Resin plating material and method for manufacturing the same

Abstract

To provide a resin plating material capable of improving adhesive strength between a base material and a plating layer rather than before without substantially providing unevenness on the surface of the base material.SOLUTION: A resin plating material includes: a base material including an insulating resin material; a pore layer formed to a depth of 20 nm or more from the surface of the base material, including voids having a nm order size and formed to support a catalyst; and an electroless plating layer formed in the upper layer of the base material. A part of the electroless plating layer enters into the pore layer positioned at an area between the surface of the base material and a position having a depth of 20 nm or more from the surface of the base material.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a resin plating material and a method for manufacturing the same.

Background Art

[0002] A wiring board having a wiring pattern provided on the surface of an insulating resin material is known. Conventionally, this wiring board is obtained by providing an electroless plating layer called a seed layer on a resin serving as a base material and providing an electrolytic plating layer on the upper layer thereof.

[0003] In order to obtain stable electrical characteristics, it is necessary for the resin and the electroless plating layer (seed layer) to be firmly adhered to each other. Conventionally, in order to improve the adhesion, a method of roughening the surface of the resin to provide irregularities and forming a seed layer on the surface of the resin on which the irregularities are formed is known. Due to the anchor effect resulting from the presence of the irregularities, the resin and the seed layer are firmly fixed.

[0004] By the way, in a system called 5G communication, which has been in development in recent years, extremely high-frequency electrical signals are used. Such high-frequency currents flow hardly in the central part of the conductor due to a phenomenon called the skin effect, and flow only in the surface layer part of the conductor. If there are irregularities on the surface of the conductor, as a result, the signal transmission path becomes long, and the transmission loss increases. Therefore, in particular, a wiring board that is expected to handle high-frequency signals is required to minimize the irregularities on the surface of the conductor.

[0005] Based on the above circumstances, the present inventors have proposed the techniques of Patent Documents 1 and 2 below.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] An object of the present invention is to provide a resin plating material that improves the adhesive strength between a base material and a plating layer without substantially providing irregularities on the surface of the base material as compared with the conventional one. Another object of the present invention is to provide a method for manufacturing such a resin plating material.

Means for Solving the Problems

[0008] The resin plating material according to the present invention comprises a base material containing an insulating resin material, a microporous layer formed over a depth of 20 nm or more from the surface of the base material, containing voids on the order of nm and carrying a catalyst, and an electroless plating layer formed on the upper layer of the base material, wherein a part of the electroless plating layer penetrates into the microporous layer located in a region between the surface of the base material and a depth position of 20 nm or more from the surface of the base material.

[0009] According to the above configuration, a part of the electroless plating layer penetrates into the microporous layer formed in the surface region of the base material over a depth of 20 nm or more. As a result, a nano-level anchor effect is exhibited between the base material and the electroless plating layer, and both are firmly fixed.

[0010] When using the resin plating material as a package substrate and forming fine wirings on the upper surface of this package substrate, the semi-additive method is generally used. In this method, after removing the resist formed in the wiring planned region, a wiring pattern is formed in the wiring planned region. Then, the resist formed outside the wiring planned region is removed, and the electroless plating layer formed outside the wiring planned region is etched. At this time, from the viewpoint of ensuring insulation characteristics, removal of catalyst residues is also performed.

[0011] In the above configuration, since the electroless plating layer is formed on the upper surface of the base material, the residue of the catalyst is not contained in the resin base material but is mostly contained in the electroless plating layer. Therefore, for the removal and etching of the catalyst, it may be performed on the electroless plating layer, and the progress of etching on the resin base material can be suppressed, and a decrease in the adhesion between the base material and the electroless plating layer can be suppressed.

[0012] In this specification, the "microporous layer" refers to a layer containing voids generated by cutting a part of the polymer chains of the resin material constituting the base material. These voids are on the order of nm (1 nm to several nm) in size. Note that the presence and thickness of the microporous layer can be confirmed by observing the cross-section of the resin plating material with a TEM (transmission electron microscope).

[0013] However, when the depth of the region where the electroless plating layer penetrates into the microporous layer is too deep, when wiring is formed using this resin plating material, when the wiring is energized, the ratio of the current flowing through the portion of the electroless plating layer that has penetrated into the microporous layer increases. Among the electroless plating layer, it is assumed that the region formed in the microporous layer has unevenness compared to the region formed on the upper surface of the base material, that is, the surface of the electroless plating layer. Therefore, when a high-frequency current flows, there is a possibility that minute transmission loss may occur.

[0014] From such a viewpoint, the depth range of the region where a part of the electroless plating layer penetrates into the microporous layer may be 100 nm or less.

[0015] The microporous layer may be formed over a depth of 30 nm or more from the surface of the base material.

[0016] This makes it easier to support the catalyst in the microporous layer during manufacturing.

[0017] Also, as described above, the microporous layer is a layer containing voids generated by cutting a part of the polymer chains of the resin material constituting the base material. Therefore, if the thickness of the microporous layer becomes too thick, the ratio of the region where the molecular weight is reduced in the base material increases, and the strength of the base material itself may decrease.

[0018] From such a viewpoint, the microporous layer may be formed in a region within the range between the surface of the base material and a depth position of 200 nm or less from the surface of the base material.

[0019] The method for manufacturing a resin plating material according to the present invention is step (a) of preparing the base material exhibiting thermosetting properties, step (b) of heating the base material at a temperature higher than 100°C and lower than the glass transition temperature of the base material, after step (b), irradiating the surface of the base material with ultraviolet light having a main wavelength of 200 nm or less to form voids having a size on the order of nm in the base material over a depth region of 20 nm or more from the surface of the base material, and forming the microporous layer on a part of the base material, step (c); step (d) of supporting the catalyst on the surface of the base material and in the region where the microporous layer is formed in the base material, characterized by having step (e) of forming an electroless plating layer from the surface of the base material through the catalyst.

[0020] By heating the base material at a temperature higher than 100°C and lower than the glass transition temperature of the base material, the strength of the base material is enhanced. Then, by irradiating ultraviolet light or a plasma-containing gas, a microporous layer is formed in the vicinity of the surface of the base material with enhanced strength. Therefore, when an electroless plating layer is formed through the catalyst supported thereafter, the electroless plating layer that has entered the microporous layer and the base material are stably bonded.

[0021] In particular, by heating the substrate at a temperature below the glass transition temperature, the molecular network of the resin material constituting the substrate can be maintained in a low-density state while the substrate is cured. As a result, when ultraviolet rays are subsequently irradiated, the substrate can be modified not only on the surface of the substrate but also to a certain depth position, and the thickness of the microporous layer can be ensured.

[0022] In this specification, the "main wavelength" refers to the wavelength with the highest light intensity in the spectrum of light emitted from a light source.

[0023] The method for manufacturing a resin plating material according to the present invention is step (a) of preparing the substrate, step (b) of heating the substrate at a temperature higher than 50°C and lower than the glass transition point temperature of the substrate, step (c) which is carried out together with step (b), irradiating ultraviolet rays with a main wavelength of 200 nm or less on the surface of the substrate to form voids on the order of nm in size in the substrate over a depth region of 20 nm or more from the surface of the substrate, and forming the microporous layer on a part of the substrate; step (d) of supporting the catalyst on the surface of the substrate and in the region where the microporous layer is formed in the substrate; characterized by having step (e) of forming an electroless plating layer from the surface of the substrate through the catalyst.

[0024] According to the above method, ultraviolet rays are irradiated on the substrate while heating. When the substrate is heated, the molecular activity of the functional groups of the resin material constituting the substrate is activated. When ultraviolet rays are irradiated and the bonds of the molecules constituting the resin material located on the surface are broken and the molecules are reduced in size, an exchange occurs between the low molecules present on the surface and the high molecules present at a deeper position than the surface. As a result, ultraviolet rays are irradiated on many resin materials in the depth direction of the substrate, and the thickness of the microporous layer can be increased.

[0025] Furthermore, since it is heated while forming the microporous layer, the strength of the microporous layer itself is improved. As a result, the adhesion between the electroless plating layer formed later and the substrate is improved.

[0026] In the case where the heating temperature is as low as less than 50°C, among the polymers constituting the resin material, the reaction to the side chain rather than the main chain becomes dominant. In this case, even when ultraviolet rays are irradiated while heating, voids are formed only on the surface of the substrate, and the thickness of the microporous layer cannot be ensured. From such a viewpoint, in step (b), heating is performed at a temperature higher than 50°C.

[0027] The step (a) may include a step of heating the substrate at a lower temperature than the step (b).

[0028] According to the above method, residues of the organic solvent used in the production of the substrate can be removed in advance.

Advantages of the Invention

[0029] According to the present invention, a resin plating material is realized in which the adhesive strength between the substrate and the plating layer is improved compared to the prior art without substantially providing unevenness on the surface of the substrate.

Brief Description of the Drawings

[0030]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0031] Embodiments of the resin plating material and its manufacturing method according to the present invention will be described below with appropriate reference to the drawings. Each of the following drawings is schematically illustrated, and the dimensional ratios on the drawings do not necessarily match the actual dimensional ratios. Also, the dimensional ratios may not match each other between the drawings.

[0032] [First Embodiment] The first embodiment of the resin plating material and its manufacturing method according to the present invention will be described.

[0033] FIG. 1 is a cross-sectional view schematically showing the structure of the resin plating material. As shown in FIG. 1, the resin plating material 1 includes a base material 3 and an electroless plating layer 9 formed on the surface of the base material 3 on the +Z side.

[0034] In the following drawings, the Z direction refers to the direction perpendicular to the main surface of the base material 3. The main surface of the base material 3 refers to the surface that constitutes the base material 3 and has a much larger area than other surfaces. Among the main surfaces of the base material 3, the surface on the +Z side, that is, the side on which the electroless plating layer 9 is formed, may be referred to as the "surface 3a" of the base material 3 for convenience. Also, the direction from the surface 3a of the base material 3 toward the base material 3 side (-Z direction) may be referred to as the "depth direction" for convenience.

[0035] In this embodiment, the base material 3 is a resin material that exhibits insulation and thermosetting properties. Specific examples include polyimide resin, polyurethane, phenolic resin, or epoxy resin, etc. The base material 3 may be a sheet-like film or a plate-like member.

[0036] A microporous layer 5 is formed in the base material 3 over a depth D1 from the surface 3a of the base material 3. The microporous layer 5 is a layer formed by modifying the base material 3 as described later. The depth D1 is 20 nm or more, more preferably 30 nm or more, and particularly preferably 70 nm or more. Also, the depth D1 is preferably 190 nm or less.

[0037] FIG. 2 is a drawing schematically showing the structure of the microporous layer 5. The base material 3 is formed of a polymer resin material. As described later, the microporous layer 5 corresponds to a layer in which a part of the polymer chains of the resin material is cut and oligomerized by irradiating the base material 3 with ultraviolet rays. When the polymer material is oligomerized, spaces (voids 4) are formed between the oligomers. The microporous layer 5 corresponds to a layer containing the voids 4 as a result of partial modification of the base material 3 in this way. These voids 4 are on the order of nm (1 nm to several nm) in size.

[0038] As shown in FIG. 1, a catalyst 7 is supported in the microporous layer 5 provided in the base material 3 of the resin plating material 1. The catalyst 7 may be a compound containing molecules or atoms that exhibit a catalytic effect (hereinafter referred to as a "catalyst contributing compound"). Typically, a substance containing Pd is adopted, but Ni, Ag, etc. can also be used.

[0039] As shown in FIG. 1, the electroless plating layer 9 is formed on the +Z side surface of the base material 3, and more specifically, it is located on the upper layer of the microporous layer 5. And as shown in FIG. 1, a part of the electroless plating layer 9 penetrates into the microporous layer 5 in the depth direction. More specifically, the electroless plating layer 9 penetrates into the microporous layer 5 over a region with a depth D2 from the surface of the base material 3. The depth D2 is 20 nm or more, more preferably 35 nm or more. Also, the depth D2 is preferably 100 nm or less.

[0040] The electroless plating layer 9 is typically a film made of a conductive material containing Cu, but it may also be a film made of a conductive material containing other metal elements such as Ni.

[0041] As described above, the catalyst 7 is supported in the microporous layer 5. Therefore, at the position within the microporous layer 5, metal ions containing elements constituting the electroless plating layer 9 can receive the electrons released when the reducing agent is decomposed on the catalyst 7. As a result, an electroless plating layer 9 is also formed at the position within the microporous layer 5.

[0042] That is, according to the above configuration, the electroless plating layer 9 penetrates into the microporous layer 5 over a depth D2 of 20 nm or more. Thereby, a nano-level anchor effect is exhibited between the base material 3 and the electroless plating layer 9, and the two are firmly fixed. Details will be described later with reference to the examples.

[0043] FIG. 3 is a cross-sectional view schematically showing a state in which a patterned electrolytic plating layer 11 is formed on the resin plating material 1 shown in FIG. 1. After the electrolytic plating layer 11 is formed on the upper surface of the electroless plating layer 9 with respect to the resin plating material 1 in the state shown in FIG. 1, a patterning process according to the wiring pattern is performed. As a result, a predetermined region A1 is etched in the depth direction to expose the base material 3.

[0044] Here, in the vicinity of the +Z side surface (surface 3a) of the base material 3, an electroless plating layer 9 has penetrated into the base material 3, more specifically, into the microporous layer 5. Therefore, even during etching, the etching ratio for the electroless plating layer 9 increases, and the amount of etching for the base material 3 made of a resin material can be reduced. As a result, it is possible to prevent a decrease in the adhesion between the base material 3 and the electroless plating layer 9 when forming the wiring pattern.

[0045] Returning to FIG. 1, the description will be continued. The thickness (i.e., depth D1) of the microporous layer 5 formed in the vicinity of the surface 3a of the base material 3, and the depth D2 at which the electroless plating layer 9 penetrates into the microporous layer 5 can both be confirmed by analyzing an image of the resin plating material 1 taken with a STEM (Scanning Transmission Electron Microscope). More specifically, it can be confirmed by photographing the resin plating material 1 using a STEM equipped with an EDX (Energy Dispersive X-ray Spectrometer) or an EELS (Electron Energy Loss Spectrometer) and grasping the change in the elemental composition in the depth direction.

[0046] FIG. 4 is a drawing schematically showing the result when elemental analysis of the vicinity of the surface 3a of the base material 3 of the resin plating material 1 is performed using STEM-EDX. The vertical axis represents the signal intensity, and the horizontal axis represents the distance traveled in the depth direction (-Z direction) from the side of the resin plating material 1. Hereinafter, it will be described assuming that a material containing Cu is used as the electroless plating layer 9 and a material containing Pd is used as the catalyst 7.

[0047] As will be described later, the catalyst 7 is applied by immersing the base material 3 in a solution containing the catalyst 7 in a state before the electroless plating layer 9 is formed for the purpose of growing the electroless plating layer 9. Therefore, it is assumed that the catalyst 7 is supported at the highest ratio on the surface 3a of the base material 3. From such a viewpoint, it can be determined that the depth position corresponding to the peak value of the signal intensity of Pd corresponds to the depth position of the surface 3a of the base material 3 from the analysis result of STEM-EDX. At this time, the electroless plating layer 9 is formed on the side shallower than the surface 3a.

[0048] According to FIG. 4, the presence of a Pd signal is recognized even on the side deeper than the surface 3a of the substrate 3. This suggests that a microporous layer 5 containing voids 4 is formed in the vicinity of the surface 3a of the substrate 3, and Pd as a catalyst 7 is incorporated into the voids 4 in the microporous layer 5. Then, the signal intensity of Pd attenuates as it progresses in the depth direction and eventually reaches the detection limit. The depth position where the Pd signal reaches the detection limit can be inferred to be a position where there is no microporous layer 5 containing voids 4 for supporting Pd. From such a viewpoint, the thickness D1 of the microporous layer 5 can be confirmed by the travel distance from the depth position where the signal intensity of Pd shows a peak value to the depth position where the signal intensity of Pd shows the detection limit as it progresses in the depth direction.

[0049] Furthermore, according to FIG. 4, the presence of a Cu signal is recognized even on the side deeper than the surface 3a of the substrate 3. This suggests that an electroless plating layer 9 is formed in the microporous layer 5 via the catalyst 7 incorporated into the microporous layer 5. In other words, it shows that the electroless plating layer 9 has penetrated into the substrate 3, more specifically, into the microporous layer 5 where the substrate 3 is modified.

[0050] In the microporous layer 5, the signal intensity of Cu attenuates as it progresses in the depth direction and eventually reaches the detection limit. The depth position where the Cu signal reaches the detection limit can be inferred to be a position where the formation of the electroless plating layer 9 is no longer realized. From such a viewpoint, the thickness D2 of the electroless plating layer 9 that penetrates into the substrate 3, in other words, the thickness D2 of the electroless plating layer 9 that penetrates into the microporous layer 5, can be confirmed by the travel distance from the depth position where the signal intensity of Pd shows a peak value to the depth position where the signal intensity of Cu shows the detection limit as it progresses in the depth direction.

[0051] However, the positions of the detection limits of the signal intensities of Pd and Cu may vary depending on the measurement accuracy of the STEM-EDX apparatus and the like. From this perspective, regarding the thickness D1 of the microporous layer 5 and the thickness D2 of the electroless plating layer 9 that penetrates into the base material 3, in both cases, the results obtained by elemental analysis using STEM-EDX were curves subjected to 10-point smoothing processing by the simple moving average method. Specifically, in the curve subjected to 10-point smoothing processing at equal intervals of 1 mm, the thickness D1 of the microporous layer 5 was set from the depth position where the signal intensity of Pd shows a peak value to the position where the signal intensity shows up to 2% of the peak value. Further, the thickness D2 of the electroless plating layer 9 was set from the depth position where the signal intensity of Pd shows a peak value to the position where the signal intensity shows up to 1% of the peak value of the signal intensity of Cu. Since the signal intensity of Pd is smaller than that of Cu, the noise ratio of the skirt portion with respect to the peak intensity is large. For this reason, the depth position where the signal intensity shows up to 2% of the peak value of the signal intensity of Pd was taken as the thickness of the microporous layer 5.

[0052] FIG. 5 is an example of the result of obtaining a cross-sectional image of the resin plating material 1 in the vicinity of the surface 3a of the base material 3 using STEM-EDX (manufactured by JEOL Ltd., JEM-ARM200F) and performing elemental distribution measurement by energy dispersive spectroscopy (EDS). It can be confirmed that the graph shown in FIG. 5 is approximated to the graph schematically shown in FIG. 4 in terms of its tendency.

[0053] FIG. 6 is a graph in which the graph shown in FIG. 5 is supplemented by specifying the depth (thickness) D1 of the microporous layer 5 and the depth (thickness) D2 of the electroless plating layer 9 that penetrates into the base material 3 using the method described later. In the case of the example of FIG. 6, the thickness D1 of the microporous layer 5 is 100 nm (depth region from the Pd peak position of 110 nm to the Pd end position of 210 nm), and the thickness D2 of the electroless plating layer 9 that penetrates into the base material 3 is 50 nm (depth region from the Pd peak position of 110 nm to the Pd end position of 160 nm).

[0054] From the above viewpoints, in this specification, the thickness D1 of the microporous layer 5 and the thickness D2 of the electroless plating layer 9 penetrating into the base material 3 are each defined as values measured by the following method with respect to the resin plating material 1.

[0055] First, STEM-EDX is used to measure the elemental distribution in the vicinity of the interface of the resin plating material 1. An example of the apparatus for performing the elemental distribution measurement is JEM-ARM200F (manufactured by JEOL Ltd.), but the apparatus is not limited to the above example as long as it can realize the same function.

[0056] More specifically, for example, the following method can be used. After cutting the resin plating material 1 into small pieces of about 0.3 mm square, a sample thinned to about 30 nm in thickness with an ultramicrotome (EM UC7 manufactured by Leica) is obtained, and this sample is fixed to the sample holder of the STEM apparatus. Then, STEM-EDX measurement is performed at an acceleration voltage of 200 kV to obtain elemental distribution intensity curves of Pd and Cu with the horizontal axis being the depth and the vertical axis being the elemental distribution intensity. FIG. 5 is a graph obtained by this method.

[0057] Next, for each of the elemental distribution intensity curves of Pd and Cu represented by FIG. 5, 10-point smoothing processing is performed by the simple moving average method (see FIG. 6). In the curve of Pd obtained by this smoothing processing, the position Pd1 indicating the peak value of Pd and the end position Pd2 of Pd indicating an intensity value of 2% with respect to the peak value of Pd (where Pd2 > Pd1) are respectively specified. Then, the thickness (Pd2 - Pd1) between the peak position PD1 and the end position Pd2 of Pd is used to specify the thickness D1 of the microporous layer 5.

[0058] Next, in the curve of Cu obtained by the smoothing processing, the position Cu1 indicating the peak value of Cu and the end position Cu2 of Cu indicating an intensity value of 1% with respect to the peak value of Cu (where Cu2 > Cu1) are respectively specified. Then, the thickness (Cu2 - Pd1) between the peak position Pd1 of Pd and the end position Cu2 of Cu is used to specify the thickness D2 of the electroless plating layer 9 penetrating into the base material 3.

[0059] When performing the 10-point smoothing process, any software can be used. For example, Igor Pro 9.02 (manufactured by WaveMetrics) can be used. FIG. 6 corresponds to the curve obtained using the software, but even if the software used when performing the 10-point smoothing is different, the variation range of the values of the thickness D1 and the thickness D2 remains within the range of ±3% or less.

[0060] FIG. 7 is a flowchart showing an example of the manufacturing method of the resin plating material 1 of the present embodiment. In the following description, the step numbers in FIG. 7 are appropriately referred to.

[0061] (Step #1) As shown in FIG. 8, a base material 3 made of the above-described resin material is prepared. This step #1 corresponds to step (a).

[0062] In step #1, the base material 3 may be heated at a temperature lower than that in step #2 to remove the residue of the organic solvent adhering to the surface of the base material 3. An example of the heating conditions is 100°C for 30 minutes.

[0063] (Step #2) Next, the base material 3 is heated. The heating temperature is higher than 100°C and lower than the glass transition temperature of the resin material constituting the base material 3. The heating temperature is preferably less than 160°C. An example of typical heating conditions is 140°C for 30 minutes.

[0064] By step #2, the hardness of the resin constituting the base material 3 increases. However, if the heating temperature is too high, the base material 3 becomes too hard and it becomes difficult to form the microporous layer 5 in the next step #3.

[0065] As a specific embodiment of step #2, for example, the base material 3 may be placed in a chamber including a heater and heated for a predetermined time. As another method, a method of placing the base material 3 on the upper surface of a stage equipped with a heating mechanism for a predetermined time can be adopted.

[0066] This step #2 corresponds to step (b).

[0067] (Step #3) Next, as shown in FIG. 9, the base material 3 is irradiated with ultraviolet light L1 having a main wavelength of 200 nm or less. In this embodiment, the light source of the ultraviolet light L1 is arbitrary, but preferably an Xe2 excimer lamp. As another example, the light source may be a solid light source such as an LED or a laser diode that can emit ultraviolet light L1 having a main wavelength of 200 nm or less.

[0068] Ultraviolet light near a wavelength of 185 nm is easily absorbed by oxygen (O2). Therefore, when the base material 3 made of resin is irradiated with ultraviolet light L1 in an air atmosphere, a part of the ultraviolet light L1 is absorbed by O2 in the air, and according to the following formula (1), ground state atomic oxygen O( 3 P) is generated. Note that the left side of formula (1) is a convenient notation for indicating that ultraviolet light with wavelength λ is absorbed by O2, and μ indicates the frequency of wavelength λ. O2 + hν → O ( 3 P) + O( 3 P) ···(1)

[0069] Atomic oxygen O( 3 P) reacts with O2 in the air and generates ozone (O3) according to the following formula (2). O( 3 P) + O2 → O3 ···(2)

[0070] Ozone (O3) exhibits the property of absorbing ultraviolet light. When ultraviolet light is absorbed by ozone (O3), excited state atomic oxygen O( 1 D) is generated according to the following formula (3). O3 + hν → O2 + O( 1 D) ···(3)

[0071] When ultraviolet light L1 is irradiated toward the surface 3a of the base material 3, a part of the ultraviolet light L1 is absorbed by oxygen in the atmosphere existing between the light source and the surface 3a, and atomic oxygen O( 1 D) in the excited state described above is generated.

[0072] Atomic oxygen O( 1 D) is extremely reactive. Therefore, it acts on the polymer (C m H n O k ) that constitutes the base material 3 and cuts the molecular chains. In the following formula (4), m, m', n, n, k, and k' are all integers, and m > m', n > n', and k > k'. However, it should be noted that formula (4) schematically shows the reaction and is different from the exact chemical reaction formula. C m H n O k + O( 1 D) → H2O, CO, CO2 + C m' H n' O k' ‥‥(4)

[0073] When the above reaction occurs, the bonds of the polymer of the resin material near the surface 3a of the base material 3 are cut and modified into low-molecular oligomers. As a result, as described above with reference to FIG. 2, the region near the surface 3a of the base material 3 is modified into a microporous layer 5 containing voids 4.

[0074] As described above, in step #2, the base material 3 is pre-heated. Moreover, the heating temperature is lower than the glass transition temperature of the base material 3. As a result, while maintaining the molecular network of the resin material constituting the base material 3 in a low-density state, the base material 3 is cured. Then, when the base material 3 is irradiated with ultraviolet light L1, not only the surface 3a of the base material 3 but also the base material 3 can be modified into the microporous layer 5 from the surface 3a to a depth D1.

[0075] This step #3 corresponds to step (c).

[0076] (Step #4) Next, the catalyst 7 is applied to the base material 3. As a specific example, the base material 3 is immersed in a solvent containing a catalyst contributing compound.

[0077] In step #3, a microporous layer 5 containing voids 4 is formed on the base material 3 from the surface 3a to a depth D1. Therefore, by applying the catalyst 7 to such a base material 3, the catalyst 7 is supported not only on the surface 3a of the base material 3 but also in the microporous layer 5.

[0078] This step #4 corresponds to step (d).

[0079] (Step #5) Next, as shown in FIG. 1, an electroless plating layer 9 is formed on the upper surface of the base material 3. As a specific example, the base material 3 is immersed in a plating solution containing a constituent material of the electroless plating layer 9.

[0080] By this step, an electroless plating layer 9 is formed on the upper surface of the base material 3 through the mediation of the catalyst 7. Further, the plating solution also immerses into the microporous layer 5, and since the catalyst 7 is supported also in this microporous layer 5, the electroless plating layer 9 grows also in the microporous layer 5. As a result, a part of the electroless plating layer 9 enters also inside the base material 3, more specifically, into the microporous layer 5.

[0081] This step #5 corresponds to step (e).

[0082] (Post-process) Thereafter, a post-process including a step of forming an electrolytic plating layer 11 on the upper layer of the electroless plating layer 9 is executed.

[0083] [Second Embodiment] Regarding the second embodiment of the resin plating material and its manufacturing method according to the present invention, differences from the first embodiment will be mainly described. FIG. 11 is a flowchart showing an example of the manufacturing method of the resin plating material 1 of the second embodiment, following FIG. 7.

[0084] Note that, compared with the first embodiment, the structure of the resin plating material 1 is common in this embodiment, but the manufacturing method is different.

[0085] (Step #1) Similar to the first embodiment, the base material 3 is prepared. In this embodiment, the material of the base material 3 is not limited to thermosetting resin as long as it is a resin showing insulation. Specific material examples of the base material 3 include polyimide resin, liquid crystal polymer, polystyrene, polyphenylene sulfide, polyether ether ketone, polyethylene naphthalate, cycloolefin polymer, cyclic olefin copolymer, polytetrafluoroethylene, polyurethane, phenolic resin, or epoxy resin, etc.

[0086] (Step #6) Next, ultraviolet light L1 is irradiated while heating the base material 3. For example, ultraviolet light L1 from a light source is irradiated onto the base material 3 in a state where the base material 3 is placed on a stage including a heating mechanism. As another example, the base material 3 may be installed in a chamber containing a heater and a light source, and heating of the base material 3 and irradiation of ultraviolet light L1 may be performed in parallel in the chamber.

[0087] In step #6, the heating temperature is higher than 50°C and lower than the glass transition temperature of the resin material constituting the base material 3. The heating temperature is preferably less than 160°C. An example of typical heating conditions is 100°C for 30 minutes. Regarding the heating time, it may be appropriately changed according to the type of resin material, and may be about 1 minute, for example.

[0088] By this step #6, the base material 3 can be modified into the microporous layer 5 from the surface 3a of the base material to a depth D1. In particular, by irradiating the ultraviolet ray L1 while heating, the molecular activity of the functional groups of the resin material constituting the base material can be activated, so that an exchange is likely to occur between the low molecules present on the surface 3a and the high molecules present at a position deeper than the surface 3a. As a result, a large amount of the resin material is irradiated with the ultraviolet ray L1 in the depth direction, and the thickness of the microporous layer 5 can be increased. Furthermore, this fragile microporous layer 5 can be cured, and the effect of enhancing the adhesion between the base material 3 and the electroless plating layer 9 can also be obtained.

[0089] In addition, when the heating temperature is less than 50°C, the reaction mainly occurs in the side chains rather than the main chain of the high molecules constituting the resin material. In this case, even when irradiating ultraviolet rays while heating, voids are formed only on the surface of the base material, and it becomes difficult to ensure the thickness of the microporous layer 5. From such a viewpoint, the heating temperature is set higher than 50°C.

[0090] This step #6 corresponds to steps (b) and (c). Note that the description of the steps performed after the end of step #6 is omitted because it is common to the first embodiment.

[0091] [Another Embodiment] As described above, the resin plating material 1 includes the base material 3, the microporous layer 5 formed from the surface 3a of the base material 3 over a depth D1 of 20 nm or more, and the electroless plating layer 9 formed on the upper layer of the base material 3, a part of which enters the microporous layer 5 over a depth D2 of 20 nm or more. The present invention targets the resin plating material 1 having such a structure, and its manufacturing method is not limited to the above-described one. For example, in the first embodiment, it is also possible to omit step #2 corresponding to the heating step by increasing the illuminance of the ultraviolet ray L1 in step #3. However, in accurately manufacturing the resin plating material 1, it is preferable to execute step #2 corresponding to the heating step or step #6.

Example

[0092] Hereinafter, specific examples will be shown to explain the present invention in more detail, but the present invention is not limited to the aspects of these examples.

[0093] (Verification 1: Adhesion strength) A plurality of samples with different depths of penetration of the electroless plating layer 9 into the microporous layer 5 were manufactured, and the adhesion strength of each was measured.

[0094] (Example 1) As a sample of the base material 3, a COP resin (manufactured by Nippon Zeon Co., Ltd., 100 μm ZeonorFilm (registered trademark)) defined by the following formula (5) was prepared, and using a light irradiation device (manufactured by USHIO Inc.: SVC 232 Series, peak wavelength 172 nm), the illuminance was 1,200 mJ / cm 2 and the surface of the base material 3 was irradiated with ultraviolet rays for 60 seconds.

[0095] [Chemical formula]

[0096] Thereafter, it was immersed in the conditioner solution M1 to adjust the surface potential of the base material 3 to a cation while performing degreasing treatment. Next, after the water washing treatment, it was immersed in the catalyst-imparting solution M3 to impart a catalyst complex to the surface of the base material 3. Next, after the water washing treatment, the base material 3 was immersed in the activation treatment solution M4 to reduce the catalyst complex to a metal. Next, after the water washing treatment, the base material 3 was immersed in the electroless metal plating solution M5 to reduce metal ions through the catalyst and form an electroless plating layer 9 on the base material 3.

[0097] When the base material 3 was immersed in each chemical solution, it was performed by dipping the base material 3 in a chemical solution pod in which each chemical solution was stored for a predetermined time (several seconds to several minutes) and then taking it out. Also, for the water washing treatment, it was performed by dipping the base material 3 in a washing pod in which washing water (pure water) was stored for a predetermined time (several seconds to several minutes) and then taking it out.

[0098] Each chemical solution used was as follows. · Conditioner liquid M1: PB-102 and EC-B (both manufactured by JCU) · Catalyst-imparting liquid M3: A mixture of AISL-ACT (manufactured by JCU) and hydrochloric acid · Activation treatment liquid M4: A mixture of PC-BA and PB-570B (both manufactured by JCU) · Electroless metal plating liquid M5: A mixture of PC-BA, PB-570MU, PB-570B, and PB-570C (all manufactured by JCU)

[0099] For the sample in which the electroless plating layer 9 was formed on the substrate 3, with reference to FIGS. 5 to 6, the thickness D1 of the microporous layer 5 and the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5 were specified by the method described above.

[0100] Also, stud pins were adhered to the surface of the electroless plating layer 9 and pulled at a constant load rate, and the adhesion strength of the sample was measured by a method conforming to the stud pull peel strength test method (MIL-SID-883). The adhesion strength was 400 [kg / cm 2 or more was evaluated as A, 120 [kg / cm 2 or more and less than 400 [kg / cm 2 was evaluated as B, and less than 120 [kg / cm 2 was determined as C evaluation.

[0101] (Example 2) Samples were prepared in the same manner as in Example 1 except that the illuminance of ultraviolet light was set to 1,800 mJ / cm 2 , and the thickness D1 of the microporous layer 5, the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5, and the adhesion strength were measured respectively.

[0102] (Comparative Example 1) Samples were prepared in the same manner as in Example 1 except that the illuminance of ultraviolet light was set to 500 mJ / cm 2 , and the thickness D1 of the microporous layer 5, the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5, and the adhesion strength were measured respectively.

[0103] (Example 3) Samples were prepared in the same manner as in Example 2, except that the substrate 3 was irradiated with ultraviolet light L1 while being heated to 100°C using a heater, and the thickness D1 of the microporous layer 5, the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5, and the adhesion strength were measured respectively.

[0104] (Examples 4 to 6) Samples were prepared in the same manner as in Example 3, except that the illuminance of the ultraviolet light L1 was varied, and the thickness D1 of the microporous layer 5, the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5, and the adhesion strength were measured respectively.

[0105] (Example 7) As a sample of the substrate 3, a liquid crystal polymer resin defined by the following formula (3) was used. The illuminance of the ultraviolet light was 500 mJ / cm 2 Samples were prepared in the same manner as in Example 1, except that the following chemical solutions were used in each treatment, and the surface potential of the substrate 3 was adjusted to an anion by immersing it in the pre-dip solution M2 before immersing the substrate 3 in the catalyst-imparting solution M3. The thickness D1 of the microporous layer 5, the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5, and the adhesion strength were measured respectively.

[0106] The chemical solutions used were as follows. ·Conditioner solution M1: Top LECS Conditioner (manufactured by Okuno Pharmaceutical Co., Ltd.) ·Pre-dip solution M2: Top LECS Pre-dip M (manufactured by Okuno Pharmaceutical Co., Ltd.) ·Catalyst-imparting solution M3: A mixed solution of Top LECS Catalyst A and Top LECS Catalyst C (both manufactured by Okuno Pharmaceutical Co., Ltd.) ·Activation treatment solution M4: A mixed solution of Top LECS Accelerator (manufactured by Okuno Pharmaceutical Co., Ltd.) and boric acid ·Electroless metal plating solution M5: A mixed solution of Top LECS Copper A, Top LECS Copper M, Top LECS Copper C, and electroless copper R-N (all manufactured by Okuno Pharmaceutical Co., Ltd.)

[0107]

Chemical formula

[0108] (Comparative Example 2) Except that the ultraviolet irradiance was set to 200 mJ / cm 2 Samples were prepared in the same manner as in Example 7 except for the above, and the thickness D1 of the microporous layer 5, the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5, and the adhesion strength were measured respectively.

[0109] (Results) The results are shown in Table 1.

[0110] [Table 1]

[0111] According to Table 1, according to Examples 1 to 7 in which the thickness D2 of the electroless plating layer 9 that penetrated into the microporous layer 5 is 20 nm or more, compared with Comparative Examples 1 to 2 in which the thickness D2 is 5 nm, the adhesion strength between the base material 3 and the electroless plating layer 9 is confirmed to be increased. In particular, according to Examples 3 to 6 in which the thickness D2 is 35 nm or more, it is confirmed that the adhesion strength between the base material 3 and the electroless plating layer 9 is further increased.

[0112] In particular, when comparing Example 2 and Example 3, the adhesion strength of the former was 220 kg / cm 2 whereas the adhesion strength of the latter was 400 kg / cm 2 and the value has increased significantly. This is presumably because not only the magnitude of the thickness D2, but also the heating process was performed when manufacturing the sample of Example 3, improving the strength of the microporous layer 5 itself, and the electroless plating layer 9 penetrated into the microporous layer 5 with improved strength.

[0113] (Verification 2: Effect of introducing oxygen functional groups by heating) When the base material 3 is irradiated with ultraviolet light L1, as described above, a part of the polymer chains constituting the base material 3 is cleaved, and secondarily, substances with low molecular weight are generated. For this reason, it is expected that substances different from the polymer material constituting the base material 3 will be detected by subjecting the base material 3 after irradiation with ultraviolet light L1 to mass spectrometry by the TOF-SIMS method. And when the ultraviolet light L1 reaches only the vicinity of the surface 3a of the base material 3, it is expected that low molecular substances will be detected only in this region.

[0114] Regarding each of the sample of Example 1 irradiated with ultraviolet light L1 without heating and the sample of Example 5 irradiated with ultraviolet light L1 while heating at 100 °C, mass spectrometry was performed by the TOF-SIMS method while sputtering the surface of the base material 3 with an Ar gas cluster ion beam (Ar-GCIB). Both sputtering and mass spectrometry were performed using TOF.SIMS5 manufactured by ION-TOF. In mass spectrometry, normalization was performed using the spectral intensity of C2H5O, which is presumed to be obtained by cleavage of some molecular chains of the COP resin defined by equation (5). The results are shown in FIG. 12.

[0115] According to FIG. 12, compared with Example 1, in Example 5, signals derived from C2H5O are also recognized at extremely deep positions. From this, it is confirmed that by irradiating ultraviolet light L1 while heating, oxygen functional groups are also introduced into regions that have advanced greatly in the depth direction from the surface 3a of the base material 3. This suggests that the thickness D1 of the microporous layer 5 can be increased by irradiating ultraviolet light L1 while heating.

[0116] Further, according to the above verification, it is speculated that not only when ultraviolet light L1 and heating are performed in parallel, but also by the method described above in the first embodiment in which ultraviolet light L1 is irradiated after heating is performed in advance, the thickness D1 of the microporous layer 5 can be increased.

Explanation of reference numerals

[0117] 1: Resin plating material 3: Base material 3a: Surface of the base material 4: Void 5: Microporous layer 7: Catalyst 9: Electroless plating layer 11: Electroplating layer L1: Ultraviolet ray

Claims

1. A base material containing an insulating resin material, A microporous layer formed over a depth of 20 nm or more from the surface of the base material, containing voids on the order of nm and carrying a catalyst, And an electroless plating layer formed on the upper layer of the base material, A resin plating material, characterized in that a part of the electroless plating layer penetrates into the microporous layer located in a region between the surface of the base material and a depth position 20 nm or more from the surface of the base material.

2. The resin plating material according to claim 1, characterized in that the depth range of the region where a part of the electroless plating layer penetrates into the microporous layer is 100 nm or less.

3. The resin plating material according to claim 1 or 2, characterized in that the microporous layer is formed over a depth of 30 nm or more from the surface of the base material.

4. The resin plating material according to claim 1 or 2, characterized in that the microporous layer is formed in a region within a range between the surface of the base material and a depth position 190 nm or less from the surface of the base material.

5. A method for manufacturing the resin plating material according to claim 1, Step (a) of preparing the base material exhibiting thermosetting properties, Step (b) of heating the base material at a temperature higher than 100 °C and lower than the glass transition temperature of the base material, After step (b), irradiating the surface of the base material with ultraviolet light having a main wavelength of 200 nm or less to form voids on the order of nm in the base material over a depth region of 20 nm or more from the surface of the base material, and forming the microporous layer on a part of the base material (step (c)), Step (d) of supporting the catalyst on the surface of the base material and in the region where the microporous layer is formed in the base material, A method for manufacturing a resin plating material, characterized by having step (e) of forming an electroless plating layer from the surface of the base material through the catalyst.

6. The method for manufacturing a resin plating material according to claim 1, comprising: step (a) of preparing the substrate; step (b) of heating the substrate at a temperature higher than 50°C and lower than the glass transition temperature of the substrate; step (c) which is carried out together with step (b), irradiating the surface of the substrate with ultraviolet light having a main wavelength of 200 nm or less to form voids having a size on the order of nm in a depth region of 20 nm or more from the surface of the substrate, and forming the microporous layer on a part of the substrate; step (d) of supporting the catalyst on the surface of the substrate and in the region where the microporous layer is formed in the substrate; step (e) of forming an electroless plating layer from the surface of the substrate through the catalyst, characterized in that it has the method for manufacturing a resin plating material.

7. The method for manufacturing a resin plating material according to claim 5, characterized in that step (a) includes a step of heating the substrate at a lower temperature than step (b).

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