TWI593830B - With a carrier of ultra-thin copper foil, copper-clad laminate and coreless substrate - Google Patents

Description

Very thin copper foil with carrier, copper laminated board and coreless substrate

The present invention relates to a carrier-attached ultra-thin copper foil suitable for fabricating a coreless substrate, and a copper-clad laminate comprising the ultra-thin copper foil with a carrier ultra-thin copper foil.

With the development of miniaturization and thinning of electronic devices, circuit board manufacturers are investigating the use of a thinned substrate called a coreless substrate to fabricate a multi-layer laminate, and tend to use a portion of the substrate for use in a semiconductor package or the like. Replace with a coreless substrate. However, since the coreless substrate does not have a core plate that supports the wiring layer, rigidity is lacking, and defects such as breakage, warpage, and cracking may occur during formation of the wiring layer. Therefore, a new method is being studied, in which a carrier foil with a carrier of a very thin copper foil is used as a support, a build-up circuit substrate is laminated on the side of the ultra-thin copper foil, and finally the carrier foil with the carrier ultra-thin copper foil is peeled off, and only the carrier foil is taken out. Coreless substrate.

In the build-up substrate, a high-density wiring in which a fine wiring layer (addition layer) is deposited on the core layer of the support, that is, a layer is formed. However, the above-mentioned core layer uses glass epoxy resin or the like, and the conventional printed substrate technology causes deterioration in electrical characteristics. In particular, the large inductance component of the plated through hole passing through the core layer becomes the main reason for increasing the power supply interference of the semiconductor chip. Therefore, there is an urgent need to adopt a coreless substrate without the core layer.

A specific manufacturing process for a coreless substrate with a carrier ultra-thin copper foil as a support will now be described. The coreless substrate is produced by the process of the order of FIGS. 1(a) to (g). The prepreg 4 is bonded to the ultra-thin copper foil 2 with the carrier ultra-thin copper foil 3. The carrier-attached ultra-thin copper foil 7 for forming fine wiring is bonded to the prepreg 4. The carrier foil 5 with the carrier ultra-thin copper foil for forming the fine wiring is peeled off, and the ultra-thin copper foil 6 is etched into a predetermined wiring pattern to form the fine wiring 8. The prepreg 4 is again bonded to the fine wiring 8 to complete the first layer of the coreless substrate. The process of (b) to (d) is repeated, and a coreless substrate 9 is formed on the carrier-attached ultra-thin copper foil as a support. Thereafter, the carrier foil 1 as a support is peeled off, and finally, the outermost thin copper foil 2 is removed by etching or the like, and only the coreless substrate shown in (g) is taken out.

In the manufacturing process of the coreless substrate described above, when the fine wiring formed on the inner layer is formed, an extremely thin copper foil with a carrier is also used. When the carrier foil 5 is peeled off after the process (b) of FIG. 1, if the carrier peel strength of the carrier-attached ultra-thin copper foil 3 is not high, the carrier foil 1 used as a support may be in an unexpected stage in the coreless substrate manufacturing process. Stripped. Further, when the carrier peeling strength is too high, when the coreless substrate is peeled off after the lamination process, a strong force is required, and breakage or warpage may occur on the coreless substrate to cause damage. Therefore, although a moderate adhesion is required in a manufacturing process such as plating or etching, the coreless substrate is not mechanically damaged at the time of peeling, so the carrier foil with the carrier ultra-thin copper foil 3 is peeled off from the ultra-thin copper foil 2. The peel strength of 1 is preferably from 0.05 kN/m to 0.15 kN/m.

In the peeling layer with the carrier ultra-thin copper foil, for example, the inventions described in Patent Documents 1 and 2 are not specifically made of a coreless substrate. According to the invention, the inventors believe that if these schemes are directly used for manufacturing a coreless substrate, unexpected problems may occur.

For example, in Patent Document 1 (WO2010/27052), in consideration of the temperature to which the multilayer laminated board is produced, the carrier foil and the ultra-thin copper foil can be easily peeled off even when placed in a high temperature environment of 300 ° C to 400 ° C. The main focus is on setting the peeling interface to two layers, and specifying the metal ratio of the peeling layer composed of two layers, thereby facilitating peeling.

Further, in Patent Document 2 (Japanese Laid-Open Patent Publication No. 2007-186781), the content of the two kinds of metals A and B constituting the peeling layer required for suppressing the occurrence of expansion is suppressed.

However, these solutions are contrary to the patented invention, and their development objective is to maintain the peel strength of the carrier even after pressing at a high temperature (300 ° C to 400 ° C) which is subjected to the production of the laminate. The use of such a carrier to peel the carrier copper foil with low strength to make a laminate, especially to make a coreless substrate, due to the force exerted in the lamination process, the carrier foil and the pole as the support appear in an unexpected stage in the lamination process. The risk of peeling problems between thin copper foils.

[Practical Technical Literature] [Patent Literature]

[Patent Document 1] WO2010/27052

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-186781

As described above, in order to prevent peeling of the carrier foil and the copper foil at an unexpected stage in the lamination process of the laminate, a carrier-attached ultra-thin copper foil having a high carrier peel strength is required.

In particular, there is a need for a belt having a moderately high carrier peel strength after heating at a lower temperature (mainly 150 ° C to 220 ° C required for pressing a glass epoxy substrate or a BT resin substrate) when a coreless substrate is produced. The carrier is extremely thin copper foil.

SUMMARY OF THE INVENTION An object of the present invention is to provide an ultra-thin copper foil with a carrier which satisfies this requirement, and a laminated board using the carrier-coated ultra-thin copper foil.

The carrier-attached ultra-thin copper foil of the present invention has a carrier foil; an ultra-thin copper foil; and a metal A formed between the carrier foil and the ultra-thin copper foil, which is made of a peeling property, and which facilitates the above-mentioned ultra-thin copper foil The peeling layer formed of the plated metal B is characterized in that the peeling layer includes a first peeling layer formed on the side of the carrier foil, and a second peeling layer formed on the side of the ultra-thin copper foil, the first peeling layer The layer is used to appropriately increase the peel strength of the carrier to reduce the ratio of the metal A or the compound thereof as the peeling interface. Therefore, the element ratio x1 (at%) of the metal A to the element ratio y1 (at%) of the metal B is 70 (%). <{y1/(x1+y1)}×100 79 (%), and for the same reason, the element ratio x2 (at%) of the metal A to the element ratio y2 (at%) of the metal B is set to 80 (%) <{y2/(x2+) Y2)}×100 88 (%).

The carrier-attached ultra-thin copper foil of the present invention preferably has a peeling strength of the carrier foil and the ultra-thin copper foil of 0.05 kN/m or more and 0.15 kN/m or less after heat treatment at a temperature of from 150 ° C to 220 ° C for 1 hour to 2 hours. .

In the ultra-thin copper foil with carrier of the present invention, it is preferable that the metal A is at least one metal or alloy selected from the group consisting of Mo, Ta, V, Mn, W, Cr, and an alloy containing these elements, and the metal B is from Fe, At least one metal or alloy selected from the group consisting of Co, Ni, and an alloy group containing these elements.

The carrier-attached ultra-thin copper foil of the present invention preferably has a diffusion preventing layer between the carrier foil and the release layer.

In the ultra-thin copper foil with a carrier of the present invention, it is preferable that the diffusion preventing layer is formed of at least one metal or alloy selected from the group consisting of Fe, Ni, Co, Cr, and an alloy containing these elements.

Preferably, the carrier foil of the present invention is a copper or copper alloy.

The copper-clad laminate substrate of the present invention is a copper-clad laminate substrate obtained by laminating the above-described carrier-attached ultra-thin copper foil on a resin substrate.

The ultra-thin copper foil with carrier of the invention can prevent the carrier foil and the copper foil from being peeled off at an accidental stage in the lamination process of using the ultra-thin copper foil with the carrier to form a multi-layer laminated board, thereby realizing the stabilization of the production process and the improvement of the yield. .

1‧‧‧ Carrier foil for carrier with very thin copper foil

2‧‧‧Ultra-thin copper foil with support carrier ultra-thin copper foil

3‧‧‧Ultra-thick copper foil with carrier

4‧‧‧Prepreg blanks

5‧‧‧ Carrier foil for carrier ultra-thin copper foil for forming fine wiring

6‧‧‧ Ultra-thin copper foil with very thin copper foil for the formation of fine wiring

7‧‧‧very thin copper foil with carrier for forming fine wiring

8‧‧‧Micro wiring

9‧‧‧ Coreless substrate

10‧‧‧With carrier ultra-thin copper foil

11‧‧‧Carrier foil

12‧‧‧Protection of the diffusion layer

13‧‧‧ peeling layer

14‧‧‧First peeling layer

15‧‧‧Second stripping layer

16‧‧‧very thin copper foil

Fig. 1 is a schematic view showing a manufacturing process of a coreless substrate having a carrier ultra-thin copper foil as a support.

Fig. 2 is a schematic view showing an embodiment of the ultra-thin copper foil with a carrier of the present patent.

Figure 3 is a graph showing current density conditions in electroplating when the carrier of the patented ultra-thin copper foil is fabricated.

2 is an embodiment of the ultra-thin copper foil with a carrier of the present invention. The carrier-attached ultra-thin copper foil 10 includes a carrier foil 11, a diffusion preventing layer 12 formed on the surface of the carrier foil 11, and a surface of the diffusion preventing layer 12. The peeling layer 13 and the ultra-thin copper foil 16 formed on the surface of the peeling layer 13 are formed. The release layer 13 includes a first release layer 14 formed on one side of the carrier foil and a second release layer 15 formed on one side of the ultra-thin copper foil. When the ultra-thin copper foil is peeled off from the carrier foil, the first peeling layer 14 remains on the side of the carrier foil, and the second peeling layer 15 remains on the side of the ultra-thin copper foil. Even if the release layer has only one layer structure of the first release layer 14, it is expected to achieve the same high carrier peel strength as the patent, but the first release layer 14 may be due to the next process, that is, the plating solution during copper impact plating. It is easily dissolved, so in order to prevent this from occurring, it is necessary to form the second peeling layer 15 so as not to directly contact the first peeling layer 14 with the copper impact plating solution.

As the carrier foil 11 for the carrier-attached ultra-thin copper foil 10, an aluminum foil, an aluminum alloy foil, a stainless steel foil, a titanium foil, a titanium alloy foil, a copper foil, a copper alloy foil, or the like can be generally used, but from the viewpoint of its operational convenience It is preferable to use an electrolytic copper foil, an electrolytic copper alloy foil, a rolled copper foil, or a rolled copper alloy foil.

When the carrier foil 11 as a support in the manufacturing process of the coreless substrate is made of a thin copper foil having a thickness of 7 μm or less, the mechanical strength of the carrier foil 11 is weak, and when the coreless substrate is manufactured, wrinkles or creases are likely to occur in the substrate, thereby Support It does not play a full role. Further, when the thickness of the carrier foil is 200 μm or more, the unit coil weight (coil single weight) is increased, and the production cost is increased, which is not preferable. Therefore, the thickness of the carrier foil is preferably 7 μm to 200 μm.

The peeling layer 13 is composed of a metal A that maintains peelability and a metal B that facilitates plating of an extremely thin copper foil.

The metal A constituting the above-mentioned release layer is selected from Mo, Ta, V, Mn, W, Cr, or an alloy group containing these elements. Among them, it is particularly preferable to select from Mo, Ta, V, Mn, W, or an alloy group containing these elements from the viewpoint of biosafety of the chemical solution for treatment. Further, the metal B is selected from Fe, Co, Ni, or an alloy group containing these elements.

As shown in FIG. 2, the peeling layer 13 includes a first peeling layer 14 provided on the side of the carrier foil 11, and a second peeling layer 15 provided on the side of the ultra-thin copper foil 16.

After intensive studies by the inventors, it was found that the composition ratio (element ratio) of the metal A which maintains the releasability and the metal B which facilitates electroplating of the ultra-thin copper foil in the first peeling layer 14 constituting the peeling layer 13 is set to 70 (%) < {y1/(x1+y1)}×100 79 (%), the best ratio. Further, x1 is an element ratio of the metal A, and y1 is an element ratio of the metal B.

If the ratio is 70% or less, the carrier peel strength is too low, and the carrier foil may be peeled off from the copper foil in an accidental stage during the lamination process of the laminate, and if the ratio is more than 79%, the carrier peel strength is too high. There is a problem that the extremely thin copper foil cannot be peeled off.

After intensive research by the inventors, it was found that the composition ratio (element ratio) of the metal A which maintains the releasability and the metal B which facilitates electroplating of the ultra-thin copper foil in the second peeling layer 15 constituting the peeling layer 13 is set to 80 (%) < {y2/(x2+y2)}×100 88 (%).

The ratio is the best. Further, x2 is the element ratio of the metal A, and y2 is the element ratio of the metal B.

When the ratio is 80% or less, the content of the metal B which facilitates the plating of the ultra-thin copper foil is small, and pores or expansion occur in the ultra-thin copper foil which is formed into a film, which is not preferable, and if it is 88% or more, If the carrier peel strength is too high, there is a problem that the extremely thin copper foil cannot be peeled off from the carrier foil.

Further, when two or more kinds of the same metal are contained in the metal A or the metal B, the element ratio of the same metal is added as the element ratio.

Prevent the formation of a diffusion layer

In order to stabilize the peeling property of the ultra-thin copper foil 16, a diffusion preventing layer may be formed on the surface of the carrier foil 11. When the diffusion preventing layer 12 is provided in this manner, the peeling property of the peeling layer 13 will be stable and effective. In the examples of the present patent, although Ni is used as the diffusion preventing layer, the same effect can be obtained by using Fe and Co.

Formation of peeling layer

As an example of the production of the carrier-attached ultra-thin copper foil 10, first, a diffusion preventing layer 12 for preventing diffusion of a carrier foil element is formed on the surface of the carrier foil 11, and then a first peeling layer 14 and a second peeling layer 15 are formed.

Each of the above-mentioned peeling layers 14 and 15 can be formed by electroplating.

Changing the metal composition of each of the peeling layers 14 and 15 can be achieved by changing the concentration ratio of the metal A to the metal B (electrolytic bath composition) added in the electrolytic bath.

Alternatively, the metal composition can be changed by changing the plating conditions even without changing the composition of the electrolytic bath. For example, the metal composition of each peeling layer can be changed by changing the current density.

Film formation of very thin copper foil

The formation of the ultra-thin copper foil 16 is formed by electroplating on the second release layer 15 using a copper sulfate bath, a copper pyrophosphate bath, a copper sulfamate bath, and a copper cyanide bath. In addition, depending on the different elements constituting the second release layer 15, in the plating process of the ultra-thin copper foil film, the immersion time in the plating solution, the current density, the liquid discharge after plating, the water washing, and the plating solution pH may occur. Since the second peeling layer is damaged, it is necessary to pay attention to the relationship with the elements constituting the second peeling layer for the plating bath composition, plating conditions, and the like.

Further, when the ultra-thin copper foil is formed on the second release layer, it is difficult to uniformly plate the release layer, and there may be pores or expansion on the extremely thin copper foil which is formed into a foil.

When it is difficult to perform uniform plating, first, copper impact plating can be performed on the surface of the second release layer 15 using a copper pyrophosphate bath or the like, thereby reducing the oxide of the metal A and forming a dense and dense bottom. The plating layer is then subjected to ordinary copper plating, whereby uniform plating is performed on the second peeling layer, thereby reducing the number of pores generated on the extremely thin copper foil and preventing expansion.

The thickness of the copper plating layer adhered by the above impact plating is preferably 0.01 μm to 0.5 μm, and the conditions vary depending on the bath type, and the current density is preferably 0.1 A/dm ² to 20 A/dm ² , which is preferable as the plating time. It is 0.1 second or longer. If the current density was 0.1A / dm ² or less, it is difficult to uniformly adhered on the release coating layer, in addition, if it is 20A / dm ² or more, the metal concentration of the plating solution is small strike plating, the plating will produce dark, can not be obtained A uniform copper plating layer is not preferred. When the plating time is 0.1 second or less, the time is too short for obtaining a sufficient plating layer, which is not preferable. The thickness of the copper plating layer formed by impact plating on the peeling layer is required to be a thickness which does not impair the peeling property of the peeling layer, and is preferably 0.01 to 0.5 μm. After the impact plating layer is formed, copper plating is performed to form a desired thickness as an extremely thin copper foil.

When manufacturing a coreless substrate, the temperature tolerated during the pressing process is 150 ° C to 220 ° C.

After the ultra-thin copper foil with the carrier of the embodiment passes through the temperature region, the carrier peeling strength is optimal, and the carrier peel strength is high, and the carrier peeling strength is on the ultra-thin copper foil with the carrier in the coreless substrate manufacturing process. A load such as an etching process for forming a circuit and a pressing process for laminating a layer has a strength that can be sufficiently withstood.

The peeling phenomenon of the ultra-thin copper foil with a carrier of the present invention may be caused by the presence of a peeling interface of the oxide of the metal A. After intensive studies on the principle of precipitation of the oxide of the metal A, the inventors have determined that the metal oxide as the peeling interface does not precipitate as long as it does not coexist with hydrogen. Hydrogen is generated by polarization (electroplating) at a potential lower than the hydrogen overvoltage. When the polarization is performed at a sufficiently low potential, the generation of hydrogen will be stable. When the polarization is near the hydrogen overvoltage, the generation of hydrogen will not occur. Stable, the amount of hydrogen produced will decrease when polarized at a sufficiently low potential. The potential during plating can be controlled by changing the current density. After the cathode current is increased, the potential is shifted to a lower direction. For example, in the Mo-Co alloy plating bath used in the examples of the present patent, the cathode current density is 0.4 A/dm ² and the potential is -1.12 V (vs. Ag/AgCl). /sat.KCl), unstable hydrogen production will occur from the cathode. Thereafter, if the current density is increased, the slope of the polarization curve below 1.0 A/dm ² (-1.22 V (vs. Ag/AgCl/sat. KCl)) is shown as a fixed value of -1.18 V/decade, but if When the current density is raised above 1.0 A/dm ² , the slope of the polarization curve is reduced. Compared with the slope of the polarization curve being -1.18 V/decade, the amount of hydrogen generated is sharply increased, showing stable hydrogen generation. The peel strength of the carrier specified in this patent is as shown in Fig. 3. The first peel layer is formed on the polarization curve with a potential of -1.18 V/decade slope (cathode current of 0.4 A/dm ² to 1.0 A/dm ² ). , thus achieved.

Further, only shortening the plating time can also reduce the amount of precipitation of the metal A. Therefore, it is necessary to adjust the current density and time to control the amount of precipitation of the oxide of the metal A. After re-investigating the plating conditions of Patent Documents 1 and 2, it has been determined that they are more stable conditions for hydrogen generation than the embodiment of the present patent, and electroplating is performed for a longer period of time, and the ratio of metal A in the peeling layer is higher than that of the patent application of this patent. The range is higher. On the other hand, in the embodiment of the present patent, the amount of precipitation of the oxide of the metal A is small, and the precipitation ratio of the metal B is relatively high, and by adopting the novel plating conditions, it is difficult to form a peeling surface having weak adhesion. Thereby achieving the required high peel strength.

Hereinafter, the present invention will be described in more detail by way of examples.

[Examples] [Example 1]

A copper foil (thickness: 18 μm) having a single-surface roughness Rz of 1.1 μm was used as a carrier foil, and Ni plating treatment was performed on the carrier foil to form a diffusion preventing layer.

Ni plating conditions

Ni 120g/L

H ₃ BO ₃ 30g / L

pH 3.5

Bath temperature 50 ° C

Current density 20A/dm ²

Plating time 14.8s

On the carrier foil on which the diffusion preventing layer was formed, a first peeling layer was formed using a Co-Mo plating bath at a current density of 0.4 A/dm ² and a plating time of 6.0 s.

Co-Mo plating conditions

Mo 8.0g/L

Co 4.0g/L

Trisodium citrate 60g/L

pH 5.2

Bath temperature 25 ° C

After the first release layer was formed, it was immersed in a Co-Mo solution for 5.0 s, and after being immersed in the plating solution, a second release layer was formed at a current density of 0.3 A/dm ² and a plating time of 12.0 s.

Next, the peeling layer was subjected to copper impact plating under copper pyrophosphate plating conditions, and copper plating was performed thereon under the conditions of thin copper foil plating to form an ultra-thin copper foil having a thickness of 3 μm as an ultra-thin copper foil with a carrier.

Copper pyrophosphate plating conditions

Copper pyrophosphate 19g/L

Potassium pyrophosphate 250g/L

pH 8.5

Bath temperature 40 ° C

Current density 1.2A/dm ²

Plating time 59.2s

Very thin copper foil foiling conditions

Cu 70g/L

H ₂ SO ₄ 50g/L

Cl 25ppm

Current density 16.3A/dm ²

Plating time 59.2s

[Examples 2 to 5]

An extremely thin copper foil with a carrier was produced in the same manner as in Example 1 except that the plating conditions for forming the first release layer in Example 1 and the plating conditions for forming the second release layer were changed to those shown in Table 1.

[Embodiment 6]

On the same carrier foil as in Example 1, the same diffusion preventing layer as in Example 1 was formed. On the carrier foil on which the diffusion preventing layer was formed, a first peeling layer was formed using a Mo-Fe plating bath.

Mo-Fe plating conditions

Mo 8.0g/L

Fe 3.7g/L

Trisodium citrate 60g/L

pH 4.0

Bath temperature 35 ° C

Current density 0.5A/dm ²

Plating time 6.0s

After the first release layer was formed, it was immersed in the Mo-Fe solution for 5.0 s. After immersing in the plating solution, a second release layer was formed at a current density of 0.3 A/dm ² and a plating time of 12.0 s. Then, on the peeling layer, copper impact plating and copper plating were carried out in the same manner as in Example 1 to form an ultra-thin copper foil having a thickness of 3 μm, which was used as a carrier-attached ultra-thin copper foil.

[Embodiment 7]

On the same carrier foil as in Example 1, the same diffusion preventing layer as in Example 1 was formed. On the carrier foil on which the diffusion preventing layer was formed, a first peeling layer was formed using a Mo-Ni plating bath.

Mo-Ni plating conditions

Mo 24.0g/L

Ni 11.2g/L

Trisodium citrate 60g/L

pH 10

Bath temperature 25 ° C

Current density 0.8A/dm ²

Plating time 6.0s

After the first release layer was formed, it was immersed in a Mo-Ni solution for 5.0 s. After immersing in the plating solution, a second release layer was formed at a current density of 0.3 A/dm ² and a plating time of 12.0 s. Then, on the peeling layer, copper impact plating and copper plating were carried out in the same manner as in Example 1 to form an ultra-thin copper foil having a thickness of 3 μm, which was used as a carrier-attached ultra-thin copper foil.

[Embodiment 8]

On the same carrier foil as in Example 1, the same diffusion preventing layer as in Example 1 was formed. On the carrier foil on which the diffusion preventing layer was formed, a first peeling layer was formed using a W-Ni plating bath.

W-Ni plating conditions

W 27.9g/L

Ni 11.2g/L

Trisodium citrate 60g/L

pH 10

Bath temperature 25 ° C

Current density 0.7A/dm ²

Plating time 6.0s

After the first release layer was formed, it was immersed in W-Ni liquid for 5.0 s. After immersing in the plating solution, a second release layer was formed at a current density of 0.3 A/dm ² and a plating time of 12.0 s. Then, on the peeling layer, copper impact plating and copper plating were carried out in the same manner as in Example 1 to form an ultra-thin copper foil having a thickness of 3 μm, which was used as a carrier-attached ultra-thin copper foil.

[Comparative example] [Comparative Examples 1 and 2]

On the same carrier foil as in Example 1, the same diffusion preventing layer as in Example 1 was formed. On the carrier foil on which the diffusion preventing layer was formed, the Mo-Co plating bath was used, and the amount of hydrogen gas generated was significantly reduced or increased as compared with Example 1, and the current density conditions shown in Table 1 were higher than those of the embodiment. A low potential polarization condition) forms a first release layer.

After forming the first release layer, it was immersed in Mo-Co solution for 5.0 s. After immersing in the plating solution, a second release layer was formed under the current density conditions of Table 1. Then, on the peeling layer, copper impact plating and copper plating were carried out in the same manner as in Example 1 to form an ultra-thin copper foil having a thickness of 3 μm, which was used as a carrier-attached ultra-thin copper foil.

[Comparative Examples 3 and 4]

On the same carrier foil as in Example 1, the same diffusion preventing layer as in Example 1 was formed. On the carrier foil on which the diffusion preventing layer was formed, a first peeling layer was formed under the current density conditions of Table 1 using a Mo-Co plating bath.

After forming the first release layer, it was immersed in Mo-Co solution for 5.0 s. After immersing in the plating solution, a second release layer was formed under the current density conditions of Table 1 (polarization conditions of higher potential and lower polarization conditions than the examples). Then, on the peeling layer, copper impact plating and copper plating were carried out in the same manner as in Example 1 to form an ultra-thin copper foil having a thickness of 3 μm, which was used as a carrier-attached ultra-thin copper foil.

The prepared ultra-thin copper foil with carrier is pressed at 150 ° C × 1 hour, 180 ° C × 1 hour, and 220 ° C × 2 hours, and pressed at a pressure of 30 k gf / cm ² to form an extremely thin copper foil. Adhesion to the resin substrate. Thereafter, a circuit having a width of 10 mm was produced, and the carrier foil was peeled off in a 90-degree direction using a tensile tester (manufactured by Toyo Baldwin, UTM-4-100) according to JIS C6481-1996 to measure the peel strength of the carrier. The measurement results are shown in Table 1.

The prepared ultra-thin copper foil was peeled off from the carrier foil, and the element remaining on the side of the ultra-thin copper foil and the side of the carrier foil (Mo, Co, Ni, W, Fe) was measured using a fluorescent X-ray analyzer. ) The amount of adhesion. The measurement results are shown in Table 1.

evaluation result [Examples 1 to 8]

In Examples 1 to 8, after peeling off the carrier foil and the ultra-thin copper foil, the composition of the peeling layer remaining on the carrier foil and the ultra-thin copper foil, the proportion of the metal B was 70% to 79% and 80% to 89, respectively. %. After heating at 150 ° C for 1 hour, 180 ° C for 1 hour, and 220 ° C for 2 hours, the carrier peel strength was from 0.050 kN/m to 0.150 kN/m, thereby obtaining a carrier peel strength suitable for producing a coreless substrate.

[Comparative Example 1]

In Comparative Example 1, after the carrier foil and the ultra-thin copper foil were peeled off, the proportion of the metal B remaining in the peeling layer of the carrier foil and the ultra-thin copper foil was 79.6% and 85.9%, respectively, and the metal on the side of the carrier foil. The B ratio is beyond the provisions of this patent. Therefore, after heating at 150 ° C × 1 hour, 180 ° C × 1 hour, and 220 ° C × 2 hours, the carrier peel strength is higher than 0.150 kN / m, although the high carrier peel strength is achieved, but the carrier peel strength is too high, when the carrier foil is peeled off There may be problems such as bending or breaking of the coreless substrate, and there is a problem in practical use.

[Comparative Example 2]

In Comparative Example 2, after the carrier foil and the ultra-thin copper foil were peeled off, the proportion of the metal B remaining in the peeling layer component remaining on the carrier foil was 70% or less, which was lower than the value specified in the patent. Therefore, after heating at 150 ° C for 1 hour, 180 ° C for 1 hour, and 220 ° C for 2 hours, the carrier peel strength was less than 0.050 kN/m, so that high carrier peel strength was not achieved.

[Comparative Example 3]

In Comparative Example 3, after the carrier foil and the ultra-thin copper foil were peeled off, the proportion of the metal B was 88% or more in the peeling layer component remaining on the ultra-thin copper foil, and the ratio of the metal B on the extremely thin copper foil side exceeded this. Patent regulations. Therefore, after heating at 150 ° C × 1 hour, 180 ° C × 1 hour, and 220 ° C × 2 hours, the carrier peel strength is higher than 0.150 kN / m, although the high carrier peel strength is achieved, but the carrier peel strength is too high, when the carrier foil is peeled off There may be problems such as bending or breaking of the coreless substrate, and there is a problem in practical use.

[Comparative Example 4]

In Comparative Example 4, after the carrier foil and the ultra-thin copper foil were peeled off, the proportion of the metal B was 80% or less in the peeling layer component remaining on the ultra-thin copper foil, and the ratio of the metal B on the very thin copper foil side was lower than that in Comparative Example 4 The provisions of this patent. Therefore, after heating at 150 ° C for 1 hour, 180 ° C for 1 hour, and 220 ° C for 2 hours, the carrier peel strength was less than 0.050 kN/m, so that high carrier peel strength was not achieved.

Using the ultra-thin copper foil with a carrier prepared in Example 1, the coreless substrate was produced in accordance with the above-described coreless substrate production step, and no problem occurred in the manufacturing process, and the peeling process was smoothly peeled off.

Claims (7)

An ultra-thin copper foil with a carrier having a carrier foil, an ultra-thin copper foil, and a release layer formed of a metal A and a metal B formed between the carrier foil and the ultra-thin copper foil, wherein the metal A is from Mo or One type of W is selected, and the metal B is one selected from Fe, Co, and Ni, and the release layer is composed of two layers, that is, a first release layer formed on the side of the carrier foil, and formed on The second peeling layer on the side of the ultra-thin copper foil, wherein the element ratio x1 (at%) of the metal A in the first peeling layer and the element ratio y1 (at%) of the metal B are 70 (%) <{y1/ (x1+y1)}×100 79 (%), and the element ratio x2 (at%) of the metal A in the second peeling layer and the element ratio y2 (at%) of the metal B are 80 (%) < {y2 / (x2 + y2)} × 100 88 (%). The ultra-thin copper foil with a carrier according to the first aspect of the invention, wherein the carrier foil and the ultra-thin copper foil have a peeling strength at room temperature of 0.05 after heat treatment at a temperature of 150 ° C or more and 220 ° C or less for 1 to 2 hours. kN/m or more is 0.15 kN/m or less. The ultra-thin copper foil with a carrier according to claim 1 or 2, wherein the carrier foil and the release layer have a diffusion preventing layer. The ultra-thin copper foil with a carrier according to claim 3, wherein the diffusion preventing layer is formed of at least one metal or alloy selected from the group consisting of Fe, Ni, Co, Cr, and an alloy containing these elements. . The carrier-attached ultra-thin copper foil according to claim 1 or 2, wherein the carrier foil is copper or a copper alloy. A copper-clad laminate which is obtained by laminating an ultra-thin copper foil with a carrier according to any one of claims 1 to 5 on a resin substrate. A coreless substrate, which is produced by using the carrier-used ultra-thin copper foil according to any one of claims 1 to 5.