CN108603303A - Surface treatment copper foil and the copper-clad laminated board being fabricated using it - Google Patents

Abstract

The copper-clad laminated board that the present invention is provided a kind of surface treatment copper foil and is fabricated using it, ensures the sufficient adhesion with insulating substrate and has both the reflux heat resistance and transmission characteristic of height.Roughened layer (120) is arranged on copper foil matrix (110) and forms for the surface treatment copper foil of the present invention, it is characterized in that, the roughened layer (120) is formed with convex-concave surface by roughening particle, in the section orthogonal with the copper foil matrix face, along what the convex-concave surface of the roughened layer (120) measured 1.05 to 4.00 times of range is in along the ratio between face length (Db) (Da/Db) along face length (Da) relative to what is measured along copper foil matrix face, and the concave-convex average difference of height (H) of the convex-concave surface is in 0.2 to 1.3 μm of range, and then directly or it is situated between every middle layer with 0.0003 to 0.0300mg/dm on the roughened layer (120)²Silane attaches amount and the silane coupling agent layer that is formed.

Description

Surface-treated copper foil and copper-clad laminate manufactured using it

technical field

The present invention relates to a surface-treated copper foil that ensures sufficient adhesion to an insulating substrate and has both high reflow heat resistance and transmission characteristics, and a copper-clad laminate manufactured using the same.

Background technique

In recent years, with the improvement of performance and functionality of computers and information communication equipment, and the development of networking, there is a tendency to increase the frequency of signals to perform high-speed transmission processing of large-capacity information. Such information and communication equipment uses copper-clad laminated boards. Copper-clad laminates are produced by heating and pressing an insulating substrate (resin substrate) and copper foil. In general, resins with excellent dielectric properties must be used for insulating substrates constituting high-frequency copper-clad laminates. However, resins with low relative permittivity and dielectric loss tangent tend to facilitate adhesion to copper foil. There are few functional groups with high polarity, so that the adhesive properties with copper foil are reduced.

In addition, it is desired that the surface roughness of the copper foil used as a conductive layer used in a copper-clad laminate supporting high frequencies be as small as possible. The reason why such a lower profile of the copper foil is required is that the current tends to flow concentratedly on the surface of the copper foil as the frequency becomes higher, and the larger the surface roughness of the copper foil, the larger 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, a roughened layer having a fine uneven surface (hereinafter simply referred to as the uneven surface) is generally formed on the copper foil substrate. It is formed by electrolysis, so as to improve the adhesion force through physical effects (anchor effect). If the height difference (surface roughness) of the uneven surface is increased, the adhesion force will be improved, but the transmission loss will increase for the above reasons. However, in the current situation, it is still preferable to make the surface of the roughened layer formed on the copper foil substrate into a rough surface to ensure adhesion, and to allow a certain degree of reduction in transmission loss due to the formation of the rough surface. However, the development of next-generation high-frequency circuit boards supporting frequencies above 20 GHz is currently underway, and it is expected that this board can further reduce transmission loss compared to conventional ones.

In general, in order to reduce transmission loss, it is desirable to use, for example, a surface-treated copper foil that reduces the unevenness (surface roughness) of the surface of the roughened layer or unroughened smooth copper foil that has not been roughened. foil. Moreover, in order to ensure the adhesiveness of the copper foil with such a small surface roughness, it is desirable to form a silane coupling agent layer between copper foil and an insulating substrate, and this coupling agent layer forms a chemical bond.

When manufacturing a high-frequency circuit board using such copper foil, reflow heat resistance needs to be further considered recently in addition to the above-mentioned adhesiveness and transmission characteristics. Here, the "reflow heat resistance" refers to heat resistance in a solder reflow process performed when manufacturing a high-frequency circuit board. The so-called solder reflow process is a method of soldering and joining paste solder by heating in a reflow furnace while adhering to the contacts of the wiring of the circuit board and the electronic component. In recent years, lead (Pb)-free solders used for electrical joints of circuit boards have been developed from the viewpoint of reducing environmental load. Compared with conventional solders, lead-free solders have a higher melting point. When applied to the solder reflow process, the circuit board is exposed to high temperatures such as about 260°C. Therefore, it is necessary to have a higher reflow heat resistance. Therefore, it has become a new subject to ensure sufficient adhesion to an insulating substrate and to have both high reflow heat resistance and transmission characteristics, especially for copper foils used in such applications.

The present applicant proposed a method in, for example, Patent Document 1, which uses potassium hydroxide solution to form fine unevenness on the surface of a thermoplastic resin film, and then sequentially performs electroless copper plating and electroplating copper to form a copper layer with fine unevenness. , the fine unevenness is due to the surface shape of the thermoplastic resin film, thereby producing a metal-covered laminate that is a circuit board excellent in transmission characteristics and adhesiveness. However, as a result of the present applicant's repeated studies on the invention described in Patent Document 1, it has been found that the reflow heat resistance may not be sufficiently obtained, and improvement is required.

In addition, the present applicant also proposed in Patent Document 2 a surface-treated copper foil having, on at least one surface of an electrolytic copper foil, a roughened surface having a protrusion formed of roughened particles with a height of 1 to 5 μm. The surface-treated copper foil described in Patent Document 2 has high protrusions, does not intend to improve reflow heat resistance, and forms a silane coupling layer arbitrarily, so it has excellent adhesion to liquid crystal polymer films. , but the surface roughness is increased by attaching roughening particles, so the transmission loss tends to increase, which is insufficient when applied to insulating substrates that support high frequencies above 20 GHz in recent years, and sometimes cannot fully obtain Reflow heat resistance, thus needs to be improved.

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

Patent Document 4 discloses a copper foil in which transmission characteristics, adhesiveness, and heat resistance are improved by roughening treatment of copper. When such copper foil is used, it can be expected that the transmission characteristics will be improved. However, under the heating conditions of about 260°C in the reflow test, delamination and peeling between the copper foil and the insulating substrate (resin substrate) will occur, making it impossible to exert satisfactory characteristics.

In Patent Document 5, silane treatment is performed on a surface-treated copper foil with an extremely thin primer resin layer in order to improve the adhesiveness between the resin and the copper foil, thereby improving the adhesiveness under normal conditions. However, when such a silane treatment is performed, generally, the uniform treatment of silane tends to be insufficient, which adversely affects the heat reflow resistance.

Patent Document 6 discloses a copper foil for shielding electromagnetic waves in which a black or brown treated layer made of fine roughened particles is provided 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 this example is used for a high-frequency substrate, although the adhesion and the like are excellent, the transmission loss characteristics are lowered due to the influence of fine unevenness on the surface, resulting in insufficient required characteristics.

Patent Document 7 discloses a copper foil obtained by applying a copper fine roughened particle treatment layer to at least one surface of the copper foil. In the examples, the roughened particles were made finer by adding pentasodium diethylenetriaminepentaacetate as a chelating agent to the roughening plating bath. However, when the copper foil of the present example is used for a high-frequency substrate, the transmission loss characteristics are lowered due to the influence of the fine unevenness on the surface, resulting in insufficient required characteristics.

prior art literature

patent documents

Patent Document 1: Japanese Patent Laid-Open No. 2013-158935

Patent Document 2: Japanese Patent No. 4833556

Patent Document 3: Japanese Patent Laid-Open No. 2013-147688

Patent Document 4: International Publication No. 2011/090175 Pamphlet

Patent Document 5: International Publication No. 2006/134868 Pamphlet

Patent Document 6: Japanese Patent Laid-Open No. 2006-278881

Patent Document 7: Japanese Patent Laid-Open No. 2007-332418

Contents of the invention

The present invention responds to high-performance and high-functioning information communication equipment that requires high frequency for high-speed transmission and processing of large-capacity information. The surface-treated copper foil with high performance and transmission characteristics and the copper-clad laminate manufactured using it, the relative permittivity and dielectric loss tangent of the insulating substrate are low, so that the dielectric characteristics are excellent.

The inventors of the present invention have repeatedly studied hard and found that: in a section perpendicular to the surface of the copper foil substrate, the creepage length Da measured along the uneven surface of the roughened layer is larger than that measured along the surface of the copper foil substrate. The ratio Da/Db (hereinafter also referred to as "line length ratio") of the creeping length Db greatly affects the reflow heat resistance. In addition, the inventors of the present invention have also found that during the roughening treatment of forming a roughened layer having an uneven surface on a copper foil substrate by electrolysis of roughened particles, by controlling the average height difference H of the uneven surface The amount of silane attached to the silane coupling agent layer formed on the roughened layer directly or through an intermediate layer can obtain a copper foil that exhibits excellent characteristics in terms of reflow heat resistance, adhesion, and transmission characteristics. , thus completing the present invention.

That is, the gist of the present invention is constituted as follows.

(1) A surface-treated copper foil, which is formed by providing a roughened layer on the copper foil substrate, characterized in that the roughened layer forms a concave-convex surface by roughening the particles, and is formed on the surface of the copper foil substrate. Orthogonal section, 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 surface of the copper foil substrate (Da/Db) is in the range of 1.05 to In the range of 4.00, the average height difference (H) of the concave-convex surface of the concave-convex surface is in the range of 0.2 to 1.3 μm, and then directly on the roughened layer or through an intermediate layer, there is a concentration of 0.0003 to 0.0300 mg/dm A silane coupling agent layer formed with a silane adhesion amount of ² .

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

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

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

(5) The surface-treated copper foil, wherein 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 a rust-proof layer containing Cr.

(7) According to the surface-treated copper foil, wherein, the silane coupling agent layer is selected from epoxy silane, amino silane, vinyl silane, methacrylic silane, acrylic silane, styrene-based It consists of at least one type of silane, ureide-based silane, mercapto-based silane, sulfide-based silane, and isocyanate-based silane.

(8) A copper-clad laminate manufactured using the above-mentioned 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 roughened layer side of a surface-treated copper foil, the surface-treated copper foil being formed by providing the roughened layer on a copper foil substrate, characterized in that , in a section perpendicular to the surface of the copper foil substrate, the interface length (Da') measured along the interface between the roughened layer and the insulating substrate is relative to the creepage length measured along the surface of the copper foil substrate The ratio (Da'/Db) of (Db) is in the range of 1.05 to 4.00, the average height difference (H') of the unevenness on the interface is in the range of 0.2 to 1.3 μm, and the roughened layer and the A silane coupling agent layer having a silane adhesion amount of 0.0003 to 0.0300 mg/dm ² is provided between the insulating substrates directly or via an intermediate layer.

(10) The copper-clad laminate, wherein 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 of the copper foil base.

Invention effect

According to the present invention, it is possible to provide a surface-treated copper foil having high reflow heat resistance and transmission characteristics while ensuring sufficient adhesion to an insulating substrate whose relative permittivity and dielectric loss tangent Low and excellent dielectric properties, it can cope with the high-performance and high-functionality of high-frequency information communication equipment that supports high-frequency transmission and processing of large-capacity information. Moreover, this invention can provide the copper clad laminated board manufactured using this surface-treated copper foil.

Description of drawings

(a) of FIG. 1 is a cross-sectional view showing the state of the roughened layer having the constricted shape of the present invention. The constricted shape refers to the shape shown in FIG. 1 , that is, the width of the root of the roughened particle is narrower than the maximum width of the roughened particle, so that the root of the roughened particle has a recess. (b) of FIG. 1 is a sectional view showing the state of a conventional roughened layer.

FIG. 2 is a cross-sectional view schematically showing the average height difference H of the unevenness constituting the uneven surface constituting the roughened layer.

Fig. 3 is a cross-sectional view schematically showing the creeping length Da on the uneven surface of the roughened layer shown in Fig. 1 .

(a) of FIG. 4 is a cross-sectional view showing a baseline BL1 for measuring the average height difference H of the unevenness constituting the roughened surface constituting the roughened layer. (b) of FIG. 4 is a sectional view similarly showing the base line BL2.

FIG. 5 is a cross-sectional view schematically showing air bubbles present at the interface between the roughened layer and the insulating substrate.

Detailed ways

Hereinafter, embodiment of the surface-treated copper foil according to the present invention will be described with reference to the drawings. (a) of FIG. 1 shows a cross-sectional structure when a roughened layer is formed on the surface of 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 roughened layer 120, and a silane coupling agent layer (not shown). That is, in the present invention, those who form roughened layer 120 on copper foil 110 as surface treatment and further form silane coupling agent layer (not shown) as surface treatment are referred to as surface-treated copper foil.

Copper foil 110 can be appropriately selected from electrolytic copper foil, electrolytic copper alloy foil, rolled copper foil, or rolled copper alloy foil according to applications and the like.

The roughened layer 120 is provided by roughening the copper foil base 110 , and has roughly granular fine irregularities formed on the surface. In this roughening treatment, copper electrolysis is performed at a current density exceeding the limiting current density while hydrogen gas is generated to form a so-called burnt plating state, whereby granular electrolytic deposits are formed and micron-order fine unevenness is formed. surface. 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 means this granular electrodeposited material.

Moreover, in the present invention, in a section perpendicular to the copper foil base surface, the creepage length Da measured along the uneven surface of the roughened layer 120 is relative to the creepage length Da measured along the copper foil base surface The (line length) ratio Da/Db of Db is 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 also be in the range of 1.05 to 1.60.

If the wire length ratio Da/Db is less than 1.05, reflow heat resistance may be reduced and satisfactory performance may not be obtained. If the line length ratio Da/Db exceeds 4.00, the unevenness of the surface will increase excessively, so the transmission loss will increase due to the skin effect and the transmission characteristics will deteriorate, so the line length ratio Da/Db is set at 1.05 to 4.00 range. It should be noted that the method of measuring the line length ratio Da/Db will be described below.

The present inventors made an effort to investigate the reason why the line length ratio Da/Db affects the reflow heat resistance, and as a result obtained the following new knowledge. First, a method of preparing a test piece for a reflow heat resistance test will be described. An insulating substrate (base material) obtained by laminating copper foils on both surfaces was used as a core layer. The core layer is etched with a copper(II) chloride solution or the like to dissolve and remove all the copper foil. Next, prepreg layers made of an insulating material and copper foil were laminated on both surfaces of the insulating substrate (base material) remaining after the etching of the core layer 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 replicated at the interface where the insulating substrate (base material) of the core layer was in contact with the prepreg layer. And it was confirmed that in the reflow heat resistance test, since the sample (test piece) was exposed to a high temperature of about 260°C, the low molecular weight components in the insulating substrate (substrate) would volatilize, and the volatilized gas would accumulate between the insulating substrate and the pre-heated substrate. The area where the adhesion between the impregnation layers is weak becomes the cause of delamination. Therefore, it is generally considered that if the line length ratio Da/Db is less than 1.05, the area copied by etching will be reduced, and as a result, the area where the insulating substrate (base material) contacts the prepreg layer will decrease, resulting in two problems. In the area where the adhesion between the layers is low, the gas volatilized from the substrate during heating will accumulate in this area between the layers, and peeling will easily occur.

In the present invention, as a result of diligent research, it has been found that by controlling the line length ratio Da/Db and the average height difference H of the concavo-convex within an appropriate range, a roughened shape with a constricted shape can be obtained, thereby being different from that used in the known examples. Compared with copper foil whose surface area is controlled, the heat resistance is significantly improved. That is, if Da/Db is increased within the range of the average height difference H of the concavities and convexities of this invention so as not to degrade the transmission characteristics, the profile length of the roughened layer becomes longer, and as a result, a roughened layer with a large number of constricted shapes can be obtained. shape. By increasing the number of constricted shapes, a strong anchoring effect is exhibited although the roughness is fine, and the adhesiveness between the copper foil and the insulating substrate (resin substrate) is enhanced, and the heat resistance is improved. Therefore, within the claimed range of the present application, by controlling Da/Db and the average height difference H, the heat resistance can be significantly improved compared with the known example while maintaining high transmission characteristics.

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 there are (a) roughening of the constricted shape 11 and (b) roughening of the non-constricted shape, when the surface area is measured theoretically using a laser microscope, Since the height is measured by projecting laser light from the vertical direction of the copper foil, it is difficult to measure the difference between the presence or absence of the constriction shape of FIG. 1( a ) and FIG. 1( b ). That is, although the shape of the surface directly irradiated by the laser can be measured, such as a necked part, when the laser is projected from the vertical direction, it will become a shadow, so it is impossible to measure the shape of the part that is not directly irradiated by the laser.

Therefore, as shown in the embodiment of Patent Document 4, when the surface area ratio is measured with a laser microscope, the presence or absence of a constricted shape cannot be reflected in the measured value, so the surface area ratio measured by the laser microscope is used to control the copper foil. The surface shape is not suitable for this case. In addition, the aspect ratio shown in Patent Document 4 only represents the ratio of the "height" to the "width" of the roughened particles, and does not consider the constricted shape at all.

Furthermore, when an insulating substrate is brought into close contact with the roughened layer side of the copper foil having the roughened layer obtained in the above-described embodiment to form a copper-clad laminate, there is a gap along the interface between the roughened layer and the insulating substrate. On the other hand, the measured interface length (Da') tends to be slightly reduced due to pressurized close contact with the insulating substrate. Therefore, it is necessary to maintain the line length ratio in the above-mentioned range even after the insulating substrate is closely bonded, and, on a section perpendicular to the surface of the copper foil base after the insulating substrate is bonded, by making the roughened layer The ratio (Da'/Db) of the interface length (Da') measured at the interface with the insulating substrate 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, and it is possible to obtain The same effect as in the case of (Da/Db) described above.

Therefore, in the present invention, the average height difference (corresponding to the average height of the roughened particles) H of the unevenness of the uneven surface of the copper foil is in the range of 0.2 to 1.3 μm. When the average height difference H of the uneven|corrugated surface is less than 0.2 micrometer, since anchor effect is weak, sufficient adhesiveness of copper foil and an insulating substrate cannot be acquired. In addition, when the average height difference H of the unevenness on the uneven surface exceeds 1.3 μm, the surface unevenness becomes too large, and the transmission loss increases due to the skin effect. Furthermore, the average height difference H of the concave-convex surface may be in the range of 0.2-0.8 μm, and the average height difference H of the concave-convex surface may also be in the range of 0.2-0.3 μm.

Furthermore, if an insulating substrate is brought into close contact with the roughened layer side of the copper foil having the roughened layer obtained in the above embodiment to form a copper-clad laminate, the unevenness H of the roughened layer will be caused by Tendency to slightly decrease due to pressurized close contact with the insulating substrate. Therefore, it is also necessary to maintain the average height of the unevenness in the range after the insulating substrate is closely bonded, and the average height difference of the unevenness of the uneven surface (equivalent to The average height of the roughened particles) H′ is in the range of 0.2 to 1.3 μm, and the same effect as in the case of H can be obtained.

The inventors of the present invention investigated the method of controlling Da/Db in the range of an appropriate uneven average height difference (H), and found that in the roughening methods of Document 6 and Document 7, the concentration of the chelating agent was high, so the copper The formation of a large number of fine roughened particles on the surface of the foil will excessively increase Da/Db, resulting in increased transmission loss. The inventors of the present invention worked hard to study the countermeasures of this problem, and as a result, it was found that by making the concentration of the chelating agent lower than in the past, the particles will become an appropriate size, and Da/Db can be controlled in the most suitable range. Improves transmission loss characteristics while maintaining high adhesion and heat resistance. Specifically, the concentration of the chelating agent added to the plating bath can be made to be in the range of 0.1 to 5 g/L.

As the mechanism of the reaction, it is presumed that by using a low concentration of the chelating agent, the overvoltage during electrolysis is reduced compared to the high concentration condition, thereby reducing the nucleation frequency, so that the effect of miniaturization can be appropriately suppressed to form a suitable size. Coarse particles. In addition, it is generally believed that when the chelating agent is at a low concentration, because the number of chelate molecules in the bath is small, most of the coordinated metal ions (Cu, etc.) in the chelate are uncoordinated with the chelate. The metal ions at the position are mixed together in the bath, and the difference in the coordination state of the chelate causes particles with different precipitation modes to form at the same time, thus becoming a complex particle shape with a necked shape, so that in the appropriate Da/Db range It can also combine high heat resistance and adhesiveness. In addition, when the concentration of the chelating agent is low, the growth in the height direction of the roughened particles is appropriately suppressed, and the average height difference H of the unevenness is set in an appropriate range. According to the precipitation mode in the state where most of the coordinated metal ions (Cu, etc.) of the chelate and the uncoordinated metal ions of the chelate are mixed together in the bath, the orientation of the precipitation is random, so it is highly Growth in the direction is suppressed.

In addition, the inventors of the present invention have found that a method of adding two types of chelating agents to a roughening treatment bath is also effective as a method of appropriately controlling Da/Db. It is speculated that by adding two kinds of chelating agents, metals with different coordination states of the chelates are electrolyzed at the same time, and particles with different shapes are precipitated at the same time, so that the shape of the coarsened particles becomes complicated, and the anchoring effect is easily exhibited.

As another method of appropriately managing Da/Db, it is also effective to form roughened particles at a current density of 70 to 90 A/dm ² , which has not been used in the past due to problems such as powder falling. However, if the treatment time is long, the particles will grow excessively in the vertical direction and the powder will easily fall off, so the treatment time needs to be shortened. When the current density is high, the amount of hydrogen gas generated on the cathode increases. It is speculated that before the hydrogen gas escapes from the cathode and enters the liquid, it is a spot that cannot be plated, so the time point of the coarsening deposition becomes discontinuous, and as a result, a surface shape with a suitable number of unevennesses can be obtained.

Furthermore, in the present invention, a silane coupling agent layer formed with a silane adhesion amount of 0.0003 to 0.0300 mg/dm ² is provided on the rough-surfaced layer 120 directly or via an intermediate layer. If the silane adhesion amount of the silane coupling agent constituting the silane coupling agent layer is less than 0.0003 mg/dm ² , reflow heat resistance will decrease. Moreover, when the said adhesion amount exceeds 0.0300 mg/dm ^<2> , the silane coupling agent layer will become too thick, and adhesion strength will fall conversely. It should be noted that the silane adhesion amount of the silane coupling agent constituting the silane coupling agent layer may be 0.0005 to 0.0120 mg/dm ² .

Furthermore, as the formation method of the silane coupling agent layer, for example, the following method can be enumerated: directly or indirectly coating a silane coupling agent solution through an intermediate layer on the uneven surface of the roughened layer 120, and then air-drying Or formed by heating and drying. Regarding the drying of the coated coupling agent layer, the effect of the present invention can be fully exhibited as long as the moisture evaporates, but from the viewpoint of accelerating the reaction between the silane coupling agent and the copper foil, it is preferably at a temperature of 50 to 180°C Under heat drying.

Preferably, the silane coupling agent layer contains 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 Any one or more of silanes and isocyanate-based silanes.

It is preferable that the concave-convex surface of the present invention has a large number of constricted shapes. Although a large number of necked shapes will cause coarsening and fineness, it can exhibit a strong anchoring effect to enhance the adhesion between the copper foil and the insulating substrate and improve the heat resistance. To form a concave-convex surface with a large number of constricted shapes, as described above, the roughened layer can be made The profile length of the becomes longer, resulting in a roughened shape with a lot of necked-in shape.

In addition, in the present invention, when laminating the copper foil and the insulating substrate, the number of bubbles at the interface between the roughened layer and the insulating substrate is preferably 2 or less over the width of the substrate (for example, 2.54 μm). In this case, in the process of investigating the factors affecting the reflow heat resistance, it was found that, in addition to the above-mentioned line length ratio Da/Db and the average height difference H, the interface between the roughened layer of the copper foil and the insulating substrate in the reflow test piece The number of bubbles also has a big impact. Here, the bubbles in this case refer to a region where the insulating substrate is not filled at the interface between the roughened layer and the insulating substrate, and the size thereof is 1.0 μm or less in terms of the major axis. If the number of air bubbles at the interface between the roughened layer of the copper foil and the insulating substrate is large, the gas volatilized from the insulating substrate will concentrate in the air bubbles during heating in the reflow test, and the gas pressure in the air bubbles will increase. , causing delamination to easily occur.

Therefore, the inventors of the present invention tried to investigate a method for reducing the number of bubbles at the interface between the roughened layer and the substrate, and as a result, it was found that appropriately controlling the treatment conditions of the silane coupling agent is an effective method. Specifically, first, there is a method of adding alcohol to an aqueous silane coupling agent solution. As alcohol, methanol, ethanol, isopropanol, n-propanol, etc. are mentioned. By adding alcohol, the dispersibility of the silane molecules in the solution becomes better, and the silane coupling agent can be uniformly processed on the roughened layer of the copper foil, so the wettability to the resin is improved. Furthermore, it is presumed that when the substrate and the copper foil are bonded at high temperature, the molten resin sufficiently infiltrates the roughened layer to improve the fillability, thereby reducing the number of air bubbles at the interface between the roughened layer and the substrate. In addition, it is also effective to extend the time from the treatment of the copper foil with the silane aqueous solution to drying with warm air. It is speculated that by extending the time from the treatment with the silane aqueous solution to the drying with warm air, the silane molecules can be regularly oriented on the surface of the roughened layer of the copper foil and the wettability to the resin can be improved. As a result, the The number of air bubbles at the interface between the roughened layer and the insulating substrate is reduced. For example, in the case of the silane treatment described 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 tends to increase.

The number of bubbles at the interface between the roughened layer of the copper foil and the insulating substrate should only be 2 or less on the line of 2.54 μm in the width direction of the substrate. The number of air bubbles may be 1 or less or 0 on this line. If the number of air bubbles at the interface between the roughened layer of the copper foil and the insulating substrate is 3 or more on this line, the gas generated from the insulating substrate during the reflow test may concentrate on the air bubbles and cause interphase delamination to occur easily. And the reflow heat resistance (between the copper foil and the prepreg layer) tends to decrease.

As another embodiment, between the roughened layer 120 and the silane coupling agent layer, there may be at least 1 selected from the base layer containing Ni, the heat-resistant treatment layer containing Zn, and the rust-proof treatment layer containing Cr. layer middle layer.

If, for example, copper (Cu) in the copper foil substrate 110 or the rough-surfaced layer 120 diffuses to the insulating substrate side to cause copper damage and reduce the adhesion, it is preferable to mix the roughened layer 120 with a silane coupling agent. An underlayer containing nickel (Ni) is formed between the layers. The Ni-containing underlayer contains at least one of nickel (Ni), nickel (Ni)-phosphorus (P), and nickel (Ni)-zinc (Zn). Among these, nickel-phosphorus is preferable from the viewpoint of being able to suppress nickel residue during copper foil etching during circuit wiring formation.

It is preferable to form a heat-resistant treatment layer containing zinc (Zn) when the heat resistance needs to be further improved. It is preferred that the heat-resistant treatment layer is made of, for example, zinc or an alloy containing zinc, namely selected from zinc (Zn)-tin (Sn), zinc (Zn)-nickel (Ni), zinc (Zn)-cobalt (Co), zinc ( Zn)-copper (Cu), zinc (Zn)-chromium (Cr), and zinc (Zn)-vanadium (V) containing at least one zinc-containing alloy. Among them, zinc-vanadium is particularly preferable from the viewpoint of suppressing undercut during etching during circuit wiring formation. In addition, the "heat resistance" mentioned here refers to the property that the adhesion strength between the surface-treated copper foil and the insulating substrate is not easily reduced after the insulating substrate is laminated on the surface-treated copper foil and heated to cure the resin. for reflow heat resistance characteristics.

A rust preventive treatment layer containing Cr may also be formed when further improvement of corrosion resistance is required. Examples of the antirust treatment layer include a chromium layer formed by chrome plating and a chromate layer formed by chromate treatment.

When the above-mentioned three layers, that is, the base layer, the heat-resistant treatment layer, and the anti-rust treatment layer are all formed, they may be formed in this order on the roughened layer, or only the three layers may be formed according to the characteristics as the use or purpose. Either layer or any two layers.

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

Insulating substrates for copper-clad laminates can use resin compositions selected from thermosetting polyphenylene ether resins, thermosetting polyphenylene ether resins containing polystyrene-based polymers, polymers or copolymers containing triallyl cyanurate , Epoxy resin composition modified by methacrylic acid or acrylic acid, phenolic addition butadiene polymer, diallyl phthalate resin, divinylbenzene resin, multifunctional methacryl resin, Insulating resins such as unsaturated polyester resins, polybutadiene resins, styrene-butadiene, cross-linked polymers of styrene-butadiene and styrene-butadiene, etc.

When manufacturing a copper-clad laminated board, what is necessary is just to manufacture by heat-compression-bonding the surface-treated copper foil which has a silane coupling agent layer, and an insulating substrate, and bringing both into close contact. Furthermore, the copper-clad laminate made by coating the silane coupling agent on the insulating substrate and making the insulating substrate and the copper foil with an anti-rust treatment layer on the outermost surface by heating and pressing has the same effect as the present invention. .

〔Production of surface-treated copper foil〕

(1) Step of forming roughened layer

A roughened layer having an uneven surface is formed on copper foil by electrolysis of roughened particles.

In addition to controlling the line length ratio Da/Db, it is preferable to further (i) appropriately control the size of the roughened particles and (ii) facilitate simultaneous deposition of roughened particles having different shapes.

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

Here, the concentration of the chelating agent added to the electroplating bath for roughening treatment is preferably 0.1 to 5 g/L. Examples of the chelating agent include chelating agents such as DL-malic acid, sodium EDTA solution, sodium gluconate, pentasodium diethylenetriaminepentaacetic acid (DTPA), and the like.

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

In addition, in order to reduce the number of air bubbles in the interface between the roughened layer and the insulating substrate to 2 or less on the line of 2.54 μm in the width direction of the copper foil substrate, it is possible to improve the wettability of the roughened layer to the surface of the insulating substrate, etc. method. Therefore, there are, for example, (i) performing the silane coupling treatment so that the silane coupling agent layer is uniformly formed on the roughened layer, (ii) orienting the silane molecules in the silane coupling agent layer regularly. A method such as silane coupling treatment is performed. As a specific example of (i), there is a method of adding alcohol to an aqueous solution of a silane coupling agent; Before the time extension method etc.

(2) Formation process of base layer

An underlayer containing Ni is formed on the rough-surfaced layer as needed.

(3) Formation process of heat-resistant treatment layer

A heat-resistant treatment layer containing Zn is formed on the roughened layer or on the base layer as needed.

(4) Formation process of anti-rust treatment layer

If necessary, the copper foil on which the layer is formed is immersed in an aqueous solution containing a Cr compound with a pH value lower than 3.5, and a chromium plating treatment is performed at a current density of 0.3 A/dm ² or more, whereby on the roughened layer, An anti-rust treatment layer is formed on the base layer or on the heat-resistant treatment layer.

(5) Formation process of silane coupling agent layer

A silane coupling agent layer is formed on the roughened layer, on the base layer, on the heat-resistant treatment layer, or on the antirust treatment layer.

〔Manufacture of copper-clad laminates〕

The copper-clad laminate of this embodiment is manufactured through the following steps.

(1) Production of surface-treated copper foil

Surface-treated copper foil was produced in accordance with (1) to (5) above.

(2) Manufacturing (lamination) process of copper-clad laminates

Lay the surface-treated copper foil and the insulating substrate prepared above together, make the surface of the silane coupling agent layer constituting the surface-treated copper foil face the bonding surface of the insulating substrate, and then heat and press to make the two adhere , thereby manufacturing a copper-clad laminate.

In addition, the said content shows the example of embodiment of this invention only, Various changes are possible in the range which does not deviate from the summary of this invention.

Example

(Example 1)

The surface-treated copper foil was prepared as a non-roughened (surface roughness Rz about 0.8 μm) copper foil substrate with a thickness of 18 μm under the following conditions.

(1) Formation of roughened layer

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

(rough surface plating treatment 2)

Copper sulfate: 13 to 72g/L in terms of copper concentration

Sulfuric acid concentration: 26 to 133g/L

Liquid temperature: 18 to 67°C

Current density: 3 to 67A/dm ²

Processing time: 1 second to 1 minute 55 seconds

(2) Formation of base layer containing Ni

After forming a roughened layer on the surface of the copper foil base, electroplating was performed on the roughened layer under the nickel plating conditions shown below to form an underlayer (Ni deposition amount: 0.06 mg/dm ² ).

<Nickel Plating Conditions>

Nickel sulfate: 5.0g/L based on nickel metal

Ammonium persulfate 40.0g/L

Boric acid 28.5g/L

Current density 1.5A/dm ²

pH 3.8

Temperature 28.5°C

Time 1 second to 2 minutes

(3) Formation of Zn-containing heat-resistant treatment layer

After forming the base layer, electroplating was performed on the base layer under the galvanizing conditions shown below to form a heat-resistant treatment layer (Zn deposition amount: 0.05 mg/dm ² ).

<Galvanizing condition>

Zinc sulfate heptahydrate 1 to 30g/L

Sodium hydroxide 10 to 300g/L

Current density 0.1 to 10A/dm ²

Temperature 5 to 60°C

Time 1 second to 2 minutes

(4) Formation of antirust treatment layer containing Cr

After the heat-resistant treatment layer was formed, the heat-resistant treatment layer was treated under the following chromium plating treatment conditions to form a rust-proof treatment layer (amount of deposited Cr: 0.02 mg/dm ² ).

<Chrome plating condition>

(chrome bath)

Chromic anhydride CrO ₃ 2.5g/L

pH 2.5

Current density 0.5A/dm ²

Temperature 15 to 45°C

Time 1 second to 2 minutes

(5) Formation of silane coupling agent layer

After the antirust treatment layer was formed, methanol or ethanol was added to the silane coupling agent aqueous solution under the conditions shown in Table 2 on the antirust treatment layer, and the treatment solution adjusted to a predetermined pH value was applied. Thereafter, it was stored for a predetermined time, and then dried with warm air to form a silane coupling agent layer having a silane adhesion amount shown in Table 3. In addition, the underlined numerical value in Table 3 represents the numerical value outside the suitable range of this invention.

[Table 2]

(Example 2 to Example 18)

The surface roughening plating process 1 was performed based on the content of Table 1, and the silane coupling agent process was performed based on the content of Table 2, and it processed similarly to Example 1 except having performed it.

(Comparative Example 1 to Comparative Example 7 and Comparative Example 9 to Comparative Example 14)

The surface roughening plating process 1 was performed based on the content of Table 1, and the silane coupling agent process was performed based on the content of Table 2, and it processed similarly to Example 1 except having performed it.

[Comparative Example 8]

Use a roll-shaped liquid crystal polymer film (Vecster (registered trademark) CT-Z manufactured by Kuraray Co., Ltd.), immerse in a potassium hydroxide solution (liquid temperature 80° C.) for 10 minutes, and then etch to roughen the surface. processing. Next, an electroless copper plating layer was formed on the roughened thermoplastic resin film through the following electroless copper plating bath.

<Electroless Copper Plating Bath>

Copper sulfate pentahydrate (based on copper content) 19g/L

HEEDTA (chelating agent) 50g/L

Sodium phosphonite (reducing agent) 30g/L

Sodium chloride 20g/L

Disodium hydrogen phosphate 15g/L

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

Characteristic evaluation of test piece

Table 3 shows the results of various measurements and evaluations for each test piece.

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

In the section perpendicular to the copper foil substrate surface (plane direction P) shown by the double arrow in FIG. 3, the creeping length Da measured along the uneven surface 120 of the roughened layer is relative to The ratio Da/Db of the length Db along the surface measured on the surface of the substrate 110 is defined as the line length ratio. If the uneven surface of the roughened layer on the cross section has more or larger unevenness, the line length ratio will increase.

Each test piece was processed by an ion milling device (manufactured by Hitachi: IM4000), and the cross-section of each treated test piece was observed using a scanning electron microscope (SEM: manufactured by Hitachi: SU8020), and then according to the following order to determine the line length ratio Da/Db. The calculation is based on an observed image enlarged at a magnification of 10,000 times (the actual width of the field of view in the image in this case is 12.7 μm). The observation image of the SEM was analyzed using image analysis software Winroof (Mitani Corporation), thereby measuring the creepage length Da on the uneven surface of the roughened layer shown by the thick line in FIG. 3 . In addition, other image analysis software can also be used to perform the measurement in the same manner. Regarding the magnification of the SEM, it is preferable that the width of the SEM image is in the range of 5 to 15 μm. In this case, Dan/Dbn (n=1 to 10) was measured at 10 visual fields, and the average value thereof 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 in this case is 63.5 μm), and at any position, the extension direction of the concave-convex surface is consistent with the horizontal direction of the screen within the error range of ±1°. Next, the observation magnification is enlarged to 10,000 times (the actual width of the field of view in the image of this case is 12.7 μm), and the bottom position of the first concave portion is set as point A. The bottom position of the first concave portion is an arbitrary position in the SEM image. Shows the position of the lowest point in the bumps that form the bumpy surface. Then, among the remaining concave portions other than the first concave portion and the concave portion adjacent to the first concave portion, the bottom position of the second concave portion whose bottom position is the lowest point position is defined as point B. And let the straight line which connects point A and point B be base line BL1 ((a) of FIG. 4). Thereafter, in the SEM image enlarged to 50,000 times (the actual width of the field of view in the image of this case is 2.54 μm), draw the baseline BL2 parallel to the baseline BL1, which passes through the bottom position of the third concave portion, and the bottom of the third concave portion The bottom position is the position of the lowest point among the concavities and convexities that form the concavo-convex surface at any position, and the distance from the base line BL2 to the apex of the convex part that is farthest in the vertical direction is set as the height difference H and is measured ((b of FIG. 4 )). In the present embodiment, the height difference is measured at five fields of view, and the average value thereof is taken as the average height difference H.

(2) The number of air 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 rough-surfaced layer 43 and the insulating substrate 42 was measured in the following procedure. First, use a press machine to press the insulating substrate 42 (prepreg layer) and copper foil 43 under the standard pressing conditions recommended by the insulating substrate manufacturer to produce a laminate (in this case, Panasonic Corporation MEGTRON6:R -5670 was used as the insulating substrate 42, and laminated under the following bonding conditions: bonding temperature of 200°C, bonding pressure of 35kgf/cm ² , and bonding time of 160 minutes). Next, use the ion milling device to process the laminated body, and use the scanning electron microscope to magnify the cross-section of the processed laminated body to 50,000 times (the actual width of the field of view in the image in this case is 2.54 μm), And the interface of the rough-surfaced layer 43 of a laminated body, and the insulating substrate 42 was observed. As shown in FIG. 5 , the number of air bubbles 41 present at the interface between the rough-surfaced layer 43 and the insulating substrate 42 on a line having a width of 2.54 μm was measured at 10 places, and the average value of the number of air bubbles at 10 places was taken as The number Vi of bubbles at the interface between the rough-surfaced layer 43 and the insulating substrate 42 . The bubbles in this case refer to regions where the insulating substrate is not filled at the interface between the roughened layer and the insulating substrate, and the size thereof is 1.0 μm or less in terms of the major axis.

(3) Determination of silane adhesion amount

Analysis was performed with a fluorescent X-ray analyzer (ZSX Primus manufactured by RIGAKU Co., Ltd., analysis diameter: Φ35 mm).

(4) Measurement of the line length ratio Da'/Db after the insulating substrate is closely bonded and the average height difference H' of the uneven surface

After bonding each copper foil to an insulating substrate, the line length ratio Da'/Db and the average height difference H' of the uneven surface were measured in the same manner as the measurement of Da/Db and H described above.

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

After bonding each copper foil to an insulating substrate, a sample for transmission characteristic measurement was produced, and the transmission loss in the high frequency band was measured. A commercially available polyphenylene ether-based insulating substrate (MEGTRON 6 manufactured by Panasonic Corporation) was used as the insulating substrate. The substrate for measurement of transmission loss adopts a stripline structure, the conductor length is 400mm, the conductor thickness is 18μm, the conductor width is adjusted to 0.14mm, the overall thickness is adjusted to 0.31mm, and the characteristic impedance is adjusted to 50Ω. For evaluation, transmission loss at 10 GHz and 40 GHz was measured using a vector network analyzer E8363B (manufactured by KEYSIGHT TECHNOLOGIES). The transmission loss measured when the conductor length is 400mm is converted into the value when the conductor length is 1000mm, and this value is taken as the measurement result of transmission loss, and the unit is dB/m. Specifically, the value obtained by multiplying the value of the transmission loss measured when the conductor length was 400 mm by 2.5 was used as the measured value of the transmission loss. The results are shown in Table 3. Regarding the transmission characteristics, the case where the transmission loss was less than 19.5 dB/m at 10 GHz was considered acceptable, and the case where the transmission loss was less than 66.0 dB/m at 40 GHz was considered acceptable.

(6) Adhesive strength

The adhesion strength between the surface-treated copper foil and the insulating substrate was measured. A commercially available polyphenylene ether substrate was used as the insulating substrate. The curing conditions of the insulating (resin) substrate were set at 210° C. for 1 hour. The copper foil was bonded to the insulating substrate using a universal material testing machine (TENSILON, manufactured by A&D Co., Ltd.), and then the test piece was etched into a circuit wiring with a width of 10 mm, and the insulating side was fixed to the stainless steel plate with double-sided tape, and then The circuit wiring was peeled at a speed of 50 mm/min in a 90-degree direction to obtain the adhesion strength. Regarding the initial stage adhesiveness, the case where the peeling strength was 0.4 kN/m or more was regarded as acceptable, and the case where the peeling strength was less than 0.4 kN/m was regarded as unacceptable.

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

First, the preparation method of the test piece of the reflow heat resistance test (between copper foil and a prepreg layer) is demonstrated. Copper foils were laminated on both sides to produce reflow test pieces (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) is 100mm×100mm. Next, the prepared test piece was passed into a reflow furnace, and passed 10 times under the heating conditions of a top temperature of 260° C. and a time of 10 seconds. After heating under the above-mentioned conditions, those who swelled observed the section of the swollen region with a microscope to check whether there was delamination between the copper foil and the prepreg layer. The case where delamination did not occur between the copper foil and the prepreg layer was judged as "○ (pass)", and the case where delamination occurred at one point between the copper foil and the prepreg layer was judged as "Δ (pass) ”, and the case where delamination occurred at two or more places between the copper foil and the prepreg layer was judged as “× (unacceptable)”. In addition, the content of the reflow test is based on JIS C 60068-2-58.

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

Next, the preparation 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 laminated with copper foil on both sides was used as a core layer. The core layer is etched with a copper(II) chloride solution or the like to dissolve all the copper foil. A reflow test piece was produced by laminating a prepreg layer and copper foil as an insulating substrate 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) is 100mm×100mm.

Next, the prepared test piece was passed into a reflow furnace, and passed 10 times under the heating conditions of a top temperature of 260° C. and a time of 10 seconds. After heating under the above conditions, the case where delamination did not occur between the core layer and the prepreg layer was judged as "○ (pass)", and delamination occurred at one point between the core layer and the prepreg layer The test result was judged as "Δ (pass)", and the case where delamination occurred at two or more places between the core layer and the prepreg layer was judged as "x (failure)". In addition, the content of the reflow test is based on JIS C 60068-2-58.

As is clear from Table 3, Examples 1 to 18 are acceptable grades in all performances of adhesion to an insulating substrate, transport characteristics, and reflow heat resistance. On the other hand, in Comparative Example 1, the line length ratios Da/Db and Da'/Db are small, and the average height differences H and H' of the uneven surface are also low, so the adhesion strength is low and the reflow heat resistance is also poor. In Comparative Example 2, the line length ratios Da/Db and Da'/Db are large, and the average height differences H and H' of the uneven surface are also high, so the transmission loss is large and the transmission characteristics are poor. In Comparative Example 3, the line length ratios Da/Db and Da/Db' were small, and the amount of silane attached was also small, so the reflow heat resistance was poor. In Comparative Example 4, the line length ratios Da/Db and Da'/Db were small, the average height differences H and H' of the uneven surface were low, and the amount of silane adhered was large, so the adhesion strength was low. Regarding Comparative Examples 5 to 7, the line length ratios Da/Db and Da/Db' are large, the average height differences H and H' are large, and the number of bubbles at the interface between the roughened layer and the insulating substrate is large, so the reflow resistance Poor heat. In Comparative Example 8, the line length ratios Da/Db and Da'/Db were small, and the average height difference H of the unevenness on the uneven surface was low, so the adhesion strength was low. Regarding Comparative Examples 9 to 14, the line length ratios Da/Db and Da'/Db are large, and especially in Comparative Examples 9 to 11, the average height difference H and H' of the uneven surface are also high, so The transmission loss is large and the transmission characteristics are poor. Industrial availability

According to the present invention, it is possible to provide a surface-treated copper foil that ensures sufficient adhesion to an insulating substrate and has both high reflow heat resistance and transmission characteristics, and a copper-clad laminate manufactured using the surface-treated copper foil, The insulating substrate has excellent dielectric properties due to its low relative permittivity and dielectric loss tangent, and can cope with high-performance and high-functioning information communication equipment that supports high-frequency transmission and processing of large-capacity information.

Explanation of reference signs:

11 neck shape

110 copper foil substrate

120 roughening layers

Da is the creepage length measured along the uneven surface of the roughened layer

Db is the creepage length measured along the surface of the copper foil substrate

P Width of substrate

41 bubbles

42 insulating substrate

43 roughening layer.

Claims (10)

1. A surface-treated copper foil, which is formed by setting a roughened layer on a copper foil substrate, is characterized in that, The roughened layer has a plurality of roughened particles, and the surface of the roughened layer is constituted as a concave-convex surface. In a section perpendicular to the surface of the copper foil substrate, along the concave-convex surface of the roughened layer, The ratio Da/Db of the measured creepage length Da to the creepage length Db measured along the surface of the copper foil base is in the range of 1.05 to 4.00, and the average height difference H of the uneven surface is in the range of 0.2 to 1.3 μm , and further have a silane coupling agent layer formed with a silane adhesion amount of 0.0003 to 0.0300 mg/dm ² directly or via an intermediate layer on the roughened layer. 2. The surface-treated copper foil according to claim 1, characterized in that, The concave-convex surface has a constricted shape. 3. The surface-treated copper foil according to claim 1 or 2, characterized in that, The ratio Da/Db of the creeping surface length is in the range of 1.05 to 3.20 times, 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 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, which is a direction perpendicular to the production direction of the copper foil. 4. The surface-treated copper foil according to any one of claims 1 to 3, characterized in that, The ratio Da/Db of the creeping surface length is in the range of 1.05 to 1.60 times, the average height difference H of the unevenness is in the range of 0.2 to 0.3 μm, and when the copper foil and the insulating substrate are laminated, the copper foil base The number of bubbles at the interface between the rough-surfaced layer and the insulating substrate is 1 or less on a line of 2.54 μm in the width direction of . 5. The surface-treated copper foil according to any one of claims 1 to 4, characterized in that, 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 according to any one of claims 1 to 5, characterized in that, The intermediate layer is composed of at least one layer selected from the base layer containing Ni, the heat-resistant treatment layer containing Zn, and the antirust treatment layer containing Cr. 7. The surface-treated copper foil according to any one of claims 1 to 6, characterized in that, The silane coupling agent layer is selected from epoxy silane, amino silane, vinyl silane, methacrylic silane, acrylic silane, styryl silane, ureide silane, mercapto silane, vulcanization Consisting of at least one of material-based silanes and isocyanate-based silanes. 8. A copper clad laminate, characterized in that, The surface on the roughened layer side of the surface-treated copper foil according to any one of claims 1 to 7 has an insulating substrate. 9. A copper-clad laminate, which has an insulating substrate on the roughened layer side of a surface-treated copper foil, and the surface-treated copper foil is formed by providing the roughened layer on a copper foil substrate, characterized in that , In a section perpendicular to the surface of the copper foil substrate, the ratio of the interface length Da' measured along the interface between the roughened layer and the insulating substrate to the creepage length Db measured along the surface of the copper foil substrate Da'/Db is in the range of 1.05 to 4.00 times, the average height difference H' of the unevenness on the interface is in the range of 0.2 to 1.3 μm, and then directly or indirectly between the roughened layer and the insulating substrate A silane coupling agent layer having a silane adhesion amount of 0.0003 to 0.0300 mg/dm ² interposed between the intermediate layer. 10. The copper clad laminate according to claim 9, characterized in that, The number of bubbles at the interface between the rough-surfaced layer and the insulating substrate is 2 or less on a line of 2.54 μm in the width direction of the copper foil base.