Carrier foil-attached foil equipped with ultra-thin copper foil and manufacturing method therefor

Abstract

The present invention relates to a carrier foil-attached foil equipped with an ultra-thin copper foil having a low-roughness smooth surface, and a manufacturing method therefor. The present invention provides a carrier foil-attached foil in which a carrier foil, a release layer, and an ultra-thin copper foil are sequentially laminated, wherein the carrier foil includes an electrolytic polishing surface facing the release layer.

Description

Carrier foil attachment foil having ultra-thin copper foil and method for manufacturing the same

[0001] The present invention relates to a carrier foil attachment foil, and more particularly, to a carrier foil attachment foil having an ultra-thin copper foil having a smooth surface with low roughness, and a method for manufacturing the same.

[0002] Conventional carrier foil attachment foils for semiconductor substrates typically have a laminated structure in which a peeling layer, a heat-resistant layer, and an ultra-thin copper foil are sequentially formed on the carrier foil, and the surface shape of the ultra-thin copper foil is determined according to the surface shape of the carrier foil.

[0003] In the case of copper foil manufactured through electroplating, which is a roll-to-roll continuous process, a drum polishing texture exists, and the shape of the ultra-thin copper foil can also be determined according to the surface shape of the glossy surface (S surface) of the carrier foil. Recently, as semiconductor substrates are increasingly required to be thinner and smaller, the thickness of the ultra-thin copper foil attached to the carrier foil is gradually becoming thinner and higher thickness uniformity is required. However, the conventional carrier foil attached foil has a problem in that when an ultra-thin copper foil with a thickness of 1.0 μm or less is formed on the carrier foil, it cannot secure the uniformity of the ultra-thin copper foil due to the occurrence of pinholes and unevenness caused by the polishing texture.

[0004] Accordingly, the present invention has been devised to solve the above-described problems, and the purpose of the present invention is to provide a carrier foil attachment foil having an ultra-thin copper foil having a high thickness uniformity.

[0005] In addition, the present invention aims to provide a carrier foil attachment foil having an ultra-thin copper foil in which the formation of pinholes and unevenness is suppressed.

[0006] In addition, the present invention aims to provide a carrier foil attachment foil having an ultra-thin copper foil with a low-impact, smooth surface.

[0007] In addition, the present invention aims to provide a carrier foil attachment foil having a stable peel strength by implementing a uniform laminated structure of the carrier foil attachment foil.

[0008] In addition, the present invention aims to provide a carrier foil attachment foil suitable for the required properties of copper foil, such as high-temperature peel strength, chemical resistance, and etching properties.

[0009] In addition, the present invention aims to provide a method for manufacturing the carrier foil attachment foil described above.

[0010] In order to achieve the above technical task, the present invention provides a carrier foil attachment foil in which a carrier foil, a peeling layer, and an ultra-thin copper foil are sequentially laminated, wherein the carrier foil includes an electrolytically polished surface on a surface facing the peeling layer.

[0011] In the present invention, the ultra-thin copper foil may have a thickness of 0.5 to 1.5 μm.

[0012] Additionally, in the present invention, the surface of the ultra-thin copper foil may have an average roughness Sz of 0.45 to 0.75 ㎛.

[0013] In the present invention, the electrolytically polished surface of the carrier foil may have a roughness reduction rate of 40% or more before and after electrolytic polishing. Furthermore, in one embodiment of the present invention, the roughness reduction rate of the carrier foil may reach up to 65%.

[0014] In order to achieve the above other technical tasks, the present invention provides a method for manufacturing a carrier foil attachment foil, comprising the steps of: providing a carrier foil; electrolytically polishing a surface of the carrier foil; forming a peeling layer on the electrolytically polished carrier foil; forming a heat-resistant layer on the peeling layer; and forming an ultra-thin copper foil on the heat-resistant layer.

[0015] In the present invention, the electropolishing step may include a step of providing an electrolyte solution containing phosphoric acid and citric acid; and a step of performing electropolishing in the electrolyte solution using the carrier foil as an anode and a dimensionally stable electrode as a cathode.

[0016] In the present invention, it is preferable that the phosphoric acid concentration in the electrolyte is 250 to 450 g / L.

[0017] Additionally, in the present invention, it is preferable that the citric acid concentration in the electrolyte is 200 to 350 g / L.

[0018] In addition, it is preferable that the current density in the electrolytic polishing step of the present invention be 25 to 35 A / dm2.

[0019] Additionally, in the present invention, it is preferable that the processing time in the electrolytic polishing step is 15 to 25 s.

[0020] According to the present invention, it is possible to provide a carrier foil attachment foil having an ultra-thin copper foil having a high thickness uniformity.

[0021] In addition, according to the present invention, it is possible to provide a carrier foil attachment foil having an ultra-thin copper foil in which the formation of pinholes and unevenness is suppressed.

[0022] In addition, according to the present invention, it is possible to provide a carrier foil attachment foil having an ultra-thin copper foil with a low-light, smooth surface.

[0023] In addition, according to the present invention, by implementing a uniform laminated structure of the carrier foil attachment foil, it is possible to provide a carrier foil attachment foil having a stable peel strength.

[0024] In addition, according to the present invention, it is possible to provide a carrier foil attachment foil suitable for the required properties of copper foil, such as high-temperature peel strength, chemical resistance, and etching resistance.

[0025] FIG. 1 is a diagram schematically illustrating a laminated structure of a carrier foil attachment foil according to one embodiment of the present invention.

[0026] Figure 2 is a graph showing the results of measuring the potential difference between the cathode and the anode during electropolishing treatment according to this embodiment.

[0027] Figure 3 (a) is an electron microscope photograph of the surface of a carrier foil that has undergone electropolishing according to one embodiment of the present invention, and Figure 3 (b) is a photograph of the surface of an ultra-thin copper foil.

[0028] Figure 4 (a) is a surface photograph of a carrier foil in a comparative example of the present invention, and (b) is a surface photograph of an ultra-thin copper foil.

[0029] Figures 5 (a) and (b) are cross-sectional photographs of carrier foil attachment foil in an exemplary embodiment and a comparative example of the present invention, respectively.

[0030] Figures 6 (a) and (b) are photographs showing three-dimensional images obtained from the surfaces of samples of an exemplary embodiment and a comparative example of the present invention, respectively.

[0031] Figures 7 (a) to (e) are electron microscope photographs of the surface of ultra-thin copper foils of exemplary embodiments of the present invention, respectively.

[0032] Figures 8 (a) to (f) are electron microscope photographs of the surfaces of ultra-thin copper foils of comparative examples of the present invention, respectively.

[0033] The embodiments described herein and the configurations depicted in the drawings are merely the most preferred embodiments of the present invention and do not represent the entire technical scope of the present invention. Therefore, it should be understood that various equivalents and modifications may be substituted for them. Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0034] In the present invention, the term "lamination" means adhering at least two layers together. For example, lamination of a first layer and a second layer includes not only cases where the first layer and the second layer are in direct contact, but also cases where an additional third layer is interposed between the first layer and the second layer and adhering to the first layer and the second layer. Furthermore, in the laminated structure of the present invention, the presence of the first layer on the second layer includes cases where the first layer is in direct contact with the second layer above the second layer or contacts the second layer with a third layer interposed therebetween. Similarly, in the laminated structure of the present invention, the presence of the third layer between the first layer and the second layer includes cases where the third layer is in direct contact with the first layer and the second layer, or where the third layer is not in direct contact with the first layer or the second layer.

[0035] FIG. 1 is a diagram schematically illustrating a laminated structure of a carrier foil attachment foil according to one embodiment of the present invention.

[0036] First, referring to FIG. 1, the carrier foil attachment foil has a structure in which a carrier foil (110), a peel layer (120), a heat-resistant layer (130), and an ultra-thin copper foil (140) are sequentially laminated.

[0037] The carrier foil (110) serves as a support material (carrier) until the ultra-thin copper foil is bonded to the insulating substrate. The carrier foil may be an aluminum foil, a stainless steel foil, a titanium foil, a copper foil, or a copper alloy foil. For example, an electrolytic copper foil, an electrolytic copper alloy foil, a rolled copper foil, or a rolled copper alloy foil may be used. Preferably, the carrier foil may be an electrolytic copper foil, and the upper surface of the carrier foil may be either a glossy side (S-side, shiny side) or a matte side (M-side, matt side). In addition, a roughening treatment layer (112) may be formed on the lower surface of the carrier foil (110).

[0038] The carrier foil (110) may have a thickness of 1 mm or less. For example, the thickness of the carrier foil may be 7 to 70 ㎛. For example, the thickness of the carrier foil may be 12 to 18 ㎛. If the thickness of the carrier foil is less than 7 ㎛, it may be difficult to perform its role as a carrier, and if the thickness of the carrier foil is more than 1 mm, there is no problem in performing its role as a carrier, but when continuously plating to form a peeling layer and an ultra-thin copper foil, etc., it is necessary to increase the tension of the foil within the continuous plating line, and large-scale equipment may be required.

[0039] Preferably, the laminated structure of the present invention can be formed on the shiny side (S-side) of the carrier foil (110). The production of a low-luminance carrier foil requires a lot of cost. The present invention enables the implementation of extremely low-luminance on the S-side of the carrier foil, which has relatively high luminance.

[0040] The glossy side of the carrier foil refers to the side that comes into contact with the drum during the electroplating manufacturing process of the carrier foil, and the matte side (M side) refers to the side opposite to the drum. The glossy side of the carrier foil can be implemented as a low-roughness, smooth surface. For example, the roughness of the glossy side of the carrier foil before the electropolishing treatment described below is preferably Sz<1.5 um or less. The Rz value measured by the conventional contact-type roughness measurement method is difficult to measure a state such as a very fine pinhole depending on the size of the measuring tip that makes contact. Therefore, in the present invention, the surface roughness can be measured as Sz, which precisely measures the surface shape from the interference pattern signal through a white light interferometer.

[0041] In the present invention, the surface of the carrier foil, preferably the glossy surface of the carrier foil, is smoothed through electrolytic polishing.

[0042] In the present invention, in order to form the electrolytic polishing surface of the carrier foil, electrolytic polishing treatment, for example, electrolytic polishing treatment can be performed with the carrier foil as the anode in an aqueous solution containing phosphoric acid or citric acid.

[0043] In the present invention, the electrolytically polished surface of the carrier foil may have a roughness reduction rate of 40% or more before and after electrolytic polishing. Furthermore, in one embodiment of the present invention, the roughness reduction rate of the carrier foil may reach up to 65%.

[0044] In the present invention, the electropolishing process conditions are as follows.

[0045] Electropolishing can be performed by electropolishing the surface of the carrier foil in an electrolyte using a carrier foil as the anode and a dimensionally stable electrode (DSE) as the cathode.

[0046] The electrolyte may contain phosphoric acid and citric acid. In the present invention, the concentration of phosphoric acid in the electrolyte is preferably 500 g / L or less, 450 g / L or less, or 400 g / L or less. In addition, in the present invention, the concentration of phosphoric acid is preferably 250 g / L or more. If the concentration of phosphoric acid is less than 250 g / L, the electropolishing efficiency decreases, so that electropolishing may not be performed properly, and thus the peeling between the carrier foil and the ultra-thin film may not be performed properly. If the concentration of phosphoric acid exceeds 500 g / L, there is no problem with the electropolishing efficiency, but the manufacturing cost may increase.

[0047] In addition, in the present invention, the concentration of citric acid in the electrolyte is preferably 50 g / L or more, 100 g / L or more, 150 g / L or more, or 200 g / L or more. In addition, the concentration of the citric acid is preferably 500 g / L or less, 450 g / L or less, 400 g / L or less, or 350 g / L or less. When the concentration of citric acid is less than 50 g / L, the electropolishing efficiency decreases, so that electropolishing is not performed properly, and thus the peeling between the carrier foil and the ultra-thin film may not be performed properly. In addition, when the concentration of citric acid exceeds 500 g / L, the viscosity of the electropolishing solution increases, which may cause the voltage to increase, which may become a reason for the increase in manufacturing cost.

[0048] In the present invention, the current density during electropolishing is preferably 25 to 35 ASD. If the current density is less than 25 ASD, the electropolishing efficiency decreases, so that electropolishing is not performed properly, and thus the peeling between the carrier foil and the ultra-thin film may not be performed properly. If the current density exceeds 35 ASD, the roughness may increase due to pitting occurring outside the electropolishing section, and the peeling between the carrier foil and the ultra-thin film may not be performed properly.

[0049] For the electropolishing treatment time, 15 to 25 seconds is desirable. If it is less than 15 seconds, electropolishing may not be performed properly, and the separation between the carrier foil and the ultra-thin film may not be performed properly. If the treatment time exceeds 25 seconds, unnecessary continuous electropolishing may occur, which tends to reduce the thickness of the carrier foil. This may also be a reason for the increase in manufacturing cost due to the increase in power costs.

[0050] Referring again to Figure 1, in the present invention, the peeling layer (120) is a layer for improving peelability when peeling the ultra-thin copper foil and the carrier foil. The peeling layer can be removed integrally with the carrier foil.

[0051] In the present invention, the peeling layer may include a metal or metal alloy having peelability. The peelable metal may include molybdenum or tungsten. In addition, the peeling layer (120) may include a plating catalyst. For example, the peeling layer (120) may include at least one metal selected from the group consisting of Fe, Co, and Ni.

[0052] In addition, the peeling layer may be an organic peeling layer having peelability. When the peeling layer (120) includes an organic substance, in order to have peelability, it may be formed using one or more organic agents selected from a nitrogen-containing organic compound, a sulfur-containing organic compound, and a carboxylic acid. As the nitrogen-containing organic compound, 1,2,3-benzotriazole, carboxybenzotriazole, etc. may be used, and as the sulfur-containing organic compound, mercaptobenzothiazole, thiocyanuric acid, etc. may be used. In addition, as the carboxylic acid, oleic acid, linoleic acid, etc. may be used.

[0053] Additionally, a diffusion barrier layer (not shown) may be added between the carrier foil and the peeling layer. The diffusion barrier layer suppresses copper diffusion into the peeling layer when the carrier foil attachment foil is pressed against the insulating substrate at high temperatures. Copper diffusion into the peeling layer can create a metallic bond between the carrier foil and the ultra-thin copper foil, and the strong bonding force between them can make peeling of the carrier foil difficult, and the diffusion barrier layer can suppress this reaction.

[0054] In the present invention, the heat-resistant layer (130) may include one or more elements selected from the group consisting of Ni, Co, Fe, Cr, Mo, W, Al, and P. For example, the heat-resistant layer may be a single metal layer, an alloy layer of two or more metals, or a layer of one or more metal oxides. In the present invention, the heat-resistant layer (130) may be formed by sputtering, electroplating, or electroless plating.

[0055] For example, as a plating forming a single metal layer as the heat-resistant layer, nickel plating, cobalt plating, iron plating, aluminum plating, etc. can be used. As a plating forming a binary alloy layer, nickel-cobalt plating, nickel-iron plating, nickel-chromium plating, nickel-molybdenum plating, nickel-tungsten plating, nickel-copper plating, nickel-phosphorus plating, cobalt-iron plating, cobalt-chromium plating, cobalt-molybdenum plating, cobalt-tungsten plating, cobalt-copper plating, cobalt-phosphorus plating, etc. can be used. Plating forming a ternary alloy layer includes nickel-cobalt-iron plating, nickel-cobalt-chromium plating, nickel-cobalt-molybdenum plating, nickel-cobalt-tungsten plating, nickel-cobalt-copper plating, nickel-cobalt-phosphorus plating, nickel-iron-chromium plating, nickel-iron-molybdenum plating, nickel-iron-tungsten plating, nickel-iron-copper plating, nickel-iron-phosphorus plating, nickel-chromium-molybdenum plating, nickel-chromium-tungsten plating, nickel-chromium-copper plating, nickel-chromium-phosphorus plating, nickel-molybdenum-tungsten plating, nickel-molybdenum-copper plating, nickel-molybdenum-phosphorus plating, nickel-tungsten-copper plating, nickel-tungsten-phosphorus plating, nickel-copper-phosphorus plating, cobalt-iron-chromium plating, cobalt-iron-molybdenum plating, cobalt-iron-tungsten plating, Cobalt-iron-copper plating, cobalt-iron-phosphorus plating, cobalt-chromium-molybdenum plating, cobalt-chromium-tungsten plating, cobalt-chromium-copper plating, cobalt-chromium-phosphorus plating, cobalt-molybdenum-phosphorus plating, cobalt-tungsten-copper plating, cobalt-molybdenum-phosphorus plating, cobalt-tungsten-copper plating, cobalt-tungsten-phosphorus plating, cobalt-copper-phosphorus plating, etc. can be used.

[0056] Preferably, in the present invention, the heat-resistant layer (130) may include Ni and P.

[0057] In the present invention, the ultra-thin copper foil (140) may have a thickness of 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, or 1 μm or less. For example, the ultra-thin copper foil may have a thickness of 0.5 μm or more. When the thickness of the ultra-thin copper foil is 1 μm or less, pinholes are actively generated, so it is suitable for application of the present invention. In addition, when the thickness of the ultra-thin copper foil is less than 0.3 μm, the ultra-thin formation becomes uneven, so the thickness of the ultra-thin copper foil is preferably greater than that. More preferably, the thickness of the ultra-thin copper foil is preferably 0.5 μm or more.

[0058] In the present invention, the ultra-thin copper foil may have a surface roughness (Sz) of 0.3 μm or more, 0.35 μm or more, 0.4 μm or more, or 0.45 μm or more. In addition, the ultra-thin copper foil may have a surface roughness (Sz) of 0.9 μm or less, 0.85 μm or less, 0.8 μm or less, or 0.75 or less.

[0059] In the present invention, the ultra-thin copper foil may have a roughened surface and an unroughened surface depending on the intended use. The roughened surface may be formed through nodulation treatment, and the unroughened surface may be formed by adding a brightener and an inhibitor during the formation of the copper foil.

[0060] In the present invention, the surface of the ultra-thin copper foil may be additionally surface-treated. Examples thereof include heat- and chemical-resistant treatment, chromate treatment, and silane coupling treatment, or a combination thereof. The type of surface treatment to be applied may be appropriately selected depending on the subsequent process.

[0061] Heat- and chemical-resistant treatments can be achieved by forming a thin film of one or more metals, such as nickel, tin, zinc, chromium, molybdenum, and cobalt, or their alloys, on a metal foil by sputtering, electroplating, or electroless plating. From a cost perspective, electroplating is preferred.

[0062] For chromate treatment, an aqueous solution containing hexavalent to trivalent chromium ions can be used. Chromate treatment can be performed by simple immersion, but is preferably performed by cathodic treatment. For example, cathodic treatment is preferably performed under the following conditions: sodium dichromate at 0.1 to 70 g / L, pH 1 to 13, bath temperature 15 to 60°C, current density 0.1 to 5 A / dm2, and electrolysis time 0.1 to 100 seconds. Furthermore, chromate treatment is preferably performed on top of a rust prevention treatment, thereby further improving moisture and heat resistance.

[0063] As the silane coupling agent used in the silane coupling treatment, for example, one or more substances or mixtures selected from the group consisting of epoxy-functional silanes such as 3-glycidoxypropyl trimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, amino-functional silanes, olefin-functional silanes, acrylic-functional silanes, methacryl-functional silanes, and mercapto-functional silanes may be used. For example, the silane coupling agent is dissolved in a solvent such as water at a concentration of 0.1 to 15 g / L and applied to a metal foil at a temperature of room temperature to 70°C or adsorbed by electrodeposition. After the silane coupling treatment, a stable bond can be formed by heating, ultraviolet irradiation, etc. Heating can be performed at a temperature of 100 to 200°C for 2 to 60 seconds.

[0064] Hereinafter, the present invention will be described in more detail with examples. However, these examples are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any way.

[0065] <Example 1>

[0066] A carrier foil attachment foil having an ultra-thin copper foil was manufactured according to the formation conditions and processing conditions of the following laminated structure.

[0067] A. Carrier Park

[0068] The surface roughness (Sz) of the glossy surface of the carrier foil was 1.29㎛, and an electrolytic copper foil with a gloss of 56.7 and a thickness of 18㎛ was used.

[0069] B. Electrolytic polishing of the carrier foil surface

[0070] Electrolytic polishing was performed in an electrolyte solution using the carrier film as the anode and the DSE as the cathode.

[0071] The electrolyte and electropolishing conditions are as follows.

[0072] - Phosphoric acid concentration: 400g / L

[0073] -Citric acid concentration: 300g / L

[0074] -Temperature: 40 ℃

[0075] -Current density: 30A / dm2

[0076] -Processing time: 20s

[0077] Fig. 2 is a graph showing the results of measuring the potential difference between the cathode and the anode under a constant current condition of 30 A / dm2 during the electropolishing treatment of this embodiment. As shown in Fig. 2, the treatment process goes through an etching section (a), a passive film formation section (b), and an electropolishing section (c) as the treatment time elapses. As shown, a passive film is not formed during electropolishing, and an increase in roughness may occur due to etching. Electropolishing forms a passive film on the surface of the copper foil, enabling surface polishing.

[0078] C. Peeling layer

[0079] In a plating bath under the following conditions, an organic peeling layer was formed on the glossy surface of the carrier film.

[0080] -Carboxybenzotriazole concentration: 1~5g / L

[0081] -Copper concentration: 5~15g / L

[0082] -H2SO4 concentration: 150g / L

[0083] -Temperature: 40 ℃

[0084] -Dipping time: 25 seconds

[0085] D. Heat-resistant layer

[0086] A heat-resistant layer was formed by Ni plating in a plating bath under the following conditions.

[0087] -Ni concentration: 15~25g / L

[0088] -P concentration 10~20g / L

[0089] -pH 4.0

[0090] -Temperature: 30 ℃

[0091] -Current density: 0.5A / dm2

[0092] -Plating time: 6 seconds

[0093] E. Ultra-thin copper foil

[0094] A copper foil with a thickness of 0.5 μm was formed in a plating bath under the following conditions.

[0095] -CuSO4-5H2O: 250g / L

[0096] -H2SO4: 100g / L

[0097] -Temperature: 35 ℃

[0098] -Current density: 20A / dm2

[0099] -Plating time: 7.5 seconds

[0100] F. Additional processing

[0101] The surface of the ultra-thin copper foil was additionally treated with heat and chemical resistance, chromate treatment, and silane coupling treatment.

[0102]

[0103] H. Characteristic Evaluation

[0104] The roughness (Sz), roughness reduction rate, gloss, peeling surface characteristics, and peel strength of the manufactured carrier film attachment foil were evaluated. The evaluation conditions for each characteristic are as follows.

[0105] a. Illuminance (Sz)

[0106] After forming an ultra-thin copper foil and peeling off the carrier foil, the roughness of the peeled surface of the ultra-thin copper foil was measured. The measurement conditions were as follows.

[0107] - Analysis equipment: NV-2200 (Nanosystemz)

[0108] - FOV Lens: 1.0x (Default)

[0109] - Interference lens: 50x

[0110] - Illumination: White Light LED Illumination

[0111] - Vertical Scanning Range: Max. 270um

[0112] - Vertical Resolution: WSI (0.5nm) / PSI (0.1nm)

[0113] - Lateral Resolution: 0.2 ~ 4um

[0114] b. Illumination reduction rate

[0115] The roughness (Sz) of the glossy surface of the carrier foil was measured, and the roughness reduction rate was calculated according to the following formula.

[0116] Roughness reduction rate = (Roughness measurement value of peeled surface after forming ultra-thin copper foil / Roughness measurement value of carrier foil before electropolishing) * 100

[0117] c. Gloss

[0118] - Measuring equipment: Gloss Metal VG 7000, NIPPON DENSHOKU

[0119] - Measurement standard: Gs(60°), JIS Z 871-1997

[0120] d. Evaluation of peeling surface characteristics

[0121] After forming the ultra-thin copper foil and peeling off the carrier foil, the presence of pinholes and unevenness on the peeled surface of the ultra-thin copper foil was checked. When the surface was observed using SEM on a sample area of ​​5x5 cm, if there were no pinholes (holes and tears) or unevenness (protrusions) larger than 0.1 ㎛, the characteristics were judged to be good.

[0122] e. Peel strength

[0123] A Teflon resin with a thickness of 50 ㎛ was prepared, and a copper foil specimen with a width of 30 mm was prepared, and a sample was prepared by pressing it on the resin at a temperature of 240℃. The pressing conditions were a pressure of 4.9 MPa and a holding time of 60 minutes, and the adhesive strength of the prepared sample was measured using the 90° peeling method according to JIS C 6471 8.1.

[0124] f. SEM analysis

[0125] After forming the ultra-thin copper foil and peeling off the carrier film, the ultra-thin copper foil peel surface was analyzed using SEM. The analysis equipment and conditions are as follows.

[0126] - Analysis equipment: EM-30N (JNY solution)

[0127] - Magnification: 5,000 X

[0128] - Vacuum mode: HV mode

[0129] - Electron Source: Pre-centered Tungsten Filament

[0130] - Tilt(°): 45°

[0131] g. FIB (Focused Ion Beam) analysis

[0132] After forming the ultra-thin copper foil, FIB analysis was performed from the ultra-thin copper foil surface to the exposed portion of the carrier foil. The analysis equipment and conditions were as follows.

[0133] - Analysis equipment: Quanta 3D FEG (FEI company)

[0134] - Magnification: 20,000~50,000

[0135] - Vacuum mode: HV mode

[0136] - Electron Source: Schottky Field Emission

[0137] - Ion Optic Resolution: 7nm@30kV

[0138] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the bonding surface with the carrier foil, was 0.54 um, the roughness (Sz) reduction rate was -58%, and the glossiness was 329.5, which were very good. There were no pinholes or unevenness when peeling the 0.5 um ultra-thin copper foil, and the peel strength was 15-20 gf / cm, which was very good.

[0139] <Example 2>

[0140] A carrier attachment foil having the same laminated structure as Example 1 was manufactured, except that the concentration of phosphoric acid in the plating solution for electrolytic polishing treatment was set to 500 g / L.

[0141] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.47 um, the roughness (Sz) reduction rate was -63%, and the glossiness was 410.1, which were very good. There were no pinholes or unevenness when peeling the 0.5 um ultra-thin copper foil, and the peel strength was 15-20 gf / cm, which was very good.

[0142] <Example 3>

[0143] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the concentration of phosphoric acid in the plating solution for electrolytic polishing treatment was set to 300 g / L.

[0144] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.53 um, the roughness (Sz) reduction rate was -58%, and the glossiness was 329.9, which were very good. There were no pinholes or unevenness when peeling the 0.5 um ultra-thin copper foil, and the peel strength was 15-20 gf / cm, which was very good.

[0145] <Example 4>

[0146] A carrier attachment foil having a laminated structure similar to that of Example 1 was manufactured and its characteristics were evaluated, except that an inorganic peeling layer was formed by Mo-Ni-Fe plating instead of an organic peeling layer. The plating solution and peeling layer formation conditions were as follows.

[0147] -Mo concentration: 10~30g / L, Ni concentration: 3~10g / L, Fe concentration: 1~5g / L, Sodium citrate concentration: 100~200g / L

[0148] -pH 10.2 (30ml / L ammonia water added)

[0149] -Temperature: 30 ℃

[0150] -Current density: 8 A / dm2

[0151] -Plating time: 6 seconds

[0152] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.54 um, the roughness (Sz) reduction rate was -58%, and the glossiness was 248.7, which were very good. There were no pinholes or unevenness when peeling the 0.5 um ultra-thin copper foil, and the peel strength was 15-20 gf / cm, which was very good.

[0153] <Example 5>

[0154] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the concentration of citric acid in the electrolyte for electropolishing was set to 250 g / L.

[0155] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.57 um, the roughness (Sz) reduction rate was -55%, and the glossiness was 213.7, which were very good. There were no pinholes or unevenness when peeling the 0.5 um ultra-thin copper foil, and the peel strength was 15-20 gf / cm, which was very good.

[0156] <Example 6>

[0157] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the concentration of phosphoric acid in the electrolyte for electropolishing was set to 300 g / L and the concentration of citric acid was set to 250 g / L.

[0158] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.74 um, the roughness (Sz) reduction rate was -43%, and the glossiness was 182.9, which were very good. There were no pinholes or unevenness when peeling the 0.5 um ultra-thin copper foil, and the peel strength was 15-20 gf / cm, which was very good.

[0159] <Comparative Example 1>

[0160] A carrier attachment foil having the same laminated structure as Example 1, except that the electrolytic polishing treatment was omitted, was manufactured and its characteristics were evaluated.

[0161] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 1.30 um, the roughness (Sz) decrease rate was +0.8%, and the glossiness was 52.7, indicating an increase in roughness and a decrease in glossiness. When peeling off the 0.5 um ultra-thin copper foil, pinholes and unevenness were observed, and the peeling between the carrier foil and the ultra-thin foil was unstable.

[0162] Comparative Example 2

[0163] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the concentration of phosphoric acid in the plating solution during electropolishing treatment was set to 200 g / L.

[0164] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.93 um, the roughness (Sz) reduction rate was -27%, and the glossiness was 90.8, showing a decrease in roughness and an increase in glossiness. There were no pinholes when the 0.5 um ultra-thin copper foil was peeled, but since the electropolishing was not perfectly performed, there were unevenness, making the peeling between the carrier foil and the ultra-thin copper foil unstable.

[0165] <Comparative Example 3>

[0166] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that citric acid was not added to the plating solution during electrolytic polishing.

[0167] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 0.88 um, the roughness (Sz) reduction rate was -31%, and the glossiness was 99.1, showing a decrease in roughness and an increase in glossiness. There were no pinholes when the 0.5 um ultra-thin copper foil was peeled, but since the electropolishing was not perfectly performed, there were unevenness, making the peeling between the carrier foil and the ultra-thin copper foil unstable.

[0168] Comparative Example 4

[0169] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the current density during electropolishing was set to 20 A / dm2.

[0170] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 1.08 um, the roughness (Sz) reduction rate was -16%, and the glossiness was 54.7, showing a decrease in roughness but a decrease in glossiness. There were no pinholes when peeling the 0.5 um ultra-thin copper foil, but since the electropolishing was not perfectly performed, there were unevenness, making the peeling between the carrier foil and the ultra-thin foil unstable.

[0171] Comparative Example 5

[0172] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the treatment time during the electropolishing treatment was set to 10 s.

[0173] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 1.75 um, the roughness (Sz) reduction rate was +35%, and the glossiness was 6.8, showing an increase in roughness and a decrease in glossiness. When peeling the 0.5 um ultra-thin copper foil, pinholes and unevenness existed, causing the ultra-thin foil to tear, resulting in unstable peeling between the carrier foil and the ultra-thin foil.

[0174] Comparative Example 6

[0175] A carrier attachment foil having the same laminated structure as Example 1 was manufactured and its characteristics were evaluated, except that the current density during electropolishing was set to 40 A / dm2.

[0176] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 2.52 um, the roughness (Sz) reduction rate was +95%, and the glossiness was 4.7, showing an increase in roughness and a decrease in glossiness. When peeling off the 0.5 um ultra-thin copper foil, pinholes and unevenness existed, causing the ultra-thin foil to tear, making the peeling between the carrier foil and the ultra-thin foil unstable.

[0177] <Comparative Example 7>

[0178] A carrier attachment foil was manufactured according to the method described in Example 1, but instead of the electrolytic polishing treatment of Example 1, a surface treatment layer was formed using the acid treatment method described in Example 1 of Korean Patent Publication No. 2023-46855.

[0179] As a result of the measurement, the roughness (Sz) of the ultra-thin copper foil, which is the attachment surface to the carrier foil, was 1.33 um, the roughness (Sz) decrease rate was +3%, and the glossiness was 14.4, showing an increase in roughness and a decrease in glossiness. When peeling off the 0.5 um ultra-thin copper foil, pinholes and unevenness were present, and the peeling between the carrier foil and the ultra-thin foil was unstable.

[0180] Table 1 below summarizes the evaluation results for samples of examples and comparative examples.

[0181] Classification Illuminance (Sz) Illuminance (Sz) Reduction Rate Gloss Pinhole Unevenness Example 10.54-58% 329.5 Good Good Example 20.47-63% 410.1 Good Good Example 30.53-58% 329.9 Good Good Example 40.54-58% 248.7 Good Good Example 50.57-55% 213.7 Good Good Example 60.74-43% 182.9 Good Good Comparative Example 11.30 0.8% 52.7 Occurrence Occurrence Comparative Example 20.93-27% 90.8 Good Occurrence Comparative Example 30.88-31% 99.1 Good Occurrence Comparative Example 41.08-16% 54.7 Good Occurrence Comparative Example 51.75+35%6.8 occurrence occurrence comparison example 62.52+95%4.7 occurrence occurrence comparison example 71.33+3%14.4 occurrence occurrence

[0182] Figure 3 (a) is an electron microscope photograph of the surface of the carrier foil that was electropolished in Example 1, and (b) is a photograph of the surface of the ultra-thin copper foil.

[0183] For comparison, the surface photograph of the carrier foil in Comparative Example 1 (Fig. 4 (a)) and the surface photograph of the ultra-thin copper foil (Fig. 4 (b)) are shown together in Fig. 4.

[0184] Referring to FIGS. 3 and 4, it can be seen that polishing marks exist on the surface of the carrier foil before electropolishing (see FIG. 4 (a)), and as shown in FIG. 4 (b), it can be confirmed that the polishing marks are removed and a smooth surface is achieved after electropolishing. Accordingly, it can be seen that the surface pinholes (see solid arrows) and unevenness (dotted arrows) of the ultra-thin copper foil that existed in Comparative Example 1 do not exist in Example 1, and the surface of the ultra-thin copper foil forms a smooth surface with extremely low roughness.

[0185] Figures 5 (a) and (b) are cross-sectional photographs of the carrier foil attachment foils of Example 1 and Comparative Example 1, respectively, showing the ultra-thin copper foil portion. As shown in Figure 5 (b), in the case of Comparative Example 1, the uneven shape of the carrier foil due to the drum grinding is maintained on the peeled surface of the ultra-thin copper foil, resulting in a decrease in thickness uniformity, whereas in the case of Example 1, a very high thickness uniformity is achieved.

[0186] Figures 6 (a) and (b) are photographs showing three-dimensional images obtained from samples of Example 1 and Comparative Example 1, respectively.

[0187] Figures 7 (a) to (e) are electron microscope photographs observing the surface of ultra-thin copper foils of samples of Examples 1 to 5 of the present invention, and Figures 8 (a) to (f) are electron microscope photographs observing the surface of ultra-thin copper foils of samples of Comparative Examples 1 to 6.

[0188] Referring to the drawings, it can be seen that the samples of Examples 1 to 5 can obtain a smooth surface without pinholes or unevenness. In contrast, the samples of Comparative Examples 1 to 6 all show significant unevenness, and it can be seen that pinholes occur in Comparative Examples 1, 5, and 6.

[0189] As described above, the present invention has been described with specific details such as specific components and limited examples and drawings, but these are provided only to help a more general understanding of the present invention, and the present invention is not limited to the above-described examples, and those with ordinary skill in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the spirit of the present invention should not be limited to the described examples, and all technical ideas that are equivalent or equivalent to the claims described below as well as the claims should be interpreted as being included in the scope of the rights of the present invention.

[0190] The present invention can be applied to a carrier foil attachment foil for a semiconductor substrate.

Claims

1. A carrier foil attachment foil in which a carrier foil, a peel layer, and an ultra-thin copper foil are sequentially laminated, The carrier foil is a carrier foil attachment foil including an electrolytic polishing surface on the surface facing the peeling layer.

2. In paragraph 1, The above ultra-thin copper foil is a carrier foil attachment foil having a thickness of 0.5 to 1.5 μm.

3. In paragraph 1, The surface of the above ultra-thin copper foil is a carrier foil attachment foil having an average roughness Sz of 0.45 to 0.75 ㎛.

4. In paragraph 1, The electrolytically polished surface of the carrier foil is a carrier foil attachment foil having a roughness reduction rate of 40% or more before and after electrolytic polishing.

5. Step of providing a carrier box; A step of electrolytically polishing the surface of the carrier film; A step of forming a peeling layer on the electrolytically polished carrier foil; A step of forming a heat-resistant layer on the above peeling layer; A method for manufacturing a carrier foil attachment foil, comprising the step of forming an ultra-thin copper foil on the heat-resistant layer.

6. In paragraph 5, The above electropolishing step is, A step of providing an electrolyte containing phosphoric acid and citric acid; A method for manufacturing a carrier foil attachment foil, comprising a step of electrolytic polishing in the electrolyte using the carrier foil as an anode and a dimensionally stable electrode as a cathode.

7. In paragraph 6, A method for manufacturing a carrier foil-attached foil, wherein the phosphoric acid concentration in the electrolyte is 250 to 450 g / L.

8. In paragraph 7, A method for manufacturing a carrier foil-attached foil, wherein the concentration of citric acid in the electrolyte is 200 to 350 g / L.

9. In paragraph 6, A method for manufacturing a carrier foil attachment foil, wherein the current density in the above electrolytic polishing step is 25 to 35 A / dm2.

10. In paragraph 6, A method for manufacturing a carrier foil attachment foil, wherein the processing time in the above electropolishing step is 15 to 25 seconds.

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