TW202241702A - Copper foil with carrier, copper-clad laminate, and printed wiring board - Google Patents

Abstract

Provided is a copper foil with a carrier, with which excellent laser processability can be achieved. This copper foil with a carrier is provided with a carrier, a release layer, and an ultrathin copper foil in said order, wherein copper crystal grains that are present on the release-layer-side surface of the ultrathin copper foil have a plane size S1 of 50 nm to 600 nm as measured using an electron backscatter diffraction (EBSD) method.

Description

With carrier copper foil, copper foil laminate and printed wiring board

The invention relates to a copper foil with a carrier, a copper foil laminate and a printed wiring board.

In recent years, in order to increase the mounting density of printed wiring boards and make them smaller, multilayering of printed wiring boards has become more common. Such a multilayer printed wiring board is used in a large number of portable electronic devices to achieve weight reduction and miniaturization.

In the manufacture of this multilayer printed wiring board, the following method is widely used: For a laminate in which a substrate with an inner layer circuit and an outer layer copper foil are laminated through an insulating layer, a via hole is formed by laser processing, and by performing Filler plating is used to connect layers. Also, in laser processing in recent years, direct laser drilling processing in which guide holes are formed by directly irradiating laser light on ultra-thin copper foil (outer layer copper foil) is mostly used (for example, refer to Patent Document 1 (Japanese Patent Laying-Open No. 11 - Bulletin No. 346060)).

In this regard, there is known a technique for improving the laser processability of ultra-thin copper foil by controlling the cross-sectional size of copper crystal grains constituting ultra-thin copper foil to a specific value or less. For example, Patent Document 2 (Japanese Patent Laid-Open No. 2017-133105) discloses a copper foil with a carrier, which when observed with FIB-SIM (Focused Ion Beam-Scanning ion Microscope, focused ion beam-scanning ion microscope) The average crystal grain size of the cross-sectional image of the ultra-thin copper layer is controlled below 0.5 μm. It is believed that the laser opening and etching properties can be improved by the copper foil with a carrier. In addition, Patent Document 3 (Japanese Patent No. 6158573) also discloses a copper foil with a carrier. In order to improve the laser opening property, etc., the thickness accuracy of the ultra-thin copper layer measured by the weight thickness method is 3.0 % or less, and the average crystal grain size is controlled below 0.5 μm when the cross-sectional image of the ultra-thin copper layer is observed with FIB-SIM. [Prior technical literature] [Patent literature]

[Patent Document 1] Japanese Patent Laid-Open No. 11-346060 [Patent Document 2] Japanese Patent Laid-Open No. 2017-133105 [Patent Document 3] Japanese Patent No. 6158573

In recent years, the high integration of printed wiring boards, the miniaturization of wiring and the miniaturization of through holes have further developed. Therefore, further improvement in laser processability (through-hole processability) is required for ultra-thin copper foil. However, the laser processability of the ultra-thin copper foil in the conventional copper foil with a carrier is not necessarily sufficient, and there is still room for improvement.

This time, the inventors of the present invention obtained the following insight: by making the copper crystals present on the surface of the ultra-thin copper foil on the side of the release layer in the copper foil with a carrier sequentially provided The planar size of the grains is controlled within a specific range to achieve excellent laser processability.

Therefore, the object of this invention is to provide the copper foil with a carrier which can realize the outstanding laser processability.

According to one aspect of the present invention, there is provided a copper foil with a carrier, which has a carrier, a release layer, and an ultra-thin copper foil in sequence, and the presence of the ultra-thin copper foil measured by electron backscatter diffraction (EBSD) in the above-mentioned ultra-thin copper foil is provided. The planar size S1 _of the copper crystal grains on the surface of the copper foil on the side of the peeling layer is 50 nm or more and 600 nm or less.

According to another aspect of the present invention, there is provided a copper foil laminate comprising: a copper foil with a carrier, which is sequentially provided with a carrier, a release layer, and an ultra-thin copper foil; and a resin layer provided on the copper foil with a carrier. On the surface of the ultra-thin copper foil of the foil, the planar size S1 _of the copper crystal grains present on the surface of the above-mentioned peeling layer side of the above-mentioned ultra-thin copper foil measured by electron backscatter diffraction (EBSD) is 50 nm Above 600 nm and below.

According to another aspect of this invention, the printed wiring board provided with the said copper foil with a carrier is provided.

According to still another aspect of the present invention, there is provided a method of manufacturing a printed wiring board, characterized in that the printed wiring board is manufactured using the above-mentioned copper foil with a carrier.

Copper foil with a carrier The copper foil with a carrier of this invention is equipped with a carrier, a peeling layer, and an ultra-thin copper foil in this order. The copper foil with a carrier has a planar size S ₁ of copper crystal grains present on the surface of the peeling layer side of the ultra-thin copper foil measured by electron backscatter diffraction (EBSD), which is 50 nm or more and 600 nm or less. By controlling the planar size of the copper crystal grains existing on the surface of the peeling layer side of the ultra-thin copper foil within a specific range in this way, excellent laser processability can be realized.

Here, a schematic cross-sectional view of a laminate produced using the copper foil with a carrier of the present invention is shown in FIG. 1 . The laminated body 18 shown in FIG. 1 is equipped with the ultra-thin copper foil 12 derived from the copper foil with a carrier of this invention, and the resin layer 16. Moreover, the roughening particle 14 adheres to the surface of the resin layer 16 side of the ultra-thin copper foil 12 as needed. The surface of the laminate 18 on the side of the ultra-thin copper foil 12 (that is, the surface opposite to the resin layer 16) is the surface that is irradiated by the laser L (such as carbon dioxide laser) during laser processing, which is equivalent to the surface of the copper foil with the carrier. The surface on the release layer side of the ultra-thin copper foil 12 in the foil. On the other hand, the surface of the ultra-thin copper foil 12 on the side of the resin layer 16 in the laminate 18 (that is, the surface opposite to the surface irradiated with the laser L) corresponds to the peeling of the ultra-thin copper foil 12 of the copper foil with a carrier. The surface on the opposite side of the layer (the surface on the side of the roughened particle 14 when the roughened particle 14 exists).

The mechanism by which the copper foil with a carrier of this invention can realize the excellent laser processability is not necessarily clear, For example, the following is mentioned. That is, in order to easily form via holes in ultra-thin copper foil by laser processing, it is necessary to suppress heat diffusion and raise the temperature of ultra-thin copper foil in a short time. In this regard, it is considered that by reducing the crystal size of the copper crystal grains constituting the ultra-thin copper foil, the number of grain boundaries per unit area is increased, which hinders heat conduction, so the temperature of the ultra-thin copper foil is easy to rise. _In particular, the inventors _of the present invention conducted studies and found that, as shown in FIG. It is more effective for finer through-hole processing. Furthermore, it was found that by setting the planar size S1 _of the copper crystal grains _G1 existing on the surface of the peeling layer side of the ultra-thin copper foil 12 in the copper foil with a carrier within the above-mentioned specific range, excellent laser radiation can be realized. Processability. On the other hand, since the previous copper foil with a carrier only controls the crystal size in the cross-sectional direction (z-axis direction) of the ultra-thin copper foil, as mentioned above, the laser processability of the ultra-thin copper foil is not necessarily sufficient.

Therefore, in the copper foil with carrier, the planar size S ₁ of the copper crystal grains G ₁ present on the surface of the peeling layer side of the ultra-thin copper foil 12 measured by EBSD is 50 nm to 600 nm, preferably 70 nm. nm to 600 nm, more preferably 80 nm to 400 nm, further preferably 80 nm to 300 nm. Furthermore, since the copper crystal grains constituting the ultra-thin copper foil 12 are recrystallized by hot pressing when bonding with the resin, the crystal size may change. In this regard, the planar dimension S1 refers to the planar crystal size (average crystal grain size) after the copper foil with _a carrier is bonded to the resin. Specifically, the plane dimension S1 refers to the value _of the following situation: at 220°C and a pressure of 4.0 MPa, a resin sheet (such as a prepreg) is pressed on the surface of the ultra-thin copper foil with carrier copper foil 12 side After 90 minutes, the resin layer 16 is formed, and the carrier and the peeling layer are peeled off together to form a laminate 18 with an ultra-thin copper foil 12 and a resin layer 16 as shown in Figure 1, and then the electrodes of the laminate 18 are aligned by EBSD The surface on the side of the thin copper foil 12 (that is, the surface on the side of the peeling layer of the ultra-thin copper foil 12 in the copper foil with carrier) is analyzed. Calculation _of the planar dimension S1 can be preferably carried out according to the procedure shown in the evaluation (8b) of the embodiment described later. Furthermore, regarding the measurement conditions of the scanning electron microscope shown in the examples, the observation magnification, measurement range, current value, and step can be appropriately changed according to the size of crystal grains.

In the copper foil with carrier, the cross-sectional size S2 of the copper crystal grains constituting the ultra-thin copper foil 12 measured by EBSD is preferably from ₂₀₀ nm to 600 nm, more preferably from 300 nm to 400 nm, and even more preferably It is between 350 nm and 400 nm. That is, in order to efficiently form via holes by laser processing, it is necessary to conduct heat conduction to a certain extent in the cross-sectional direction (z-axis direction) of the ultra-thin copper foil 12 . On the other hand, in order not to diffuse heat excessively, it is preferable that the crystal size of the cross-sectional direction (z-axis direction) of the copper crystal grains be small. Therefore, by making the cross-sectional dimension S2 of the copper crystal grain which comprises the ultra-thin copper foil ₁₂ into the said range, the laser processability of an ultra-thin copper foil can be improved further. Also, the cross _- sectional dimension S2 refers to the cross-sectional crystal size (average crystal grain size) after the copper foil with a carrier is bonded to the resin. Specifically, the cross _- sectional dimension S2 refers to the value of the following situation: the laminated body 18 is produced under the same conditions as the calculation of the above _- mentioned planar dimension S1, and then the laminated body 18 is compared by the electron backscatter diffraction method (EBSD). Analysis of the cross-section in the thickness direction of the medium-ultra-thin copper foil 12. _The calculation of the cross-sectional dimension S2 can be preferably carried out according to the procedure shown in the evaluation (8d) of the embodiment described later.

In the copper foil with carrier, the _ratio of the above _- mentioned cross _- sectional dimension S2 to the above _- mentioned planar dimension S1, that is, S2/S1, is preferably from 0.7 to 6.0, more preferably from 1.0 to 5.0, further preferably from 1.7 to 3.0 . Thereby, the temperature rise of the ultra-thin copper foil and the heat conduction to the cross-sectional direction can be realized in a balanced manner when the laser L is irradiated, and the laser processability can be further improved.

In the copper foil with carrier, the copper crystal grains existing on the surface of the ultra-thin copper foil 12 opposite to the peeling layer (the surface on the side of the roughened particle 14 in the case where the roughened particle 14 exists) measured by EBSD _The plane size S3 _of G3 is preferably from 100 nm to 600 nm, more preferably from 100 nm to 500 nm, further preferably from 100 nm to 400 nm, still more preferably from 100 nm to 300 nm, especially Preferably, it is not less than 100 nm and not more than 200 nm, most preferably not less than 100 nm and not more than 150 nm. That is, the crystal grains of the ultra-thin copper foil 12 tend to increase in size as the thickness increases, but it is desirable that the crystal grains are not excessively coarse. Therefore, as shown in FIG. 1 , it is desirable to peel off the ultra-thin copper foil 12 in the copper foil with carrier on the side of the resin layer 16 that constitutes the ultra-thin copper foil 12 (that is, the surface opposite to the side irradiated with the laser L). The planar size S3 _of the copper grain G3 _on the opposite side of the layer is also smaller. Therefore, in the copper foil with a carrier, by setting the planar size S3 _of the copper crystal grain G3 existing _on the surface opposite to the release layer of the ultra-thin copper foil 12 within the above-mentioned range, it is possible to irradiate with the laser L. At this time, the ultra-thin copper foil 12 can be heated more effectively, and the laser processability can be further improved. _In addition, the plane size S3 means the plane crystal size (average crystal grain size) after bonding the copper foil with a carrier and the resin. Specifically, the plane dimension S3 refers to the value _of the following situation: the laminated body 18 is produced under the same conditions as the calculation of the above _- mentioned plane dimension S1, and then the back surface of the ultra-thin copper foil 12 in the laminated body 18 is subjected to EBSD. The case of analysis. Here, the back surface of the ultra-thin copper foil 12 refers to the surface at a position 0.1 μm shallower than the thickness of the ultra-thin copper foil 12 described later from the surface of the laminate 18 on the ultra-thin copper foil 12 side in the depth direction. Calculation _of the planar dimension S3 can be preferably carried out according to the procedure shown in the evaluation (8c) of the embodiment described later.

The thickness of the ultra-thin copper foil 12 is preferably 2.0 μm or less, more preferably 0.3 μm or more and 1.2 μm or less, still more preferably 0.3 μm or more and 1.0 μm or less, especially preferably 0.3 μm or more and 0.8 μm or less. Thereby, it is easy to control the planar dimension _{S 1} , the cross-sectional dimension S ₂ , and the planar dimension S3 within the above-mentioned specific ranges, and as a result, the laser processability can be further effectively improved. Furthermore, when the copper foil with a carrier further has a roughened layer including a plurality of roughened particles 14, the thickness of the ultra-thin copper foil 12 does not include the thickness of the roughened layer. The measurement of the thickness of the ultra-thin copper foil 12 can be preferably carried out by using any one of the following (i) and (ii) methods after producing the laminate 18 under the same conditions as the calculation _of the planar dimension S1, for example. (i) Using a focused ion beam-scanning electron microscope (FIB-SEM), observe the cross section of the laminated body 18 . In the analysis of this cross section, as shown in FIG. 2 , a line A passing through the most concave portion 14 a of the roughened particles and parallel to the average plane of the ultra-thin copper foil surface 12 a is drawn. Thereafter, a line segment B perpendicular to the line A is drawn from the most concave portion 14a of the roughened particles toward the surface 12a of the ultra-thin copper foil. The distance until the line segment B contacts the ultra-thin copper foil surface 12 a is calculated, and this is taken as the thickness of the ultra-thin copper foil 12 . (ii) From the ultra-thin copper foil 12 side of the laminated body 18, planar polishing using a cross-section polisher (CP) is performed. Based on the polishing rate measured in advance, the polishing depth at which the surface polishing process is continued so that the resin layer 16 starts to expose a part of the laminate 18 is calculated, and this is taken as the thickness of the ultra-thin copper foil 12 . Whether or not the resin layer 16 is exposed can be determined by observing the processed surface of the laminate 18 at a low magnification (for example, about 1000 times) using a scanning electron microscope (SEM).

If necessary, the surface of the ultra-thin copper foil 12 may be roughened to form a roughened layer. By providing the roughened layer on the ultra-thin copper foil 12, the adhesiveness with the resin layer 16 can be improved at the time of manufacturing a copper foil laminated board or a printed wiring board. The roughened layer has a plurality of roughened particles 14 (round blocks), and each of the plurality of roughened particles 14 preferably includes copper particles. Copper particles may contain metallic copper or may contain a copper alloy. The roughening treatment for forming the roughened surface can be preferably performed by forming the roughening particles 14 on the ultra-thin copper foil 12 with copper or copper alloy. For example, it is preferable to carry out the roughening treatment according to the plating method, which includes a firing plating step of depositing fine copper particles and adhering to the ultra-thin copper foil 12, and a cover for preventing the fine copper particles from falling off. At least two plating steps of the plating steps.

Anti-rust treatment can also be performed on the surface of the ultra-thin copper foil 12 as needed to form an anti-rust treatment layer. The antirust treatment preferably includes plating treatment using zinc. The plating treatment using zinc may be any of zinc plating treatment and zinc alloy plating treatment, and zinc alloy plating treatment is particularly preferably zinc-nickel alloy treatment. The zinc-nickel alloy treatment may be a plating treatment including at least Ni and Zn, and may further include other elements such as Sn, Cr, and Co. The Ni/Zn adhesion ratio in zinc-nickel alloy plating is preferably from 1.2 to 10 in mass ratio, more preferably from 2 to 7, and still more preferably from 2.7 to 4. Moreover, it is preferable that antirust treatment further includes chromate treatment, and it is more preferable that this chromate treatment is performed on the plating surface containing zinc after the plating treatment using zinc. Thereby, rust resistance can be further improved. A particularly preferred antirust treatment is a combination of zinc-nickel alloy plating followed by chromate treatment.

Alternatively, the surface of the ultra-thin copper foil 12 may be treated with a silane coupling agent to form a silane coupling agent layer. Thereby, moisture resistance, chemical resistance, and adhesiveness with an adhesive etc. can be improved. The silane coupling agent layer can be formed by appropriately diluting and applying the silane coupling agent, and drying it. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane and 3-glycidyloxypropyltrimethoxysilane; 3-aminopropyl Trimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-3-(4-(3-aminopropoxy)butoxy)propyl- Amino-functional silane coupling agents such as 3-aminopropyltrimethoxysilane and N-phenyl-3-aminopropyltrimethoxysilane; mercapto-functional silane coupling agents such as 3-mercaptopropyltrimethoxysilane Mixture; olefin functional silane coupling agents such as vinyltrimethoxysilane and vinylphenyltrimethoxysilane; acrylic functional silane coupling agents such as 3-methacryloxypropyl trimethoxysilane; imidazole silane Imidazole-functional silane coupling agent; or tri-sulfone-functional silane coupling agent such as tri-sulfone silane, etc.

Therefore, the copper foil with a carrier is preferably provided with at least one selected from the group consisting of a roughened layer containing a plurality of roughened particles 14, an antirust treatment layer, and a silane coupling agent layer on the ultra-thin copper foil 12. Floor. For example, when the copper foil with a carrier is further equipped with a roughening layer, an anti-rust treatment layer, and a silane coupling agent layer, the order of these layers is not particularly limited, and it is preferable to place them sequentially on the ultra-thin copper foil 12. Laminated roughening layer, anti-rust treatment layer, and silane coupling agent layer.

Copper foil with a carrier has a carrier. The carrier system is used to support the ultra-thin copper foil to improve its handling. A typical carrier includes a metal layer. Examples of such a carrier include aluminum foil, copper foil, stainless steel (SUS) foil, resin film or glass obtained by metal-coating the surface with copper or the like, and copper foil is preferred. The copper foil may be any one of rolled copper foil and electrolytic copper foil, preferably electrolytic copper foil. The thickness of the carrier is typically not more than 250 μm, preferably not less than 7 μm and not more than 200 μm.

The copper foil with carrier has a release layer on the carrier. The release layer is a layer that has the following functions: weaken the peel strength of the carrier, ensure the stability of the strength, and inhibit the interdiffusion that may occur between the carrier and the copper foil during press forming at high temperature. The release layer is usually formed on one side of the carrier, but may be formed on both sides. The peeling layer may be any one of an organic peeling layer and an inorganic peeling layer. As an example of the organic component used for an organic release layer, a nitrogen-containing organic compound, a sulfur-containing organic compound, a carboxylic acid, etc. are mentioned. As an example of a nitrogen-containing organic compound, a triazole compound, an imidazole compound, etc. are mentioned, Among these, a triazole compound is preferable at the point which peelability is easy to stabilize. Examples of triazole compounds include: 1,2,3-benzotriazole, carboxybenzotriazole, N',N'-bis(benzotriazolylmethyl)urea, 1H-1, 2,4-triazole, and 3-amino-1H-1,2,4-triazole, etc. Examples of sulfur-containing organic compounds include mercaptobenzothiazole, thiocyanuric acid, and 2-benzimidazolethiol. As an example of a carboxylic acid, a monocarboxylic acid, a dicarboxylic acid, etc. are mentioned. On the other hand, Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, chromate treatment film, etc. are mentioned as an example of the inorganic component used for an inorganic peeling layer. The thickness of the release layer is typically not less than 1 nm and not more than 1 μm, preferably not less than 5 nm and not more than 500 nm.

Other functional layers may also be provided between the release layer and the carrier and/or the ultra-thin copper foil 12 . As an example of such another functional layer, an auxiliary metal layer may be mentioned. The auxiliary metal layer preferably includes nickel and/or cobalt. By forming such an auxiliary metal layer on the surface side of the carrier and/or on the surface side of the ultra-thin copper foil 12, it is possible to further suppress the possibility of being trapped between the carrier and the ultra-thin copper foil 12 during high-temperature or long-term thermocompression forming. The resulting interdiffusion ensures the stability of the peel strength of the carrier. The thickness of the auxiliary metal layer is preferably not less than 0.001 μm and not more than 3 μm.

Manufacturing method of copper foil with carrier The copper foil with carrier of the present invention can be manufactured by the following methods: (1) preparing a carrier; (2) forming a peeling layer on the carrier; (3) forming an ultra-thin copper foil on the peeling layer. Hereinafter, an example of a preferable manufacturing method of the copper foil with a carrier of this invention is demonstrated.

(1) Preparation of carrier First, a carrier as a support is prepared. A typical carrier includes a metal layer. Examples of such a carrier include, as mentioned above, aluminum foil, copper foil, stainless steel (SUS) foil, resin film or glass obtained by metal-coating the surface with copper or the like, and copper foil is preferred. The copper foil may be any one of rolled copper foil and electrolytic copper foil, preferably electrolytic copper foil. The thickness of the carrier is typically not more than 250 μm, preferably not less than 7 μm and not more than 200 μm.

The surface of the carrier on the release layer side is preferably smooth. That is, in the manufacturing process of the copper foil with a carrier, the ultra-thin copper foil 12 is formed on the surface of the carrier on the release layer side. Therefore, by smoothing the surface of the carrier on the side of the peeling layer in advance, the outer surface of the ultra-thin copper foil 12 can also be smoothed, and the crystal growth surface of the ultra-thin copper foil 12 can be easily made uniform. As a result, an ultra-thin copper foil containing copper crystal grains having a desired crystal size can be easily obtained. The surface of the release layer side of the carrier can be smoothed, for example, by polishing the surface of the cathode used for electrolytically foiling the carrier with a specific number of buffs to adjust the surface roughness. That is, by transferring the surface profile of the cathode adjusted in this way to the electrode surface of the carrier, an ultra-thin copper foil is formed on the electrode surface of the carrier with a peeling layer interposed therebetween, thereby easily forming the above-mentioned cathode containing a specific crystal size. Ultra-thin copper foil with copper grains. The preferred number of polishing wheels is above #1,000 and below #3,500, more preferably above #1,000 and below #2,500. In addition, from the point of view that it is easier to control the crystal size of the copper crystal grains constituting the ultra-thin copper foil to the desired range, the deposition surface side of the carrier obtained by electrolytic foil production using an electrolyte solution containing additives can also be used as The surface of the release layer side of the carrier.

(2) Formation of peeling layer A peeling layer is formed on the carrier. The peeling layer may be any one of an organic peeling layer and an inorganic peeling layer. Preferred examples of the organic release layer and the inorganic release layer are as described above. The release layer can be formed by the following methods: making the solution containing the release layer components contact at least one surface of the carrier, and fixing the release layer components on the surface of the carrier. When the carrier is brought into contact with the solution containing the release layer components, the contact is carried out by immersion in the solution containing the release layer components, spraying the solution containing the release layer components, flowing down the solution containing the release layer components, etc. Can. In addition, a method of forming a coating film of the release layer components by a gas phase method such as vapor deposition or sputtering may also be employed. Also, the release layer components can be fixed on the carrier surface by adsorption or drying of a solution containing the release layer components, electrodeposition of the release layer components in a solution containing the release layer components, or the like. The thickness of the release layer is typically not less than 1 nm and not more than 1 μm, preferably not less than 5 nm and not more than 500 nm.

(3) Formation of Ultra-Thin Copper Foil An ultra-thin copper foil 12 is formed on the release layer. For example, the ultra-thin copper foil 12 can be formed by wet film-forming methods such as electroless copper plating and electrolytic copper plating, dry film-forming methods such as sputtering and chemical vapor deposition, or a combination thereof. Preferably, the ultra-thin copper foil 12 is formed by electrolytic copper plating. In particular, from the viewpoint of controlling the early precipitation of the ultra-thin copper foil and reducing the crystal grain size, it is preferable to set the conditions at the time of electrolytically producing the ultra-thin copper foil 12 as follows. That is, the copper concentration is set to 40 g/L to 80 g/L (more preferably 50 g/L to 70 g/L), and the sulfuric acid concentration is set to 180 g/L to 260 g/L (more preferably preferably 200 g/L or more and 250 g/L or less), adjust the concentration of carboxybenzotriazole (CBTA) as an additive to more than 0 ppm and less than 200 ppm, use the obtained sulfuric acid-based copper electrolyte, and use DSA ( Dimensional Stability Anode) as the anode, at a liquid temperature above 35°C and below 60°C (more preferably above 40°C and below 55°C), with a current density above 3 A/dm ² and below 60 A/dm ² (preferably 5 A/dm 2 dm ² to 35 A/dm ² , and more preferably 6 A/dm ² to 30 A/dm ² ), electrolysis is carried out under the conditions, so that the required electrolytic copper foil can be obtained preferably. The concentration of CBTA in the electrolyte is more preferably from 0.1 ppm to 100 ppm, more preferably from 0.1 ppm to 50 ppm, especially preferably from 0.1 ppm to 30 ppm, most preferably from 0.1 ppm to 10 ppm. By adding carboxybenzotriazole (CBTA) as an additive to the electrolytic solution in this way, and controlling the current density within the above-mentioned range to perform electrolytic foil production, it is easy to form the above-mentioned ultra-thin copper crystal grains with a specific crystal size. Copper foil12.

If necessary, the surface of the ultra-thin copper foil can be subjected to roughening treatment, antirust treatment and/or silane coupling agent treatment to form a roughening layer, antirust treatment layer, and/or silane coupling agent containing a plurality of roughened particles Floor. Such processing is described above.

Copper foil laminated board It is preferable that the copper foil with a carrier of this invention is used for manufacturing the copper foil laminated board for printed wiring boards. That is, according to a preferable aspect of this invention, the copper foil laminated board provided with the said copper foil with a carrier is provided. Copper foil laminates include: copper foil with carrier, which is sequentially provided with carrier, release layer, and ultra-thin copper foil; and resin layer, which is provided on the surface of the ultra-thin copper foil of the copper foil with carrier (ultra-thin copper the side opposite to its release layer). In this copper foil laminate, the planar size of the copper crystal grains present on the side of the release layer (the side opposite to the resin layer) of the ultra-thin copper foil measured by electron backscatter diffraction (EBSD) S ₁ is not less than 50 nm and not more than 600 nm. The preferred aspects of the above-mentioned copper foil with a carrier are also directly applicable to the copper foil with a carrier included in the copper foil laminate. Copper foil with carrier can be installed on one side of the resin layer or on both sides. The resin layer contains resin, preferably insulating resin. The resin layer is preferably a prepreg and/or a resin sheet. Prepreg system is a general term for composite materials made by impregnating synthetic resin in synthetic resin boards, glass boards, glass woven fabrics, glass non-woven fabrics, paper and other substrates. Preferable examples of insulating resins include epoxy resins, cyanate resins, bismaleimide tristannium resins (BT resins), polyphenylene ether resins, and phenolic resins. Moreover, examples of the insulating resin constituting the resin sheet include insulating resins such as epoxy resins, polyimide resins, and polyester resins. In addition, filler particles including various inorganic particles such as silica and alumina may be contained in the resin layer from the viewpoint of improving insulation. The thickness of the resin layer is not particularly limited, but is preferably from 1 μm to 1000 μm, more preferably from 2 μm to 400 μm, and still more preferably from 3 μm to 200 μm. The resin layer may contain a plurality of layers. Resin layers such as prepregs and/or resin sheets can also be provided on the copper foil with carrier through the primer resin layer coated on the surface of the ultra-thin copper foil in advance.

Printed Wiring Board The copper foil with a carrier of the present invention is preferably used in the production of printed wiring boards. That is, according to a preferable aspect of this invention, the printed wiring board provided with the said copper foil with a carrier, or its manufacturing method is provided. The printed wiring board of this aspect is comprised including the layer which laminated|stacked the resin layer and the copper layer sequentially. In addition, the resin layer is as described above about the copper foil laminated board. In any case, the printed wiring board can be constructed using known layers. As a specific example related to printed wiring boards, one side obtained by bonding the ultra-thin copper foil of the present invention to one or both sides of a prepreg and hardening it to form a laminate, and then forming a circuit on one side Or double-sided printed wiring boards; or multilayer printed wiring boards made by multilayering them. Also, as other specific examples, a flexible printed wiring board in which the ultra-thin copper foil of the present invention is formed on a resin film to form a circuit, COF (Chip On Film), TAB (Tape Automated Bonding, Tape type automatic splicing) Tape, etc. As another specific example, the above-mentioned resin layer is coated on the ultra-thin copper foil of the present invention to form a resin-coated copper foil (RCC), and the resin layer is laminated on the above-mentioned printed wiring board as an insulating adhesive material, and then Ultra-thin copper foil is used as all or part of the wiring layer, and the circuit is formed by the modified semi-additive method (MSAP), subtractive method, etc. A build-up wiring board obtained by forming a circuit using the SAP method; or a direct build-up wafer with resin-attached copper foil and a circuit formed on a semiconductor integrated circuit alternately and repeatedly. The copper foil with a carrier of the present invention can also be preferably used in a so-called coreless build-up method in which insulating resin layers and conductor layers are alternately laminated without using a core substrate. [Example]

The present invention is further specifically described by the following examples.

Examples 1-4 and 6-11 produced and evaluated the copper foil with a carrier provided with the roughening process copper foil as follows .

(1) Preparation of carrier Regarding examples 1, 3, 4, and 6-11, use a copper electrolyte solution having the composition shown below, a cathode, and DSA (dimensionally stable anode) as an anode at a solution temperature of 50°C , Electrolyzed under the condition of current density 70 A/dm ² , to obtain an electrolytic copper foil with a thickness of 18 μm as a carrier. At this time, as a cathode, an electrode whose surface was polished with a buff of the number shown in Table 1 and whose surface roughness was adjusted was used. ＜Composition of copper electrolyte＞ ‐Copper concentration: 80 g/L ‐Sulfuric acid concentration: 300 g/L ‐Chlorine concentration: 30 mg/L ‐Gel concentration: 5 mg/L

Regarding Example 2, a sulfuric acid copper sulfate solution having the composition shown below was used as the copper electrolytic solution. Then, use an electrode with a surface roughness Ra of 0.20 μm as the cathode, use DSA (dimensionally stable anode) as the anode, and perform electrolysis at a solution temperature of 45°C and a current density of 55 A/dm ² to obtain a thickness of 18 μm The electrolytic copper foil is used as the carrier. ＜Composition of sulfuric acid acidic copper sulfate solution＞ - Copper concentration: 80 g/L - Sulfuric acid concentration: 260 g/L - Bis(3-sulfopropyl) disulfide concentration: 30 mg/L - Diallyl dimethyl Ammonium Chloride Polymer Concentration: 50 mg/L ‐ Chlorine Concentration: 40 mg/L

(2) Formation of peeling layer Regarding Examples 1, 3, 4, and 6 to 11, the electrode surface of the acid-washed carrier was mixed with carboxybenzotriazole (CBTA) concentration of 1 g/L and sulfuric acid concentration of 150 g at a liquid temperature of 30°C. /L, and a CBTA aqueous solution with a copper concentration of 10 g/L for 30 seconds, so that the CBTA component is adsorbed on the electrode surface of the carrier. In this way, a CBTA layer is formed on the electrode surface of the carrier as an organic release layer. Also, regarding Example 2, the CBTA layer was formed by adsorbing the CBTA component on the precipitation surface instead of the electrode surface of the carrier, and the organic release layer was formed in the same manner as in Examples 1, 3, 4, and 6-11. .

(3) Formation of the auxiliary metal layer. Immerse the carrier with the organic peeling layer in a solution containing nickel concentration of 20 g/L made of nickel sulfate. Under the condition of dm ² , nickel is deposited on the organic release layer in an amount corresponding to a thickness of 0.001 μm. In this way, a nickel layer is formed on the organic release layer as an auxiliary metal layer.

(4) Formation of ultra-thin copper foil. Immerse the carrier with the auxiliary metal layer in the copper solution with the composition shown below, at a solution temperature of 50°C and a current density of ⁵ A/dm2 or more and 40 ^A /dm2 or less. Electrolysis is carried out under certain conditions to form an ultra-thin copper foil with a specific thickness on the auxiliary metal layer. ＜Solution composition＞ ‐Copper concentration: 60 g/L ‐Sulfuric acid concentration: 200 g/L ‐CBTA concentration: as shown in Table 1.

(5) Roughening process Roughening process copper foil was formed by roughening the surface of the ultra-thin copper foil formed in this way, and the copper foil with a carrier was obtained by this. The roughening treatment includes a burn-plating step for depositing fine copper particles and adhering to the ultra-thin copper foil, and a cover plating step for preventing the fine copper particles from falling off. In the firing plating step, the concentration of 9-phenylacridine (9PA) reaches 60 ppm, and the concentration of chlorine reaches 50 ppm. 9PA and chlorine were added to the copper solution, and the roughening treatment was carried out at a current density of 20 A/dm ² . In the subsequent cover plating step, use an acidic copper sulfate solution containing a copper concentration of 70 g/L and a sulfuric acid concentration of 240 g/L, under the smooth plating conditions of a liquid temperature of 52°C and a current density of 15 A/dm ² Electrodeposition.

(6) Antirust treatment The roughened surface of the obtained copper foil with a carrier was subjected to antirust treatment including zinc-nickel alloy plating treatment and chromate treatment. First, use a solution containing zinc concentration of 1 g/L, nickel concentration of 2 g/L, and potassium pyrophosphate concentration of 80 g/L to roughen the layer at a liquid temperature of 40°C and a current density of 0.5 ^A /dm2 And the surface of the carrier is treated with zinc-nickel alloy plating. Secondly, using an aqueous solution containing 1 g/L of chromic acid, under the conditions of pH value 12 and current density 1 A/dm ² , chromate treatment was performed on the zinc-nickel alloy plated surface.

(7) Silane coupling agent treatment The aqueous solution containing a commercially available silane coupling agent is adsorbed on the surface of the roughened copper foil side of the copper foil with a carrier, and the water is evaporated with an electric heater to perform the silane coupling agent treatment. At this time, the silane coupling agent treatment was not performed on the carrier side.

(8) Evaluation The evaluation of various characteristics was performed as follows about the copper foil with a carrier obtained in this way.

(8a) Fabrication of laminated body Using the obtained copper foil with a carrier, the laminated body 18 shown in FIG. 1 was produced as follows. First, a prepreg (manufactured by Mitsubishi Gas Chemical Co., Ltd., GHPL-830NX-A) having a thickness of 0.10 mm was prepared. The obtained copper foil with a carrier was laminated on the prepreg so that the roughened surface (the surface on the side of the roughened particles 14) was in contact with the prepreg, and the process was carried out at a temperature of 220°C and a pressure of 4.0 MPa. The pressure was applied for 90 minutes, whereby the resin layer 16 was formed. Thereafter, the laminate 18 including the ultra-thin copper foil 12 and the resin layer 16 is obtained by peeling and removing the carrier together with the release layer. The laminated body 18 was cross-sectionally observed using a focused ion beam-scanning electron microscope (FIB-SEM), and the thickness of the ultra-thin copper foil 12 (without roughening particles 14 ) was measured in advance. In the analysis of this section, first, as shown in FIG. 2 , a line A passing through the most concave portion 14a of the roughened particles and parallel to the average plane of the ultra-thin copper foil surface 12a is drawn. Next, a line segment B perpendicular to line A is drawn from the most concave portion 14a of the roughened particles toward the surface 12a of the ultra-thin copper foil. Then, the distance until the line segment B contacts the ultra-thin copper foil surface 12 a is calculated, and this is taken as the thickness of the ultra-thin copper foil 12 . Table 1 shows the thickness of the ultra-thin copper foil 12 in each example.

(8b) Measurement of planar crystal size on the surface of the ultra-thin copper foil Using the laminate 18 obtained in (8a) above, measure the crystal size present on the outermost surface of the ultra-thin copper foil 12 (that is, the electrode in the copper foil with a carrier) in the following manner. The plane size S ₁ of the copper crystal grain G ₁ of the thin copper foil 12 on the side of the release layer). Firstly, the laminated body 18 is fixed on the aluminum stub with an adhesive, and then the carbon paste is applied to the peripheral portion of the laminated body 18 to determine the observation position and ensure the conduction. Thereafter, surface polishing by a cross-section polisher (CP) was performed from the ultra-thin copper foil 12 side of the laminated body 18 . This planar polishing was carried out under conditions of an accelerating voltage of 3 kV and an inclination angle of 10°. Then, the ultra-thin copper foil 12-side surface of the laminate 18 after planar polishing for 5 minutes (corresponding to a thickness of 50 nm) was used as the outermost surface of the ultra-thin copper foil 12 for marking and FIB marking processing.

Using an FE (Field Emission, Field Emission) gun-type scanning electron microscope (manufactured by Carl Zeiss AG, Crossbeam 540) equipped with an EBSD detector (manufactured by Oxford Instruments, Symmetry), the best results for this ultra-thin copper foil 12 Observe the surface. Then, EBSD data were obtained using EBSD measurement software (manufactured by Oxford Instruments, AZtec5.0 HF1), and the obtained EBSD data were converted into an OIM (Orientation Imaging Microscopy) format. The measurement conditions of the scanning electron microscope at the time of observation are as follows. ＜Scanning Electron Microscope Measurement Conditions＞ ‐Acceleration voltage: 15 kV ‐Stride: 22.9 nm ‐Area width: 5.86 μm ‐Area height: 4.4 μm ‐Scan Phase (Scan Phase): Cu ‐Sample angle: 70°

Based on the data converted into the above-mentioned OIM format, the crystal distribution is measured using crystal diameter calculation software (manufactured by AMETEK, OIM Analysis v7.3.1 x64), and the planar size of the copper crystal grain _G1 present on the outermost surface of the ultra-thin copper foil 12 is calculated. S ₁ (average grain size, "Grain Size-Average Area" on the software). The results are shown in Table 1. In addition, in the measurement of crystal distribution, an orientation difference of 5° or more is regarded as a grain boundary. However, since the crystal structure of copper is a cubic crystal structure, it is not regarded as a grain boundary in the case of the following (i) or (ii) in consideration of twin grain boundaries. (i) There is a twin grain boundary with an azimuth relationship that rotates 60° around the axis <111> (ii) There is a twin grain boundary with an azimuth relationship that rotates 38.9° around the axis <110>

(8c) Measurement of the plane crystal size of the back surface of the ultra-thin copper foil Next, measure the back surface of the ultra-thin copper foil 12 (that is, the side opposite to the release layer of the ultra-thin copper foil 12 in the copper foil with a carrier) as follows The plane size S ₃ of the copper grain G ₃ of the surface). First, for the laminated body ₁₈ after measuring the plane dimension S1 in (8b) above, continue plane polishing with a cross-section polisher (CP) from the marked position (the outermost surface) of the ultra-thin copper foil 12 . This surface polishing is performed until the back surface of the ultra-thin copper foil 12 is reached. Furthermore, the back surface of the ultra-thin copper foil 12 is the surface at a position 0.1 μm shallower than the thickness of the ultra-thin copper foil 12 measured in (8a) above in the depth direction from the outermost surface of the ultra-thin copper foil 12 . Thereafter, in the same manner as above (8b), calculate the plane size _{S 3 (} average grain size, "Grain Size-Average Area( Particle size - average area)" item). The results are shown in Table 1.

(8d) Measurement of cross-sectional crystal size Using the laminate 18 obtained in the above (8a), the cross-sectional size S ₂ of the copper crystal grains constituting the ultra-thin copper foil 12 was measured as follows. First, cross-section processing was performed from the surface of the laminated body 18 on the ultra-thin copper foil 12 side to the thickness direction with a cross-section polisher (CP) under the condition of an accelerating voltage of 5 kV. Then, for the cross-section of the ultra-thin copper foil 12, except for changing the measurement conditions of the scanning electron microscope as described below, the cross-sectional dimension S of the copper crystal grains constituting the ultra-thin copper foil 12 was calculated in the same manner as in (8b) above. ₂ (Average crystal size, "Grain Size-Average Area" item on the software). The results are shown in Table 1. <Scanning Electron Microscope Measurement Conditions> - Accelerating Voltage: 10.00 kV - Step: 10 nm - Domain Width: 5.86 μm - Domain Height: 4.4 μm - Scan Phase: Cu - Sample Angle: 70°

(8e) Laser processability evaluation Using the laminate 18 obtained in (8a) above, laser processability evaluation was performed as follows. First, a carbon dioxide laser was used to laser process the surface of the laminate 18 on the ultra-thin copper foil 12 side under the conditions of a beam diameter of 86 μm and a pulse width of 12 μs to form 121 through holes. The formed through holes were observed from the ultra-thin copper foil 12 side with a metallographic microscope. At this time, the 33 holes in the initial stage of processing will not be evaluated because deviations will occur. For the remaining 88 holes, observe whether the copper on the surface has been removed. The laser output density was changed from 1.0 MW/cm ² to 6.5 MW/cm ² at intervals of 0.1 MW/cm ² , and the above-mentioned laser processing and observation were performed respectively. Then, the lowest laser output density among the laser output densities in which the copper on the surface of the 88 holes was removed was taken as the machinable energy (MW/cm ² ). The results are shown in Table 1.

Example 5 (Comparison) Directly use the copper foil with carrier obtained in the market. About this copper foil with a carrier, the evaluation of various characteristics was performed similarly to Examples 1-4 and 6-11 (evaluation (8a)-(8e)). The results are shown in Table 1.

[Table 1] Table 1 manufacturing conditions Evaluation carrier Ultra-thin copper foil Ultra-thin copper foil performance Number of polishing wheels Concentration of CBTA in solution (ppm) Thickness (μm) Planar crystal size S ₁ (nm) on the peeled layer side Cross-sectional crystal size S ₂ (nm) S ₂ /S ₁ Planar crystal size S ₃ (nm) on the side opposite to the peeling layer Machinable energy (MW/cm ² ) example 1 #2000 6.6 1.8 107 567 5.3 562 4.6 Example 2 - (precipitation surface) 1.2 1.9 141 393 2.8 544 4.5 Example 3 #1000 0.8 1.8 154 355 2.3 531 4.3 Example 4 #2000 0.1 1.9 359 583 1.6 573 5.0 Example 5* - - 1.9 6271 3624 0.6 6404 6.1 Example 6 #2000 4.0 0.3 118 180 1.5 143 1.3 Example 7 #2000 4.0 0.8 110 230 2.1 193 2.4 Example 8 #1000 5.9 1.0 134 255 1.9 237 3.1 Example 9 #2000 6.5 1.2 124 336 2.7 342 4.1 Example 10 #2000 6.0 1.9 154 530 3.4 519 4.5 Example 11* #2000 0 1.7 2421 1941 0.8 2276 5.2 * indicates a comparative example.

12: ultra-thin copper foil 12a: surface of ultra-thin copper foil 14: roughened particle 14a most concave part 16: resin layer 18: laminate A: line B: line segment G ₁ : copper crystal grain G ₃ : copper crystal grain L: mine Shooting S ₁ : plane size S ₂ : section size S ₃ : plane size

Fig. 1 is a schematic cross-sectional view of a laminate produced using the copper foil with a carrier of the present invention. Fig. 2 is a schematic cross-sectional view illustrating the thickness of the ultra-thin copper foil in the copper foil with a carrier of the present invention.

12: Very thin copper foil

14: coarse particles

16: resin layer

18: laminated body

G ₁ : Copper grain

G ₃ : Copper grain

L: Laser

S ₁ : plane size

S ₂ : section size

S ₃ : plane size

Claims (11)

A copper foil with a carrier, which is sequentially provided with a carrier, a release layer, and an ultra-thin copper foil, the surface of the above-mentioned ultra-thin copper foil on the side of the release layer measured by electron backscatter diffraction (EBSD) The plane size S1 _of the copper crystal grains is not less than 50 nm and not more than 600 nm. The copper foil with a carrier as claimed in claim 1, wherein the cross-sectional size S2 of the copper grains constituting the ultra-thin copper foil measured by electron backscatter diffraction (EBSD) is not less than ₂₀₀ nm and not more than 600 nm. The copper foil with a carrier according to claim 1 or 2, wherein the ratio of the cross-sectional dimension S ₂ to the plane dimension S ₁ , namely S ₂ /S ₁ , is 0.7 to 6.0. The copper foil with a carrier according to claim 1 or 2, wherein the plane of the copper crystal grains present on the surface of the above-mentioned ultra-thin copper foil opposite to the above-mentioned peeling layer is measured by electron backscatter diffraction (EBSD) The size S3 is not less _than 100 nm and not more than 600 nm. The copper foil with a carrier according to claim 1 or 2, wherein the thickness of the above-mentioned ultra-thin copper foil is 2.0 μm or less. The copper foil with a carrier according to claim 1 or 2, wherein the above-mentioned ultra-thin copper foil is further equipped with a group selected from the group consisting of a roughening layer containing a plurality of roughening particles, an anti-rust treatment layer, and a silane coupling agent layer at least one layer. The copper foil with a carrier according to claim 1 or 2, wherein the carrier includes a metal layer. The copper foil with a carrier according to claim 1 or 2, further comprising an auxiliary metal layer between the peeling layer and the carrier and/or the ultra-thin copper foil. A copper foil laminate, which includes: a copper foil with a carrier, which is sequentially provided with a carrier, a release layer, and an ultra-thin copper foil; and a resin layer, which is arranged on the surface of the ultra-thin copper foil with a carrier, by The plane size S1 _of the copper crystal grains present on the surface of the above-mentioned ultra-thin copper foil on the side of the above-mentioned release layer measured by electron backscattering diffraction (EBSD) is 50 nm or more and 600 nm or less. A printed wiring board comprising the copper foil with a carrier according to any one of Claims 1 to 8. A method of manufacturing a printed wiring board, characterized in that the printed wiring board is manufactured using the copper foil with a carrier according to any one of claims 1 to 8.

Images