JP2011100778A - Circuit board, and semiconductor device mounted with component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the adhesion of the solder of an electric circuit provided on a surface of a circuit board to a pad area, and to improve the assembling performance of components to the circuit board. <P>SOLUTION: The circuit board 10 has an electric circuit 6 including wiring 6a and a pad 6b on a surface of an insulative base material 1. The electric circuit 6 has a structure in which a conductor 5 is embedded in a circuit recess 3 formed at the surface of the insulative base material 1 where the surface roughness of the conductor 5 differs between the wiring 6a and the pad 6b on the electric circuit 6. In this case, the surface roughness of the conductor 5 of the pad area 6b is preferably larger than that of the conductor 5 of the wiring 6a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention belongs to the technical field of circuit boards and semiconductor devices.

  2. Description of the Related Art Conventionally, as disclosed in, for example, Patent Document 1, a technique for forming an embedded circuit using a CMP (Chemical Mechanical Polishing) process is known in a method for manufacturing a semiconductor integrated circuit device.

  That is, in the circuit forming technique by the CMP process, as illustrated in FIG. 5, a step of forming the wiring groove b on the surface of the insulating base material a (FIG. 5A), and the wiring groove b to fill the wiring groove b Forming a metal member layer c inside and on the surface of the insulating base material a (FIG. 5B), forming the embedded circuit d by removing the metal member layer c outside the wiring groove b by CMP treatment The process (FIG.5 (C)) to perform is included.

JP2009-238896 (paragraph 0015)

  By the way, as shown in FIG. 5D, the circuit d has a wiring part e and a pad part f, and a component x such as a semiconductor chip may be mounted on the pad part f via a solder bump. However, since the surface of the circuit d is polished by the CMP process, both the surface of the wiring part e and the surface of the pad part f are flattened in an extremely smooth state. There is a possibility that a poor connection will occur due to a decrease in adhesion and the reliability of the semiconductor device will be reduced.

  Therefore, the main object of the present invention is to improve the adhesion of solder to the pad portion of an electric circuit provided on the surface of the circuit board, thereby improving the mountability of components on the circuit board. Other objects of the present invention will become apparent later with the configuration and operation of the present invention.

  That is, one aspect of the present invention is a circuit board provided with an electric circuit having a wiring portion and a pad portion on the surface of an insulating base material, and the electric circuit is provided on the surface of the insulating base material. The circuit board has a configuration in which a conductor is embedded in a circuit recess, and the surface roughness of the conductor is different between the wiring portion and the pad portion in the electric circuit.

  According to this configuration, the surface roughness of the conductor in the pad portion is not the same as the surface roughness of the conductor in the wiring portion. On the other hand, in the formation of the embedded circuit by the CMP process, the surface of the insulating substrate and the circuit surface are entirely polished, so that the surface roughness of the conductor in the pad portion and the surface roughness of the conductor in the wiring portion are always the same. And when the surface roughness of the conductor of the pad portion is larger than the surface roughness of the conductor of the wiring portion, the adhesion of the solder when mounting a component such as a semiconductor chip on the pad portion is improved, and The mountability of parts is improved. In the wiring portion, since the surface roughness of the conductor is relatively small, the cross-sectional area of the wiring becomes substantially constant, and the signal transmission speed is stabilized. On the other hand, when the surface roughness of the conductor of the pad portion is smaller than the surface roughness of the conductor of the wiring portion, there are the following advantages. That is, since the area of the pad portion is relatively large, if the surface roughness of the conductor of the pad portion is relatively large, the fluidity of the resin sealing material when packaging is reduced. Therefore, when the surface roughness of the conductor in the pad portion is smaller than the surface roughness of the conductor in the wiring portion, it is possible to suppress a decrease in the fluidity of the resin sealing material and to obtain a good package free from voids.

  The said structure WHEREIN: It is preferable that the surface roughness of the conductor of a pad part is larger than the surface roughness of the conductor of a wiring part. This is because it is possible to achieve both improvement of component mounting on the circuit board and stabilization of the signal transmission speed.

  When the surface roughness of the conductor of the pad portion is larger than the surface roughness of the conductor of the wiring portion, the ten-point average roughness (RzPT) of the surface of the conductor of the pad portion and the ten-point average of the surface of the conductor of the wiring portion The ratio (RzPT / RzLT) to roughness (RzLT) is preferably 2 or more ((RzPT / RzLT) ≧ 2). This is because the effect of improving the adhesiveness of the solder when mounting the component on the pad portion and the effect of stabilizing the signal transmission speed in the wiring portion are surely exhibited. From such a viewpoint, the ratio (RzPT / RzLT) is more preferably 5 or more ((RzPT / RzLT) ≧ 5), and further preferably 10 or more ((RzPT / RzLT) ≧ 10).

  Also, when the surface roughness of the conductor of the pad portion is larger than the surface roughness of the conductor of the wiring portion, the surface of the conductor of the pad portion is linear, curved, latticed, annular, spiral, staggered in plan view And / or it is preferable that the dot-shaped fine recessed part is formed. This is because an effect of improving the solder adhesion in the pad portion can be obtained only by forming a simple shape on the surface of the conductor of the pad portion.

  In that case, a linear, curved, grid, annular, spiral, staggered, and / or dot-shaped fine recess is formed on the bottom surface of the circuit recess of the pad portion in plan view. It is preferable that the fine recess is formed on the surface of the conductor of the pad portion by the conductor following the shape of the bottom surface of the recess. This is because it is no longer necessary to form the fine concave portion on the surface of the conductor of the pad portion, and the process can be shortened. In addition, for example, the conductor can follow the shape of the bottom surface of the circuit recess of the pad portion by depositing the conductor in the circuit recess by electroless plating.

  When the conductor follows the shape of the bottom surface of the circuit recess of the pad portion, the ratio between the ten-point average roughness (RzT) of the surface of the conductor and the ten-point average roughness (RzB) of the bottom surface of the circuit recess. (RzT / RzB) is preferably 0.1 or more and 2.0 or less (0.1 ≦ (RzT / RzB) ≦ 2.0). This is because the shape of the bottom surface of the circuit recess of the pad portion is reliably reflected in the shape of the surface of the conductor of the pad portion, and the fine recess is reliably formed on the surface of the conductor of the pad portion. From such a viewpoint, the ratio (RzT / RzB) is more preferably 0.5 or more and 1.2 or less (0.5 ≦ (RzT / RzB) ≦ 1.2).

  On the other hand, another aspect of the present invention is a circuit board provided with an electric circuit having a wiring part and a pad part on the surface of an insulating base material, and the electric circuit is provided on the surface of the insulating base material. The circuit board is characterized in that a conductor is embedded in the circuit recess, and the surface roughness of the bottom surface of the circuit recess is different between the wiring part and the pad part in the electric circuit.

  According to this configuration, when the surface roughness of the bottom surface of the circuit recess in the pad portion is larger than the surface roughness of the bottom surface of the circuit recess in the wiring portion, the bonding strength of the conductor to the insulating base material is increased in the pad portion. If the surface roughness of the bottom surface of the circuit recess in the wiring portion is greater than the surface roughness of the bottom surface of the circuit recess in the pad portion, the wiring is excellent. In the portion, the bonding strength of the conductor to the insulating base material is excellent, and the dropout of the conductor in the wiring portion from the insulating base material is suppressed.

  The said structure WHEREIN: It is preferable that the surface roughness of the bottom face of the circuit recessed part of a pad part is larger than the surface roughness of the bottom face of the circuit recessed part of a wiring part. This is because the component mounted on the pad portion is also prevented from falling off from the insulating base material.

  In addition, when the surface roughness of the bottom surface of the circuit recess in the pad portion is larger than the surface roughness of the bottom surface of the circuit recess in the wiring portion, the ten-point average roughness (RzPB) of the bottom surface of the circuit recess in the pad portion is The ratio (RzPB / RzLB) to the ten-point average roughness (RzLB) of the bottom surface of the circuit recess of the wiring portion is preferably 2 or more ((RzPB / RzLB) ≧ 2). This is because the action of suppressing the dropout of the conductor of the pad part from the insulating base material and the action of suppressing the dropout of the component mounted on the pad part from the insulating base material are surely exhibited. From such a viewpoint, the ratio (RzPB / RzLB) is more preferably 5 or more ((RzPB / RzLB) ≧ 5), and further preferably 10 or more ((RzPB / RzLB) ≧ 10).

  Also, when the surface roughness of the bottom surface of the circuit recess in the pad portion is larger than the surface roughness of the bottom surface of the circuit recess in the wiring portion, the bottom surface of the circuit recess in the pad portion is linear, curved, It is preferable that fine recesses in a lattice shape, an annular shape, a spiral shape, a staggered shape, and / or a dot shape are formed. The action of suppressing the dropout of the conductor of the pad portion from the insulating base material by simply forming the bottom surface of the circuit recess of the pad portion, and the insulating base material of the component mounted on the pad portion It is because the effect | action which the drop-off from is suppressed is show | played.

  In that case, since the conductor followed the shape of the bottom surface of the circuit recess of the pad portion, the surface of the conductor of the pad portion is linear, curved, latticed, annular, spiral, staggered and / or in plan view. Or it is preferable that the dot-shaped fine recessed part is formed. This is because the adhesiveness of the solder when mounting a component such as a semiconductor chip on the pad portion is improved, and the mountability of the component on the circuit board is improved. Further, it is unnecessary to form the fine recesses on the surface of the conductor of the pad portion, and the process can be shortened. In addition, for example, the conductor can follow the shape of the bottom surface of the circuit recess of the pad portion by depositing the conductor in the circuit recess by electroless plating.

  When the conductor follows the shape of the bottom surface of the circuit recess of the pad portion, the ratio between the ten-point average roughness (RzT) of the surface of the conductor and the ten-point average roughness (RzB) of the bottom surface of the circuit recess. (RzT / RzB) is preferably 0.1 or more and 2.0 or less (0.1 ≦ (RzT / RzB) ≦ 2.0). This is because the shape of the bottom surface of the circuit recess of the pad portion is reliably reflected in the shape of the surface of the conductor of the pad portion, and the fine recess is reliably formed on the surface of the conductor of the pad portion. From such a viewpoint, the ratio (RzT / RzB) is more preferably 0.5 or more and 1.2 or less (0.5 ≦ (RzT / RzB) ≦ 1.2).

  Still another aspect of the present invention is a semiconductor device in which a component is mounted on the pad portion of the circuit board having the above configuration.

  According to the circuit board and the semiconductor device of the present invention, it is possible to improve the adhesion of the solder to the pad portion of the electric circuit provided on the surface of the circuit board, thereby improving the mountability of the components on the circuit board. . Further, it is possible to stabilize the signal transmission speed in the wiring portion. Furthermore, the fluidity | liquidity fall of the resin sealing material at the time of packaging can be suppressed, and the favorable package without a void etc. can be obtained. In addition, it is possible to prevent the conductor of the wiring portion from dropping from the insulating base material, the conductor of the pad portion from dropping from the insulating base material, and the component mounted on the pad portion from dropping from the insulating base material.

(A) The elements on larger scale of the circuit board which concerns on embodiment of this invention, (b) It is sectional drawing which follows the II line. It is process drawing which shows the manufacturing method of the circuit board which concerns on embodiment of this invention. It is a partial expanded sectional view of the semiconductor device by which components were mounted in the pad part of the circuit board based on embodiment of this invention via the solder bump. (A), (b), (c) is the elements on larger scale which show the modification of the pad part of a circuit board, respectively. It is process drawing which shows the formation method of the embedded circuit using the conventional CMP process.

  As shown in FIG. 1, the circuit board 10 according to the present embodiment is a circuit board 10 in which an electric circuit 6 having a wiring part 6 a and a pad part 6 b is provided on the surface of an insulating base 1. The electric circuit 6 has a configuration (embedded circuit) in which the conductor 5 is embedded in the circuit recess 3 provided on the surface of the insulating substrate 1. And the surface roughness of the conductor 5 differs between the wiring part 6a and the pad part 6b in the electric circuit 6.

  In particular, in this embodiment, the surface roughness of the conductor 5 of the pad part 6b is larger than the surface roughness of the conductor 5 of the wiring part 6a. Thereby, in the pad part 6b, since the surface roughness of the conductor 5 is relatively large, the adhesiveness of the solder when the component 20 (see FIG. 3) such as a semiconductor chip is mounted on the pad part 6b is improved. The mountability of the component 20 on the circuit board 10 is improved. In the wiring portion 6a, since the surface roughness of the conductor 5 is relatively small, the cross-sectional area of the wiring becomes almost constant, and the signal transmission speed is stabilized. That is, it is possible to achieve both the improvement of the component mounting property on the circuit board 10 and the stabilization of the signal transmission speed.

  In this embodiment, the ratio (RzPT / RzLT) of the ten-point average roughness (RzPT) of the surface of the conductor 5 of the pad portion 6b to the ten-point average roughness (RzLT) of the surface of the conductor 5 of the wiring portion 6a is 2. This is the above ((RzPT / RzLT) ≧ 2). Thereby, the effect | action which improves the adhesiveness of the solder when mounting the component 20 in the pad part 6b, and the effect | action which the signal transmission speed stabilizes in the wiring part 6a are show | played reliably. From such a viewpoint, the ratio (RzPT / RzLT) is more preferably 5 or more ((RzPT / RzLT) ≧ 5), and further preferably 10 or more ((RzPT / RzLT) ≧ 10).

  If the ratio (RzPT / RzLT) is too small, the effect of improving the adhesiveness of the solder when mounting the component 20 on the pad portion 6b and the effect of stabilizing the signal transmission speed in the wiring portion 6a are insufficient. If the ratio (RzPT / RzLT) is too large, a large amount of solder is required when the component 20 is mounted on the pad portion 6b, which makes fine processing difficult.

  In the present embodiment, linear fine concave portions are formed on the surface of the conductor 5 of the pad portion 6b in a plan view. Then, the surface roughness of the conductor 5 of the pad portion 6b is made larger than the surface roughness of the conductor 5 of the wiring portion 6a by this linear fine recess. Thereby, only by forming a simple shape on the surface of the conductor 5 of the pad portion 6b, an effect of improving the solder adhesion in the pad portion 6b is exhibited.

  In the present embodiment, among the circuit recesses 3, linear fine recesses in a plan view are formed on the bottom surface of the circuit recess 3b (see FIG. 2B) of the pad portion 6b. And since the conductor 5 followed the shape of the linear fine recessed part of this bottom face, the said fine recessed part is formed in the surface of the conductor 5 of the pad part 6b. Thereby, it is not necessary to bother to form the fine recesses on the surface of the conductor 5 of the pad portion 6b, and the process can be shortened.

  In this embodiment, the ratio (RzT / RzB) of the ten-point average roughness (RzT) of the surface of the conductor 5 to the ten-point average roughness (RzB) of the bottom surface of the circuit recess 3 is 0.1 or more and 2. 0 or less (0.1 ≦ (RzT / RzB) ≦ 2.0). Thereby, the shape of the bottom surface of the circuit recess 3b of the pad portion 6b is reliably reflected in the shape of the surface of the conductor 5 of the pad portion 6b, and the fine recess is reliably formed on the surface of the conductor 5 of the pad portion 6b. The From such a viewpoint, the ratio (RzT / RzB) is more preferably 0.5 or more and 1.2 or less (0.5 ≦ (RzT / RzB) ≦ 1.2).

  If the ratio (RzT / RzB) is too small, the shape of the bottom surface of the circuit recess 3b of the pad portion 6b is reflected in the shape of the surface of the conductor 5 of the pad portion 6b, and the surface of the conductor 5 of the pad portion 6b becomes fine. The effect of forming the recess is insufficient. If the ratio (RzT / RzB) is too large, the wiring portion 6a has an insufficient effect of stabilizing the signal transmission speed. In the pad portion 6b, the solder is not formed when the component 20 is mounted on the pad portion 6b. A large amount is required, and fine processing becomes difficult.

  Similarly, as shown in FIG. 1, the circuit board 10 according to the present embodiment is a circuit board 10 in which an electric circuit 6 having a wiring part 6 a and a pad part 6 b is provided on the surface of the insulating base 1. . The electric circuit 6 has a configuration (embedded circuit) in which the conductor 5 is embedded in the circuit recess 3 provided on the surface of the insulating substrate 1. And the surface roughness of the bottom face of the circuit recess 3 is different between the wiring part 6 a and the pad part 6 b in the electric circuit 6.

  In particular, in this embodiment, the surface roughness of the bottom surface of the circuit recess 3b (see FIG. 2B) of the pad portion 6b is the surface of the bottom surface of the circuit recess 3a (see FIG. 2B) of the wiring portion 6a. It is larger than the roughness. Thereby, in the pad part 6b, it is excellent in the joining strength of the conductor 5 to the insulating base material 1, and the drop-off | omission from the insulating base material 1 of the conductor 5 of the pad part 6b is suppressed. Moreover, dropping off of the component 20 (see FIG. 3) such as a semiconductor chip mounted on the pad portion 6b from the insulating base 1 is also suppressed.

  In the present embodiment, the ratio (RzPB / R) of the ten-point average roughness (RzPB) of the bottom surface of the circuit recess 3b of the pad portion 6b and the ten-point average roughness (RzLB) of the bottom surface of the circuit recess 3a of the wiring portion 6a. RzLB) is set to 2 or more ((RzPB / RzLB) ≧ 2). Thereby, the effect | action which the drop-off from the insulating base material 1 of the conductor 5 of the pad part 6b is suppressed, and the effect | action which the drop-off | omission from the insulation base material 1 of the components 20 mounted in the pad part 6b are suppressed reliably. Because it is played. From such a viewpoint, the ratio (RzPB / RzLB) is more preferably 5 or more ((RzPB / RzLB) ≧ 5), and further preferably 10 or more ((RzPB / RzLB) ≧ 10).

  If the ratio (RzPB / RzLB) is too small, the action of suppressing the drop-off of the conductor 5 of the pad portion 6b from the insulating base material 1 and the component 20 mounted on the pad portion 6b from the insulating base material 1 are suppressed. Insufficient drop-off action. If the ratio (RzPB / RzLB) is too large, the circuit recess 3b of the pad portion 6b must be dug deeper than necessary, resulting in useless processing.

  In the present embodiment, linear fine recesses in a plan view are formed on the bottom surface of the circuit recess 3b of the pad portion 6b. Then, the surface roughness of the bottom surface of the circuit recess 3b of the pad portion 6b is made larger than the surface roughness of the bottom surface of the circuit recess 3a of the wiring portion 6a. Thus, by simply forming a simple shape on the bottom surface of the circuit recess 3b of the pad portion 6b, the pad portion 6b can be prevented from falling off the conductor 5 from the insulating base 1, and mounted on the pad portion 6b. The effect | action which the drop-off | omission from the insulating base material 1 of the performed component 20 is suppressed is show | played.

  In the present embodiment, the conductor 5 follows the shape of the bottom surface of the circuit recess 3b of the pad portion 6b, so that a linear fine recess is formed on the surface of the conductor 5 of the pad portion 6b in a plan view. Thereby, the adhesiveness of the solder when the component 20 is mounted on the pad portion 6b is improved, and the mountability of the component 20 on the circuit board 1 is improved. Further, it is not necessary to form the fine recesses on the surface of the conductor 5 of the pad portion 6b, and the process can be shortened.

  In this embodiment, the ratio (RzT / RzB) of the ten-point average roughness (RzT) of the surface of the conductor 5 to the ten-point average roughness (RzB) of the bottom surface of the circuit recess 3 is 0.1 or more and 2. 0 or less (0.1 ≦ (RzT / RzB) ≦ 2.0). Thereby, the shape of the bottom surface of the circuit recess 3b of the pad portion 6b is reliably reflected in the shape of the surface of the conductor 5 of the pad portion 6b, and the fine recess is reliably formed on the surface of the conductor 5 of the pad portion 6b. The From such a viewpoint, the ratio (RzT / RzB) is more preferably 0.5 or more and 1.2 or less (0.5 ≦ (RzT / RzB) ≦ 1.2).

  If the ratio (RzT / RzB) is too small, the shape of the bottom surface of the circuit recess 3b of the pad portion 6b is reflected in the shape of the surface of the conductor 5 of the pad portion 6b, and the surface of the conductor 5 of the pad portion 6b becomes fine. The effect of forming the recess is insufficient. If the ratio (RzT / RzB) is too large, the wiring portion 6a has an insufficient effect of stabilizing the signal transmission speed. In the pad portion 6b, the solder is not formed when the component 20 is mounted on the pad portion 6b. A large amount is required, and fine processing becomes difficult.

  Hereinafter, the present invention will be described in more detail by describing a method for manufacturing the circuit board 10 according to the present embodiment.

  FIG. 2 is a process diagram showing a method for manufacturing the circuit board 10 according to the present embodiment. In FIG. 2, reference numeral 1 is an insulating substrate, reference numeral 2 is a resin film, reference numeral 3 is a circuit recess as a circuit pattern, reference numeral 3a is a circuit recess in the wiring part, reference numeral 3b is a circuit recess in the pad part, reference numeral 4 Is a plating catalyst, 5 is electroless plating as a conductor, 6 is an electric circuit, 6a is a wiring portion, and 6b is a pad portion.

<Resin film formation process>
First, as shown in FIG. 2A, a resin film 2 is formed on the surface of the insulating substrate 1.

  As the insulating substrate 1, various organic substrates conventionally used for manufacturing circuit boards can be used without any particular limitation. Specific examples of the organic substrate include substrates made of epoxy resin, acrylic resin, polycarbonate resin, polyimide resin, polyphenylene sulfide resin, polyphenylene ether resin, cyanate resin, benzoxazine resin, bismaleimide resin, and the like.

  The epoxy resin is not particularly limited as long as it is an epoxy resin constituting various organic substrates that can be used for manufacturing a circuit board. Specifically, for example, bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol S type epoxy resin, aralkyl epoxy resin, phenol novolac type epoxy resin, alkylphenol novolac type epoxy resin, biphenol type epoxy resin, naphthalene type epoxy resin , Dicyclopentadiene type epoxy resins, epoxidized products of condensates of phenols and aromatic aldehydes having a phenolic hydroxyl group, triglycidyl isocyanurate, alicyclic epoxy resins, and the like. Furthermore, the epoxy resin, nitrogen-containing resin, silicone-containing resin, and the like that are brominated or phosphorus-modified to impart flame retardancy are also included. Moreover, as said epoxy resin and resin, each said epoxy resin and resin may be used independently, and may be used in combination of 2 or more type.

  When the substrate is composed of each resin, generally, a curing agent is contained for curing. The curing agent is not particularly limited as long as it can be used as a curing agent. Specific examples include dicyandiamide, phenolic curing agents, acid anhydride curing agents, aminotriazine novolac curing agents, and cyanate resins.

  As said phenol type hardening | curing agent, a novolak type, an aralkyl type, a terpene type etc. are mentioned, for example. Furthermore, phosphorus-modified phenolic resins or phosphorus-modified cyanate resins for imparting flame retardancy are also included. Moreover, as said hardening | curing agent, each said hardening | curing agent may be used independently, and may be used in combination of 2 or more type.

  As will be described later, since a circuit recess 3 as a circuit pattern is formed on the surface of the insulating substrate 1 by laser processing in the circuit pattern forming step, laser light in a wavelength region of 100 nm to 400 nm is formed. It is preferable to use a resin having a good absorption rate (UV absorption rate). For example, specifically, a polyimide resin or the like can be given.

  You may make the insulating base material 1 contain a filler. The filler may be inorganic fine particles or organic fine particles, and is not particularly limited. By containing a filler, a filler is exposed to a laser processing part and the adhesiveness of plating (conductor 5) and resin (insulating base material 1) by the unevenness | corrugation of a filler can be improved.

Specific examples of the material constituting the inorganic fine particles include aluminum oxide (Al ₂ O ₃ ), magnesium oxide (MgO), boron nitride (BN), aluminum nitride (AlN), silica (SiO ₂ ), and titanium. High dielectric constant filler such as barium oxide (BaTiO ₃ ) and titanium oxide (TiO ₂ ); magnetic filler such as hard ferrite; magnesium hydroxide (Mg (OH) ₂ ), aluminum hydroxide (Al (OH) ₂ ) Inorganic flame retardants such as antimony trioxide (Sb ₂ O ₃ ), antimony pentoxide (Sb ₂ O ₅ ), guanidine salt, zinc borate, molybdate compound, zinc stannate; talc (Mg ₃ (Si ₄ O ₁₀ ) (OH) ₂ ), barium sulfate (BaSO ₄ ), calcium carbonate (CaCO ₃ ), mica and the like. As the inorganic fine particles, the inorganic fine particles may be used alone or in combination of two or more. These inorganic fine particles have high thermal conductivity, relative dielectric constant, flame retardancy, particle size distribution, color tone flexibility, etc. And high filling can be easily performed. Although not particularly limited, it is preferable to use a filler having an average particle diameter equal to or less than the thickness of the insulating layer, more preferably 0.01 μm to 10 μm, and still more preferably a filler having an average particle diameter of 0.05 μm to 5 μm. It is good.

  The inorganic fine particles may be surface-treated with a silane coupling agent in order to improve dispersibility in the insulating base material 1. In addition, the insulating substrate 1 may contain a silane coupling agent in order to increase the dispersibility of the inorganic fine particles in the insulating substrate 1. The silane coupling agent is not particularly limited. Specific examples include silane coupling agents such as epoxy silane, mercapto silane, amino silane, vinyl silane, styryl silane, methacryloxy silane, acryloxy silane, and titanate. As said silane coupling agent, the said silane coupling agent may be used independently, and may be used in combination of 2 or more type.

  The insulating substrate 1 may contain a dispersant in order to improve the dispersibility of the inorganic fine particles in the insulating substrate 1. The dispersant is not particularly limited. Specific examples include dispersants such as alkyl ether, sorbitan ester, alkyl polyether amine, and polymer. As said dispersing agent, the said dispersing agent may be used independently and may be used in combination of 2 or more type.

  Specific examples of the organic fine particles that can be used as the filler include rubber fine particles.

  The form of the insulating substrate 1 is not particularly limited. Specific examples include a sheet, a film, a prepreg, and a three-dimensional shaped molded body. The thickness of the insulating substrate 1 is not particularly limited. For example, in the case of a sheet, a film, a prepreg, etc., for example, 10 to 500 μm, preferably 10 to 200 μm, more preferably 20 to 200 μm, and still more preferably about 20 to 100 μm. Of the thickness.

  Moreover, the insulating base material 1 may be formed into a three-dimensional shaped molded body or the like by, for example, putting a material to be an insulating base material using a mold and a frame mold, pressurizing and curing the material. Then, the sheet, film, or prepreg may be punched out and cured, or cured by heat and pressure, to form a three-dimensional shaped molded body or the like.

  Next, the resin film (resist) 2 is not particularly limited as long as it can be removed by a film removal step described later. The resin film 2 is preferably a resin film that can be easily dissolved or removed from the surface of the insulating substrate 1 by dissolving or swelling with a predetermined liquid. Specifically, for example, a film made of a soluble resin that can be easily dissolved by an organic solvent or an alkaline solution, a film made of a swellable resin that can swell with a predetermined liquid (swelling liquid), and the like can be given. Note that the swellable resin film does not substantially dissolve in a predetermined liquid, and is not only a resin film that easily peels off from the surface of the insulating substrate 1 by swelling, but also swells in a predetermined liquid. Furthermore, at least a part of the resin film is dissolved and easily dissolved from the surface of the insulating base material 1 by swelling or dissolution, or dissolved in a predetermined liquid, and the surface of the insulating base material 1 is dissolved by the dissolution. Also included is a resin film that easily peels off. By using such a resin film, the resin film 2 can be easily and satisfactorily removed from the surface of the insulating substrate 1. When the resin film 2 is disintegrated when the resin film 2 is removed, the plating catalyst 4 deposited on the resin film 2 scatters, and the scattered plating catalyst is re-deposited on the insulating substrate 1 and is unnecessary in that portion. There is a problem that plating is formed. In this embodiment, since the resin film 2 can be easily and satisfactorily removed from the surface of the insulating substrate 1, such a problem can be prevented.

  The method for forming the resin film 2 is not particularly limited. Specifically, for example, it is formed by applying a liquid material capable of forming the resin film 2 on the surface of the insulating substrate 1 and then drying, or by applying the liquid material to a support substrate and then drying it. And a method of transferring the resin film to be transferred onto the surface of the insulating substrate 1. Moreover, as another method, the method of bonding the resin film which consists of the resin film 2 formed in advance on the surface of the insulating base material 1 etc. are mentioned. The method for applying the liquid material is not particularly limited. Specifically, for example, conventionally known spin coating method, bar coater method and the like can be mentioned.

  As a material for forming the resin film 2, any resin can be used without particular limitation as long as it can be easily dissolved or removed from the surface of the insulating substrate 1 by dissolving or swelling with a predetermined liquid. Preferably, a resin having a degree of swelling with respect to a predetermined liquid is 50% or more, more preferably 100% or more, and still more preferably 500% or more. In addition, when the degree of swelling is too low, the resin film tends to be difficult to peel.

  In addition, the swelling degree (SW) of the resin film can be calculated from the weight m (b) before swelling and the weight m (a) after swelling by “swelling degree SW = {(m (a) −m (b)) / m (b )} × 100 (%) ”.

  Such a resin film 2 is formed by applying an elastomer suspension or emulsion to the surface of the insulating substrate 1 and then drying, or by applying an elastomer suspension or emulsion to the support substrate and then drying. The film can be easily formed by a method of transferring the film to be transferred onto the surface of the insulating substrate 1.

  Specific examples of the elastomer include diene elastomers such as a styrene-butadiene copolymer, acrylic elastomers such as an acrylate ester copolymer, and polyester elastomers. According to such an elastomer, a resin film having a desired swelling degree can be easily formed by adjusting the degree of crosslinking or gelation of the elastomer resin particles dispersed as a suspension or emulsion.

  The resin film 2 is particularly preferably a film whose degree of swelling changes depending on the pH of the swelling liquid. In the case of using such a film, the liquid condition in the catalyst deposition process described later is different from the liquid condition in the film removal process described later, so that the resin is used at the pH in the catalyst deposition process. The film 2 can easily peel and remove the resin film 2 from the insulating substrate 1 at the pH in the film removing step while maintaining high adhesion to the insulating substrate 1.

  More specifically, for example, the catalyst deposition step described later includes a step of treating in an acidic catalyst metal colloid solution having a pH in the range of 1 to 3, for example, and the film removal step described below has a pH of 12 to 14, for example. When the resin film 2 is provided with a step of swelling the resin film in an alkaline solution in the range, the resin film 2 has a swelling degree with respect to the acidic catalyst metal colloid solution of 60% or less, more preferably 40% or less. It is preferable that the resin film has a swelling degree with respect to the solution of 50% or more, more preferably 100% or more, and still more preferably 500% or more.

  Examples of such a resin film 2 are used for a sheet formed from an elastomer having a predetermined amount of carboxyl groups, a dry film resist for patterning a printed wiring board (hereinafter sometimes referred to as “DFR”), and the like. Examples thereof include a sheet obtained by completely curing a photocurable alkali-developable resist, a thermosetting or alkali-developable sheet, and the like.

  Specific examples of the elastomer having a carboxyl group include diene elastomers such as a styrene-butadiene copolymer having a carboxyl group in the molecule by containing a monomer unit having a carboxyl group as a copolymerization component, and acrylic. Examples include acrylic elastomers such as acid ester copolymers, and polyester elastomers. According to such an elastomer, a resin film having a desired degree of alkali swelling can be formed by adjusting the acid equivalent, the degree of crosslinking or the degree of gelation of the elastomer dispersed as a suspension or emulsion. Moreover, the swelling degree with respect to the predetermined liquid used in a film removal process can be increased, and a resin film that dissolves in the liquid can be easily formed. The carboxyl group in the elastomer swells the resin film with respect to the alkaline aqueous solution, and acts to peel the resin film 2 from the surface of the insulating substrate 1. The acid equivalent is the polymer molecular weight per carboxyl group.

  Specific examples of the monomer unit having a carboxyl group include (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, and the like.

  As a content rate of the carboxyl group in the elastomer which has such a carboxyl group, it is preferable that it is 100-2000 by an acid equivalent, Preferably it is 100-800. When the acid equivalent is too small (when the number of carboxyl groups is relatively large), the compatibility with a pretreatment solution for electroless plating is reduced due to a decrease in compatibility with a solvent or other composition. Tend. In addition, when the acid equivalent is too large (when the number of carboxyl groups is relatively small), the peelability with respect to the alkaline aqueous solution tends to decrease.

  The molecular weight of the elastomer is 10,000 to 1,000,000, preferably 20,000 to 500,000, and more preferably 20,000 to 60,000. When the molecular weight of the elastomer is too large, the peelability tends to decrease. When the molecular weight is too small, the viscosity decreases and it becomes difficult to maintain a uniform thickness of the resin film. There is also a tendency that the resistance to the treatment liquid also decreases.

  In addition, as DFR, for example, an acrylic resin, an epoxy resin, a styrene resin, a phenol resin, a urethane resin, or the like containing a predetermined amount of a carboxyl group is used as a resin component, and a photopolymerization initiator is included. A sheet of curable resin composition may be used. Specific examples of such DFR include a dry film of a photopolymerizable resin composition as disclosed in JP-A-2000-231190, JP-A-2001-201851, and JP-A-11-212262. Sheets obtained by curing, and commercially available as an alkali development type DFR, for example, UFG series manufactured by Asahi Kasei Kogyo Co., Ltd. may be mentioned.

  Further, other examples of the resin film 2 include a rosin-based resin (for example, “NAZDAR229” manufactured by Yoshikawa Chemical Co., Ltd.) containing a carboxyl group, and a phenol-based resin (for example, LEKTRACHEM). "104F" manufactured by the company).

  The resin film 2 is formed by applying a resin suspension or emulsion on the surface of the insulating substrate 1 using a conventionally known application method such as a spin coat method or a bar coater method, and then drying or After the formed DFR is bonded to the surface of the insulating substrate 1 using a vacuum laminator or the like, it can be easily formed by curing the entire surface.

  For example, the thickness of the resin film 2 is preferably 10 μm or less, and more preferably 5 μm or less. Moreover, 0.1 micrometer or more is preferable and 1 micrometer or more is further more preferable. If the thickness is too thick, the accuracy tends to decrease when a fine circuit pattern (circuit recess 3) is formed by laser processing, machining, or the like. Moreover, when thickness is too thin, there exists a tendency for it to become difficult to form the resin film 2 of uniform film thickness.

  Moreover, as the resin film 2, for example, a resin film mainly composed of a resin (carboxyl group-containing acrylic resin) made of an acrylic resin having a carboxyl group with an acid equivalent of about 100 to 800 can also be used. .

  In addition to the above, the following is also suitable as the resin film 2. That is, the necessary characteristics of the resist material constituting the resin film 2 include, for example, (1) a liquid (plating nucleation) in which the insulating base material 1 on which the resin film 2 is formed is immersed in a catalyst deposition step described later. (2) The resin film (resist) 2 can be easily removed by the film removal step described later, for example, the step of immersing the insulating base material 1 on which the resin film 2 is formed in alkali, (3) High film formability, (4) Easy dry film (DFR) formation, (5) High storage stability, and the like. As the plating nucleation chemical solution, as will be described later, for example, in the case of an acidic Pd—Sn colloid catalyst system, all are acidic (for example, pH 1 to 3) aqueous solutions. Moreover, in the case of an alkaline Pd ion catalyst system, the catalyst imparting activator is a weak alkali (pH 8 to 12), and the others are acidic. From the above, it is necessary to withstand pH 1 to 11, and preferably pH 1 to 12, as the resistance to the plating nucleating solution. In addition, being able to withstand is that when a sample on which a resist is formed is immersed in a chemical solution, swelling and dissolution of the resist are sufficiently suppressed, and the resist plays a role as a resist. The immersion temperature is generally room temperature to 60 ° C., the immersion time is 1 to 10 minutes, and the resist film thickness is generally about 1 to 10 μm, but is not limited thereto. As described later, the alkali stripping chemical used in the film removal step is generally an aqueous NaOH solution or an aqueous sodium carbonate solution. Its pH is 11 to 14, and it is desirable that the resist film can be easily removed preferably at pH 12 to 14. The NaOH aqueous solution concentration is generally about 1 to 10%, the processing temperature is room temperature to 50 ° C., the processing time is 1 to 10 minutes, and the immersion or spray treatment is generally performed, but is not limited thereto. Since a resist is formed on an insulating material, film formability is also important. A uniform film formation without repelling or the like is necessary. Moreover, although it is made into a dry film for the simplification of a manufacturing process, reduction of material loss, etc., the flexibility of a film is required in order to ensure handling property. Also, a dry film resist is pasted on the insulating material with a laminator (roll, vacuum). The pasting temperature is room temperature to 160 ° C., and the pressure and time are arbitrary. Thus, adhesiveness is required at the time of pasting. For this reason, the resist formed into a dry film is generally used as a three-layer structure sandwiched by a carrier film and a cover film to prevent dust from adhering, but is not limited thereto. The storability is preferably storable at room temperature, but it is also necessary to be able to be refrigerated or frozen. As described above, it is necessary to prevent the composition of the dry film from being separated at low temperatures or to be cracked due to a decrease in flexibility.

  From the above viewpoint, as the resin film 2, (a) at least one monomer of carboxylic acid or acid anhydride having at least one polymerizable unsaturated group in the molecule, and (b) ( It may be a polymer resin obtained by polymerizing a) at least one monomer that can be polymerized with a monomer, or a resin composition containing this polymer resin. Known techniques include JP-A-7-281437, JP-A-2000-231190, JP-A-2001-201851, and the like. Examples of (a) monomers include (meth) acrylic acid, fumaric acid, cinnamic acid, crotonic acid, itaconic acid, maleic anhydride, maleic acid half ester, butyl acrylate, and the like. Or you may combine two or more types. Examples of the monomer (b) are generally non-acidic and have (1) a polymerizable unsaturated group in the molecule, but are not limited thereto. It is selected so as to maintain various characteristics such as resistance in a catalyst deposition step described later and flexibility of the cured film. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2 -There are hydroxylethyl (meth) acrylates and 2-hydroxylpropyl (meth) acrylates. Further, there are esters of vinyl alcohol such as vinyl acetate, (meth) acrylonitrile, styrene or polymerizable styrene derivatives. It can also be obtained by polymerization of only a carboxylic acid or acid anhydride having one polymerizable unsaturated group in the molecule. Furthermore, a monomer having a plurality of unsaturated groups can be selected as the monomer used for the polymer so that three-dimensional crosslinking can be performed. In addition, reactive functional groups such as epoxy groups, hydroxyl groups, amino groups, amide groups, and vinyl groups can be introduced into the molecular skeleton.

  When a carboxyl group is contained in the resin, the amount of the carboxyl group contained in the resin is preferably 100 to 2000, preferably 100 to 800, as an acid equivalent. If the acid equivalent is too low, the compatibility with the solvent or other composition is lowered and the resistance to the plating pretreatment solution is lowered. If the acid equivalent is too high, the peelability is lowered. Further, the composition ratio of the monomer (a) is preferably 5 to 70% by mass.

  The resin composition may contain the polymer resin as an essential component as a main resin (binder resin), and may contain at least one of oligomers, monomers, fillers, and other additives. The main resin is preferably a linear polymer having thermoplastic properties. In order to control fluidity and crystallinity, it may be branched by grafting. The molecular weight is about 1,000 to 500,000 in terms of weight average molecular weight, and preferably 5,000 to 50,000. When the weight average molecular weight is small, the flexibility of the film and the resistance to the plating nucleation solution (acid resistance) are lowered. On the other hand, when the molecular weight is large, the alkali peelability and the sticking property when a dry film is formed deteriorate. Furthermore, a crosslinking point may be introduced to improve resistance to plating nucleus chemicals, suppress thermal deformation during laser processing, and control flow.

  Any monomer or oligomer may be used as long as it is resistant to plating nucleation chemicals and can be easily removed with alkali. Further, in order to improve the sticking property of the dry film (DFR), it can be considered that it is used as a tackifier as a plasticizer. Further, it is conceivable to add a crosslinking agent in order to increase various resistances. Specifically, methyl (meth) acrylate, ethyl (meth) acrylate, iso-propyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, tert-butyl (meth) acrylate, 2 -There are hydroxylethyl (meth) acrylates and 2-hydroxylpropyl (meth) acrylates. Further, there are esters of vinyl alcohol such as vinyl acetate, (meth) acrylonitrile, styrene or polymerizable styrene derivatives. It can also be obtained by polymerization of only a carboxylic acid or acid anhydride having one polymerizable unsaturated group in the molecule. Furthermore, a polyfunctional unsaturated compound may be included. Any of the above monomers or oligomers obtained by reacting the monomers may be used. In addition to the above monomers, it is possible to include two or more other photopolymerizable monomers. Examples of monomers include 1,6-hexanediol di (meth) acrylate, 1,4-cyclohexanediol di (meth) acrylate, polypropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polyoxyethylene Polyoxyalkylene glycol di (meth) acrylate such as polyoxypropylene glycol di (meth) acrylate, 2-di (p-hydroxyphenyl) propane di (meth) acrylate, glycerol tri (meth) acrylate, dipentaerythritol penta (meth) Acrylate, trimethylolpropane triglycidyl ether tri (meth) acrylate, bisphenol A diglycidyl ether tri (meth) acrylate, 2,2-bis (4-methacryloxy) Pointer ethoxyphenyl) propane, there is a polyfunctional (meth) acrylate containing urethane groups. Any of the above monomers or oligomers obtained by reacting the monomers may be used.

  The filler is not particularly limited, but silica, aluminum hydroxide, magnesium hydroxide, calcium carbonate, clay, kaolin, titanium oxide, barium sulfate, alumina, zinc oxide, talc, mica, glass, potassium titanate, wollastonite, sulfuric acid Magnesium, aluminum borate, an organic filler, etc. are mentioned. Moreover, since the preferable thickness of a resist is as thin as 0.1-10 micrometers, the thing with a small filler size is preferable. Although it is preferable to use a material having a small average particle size and cut coarse particles, the coarse particles can be crushed during dispersion or removed by filtration.

  Examples of other additives include a photopolymerizable resin (photopolymerization initiator), a polymerization inhibitor, a colorant (dye, pigment, coloring pigment), a thermal polymerization initiator, and a crosslinking agent such as epoxy and urethane.

  In the circuit pattern forming process to be described next, the resin film 2 is subjected to laser processing or the like, and therefore it is necessary to impart a laser ablation property to the resist material. As the laser processing machine, for example, a carbon dioxide laser, an excimer laser, a UV-YAG laser, or the like is selected. These laser processing machines have various intrinsic wavelengths, and productivity can be improved by selecting a material having a high UV absorption rate for these wavelengths. Among them, the UV-YAG laser is suitable for fine processing, and the laser wavelength is 3rd harmonic 355 nm and 4th harmonic 266 nm. Therefore, it is desirable that the UV absorption rate is relatively high. The higher the UV absorption, the better the processing of the resist (resin film 2), and the productivity can be improved. However, the present invention is not limited to this, and it may be better to select a resist material having a relatively low UV absorption rate. The lower the UV absorption rate, the more UV light passes through the resist (resin film 2), so that the UV energy can be concentrated in the processing of the underlying insulating substrate 1, for example, the insulating substrate 1 is difficult to process. Particularly favorable results are obtained when Thus, it is preferable to design a resist material according to the ease of laser processing of the resist (resin film 2), the ease of laser processing of the insulating substrate 1, and their relationship.

<Circuit pattern formation process>
Next, as shown in FIG. 2B, a groove 3a and a hole 3b having a predetermined depth and a predetermined shape that are equal to or greater than the thickness of the resin film 2 are formed from the outer surface side of the resin film 2 as a circuit pattern. A circuit recess 3 is formed on the surface of the insulating substrate 1. The circuit recess 3 can be formed by machining such as cutting or embossing, but a preferable result can be obtained when formed by laser processing. Further, the groove 3a of the circuit recess 3 is a circuit recess of the wiring portion 6a, and the hole 3b of the circuit recess 3 is a circuit recess of the pad portion 6b. Further, depending on the situation, the circuit recess 3 may include an interlayer connection via.

  The width of the circuit recess 3a of the wiring portion 6a in the circuit recess 3 is not particularly limited. However, when laser processing is used, a fine groove having a line width of 20 μm or less can be easily formed. The vertical and horizontal lengths of the circuit recess 3b of the pad 6b in the circuit recess 3 are not particularly limited. Although FIG. 1 shows a case where the pad portion 6b has a quadrangular shape in plan view, the shape is not limited to this, and other shapes may be used.

  The method for forming the circuit recess 3 is not particularly limited. Specifically, cutting by laser processing, dicing processing, etc., embossing, etc. are used. Laser processing is preferable for forming the fine circuit recesses 3 with high accuracy. According to laser processing, by controlling the output (energy or power) of the laser, it is possible to easily adjust the digging depth of the insulating base material 1 through the resin film 2. As the embossing, for example, embossing with a fine resin mold used in the field of nanoimprinting can be preferably used.

  By forming the predetermined circuit recess 3 in this manner, a portion where an electroless plating film is provided later to form the electric circuit 6 is defined.

  When the circuit recess 3 is formed by laser processing, the circuit recess 3a of the wiring portion 6a can form a single groove if the laser light is run only once along the circuit pattern. However, as apparent from FIG. 1 (a), the pad portion 6b is wider and larger in area than the wiring portion 6a, so that the circuit recess 3b of the pad portion 6b is formed by running the laser light multiple times. be able to. In the present embodiment, as is apparent from FIGS. 1 and 2, the quadrangular pad portion 6b is formed in plan view by causing the laser light to run in a straight line a plurality of times in parallel. As a result, a plurality of linear fine recesses in a plan view are formed on the bottom surface of the circuit recess 3b of the pad portion 6b as traces of running laser light. As a result, a plurality of irregularities are formed on the bottom surface of the circuit recess 3b of the pad portion 6b. Then, the surface roughness of the bottom surface of the circuit recess 3a of the wiring portion 6a is such that the surface roughness of the bottom of the circuit recess 3b of the pad portion 6b is reduced by the fine recesses (a plurality of recesses and projections) on the bottom of the circuit recess 3b of the pad portion 6b. It is larger than the roughness. That is, in the wiring part 6a, since the laser beam is only run once along the circuit pattern, the bottom surface of the circuit recess 3a of the wiring part 6a is not uneven. In that case, the ratio (RzPB / RzLB) of the ten-point average roughness (RzPB) of the bottom surface of the circuit recess 3b of the pad portion 6b and the ten-point average roughness (RzLB) of the bottom surface of the circuit recess 3a of the wiring portion 6a. ) Is preferably 2 or more ((RzPB / RzLB) ≧ 2), preferably 5 or more ((RzPB / RzLB) ≧ 5), more preferably 10 or more ((RzPB / RzLB) ≧ 10). Street.

  In a subsequent plating step, the circuit recess 6 is filled with the electroless plating conductor 5 to form the circuit 6, so that the electroless plating plating film grows from the bottom surface of the circuit recess 3. As a result, the surface shape of the conductor 5 follows the shape of the bottom surface of the circuit recess 3. Therefore, the surface shape of the conductor 5 of the pad portion 6b reflects and follows the shape of the bottom surface of the circuit recess 3b of the pad portion 6b. As a result, a plurality of linear concave portions that are linear in a plan view are formed on the surface of the conductor 5 of the pad portion 6b. As a result, a plurality of irregularities are formed on the surface of the conductor 5 of the pad portion 6b. And the surface roughness of the conductor 5 of the pad part 6b is larger than the surface roughness of the conductor 5 of the wiring part 6a by the fine recessed part (several unevenness | corrugations) of the surface of the conductor 5 of this pad part 6b. That is, in the wiring portion 6a, since the bottom surface of the circuit recess 3a is not uneven, the surface of the conductor 5 of the wiring portion 6a cannot be uneven. In this case, the ratio (RzPT / RzLT) of the ten-point average roughness (RzPT) of the surface of the conductor 5 of the pad portion 6b to the ten-point average roughness (RzLT) of the surface of the conductor 5 of the wiring portion 6a is 2 As described above, ((RzPT / RzLT) ≧ 2) is preferable, 5 or more ((RzPT / RzLT) ≧ 5) is more preferable, and 10 or more ((RzPT / RzLT) ≧ 10) is further preferable. Furthermore, when the conductor 5 follows the shape of the bottom surface of the circuit recess 3, the ten-point average roughness (RzT) of the surface of the conductor 5 and the ten-point average roughness (RzB) of the bottom surface of the circuit recess 3 The ratio (RzT / RzB) is preferably 0.1 or more and 2.0 or less (0.1 ≦ (RzT / RzB) ≦ 2.0), and is 0.5 or more and 1.2 or less (0.5 ≦ ( As described above, RzT / RzB) ≦ 1.2) is more preferable.

  On the other hand, in cutting by dicing or the like, embossing using nanoimprint, etc., the surface roughness of the bottom surface of the circuit recess 3b of the pad portion 6b is greater than the surface roughness of the bottom surface of the circuit recess 3a of the wiring portion 6a. In order to increase the size, each of them may be mechanically cut, or a mold may be manufactured in advance and used. Then, electroless plating may be performed under the electroless plating conditions.

<Catalyst deposition process>
Next, as shown in FIG. 2C, the plating catalyst 4 is deposited on the entire surface of the circuit recess 3 formed on the insulating base 1 and the entire surface of the resin film 2 covering the insulating base 1. That is, the plating catalyst 4 is deposited on the entire surface where the circuit recess 3 is formed and the surface where the circuit recess 3 is not formed. Here, the plating catalyst 4 is a concept including its precursor.

  The plating catalyst 4 is a catalyst that is applied in advance in order to form an electroless plating film only on a portion where an electroless plating film is desired to be formed in a plating process described later. The plating catalyst 4 can be used without particular limitation as long as it is known as a catalyst for electroless plating. Alternatively, the precursor of the plating catalyst 4 may be deposited in advance, and the plating catalyst 4 may be generated after the resin film 2 is removed. Specific examples of the plating catalyst 4 include, for example, metal palladium (Pd), platinum (Pt), silver (Ag), and the like, and precursors that generate these.

  Examples of the method for depositing the plating catalyst 4 include a method of treating with an acidic Pd—Sn colloid solution treated under acidic conditions of pH 1 to 3 and then treating with an acid solution. More specifically, the following methods can be mentioned.

First, oil or the like adhering to the surface of the insulating base material 1 on which the circuit recesses 3 are formed is washed with hot water in a surfactant solution (cleaner / conditioner) for a predetermined time. Next, if necessary, a soft etching treatment is performed with a sodium persulfate-sulfuric acid based soft etching agent. And it pickles further in acidic solutions, such as sulfuric acid aqueous solution of pH 1-2, and aqueous hydrochloric acid. Next, a pre-dip treatment is performed in which chloride ions are adsorbed on the surface of the insulating substrate 1 by immersing in a pre-dip solution mainly composed of a stannous chloride aqueous solution having a concentration of about 0.1%. Thereafter, Pd and Sn are aggregated and adsorbed by further dipping in an acidic catalytic metal colloid solution such as acidic Pd—Sn colloid having pH 1 to 3 containing stannous chloride and palladium chloride. Then, an oxidation-reduction reaction (SnCl ₂ + PdCl ₂ → SnCl ₄ + Pd ↓) is caused between the adsorbed stannous chloride and palladium chloride. Thereby, the metal palladium which is the plating catalyst 4 is deposited.

  In addition, as an acidic catalyst metal colloid solution, a well-known acidic Pd-Sn colloid catalyst solution etc. can be used, and the commercially available plating process using an acidic catalyst metal colloid solution may be used. Such a process is systematized and sold by, for example, Rohm & Haas Electronic Materials.

  By such a catalyst deposition process, the plating catalyst 4 can be deposited on the surface of the resin film 2 and the surface of the circuit recess 3 as shown in FIG. 2C.

<Film removal process>
Next, as shown in FIG. 2D, the resin film 2 is removed by swelling or dissolving with a predetermined liquid. That is, when the resin film 2 is made of a soluble resin, the resin film 2 is dissolved using an organic solvent or an alkaline solution and removed from the surface of the insulating substrate 1. Further, when the resin film 2 is made of a swellable resin, the resin film 2 is swollen using a predetermined liquid, and peeled off from the surface of the insulating substrate 1 and removed. According to this step, by removing the resin film 2, as shown in FIG. 2D, the surface of the circuit recess 3 (the bottom surface of the circuit recess 3a of the wiring portion 6a and the circuit recess 3b of the pad portion 6b). The plating catalyst 4 can be left only on the bottom surface (including the bottom surface).

  According to this film removal process, the plating catalyst 4 can remain only on the surface of the insulating base material 1 where the circuit recesses 3 are formed. On the other hand, the plating catalyst 4 deposited on the surface of the resin film 2 is removed from the insulating substrate 1 together with the resin film 2. Here, from the viewpoint of preventing the plating catalyst 4 removed from the insulating base material 1 from being scattered and redepositing on the surface of the insulating base material 1, the resin film 2 is removed from the insulating base material 1. The thing which can be removed with the whole continuing, without collapsing apart is preferable.

  The liquid that dissolves or swells the resin film 2 is such that the resin film 2 can be easily dissolved or removed from the insulating substrate 1 without substantially decomposing or dissolving the insulating substrate 1 and the plating catalyst 4. Any liquid can be used without particular limitation as long as it can be dissolved or swelled. Such a liquid for removing the resin film can be appropriately selected depending on the type and thickness of the resin film 2. Specifically, for example, when a photocurable epoxy resin is used as the resist resin, an organic solvent, a resist remover in an alkaline aqueous solution, or the like is used. For example, when the resin film 2 is formed of an elastomer such as a diene elastomer, an acrylic elastomer, and a polyester elastomer, or as the resin film 2, (a) a polymerizable unsaturated group is included in the molecule. It is obtained by polymerizing at least one monomer of carboxylic acid or acid anhydride having at least one and at least one monomer that can be polymerized with (b) (a) monomer. In the case of a polymer resin to be produced, or a resin composition containing this polymer resin, or formed from the aforementioned carboxyl group-containing acrylic resin, for example, hydroxylation at a concentration of about 1 to 10% An aqueous alkali solution such as an aqueous sodium solution can be preferably used.

  In the case of using a plating process that is treated under acidic conditions as described above in the catalyst deposition step, the resin film 2 has a swelling degree of 60% or less, preferably 40% or less under acidic conditions, It is formed of an elastomer such as a diene elastomer, an acrylic elastomer, and a polyester elastomer that has a degree of swelling of 50% or more under alkaline conditions, or (a) polymerizable in the molecule. Polymerizing at least one monomer of carboxylic acid or acid anhydride having at least one unsaturated group and at least one monomer capable of polymerizing with (b) (a) monomer Or a resin composition containing this polymer resin, or the above-mentioned carboxyl group-containing acrylic resin. It is preferably formed from the system resin. Such a resin film is easily dissolved or swelled by being immersed in an alkaline aqueous solution having a pH of 11 to 14, preferably a pH of 12 to 14, such as a sodium hydroxide aqueous solution having a concentration of about 1 to 10%. Then, it is removed by dissolution or peeling. In addition, in order to improve solubility or peelability, you may irradiate with an ultrasonic wave during immersion. Moreover, you may remove by peeling with a light force as needed.

  Examples of the method for removing the resin film 2 include a method of immersing the insulating base material 1 coated with the resin film 2 in a resin film removal liquid for a predetermined time. Moreover, in order to improve dissolution removal property or peeling removal property, it is particularly preferable to irradiate ultrasonic waves during immersion. In addition, when it is difficult to remove or remove, for example, it may be peeled off with a light force as necessary.

<Plating process>
Next, as shown in FIG. 2E, electroless plating is performed on the insulating substrate 1 from which the film has been removed. By subjecting the insulating base 1 to electroless plating, an electroless plating film is formed in the circuit recess 3 where the plating catalyst 4 remains, and the circuit recess 3 is filled with a conductor 5 made of electroless plating for insulation. An electric circuit 6 is formed on the surface of the substrate 1. By such an electroless plating process, the electroless plating film is accurately deposited only on the portion where the circuit recess 3 is formed, and the electric circuit 6 is formed according to the circuit pattern.

  At this time, the plating catalyst 4 also remains on the bottom surface of the circuit recess 3a of the wiring portion 6a and the bottom surface of the circuit recess 3b of the pad portion 6b. It also grows from the bottom surface of the circuit recess 3a of the portion 6a and the bottom surface of the circuit recess 3b of the pad portion 6b. Therefore, the surface shape of the conductor 5 made of electroless plating follows the shape of the bottom surface of the circuit recess 3 and reflects it. As a result, a plurality of linear fine recesses are formed on the surface of the conductor 5 of the pad portion 6b in plan view, thereby forming a plurality of recesses and projections. On the other hand, such fine concave portions are not formed on the surface of the conductor 5 of the wiring portion 6a, and the concave and convex portions cannot be formed.

  As an electroless plating treatment method, the insulating base material 1 partially coated with the plating catalyst 4 is immersed in an electroless plating solution, and an electroless plating film is applied only to the portion where the plating catalyst 4 is applied. A method such as precipitation may be used.

  Examples of the metal used for electroless plating include copper (Cu), nickel (Ni), cobalt (Co), and aluminum (Al). Of these, plating mainly composed of Cu is preferable because of its excellent conductivity. Moreover, when Ni is included, it is preferable from the point which is excellent in corrosion resistance and adhesiveness with a solder.

  The film thickness of the electroless plating film is not particularly limited. Specifically, for example, it is preferably about 0.1 to 10 μm, more preferably about 1 to 5 μm.

  By the plating process, an electroless plating film is deposited only on the portion of the surface of the insulating substrate 1 where the plating catalyst 4 remains. Therefore, the conductor 5 made of electroless plating can be accurately formed only on the portion where the electric circuit 6 is to be formed. On the other hand, the deposition of the electroless plating film on the portion where the circuit recess 3 is not formed can be suppressed. Therefore, even when a plurality of fine wiring portions 6a having a narrow line width and a narrow line width are formed, an unnecessary plating film does not remain between the adjacent wiring portions 6a. Therefore, the occurrence of a short circuit and the occurrence of migration can be suppressed.

  By such a plating process, an electroless plating film can be deposited only on the laser-processed portion of the surface of the insulating substrate 1. Thereby, the embedded circuit 6 is formed on the surface of the insulating substrate 1. In this plating process, the electric circuit 6 is formed by filling the circuit recess 3 with the conductor 5 made of electroless plating. Therefore, the electroless plating plating film grows from the bottom surface of the circuit recess 3. Thus, the surface shape of the conductor 5 follows the shape of the bottom surface of the circuit recess 3, and therefore the surface shape of the conductor 5 of the pad portion 6 b is the shape of the bottom surface of the circuit recess 3 b of the pad portion 6 b. And the surface shape of the conductor 5 of the wiring portion 6a reflects and follows the shape of the bottom surface of the circuit recess 3a of the wiring portion 6a. The surface roughness of the conductor 5 of the pad portion 6b is linked to the fact that the surface roughness of the bottom surface of the circuit recess 3b of the pad portion 6b is larger than the surface roughness of the bottom surface of the circuit recess 3a of the wiring portion 6a. Is the conductor of the wiring portion 6a It become larger than the surface roughness of the.

  Through these steps, a circuit board 10 is manufactured in which an embedded electric circuit 6 having a wiring portion 6a and a pad portion 6b is provided on the surface of the insulating base 1 as shown in FIG. . In this circuit board 10, the surface roughness of the conductor 5 is different between the wiring portion 6a and the pad portion 6b. In particular, the surface roughness of the conductor 5 of the pad portion 6b is the surface roughness of the conductor 5 of the wiring portion 6a. It is bigger than that. As a result, as shown in FIG. 3, since the surface roughness of the conductor 5 is relatively large in the pad portion 6b, the adhesiveness of the solder when the component 20 such as a semiconductor chip is mounted on the pad portion 6b is improved. Thus, the mountability of the component 20 on the circuit board 10 is improved. In the wiring portion 6a, since the surface roughness of the conductor 5 is relatively small, the cross-sectional area of the wiring becomes almost constant, and the signal transmission speed is stabilized. That is, it is possible to achieve both the improvement of the component mounting property on the circuit board 10 and the stabilization of the signal transmission speed. In FIG. 3, reference numeral 30 denotes a semiconductor device in which the component 20 is mounted on the circuit board 10.

  Next, some modified examples of the pad portion 6b of the circuit board 10 will be described with reference to FIG. FIG. 4A shows a case where a lattice-shaped fine concave portion is formed on the surface of the conductor 5 of the pad portion 6b instead of forming a linear fine concave portion in a plan view. In this case, in the circuit pattern forming step, when the circuit recess 3b of the pad portion 6b is formed by cutting by laser processing, dicing, or the like, or by embossing using nanoimprinting, the circuit recess 3b A lattice-shaped fine recess is formed on the bottom surface in plan view. The surface shape of the conductor 5 (lattice-shaped fine recesses) reflecting the shape of the bottom surface is obtained by the growth of the electroless plating film.

  Similarly, FIG. 4B shows a case where a plurality of annular fine recesses having different diameters in a plan view are formed concentrically on the surface of the conductor 5 of the pad portion 6b. In this case, the pad portion 6b has a circular shape in plan view. FIG. 4C shows a case where a large number of dot-like fine recesses are formed side by side on the surface of the conductor 5 of the pad portion 6b in a plan view. In addition, in a plan view, fine concave portions such as a curved shape, a spiral shape, and a staggered shape may be formed, or by combining these shapes, in a circuit pattern forming process, laser processing, dicing processing, etc. The circuit recess 3b of the pad portion 6b may be formed by cutting or stamping using nanoimprint.

  In the embodiment described above, the surface roughness of the conductor 5 of the pad portion 6b is different from the surface roughness of the conductor 5 of the wiring portion 6a among the conductor portions 5a and 6b of the electric circuit 6 that are different from each other. The case where the surface roughness of the conductor 5 of the pad portion 6b is made smaller than the surface roughness of the conductor 5 of the wiring portion 6a is also included in the scope of the present invention. It is. In that case, there is an advantage that a decrease in fluidity of the resin sealing material during packaging can be suppressed, and a good package without voids can be obtained.

  Moreover, in the above embodiment, the bottom surface of the circuit recess 3b of the pad portion 6b out of the wiring portions 6a and the pad portions 6b in the electric circuit 6 in which the surface roughness of the bottom surface of the circuit recess 3 is different from each other. The surface roughness of the wiring portion 6a is made larger than the surface roughness of the bottom surface of the circuit recess 3a. In addition to this, the surface roughness of the bottom surface of the circuit recess 3a of the wiring portion 6a is set to the pad portion 6b. The case where the surface roughness of the bottom surface of the circuit recess 3b is larger than the surface roughness is also included in the scope of the present invention. In that case, in the wiring part 6a, there exists an advantage that the joining strength of the conductor 5 to the insulating base material 1 is excellent, and the dropping of the conductor 5 of the wiring part 6a from the insulating base material 1 is suppressed.

  In general, when the method for manufacturing the circuit board 10 according to the present embodiment illustrated in FIG. 2 is compared with the circuit formation technique by the CMP process illustrated in FIG. Since the polishing process is not performed as in the circuit forming technique by the process (in other words, the conductor 5 grows from the bottom surface of the circuit recess 3 and follows the shape of the bottom surface of the circuit recess 3 to leave it reflected. Therefore, the thickness of the conductor 5 cannot be varied as a whole in the electric circuit 6, and the reliability is maintained. On the other hand, since the polishing process is performed in the circuit forming technique based on the CMP process, the thickness of the conductor 5 can vary in the electric circuit 6, and the conductor 5 has a thick part in the lower part of the bottom surface of the circuit recess 3. In the portion where the bottom surface of the circuit recess 3 is high, the conductor 5 becomes a thin portion, and the reliability is lowered. Further, as a result of the polishing process, the conductor 5 is deleted, and the high portion of the bottom surface of the circuit recess 3 is exposed. If the pad portion 6b, the component 20 may not be mounted, and the wiring portion 6a. If so, there is a possibility that the signal cannot be transmitted.

  Hereinafter, the present invention will be described more specifically through examples. The scope of the present invention is not construed as being limited in any way by the following examples.

<Resin film formation process>
A 2 μm thick styrene-butadiene copolymer (SBR) film was formed on the surface of a 100 μm thick epoxy resin substrate (“R1766” manufactured by Panasonic Electric Works Co., Ltd.). The coating is formed on the main surface of the epoxy resin base material with methyl ethyl ketone (MEK) suspension of styrene-butadiene copolymer (SBR) (manufactured by Nippon Zeon Co., Ltd., acid equivalent 800, particle diameter 200 nm, solid content 15%. ) Was applied and dried at 80 ° C. for 30 minutes.

<Circuit pattern formation process>
Next, a circuit recess having a wiring portion having a width of 20 μm and a depth of 30 μm and a pad portion having a predetermined width and depth was formed by laser processing on the epoxy resin base material on which the film was formed. For laser processing, MODEL 5330 manufactured by ESI equipped with a UV-YAG laser was used. Then, when the 10-point average roughness (RzPB) of the bottom surface of the circuit recess of the obtained pad portion and the 10-point average roughness (RzLB) of the bottom surface of the circuit recess of the obtained wiring portion were determined, RzPB, RzLB) was also in the range of 0.01-100 μm. Moreover, when the ratio (RzPB / RzLB) of (RzPB) to (RzLB) was determined, it was 2 or more ((RzPB / RzLB) ≧ 2).

<Catalyst deposition process>
Next, the epoxy resin base material in which the circuit recesses were formed was immersed in a cleaner / conditioner (surfactant solution, pH <1: “C / N 3320” manufactured by Rohm & Haas Electronic Materials Co., Ltd.), and then washed with water. . Then, soft etching treatment was performed with a sodium persulfate-sulfuric acid-based soft etchant having a pH <1. Then, a pre-dip process was performed using PD404 (manufactured by Shipley Far East, pH <1). Then, by immersing in an acidic Pd—Sn colloidal solution “CAT44” (manufactured by Shipley Far East Co., Ltd.) having a pH of 1 containing stannous chloride and palladium chloride, palladium serving as the core of electroless copper plating is tin-palladium colloid. It was made to adsorb | suck to an epoxy resin base material in the state of. And the palladium nucleus was generated by immersing in accelerator chemical solution "ACC19E" (made by Shipley Far East) of pH <1.

<Film removal process>
Next, the epoxy resin substrate was immersed in a 5% aqueous sodium hydroxide solution having a pH of 14 for 10 minutes while being subjected to ultrasonic treatment. As a result, the SBR coating on the surface swelled and peeled cleanly. At this time, no SBR coating fragments remained on the epoxy resin substrate surface.

<Plating process>
Next, the epoxy resin base material was immersed in an electroless plating solution (CM328A, CM328L, CM328C, manufactured by Shipley Far East) to perform an electroless copper plating process. An electroless copper plating film having a thickness of 3 to 5 μm was deposited by the electroless copper plating treatment. When the surface of the epoxy base material subjected to the electroless copper plating treatment was observed with an SEM (scanning microscope), the electroless copper plating film was accurately embedded only in the portion where the circuit recess was formed. And the 10-point average roughness (RzPT) of the surface of the electroless copper plating film of the obtained pad part and the 10-point average roughness (RzLT) of the surface of the electroless copper plating film of the obtained wiring part were calculated | required. However, both (RzPT, RzLT) were in the range of 0.01 to 100 μm. Further, when the ratio (RzPT / RzLT) of (RzPT) to (RzLT) was determined, it was 2 or more ((RzPT / RzLT) ≧ 2). Furthermore, when the ratio (RzT / RzB) between the ten-point average roughness (RzT) of the surface of the obtained electroless copper plating film and the ten-point average roughness (RzB) of the bottom surface of the recess for the circuit was determined, 0 0.1 or more and 2.0 or less (0.1 ≦ (RzT / RzB) ≦ 2.0).

DESCRIPTION OF SYMBOLS 1 Insulation base material 2 Resin film 3 Circuit recessed part 3a Circuit recessed part 3b of a wiring part Circuit recessed part 4 of a pad part 4 Plating catalyst 5 Conductor 6 Electrical circuit 6a Wiring part 6b Pad part 10 Circuit board 20 Component 30 Semiconductor device

Claims (13)

A circuit board provided with an electric circuit having a wiring part and a pad part on the surface of an insulating base material,
The electric circuit has a configuration in which a conductor is embedded in a circuit recess provided on the surface of an insulating substrate,
The circuit board characterized in that the surface roughness of the conductor is different between the wiring part and the pad part in the electric circuit.   2. The circuit board according to claim 1, wherein the surface roughness of the conductor of the pad portion is larger than the surface roughness of the conductor of the wiring portion.   The ratio (RzPT / RzLT) of the ten-point average roughness (RzPT) of the surface of the conductor of the pad portion to the ten-point average roughness (RzLT) of the surface of the conductor of the wiring portion is 2 or more ((RzPT / RzLT) ≧ 2 The circuit board according to claim 2, wherein:   The surface roughness of the conductor of the pad portion is formed on the surface of the conductor of the pad portion by forming fine concave portions in a linear shape, a curved shape, a lattice shape, an annular shape, a spiral shape, a staggered shape and / or a dot shape in plan view. The circuit board according to claim 2, wherein is larger than the surface roughness of the conductor of the wiring portion.   A linear, curved, latticed, annular, spiral, staggered, and / or dot-shaped fine recess is formed on the bottom surface of the circuit recess in the pad portion. 5. The circuit board according to claim 4, wherein the fine recesses are formed on the surface of the conductor of the pad portion by the conductor following the shape of the bottom surface.   The ratio (RzT / RzB) of the ten-point average roughness (RzT) of the surface of the conductor to the ten-point average roughness (RzB) of the bottom surface of the circuit recess is 0.1 to 2.0 (0.1 ≦ The circuit board according to claim 5, wherein (RzT / RzB) ≦ 2.0). A circuit board provided with an electric circuit having a wiring part and a pad part on the surface of an insulating base material,
The electric circuit has a configuration in which a conductor is embedded in a circuit recess provided on the surface of an insulating substrate,
The circuit board, wherein the surface roughness of the bottom surface of the circuit recess is different between the wiring part and the pad part in the electric circuit.   8. The circuit board according to claim 7, wherein the surface roughness of the bottom surface of the circuit recess in the pad portion is larger than the surface roughness of the bottom surface of the circuit recess in the wiring portion.   The ratio (RzPB / RzLB) of the 10-point average roughness (RzPB) of the bottom surface of the circuit recess in the pad portion to the 10-point average roughness (RzLB) of the bottom surface of the circuit recess in the wiring portion is 2 or more ((RzPB / 9. The circuit board according to claim 8, wherein RzLB) ≧ 2).   A circuit recess in the pad portion is formed by forming a linear, curved, latticed, annular, spiral, staggered and / or dot-like fine recess in the bottom surface of the circuit recess in the pad portion. 9. The circuit board according to claim 8, wherein the surface roughness of the bottom surface of the circuit board is larger than the surface roughness of the bottom surface of the circuit recess of the wiring portion.   As the conductor follows the shape of the bottom surface of the circuit recess of the pad portion, the surface of the pad portion conductor is linear, curved, latticed, annular, spiral, staggered and / or dot-like in plan view. The circuit board according to claim 10, wherein a fine recess is formed.   The ratio (RzT / RzB) of the ten-point average roughness (RzT) of the surface of the conductor to the ten-point average roughness (RzB) of the bottom surface of the circuit recess is 0.1 to 2.0 (0.1 ≦ The circuit board according to claim 11, wherein (RzT / RzB) ≦ 2.0).   The semiconductor device by which components were mounted in the said pad part of the circuit board of any one of Claims 1-12.

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