JP6529640B2 - Ultra-thin copper foil with carrier and method for manufacturing the same - Google Patents

Description

  The present invention relates to a carrier-attached ultrathin copper foil and a method of manufacturing the same.

  In recent years, the MSAP (modified semi-additive process) method has been widely adopted as a method of manufacturing a printed wiring board suitable for circuit miniaturization. The MSAP method is a method suitable for forming an extremely fine circuit, and in order to take advantage of its features, it is carried out using an ultrathin copper foil with a carrier foil. For example, as shown in FIGS. 1 and 2, the ultra-thin copper foil 10 is applied to the insulating resin substrate 11 provided with the prepreg 11b on the base substrate 11a (a lower layer circuit 11c may be embedded if necessary). After pressing and bringing into close contact with each other 12 (step (a)) and peeling off the carrier foil (not shown), the via hole 13 is formed by laser drilling as required (step (b)). Next, chemical copper plating 14 is applied (step (c)), then masking with a predetermined pattern is performed by exposure and development using dry film 15 (step (d)) and electrolytic copper plating 16 is applied (step (e) )). After the dry film 15 is removed to form the wiring portion 16a (step (f)), unnecessary ultrathin copper foil or the like between the adjacent wiring portions 16a and 16a is removed by etching over their entire thickness (step (G) to obtain the wiring 17 formed in a predetermined pattern.

  In particular, in recent years, with the reduction in size and weight of electronic circuits, copper foils for MSAP method that are superior in circuit formability (for example, capable of forming fine circuits of line / space = 15 μm or less / 15 μm or less) are required. For example, in Patent Document 1 (International Publication No. 2012/046804), a peeling layer, a copper foil is formed on a carrier foil having an average spacing Sm of irregularities of the surface of a body specified by JIS-B-0601-1994 of 25 μm or more. Are laminated in this order, and a copper foil formed by peeling the copper foil from the carrier foil is disclosed. By using this copper foil, the linearity of the wiring line is impaired until the line / space is as thin as 15 .mu.m or less. It is believed that etching is possible without

  In recent years, direct laser drilling, in which a via hole is formed by directly irradiating a very thin copper foil with a laser, is frequently used for the via hole processing of a copper clad laminate (see, for example, Patent Document 2 See, for example, JP 346060). In this method, after the surface of the ultrathin copper foil is generally subjected to a blackening treatment, the carbonized gas laser is irradiated to the surface subjected to the blackening treatment to form holes in the ultrathin copper foil and the insulating layer immediately below it. Opening is done.

International Publication No. 2012/046804 JP-A-11-346060

  By the way, since the blackening treatment requires time and cost, and the yield can be lowered, it is advantageous if direct laser drilling can be desirably performed on the surface of the ultrathin copper foil without performing the blackening treatment. However, when direct laser drilling is performed on the surface of the carrier-attached ultrathin copper foil described in Patent Document 1, it is difficult to make a desired hole under ordinary irradiation conditions, and fine circuit formability and laser processability It turned out that it is not compatible.

  The present inventors have now found that, in an ultrathin copper foil with a carrier, the average distance (Peak spacing) between the surface peaks of the surface on the peeling layer side of the ultrathin copper foil is 20 μm or less, and By applying a surface profile having a maximum height difference (Wmax) of not more than 1.0 μm in the surface on the opposite side of the peeling layer, processing of a copper clad laminate or production of a printed wiring board We have found that it is compatible with laser processability.

  Accordingly, an object of the present invention is to provide a carrier-attached ultrathin copper foil capable of achieving both fine circuit formation and laser processability in the processing of a copper-clad laminate or the production of a printed wiring board.

According to one aspect of the present invention, an ultra thin copper foil with carrier comprising a carrier foil, a peeling layer and an ultra thin copper foil in this order,
The surface on the peeling layer side of the ultra-thin copper foil has an average distance (Peak spacing) between surface peaks of 20 μm or less, and the surface on the opposite side of the peeling layer of the ultra-thin copper foil has a maximum height of waviness There is provided a carrier-attached ultrathin copper foil having a difference (Wmax) of 1.0 μm or less.

According to another aspect of the present invention, there is provided a method of producing a carrier-attached ultrathin copper foil according to the above aspect,
Providing a carrier foil having a surface having an average valley spacing (Valley spacing) of 15 μm or less and a maximum undulation difference (Wmax) of 0.8 μm or less;
Forming a release layer on the surface of the carrier foil;
Forming an ultra-thin copper foil on the release layer;
A method is provided comprising.

  According to still another aspect of the present invention, there is provided a copper-clad laminate obtained using the ultra thin copper foil with a carrier according to the above aspect.

  According to still another aspect of the present invention, there is provided a printed wiring board obtained using the ultra thin copper foil with carrier according to the above aspect.

It is a process flowchart for demonstrating MSAP method, and is a figure which shows the first half process (process (a)-(d)). It is a process flowchart for demonstrating MSAP method, and is a figure which shows the latter process (process (e)-(g)). It is a figure which illustrates notionally the method of counting the cut surface number of roughening particle | grains in the cut surface of predetermined height from a basal plane. It is a figure which shows an example of the distribution curve of the cut number of roughening particle | grains in the cut surface according to the height from a basal plane obtained in Example 7. FIG.

Definitions The definitions of the parameters used to identify the invention are given below.

  In the present specification, “average distance between surface peaks (Peak spacing)” refers to a peak after removing the high frequency wave component from the information on the unevenness of the sample surface obtained using a three-dimensional surface structure analysis microscope. It refers to the average distance between peaks in data extracted by filtering waveform data.

  In the present specification, “Valley spacing” refers to the waveform data of the valley after removing the high frequency wave component from the information on the unevenness of the sample surface obtained using a three-dimensional surface structure analysis microscope. The mean distance between valleys in the data extracted by filtering.

  In the present specification, “maximum difference in height (Wmax) of waviness” refers to when waveform data relating to waviness is extracted using a filter from information relating to the unevenness of the sample surface obtained using a three-dimensional surface structure analysis microscope. Of the height difference of the waveform data (the sum of the maximum peak height and the maximum valley depth of the waveform).

  The average distance between surface peaks (Peak spacing), the average distance between valleys (Valley spacing), and the maximum height difference (Wmax) of undulations are all commercially available three-dimensional surface structure analysis microscopes (eg, zygo New View 5032 ( It can measure by setting a low frequency filter to 11 μm condition using Zygo's product) and commercially available analysis software (for example, Metro Pro Ver. 8. 0.2). At this time, the surface to be measured of the foil is fixed in contact with the sample table and fixed, and the field of view of 108 μm × 144 μm is selected and measured within 6 cm square of the sample piece and obtained from 6 measurement points. It is preferable to adopt the average value of the measured values as a representative value.

  In the present specification, the "electrode surface" of the carrier foil refers to the surface of the carrier foil that was in contact with the rotating cathode at the time of production of the carrier foil.

  In the present specification, the "deposition surface" of the carrier foil refers to the surface on which electrolytic copper is deposited at the time of production of the carrier foil, that is, the surface not in contact with the rotating cathode.

Carrier-attached ultrathin copper foil and method of producing the same The carrier-attached ultrathin copper foil of the present invention comprises a carrier foil, a release layer and an ultrathin copper foil in this order. And, the surface on the peeling layer side of the ultra thin copper foil has an average distance (Peak spacing) of 20 μm or less between the surface peaks, and the surface on the opposite side of the peeling layer of the ultra thin copper foil has the maximum height of waviness The difference (Wmax) is 1.0 μm or less. This makes it possible to achieve both fine circuit formability and laser processability in the processing of a copper-clad laminate or in the manufacture of a printed wiring board. In addition, the blackening treatment generally adopted so far for securing the laser processability can be made unnecessary in the present invention.

  Although fine circuit formation and laser processability are inherently incompatible, according to the present invention, they become unexpectedly compatible. In order to obtain excellent fine circuit formation, an ultrathin copper foil having a smooth surface on the side opposite to the release layer is originally required. And in order to obtain such an ultrathin copper foil, although the ultrathin copper foil in which the surface by the side of the exfoliation layer is smooth is called for, a laser becomes easy to be reflected, so that the surface is smoothed. It is because it becomes difficult to be absorbed by thin copper foil and laser processability falls. In fact, as described above, when direct laser drilling is performed on the surface of the carrier-attached ultrathin copper foil described in Patent Document 1, it is difficult to make a desired hole under ordinary irradiation conditions, and microcircuit formation and laser It turned out that it is not compatible with processability. As a result of investigations by the inventors of the present invention, it was found that the main factor for reducing the fine circuit formability was the waviness of the surface of the ultrathin copper foil opposite to the release layer. Then, it was found that controlling the maximum height difference (Wmax) of the waviness to 1.0 μm or less is effective in improving the fine circuit formability. In addition, it was also found out that the factor that reduces the direct laser drilling processability is the case where the average distance (Peak spacing) between surface peaks of the surface on the peeling layer side of the ultrathin copper foil exceeds 20 μm. As described above, according to the ultra thin copper foil with carrier of the present invention, by controlling Wmax and Peak spacing in an ultra thin copper foil (particularly, ultra thin copper foil for MSAP), line / space = 15 μm / 15 μm or less It is possible to desirably perform direct laser drilling while achieving an excellent fine circuit formability that can form a circuit.

  Thus, the ultra-thin copper foil has a surface with an average distance between peak peaks (Peak spacing) of 20 μm or less on the surface on the release layer side, and the maximum height difference (Wmax) of the waviness is 1.0 μm. The following surface is provided on the side opposite to the release layer. By setting the two parameters within the above range, it is possible to achieve both the fine circuit formability and the laser processability in the processing of a copper-clad laminate or in the manufacture of a printed wiring board. The average distance (Peak spacing) between surface peaks in the surface on the peeling layer side of the ultrathin copper foil is 20 μm or less, preferably 1 to 15 μm, more preferably 5 to 15 μm, and still more preferably 10 to 15 μm. Moreover, the maximum height difference (Wmax) of the undulation in the surface on the opposite side to the peeling layer of the ultrathin copper foil is 1.0 μm or less, preferably 0.9 μm or less, more preferably 0.8 μm or less. In particular, in order to form a fine circuit of line / space = 15/15 μm, it is preferable that Wmax of the ultrathin copper foil surface is 0.8 μm or less. The lower limit of Wmax is better as it is lower, so the lower limit is not particularly limited, but Wmax is typically 0.1 μm or more, and more typically 0.2 μm or more.

  The surface on the release layer side of the ultrathin copper foil also preferably has a maximum height difference (Wmax) of waviness of 1.0 μm or less, more preferably 0.8 μm, and still more preferably 0.6 μm or less. Thus, Wmax of the surface on the opposite side to the peeling layer of ultra-thin copper foil can be restrained low as it is low Wmax, and it is excellent in fine circuit formation property. In particular, in order to form a fine circuit of line / space = 15/15 μm, Wmax is preferably 0.6 μm or less. The lower limit of Wmax is not particularly limited because it is better if Wmax is lower. In particular, in the case where the thickness of the ultrathin copper foil is reduced (for example, when the thickness is set to 2.0 μm or less), Wmax is preferably smaller. However, Wmax is typically 0.1 μm or more, and more typically 0.2 μm or more.

  It is preferable that the surface on the opposite side to the peeling layer of the ultrathin copper foil is a roughened surface. That is, it is preferable that one surface of the ultrathin copper foil is roughened. By doing this, the adhesion to the resin layer at the time of producing a copper-clad laminate or a printed wiring board can be improved. This roughening treatment can be carried out by forming roughened particles with copper or a copper alloy on an extremely thin copper foil. For example, a known plating method through at least two types of plating processes including a burn plating process in which fine copper particles are deposited on very thin copper foil and an overlay plating process for preventing the fine copper particles from falling off Preferably, it is carried out according to

  Typically, the roughened surface comprises a plurality of roughened particles. Preferably, the plurality of roughening particles have an average roughening particle height from the basal plane of 1.0 to 1.4 μm, and the roughening particles in the cut surface according to the height from the basal plane. The 1/10 value width of the distribution curve of the number of cuts is 1.3 μm or less. These parameters can be obtained by measuring the surface profile of the roughened surface at a desired magnification (for example, 600 to 30,000 times) according to the size of the roughened particles using a three-dimensional roughness analyzer. . Here, as illustrated in FIG. 3, the “base surface” is a surface parallel to the ultrathin copper foil, which corresponds to the lowest position in the valley bottom between the plurality of roughened particles. “The cut number of roughened particles in the cut surface according to the height from the basal plane” means the cross-sectional contour curve of the roughened particles and the parallel at a predetermined height from the basal plane, as illustrated in FIG. Number of surface areas to be cut by the cutting surface. That is, from the base surface to the maximum roughened particle height, cutting surfaces are sequentially set while dividing at regular intervals (for example, 0.02 μm) in the height direction, and the number of cut surface of roughened particles in each cutting surface Count. The “roughened particle height” means the height of the roughened particles from the basal plane, and the “average roughened particle height” means the height from the basal plane as exemplified in FIG. In the distribution curve of the number of roughened particles cut at the corresponding cut surface, it means the height from the basal plane (roughened particle height) at which the number of roughened particles becomes largest. In addition, “1/10 value width” means, as illustrated in FIG. 4, the distribution curve of the number of roughened particles in the cut surface according to the height from the basal plane, in the distribution curve of the number of roughened particles It means the distribution width (roughened particle height distribution width) at a value of one tenth of the maximum value. When the average roughened particle height and the 1/10 value width fall within the above range, the height of the roughened particle is reduced, so that the flash etching property in the vertical direction is improved and the variation of the roughened particle is reduced. The etching variation in the surface direction can be reduced, and undesired tailing at the time of circuit formation can be effectively prevented. As a result, circuit formability is improved. Furthermore, when the roughened surface is attached to a resin layer such as a prepreg, the variance due to the position of the peel strength with the resin layer is reduced because the variance of the roughened particles is reduced when the thickness is within the above range. The average roughened particle height is 1.0 to 1.4 μm, preferably 1.0 to 1.3 μm. The 1/10 value width is 1.3 μm or less, preferably 1.0 μm or less. The smaller the 1/10 value width, the better, but typically it is 0.1 μm or more.

  The ultra-thin copper foil is not particularly limited and may be a known configuration adopted for the ultra thin copper foil with carrier except having the above-mentioned specific surface profile. For example, the ultrathin copper foil may be formed by a wet film forming method such as an electroless copper plating method and an electrolytic copper plating method, a dry film forming method such as sputtering and chemical vapor deposition, or a combination thereof. The preferable thickness of the ultrathin copper foil is 0.1 to 5.0 μm, more preferably 0.5 to 3.0 μm, and still more preferably 1.0 to 2.0 μm. For example, in order to form a fine circuit of line / space = 15/15 μm, the thickness of the ultrathin copper foil is particularly preferably 2.0 μm or less.

  The release layer weakens the peel strength of the carrier foil, ensures the stability of the strength, and further has a function to suppress the interdiffusion which may occur between the carrier foil and the copper foil during press molding at high temperature. It is. The release layer is generally formed on one side of the carrier foil, but may be formed on both sides. The release layer may be either an organic release layer or an inorganic release layer. As an example of the organic component used for an organic peeling layer, a nitrogen containing organic compound, a sulfur containing organic compound, carboxylic acid etc. are mentioned. Examples of the nitrogen-containing organic compound include triazole compounds and imidazole compounds. Among these, triazole compounds are preferable in that the releasability is easily stabilized. 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. are mentioned. Examples of sulfur-containing organic compounds include mercaptobenzothiazole, thiocyanuric acid, 2-benzimidazolethiol and the like. Examples of carboxylic acids include monocarboxylic acids, dicarboxylic acids and the like. On the other hand, examples of the inorganic component used for the inorganic release layer include Ni, Mo, Co, Cr, Fe, Ti, W, P, Zn, a chromate-treated film, and the like. The release layer may be formed by bringing a release layer component-containing solution into contact with at least one surface of the carrier foil and fixing the release layer component to the surface of the carrier foil. When the carrier foil is brought into contact with the peeling layer component-containing solution, the contact may be performed by immersion in the peeling layer component-containing solution, spraying of the peeling layer component-containing solution, or flowing of the peeling layer component-containing solution. In addition, the method of film-forming the peeling layer component by the vapor phase method by vapor deposition, sputtering, etc. is also employable. The fixation of the peeling layer component to the carrier foil surface may be carried out by adsorption or drying of the peeling layer component-containing solution, electrodeposition of the peeling layer component in the peeling layer component-containing solution, or the like. The thickness of the release layer is typically 1 nm to 1 μm, preferably 5 nm to 500 nm.

  Carrier foil is a foil for supporting ultra-thin copper foil and improving its handling property. Examples of the carrier foil include an aluminum foil, a copper foil, a stainless steel (SUS) foil, a resin film with a metal coating on the surface, and the like, and a copper foil is preferable. The copper foil may be either a rolled copper foil or an electrolytic copper foil. The thickness of the carrier foil is typically 250 μm or less, preferably 12 μm to 200 μm.

  The surface on the release layer side of the carrier foil preferably has an average valley spacing (Valley spacing) of 15 μm or less, and a maximum difference in undulation (Wmax) of 0.8 μm or less. In the manufacturing process of ultra thin copper foil with carrier, ultra thin copper foil is formed on the surface on the release layer side of the carrier foil, so low valley spacing and Wmax are imparted to the surface of the carrier foil as described above. The desirable surface profile mentioned above can be given to the field by the side of the exfoliation layer of ultra-thin copper foil, and the field opposite to the exfoliation layer by carrying out. That is, the carrier-attached ultrathin copper foil of the present invention has a carrier foil having a surface having an average valley spacing (Valley spacing) of 15 μm or less and a maximum undulation (Wmax) of 0.8 μm or less. It can be manufactured by preparing a release layer on the surface of the carrier foil and forming an ultrathin copper foil on the release layer. The average distance (Valley spacing) of valleys in the surface on the release layer side of the carrier foil is preferably 15 μm or less, more preferably 1 to 10 μm or less, and still more preferably 3 to 8 μm or less. The maximum height difference (Wmax) of the waviness on the surface of the carrier foil on the release layer side is preferably 0.8 μm or less, more preferably 0.7 μm or less, and still more preferably 0.6 μm or less. The lower limit of Wmax is better as it is lower, so the lower limit is not particularly limited, but Wmax is typically 0.1 μm or more, and more typically 0.2 μm or more. The realization of low Valley spacing and Wmax within the above range on the surface of the carrier foil is achieved by polishing the surface of the rotating cathode used in electrolytic foiling of the carrier foil with a predetermined count of buff to adjust the surface roughness. It can be carried out. That is, the surface profile of the thus-prepared rotating cathode is transferred to the electrode surface of the carrier foil, and thus an extremely thin copper foil is formed via the release layer on the electrode surface of the carrier foil to which the desired surface profile is applied. The surface profile described above can be applied to the surface on the peeling layer side of the ultrathin copper foil. Preferred buff counts are greater than # 1000 and less than # 3000, and more preferably # 1500 to # 2500.

  If desired, another functional layer may be provided between the release layer and the carrier foil and / or the ultrathin copper foil. Examples of such other functional layers include auxiliary metal layers. The auxiliary metal layer preferably comprises nickel and / or cobalt. By forming such an auxiliary metal layer on the surface side of the carrier foil and / or on the surface side of the ultrathin copper foil, it can occur between the carrier foil and the ultrathin copper foil during hot press forming at high temperatures or for a long time It is possible to suppress interdiffusion and to ensure the stability of the peel strength of the carrier foil. The thickness of the auxiliary metal layer is preferably 0.001 to 3 μm.

  If desired, the ultrathin copper foil may be subjected to an anticorrosion treatment. The antirust treatment preferably includes a plating treatment using zinc. The plating treatment using zinc may be either zinc plating treatment or 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 containing at least Ni and Zn, and may further contain other elements such as Sn, Cr, Co and the like. The weight ratio of Ni / Zn in the zinc-nickel alloy plating is preferably 1.2 to 10, more preferably 2 to 7, and still more preferably 2.7 to 4. Further, the anticorrosion treatment preferably further includes a chromate treatment, and the chromate treatment is more preferably performed on a surface of a plating containing zinc after a plating treatment using zinc. This can further improve the corrosion resistance. A particularly preferred corrosion protection treatment is the combination of zinc-nickel alloy plating treatment and subsequent chromate treatment.

  If desired, the surface of the ultrathin copper foil may be treated with a silane coupling agent to form a silane coupling agent layer. Thereby, the moisture resistance, the chemical resistance, the adhesion to the adhesive and the like can be improved. The silane coupling agent layer can be formed by appropriately diluting the silane coupling agent, applying it, and drying it. Examples of silane coupling agents include epoxy-functional silane coupling agents such as 4-glycidylbutyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, or γ-aminopropyltrimethoxysilane, N-β (amino Amino functions such as ethyl) γ-aminopropyltrimethoxysilane, N-3- (4- (3-aminopropoxy) butoxy) propyl-3-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. -Functional silane coupling agent, or mercapto functional silane coupling agent such as γ-mercaptopropyltrimethoxysilane or vinyltrimethoxysilane, olefin functional silane coupling agent such as vinylphenyltrimethoxysilane, or γ-methacryloxypropyl Trimetoki Acrylic-functional silane coupling agent such as a silane, or imidazole functional silane coupling agent such as imidazole silane, or triazine functional silane coupling agents such as triazine silane.

Ultrathin copper foil with a carrier of the copper-clad laminates present invention is preferably used for manufacturing the copper - clad laminates for printed wiring boards. That is, according to a preferred embodiment of the present invention, there is provided a copper-clad laminate obtained using a carrier-attached ultrathin copper foil. By using the carrier-attached ultrathin copper foil of the present invention, it is possible to achieve both the fine circuit formability and the laser processability in the processing of a copper clad laminate. This copper-clad laminate comprises the carrier-attached ultrathin copper foil of the present invention and a resin layer provided in close contact with the surface treatment layer. The carrier-attached ultrathin copper foil may be provided on one side or both sides of the resin layer. The resin layer comprises a resin, preferably an insulating resin. The resin layer is preferably a prepreg and / or a resin sheet. A prepreg is a general term for a composite material in which a synthetic resin is impregnated in a base material such as a synthetic resin plate, a glass plate, a glass woven fabric, a glass non-woven fabric, and paper. Preferred examples of the insulating resin include epoxy resin, cyanate resin, bismaleimide triazine resin (BT resin), polyphenylene ether resin, phenol resin and the like. Moreover, as an example of the insulating resin which comprises a resin sheet, insulating resin, such as an epoxy resin, a polyimide resin, a polyester resin, is mentioned. The resin layer may contain filler particles and the like composed of various inorganic particles such as silica and alumina from the viewpoint of improving the insulation and the like. The thickness of the resin layer is not particularly limited, but is preferably 1 to 1000 μm, more preferably 2 to 400 μm, and still more preferably 3 to 200 μm. The resin layer may be composed of a plurality of layers. A resin layer such as a prepreg and / or a resin sheet may be provided on the carrier-attached ultrathin copper foil via a primer resin layer previously applied to the copper foil surface.

Printed Wiring Board The carrier-attached ultrathin copper foil of the present invention is preferably used for producing a printed wiring board. That is, according to a preferred embodiment of the present invention, there is provided a printed wiring board obtained using a carrier-attached ultrathin copper foil. By using the carrier-attached ultrathin copper foil of the present invention, it is possible to achieve both fine circuit formability and laser processability in the production of a printed wiring board. The printed wiring board according to this aspect includes a layer configuration in which a resin layer and a copper layer are laminated in this order. The copper layer is a layer derived from the ultra-thin copper foil of the ultra-thin copper foil with carrier of the present invention. The resin layer is as described above for the copper clad laminate. Anyway, as the printed wiring board, a known layer configuration can be adopted except that the carrier-attached ultrathin copper foil of the present invention is used. Specific examples of the printed wiring board include a single-sided or double-sided printed wiring board on which a circuit is formed by bonding the ultra-thin copper foil of the present invention to one side or both sides of the prepreg and curing it. A printed wiring board etc. are mentioned. Moreover, as another specific example, the flexible printed wiring board which forms the ultra-thin copper foil of this invention on a resin film, and forms a circuit, COF, a TAB tape etc. are mentioned. As still another specific example, after forming the resin-coated copper foil (RCC) coated with the above-mentioned resin layer on the ultra-thin copper foil of the present invention and laminating the resin layer as the insulating adhesive layer on the above-mentioned printed circuit board , A buildup wiring board in which a circuit is formed by a method such as modified semiadditive (MSAP) method or subtractive method by using ultrathin copper foil as all or part of the wiring layer, or semiadditive by removing ultrathin copper foil And a direct build-up-on-wafer that alternately repeats lamination of resin-coated copper foil and circuit formation on a semiconductor integrated circuit. As a more developed example, an antenna element formed by laminating the above-mentioned resin-coated copper foil on a substrate and forming a circuit, an electronic material for a panel or display formed by laminating on a glass or a resin film through an adhesive layer and a window Also included are electronic materials for glass, electromagnetic wave shielding films in which a conductive adhesive is applied to the ultrathin copper foil of the present invention, and the like. In particular, the carrier-attached ultrathin copper foil of the present invention is suitable for the MSAP method. For example, when the circuit is formed by the MSAP method, the configurations as shown in FIGS. 1 and 2 can be employed.

  The invention is further illustrated by the following examples.

Examples 1 to 5
After forming a peeling layer and an ultrathin copper foil layer in order on the electrode surface side of the carrier foil, an anticorrosive treatment and a silane coupling agent treatment were performed to produce an ultrathin copper foil with carrier. Then, various evaluations were performed on the obtained ultrathin copper foil with carrier. The specific procedure is as follows.

(1) Preparation of Carrier Foil Using a copper electrolyte having the composition shown below, a rotating cathode, and DSA (dimensionally stable anode) as an anode, electrolysis at a solution temperature of 50 ° C. and a current density of 70 A / dm ² Then, an 18 μm thick electrolytic copper foil was produced as a carrier foil. At this time, the surface is polished with a buff of # 2500 (Example 1), # 2000 (Example 2), # 1500 (Example 3), # 1000 (Example 4) or # 3000 (Example 5) as a rotating cathode. The electrode whose 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
-Glue concentration: 5 mg / L

(2) Formation of exfoliation layer The electrode surface of the pickled carrier foil was treated with an aqueous CBTA solution having a CBTA (carboxybenzotriazole) concentration of 1 g / L, a sulfuric acid concentration of 150 g / L and a copper concentration of 10 g / L at a liquid temperature of 30 ° C. The CBTA component was adsorbed onto the electrode surface of the carrier foil. Thus, the CBTA layer was formed as an organic release layer on the electrode surface of the carrier foil.

(3) Formation of Auxiliary Metal Layer The carrier foil on which the organic release layer is formed is immersed in a solution containing nickel concentration 20 g / L prepared using nickel sulfate, and the solution temperature is 45 ° C., pH 3, current density 5 A A deposition amount of nickel equivalent to 0.001 μm was deposited on the organic release layer under the condition of dm ² . Thus, a nickel layer was formed as an auxiliary metal layer on the organic release layer.

(4) Formation of ultrathin copper foil The carrier foil on which the auxiliary metal layer is formed is immersed in a copper solution of the composition shown below to electrolyze at a solution temperature of 50 ° C. and a current density of 5 to 30 A / dm ² , An ultra-thin copper foil 2 μm thick was formed on the auxiliary metal layer.
<Composition of solution>
-Copper concentration: 60 g / L
-Sulfuric acid concentration: 200 g / L

(5) Roughening treatment The surface of the ultrathin copper foil thus formed was roughened. This roughening treatment is composed of a burn plating process in which fine copper particles are deposited and deposited on an extremely thin copper foil, and an overlay plating process for preventing the fine copper particles from falling off. In the burnt plating step, roughening treatment was performed at a liquid temperature of 25 ° C. and a current density of 15 A / dm ² using an acidic copper sulfate solution containing 10 g / L of copper concentration and 120 g / L of sulfuric acid concentration. In the subsequent plating step, electrodeposition was carried out using a solution of acidic copper sulfate containing 70 g / L of copper and 120 g / L of sulfuric acid under smooth plating conditions at a liquid temperature of 40 ° C. and a current density of 15 A / dm ² .

(6) Anticorrosion treatment The surface of the roughened layer of the obtained carrier-attached ultrathin copper foil was subjected to an anticorrosion treatment consisting of zinc-nickel alloy plating treatment and chromate treatment. First, a roughened layer is formed using an electrolyte having a zinc concentration of 0.2 g / L, a nickel concentration of 2 g / L, and a potassium pyrophosphate concentration of 300 g / L under the conditions of a liquid temperature of 40 ° C. and a current density of 0.5 A / dm ² And the zinc-nickel alloy plating process was performed to the surface of a carrier foil. Next, the surface treated with zinc-nickel alloy plating was subjected to chromate treatment using a 3 g / L aqueous solution of chromic acid under the conditions of pH 10 and current density 5 A / dm ² .

(7) Silane coupling agent treatment An aqueous solution containing 2 g / L of γ-glycidoxypropyltrimethoxysilane is adsorbed onto the surface of the ultrathin copper foil on the very thin copper foil with carrier, and water is evaporated by an electric heater. , And treated with a silane coupling agent. At this time, the silane coupling agent treatment was not performed on the carrier foil side.

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

<Surface texture parameter>
Using zygo New View 5032 (manufactured by Zygo) as a measurement device, Metro Pro Ver. The maximum height difference (Wmax), the average distance between surface peaks (Peak spacing), and the maximum height difference (Wmax) of carrier foils and ultra thin copper foils using a low frequency filter of 11 μm, using 8.0.2, The average distance between valleys (Valley spacing) was measured. At this time, ultra-thin copper foil or carrier foil is brought into close contact with the sample base and fixed, and a field of view of 108 μm × 144 μm is selected and measured within 6 cm square area of the sample piece, and 6 measurement points The average value of the measured values obtained from was adopted as a representative value. In addition, about the surface by the side of the peeling layer of ultra-thin copper foil, it measured after producing the copper clad laminated board for laser processability evaluation mentioned later.

For Example 2, a surface profile of a 10800 μm ² area (120 μm × 90 μm) on the surface (roughened surface side) of an ultrathin copper foil was measured using a three-dimensional roughness analyzer (ERA-8900, manufactured by Elionix Co., Ltd.) The average roughened particle height and the 1/10 value width were determined by analyzing under the conditions of measurement magnification: 1000 times, acceleration voltage: 10 kV, Z-axis interval: 0.02 μm. In this surface analysis, the cut surface is divided at constant intervals (0.02 μm) in the height direction from the lowest position (corresponding to the basal surface) of the valley bottoms between the roughened particles to the maximum roughened particle height. It set by one by one and was performed by counting the number of cut edges of roughening particle | grains in each cut surface. It goes without saying that the larger the number of facets, the larger the number of roughened particles, and vice versa. Then, the vertical axis represents the number of cuts in the cut surface, and the horizontal axis represents the height from the base surface. Based on this distribution curve and the definition described above, the average roughened particle height and 1/10 value width were determined.

<Laser processability>
The copper clad laminated board was produced using the carrier-attached ultrathin copper foil, and the laser processability was evaluated. First, an ultrathin copper foil of a carrier-attached ultrathin copper foil is laminated on the surface of the inner layer substrate via a prepreg (Mitsubishi Gas Chemical Co., Ltd., 830NX-A, thickness 0.1 mm) under a pressure of 0.4 MPa. After thermocompression bonding at a temperature of 220 ° C. for 90 minutes, the carrier foil was peeled off to produce a copper-clad laminate. Thereafter, using a carbon dioxide gas laser, a pulse width of 14 μsec. The laser processing was performed on the copper clad laminate under the conditions of pulse energy of 6.4 mJ and laser beam diameter of 108 μm. At that time, a hole diameter after processing of 60 μm or more was determined to be A, and less than 60 μm was determined to be B.

<Circuit formability>
The evaluation of the circuit formability was performed as follows. First, a dry film was attached to the surface of the above-mentioned copper-clad laminate, exposure and development were performed to form a plating resist. Then, electrolytic copper plating was formed to a thickness of 18 μm on the surface of the copper-clad laminate on which the plating resist was not formed. Next, the plating resist is peeled off and treated with an etching solution (CPE 800, manufactured by Mitsubishi Gas Chemical Co., Ltd.) using hydrogen peroxide and sulfuric acid to dissolve and remove the ultrathin copper foil remaining between the circuits. , And a line / space = 15 μm / 15 μm wiring pattern was formed. At this time, those having a wiring pattern width of ± 2 μm or less were determined as S, those having a width of more than ± 2 μm and 5 μm or less as A, and the other as B.

Example 6 (comparison)
After forming a peeling layer and an ultrathin copper foil layer in order on the deposition side of the carrier foil, a rustproofing treatment and a silane coupling agent treatment were performed to produce an ultrathin copper foil with carrier. Then, various evaluations were performed on the obtained ultrathin copper foil with carrier. The specific procedure is as follows.

(1) Preparation of Carrier Foil Using a copper electrolyte of the composition shown below, a rotating cathode, and DSA (dimensionally stable anode) as an anode, electrolysis is carried out at a solution temperature of 50 ° C. and a current density of 60 A / dm ² An electrolytic copper foil having a thickness of 18 μm was produced as a carrier foil. At this time, an electrode whose surface roughness was adjusted by polishing the surface with a buff of # 1000 was used as a rotating cathode.
<Composition of Copper Electrolyte>
-Copper concentration: 80 g / L
-Sulfuric acid concentration: 280 g / L
-Diallyldimethyl ammonium chloride concentration: 30 mg / L
-Bis (3-sulfopropyl) disulfide concentration: 5 mg / L

(2) Formation of exfoliation layer The pickled carrier foil is immersed in an aqueous CBTA solution of 1 g / L of CBTA (Carboxybenzotriazole), 150 g / L of sulfuric acid and 10 g / L of copper at a liquid temperature of 30 ° C. for 30 seconds. The CBTA component was adsorbed to the deposition surface of the carrier foil. Thus, the CBTA layer was formed as an organic release layer on the deposition surface of the carrier foil.

(3) Subsequent Steps and Evaluation According to the same procedure as described in (3) to (8) of Examples 1 to 5, the auxiliary metal layer was formed on the organic release layer formed on the deposition surface side of the carrier foil. Formation, formation of ultrathin copper foil, roughening treatment, rust prevention treatment, silane coupling treatment, and various evaluations were performed.

Example 7
The burnt plating step in the roughening treatment was carried out using an acidic copper sulfate solution containing 10 g / L of copper concentration, 120 g / L of sulfuric acid concentration and 2 mg / L of carboxybenzotriazole at a liquid temperature of 25 ° C. and a current density of 15 A / dm ² In the same manner as in Example 2 except that the tempering treatment was performed, preparation and evaluation of a carrier-attached ultrathin copper foil were performed. The distribution curve of the number of cut surface of roughened particles in the cut surface according to the height from the basal plane was as shown in FIG.

The evaluation results obtained in Result Examples 1 to 7 are as shown in Table 1.

The present invention includes the following aspects.
[Item 1]
An ultra thin copper foil with carrier comprising a carrier foil, a peeling layer and an ultra thin copper foil in this order,
The surface on the peeling layer side of the ultra-thin copper foil has an average distance (Peak spacing) between surface peaks of 20 μm or less, and the surface on the opposite side of the peeling layer of the ultra-thin copper foil has a maximum height of waviness Carrier-attached ultra-thin copper foil with a difference (Wmax) of 1.0 μm or less.
[Section 2]
The carrier-attached ultrathin copper foil according to Item 1, wherein the surface on the peeling layer side of the ultrathin copper foil has an average distance (Peak spacing) between the surface peaks of 1 to 15 μm.
[Section 3]
The extremely thin copper foil with a carrier according to claim 1 or 2, wherein the surface on the opposite side of the peeling layer of the ultra thin copper foil has a maximum height difference (Wmax) of not more than 0.8 μm in undulation.
[Section 4]
The carrier-attached ultrathin copper foil according to any one of Items 1 to 3, wherein the surface of the ultrathin copper foil opposite to the release layer is a roughened surface.
[Section 5]
The roughening surface has a plurality of roughening particles, and the plurality of roughening particles have an average roughening particle height from the basal plane of 1.0 to 1.4 μm, and from the basal plane The 1/10 value width of the distribution curve of the number of cut edges of roughened particles in the cut surface according to the height is 1.3 μm or less, and the base surface corresponds to the lowest position among the valley bottoms among the plurality of roughened particles 5. The ultra thin copper foil with a carrier according to item 4, which is a plane parallel to the ultra thin copper foil.
[Section 6]
The carrier-attached ultrathin copper foil according to any one of Items 1 to 5, wherein the surface on the release layer side of the ultrathin copper foil has a maximum height difference (Wmax) of waviness of 1.0 μm or less.
[Section 7]
The carrier-attached ultrathin copper foil according to any one of Items 1 to 6, wherein the ultrathin copper foil has a thickness of 0.1 to 5.0 μm.
[Section 8]
The surface on the peeling layer side of the carrier foil is any one of items 1 to 7, wherein the average distance between valleys (Valley spacing) is 15 μm or less, and the maximum height difference (Wmax) of undulations is 0.8 μm or less. Ultrathin copper foil with carrier according to one of the claims.
[Section 9]
Item 9. A method for producing a carrier-attached ultrathin copper foil according to any one of items 1 to 8,
Providing a carrier foil having a surface having an average valley spacing (Valley spacing) of 15 μm or less and a maximum undulation difference (Wmax) of 0.8 μm or less;
Forming a release layer on the surface of the carrier foil;
Forming an ultra-thin copper foil on the release layer;
A method comprising.
[Section 10]
10. The method according to item 9, wherein a surface of the carrier foil has an average valley spacing (valley spacing) of 1 to 10 μm.
[Item 11]
11. The method according to item 9 or 10, wherein the surface of the carrier foil has a maximum difference in height (Wmax) of undulation of 0.1 to 0.7 μm.
[Section 12]
Item 9. A copper-clad laminate obtained using the carrier-attached ultrathin copper foil according to any one of Items 1 to 8.
[Section 13]
Item 9. A printed wiring board obtained using the carrier-attached ultrathin copper foil according to any one of items 1 to 8.

Claims (11)

An ultra thin copper foil with carrier comprising a carrier foil, a peeling layer and an ultra thin copper foil in this order,
The surface on the peeling layer side of the ultrathin copper foil has an average distance (Peak spacing) between surface peaks of not more than 20 μm, and a maximum height difference (Wmax) of waviness of not more than 1.0 μm, and the ultrathin copper foil The peeling layer and the surface on the opposite side are carrier-attached ultrathin copper foils having a maximum height difference (Wmax) of not more than 1.0 μm.   The carrier-attached ultrathin copper foil according to claim 1, wherein the surface on the peeling layer side of the ultrathin copper foil has an average distance (Peak spacing) between the surface peaks of 1 to 15 m.   The ultrathin copper foil with a carrier according to claim 1 or 2, wherein the surface on the opposite side of the peeling layer of the ultrathin copper foil has a maximum height difference (Wmax) of not more than 0.8 μm.   The ultrathin copper foil with a carrier according to any one of claims 1 to 3, wherein the surface opposite to the peeling layer of the ultrathin copper foil is a roughened surface. The roughening surface has a plurality of roughening particles, and the plurality of roughening particles have an average roughening particle height from the basal plane of 1.0 to 1.4 μm, and from the basal plane The 1/10 value width of the distribution curve of the number of cut edges of roughened particles in the cut surface according to the height is 1.3 μm or less, and the base surface corresponds to the lowest position among the valley bottoms among the plurality of roughened particles Parallel to the extra-thin copper foil
And the number of cut faces of roughened particles in the cut surface according to the height from the basal plane is the same as that of the roughened particles.
Cross-sectional contour curve and plane to be cut by parallel cutting planes at a given height from the base plane
The number of regions, and the height of the roughening particles is the height of the roughening particles from the basal plane, the average roughening
According to the distribution curve of the number of cut surface of roughened particles in the cutting plane according to the height of the particle from the basal plane
And the height from the basal plane where the number of cut roughened particles is maximized, and the 1/10 value width is
Roughening in the distribution curve of the number of cut edges of roughened particles in the cut surface according to the height from the basal plane
5. The ultrathin copper foil with carrier according to claim 4, wherein the distribution width is a value at 1/10 of the maximum value of the number of cut faces of particles.   The carrier-attached ultrathin copper foil according to any one of claims 1 to 5, wherein the ultrathin copper foil has a thickness of 0.1 to 5.0 μm. It is a manufacturing method of the carrier with ultra-thin copper foil as described in any one of Claims 1-6, Comprising:
Providing a carrier foil having a surface having an average valley spacing (Valley spacing) of 15 μm or less and a maximum undulation difference (Wmax) of 0.8 μm or less;
Forming a release layer on the surface of the carrier foil;
Forming an ultra-thin copper foil on the release layer;
A method comprising.   The method according to claim 7, wherein the surface of the carrier foil has an average valley spacing distance of 1 to 10 μm.   The method according to claim 7 or 8, wherein the surface of the carrier foil has a maximum height difference (Wmax) of undulation of 0.1 to 0.7 μm.   The copper clad laminated board provided with the carrier with ultra-thin copper foil as described in any one of Claims 1-6. A method for producing a printed wiring board, comprising producing a printed wiring board using the carrier-attached ultrathin copper foil according to any one of claims 1 to 6.

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