TW201800242A - Surface-treated copper foil and copper-clad laminate produced using same - Google Patents

Abstract

The present invention provides: a surface-treated copper foil which achieves a balance at a high level between reflow heat resistance and transmission characteristics, while ensuring sufficient adhesion to an insulating substrate; and the like. A surface-treated copper foil according to the present invention is obtained by providing a surface roughening layer (120) on a copper foil base (110), and is characterized in that: the surface roughening layer (120) has a recessed and projected surface that is formed of roughening particles; in a cross-section that is perpendicular to the copper foil base surface, the ratio of the creepage distance (Da) measured along the recessed and projected surface of the surface roughening layer (120) relative to the creepage distance (Db) measured along the copper foil base surface, namely Da/Db is within the range of 1.05-4.00; the average height difference H between recesses and projections in the recessed and projected surface is within the range of 0.2-1.3 [mu]m; and a silane coupling agent layer having a silane coating amount of 0.0003-0.0300 mg/dm2 is formed on the surface roughening layer (120) directly or with an intermediate layer being interposed therebetween.

Description

Surface-treated copper foil and copper-clad laminated board using the same

The invention relates to a surface-treated copper foil and a copper-clad laminated board made using the same. The surface-treated copper foil can ensure sufficient adhesion to an insulating substrate and has both high reflow heat resistance and transmission characteristics.

In recent years, with the development of high performance and high performance of computers and information communication equipment, and the development of networking, there is a tendency for signals to become increasingly high-frequency to perform high-speed transmission and processing of large-capacity information. This type of information communication equipment uses copper-clad laminates. The copper-clad laminated board is produced by heating and pressing an insulating substrate (resin substrate) and a copper foil. Generally, insulating substrates that constitute copper-clad laminated boards that support high frequencies must use resins with excellent dielectric properties. However, resins with low relative permittivity and dielectric loss tangent tend to: There are few functional groups with high polarity and low adhesion to copper foil.

In addition, it is desirable to reduce the surface roughness of copper foil as a conductive layer used for a copper-clad laminated board that supports high frequencies. The reason why such a low profile of a copper foil is required is that with high frequency, a current flows intensively on the surface portion of the copper foil, so that the larger the surface roughness of the copper foil, the larger the transmission loss. . In order to improve the adhesion of the copper foil constituting the copper-clad laminated board to the insulating substrate, a surface roughening layer having a fine uneven surface (hereinafter referred to as an uneven surface) is generally formed on the copper foil substrate. The uneven surface is made of roughened particles. Is formed by electrodeposition to improve adhesion by physical effect (anchoring effect). If the height difference (surface roughness) of the uneven surface is increased, the adhesion force is increased, but the transmission loss is increased due to the aforementioned reasons. In spite of this, in the current situation, it is preferred to make the surface of the surface roughened layer formed on the copper foil substrate a concavo-convex surface to ensure adhesion and allow a certain degree of increase in transmission loss due to the formation of the concavo-convex surface. However, development of a next-generation high-frequency circuit substrate supporting frequencies above 20 GHz is currently underway, and it is expected that the substrate will further reduce transmission loss compared to the previous one.

In general, in order to reduce transmission loss, it is preferable to use, for example, a surface-treated copper foil after reducing the step (surface roughness) of the surface roughness of the surface-roughened layer, or an unroughened smooth without surface roughening. Copper foil. 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 between the copper foil and the insulating substrate, and the coupling agent layer forms a chemical bond.

When manufacturing the high-frequency circuit board using the above-mentioned copper foil, in addition to the above-mentioned adhesion and transmission characteristics, it has recently been necessary to further consider reflow heat resistance. Here, the "reflow heat resistance" refers to heat resistance in a solder reflow step performed when a high-frequency circuit board is manufactured. The solder reflow step is a method of applying solder by heating the reflow furnace while the paste solder is attached to the contact points of the circuit board wiring and electronic components. In recent years, from the viewpoint of reducing the environmental load, solders used for electrical joints of circuit boards are being made lead-free (Pb). Compared with the previous solder, the lead-free solder has a higher melting point, and when applied to the solder reflow step, the circuit board is exposed to a high temperature, for example, about 260 ° C. Therefore, it is necessary to compare with the previous solder. With high reflow heat resistance. Therefore, in particular, for copper foils used in such applications, it has become a new subject to ensure sufficient adhesion to insulating substrates and to have both high reflow heat resistance and transmission characteristics.

The applicant proposed, for example, Patent Document 1, a method of forming a fine unevenness on the surface of a thermoplastic resin film using a potassium hydroxide solution, and then sequentially performing electroless copper plating and electrolytic copper plating to form a copper layer having fine unevenness. The fine unevenness is caused by the surface shape of the thermoplastic resin film, thereby producing a circuit board that is excellent in transmission characteristics and adhesion, that is, a laminated body covered with metal. However, the applicant further studied the invention described in Patent Document 1 later, and as a result, it was found that the reflow heat resistance may not be sufficiently obtained in some cases, and thus needs to be improved.

In addition, the present applicant also proposed in Patent Document 2 a surface-treated copper foil having a roughened surface having a height of 1 to 5 µm of protrusions formed by roughened particles on at least one side of the electrolytic copper foil. The surface-treated copper foil described in Patent Document 2 has a high height of protrusions and is not intended to improve reflow heat resistance. The silane coupling layer is formed as needed, so it has excellent adhesion to the liquid crystal polymer film. However, since the surface roughness is increased by attaching the roughened particles, there is a tendency that the transmission loss will increase. Therefore, it is inadequate when applied to insulating substrates that support high frequencies above 20 GHz in recent years. In some cases, the reflow heat resistance cannot be fully obtained, and thus needs to be improved.

Furthermore, Patent Document 3 discloses a surface-treated copper foil for a copper-clad laminated board, which is formed by roughening treatment using a copper-cobalt-nickel alloy plating. When such a copper foil is used in a high-frequency circuit board, the contact area between the copper foil and the resin is increased, so 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, no consideration was given to reflow heat resistance.

Patent Document 4 discloses a copper foil that improves the transmission characteristics, adhesion, and heat resistance by roughening copper. When such a copper foil is used, improvement in transmission characteristics can be expected. However, under heating conditions of about 260 ° C. in the reflow test, delamination and peeling occur between the copper foil and the insulating substrate (resin substrate). Unable to exhibit satisfactory characteristics. In Patent Document 5, a surface-treated copper foil with an extremely thin primer resin layer is subjected to a silane treatment in order to improve the adhesion between the resin and the copper foil, thereby improving the adhesion under normal conditions. However, when such a silane treatment is performed, there is a tendency that the uniform treatment of the silane is 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 composed of fine roughened particles is provided on one side of the copper foil. As an example of forming fine coarse particles, for example, electrolysis is performed in a plating bath to which a chelating agent such as trisodium citrate is added. When the copper foil of this embodiment is used for a high-frequency substrate, although the adhesiveness and the like are excellent, the transmission loss is reduced due to the influence of the fine unevenness on the surface, and further the required characteristics are insufficient.

Patent Document 7 discloses a copper foil obtained by applying a finely roughened particle-treated layer of copper to at least one side of the copper foil. In the examples, coarse particles were made finer by adding disodium triethylenetriamine pentaacetate as a chelating agent to the rough plating bath. However, when the copper foil of this embodiment is used for a high-frequency substrate, the transmission loss is reduced due to the influence of the fine unevenness on the surface, and further, the required characteristics are insufficient.

[Prior Art Literature] (Patent Literature) Patent Literature 1: Japanese Patent Laid-Open No. 2013-158935 Patent Literature 2: Japanese Patent Laid-Open No. 4833556 Patent Literature 3: Japanese Patent Laid-Open No. 2013-147688 Patent Literature 4: International Patent Publication No. 2011/090175 Patent Literature 5: International Publication No. 2006/134868 Patent Literature 6: Japanese Patent Laid-Open No. 2006-278881 Patent Literature 7: Japanese Patent Laid-Open No. 2007-332418

[Problems to be Solved by the Invention] The present invention addresses the high performance and high performance of information communication equipment that has been made high-frequency for high-speed transmission and processing of large-capacity information. The object of the present invention is to provide a surface-treated copper foil and the use of Copper-clad laminated board, the surface-treated copper foil can ensure sufficient adhesion to the insulating substrate, and has high reflow heat resistance and transmission characteristics. The relative dielectric constant and dielectric loss tangent of the insulating substrate are low, so that the dielectric Excellent characteristics.

[Technical means to solve the problem] The present inventors made repeated efforts, and found that the cross-section length Da measured along the uneven surface of the surface roughening layer in a cross section orthogonal to the surface of the copper foil substrate is larger than that along the copper foil substrate. The ratio Da / Db (hereinafter also referred to as the "line length ratio") of the length Db measured decently has a great influence on the reflow heat resistance. In addition, the present inventors have also found that in the surface roughening treatment of forming a surface roughening layer having a concave-convex surface on a copper foil substrate by electrodeposition of roughened particles, the average height difference of the unevenness on the uneven surface is controlled. The amount of silane adhesion between H and the silane coupling agent layer formed on the surface roughening layer directly or at an intermediate layer can obtain a copper foil that exhibits excellent properties in terms of reflow heat resistance, adhesion and transmission characteristics. To complete the present invention.

That is, the gist of the present invention is structured as follows. (1) A surface-treated copper foil obtained by providing a surface roughened layer on a copper foil substrate, characterized in that the surface roughened layer is formed by roughening particles to form an uneven surface. In the cross section of the copper foil base surface orthogonal, the ratio (Da / Db) of the creeping length (Da) measured along the uneven surface of the surface roughening layer to the creeping length (Db) measured along the copper foil base surface is at In the range of 1.05 to 4.00, the average height difference (H) of the unevenness in the uneven surface is in the range of 0.2 to 1.3 µm. Furthermore, the roughened surface has a thickness of 0.0003 to 0.0300 mg / Silane coupling agent layer formed by dm ² silane adhesion amount.

(2) The surface-treated copper foil as described above, wherein the uneven surface has a necked shape. (3) The surface-treated copper foil as described above, wherein the ratio of the creeping length (Da / Db) is in a range of 1.05 to 3.20, and the average height difference (H) of the unevenness is in a range of 0.2 to 0.8 µm. When the foil and the insulating substrate are laminated, the number of bubbles on the interface between the surface roughened layer and the insulating substrate is 2.5 lines on the copper foil substrate, which is perpendicular to the manufacturing direction of the copper foil, that is, the width direction of 2.54 µm. the following. The production direction of the copper foil refers to the length direction of the roll in the case of electrolytic copper foil, and refers to the rolling direction (rolling direction) in the case of rolling the copper foil.

(4) The surface-treated copper foil as described above, wherein the ratio of the length along the surface (Da / Db) is in a range of 1.05 to 1.60, and the average height difference (H) of the unevenness is in a range of 0.2 to 0.3 µm, and On the line of 2.54 µm in the width direction of the foil substrate, the number of bubbles at the interface between the surface roughened layer and the insulating substrate is 1 or less. (5) The surface-treated copper foil as described above, 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 as described above, wherein the intermediate layer is composed of at least one layer selected from a base layer containing Ni, a heat-resistant treatment layer containing Zn, and a rust-resistant treatment layer containing Cr. (7) The surface-treated copper foil as described above, wherein the silane coupling agent layer is selected from the group consisting of epoxy-based silane, amine-based silane, vinyl-based silane, methacrylic-based silane, acrylic-based silane, and styrene-based At least one kind of silane, sulfonylurea-based silane, mercapto-based silane, sulfide-based silane, and isocyanate-based silane. (8) A copper-clad laminated board manufactured by using the above-mentioned surface-treated copper foil, and having an insulating substrate on a surface of the surface-roughened layer side of the surface-treated copper foil.

(9) A copper-clad laminated board having an insulating substrate on the surface roughened layer side of a surface-treated copper foil, the surface-treated copper foil is formed by providing the aforementioned surface roughened layer on a copper foil substrate, and the copper-clad The laminated board is characterized in that the interface length (Da ') measured along the interface between the surface roughened layer and the insulating substrate in a cross section orthogonal to the copper foil base surface is measured relative to the copper foil base surface. The ratio (Da '/ Db) of the creeping length (Db) is in the range of 1.05 to 4.00, and the average height difference (H') of the unevenness in the aforementioned interface is in the range of 0.2 to 1.3 µm. Further, the aforementioned roughened layer and A silane coupling agent layer having a silane adhesion amount of 0.0003 to 0.0300 mg / dm ² directly or spaced between the insulating substrates. (10) The copper-clad laminated board as described above, wherein the number of bubbles at the interface between the surface 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 substrate.

(Effects of the Invention) According to the present invention, it is possible to provide a surface-treated copper foil which can ensure sufficient adhesion to an insulating substrate and has high reflow heat resistance and transmission characteristics. The insulating substrate has a relative dielectric constant and a dielectric constant. The loss tangent is low and the dielectric characteristics are excellent, so that it can cope with the high-performance and high-performance information communication equipment of high-frequency transmission and processing of large-capacity information at high speed. The present invention can also provide a copper-clad laminated board made of the surface-treated copper foil.

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

The copper foil 110 may be appropriately selected from an electrolytic copper foil, an electrolytic copper alloy foil, a rolled copper foil, or a rolled copper alloy foil depending on the application and the like. The surface roughening layer 120 is provided by subjecting the copper foil substrate 110 to a surface roughening treatment, and the surface is formed with fine grains and fine irregularities. In this surface roughening treatment, a granular electrodeposition is formed by forming a so-called scorched coating by performing electrodeposition of copper while generating hydrogen at a current density exceeding a limit current density while generating hydrogen. Fine uneven surface. In the present invention, such a fine uneven surface is simply referred to as an uneven surface. The roughened particles in the present invention refer to the granular electrodeposited material.

Further, in the present invention, in a cross section orthogonal to the copper foil base surface, the creepage length Da measured along the uneven surface of the surface roughening layer 120 is equal to (a) the creepage length Db measured along the copper foil base surface ( Line length) ratio Da / Db is in the range of 1.05 to 4.00. The line length ratio Da / Db may be in a range of 1.05 to 3.20, and the line length ratio Da / Db may also be in a range of 1.05 to 1.60.

If the wire length ratio Da / Db is less than 1.05, the reflow resistance will be lowered and satisfactory performance will not be obtained. If the line length ratio Da / Db exceeds 4.00, the unevenness on the surface will increase excessively, so the transmission loss will be increased due to the skin effect, which will cause the transmission characteristics to deteriorate. Therefore, the line length ratio Da / Db is between 1.05 and 4.00. range. The method for measuring the line length ratio Da / Db will be described below.

The present inventors worked hard to investigate the reason why the wire length ratio Da / Db affects the heat resistance of reflow soldering. As a result, they obtained the following new insights. First, a method for preparing a test piece for a reflow heat resistance test will be described. An insulating substrate (base material) formed by laminating copper foils 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 and remove all the copper foil. Next, on both sides of the insulating substrate (base material) remaining after the core layer is etched, a prepreg layer made of an insulating material and a copper foil are laminated to produce a reflow test piece. The cross-section of the reflow test piece was observed, and as a result, 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 confirm that in the reflow heat resistance test, because the sample (test piece) is exposed to a high temperature of about 260 ° C, the low molecular weight components in the insulating substrate (base material) will volatilize, and the volatile gas volume will be stored in the insulating substrate and the Areas with weak adhesion between the dip layers are the cause of interlayer peeling. Therefore, it is generally considered that if the line length ratio Da / Db is less than 1.05, the area copied by etching will decrease, and as a result, the area where the insulating substrate (base material) contacts the prepreg layer will decrease, resulting in A region with low adhesion between the two layers, so that the gas volatilized from the substrate during heating will accumulate in this region between the layers, causing peeling to occur easily.

In the present invention, after diligent research, it was found that by controlling the line length ratio Da / Db and the average height difference H of the unevenness to an appropriate range, a roughened shape having a necked shape can be obtained, which can be used in common examples. Compared with copper foil whose surface area is controlled, the heat resistance is significantly improved. That is, if Da / Db is increased within a range of the average height difference H of the unevenness of the present case so as not to reduce the transmission characteristics, the contour length of the roughened layer becomes longer, and as a result, a large amount of necked shape can be obtained. Roughen the shape. By increasing the necked shape, although the roughening is fine, the strong anchoring effect is exhibited, and the adhesion between the copper foil and the insulating substrate (resin substrate) is enhanced and the heat resistance is improved. Therefore, within the scope of the patent application of this case, by controlling Da / Db and the average height difference H while maintaining high transmission characteristics, the heat resistance is significantly improved compared with known examples.

As a parameter for quantifying the roughened shape, as shown in Patent Document 4 (WO2011-090175), a surface area ratio measured by a laser microscope is known. However, as a problem, for example, as shown in FIG. 1, when (a) roughening with a necked shape 11 and (b) roughening without a necked shape exist, theoretically, the surface area is measured by a laser microscope At this time, since the laser light was projected from the copper foil in the vertical direction to measure the height, it was difficult to measure the difference in the presence or absence of a necked shape in FIGS. 1 (a) and 1 (b). That is, although the shape of the surface directly irradiated with the laser light can be measured, if the necked portion is projected from the vertical direction, the laser light becomes a shadow, so that it is impossible to measure the shape of the portion that is not directly irradiated with the laser light.

Therefore, as shown in the embodiment of Patent Document 4, when the surface area ratio is measured using a laser microscope, the presence or absence of the necking shape cannot be reflected in the measured value. Therefore, the copper is controlled by the surface area ratio measured by the laser microscope. The surface shape of the foil is not suitable for this case. In addition, the aspect ratio shown in Patent Document 4 only indicates the ratio of the "height" to the "width" of the roughened particles, and the necking shape is not considered at all.

Furthermore, if the insulating substrate is closely adhered to the surface roughened layer side of the copper foil having the surface roughened layer obtained in the above embodiment to form a copper-clad laminated board, there is an interface along the surface roughened layer and the insulated substrate. The measured interface length (Da ') tends to be slightly reduced due to the pressure contact with the insulating substrate. Therefore, it is necessary to maintain the above-mentioned wire length ratio within the above-mentioned range after the insulating substrates are tightly adhered, and on a cross section orthogonal to the copper foil base surface after the insulating substrates are tightly adhered, the roughening layer along the surface and the aforementioned The ratio (Da '/ Db) of the interface length (Da') measured at the interface of the insulating substrate to the creepage length (Db) measured along the aforementioned copper foil substrate surface is in the range of 1.05 to 4.00, and can be obtained from the above (Da / Db).

Therefore, in the present invention, the average height difference (corresponding to the average height of the roughened particles) H of the unevenness on the uneven surface of the copper foil is set in the range of 0.2 to 1.3 µm. If the average height difference H of the unevenness on the uneven surface is less than 0.2 µm, the anchoring effect is weak, and sufficient adhesion between the copper foil and the insulating substrate cannot be obtained. If the average height difference H of the unevenness on the uneven surface exceeds 1.3 µm, the unevenness on the surface becomes too large, and the transmission loss becomes large due to the skin effect. In addition, the average height difference H of the unevenness on the uneven surface may be in a range of 0.2 to 0.8 μm, and the average height difference H of the unevenness on the uneven surface may be in a range of 0.2 to 0.3 μm.

Furthermore, if the insulating substrate is closely adhered to the surface roughened layer side of the copper foil having the surface roughened layer obtained in the above embodiment to form a copper-clad laminated board, the unevenness H of the surface roughened layer may be The insulating substrate tends to be slightly reduced in pressure contact. Therefore, it is necessary to maintain the average height of the unevenness within the above-mentioned range after the insulating substrate is closely adhered, and to make the average height difference of the unevenness on the uneven surface by the cross section orthogonal to the copper foil base surface after the insulating substrate is tightly adhered ( This corresponds to the average height of the coarsened particles) H 'is in the range of 0.2 to 1.3 µm, and the same effect as in the case of H described above can be obtained.

The present inventors investigated a method of controlling Da / Db in a range of an appropriate uneven average height difference (H), and found that in the roughening methods of Documents 6 and 7, because the concentration of the chelating agent is high, the The formation of a large number of fine roughened particles on the surface of copper foil will increase the Da / Db excessively, and as a result, the transmission loss will increase. The present inventors worked hard to study the countermeasures to this problem, and as a result, they learned that by making the concentration of the chelating agent lower than the previous concentration, the particles will become an appropriate size, and the Da / Db can be controlled in the most suitable range. High adhesion and heat resistance while reducing transmission loss. Specifically, the concentration of the chelating agent added to the plating bath may be in a range of 0.1 to 5 g / L.

As a mechanism of the reaction, it is presumed that the low-concentration chelating agent reduces the overvoltage during electrolysis compared to the high-concentration condition, thereby reducing the nucleation frequency. Therefore, it is possible to appropriately suppress the effect of miniaturization and form an appropriate size. Roughened particles. In addition, it is generally considered that when the chelating agent has a low concentration, since the number of chelate molecules in the plating bath is small, most of the chelates are coordinated metal ions (such as Cu) and the chelate. The state of uncoordinated metal ions mixed together in the plating bath. Due to the difference in the coordination state of the chelate, particles with different precipitation modes are formed at the same time, thereby becoming a complex particle shape with a necked shape, which is suitable for the appropriate The range of Da / Db can also have a high degree of heat resistance and adhesion. When the chelating agent is used at a low concentration, growth in the height direction of the roughened particles is appropriately suppressed, so that the average height difference H of the unevenness is in a proper range. According to the precipitation mode in the state where most of the chelate complexed metal ions (such as Cu) and chelate uncoordinated metal ions are mixed together in the plating bath, the precipitated orientation is random (random Properties), so growth in the height direction is suppressed.

In addition, the inventors have found that, as a method of appropriately controlling Da / Db, a method of adding two kinds of chelating agents to the surface roughening treatment bath is also effective. It is speculated that by adding two kinds of chelating agents, metals with different coordination states of the chelate are electrolyzed at the same time, and particles of different shapes are simultaneously precipitated, thereby coarsening the shape of the particles to become complicated, thereby easily showing an anchoring effect. As another method for proper management of Da / Db, it is also effective to form a roughened particle using a current density of 70 to 90 A / dm ² which was previously unused due to unfavorable conditions such as powder dropping. However, if the processing time is long, the particles will grow excessively in the vertical direction and it becomes easy to drop the powder. Therefore, it is necessary to shorten the processing time. If the current density is high, the amount of hydrogen generated on the cathode increases. It is presumed that before the hydrogen gas detached from the cathode and entered the liquid, it was a spot that could not be plated. Therefore, the roughened precipitation point becomes discontinuous, and as a result, a surface shape with an appropriate number of irregularities can be obtained.

In the present invention, a silane coupling agent layer is formed on the surface roughened layer 120 directly or at an intermediate layer with a silane adhesion amount of 0.0003 to 0.0300 mg / dm ² . If the silane coupling amount of the silane coupling agent constituting the silane coupling agent layer is less than 0.0003 mg / dm ² , the reflow heat resistance will decrease. In addition, if the adhesion amount exceeds 0.0300 mg / dm ² , the silane coupling agent layer becomes too thick, and the adhesion strength is reduced. Furthermore, the silane coupling amount of the silane coupling agent constituting the silane coupling agent layer may be 0.0005 to 0.0120 mg / dm ² .

Further, as a method for forming the silane coupling agent layer, for example, the following method may be mentioned: a silane coupling agent solution is directly applied on the uneven surface of the surface roughening layer 120 or indirectly through an intermediate layer, and then air-dried or heated to dry. form. Regarding the drying of the coated coupling agent layer, the effect of the present invention can be fully exerted as long as the water evaporates, but from the viewpoint of promoting the reaction between the silane coupling agent and the copper foil, it is preferably performed at a temperature of 50 to 180 ° C. Heat and dry.

It is preferred that the silane coupling agent layer contains epoxy-based silane, amine-based silane, vinyl-based silane, methacrylic-based silane, acrylic-based silane, styryl-based silane, ureton-based silane, mercapto-based silane, and sulfide Any one or more of the silanes and isocyanate-based silanes. It is preferable that the uneven surface of the present invention has a large number of necked shapes. Although having a large number of necked shapes causes coarsening and fineness, it can exhibit a strong anchoring effect and enhance the adhesion and heat resistance of the copper foil to the insulating substrate. To form a concave-convex surface having a large number of necked shapes, as described above, roughening can be performed by keeping the average height difference H of the unevenness in a range of 0.2 to 1.3 µm and controlling Da / Db in a range of 1.4 to 4.0. The contour length of the layer becomes longer, and as a result, a roughened shape having a large number of necked shapes is obtained.

In the present invention, when the copper foil and the insulating substrate are laminated, the number of bubbles at the interface between the surface roughening layer and the insulating substrate is preferably 2 or less in the width of the substrate (for example, 2.54 µm). In this case, in investigating the factors affecting the heat resistance of reflow soldering, it was found that in addition to the above-mentioned wire length ratio Da / Db and the average height difference H, the interface between the roughened surface of the copper foil and the insulating substrate in the reflow solder test strip The number of bubbles also has a large effect. Here, the term "bubble" in the present case refers to a region where the insulating substrate is not filled at the interface between the surface roughened layer and the insulating substrate, and the size thereof is 1.0 µm or less in terms of major diameter. If the number of bubbles at the interface between the surface roughened layer of the copper foil and the insulating substrate is large, during heating in the reflow test, the gas volatilized from the insulating substrate will be concentrated in the bubble portion and the gas pressure in the bubble will increase. , Causing interlayer peeling to easily occur.

Therefore, the present inventors have worked hard to investigate a method for reducing the number of bubbles at the interface between the surface roughened layer and the substrate, and as a result, it has been found that appropriately controlling the processing conditions of the silane coupling agent is an effective method. Specifically, it is a method of first adding alcohol to an aqueous solution of a silane coupling agent. Examples of the alcohol include methanol, ethanol, isopropanol, and n-propanol. By adding alcohol, the dispersibility of the silane molecules in the solution is improved, and the silane coupling agent can be treated uniformly on the surface roughened layer of the copper foil, so the wettability to the resin is improved. Furthermore, it is estimated that when the substrate and the copper foil are laminated at a high temperature, the molten resin sufficiently wets the surface roughened layer to improve the filling property, thereby reducing the number of bubbles at the interface between the surface roughened layer and the substrate. Further, it is also effective to extend the time from the treatment of the copper foil with the silane aqueous solution to the drying with warm air. It is presumed that by extending the time from the treatment with an aqueous silane solution to the drying with warm air, the silane molecules can be regularly aligned on the surface of the surface roughened layer of the copper foil to improve the wettability of the resin. The number of bubbles at the interface between the surface 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 surface roughened layer by the resin is not taken into account, and the number of bubbles at the interface between the surface roughened layer and the insulating substrate is likely to increase.

The number of bubbles at the interface between the surface roughened layer of the copper foil and the insulating substrate may be less than two on the 2.54 µm line in the width direction of the substrate. The number of bubbles may also be 1 or less on the line. If the number of bubbles at the interface between the surface 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 will be concentrated in the bubble portion, and interlayer peeling will easily occur. , And the reflow resistance (between the copper foil and the prepreg layer) tends to decrease.

As another embodiment, between the surface roughening layer 120 and the silane coupling agent layer, at least one layer selected from a base layer containing Ni, a heat-resistant treatment layer containing Zn, and a rust-resistant treatment layer containing Cr may be further provided. middle layer. If, for example, copper (Cu) in the copper foil substrate 110 or the surface roughened layer 120 diffuses to the insulating substrate side to cause copper damage and reduce the adhesion, it is preferable to use the surface roughened layer 120 and the silane coupling agent. A base layer 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) -rhenium (Zn). Among these, nickel-phosphorus is preferable from the viewpoint of suppressing nickel residue during copper foil etching during circuit wiring formation.

When it is necessary to further improve heat resistance, it is preferable to form a heat-resistant treatment layer containing zinc (Zn). The heat-resistant treatment layer is preferably made of, for example, zinc or an alloy containing zinc, that is, selected from zinc (Zn) -tin (Sn), zinc (Zn) -nickel (Ni), zinc (Zn) -cobalt (Co), zinc A zinc-containing alloy of at least one of (Zn) -copper (Cu), zinc (Zn) -chromium (Cr), and zinc (Zn) -vanadium (V). Among these, zinc-vanadium is particularly preferred from the viewpoint of suppressing undercuts during etching during circuit wiring formation. In addition, the "heat resistance" mentioned here refers to a property in which an insulating substrate is laminated on a surface-treated copper foil and heated to harden the resin, so that the adhesion strength between the surface-treated copper foil and the insulating substrate is not easily reduced. Features different from reflow heat resistance.

When it is necessary to further improve the corrosion resistance, a rust-resistant treatment layer containing Cr may be formed. Examples of the rust-preventive treatment layer include a chromium layer formed by chromium plating and a chromate layer formed by chromate treatment. When the above three layers, that is, the base layer, the heat-resistant treatment layer, and the rust-proof treatment layer are all formed, they can be formed on the surface roughened layer in this order, or only any one of the three layers can be formed according to the characteristics of use or purpose One 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 laminated board has an insulating substrate on the surface on the surface roughened layer side of the surface-treated copper foil. Insulating substrates for copper-clad laminates can be selected from thermosetting polyphenylene ether resins, thermosetting polyphenylene ether resins containing polystyrene polymers, polymers containing triallyl cyanurate, or copolymers Resin composition, epoxy resin composition modified by methacrylic acid or acrylic acid, phenol addition butadiene polymer, diallyl phthalate resin, divinylbenzene resin, polyfunctional methyl group Insulating resins such as acrylic fluorene-based resins, unsaturated polyester resins, polybutadiene resins, styrene-butadiene, crosslinked polymers of styrene-butadiene and styrene-butadiene, and the like. In the case of manufacturing a copper-clad laminated board, it may be manufactured by heat-pressing a surface-treated copper foil having a silane coupling agent layer and an insulating substrate and bringing them into close contact. Furthermore, a copper-clad laminated board produced by coating a silane coupling agent on an insulating substrate and closely bonding the insulating substrate to a copper foil having a rust-preventive treatment layer on the outermost surface by heating and pressing also has the same effect as the present invention.

[Production of Surface-treated Copper Foil] (1) Step of Forming Surface Roughened Layer A surface roughened layer having an uneven surface is formed on a copper foil by electrodeposition 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) make roughened particles having different shapes easily precipitate simultaneously. From the viewpoint of (i), for example, a method of reducing the overvoltage during electrolysis to reduce the nucleation frequency can be adopted. As a specific example, a method of making the chelating agent at a low concentration can be mentioned. Alternatively, a method of shortening the processing time by increasing the current density during roughening processing to 70 to 90 A / dm ² may be adopted.

Here, it is appropriate that the concentration of the chelating agent added to the plating bath for surface roughening treatment is 0.1 to 5 g / L. Examples of the chelating agent include chelating agents such as DL-malic acid, sodium EDTA solution, sodium gluconate, and pentasodium diethylenetriamine pentaacetate (DTPA). From the viewpoint of (ii), for example, a method in which metals with different coordination states of chelates are simultaneously electrolyzed may be adopted. As a specific example, a method of adding two kinds of chelating agents to a surface roughening treatment bath may be mentioned. method. As an example, there is a combination of DL-malic acid and DTPA.

In addition, in order to make the number of bubbles in the interface between the surface roughened layer and the insulating substrate be 2 or less on the 2.54 µm line in the width direction of the copper foil substrate, methods such as improving the wettability of the surface roughened layer to the surface of the insulating substrate can be adopted. . Therefore, for example, (i) the silane coupling treatment is performed so that the silane coupling agent layer is uniformly formed on the surface roughened layer, and (ii) the silane coupling agent layer is regularly aligned in the silane coupling agent layer. Silane coupling processing and other methods. Specific examples of (i) include a method of adding an alcohol to an aqueous solution of a silane coupling agent, and specific examples of (ii) include a method in which the copper foil is processed after the roughening treatment of the copper foil with the silane solution and before drying with warm air. How to extend time.

(2) Forming step of base layer A base layer containing Ni is formed on the surface roughening layer as necessary. (3) Step of forming a heat-resistant treatment layer A heat-resistant treatment layer containing Zn is formed on the surface roughened layer or the base layer as necessary. (4) the step of forming the rust-preventive treatment layer, immersing the copper foil on which the above-mentioned layer has been formed in an aqueous solution containing a Cr compound having a pH value lower than 3.5, and performing chrome plating treatment at a current density of 0.3 A / dm ² or more, Thereby, an anti-rust treatment layer is formed on the surface roughening layer, the base layer, or the heat-resistant treatment layer. (5) The step of forming the silane coupling agent layer forms a silane coupling agent layer on the surface roughening layer, the base layer, the heat-resistant treatment layer or the rust-proof treatment layer.

[Production of copper-clad laminated board] The copper-clad laminated board of the present embodiment is manufactured by the following steps. (1) Production of surface-treated copper foil The surface-treated copper foil was produced in accordance with the above (1) to (5). (2) The manufacturing (lamination) step of the copper-clad laminated board overlaps the surface-treated copper foil produced in the above manner with the insulating substrate so that the surface of the silane coupling agent layer constituting the surface-treated copper foil and the bonding surface of the insulating substrate On the other hand, a copper-clad laminated board is manufactured by performing heating and pressurizing treatment to make the two adhere to each other. In addition, it should be noted that the above contents only show examples of embodiments of the present invention, and various changes can be made without departing from the spirit of the present invention. [Example]

(Example 1) Under the following conditions, a surface-treated copper foil was produced as a copper foil base body having a thickness of 18 µm without roughening (surface roughness Rz is about 0.8 µm). (1) Formation of surface roughening layer For the surface roughening treatment of the surface of the copper foil substrate, the surface roughening layer is formed in the following order: the surface roughening plating treatment 1 is performed under the conditions of Table 1, and then the following Shown surface roughening plating treatment 2.

[Table 1]

(Surface roughening plating treatment 2) Copper sulfate: 13 to 72 g / L based on copper concentration Sulfuric acid concentration: 26 to 133 g / L Liquid temperature: 18 to 67 ° C Current density: 3 to 67 A / dm ² Processing time : 1 second to 1 minute and 55 seconds

(2) The Ni-containing base layer is formed on the surface of the copper foil substrate and a surface roughened layer is formed. Then, on the surface roughened layer, electroplating is performed under the following nickel plating conditions, thereby forming the base layer (Ni adhesion amount) 0.06 mg / dm ² ). <Nickel plating conditions> Nickel sulfate: 5.0 g / L ammonium persulfate based on nickel metal 40.0 g / L boric acid 28.5 g / L current density 1.5 A / dm ² pH value 3.8 temperature 28.5 ℃ time 1 second to 2 minutes

(3) Formation of heat-resistant treatment layer containing Zn After forming a base layer, a heat-resistant treatment layer was formed by plating on the base layer under the following zinc plating conditions (the amount of Zn attached: 0.05 mg / dm ² ) . <Zinc plating conditions> Zinc sulfate heptahydrate 1 to 30 g / L Sodium hydroxide 10 to 300 g / L Current density 0.1 to 10 A / dm ² Temperature 5 to 60 ° C Time 1 second to 2 minutes

(4) Formation of rust-resistant treatment layer containing Cr After forming a heat-resistant treatment layer, the heat-resistant treatment layer was treated under the following chrome plating treatment conditions to form a rust-resistant treatment layer (Cr adhesion amount: 0.02 mg / dm ² ). <Chrome plating conditions> (Chrome plating bath) Chromic anhydride CrO ₃ 2.5 g / L pH value 2.5 Current density 0.5 A / dm ² Temperature 15 to 45 ° C Time 1 second to 2 minutes

(5) Formation of Silane Coupling Agent Layer After the rust-preventive treatment layer is formed, methanol or ethanol is added to the silane-coupling agent aqueous solution under the conditions shown in Table 2 and the coating is adjusted to a predetermined pH. Value of process fluid. Thereafter, the silane coupling agent layer having a silane adhesion amount shown in Table 3 was formed by maintaining the silane coupling agent in the amount shown in Table 3 by keeping it for a predetermined time. The values in italics in Table 3 represent values outside the appropriate range of the present invention.

[Table 2]

[table 3]

(Examples 2 to 18) The surface roughening plating treatment 1 was performed in accordance with the content of Table 1, and the silane coupling agent treatment was performed in accordance with the content of Table 2. The treatment was performed in the same manner as in Example 1. (Comparative Example 1 to Comparative Example 7 and Comparative Example 9 to Comparative Example 14) The surface roughening plating treatment 1 was performed according to the content of Table 1, and the silane coupling agent treatment was performed according to the content of Table 2. In Example 1, the treatment was performed in the same manner.

(Comparative Example 8) A roll-shaped liquid crystal polymer film (Vecster (registered trademark) CT-Z manufactured by Kuraray Co., Ltd.) was used and immersed in a potassium hydroxide solution (liquid temperature 80 ° C) for a processing time of 10 minutes. Etching and surface roughening are performed. Next, an electroless copper plating layer was formed on the surface-processed thermoplastic resin film by the electroless copper plating bath described below.

＜ Electroless copper bath ＞ Copper sulfate‧pentahydrate (based on copper content) 19 g / L HEEDTA (chelating agent) 50 g / L Sodium phosphinate (reducing agent) 30 g / L Sodium chloride 20 g / L Disodium hydrogen phosphate 15 g / L Thereafter, an electroplated copper layer was formed so that the entire thickness of the copper plating layer was 20 µm. The copper plating layer included an electroless copper layer formed on a thermoplastic resin film using a copper sulfate bath. In addition, Comparative Example 8 was produced under conditions satisfying the scope of the invention described in Patent Document 1.

(Characteristic Evaluation of Test Strips) Various measurements and evaluations were performed on each test strip. The results are shown in Table 3. (1) The line length ratio Da / Db and the average height difference H of the unevenness on the uneven surface are measured on a cross section orthogonal to the copper foil base surface (plane direction P) shown by the double arrow in FIG. The ratio Da / Db of the creeping length Da measured on the uneven surface 120 of the surface roughened layer to the creeping length Db measured along the surface of the copper foil base 110 is defined as the line length ratio. If the uneven surface of the surface roughening layer in this cross section has a shape having more or more irregularities, the line length ratio becomes larger.

Each test piece was processed with an ion polishing apparatus (manufactured by Hitachi, Ltd .: IM4000 (model)), and a cross section of each processed test piece was observed using a scanning electron microscope (SEM: Hitachi, Ltd .: SU8020 (model)). Then, the above-mentioned wire length ratio Da / Db was measured according to the procedure shown below. Calculated based on the observation image magnified at 10,000 times (the actual width of the field of view in the image in this case is 12.7 µm). The image analysis software Winroof (Mitani Corporation) was used to analyze the observation image of the SEM, thereby measuring the creeping length Da on the uneven surface of the surface roughened layer as shown by the thick line in FIG. 3. Measurements can also be performed in the same manner using other image analysis software. Regarding the magnification of the SEM, the width of the SEM image is preferably in a 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 was used as Da / Db.

Next, the average height difference of the uneven surface was measured as follows. First, magnify the observation magnification to 200 times (the actual width of the field of view in the image in this case is 63.5 µm), and make the extension direction of the uneven surface consistent with the horizontal direction of the screen within an error range of ± 1 ° at any position. Next, magnify the observation magnification to 10,000 times (the actual width of the field of view in the image in this case is 12.7 µm), and set the bottom position of the first recessed portion to point A. The bottom position of the first recessed portion is an arbitrary position in the SEM image. Position of the lowest point in the unevenness shown in the inner surface forming the uneven surface. Then, among the remaining recesses other than the first recess and the recess adjacent to the first recess, the bottom position of the second recess with the bottom position being the lowest point position is set to point B. Then, a straight line connecting the A point and the B point is set as the baseline BL1 (FIG. 4 (a)). Thereafter, in the SEM image magnified to 50,000 times (the actual width of the field of view in the image of this case is 2.54 µm), a baseline BL2 parallel to the baseline BL1 is drawn, and passes through the bottom position of the third recess, the third The bottom position of the concave portion is the lowest point of the unevenness that forms the uneven surface at any position. The distance from the baseline BL2 to the vertex of the convex portion that is furthest in the vertical direction is set as the height difference H and measured (Figure 4 ( b)). In this embodiment, the height difference is measured at five visual fields and the average value is used as the average height difference H.

(2) The number of bubbles at the interface between the surface roughened layer and the insulating substrate is shown in FIG. 5. The number of bubbles at the interface between the surface roughened layer 43 and the insulating substrate 42 is measured in the following order. First, a laminated machine was used to laminate the insulating substrate 42 (prepreg layer) and the copper foil 43 under standard lamination conditions recommended by the insulating substrate manufacturer to produce a laminated body (in this case, MEGTRON 6 of Panasonic Corporation was used). : R-5670 is used as the insulating substrate 42 and laminated under the following pressing conditions: a pressing temperature of 200 ° C., a pressing pressure of 35 kgf / cm ² , and a pressing time of 160 minutes). Next, the laminated body was processed using the ion milling device, and the cross-section of the processed laminated body was magnified to 50000 times using the scanning electron microscope (the actual width of the field of view in the image in this case is 2.54 µm), and observed The interface between the surface roughened layer 43 of the laminated body and the insulating substrate 42. As shown in FIG. 5, the number of bubbles 41 existing at the interface between the surface roughened layer 43 and the insulating substrate 42 was measured at 10 places with a width of 2.54 μm, and the average of the number of bubbles at 10 places was used as the surface. The number of bubbles Vi at the interface between the roughened layer 43 and the insulating substrate 42. The term "bubbles" in this case refers to the area where the insulating substrate is not filled in the interface between the surface roughened layer and the insulating substrate, and the size is 1.0 µm or less in terms of major diameter.

(3) Measurement of Silane Adhesion A fluorescent X-ray analyzer (ZSXPrimus, manufactured by RIGAKU, Inc., analysis diameter: 35 mm) was used for analysis. (4) Measurement of the line length ratio Da '/ Db and the average height difference H' of the unevenness on the uneven surface after the insulating substrate is in close contact. After bonding each copper foil to the insulating substrate, the line length ratio Da '/ Db and the uneven surface The average height difference H 'of the unevenness in the middle was performed in the same manner as in the above-mentioned measurement of Da / Db and H.

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

(6) Adhesion 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 hardening conditions of the insulating (resin) substrate were 210 ° C and 1 hour. A universal material testing machine (TENSILON, manufactured by A & D) was used to adhere the copper foil to the insulating substrate, and then the test piece was etched into a 10 mm wide circuit wiring, and the insulating side was fixed to the stainless steel plate with double-sided tape. Then, the circuit wiring was peeled at a speed of 50 mm / min in the direction of 90 degrees to obtain the adhesion strength. Regarding the initial adhesiveness, a case where the peel strength was 0.4 kN / m or more was regarded as acceptable, and a case where the peel strength was less than 0.4 kN / m was regarded as unacceptable.

(7) Reflow heat resistance (between the copper foil and the prepreg layer) First, a method for preparing a test piece for the reflow heat resistance test (between the copper foil and the prepreg layer) will be described. 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 × 100 mm. Next, the prepared test piece was put into a reflow furnace, and was subjected to heating 10 times at a top temperature of 260 ° C. and a time of 10 seconds. After heating under the above conditions, the expander observes the cross section of the expanded area with a microscope to confirm whether there is interlayer peeling between the copper foil and the prepreg layer. A person with no interlayer peeling between the copper foil and the prepreg layer was judged as "○ (pass)", and a person with interlayer peeling between the copper foil and the prepreg layer was judged as "Δ (pass)", Those who experienced interlayer peeling at two or more places between the copper foil and the prepreg layer were judged to be "× (Failed)". 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, a method for producing a test piece for the reflow heat resistance test (between the core layer and the prepreg layer) will be described. A double-layered insulating substrate with a copper foil is 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. The double-area layer due to the etched core layer was used as a prepreg layer and a copper foil of the insulating substrate to produce a reflow test piece. 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 put into a reflow furnace, and was subjected to heating 10 times at a top temperature of 260 ° C. and a time of 10 seconds. After heating under the above-mentioned conditions, those who did not have interlayer peeling between the core layer and the prepreg layer were judged to be "○ (pass)", and those who had interlayer peeling between the core layer and the prepreg layer were judged to be "Δ (pass)" judged "x (unacceptable)" if the interlayer peeling occurred at two or more places between the core layer and the prepreg layer. The content of the reflow test is based on JIS C 60068-2-58.

It is clear from Table 3 that Examples 1 to 18 are all acceptable grades in terms of all properties of adhesion to the insulating substrate, transmission characteristics, and reflow heat resistance. On the other hand, in Comparative Example 1, the line length is smaller than Da / Db and Da '/ Db, and the average height difference H and H' of the unevenness on the uneven surface is also low, so the adhesion strength is low and the reflow heat resistance is also poor. . With regard to Comparative Example 2, the line length is larger than Da / Db and Da '/ Db, and the average height difference H and H' of the unevenness in the uneven surface is also high, so the transmission loss is large and the transmission characteristics are poor. Regarding Comparative Example 3, since the wire length was smaller than Da / Db and Da / Db 'and the amount of silane attached was also small, the reflow resistance was poor. In Comparative Example 4, the line length was smaller than Da / Db and Da '/ Db, the average height difference H and H' of the unevenness on the uneven surface was low, and the silane adhesion amount was large, so the adhesion strength was low. Regarding Comparative Examples 5 to 7, since the line length is larger than Da / Db and Da / Db ', the average height difference H and H' are large, and the number of bubbles at the interface between the surface roughened layer and the insulating substrate is large, so reflow soldering is required. Poor heat resistance. In Comparative Example 8, the line length was smaller than Da / Db and Da '/ Db, 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 lengths are larger than Da / Db and Da '/ Db. Especially in Comparative Examples 9 to 11, the average height difference H and H' of the unevenness on the uneven surface is also high. Therefore, the transmission loss is large and the transmission characteristics are poor.

[Industrial Applicability] According to the present invention, it is possible to provide a surface-treated copper foil and a copper-clad laminated board made using the surface-treated copper foil. The surface-treated copper foil can ensure sufficient adhesion to the insulating substrate and simultaneously With high reflow heat resistance and transmission characteristics, this insulating substrate has excellent dielectric properties due to its low relative dielectric constant and dielectric loss tangent, so it can cope with high-performance high-frequency information communication equipment that can process large-capacity information at high speed. And high performance.

11‧‧‧ neck shape
110‧‧‧ copper foil substrate
120‧‧‧ surface roughening layer
Da‧‧‧Criminal length measured along the uneven surface of the surface roughening layer
Db‧‧‧Criminal length measured along the aforementioned copper foil substrate
P‧‧‧ substrate width
41‧‧‧ Bubble
42‧‧‧ Insulating substrate
43‧‧‧ surface roughening layer

FIG. 1 (a) is a cross-sectional view showing the state of the surface roughened layer having a necked shape according to the present invention; the so-called necked shape refers to the shape shown in FIG. The width of the root of the roughened particle is narrowed, so that the root of the roughened particle has a recess. FIG. 1 (b) is a cross-sectional view showing a state of a conventional surface roughening layer. FIG. 2 is a cross-sectional view schematically showing the average height difference H of the unevenness constituting the uneven surface, the uneven surface constituting the surface roughening layer. 3 is a cross-sectional view schematically showing a creeping length Da on the uneven surface of the surface roughening layer shown in FIG. 1. FIG. 4A is a cross-sectional view showing a baseline BL1 for measuring the average height difference H of the unevenness constituting the uneven surface, and the uneven surface constitutes a surface roughened layer. FIG. 4 (b) is a sectional view showing the baseline BL2 in the same manner. 5 is a cross-sectional view schematically showing air bubbles existing at an interface between a surface roughened layer and an insulating substrate.

Domestic hosting information (please note in order of hosting institution, date, and number) None

Information on foreign deposits (please note in order of deposit country, institution, date, and number) None

Da‧‧‧Criminal length measured along the uneven surface of the surface roughening layer

Db‧‧‧Criminal length measured along the aforementioned copper foil substrate

P‧‧‧ substrate width

Claims (10)

A surface-treated copper foil obtained by providing a surface roughened layer on a copper foil substrate, wherein the surface roughened layer has a plurality of roughened particles, and the surface of the surface roughened layer is configured as an uneven surface. The ratio of the creepage length (Da) measured along the uneven surface of the surface roughened layer to the creepage length (Db) measured along the copper foil base surface in a cross section orthogonal to the copper foil base surface (Da / Db) is in the range of 1.05 to 4.00, and the average height difference (H) of the unevenness in the uneven surface is in the range of 0.2 to 1.3 µm. Further, the surface roughened layer has an interval of 0.0003 to Silane coupling agent layer formed with a silane adhesion amount of 0.0300 mg / dm ² . The surface-treated copper foil according to claim 1, wherein the uneven surface has a necked shape. The surface-treated copper foil according to claim 1 or 2, wherein the ratio of the length along the surface (Da / Db) is in a range of 1.05 to 3.20 times, and the average height difference (H) of the unevenness is in a range of 0.2 to 0.8 µm. And when the copper foil and the insulating substrate are laminated, on a line on the copper foil substrate perpendicular to the manufacturing direction of the copper foil, that is, on a line of 2.54 µm in width, the interface between the surface roughening layer and the insulating substrate The number of bubbles is 2 or less. The surface-treated copper foil according to any one of claims 1 to 3, wherein the ratio of the length along the surface (Da / Db) is in a range of 1.05 to 1.60 times, and the average height difference (H) of the unevenness is in a range of 0.2 to In the range of 0.3 µm, when the copper foil and the insulating substrate are laminated, the number of bubbles at the interface between the surface roughened layer and the insulating substrate is 1 or less on a line of 2.54 µm in the width direction of the copper foil substrate. The surface-treated copper foil according to any one of claims 1 to 4, wherein the silane adhesion amount of the silane coupling agent layer is 0.0005 to 0.0120 mg / dm ² . The surface-treated copper foil according to any one of claims 1 to 5, wherein the intermediate layer is at least one selected from a base layer containing Ni, a heat-resistant treatment layer containing Zn, and a rust-resistant treatment layer containing Cr. 1 layer structure. The surface-treated copper foil according to any one of claims 1 to 6, wherein the silane coupling agent layer is selected from the group consisting of epoxy-based silane, amine-based silane, vinyl-based silane, methacrylic-based silane, At least one of an acrylic silane, a styryl-based silane, a sulfonylurea-based silane, a mercapto-based silane, a sulfide-based silane, and an isocyanate-based silane. A copper-clad laminated board having an insulating substrate on the surface of the surface-roughened layer side of the surface-treated copper foil according to any one of claims 1 to 7. A copper-clad laminated board is provided with an insulating substrate on a surface roughened layer side of a surface-treated copper foil. The surface-treated copper foil is formed by providing the foregoing surface roughened layer on a copper foil substrate. It is characterized in that the cross-section length (Da ') measured along the interface between the surface roughened layer and the insulating substrate in a cross section orthogonal to the copper foil base surface is relative to the creep length measured along the copper foil base surface ( The ratio of Db) (Da '/ Db) is in the range of 1.05 to 4.00 times, and the average height difference (H') of the unevenness in the interface is in the range of 0.2 to 1.3 µm. Furthermore, the surface roughening layer and the insulation are further reduced. A silane coupling agent layer having a silane adhesion amount of 0.0003 to 0.0300 mg / dm ² directly or spaced between the substrates. The copper-clad laminated board according to claim 9, wherein the number of bubbles at the interface between the surface roughened layer and the insulating substrate is 2.5 or less on a line of 2.54 µm in the width direction of the copper foil substrate.