured at low cost. Further, since the sputtering method has a uniform thickness and an isotropic property, there is an advantage that a high-quality resistive element can be obtained.

Since the resistive film layer is formed depending on the use of the film, it can be said that the adhesion method or the plating method at this time is preferably selected in accordance with the properties of the above-mentioned resistive film layer.

The copper foil system with a resistive film layer of the present invention

2) A copper foil having a foil thickness of 5 to 70 μm, particularly preferably a copper foil of 5 to 35 μm, can be used. The thickness of the copper foil can be arbitrarily selected depending on the use, but it is also limited by the production conditions, and therefore it is effective to manufacture it within the above range.

3) Further, the present invention provides a copper foil in which a resistive layer is formed on a matte side (rough side) of an electrolytic copper foil or a roughened surface of a rolled copper foil.

The matte surface of the electrolytic copper foil may be further subjected to roughening treatment of adhering agglomerated particles. Further, the rolled copper foil may be roughened as needed. By the above-described roughening treatment, a roughened surface of a low-distribution copper foil or a standard distribution copper foil having an Rz of 0.3 to 10.0 μm can be obtained.

By using the copper foil with the resistive film layer of the present invention, it is not necessary to separately form the resistive element in the circuit design, as long as copper (II) chloride or the like is used on the resistive film layer formed on the copper foil. The etching solution can be used to expose the resistive element, so that the soldering can be made unnecessary or largely omitted, thereby significantly simplifying the packaging step.

Moreover, the number of package parts or solder is reduced, and as a result, the expandable space is small and lightweight. Thereby, the degree of freedom in circuit design can be improved. Moreover, by incorporating a resistor body in the copper foil as described above, the improvement is high. The effect of signal characteristics in the frequency region.

Further, the present invention has an excellent effect of improving the adhesion resistance, which is a disadvantage associated with the copper foil having the resistive film layer, and thus has excellent heat resistance and acid resistance.

Fig. 1 shows an outline of an apparatus for manufacturing an electrolytic copper foil. The apparatus is provided with a cathode barrel in an electrolytic cell that houses the electrolyte. The cathode can 1 is rotated in a state where a part (substantially lower half) is immersed in an electrolytic solution.

An insoluble anode (anode) 2 is provided so as to surround the lower half of the outer circumference of the cathode can 1 . There is a fixed gap 3 between the cathode barrel 1 and the anode 2, and the electrolyte can flow therebetween. Two anode plates are arranged in the device.

In this apparatus, the electrolyte is supplied from below, and the electrolyte passes through the gap 3 between the cathode can 1 and the anode 2, and overflows from the upper edge of the anode 2, and the electrolyte is circulated. A specific voltage can be maintained between the cathode can 1 and the anode 2 via a rectifier.

As the cathode barrel 1 rotates, the thickness of the copper plated from the electrolytic solution increases, and after reaching a certain thickness or more, the green foil 4 is peeled off and continuously wound. The green foil thus produced can be adjusted in thickness by the distance between the cathode can 1 and the anode 2, the flow rate of the supplied electrolyte, or the amount of electricity supplied.

In the copper foil produced by such a copper foil manufacturing apparatus, the surface in contact with the cathode can is a mirror surface (glossy surface), and the surface on the opposite side is a rough surface (matte surface) in which a convex and concave surface exists. The thickness of the electrolytic copper foil can be arbitrarily selected. usually A copper foil having a thickness of 9 μm to 35 μm can be used.

The copper foil thus produced is passed through a purification step of removing the surface oxide film, and further a water washing step. In the purification step, a 10 to 80 g/L aqueous sulfuric acid solution is usually used.

In the above description, the production of the electrolytic copper foil has been described. However, in the rolled copper foil, the ingot and the cast ingot can be subjected to annealing and hot rolling, and further subjected to cold rolling to produce a copper foil having a desired thickness. Since the rolled copper foil is a glossy surface, the roughening treatment can be performed as needed. This roughening treatment can use a known roughening treatment.

One of the roughening processes is as follows. Further, the roughening treatment is also applicable to the shiny side and the matte side (rough side) of the electrolytic copper foil.

Cu ion concentration: 10~30g/L

Sulfuric acid concentration: 20~100g/L

Electrolyte temperature: 20~60°C

Current density: 5~80A/dm ²

Processing time: 0.5~30 seconds

The electrolytic copper foil or the rolled copper foil thus produced is subjected to zinc-copper alloy plating treatment. The groove composition and plating conditions of the zinc-copper alloy plating treatment are as follows.

(Zinc-copper alloy plating bath composition and processing conditions)

Slot composition

CuCN: 60~120g/L

Zn(CN) ₂ : 1~10g/L

NaOH: 40~100g/L

Na(CN): 10~30g/L

pH: 10~13

Tank temperature: 60~80°C

Current density: 100~10000A/dm ²

Processing time: 2~60 seconds

Thereby, a copper-zinc alloy layer having a zinc content of 1000 to 9000 μg/dm ² per unit area can be formed. The above plating is a preferred zinc-copper alloy plating condition. If a copper-zinc alloy layer having a zinc content of 1000 to 9000 μg/dm ² per unit area can be formed, it is not necessary to be limited to the above conditions.

Therefore, galvanization can be performed on copper, followed by heating and diffusion to form a copper-zinc alloy layer. Further, since heat is generally generated in the pressurizing step, the copper-zinc alloy layer can be formed by heating and diffusion as long as galvanizing is formed, so that the above steps can be utilized. The following shows an example of a preferred galvanizing.

(Zinc plating tank composition and plating conditions)

Slot composition

ZnSO ₄ . 7H ₂ O: 50~350g/L

pH: 2.5~4.5

Tank temperature: 40~60°C

Current density: 0.05~0.4A/dm ²

Processing time: 1~30 seconds

Next, a stabilizing layer having a thickness of between 5 Å and 100 Å, which is composed of at least one selected from the group consisting of zinc oxide, chromium oxide, and nickel oxide, is formed on the zinc-copper alloy layer.

As an embodiment, an electrolytic solution containing zinc ions and chromium ions can be used to form a coating layer. As the source of the zinc ions in the electrolytic solution, for example, ZnSO ₄ , ZnCO ₃ , ZnCrO ₄ or the like can be used. As the chromium ion source in the electrolytic solution, a hexavalent chromium salt or a compound such as ZnCrO ₄ , CrO ₃ or the like can be used.

The concentration of zinc ions in the electrolytic solution may be in the range of 0.1 to 2 g/L, preferably 0.3 to 0.6 g/L, more preferably 0.4 to 0.5 g/L. Further, the concentration of chromium ions in the electrolytic solution may be in the range of 0.3 to 5 g/L, preferably 0.5 to 3 g/L, more preferably 0.5 to 1.0 g/L. Moreover, these conditions are only for the conditions for effective plating, and may be set outside the range of the above conditions as needed.

In another embodiment, in order to form the stabilizing layer, nickel oxide, nickel metal, zinc oxide or chromium oxide may be coated or the above-mentioned materials may be coated. The nickel ion source as the electrolytic solution may be either Ni ₂ SO ₄ or NiCO ₃ or the like, or a combination thereof.

The concentration of nickel ions in the electrolytic solution is preferably from 0.2 g/L to 1.2 g/L. Further, a stabilizing layer such as phosphorus as described in U.S. Patent No. 5,908,544 may be used. Furthermore, these conditions are only conditions for effectively forming a stabilizing layer composed of at least one component selected from the group consisting of zinc oxide, chromium oxide, and nickel oxide, having a thickness of between 5 Å and 100 Å, and are also visible. It needs to be set outside the range of the above conditions.

The electrolytic solution may contain other conventional additives such as Na ₂ SO ₄ at a concentration of 1 to 50 g/L, preferably 10 to 20 g/L, more preferably 12 to 18 g/L. It is desirable that the pH of the electrolytic solution is generally in the range of 3 to 6, preferably 4 to 5, more preferably 4.8 to 5.0.

The temperature of the electrolytic solution is preferably from 20 ° C to 100 ° C, preferably from 25 ° C to 45 ° C, more preferably from 26 ° C to 44 ° C.

Fig. 2 is a view showing an outline of a surface treatment apparatus. The symbols contained in Figure 2 are as follows. 11: raw material copper foil (raw foil), 12: copper foil, 14: glossy side, 20: pre-treatment step, 22: pre-treatment tank, 24: lower guide roll, 26: guide roll, 30: wash tank, 32 : Washing nozzle, 34: Washing tank, 40: Stabilizing step, 42: Electric trough, 44: Lower guide roller, 46: Guide roller (cathode roller), 48: Anode, 60: Dryer 62: Heater, 72 : Sputtering device, 76: target, 77: gas conduit, 100: copper-zinc step.

As shown in FIG. 2, in order to apply a current density to the copper foil 12, the anode 48 is arrange|positioned adjacent to each side of the copper foil 12. The guide roller 46 is a cathode roller. When a voltage is applied to the anode 48 by a power source (not shown), a stabilizing layer 49 composed of, for example, zinc oxide and chromium oxide is deposited on the glossy side 14 exposed by the copper foil 12 and On the matte surface 16.

The current density is in the range of from 1 to 100 A/ft ² (about 0.108 to about 10.8 A/dm ² ), preferably from 25 to 50 A/ft ² (about 2.7 to about 5.4 A/dm ² ), more preferably 30 A/ Ft ² (about 3.2A/dm ² ). When a plurality of anodes are provided, the current density can be varied between the anodes.

A suitable plating time is from 1 to 30 seconds, preferably from 5 to 20 seconds, more preferably about 15 seconds. In a particular embodiment, the cumulative processing time is about 3 to 10 seconds on the glossy side, i.e., on the smooth side, and about 1 to 5 seconds on the matte side.

Further, as a preferred example, the molar ratio of chromium ions to zinc ions in the electrolytic solution may be from 0.2 to 10, preferably from 1 to 5, more preferably about 1.4. According to the present invention, the thickness of the stabilizing layer suitable for the copper foil may be from 5 Å to 100 Å. It is preferably 20 Å to 50 Å.

In the above embodiment, the stabilizing layer is composed of chromium oxide and zinc oxide. However, it is possible to form a stabilizing layer only with chromium oxide.

Preferred conditions for applying the grooves of the chromium oxide stabilizing layer are as follows.

1~10g/L CrO ₃ solution (preferably 5g/L CrO ₃ )

pH: 2

Temperature of the tank: 25 ° C

10~30A/ft ^{2 in} 5~10 seconds (1.08~3.2A/dm ² )

Dip treatment: 10 seconds

After the process of forming the stabilizing layer, cleaning is performed. In the cleaning step, for example, a surface of a copper foil (having a stabilizing layer) is sprayed with water mist by a spray device disposed above and below the copper foil, and the surface is washed and cleaned to remove residual electrolysis from the surface. Solution. The cleaned solution can be recovered by a container disposed below the spray nozzle.

The copper foil having a stabilizing layer on the upper surface is further dried. As shown in the embodiment, the forced air dryer is placed above and below the copper foil, and air is ejected from the forced air dryer to dry the surface of the copper foil.

On the copper foil on which the stabilizing layer is formed, a layer composed of a resistive material is further formed. Examples of the resistance layer include a resistive element such as a NiCr alloy or a NiCrAlSi alloy. The layer composed of the resistive material comes from the requirements of the circuit board design, and can be arbitrarily selected. Therefore, it is not necessary to be limited to a specific material.

Further, in order to improve the adhesion to the substrate (bottom material), various decane treatments may be performed on the resistive layer as needed. However, the decane treatment is arbitrary, and the present invention is not limited thereto.

[Examples]

Next, an embodiment will be described. Furthermore, the following examples are written to make the invention of the present application easy to understand, but are not limited thereto. That is, the modifications, the embodiments, and other examples based on the technical idea of the invention of the present application are included in the present invention.

(Example 1)

In this embodiment, an electroplated copper foil having a thickness of 18 μm was used. A copper-zinc alloy layer was formed on the rough side (matte side) side of the electrolytic copper foil.

The copper-zinc alloy layer was subjected to the following treatment conditions to form a copper-zinc alloy layer having a zinc content per unit area of about 3500 μg/dm ² (the latter 2 digits were rounded off). The amount of coating is adjusted by the processing time.

(Slot composition and plating conditions of copper-zinc alloy plating)

Slot composition

CuCN: 90g/L

Zn(CN) ₂ : 5g/L

NaOH: 70g / L

Na(CN): 20g/L

Tank temperature: 70 ° C

Current density: 500A/dm ²

Processing time: 5~20 seconds

Next, about 50 Å of a stabilizing layer composed of zinc oxide-chromium oxide was formed on the copper-zinc alloy layer under the following treatment conditions.

(Stabilization treatment tank composition and processing conditions)

Slot composition

As zinc of ZnSO ₄ : 0.53g / L

Chromium as CrO ₃ : 0.6g/L

Na ₂ SO ₄ : 11g/L

The pH of the tank: 5.0

Tank temperature: 42 ° C

Current density: 0.85~1.6A/dm ²

Plating time: 3~4 seconds

Next, a resistive material of an alloy composed of 80% nickel (Ni) and 20% chromium (Cr) was attached to the above-mentioned stabilizing layer under the following conditions.

Ni/Cr alloy sputtering:

14-inch sputtering device

Power: 5~8kw

Linear speed: 1.4~2.2ft/min (0.43~0.67m/min)

The thickness of the Ni/Cr alloy is about 100 Å, and further, the resistive material has a sheet resistivity of about 160 Ω/square.

The coating layer coated with the above copper foil was analyzed for the normal peeling value, the peeling value after the solder treatment (heat resistance), and the peeling value (hydrochloric acid resistance) after the hydrochloric acid treatment.

Further, the peeling value after the solder treatment is a peeling value measured after immersing in a molten solder bath at 260 ° C for 20 seconds (that is, a state after receiving the heat treatment), that is, a peeling value after the soldering treatment means that the treatment is Peel value after heat impact). This value is used to evaluate heat resistance.

Further, the peeling value after the hydrochloric acid treatment is a peeling value after immersion at room temperature for 1 hour using 18% by weight of hydrochloric acid. That is, the peeling value after the hydrochloric acid treatment was evaluated for hydrochloric acid resistance. The same is true below.

As a result, the normal peeling value was 0.81 kg/cm, the peeling value (heat resistance) after the solder treatment was 0.77 kg/cm, and the peeling value (hydrochloric acid resistance) after the hydrochloric acid treatment was 0.70 kg/cm, after the solder treatment and The hydrochloric acid treatment showed less deterioration and showed good properties.

(Examples 2 to 11) [Zinc content]

Next, as a basic condition of Example 1 showing good characteristics, a copper-zinc alloy layer in which the zinc content per unit area was changed (1000 to 9000 μg/dm ² ) was formed. Similarly, rounding down is performed under 2 digits. The treatment conditions other than the zinc content of the copper-zinc alloy layer were the same as in Example 1. The amount of coating is adjusted by the processing time. The results are shown in Table 1.

Further, for comparison, a copper-zinc alloy layer in which a zinc content other than the conditions of the present invention was formed was shown as Comparative Example 1 and Comparative Example 2.

It can be seen from Table 1 that when the zinc content in the copper-zinc alloy layer is about 3500 μg/dm ² (two digits or less is rounded off) (Example 1), the normal peel strength, heat resistance, and hydrochloric acid resistance are good. Shows the nature of getting balanced.

On the other hand, as the zinc content per unit area increases, the normal peel strength and the heat resistance increase, but the hydrochloric acid resistance tends to decrease. On the contrary, as the zinc content per unit area is reduced, the hydrochloric acid resistance is increased, but the tendency of normal peel strength and heat resistance is lowered.

In Comparative Example 1, it was found that the normal peel strength, the heat resistance, and the hydrochloric acid resistance were both low due to the small zinc content, and in Comparative Example 2, it was found that the normal peel strength and the heat resistance were observed although the zinc content was too large. It is higher, but it is poor in hydrochloric acid resistance and exceeds the allowable limit, so it is not suitable for practical use. As described above, it is understood that the presence of the copper-zinc alloy layer is extremely effective in order to improve the normal peel strength, heat resistance, and hydrochloric acid resistance.

(Example 1 to Example 1-4) [Thickness of Copper Foil]

Next, the conditions of Example 1 showing good characteristics were used as basic, and the normal peel strength, heat resistance, and hydrochloric acid resistance in the case where the thickness of the copper foil was changed were analyzed. The same as Example 1 except that the thickness of the copper foil was changed. The amount of coating is adjusted by the processing time. The results are shown in Table 2.

In the case of Example 1, the electrolytic copper foil having a thickness of 18 μm was used, but when the modification was carried out in the range of 9 μm to 35 μm, the normal peel strength greatly changed depending on the thickness of the foil. That is, as the copper foil is thick As the degree increases, the peel strength also increases.

However, the deterioration rate of the peeling value after the solder treatment and the peeling deterioration rate after the hydrochloric acid treatment did not correspondingly change greatly. Therefore, from the viewpoint of the deterioration rate after the treatment, it is understood that the peel strength after the solder treatment and the peel strength after the hydrochloric acid treatment are not greatly affected by the thickness of the copper foil. The results are shown in Table 2. It is generally believed that an increase in the thickness of the copper foil results in an increase in peel strength.

(Example 12) [Chane treatment]

In the present embodiment, an electroplated copper foil having a thickness of 18 μm and 35 μm is used, and when the rough surface of the electrolytic copper foil is directly used and on the roughened surface, under the same conditions as in the first embodiment, A copper-zinc alloy plating bath was used, and under the same plating conditions as in Example 1, a copper-zinc alloy plating layer was formed.

Furthermore, the conditions of the above roughening treatment are as follows.

Cu ion concentration: 20g / L

Sulfuric acid concentration: 60g/L

Electrolyte temperature: 40 ° C

Current density: 30A/dm ²

Processing time: 5 seconds

By the above, a copper-zinc alloy layer having a zinc content per unit area of about 3500 mg/m ² (the latter 2 digits rounded off) was formed. Next, a stabilizing layer of Cr-Zn oxide was formed on the copper-zinc alloy layer in the same manner as in Example 1.

Further, a resistive material of an alloy composed of 80% of nickel (Ni) and 20% of chromium (Cr) was formed by sputtering on the stabilized layer of the Cr-Zn oxide. The conditions are also the same as in the first embodiment.

Next, on the resistive layer, decane treatment (TEOS: Tetraethoxysilane, tetraethoxydecane) was carried out. The results are shown in Table 3. As shown in Table 3, it is understood that the normal peel strength is increased, so that the decane treatment is effective.

(Example 13) [Cr resistance film]

Under the conditions of the above Example 1, a copper-zinc alloy layer having a zinc content per unit area of about 3500 μg/dm ² (the last 2 digits were rounded off) was formed, and Cr- was formed on the Cu-Zn alloy layer. A stabilizing layer of Zn oxide.

Next, a chrome resistive film is formed by sputtering on the stabilized layer of the Cr-Zn oxide.

The conditions for chrome sputtering are as follows.

Use a 14-inch sputtering device.

Power: 5~8kw

Linear speed: 1.8~2.8ft/min (0.55~0.85m/min)

Thickness of chrome: 6 kinds of 100Å, 1000Å, 1200Å, 2000Å, 3000Å, 4000Å

In the present Example 13, the normal peel strength, the heat resistance, and the hydrochloric acid resistance were analyzed. Since they were the same as in Example 1, they were not shown in the table, but all showed good properties. From the above, it is understood that the type and thickness of the resistance layer are not related, and the formation of the copper-zinc alloy layer is effective.

(Example 14 to Example 14-4) [Ni/Cr/Al/Si alloy resistive film] Under the conditions of the above Example 1, the zinc content per unit area was formed to be about 3500 μg/dm ² (last 2 positions) The copper-zinc alloy layer is rounded off and a chromium-zinc oxide stabilizing layer is formed on the copper-zinc alloy layer.

Next, it consists of 56% nickel (Ni), 38% chromium (Cr), and 4% aluminum (Al) and 2% germanium (Si) as dopants under the following conditions. The alloy is attached to the stabilizing layer of the chromium-zinc oxide.

Ni/Cr/Al/Si alloy sputtering:

14-inch sputtering device

Power: 0.85~2.3kw

Linear speed: 0.49 ft / min (0.15 m / min)

Sheet resistivity: about 90~300Ω/square

In the present Example 14 to Example 14-4, the film of the sheet resistance shown in Table 4 was formed. The normal peel strength, heat resistance, and hydrochloric acid resistance at this time were analyzed, and the same as in Example 1, and as shown in Table 4, all showed good properties. From the above, it is known that it is not related to the Ni/Cr/Al/Si alloy resistance layer, and the formation of the copper-zinc alloy layer is effective.

(Example 15 to Example 15-4) [rolled copper foil]

In this embodiment, a rolled copper foil of 9 μm, 12 μm, 18 μm, and 35 μm was used. The rolled copper foil was subjected to a roughening treatment under the following conditions.

Cu ion concentration: 20g / L

Sulfuric acid concentration: 60g/L

Electrolyte temperature: 40 ° C

Current density: 30A/dm ²

Processing time: 5 seconds

Next, a Zn plating layer of 3500 μg/dm ² was formed on the roughened rolled copper foil under the following conditions. The thickness of the galvanizing is adjusted by the processing time.

Galvanized tank composition:

ZnSO ₄ . 7H ₂ O: 50~350g/L

pH: 3

Tank temperature: 50 ° C

Current density: 0.2A/dm ²

Processing time: 2~3 seconds

The copper foil on which the treated layer was formed was heat-treated at 300 ° C to form a copper-zinc alloy layer. The zinc content per unit area of the thus formed copper-zinc alloy layer was about 3500 μg/dm ² (the last 2 digits were rounded off).

Next, about 50 Å of a stabilizing layer composed of zinc oxide-chromium oxide was formed on the copper-zinc alloy layer under the following treatment conditions.

Stabilization:

As zinc of ZnSO ₄ : 0.53g / L

Chromium as CrO ₃ : 0.6g/L

Na ₂ SO ₄ : 11g/L

The pH of the tank: 5.0

Tank temperature: 42 ° C

Current density: 0.85~1.6A/dm ²

Plating time: 3~4 seconds

Next, a resistive material of an alloy composed of 80% nickel (Ni) and 20% chromium (Cr) was attached to the above-mentioned stabilizing layer under the following conditions.

Ni/Cr alloy sputtering:

14-inch sputtering device

Power: 5~8kw

Linear speed: 1.4~2.2ft/min (0.43~0.67m/min)

The thickness of the Ni/Cr alloy is about 100 Å, and further, the resistive material has a sheet resistivity of about 160 Ω/square.

The coating layer coated with the above copper foil was analyzed for normal peel strength, heat resistance (peel strength after solder treatment), and hydrochloric acid resistance (peel strength after hydrochloric acid treatment). The results are shown in Table 5. As shown in Table 5, the normal peel strength is 0.64 to 1.22 kg/cm, the peel strength after solder immersion is 0.60 to 1.16 kg/cm, and the peel strength after immersion of 18 wt% hydrochloric acid is 0.53 to 1.09 kg/cm. Both show good properties.

Further, in the same manner as in the above Examples 2 to 11, the thickness of the Cu-Zn alloy layer was changed and the results were the same. Therefore, it is understood that the electrolytic copper foil and the rolled copper foil form a copper-zinc alloy layer having a zinc content of 1000 to 9000 μg/dm ² per unit area, which can improve the adhesion (increased normal peel strength), and is resistant to heat and acid. Sexually effective.

[Industrial availability]

In the present invention, by using a copper foil having a resistive film layer built therein, it is not necessary to separately form a resistive element in circuit design, and etching using copper (II) chloride or the like is performed on the resistive film layer formed in the copper foil. The solution can expose the resistive element, so that the solder can be omitted or largely omitted, thereby significantly simplifying the packaging step, and the high frequency is improved by significantly reducing the circuit design and the manufacturing steps, and the built-in resistor body in the copper foil. The effect of the signal characteristics in the area. Further, the present invention has an advantage that the copper foil having the resistive film layer described above can be improved, that is, the adhesion is reduced, and the heat resistance and the acid resistance are excellent. Therefore, the present invention is useful as a printed circuit board.

1‧‧‧cathode roller

2‧‧‧Anode (insoluble anode)

3‧‧‧ gap

4‧‧‧ Raw foil

11‧‧‧Material copper foil (raw foil)

12‧‧‧ copper foil

14‧‧‧Gloss side

20‧‧‧Pre-processing steps

22‧‧‧Pre-treatment tank

24‧‧‧ lower guide roller

26‧‧‧guide roller

30‧‧‧cleaning trough

32‧‧‧Washing nozzle

34‧‧‧cleaning trough

40‧‧‧Safety steps

42‧‧‧Electric trough

44‧‧‧ lower guide roller

46‧‧‧guide roller (cathode roller)

48‧‧‧Anode

60‧‧‧Dryer

62‧‧‧heater

72‧‧‧ Sputtering device

76‧‧‧ target

77‧‧‧ gas conduit

100‧‧‧ copper-zinc step

Fig. 1 is a view showing an outline of an apparatus for manufacturing an electrolytic copper foil.

Fig. 2 is a view showing an outline of a surface treatment apparatus.

12‧‧‧ copper foil

14‧‧‧Gloss side

46‧‧‧guide roller (cathode roller)

48‧‧‧Anode

Claims (3)

A copper foil having a resistive film layer, characterized in that a copper-zinc alloy layer having a zinc content per unit area of 1000 to 9000 μg/dm ² is provided on the roughened surface or the shiny surface of the copper foil, in the copper- a stabilizing layer having a thickness of between 5 Å and 100 Å, which is composed of at least one selected from the group consisting of zinc oxide, chromium oxide, and nickel oxide, is formed on the zinc alloy layer, and the resistive layer is provided with a resistive material. The film layer formed. A copper foil having a resistive film layer as in the first aspect of the patent application, wherein the copper foil has a foil thickness of 5 to 35 μm. A copper foil having a resistive film layer according to claim 1 or 2, wherein a resistive layer is formed on the matte side of the electrolytic copper foil or the roughened side of the rolled copper foil.