KR102230999B1 - Surface-treated copper foil and copper clad laminate manufactured using the same - Google Patents

Abstract

The present invention provides a surface-treated copper foil or the like in which reflow heat resistance and transmission characteristics are both achieved at a high level while ensuring sufficient adhesion to an insulating substrate. The surface-treated copper foil of the present invention is a surface-treated copper foil formed by forming a roughened layer 120 on a copper foil base 110, and the roughened layer 120 has an uneven surface formed by roughened particles, In the cross section orthogonal to the surface of the copper foil base, the ratio of the creepage length (Da) measured along the uneven surface of the roughened layer 120 to the creepage length (Db) measured along the surface of the copper foil base (Da /Db) is in the range of 1.05 to 4.00 times, the average height difference H of the irregularities on the surface of the irregularities is in the range of 0.2 to 1.3 µm, and on the roughening layer 120, directly or through an intermediate layer It is characterized by having a silane coupling agent layer formed with a silane adhesion amount of 0.0003 to 0.0300 mg/dm 2.

Description

Surface-treated copper foil and copper clad laminate manufactured using the same

The present invention provides a surface-treated copper foil in which reflow heat resistance and transfer characteristics are both achieved at a high level while ensuring sufficient adhesion with an insulating substrate, and a copper-clad laminate manufactured using the same. About.

In recent years, computers and information communication devices have become high-performance and functional, and with the progress of networking, signals tend to be gradually increased in high frequency in order to transmit and process a large amount of information at high speed. For such information and communication devices, a copper clad laminate is used. The copper clad laminate is produced by heating and pressing an insulating substrate (resin substrate) and a copper foil. In general, a resin having excellent dielectric properties must be used for an insulating substrate constituting a copper clad laminate for high frequency response, but a resin having a low relative dielectric constant or dielectric loss tangent contributes to the adhesion to copper foil. There are few functional groups with high polarity, and the adhesive property with copper foil tends to decrease.

In addition, it is desired to make the surface roughness as small as possible to the copper foil used as the conductive layer for a high-frequency copper clad laminate. The reason why such a low profile of the copper foil is required is because the higher the high frequency, the more current concentrates and flows in the surface portion of the copper foil, so that the larger the surface roughness of the copper foil, the greater the transmission loss tends to be.

In order to improve the adhesion of the copper foil constituting the copper clad laminate to the insulating substrate, the surface of the fine irregularities formed by the electrolysis of roughened particles on the copper foil base (hereinafter simply referred to as irregularities) It is common to form a roughened layer having a surface) to improve adhesion through a physical effect (anchor effect). If the height difference (surface roughness) of the uneven surface is increased, the adhesion is improved, but the transmission loss increases due to the above reasons. In the present situation, the surface of the roughened layer formed on the copper foil base is uneven. Priority is given to making the surface and securing the adhesive force, and it has been tolerated for a certain degree of reduction in transmission loss due to the uneven surface. However, in recent years, development of a next-generation high-frequency circuit board having a corresponding frequency of 20 GHz or more is in progress, and such a board is desired to reduce transmission loss more than before.

In general, in order to reduce transmission loss, for example, it is recommended to use a surface-treated copper foil in which the difference in height (surface roughness) of the surface irregularities of the roughening layer is reduced, or a non-harmonized smooth copper foil not subjected to the roughening treatment. desirable. Further, in order to ensure the adhesion of the copper foil having such a small surface roughness, it is preferable to form a silane coupling agent layer that forms a chemical bond between the copper foil and the insulating substrate.

In the case of manufacturing a high-frequency circuit board using the copper foil, in addition to the above-described adhesion and transmission characteristics, it has become necessary to further consider reflow heat resistance in recent years. Here, "reflow heat resistance" is heat resistance in a solder reflow process performed when manufacturing a high frequency circuit board. The solder reflow process is a method of soldering by heating through a reflow furnace in a state in which pasty solder is attached to the contact between the wiring of the circuit board and the electronic component. In recent years, from the viewpoint of reducing the environmental load, lead (Pb)-free formation of solders used in electrical joints of circuit boards has been promoted. Pb-free solder has a higher melting point than conventional solder, and when applied to the solder reflow process, the circuit board is exposed to a high temperature of, for example, 260°C. It becomes necessary to have reflow heat resistance of. Therefore, in particular, for copper foils used for such applications, it is becoming a new subject to achieve both reflow heat resistance and transmission characteristics at a high level while ensuring sufficient adhesion with an insulating substrate.

In Patent Document 1, for example, after forming fine irregularities on the surface of a thermoplastic resin film using a potassium hydroxide solution, the present applicant sequentially performs electroless copper plating and electrolytic copper plating, resulting from the surface shape of the thermoplastic resin film. A method of producing a metal clad laminate, which is a circuit board excellent in transmission characteristics and adhesion, by forming a copper layer having fine irregularities has been proposed. However, as a result of further examination by the present applicant about the invention described in Patent Document 1 thereafter, it was found that reflow heat resistance may not be sufficiently obtained, and there is room for improvement.

In addition, in Patent Document 2, the present applicant also proposed a surface-treated copper foil having a roughened surface in which the height of a projection formed of roughened particles is 1 to 5 µm at least on one surface of the electrolytic copper foil. The surface-treated copper foil described in Patent Literature 2 has a relatively high height of the protrusions, and is not intended to improve reflow heat resistance, and because the formation of a silane coupling layer is arbitrarily formed, it has excellent adhesion to a liquid crystal polymer film. However, since the surface roughness increases by adhering the roughened particles, the transmission loss tends to increase due to this, and when applied to a high-frequency insulating substrate of 20 GHz or more in recent years, it is not possible to sufficiently cope with it, and furthermore, ripple In some cases, the row heat resistance may not be sufficiently obtained, and there is room for improvement.

In addition, Patent Document 3 discloses a surface-treated copper foil for a copper clad laminate in which roughened particles are formed by roughening treatment using copper-cobalt-nickel alloy plating. When such a copper foil is applied to a high frequency circuit board, since the contact area between the copper foil and the resin increases, good adhesion can be ensured, but since the surface area of the copper foil becomes too large, it is expected that the transmission characteristics are inferior. In addition, the reflow heat resistance is not considered at all.

In Patent Document 4, copper foil in which transmission characteristics, adhesion, and heat resistance are improved by copper roughening treatment is disclosed. In the case of using such copper foil, an improvement in transmission characteristics can be expected, but delamination occurs between the copper foil and the insulating substrate (resin substrate) under heating conditions around 260°C in the reflow test. However, it is not possible to exhibit satisfactory characteristics.

In Patent Document 5, a silane treatment is applied to the surface-treated copper foil with an ultrathin primer resin layer in order to improve the adhesion between the resin and the copper foil, and the adhesion in a steady state is improved. However, when such a silane treatment is performed, generally, uniform treatment of the silane tends to be insufficient, and the heat reflow resistance is adversely affected.

In Patent Document 6, a copper foil for electromagnetic wave shielding is disclosed in which a black or brown treatment layer made of fine roughened particles is formed on one surface of the copper foil. As an example of forming fine roughened particles, for example, electrolysis is performed in a bath to which a chelating agent such as trisodium citrate is added. When the copper foil of the present embodiment is used for a high-frequency substrate, adhesion is excellent, but transmission loss characteristics are lowered due to the influence of fine irregularities on the surface, resulting in insufficient characteristics.

In Patent Document 7, a copper foil in which a copper fine roughened particle treatment layer is applied to at least one surface of a copper foil is disclosed. In Examples, roughened particles are refined by adding pentasodium diethylenetriamine pentaacetic acid as a chelating agent to the roughening plating bath. However, when the copper foil of this embodiment is used for a high-frequency substrate, transmission loss characteristics are lowered due to the influence of fine irregularities on the surface, resulting in insufficient characteristics.

Japanese Unexamined Patent Publication No. 2013-158935 Japanese Patent Publication No. 4833556 Japanese Unexamined Patent Publication No. 2013-147688 International Publication No. 2011/090175 pamphlet International Publication 2006/134868 pamphlet Japanese Laid-Open Patent Publication No. 2006-278881 Japanese Unexamined Patent Publication No. 2007-332418

The present invention responds to high performance and high functionality of information communication devices that increase high frequency in order to transfer and process large amounts of information at high speed, while securing sufficient adhesion with an insulating substrate excellent in dielectric properties with low relative permittivity and dielectric loss tangent. An object of the present invention is to provide a surface-treated copper foil in which row heat resistance and transmission characteristics are both achieved at a high level, and a copper clad laminate manufactured using the same.

(Means to solve the problem)

As a result of extensive research, the present inventors have found that in a cross section perpendicular to the copper foil base surface, the creepage length measured along the uneven surface of the roughened layer with respect to the creepage length Db measured along the copper foil base surface It was found that the Da ratio Da/Db (hereinafter also referred to as "line length ratio") greatly influences the reflow heat resistance. In addition, the present inventors, when performing a roughening treatment such as forming a roughening layer having an uneven surface by electrolysis of roughened particles on a copper foil base, the average height difference H of the uneven surface and the roughness It was also found that copper foil exhibiting excellent properties in the overall characteristics of reflow heat resistance, adhesion, and transmission properties can be obtained by controlling the amount of silane adhesion of the silane coupling agent layer formed on the cotton layer, directly or through the intermediate layer. Came to complete.

That is, the summary structure of the present invention is as follows.

(1) A surface-treated copper foil obtained by forming a roughened layer on a copper foil base, wherein the roughened layer has an uneven surface formed by roughened particles, and in a cross section orthogonal to the copper foil base surface, the copper foil base surface The ratio (Da/Db) of the creepage length (Da) measured along the uneven surface of the roughened layer to the creepage length (Db) measured along the line is in the range of 1.05 to 4.00, and in the uneven surface Having an average height difference (H) of irregularities in the range of 0.2 to 1.3 μm, and having a silane coupling agent layer formed with a silane adhesion amount of 0.0003 to 0.0300 mg/dm 2 directly or through an intermediate layer on the roughened layer. Surface-treated copper foil characterized by this.

(2) The surface-treated copper foil, characterized in that the uneven surface has a constricted shape.

(3) When the ratio (Da/Db) of the creepage length is in the range of 1.05 to 3.20, the average height difference (H) of the unevenness is in the range of 0.2 to 0.8 µm, and when the copper foil and the insulating substrate are laminated, the copper foil base The surface-treated copper foil in which the number of bubbles at the interface between the roughened layer and the insulating substrate is 2 or less on a line of 2.54 µm in the width direction perpendicular to the direction in which the copper foil is manufactured. In addition, the manufacturing direction of a copper foil means the longitudinal direction of a roll in the case of an electrolytic copper foil, and means a rolling direction in the case of a rolled copper foil.

(4) The ratio (Da/Db) of the creepage length is in the range of 1.05 to 1.60, the average height difference (H) of the irregularities is in the range of 0.2 to 0.3 µm, and a line of 2.54 µm in the width direction of the copper foil body The surface-treated copper foil according to claim 1, wherein the number of bubbles at the interface between the roughened layer and the insulating substrate is 1 or less.

(5) The surface-treated copper foil in which the silane adhesion amount of the silane coupling agent layer is 0.0005 to 0.0120 mg/dm 2.

(6) The surface-treated copper foil, wherein the intermediate layer is composed of at least one layer selected from a base layer containing Ni, a heat-resistant layer containing Zn, and an anticorrosive layer containing Cr.

(7) The silane coupling agent layer is an epoxy-based silane, an amino-based silane, a vinyl-based silane, a methacrylic-based silane, an acrylic-based silane, a styryl-based silane, a ureide-based silane, a mercapto-based silane, a sulfide-based silane, and an isocyanate. The surface-treated copper foil consisting of at least one selected from among silanes.

(8) A copper clad laminated plate manufactured using the above-described surface-treated copper foil and having an insulating substrate on the surface of the surface-treated copper foil on the roughened layer side.

(9) A copper clad laminate having an insulating substrate on the side of the roughened layer of a surface-treated copper foil in which a roughening layer is formed on a copper foil base, measured along the copper foil base surface in a cross section orthogonal to the copper foil base surface. The ratio (Da'/Db) of the interface length (Da') measured along the interface between the roughened layer and the insulating substrate to one creepage length (Db) is in the range of 1.05 to 4.00, and at the interface A silane couple having an average height difference (H') of unevenness in the range of 0.2 to 1.3 μm, and an adhesion amount of 0.0003 to 0.0300 mg/dm 2 between the roughened layer and the insulating substrate, directly or through an intermediate layer. A copper clad laminate comprising a ring layer.

(10) The copper clad laminated board described above, wherein the number of bubbles at the interface between the roughened layer and the insulating substrate is 2 or less on a 2.54 µm line in the width direction of the copper foil base.

According to the present invention, it is possible to cope with high-performance and high-functionality of high-frequency information communication devices that transmit and process large amounts of information at high speed, and while securing sufficient adhesion with an insulating substrate excellent in dielectric properties with low relative permittivity and dielectric loss tangent, It is possible to provide a surface-treated copper foil that has both reflow heat resistance and transmission characteristics at a high level. Further, it is possible to provide a copper clad laminate manufactured using the surface-treated copper foil.

Fig. 1(a) is a cross-sectional view showing a state of a roughened layer having a constricted shape according to the present invention. The constricted shape is a shape such that the width of the root of the roughened particle is narrowed compared to the maximum width of the roughened particle as shown in FIG. Fig. 2(b) is a cross-sectional view showing a state of a conventional roughening layer.
Fig. 2 is a cross-sectional view schematically showing the average height difference H of the irregularities constituting the surface of the irregularities constituting the roughening layer.
3 is a cross-sectional view schematically showing the creepage length Da on the uneven surface of the roughened layer shown in FIG. 1.
Fig. 4A is a cross-sectional view showing the base line BL1 for measuring the average height difference H of the irregularities constituting the surface of the irregularities constituting the roughening layer. Fig. 4(b) is a cross-sectional view similarly showing the base line BL2.
5 is a cross-sectional view schematically showing bubbles existing at the interface between the roughened layer and the insulating substrate.

(Form for carrying out the invention)

Hereinafter, an embodiment of the surface-treated copper foil according to the present invention will be described with reference to the drawings. Fig. 1(a) shows a cross-sectional structure when a roughened layer is formed on the surface of a copper foil constituting a typical surface-treated copper foil according to the present invention.

The surface-treated copper foil of the present invention is mainly composed of a copper foil 110, a roughening layer 120, and a silane coupling agent layer (not shown). That is, in the present invention, a surface-treated copper foil is referred to as a surface-treated copper foil 110 in which a roughened layer 120 is formed as a surface treatment, and a silane coupling agent layer (not shown) is further formed as a surface treatment. .

The copper foil 110 can be appropriately selected from among an electrolytic copper foil, an electrolytic copper alloy foil, a rolled copper foil, or a rolled copper alloy foil according to a use or the like.

The roughening layer 120 is formed by performing a roughening treatment on the copper foil base 110, and the surface has a substantially particle-like fine irregularities. In the roughening treatment, by performing electrokinesis with hydrogen generation at a current density exceeding the limit current density, the so-called burn-plating state is formed, forming a particle-shaped electroplated material, and a micron-order fine uneven surface To achieve. In the present invention, such a fine uneven surface is simply referred to as an uneven surface. In addition, the roughened particle in this invention shall refer to this particle-like electrolithography material.

And, in the present invention, in the cross section orthogonal to the copper foil base surface, the (line) of the creepage length Da measured along the uneven surface of the roughened layer 120 with respect to the creepage length Db measured along the copper foil base surface. Length) The ratio Da/Db is set in the range of 1.05 to 4.00. The line length ratio Da/Db may be in the range of 1.05 to 3.20, and the line length ratio Da/Db may be in the range of 1.05 to 1.60.

When the line length ratio Da/Db is less than 1.05, the reflow heat resistance decreases, and satisfactory performance cannot be obtained. When the line length ratio Da/Db exceeds 4.00, the transmission loss increases due to the skin effect and the transmission characteristics deteriorate because the surface irregularities are excessively increased, so the line length ratio Da/Db is 1.05 to 4.00. I made it into the range. In addition, the method of measuring the line length ratio Da/Db will be described later.

As a result of intensive investigation on the reason why the line length ratio Da/Db affects the reflow heat resistance, the following recognition was newly obtained. First, a method of manufacturing a test piece for a reflow heat resistance test will be described. An insulating substrate (substrate) in which copper foil is laminated on both sides is used as a core layer. The core layer is etched with a copper (II) chloride solution or the like, and all copper foils are dissolved and removed. Next, a prepreg layer made of an insulating material and copper foil are laminated on both surfaces of the insulating substrate (substrate) remaining after the core layer is etched to prepare a reflow test piece. As a result of observing the cross section of this reflow test piece, it was confirmed that the surface shape of the copper foil constituting the core layer was replica at the interface where the insulating substrate (substrate) of the core layer and the prepreg layer contacted. In addition, in the reflow heat resistance test, since the sample (test piece) is exposed to a high temperature around 260°C, the low molecular weight component in the insulating substrate (substrate) volatilizes, and the adhesion between the insulating substrate and the prepreg layer is It was confirmed that the gas volatilized stayed in the weak area and caused delamination. Therefore, when the line length ratio Da/Db is less than 1.05, the area to be replicated by etching decreases, and as a result, the area in contact between the insulating substrate (substrate) and the prepreg layer decreases, so that the adhesion between the two layers is low. It is thought that when a region is generated and heated, the gas volatilized from the substrate stays in the region between layers and peeling is likely to occur.

In the present invention, as a result of intensive research, by controlling the line length ratio Da/Db and the average height difference H of irregularities to an appropriate range, a roughened shape having a constricted shape is obtained, compared with a copper foil controlled by a surface area as in a known example. , It has been found that the heat resistance is remarkably improved. That is, if Da/Db is increased to such an extent that the transmission characteristics do not decrease within the range of the average height difference H of the irregularities of the present case, the contour length of the roughened layer is lengthened, and as a result, a roughened shape having many constricted shapes is obtained. By increasing the constricted shape, despite the fine roughness, a strong anchor effect is exhibited, the adhesion between the copper foil and the insulating substrate (resin substrate) is increased, and the heat resistance is improved. Therefore, by controlling Da/Db and the average height difference H in the claims of the present invention, heat resistance is remarkably improved compared to the known examples while maintaining the transmission characteristics at a high level.

As a parameter for quantifying the roughened shape, as shown in Patent Document 4 (WO2011-090175), the surface area ratio measured with a laser microscope is known. However, as a problem, for example, as shown in Fig. 1, when (a) a roughened shape with a constricted shape (11) and (b) a harmonic without a constricted shape exist, in principle, the surface area of the laser microscope is from the vertical direction of the copper foil. Since the height is measured by hitting the laser, it is difficult to measure the difference between the presence or absence of the constricted shape of Figs. 1(a) and 1(b). That is, it is possible to measure the shape of the surface to which the laser light directly touches, but when the laser light is hit from a vertical direction such as a constricted portion, it is impossible to measure the shape of a portion where a shadow is generated and the laser light does not directly touch.

Therefore, when the surface area ratio is measured with a laser microscope as practiced in Patent Document 4, the presence or absence of a constricted shape cannot be reflected in the measured value. Controlling the surface shape is not suitable for this case. In addition, the aspect ratio shown in Patent Document 4 simply represents the ratio of the "height" and the "width" of the roughened particles, and the constricted shape is not considered at all.

In addition, when a copper clad laminate is formed by adhering the insulating substrate to the side of the roughened layer of the copper foil having the roughened layer obtained by the above embodiment, the interface length (Da') measured along the interface between the roughened layer and the insulating substrate Tends to shrink slightly due to pressure and close contact with the insulating substrate. For this reason, it is necessary that the line length ratio is maintained in the above range even after adhesion to the insulating substrate, and in the cross section orthogonal to the surface of the copper foil after adhesion to the insulating substrate, the creepage length (Db) measured along the surface of the copper foil base By making the ratio (Da'/Db) of the interface length (Da') measured along the interface between the roughened layer and the insulating substrate to be in the range of 1.05 to 4.00, as in the case of (Da/Db) The same effect can be obtained.

Therefore, in the present invention, the average height difference (corresponding to the average height of the coarse particles) H of the irregularities on the surface of the copper foil is in the range of 0.2 to 1.3 µm. When the average height difference H of the irregularities on the surface of the irregularities is less than 0.2 µm, the anchor effect is weak, so that sufficient adhesion between the copper foil and the insulating substrate cannot be obtained. Further, when the average height difference H of the irregularities on the surface of the irregularities exceeds 1.3 µm, the surface irregularities become too large, and the transmission loss increases due to the skin effect. In addition, the average height difference H of the irregularities on the uneven surface may be in the range of 0.2 to 0.8 µm, and the average elevation difference H of the irregularities on the surface of the irregularities may be in the range of 0.2 to 0.3 µm.

In addition, when a copper clad laminate is formed by attaching an insulating substrate to the side of the roughened layer of copper foil having a roughened layer obtained by the above embodiment, the unevenness H of the roughened layer slightly decreases due to pressure contact with the insulating substrate. Tend to do. For this reason, it is necessary to keep the average height of the irregularities in the above range even after adhesion to the insulating substrate, and in a cross section orthogonal to the surface of the copper foil after adhesion to the insulating substrate, the average height difference of the irregularities on the surface of the irregularities (harmonized particles Corresponding to the average height of) H'can be obtained in the range of 0.2 to 1.3 µm, thereby obtaining the same effect as in the case of H.

The present inventors investigated a method of controlling Da/Db within the range of the average height difference (H) of appropriate irregularities. As a result, in the harmonic method such as Document 6 or Document 7, the concentration of the chelating agent is high, so a number of fine harmonics It was found that Da/Db increased excessively as particles were formed on the copper foil surface, resulting in deterioration of transmission loss. As a result of intensive research on this countermeasure, by making the concentration of the chelating agent lower than before, the particles become an appropriate size, control Da/Db in the optimum range, and maintain high level of adhesion and heat resistance, and transmission loss characteristics. I found it to improve. Specifically, the concentration of the chelating agent added to the plating bath may be in the range of 0.1 to 5 g/L.

As a mechanism of the reaction, it is presumed that by making the chelating agent at a low concentration, the overvoltage at the time of electrolysis decreases compared to the high concentration condition, so that the frequency of nucleation is lowered, the micronization effect is moderately suppressed, and roughened particles of an appropriate size are formed. In addition, when the chelating agent is at a low concentration, since the number of chelating molecules in the bath is small, metal ions (Cu, etc.) with a large amount of chelating coordination and metal ions not coordinated with the chelate are mixed in the bath, and the coordination of the chelate. It is considered that by simultaneously forming particles having different precipitation modes due to the difference in state, a complex particle shape having a constricted shape is obtained, and both heat resistance and adhesion can be achieved at a high level even in a suitable Da/Db range. In addition, when the chelating agent is low in concentration, the growth of the roughened particles in the height direction is appropriately suppressed, and the average height difference H of the irregularities becomes an appropriate range. By the precipitation mode in a state in which metal ions (Cu, etc.) with a large amount of chelate coordinated and metal ions not coordinated with a chelate are mixed in the bath, the orientation of the precipitation becomes random and growth in the height direction is suppressed. I think it was done.

Further, as a method of appropriately controlling Da/Db, it has been found that a method of adding two types of chelating agents to the roughening treatment bath is also effective. It is presumed that by adding two types of chelating agents, metals having different chelate coordination states are simultaneously electrolyzed, and particles having different shapes are simultaneously precipitated, thereby complicating the shape of the roughened particles, and the anchoring effect is easily expressed.

In addition, as a method of appropriately managing Da/Db, it is also effective to form roughened particles with a current density of 70 to 90 A/dm 2, which is not conventionally used due to problems such as powder dropping. However, if the treatment time is long, the particles grow excessively in the vertical direction and powder fall off becomes easy, so the treatment time needs to be shortened. With a high current density, the amount of hydrogen gas generated on the cathode increases. Since hydrogen becomes a spot that cannot be plated until it escapes from the cathode into the liquid, the timing of the precipitation of roughness becomes discontinuous, and as a result, it is presumed that a surface shape with an appropriate amount of irregularities is obtained.

Further, in the present invention, a silane coupling agent layer formed on the roughened layer 120 at a silane adhesion amount of 0.0003 to 0.0300 mg/dm 2 directly or through an intermediate layer is provided. When the silane adhesion amount of the silane coupling agent constituting the silane coupling agent layer is less than 0.0003 mg/dm 2, the reflow heat resistance decreases. Moreover, when it exceeds 0.0300 mg/dm<2>, the silane coupling agent layer becomes too thick, and adhesive strength rather falls. In addition, the amount of silane adhesion of the silane coupling agent constituting the silane coupling agent layer may be 0.0005 to 0.0120 mg/dm 2.

In addition, as a method of forming the silane coupling agent layer, for example, after applying a silane coupling agent solution directly or indirectly through an intermediate layer on the uneven surface of the roughened layer 120, air drying or heat drying. And a method of forming. Drying of the applied coupling agent layer sufficiently exhibits the effects of the present invention when water evaporates, but is suitable because the reaction between the silane coupling agent and the copper foil is accelerated by heating and drying at 50 to 180°C.

The silane coupling agent layer is preferably an epoxy-based silane, an amino-based silane, a vinyl-based silane, a methacrylic-based silane, an acrylic-based silane, a styryl-based silane, a ureide-based silane, a mercapto-based silane, a sulfide-based silane, and an isocyanate. Contains any one or more of the silanes.

It is preferable that the uneven surface of the present invention has a plurality of constricted shapes. By having a large number of constricted shapes, despite the fine roughness, a strong anchor effect is expressed, and the adhesion between the copper foil and the insulating substrate is increased, and heat resistance can be improved. In order to form the uneven surface having a plurality of constricted shapes, as described above, the average height difference H of the unevenness is within the range of 0.2 to 1.3 μm, and Da/Db is controlled within the range of 1.4 to 4.0, so that the contour length of the roughened layer Becomes longer, and as a result, a harmonic shape having many constricted shapes can be obtained.

Further, in the present invention, when the copper foil and the insulating substrate are laminated, the number of bubbles at the interface between the roughened layer and the insulating substrate is preferably 2 or less in the width of the substrate, for example, 2.54 µm. In this paper, in the investigation of factors affecting reflow heat resistance, in addition to the above line length ratio Da/Db and average height difference H, the number of bubbles at the interface between the roughened layer of copper foil and the insulating substrate in the reflow test piece. I found that the impact was great. Here, the bubble in this case refers to a region in which the insulating substrate is not filled at the interface between the roughened layer and the insulating substrate, and the size is 1.0 µm or less in terms of the long diameter. When the number of bubbles at the interface between the roughened layer of copper foil and the insulating substrate is large, the gas volatilized from the insulating substrate during heating in the reflow test collects in the bubble portion, and the gas pressure in the bubble increases, making it easier to peel between layers. .

Therefore, as a result of intensive investigation of a method of reducing the number of bubbles at the interface between the roughened layer and the substrate, it was found that it is effective to appropriately control the treatment conditions of the silane coupling agent. Specifically, first, it is a method of adding alcohol to an aqueous solution of a silane coupling agent. Examples of alcohol include methanol, ethanol, isopropyl alcohol, and n-propyl alcohol. It is considered that the dispersibility of the silane molecules in the solution is improved by the addition of alcohol, and the wettability to the resin is improved by uniformly treating the silane coupling agent to the roughened layer of the copper foil. And when the substrate and the copper foil are pressed at a high temperature, it is assumed that the molten resin wets the resin well with respect to the roughened layer, so that the filling property improves and the number of bubbles at the interface between the roughened layer and the substrate decreases. In addition, a method of lengthening the time required to dry the copper foil with a warm air after treating the copper foil with an aqueous silane solution is also effective. By extending the time from treatment with the silane aqueous solution to drying with warm air, silane molecules are regularly oriented on the surface of the roughened layer of copper foil, improving the wettability to the resin, and consequently, the roughening layer and the insulating substrate. It is assumed that the number of bubbles at the interface decreases. For example, in the case of the silane treatment introduced in Patent Document 4, the wettability of the resin to the roughened layer is not considered, and the number of bubbles at the interface between the roughened layer and the insulating substrate is liable to increase.

The number of bubbles at the interface between the roughened layer of copper foil and the insulating substrate may be 2 or less on a line of 2.54 µm in the width direction of the substrate. The number of bubbles may be 1 or less or 0 on the same line. When the number of bubbles at the interface between the roughened layer of copper foil and the insulating substrate is 3 or more on the copper wire, gas generated from the insulating substrate during the reflow test concentrates on the bubble portions, and phase-to-phase separation is likely to occur, resulting in reflow heat resistance. (Between the copper foil and the prepreg layer) tends to decrease.

As another embodiment, between the roughening layer 120 and the silane coupling agent layer, at least one layer selected from a base layer containing Ni, a heat-resistant layer containing Zn, and a rust-preventing layer containing Cr You may have an additional intermediate layer of.

In the underlayer containing nickel (Ni), for example, copper (Cu) in the copper foil base 110 or the roughened layer 120 diffuses to the side of the insulating substrate, causing copper damage, resulting in reduced adhesion. When there is a case, it is preferable to form between the roughening layer 120 and the silane coupling agent layer. The underlayer containing Ni contains at least one or more of nickel (Ni), nickel (Ni)-phosphorus (P), and nickel (Ni)-zinc (Zn). Among them, nickel-phosphorus is preferable from the viewpoint of suppressing the remainder of nickel during copper foil etching during circuit wiring formation.

It is preferable to form a heat-resistant treatment layer containing zinc (Zn) when it is necessary to further improve heat resistance. The heat-resistant layer is, for example, zinc, or an alloy containing zinc, that is, zinc (Zn)-tin (Sn), zinc (Zn)-nickel (Ni), zinc (Zn)-cobalt (Co), and zinc. It is preferable to form an alloy containing at least one or more types of zinc selected from (Zn)-copper (Cu), zinc (Zn)-chromium (Cr) and zinc (Zn)-vanadium (V). Among the above, zinc-vanadium is particularly preferable from the viewpoint of suppressing undercuts during etching during circuit wiring formation. In addition, "heat resistance" as used herein refers to a property in which the adhesion strength between the surface-treated copper foil and the insulating substrate is difficult to decrease after laminating an insulating substrate on a surface-treated copper foil and heating to cure the resin, and reflow heat resistance It is a different characteristic.

The rust prevention treatment layer containing Cr may be formed when it is necessary to further improve the corrosion resistance. Examples of the rust-preventing treatment layer include a chromium layer by chromium plating and a chromate layer formed by chromate treatment.

In the case of forming the whole of these three layers, the base layer, the heat-resistant treatment layer, and the rust-prevention treatment layer may be formed on the roughening layer in this order. Only one or two layers may be formed.

Moreover, it is preferable to use the surface-treated copper foil of this invention for manufacture of a copper clad laminated board. The copper clad laminate has an insulating substrate on the surface of the surface-treated copper foil on the side of the roughened layer.

The insulating substrate used for the clad laminate is a thermosetting polyphenylene ether resin, a thermosetting polyphenylene ether resin containing a polystyrene polymer, a resin composition containing a polymer or copolymer of triallyl cyanurate, methacrylic or acrylic modification. One epoxy resin composition, phenol-added butadiene polymer, diallylphthalate resin, divinylbenzene resin, polyfunctional methacryloyl resin, unsaturated polyester resin, polybutadiene resin, styrene-butadiene, styrene-butadiene, styrene-butadiene crosslinking Insulating resins selected from polymers and the like are used.

When manufacturing a copper clad laminated board, it is good to manufacture by making the surface-treated copper foil which has a silane coupling agent layer, and an insulating substrate heat-press and make close contact. Further, a copper clad laminate produced by applying a silane coupling agent on an insulating substrate and making the copper foil having a rust-preventing treatment layer on the outermost surface be in close contact with each other by hot pressing also has an effect equivalent to that of the present invention.

[Production of surface-treated copper foil]

(1) Formation process of the roughening layer

On the copper foil, a roughened layer having an uneven surface is formed by electrolysis of roughened particles.

In order to control the line length ratio Da/Db, it is preferable that (i) the size of roughened particles is appropriately controlled, and (ii) roughened particles having different shapes are easily precipitated at the same time.

From the viewpoint of (i), for example, in order to reduce the frequency of nucleation, a method of reducing the overvoltage during electrolysis can be employed. As a specific example, a low concentration of a chelating agent is exemplified. Alternatively, a method of increasing the current density at the time of performing the roughening treatment to 70 to 90 A/dm 2 and shortening the treatment time may be employed.

Here, the concentration of the chelating agent added to the plating bath for the roughening treatment is preferably 0.1 to 5 g/L. As a chelating agent, chelating agents, such as DL-malic acid, EDTA sodium solution, sodium gluconate, and diethylenetriamine pentaacetic acid sodium (DTPA), etc. are mentioned.

In addition, from the viewpoint of (ii), for example, a technique in which metals having different chelate coordination states are simultaneously electrolyzed can be employed, and as a specific example thereof, adding two kinds of chelating agents to the roughening treatment bath is mentioned. I can. As an example, there is a combination of DL-malic acid and DTPA.

In addition, in order to ensure that the number of bubbles at the interface between the roughened layer and the insulating substrate is 2 or less on a 2.54 μm line in the width direction of the copper foil base, the wettability of the roughened layer to the surface of the insulating substrate. You can adopt the same method of improving. For this purpose, for example, (i) performing a silane coupling treatment so that a silane coupling agent layer is uniformly formed on the roughened layer, (ii) a silane coupling treatment so that silane molecules in the silane coupling agent layer are regularly oriented. There are means, such as to do. As a specific example of (i), a method of adding alcohol to an aqueous solution of a silane coupling agent, and a specific example of (ii) include a method of lengthening the time before drying with warm air after treating the roughened copper foil in an aqueous silane solution. have.

(2) Formation process of the underlying layer

On the roughening layer, an underlayer containing Ni is formed as necessary.

(3) Formation process of heat-resistant treatment layer

A heat-resistant layer containing Zn is formed on the roughening layer or on the underlayer as necessary.

(4) Formation process of rust prevention treatment layer

The copper foil on which the above layer was formed is immersed in an aqueous solution containing a Cr compound having a pH of less than 3.5, if necessary, and subjected to chromium plating at a current density of 0.3 A/dm 2 or more to treat the roughened layer, the underlying layer, or heat resistant treatment. A rust prevention treatment layer is formed on the layer.

(5) Step of forming a silane coupling agent layer

A silane coupling agent layer is formed on the roughening layer, the base layer, the heat-resistant layer, or the rust-preventing layer.

[Manufacture of copper clad laminated plate]

The copper clad laminate of this embodiment is manufactured by the following process.

(1) Fabrication of surface-treated copper foil

According to the above (1) to (5), a surface-treated copper foil is produced.

(2) Manufacturing (lamination) process of copper clad laminate

The surface-treated copper foil and the insulating substrate prepared above are stacked so that the surfaces of the silane coupling agent layer constituting the surface-treated copper foil face each other with the bonding surface of the insulating substrate, and then heated and pressurized to bring the copper into close contact with each other. To prepare a clad laminate.

In addition, what has been mentioned above is only an example of embodiment of this invention, and various changes can be added within a range not departing from the gist of the present invention.

Example

(Example 1)

A surface-treated copper foil was produced on a copper foil base having a thickness of 18 µm (surface roughness Rz of about 0.8 µm) under the following conditions.

(1) formation of a roughened layer

The roughening treatment on the surface of the copper foil base was performed in the order of the roughening plating treatment 1 under the conditions shown in Table 1, followed by the roughening plating treatment 2 shown below to form a roughening layer.

(Roughening plating treatment 2)

Copper sulfate: 13 to 72 g/L as copper concentration

Sulfuric acid concentration: 26-133g/L

Liquid temperature: 18∼67℃

Current density: 3∼67A/dm2

Processing time: 1 second to 1 minute 55 seconds

(2) Formation of the underlayer containing Ni

After the formation of the roughened layer on the surface of the copper foil base, an underlayer (Ni adhesion amount 0.06 mg/dm 2) was formed on the roughened layer by electrolytic plating under the following Ni plating conditions.

<Ni plating conditions>

Nickel sulfate: 5.0 g/L as nickel metal

Ammonium persulfate 40.0g/L

Boric acid 28.5g/L

Current density 1.5A/d㎡

pH 3.8

Temperature 28.5℃

Time 1 second to 2 minutes

(3) Formation of heat-resistant layer containing Zn

After the formation of the base layer, a heat-resistant treatment layer (Zn adhesion amount: 0.05 mg/dm 2) was formed on the base layer by electrolytic plating under the following Zn plating conditions.

<Zn plating conditions>

Zinc sulfate heptahydrate 1 to 30 g/L

Sodium hydroxide 10-300g/L

Current density 0.1-10A/d㎡

Temperature 5~60℃

Time 1 second to 2 minutes

(4) Formation of a rust-preventing treatment layer containing Cr After formation of a heat-resistant treatment layer, a rust-prevention treatment layer (adhered amount of Cr: 0.02 mg/dm 2) by treating on this heat-resistant treatment layer under chromium plating treatment conditions shown below Formed.

<Chrome plating conditions>

(Chrome plating bath)

Chromic anhydride CrO ₃ 2.5 g/L

pH 2.5

Current density 0.5A/d㎡

Temperature 15~45℃

Time 1 second to 2 minutes

(5) Formation of silane coupling agent layer

After the formation of the rust prevention treatment layer, on the rust prevention treatment layer, under the conditions shown in Table 2, methanol or ethanol was added to the aqueous solution of the silane coupling agent, and a treatment solution adjusted to a predetermined pH was applied. Then, after holding|maintaining for a predetermined time, it dried with warm air, and the silane coupling agent layer of the silane adhesion amount shown in Table 3 was formed. In addition, the numerical value of the lower ship part in Table 3 shows that it is a numerical value outside the appropriate range of the present invention.

(Examples 2 to 18)

The roughening plating treatment 1 was performed according to the contents of Table 1, the silane coupling agent treatment was performed according to the contents of Table 2, and the same treatment as in Example 1 was performed except for that.

(Comparative Examples 1 to 7 and 9 to 14)

The roughening plating treatment 1 was performed according to the contents of Table 1, the silane coupling agent treatment was performed according to the contents of Table 2, and the same treatment as in Example 1 was performed except for that.

(Comparative Example 8)

Using a roll-shaped liquid crystal polymer film (Vecster (registered trademark) CT-Z manufactured by Kuraray Co., Ltd.), it was immersed in a potassium hydroxide solution (liquid temperature of 80°C) for 10 minutes for a treatment time and etched to perform a roughening treatment. Subsequently, electroless copper plating was formed on the roughened thermoplastic resin film by the following electroless copper plating bath.

<Electroless copper plating abstinence>

Copper sulfate pentahydrate (as copper component) 19g/L

HEEDTA (chelating agent) 50g/L

Sodium phosphinate (reducing agent) 30g/L

Sodium chloride 20g/L

Disodium hydrogen phosphate 15 g/L

Thereafter, an electrolytic copper plating layer was formed using a copper sulfate bath so that the entire copper plating layer including the electroless copper plating layer formed on the thermoplastic resin film had a thickness of 20 µm. In addition, Comparative Example 8 was produced under conditions satisfying the scope of the invention described in Patent Document 1.

Evaluation of the characteristics of the test piece

Various measurements and evaluations were performed on each test piece, and the results are shown in Table 3.

(1) Measurement of the line length ratio Da/Db and the average height difference H of the irregularities on the surface of the irregularities

The uneven surface 120 of the roughened layer with respect to the creepage length Db measured along the surface of the copper foil base 110 in a cross section orthogonal to the copper foil base surface (surface direction P) indicated by both arrows in FIG. 3 The ratio Da/Db of the creepage length Da measured along the line length is taken as the line length ratio. When the uneven surface of the roughened layer in the cross section forms a shape having more or larger unevenness, the line length ratio becomes large.

As for the line length ratio Da/Db as described above, the cross section of each test piece treated with an ion milling device (Hitachi Seisakusho manufactured: IM4000) was used as a scanning electron microscope (SEM: Hitachi Seisakusho manufactured: SU8020). It observed, and measured by the procedure shown below. The magnification was calculated from an observation image enlarged to 10000 times (the actual width of the field of view in the image of this case was 12.7 µm). The creepage length Da on the uneven surface of the roughened layer was measured by using a SEM observation image with image analysis software Winroof (Mitani Shoji) as shown in a thick line in FIG. 3. In addition, it can be measured in the same way even when other image analysis software is used. As for the magnification of the SEM, a magnification such that the width of the SEM image is in the range of 5 to 15 µm is preferable. In this case, Dan/Dbn was measured in 10 fields of view (n=1-10), and their average value was taken as Da/Db.

Next, the average height difference of the uneven surface was measured as follows. First, the observation magnification is enlarged to 200 times (the actual width of the field of view in the image is 63.5 μm), and at an arbitrary position, the direction of extension of the uneven surface and the horizontal direction of the screen are ±1°. Adjust it so that it is within the range. Next, the observation magnification is enlarged to 10,000 times (the actual width of the field of view in the image is 12.7 μm), and among the irregularities forming the surface of the irregularities projected in the SEM image at an arbitrary position, the bottom that becomes the lowest point position The bottom position of the first concave portion having a position is taken as point A. Subsequently, the bottom position of the second concave portion having the bottom position serving as the lowest point among the remaining concave portions excluding the first concave portion and the concave portion adjacent to the first concave portion is set as point B. Then, the straight line connecting the points A and B is taken as the base line BL1 (Fig. 4(a)). After that, a SEM image of 50,000 times (the actual width of the field of view in the image in this case is 2.54 μm) is the bottom of the third concave portion having the bottom position as the lowest point among the irregularities forming the irregularities surface at an arbitrary position. The base line BL2 is drawn parallel to the base line BL1 so as to pass through the position, and the distance from the base line BL2 to the top point of the convex portion farthest in the vertical direction is measured as the height difference H (Fig. 4(b)). In this example, the elevation differences were measured in five visual fields, respectively, and their average value was taken as the average elevation difference H.

(2) The number of bubbles at the interface between the roughened layer and the insulating substrate

As shown in Fig. 5, the number of bubbles at the interface between the roughened layer 43 and the insulating substrate 42 was measured by the procedure shown below. First, a laminate is produced by pressing the insulating substrate 42 (prepreg layer) and the copper foil 43 under standard press conditions recommended by the insulating substrate manufacturer using a press machine (in this case, as the insulating substrate 42). The lamination was carried out under the press conditions of a press temperature of 200°C, a press pressure of 35 kgf/cm 2, and a press time of 160 minutes using MEGTRON6:R-5670 manufactured by Panasonic Corporation. The cross section of the sieve was enlarged to 50000 times with the scanning electron microscope (the actual width of the field of view in the image in this case is 2.54 μm), and the interface between the roughened layer 43 and the insulating substrate 42 of the laminate was identified. As shown in Fig. 5, the number of bubbles 41 present at the interface between the roughened layer 43 and the insulating substrate 42 on a line having a width of 2.54 μm was measured at 10 locations, respectively, and 10 The average value of the number of bubbles at the locations was taken as the number of bubbles Vi at the interface between the roughened layer 43 and the insulating substrate 42. The bubble in this case means that the insulating substrate is at the interface between the roughened layer and the insulating substrate. It points to an unfilled area, and its size is less than 1.0 μm in long diameter.

(3) Measurement of silane adhesion amount

Fluorescence X-ray analyzer (ZSXPrimus manufactured by Rigaku Co., Ltd., analysis diameter: Φ 35 mm) was analyzed.

(4) Measurement of the line length ratio Da'/Db after adhesion to the insulating substrate and the average height difference H'of the irregularities on the surface of the irregularities

After bonding each copper foil to the insulating substrate, the line length ratio Da'/Db and the average height difference H'of the irregularities on the surface of the irregularities were performed by the same method as the measurement of Da/Db and H described above.

(5) Transmission characteristics (measurement of transmission loss at high frequencies)

After each copper foil was bonded to the insulating substrate, a sample for measurement of transmission characteristics was prepared, and transmission loss in a high frequency band was measured. As the insulating substrate, a commercially available polyphenylene ether-based insulating (Megtron 6 manufactured by Panasonic Corporation) was used. The substrate for transmission loss measurement was adjusted so that the structure was a strip line structure, the conductor length was 400 mm, the conductor thickness was 18 µm, the conductor width was 0.14 mm, the overall thickness was 0.31 mm, and the characteristic impedance was 50 Ω. In the evaluation, the vector network analyzer E8363B (KEYSIGHT TECHNOLOGIES) was used to measure the transmission loss at 10 GHz and 40 GHz. The transmission loss measured when the conductor length was 400 mm was converted into a 1000 mm conductor length as the measurement result of the transmission loss, and the unit was dB/m. Specifically, the value obtained by multiplying the value of the transmission loss measured with a conductor length of 400 mm by 2.5 was taken as the measured value of the transmission loss. The results are shown in Table 3. As for the transmission characteristics, a transmission loss of less than 19.5 dB/m was passed at 10 GHz, and a transmission loss of less than 66.0 dB/m was passed at 40 GHz.

(6) adhesion strength

The adhesion strength between the surface-treated copper foil and the insulating substrate was measured. As the insulating substrate, a commercially available polyphenylene ether substrate was used. The curing conditions of the insulating (resin) substrate were 210°C for 1 hour. For adhesion strength, a universal material tester (manufactured by Tensilon, A&D) was used, copper foil and insulating substrate were adhered, and then the test piece was etched into a circuit wiring of 10 mm width, and the insulation side was double-sided. It was fixed to the stainless steel plate with a tape, and the circuit wiring was peeled at a rate of 50 mm/min in the 90 degree direction, and it was calculated|required. In the initial adhesion, the case where the peel strength was 0.4 kN/m or more was regarded as pass, and the case where the peel strength was less than 0.4 kN/m was judged as disqualified.

(7) Reflow heat resistance (between copper foil and prepreg layer)

First, the manufacturing method of the test piece for a reflow heat resistance test (between a copper foil and a prepreg layer) is demonstrated. Copper foil was laminated on both sides to prepare a reflow test piece (between the copper foil and the prepreg layer). In this case, the size of the reflow test piece (between the copper foil and the prepreg layer) was 100 mm x 100 mm. Next, the prepared test piece was passed through a reflow furnace, and passed 10 times under heating conditions for 10 seconds at a tower temperature of 260°C. After heating under the above conditions, when the swelling occurred, the cross section of the swelling region was observed with a microscope, and it was confirmed whether there was delamination between the copper foil and the prepreg layer. ``○ (Pass)'' for no delamination between the copper foil and the prepreg layer, ``△ (pass)'' for one location between the copper foil and the prepreg layer, and It was judged as "x (failed)" that there were two or more delaminations therebetween. In addition, the content of the reflow test was based on JIS C 60068-2-58.

(8) Reflow heat resistance (between core layer and prepreg layer)

The manufacturing method of the test piece for the reflow heat resistance test (between the core layer and the prepreg layer) will be described. An insulating substrate in which copper foil is laminated on both sides is used as a core layer. The core layer is etched with a copper(II) chloride solution or the like to dissolve all copper foils. A reflow test piece was produced by laminating a prepreg layer as an insulating substrate and a copper foil on both surfaces of the etched core layer. In this case, the size of the reflow test piece (between the core layer and the prepreg layer) was 100 mm×100 mm.

Next, the prepared test piece was passed through a reflow furnace, and passed 10 times under heating conditions for 10 seconds at a tower temperature of 260°C. After heating under the above conditions, ``○ (pass)'' for no delamination occurring between the core layer and the prepreg layer, and ``△ (pass) for delamination at one location between the core layer and the prepreg layer. )", and that the interlayer peeling between the core layer and the prepreg layer was 2 or more locations was determined as "x (failed)". In addition, the content of the reflow test was based on JIS C 60068-2-58.

As is clear from Table 3, in Examples 1 to 18, all of the performances of adhesion to an insulating substrate, transmission characteristics, and reflow heat resistance were at pass levels. On the other hand, in Comparative Example 1, since the line length ratio Da/Db and Da'/Db were small, and the average height difference H and H'of the irregularities on the surface of the irregularities were low, the adhesion strength was low, and the reflow heat resistance was also inferior. In Comparative Example 2, since the line length ratios Da/Db and Da'/Db were large, and the average height difference H and H'of the irregularities on the surface of the irregularities were high, the transmission loss was large and the transmission characteristics were inferior. In Comparative Example 3, since the line length ratios Da/Db and Da/Db' were small, and the amount of silane adhesion was small, the reflow heat resistance was inferior. In Comparative Example 4, since the line length ratio Da/Db and Da'/Db were small, the average height difference H and H'of the irregularities on the surface of the irregularities were low, and the amount of silane adhesion was large, the adhesion strength was low. In Comparative Examples 5 to 7, since the line length ratio Da/Db and Da/Db' was large, the average height difference H and H'was large, and the number of bubbles at the interface between the roughened layer and the insulating substrate was large, the reflow heat resistance was inferior. there was. In Comparative Example 8, since the line length ratio Da/Db and Da'/Db were small, and the average height difference H of the irregularities on the surface of the irregularities was low, the adhesion strength was low. Comparative Examples 9-14 have large line length ratios Da/Db and Da'/Db, and in particular Comparative Examples 9-11 have high transmission loss because the average height difference H and H'of the irregularities on the surface of the irregularities are high, and the transmission characteristics This was behind.

(Industrial availability)

According to the present invention, it is possible to cope with the high-performance and high-functionality of high-frequency information communication devices that transmit and process large amounts of information at high speed, and secure sufficient adhesion with an insulating substrate having excellent dielectric properties with low relative permittivity and low dielectric loss tangent. It has become possible to provide a surface-treated copper foil in which row heat resistance and transmission characteristics are both achieved at a high level, and a copper clad laminate manufactured using the surface-treated copper foil.

11: constricted shape
110: copper foil body
120: roughening layer
Da: Creepage length measured along the uneven surface of the roughened layer
Db: creepage length measured along the copper foil base surface
P: width of the substrate
41: air bubbles
42: insulating substrate
43: roughening layer

Claims (10)

A surface-treated copper foil obtained by forming a roughened layer on a copper foil base, wherein the roughened layer has a plurality of roughened particles, the surface of the roughened layer is constituted as an uneven surface, and the copper foil base surface In the cross section orthogonal to, the ratio (Da/Db) of the creepage length (Da) measured along the uneven surface of the roughened layer to the creepage length (Db) measured along the copper foil base surface is , In the range of 1.05 to 4.00, the average height difference (H) of the unevenness on the uneven surface is in the range of 0.2 to 1.3 μm, the uneven surface has a constricted shape, and on the roughening layer, directly, or A surface-treated copper foil comprising a silane coupling agent layer formed with a silane adhesion amount of 0.0003 to 0.0300 mg/dm 2 through an intermediate layer. delete The method of claim 1,
The ratio (Da/Db) of the creepage length is in the range of 1.05 to 3.20 times, the average height difference (H) of the irregularities is in the range of 0.2 to 0.8 µm. A surface-treated copper foil in which the number of bubbles at the interface between the roughened layer and the insulating substrate is 2 or less on a line of 2.54 µm in the width direction perpendicular to the copper foil manufacturing direction. The method of claim 1,
The ratio (Da/Db) of the creepage length is in the range of 1.05 to 1.60 times, the average height difference (H) of the irregularities is in the range of 0.2 to 0.3 µm, and the width of the copper foil base when the copper foil and the insulating substrate are laminated A surface-treated copper foil having one or less air bubbles at the interface between the roughened layer and the insulating substrate on a line of 2.54 µm in the direction. The method of claim 1,
A surface-treated copper foil in which the silane adhesion amount of the silane coupling agent layer is 0.0005 to 0.0120 mg/dm 2. The method of claim 1,
The surface-treated copper foil, wherein the intermediate layer is composed of at least one layer selected from a base layer containing Ni, a heat-resistant layer containing Zn, and a rust-preventing layer containing Cr. The method of claim 1,
The silane coupling agent layer is composed of epoxy-based silane, amino-based silane, vinyl-based silane, methacrylic-based silane, acrylic-based silane, styryl-based silane, ureide-based silane, mercapto-based silane, sulfide-based silane, and isocyanate-based silane. Surface-treated copper foil consisting of at least one selected from. A copper clad laminate having an insulating substrate on the surface of the surface-treated copper foil on the roughened layer side of the surface-treated copper foil according to any one of claims 1 to 7. delete delete

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