JP5282487B2 - Multilayer printed wiring board manufacturing method, multilayer printed wiring board, and semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing a multilayer printed wiring board having a high insulating reliability and an excellent signal responsiveness even in a multilayer printed wiring board on which fine wirings are formed, and to provide a multilayer printed wiring board obtained by the method, and a semiconductor apparatus. <P>SOLUTION: A method of a multilayer printed wiring board configured by laminating insulating layers composed of a resin composition including a thermosetting resin on at least one surface side of a substrate includes: a laminating step of laminating insulating layers with carrier layers on at least one surface side of the substrate while heating the insulating layers to obtain a laminate; a piercing step of irradiating laser at a predetermined part of the laminate to form a hole penetrating the carrier layer and the insulating layer; a desmear step of carrying out a desmear process to an inner surface of the hole; and a peeling step of peeling off the carrier layer from the laminate. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for manufacturing a multilayer printed wiring board, a multilayer printed wiring board, and a semiconductor device.

  In recent years, electronic devices have been required to be reduced in size, weight, and performance, and the same requirements have been increasing in advanced package materials. In the multilayer printed wiring board which is one of the leading package materials, miniaturization and high density of wiring are progressing.

  As a method for forming the wiring of the multilayer printed wiring board, a semi-additive method is often applied. In this wiring forming method, a circuit pattern is formed through a step of irradiating a laser to form a hole penetrating the insulating layer in a predetermined portion of the laminate, a step of desmearing the surface, and an electroless plating step. It includes a step of forming with a resist, a step of forming a wiring by electrolytic plating, a step of removing the resist, a step of removing an exposed portion of the electroless plating film by flash etching, and the like.

  Conventionally, in the desmear process described above, the surface of the insulating layer is roughened with a chemical etching solution to increase the unevenness of the surface of the insulating layer, and the anchoring effect ensures the adhesion between the insulating layer and the conductor layer. I have done it.

  However, the roughening with the above-described chemical etching solution may hinder the miniaturization of the wiring. That is, when the surface roughness of the insulating layer is large, it takes time for flash etching to remove the plating residue remaining in the recess. If this flash etching is performed for a long time, there is a risk of damaging the fine wiring, which may reduce the insulation reliability.

Furthermore, in recent years, there has been an increasing demand for transmission and processing of large-capacity information with low loss and high speed, and with the demand for forming fine wiring on a multilayer printed wiring board, the frequency of electrical signals passing through the wiring is increasing.
However, in the above-mentioned semi-additive method, since the surface of the insulating layer is roughened, the roughness of the conductor layer formed thereon tends to increase. If the surface of the conductor layer is rough, the transmission loss increases due to the skin effect, and this influence becomes more conspicuous as the signal becomes higher in frequency and hinders securing of signal response (for example, see Patent Document 1).

  Therefore, in a fine wiring region where the line and space ratio (L / S) of the conductor layer circuit is, for example, about 10 μm / 10 μm, the printed wiring board and the wiring forming method have high electrical reliability and excellent signal response. Is now required.

JP 2007-254710 A

An object of the present invention is to provide a method for manufacturing a multilayer printed wiring board having high insulation reliability and excellent signal response even in a multilayer printed wiring board in which fine wiring is formed, and a multilayer printed wiring board obtained by the method. Is to provide.
Another object of the present invention is to provide a semiconductor device having excellent insulation reliability and excellent signal response.

Such an object is achieved by the present invention described in the following (1) to (11).
(1) A method for producing a multilayer printed wiring board, in which an insulating layer made of a resin composition containing a thermosetting resin is laminated on at least one surface side of a substrate, wherein at least one surface side of the substrate Laminating step of laminating an insulating layer with a carrier layer while heating to obtain a laminated body, and a perforating step of irradiating a predetermined portion of the laminated body with a laser to form a hole penetrating the carrier layer and the insulating layer; A method for producing a multilayer printed wiring board, comprising: a desmearing process for desmearing the inner surface of the hole; and a peeling process for peeling the carrier layer from the laminate after the desmearing process.
(2) The method according to (1), further including an irradiation step of modifying the surface of the insulating layer by irradiating the surface of the insulating layer with an energy beam through a carrier layer before the peeling step. A method for producing a multilayer printed wiring board.
(3) The method for producing a multilayer printed wiring board according to (1), further comprising an irradiation step of modifying the surface of the insulating layer by irradiating the surface of the insulating layer with an energy ray after the peeling step. .
(4) Manufacture of the multilayer printed wiring board in any one of said (1) thru | or (3) whose arithmetic surface roughness (Ra) of the surface of the said insulating layer after the said irradiation process is 0.1 micrometer or less. Method.
(5) The method for producing a multilayer printed wiring board according to any one of (1) to (4), wherein the insulating layer with a carrier layer has a release layer between the carrier layer and the insulating layer.
(6) The method for producing a multilayer printed wiring board according to any one of (1) to (5), wherein the carrier layer is a polyester film.
(7) The thermosetting resin according to any one of (1) to (6), wherein the thermosetting resin includes at least one resin selected from an epoxy resin, a phenol resin, a cyanate resin, and a benzocyclobutene resin. A method for producing a multilayer printed wiring board.
(8) The method for producing a multilayer printed wiring board according to any one of (2) to (7), wherein the energy rays are ultraviolet rays.
(9) A multilayer printed wiring board obtained by the method for producing a multilayer printed wiring board according to any one of (1) to (8).
(10) The multilayer printed wiring board according to the above (9), wherein the arithmetic surface roughness (Ra) of the surface of at least one insulating layer is 0.1 μm or less.
(11) A semiconductor device comprising a semiconductor element mounted on the multilayer printed wiring board according to (9) or (10).

According to the present invention, a multilayer printed wiring board having high insulation reliability and excellent signal response even in a multilayer printed wiring board in which fine wiring is formed, and the multilayer printed wiring board obtained by the method Can be provided.
Moreover, according to the present invention, it is possible to provide a semiconductor device having excellent insulation reliability and excellent signal response.

Hereinafter, a method for manufacturing a multilayer printed wiring board, a multilayer printed wiring board, and a semiconductor device of the present invention will be described.
The method for producing a multilayer printed wiring board according to the present invention is a method for producing a multilayer printed wiring board in which an insulating layer made of a resin composition containing a thermosetting resin is laminated on at least one side of a substrate. And laminating the insulating layer with the carrier layer on at least one surface side of the substrate while heating to obtain a laminated body, and irradiating a predetermined portion of the laminated body with a laser to form the carrier layer and the insulating layer. It has a drilling process for forming a through-hole, a desmear process for desmearing the inner surface of the hole, and a peeling process for peeling the carrier layer from the laminate after the desmear process. .
Moreover, the multilayer printed wiring board of the present invention is obtained by the above-described manufacturing method.
The semiconductor device of the present invention is characterized in that a semiconductor element is mounted on the multilayer printed wiring board described above.

  First, the manufacturing method of a multilayer printed wiring board is demonstrated in detail based on suitable embodiment.

  1 and 2 are cross-sectional views showing an example of a method for manufacturing a multilayer printed wiring board. The manufacturing method of the multilayer printed wiring board of the present embodiment includes a laminating process, a perforating process, a desmear process, a peeling process, an energy ray irradiation process, an electroless plating process, a resist forming process, an electrolytic plating process, A resist stripping process and an etching process are provided.

(Lamination process)
Insulation with a carrier layer composed of the resin composition containing the thermosetting resin shown in FIG. 1B on the surface of the substrate 1 shown in FIG. 1A and the inner layer circuit 2 formed on the substrate 1 The layer 3 is laminated while being heated to form a laminate 4 (FIG. 1B).
Here, as a method of laminating while heating, a method using a vacuum pressurizing laminator device, a flat plate press device or the like can be mentioned.

  For example, when using a vacuum pressurizing laminator device, the insulating layer 31 of the insulating layer with carrier layer 3 and the inner layer circuit 2 of the substrate 1 are stacked so as to be adjacent to each other, and vacuum heating is applied by the vacuum pressurizing laminator device. The laminated body 4 can be obtained by press-molding, laminating, and then heat-curing with a hot air dryer or the like.

Here, the conditions for vacuum heating and pressure molding are not particularly limited, but can be carried out at a temperature of 60 to 160 ° C. and a pressure of 0.2 to 3 MPa, for example.
Moreover, although the conditions to heat-harden are not specifically limited, For example, it can implement in temperature 100-240 degreeC and time 10 to 120 minutes. In the heat curing, the degree of cure of the resin composition constituting the insulating layer 31 is preferably measured by a differential scanning calorimeter (hereinafter referred to as DSC) to a cured state of 5 to 95%. It is more preferable to make it a 45-90% hardening state. This is because the degree of cure can be expected to improve the adhesion utilizing the thermosetting shrinkage of the resin after plating in the subsequent step. Here, the degree of cure measured by a differential scanning calorimeter (hereinafter referred to as DSC) can be calculated by the following equation (Equation I).

  Curing degree [%] = {1- (residual calorific value of resin after heat curing) / (residual calorific value of resin before heat curing)} * 100 (several I)

  For example, when using a flat plate pressing apparatus, the insulating layer 31 of the insulating layer with carrier layer 3 and the inner layer circuit 2 of the substrate 1 are stacked so as to be adjacent to each other, and are heated and pressed by the flat plate pressing apparatus, The laminated body 4 can be obtained.

  Here, the conditions for heat-press molding in the flat plate press apparatus are not particularly limited, but can be carried out at a temperature of 140 to 240 ° C. and a pressure of 1 to 4 MPa, for example. It is desirable to obtain a cured state with a degree of cure of 5 to 95% as measured by a differential scanning calorimeter (hereinafter referred to as DSC). More preferably, the degree of cure is 45 to 90%.

  The substrate 1 having the inner layer circuit 2 on the surface is preferably a substrate in which a predetermined conductor circuit is formed on both surfaces of a copper-clad laminate by etching or the like, and the conductor circuit portion is roughened such as blackening treatment. Can be used.

Next, the resin composition used for the insulating layer 31 will be described. The resin composition is composed of a resin composition containing a thermosetting resin. Thereby, the heat resistance of the insulating layer 31 can be improved.
Examples of the thermosetting resin include novolak type phenol resins such as phenol novolak resin, cresol novolak resin, bisphenol A novolak resin, unmodified resol phenol resin, oil-modified resole phenol modified with tung oil, linseed oil, walnut oil, and the like. Phenolic resin such as resol type phenol resin such as resin, bisphenol A epoxy resin, bisphenol F epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol Z type epoxy resin, bisphenol P type epoxy resin, bisphenol M type epoxy Bisphenol type epoxy resin such as bisphenol type epoxy resin such as resin, novolak type epoxy resin such as phenol novolak type epoxy resin, cresol novolak type epoxy resin, etc. Biphenyl aralkyl type epoxy resin, aryl alkylene type epoxy resin, naphthalene type epoxy resin, anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin, adamantane type epoxy resin, fluorene type epoxy resin, etc. Resin having triazine ring such as epoxy resin, urea (urea) resin, melamine resin, unsaturated polyester resin, bismaleimide resin, polyimide resin, polyamideimide resin, polyurethane resin, diallyl phthalate resin, silicone resin, benzoxazine ring Examples thereof include resins, triazine resins, benzocyclobutene resins, and cyanate resins. Among these, one or more resins selected from epoxy resins, phenol resins, cyanate resins, and benzocyclobutene resins are preferable, and cyanate resins are particularly preferable. Thereby, the thermal expansion coefficient of the insulating layer 31 can be made small. Furthermore, the insulating layer 31 is excellent in electrical characteristics (low dielectric constant, low dielectric loss tangent), mechanical strength, and the like.

  Specific examples of the cyanate resin include novolak-type cyanate resins, bisphenol A-type cyanate resins, bisphenol E-type cyanate resins, and bisphenol-type cyanate resins such as tetramethylbisphenol F-type cyanate resins. Among these, novolac type cyanate resin is preferable. The novolac type cyanate resin can be represented by, for example, the formula (I). The novolac-type cyanate resin can reduce the thermal expansion coefficient of the insulating layer, and is excellent in the mechanical strength and electrical characteristics (low dielectric constant, low dielectric loss tangent) of the insulating layer 31.

Although the weight average molecular weight of the cyanate resin is not particularly limited, a weight average molecular weight of 500 to 4,500 is preferable, and 600 to 3,000 is particularly preferable. When the weight average molecular weight is less than the lower limit, the mechanical strength of the cured product of the insulating layer 31 may be reduced, and when the insulating layer 31 is produced, tackiness may occur and transfer of the resin may occur. There is. Further, when the weight average molecular weight exceeds the above upper limit, the curing reaction is accelerated, and when a substrate (particularly, a circuit substrate) is formed, molding defects may occur or the interlayer peel strength may be reduced.
The weight average molecular weight of the cyanate resin or the like can be measured by, for example, GPC (gel permeation chromatography, standard substance: converted to polystyrene).

  In addition, although not particularly limited, the cyanate resin can be used alone, including its derivatives, or two or more having different weight average molecular weights can be used together, or one or two or more thereof. These prepolymers can also be used in combination.

  Although content of the said thermosetting resin is not specifically limited, 5 to 50 weight% of the whole said resin composition is preferable, and 10 to 40 weight% is especially preferable. If the content is less than the lower limit, it may be difficult to form the insulating layer 31, and if the content exceeds the upper limit, the strength of the insulating layer 31 may be reduced.

  When a cyanate resin (particularly a novolac-type cyanate resin) is used as the thermosetting resin, it is preferable to use an epoxy resin (substantially free of halogen atoms) in combination. Examples of the epoxy resin include bisphenol A type epoxy resin, bisphenol F type epoxy resin, bisphenol E type epoxy resin, bisphenol S type epoxy resin, bisphenol Z type epoxy resin, bisphenol P type epoxy resin, and bisphenol M type epoxy resin. Bisphenol type epoxy resins, phenol novolac type epoxy resins, cresol novolac type epoxy resins and other novolac type epoxy resins, biphenyl type epoxy resins, xylylene type epoxy resins, biphenyl aralkyl type epoxy resins and other aryl alkylene type epoxy resins, naphthalene type epoxy resins , Anthracene type epoxy resin, phenoxy type epoxy resin, dicyclopentadiene type epoxy resin, norbornene type epoxy resin, adamanta Type epoxy resins, fluorene type epoxy resins and the like. As the epoxy resin, one of these can be used alone, or two or more having different weight average molecular weights are used in combination, or one or two or more thereof and a prepolymer thereof are used in combination. You can also. Among these epoxy resins, aryl alkylene type epoxy resins are particularly preferable. Thereby, moisture absorption solder heat resistance and a flame retardance can be improved.

  The arylalkylene-type epoxy resin refers to an epoxy resin having one or more arylalkylene groups in a repeating unit. For example, a xylylene type epoxy resin, a biphenyl dimethylene type epoxy resin, etc. are mentioned. Among these, a biphenyl dimethylene type epoxy resin is preferable. A biphenyl dimethylene type | mold epoxy resin can be shown, for example by Formula (II).

  The average repeating unit n of the biphenyl dimethylene type epoxy resin represented by the formula (II) is not particularly limited, but is preferably 1 to 10, and particularly preferably 2 to 5. When the average repeating unit n is less than the lower limit, the biphenyl dimethylene type epoxy resin is easily crystallized, and the solubility in a general-purpose solvent is relatively lowered, which may make handling difficult. On the other hand, if the average repeating unit n exceeds the upper limit, the fluidity of the resin is lowered, which may cause molding defects. By setting the number of average repeating units n within the above range, it is possible to achieve an excellent balance of these characteristics.

  Although content of the said epoxy resin is not specifically limited, 1 to 55 weight% of the whole resin composition is preferable, and 5 to 40 weight% is especially preferable. If the content is less than the lower limit, the reactivity of the cyanate resin may decrease, or the moisture resistance of the resulting product may decrease. If the content exceeds the upper limit, the low thermal expansion and heat resistance will decrease. There is a case.

The weight average molecular weight of the epoxy resin is not particularly limited, but a weight average molecular weight of 500 to 20,000 is preferable, and 800 to 15,000 is particularly preferable. When the weight average molecular weight is less than the lower limit, tackiness may occur on the surface of the insulating layer, and when the upper limit is exceeded, solder heat resistance may be reduced. By setting the weight average molecular weight within the above range, it is possible to achieve an excellent balance of these characteristics.
The weight average molecular weight of the epoxy resin can be measured by GPC, for example.

Although it does not specifically limit to the said resin composition, It is preferable that an inorganic filler is included. Thereby, improvement of low thermal expansibility and a flame retardance can be aimed at. The elastic modulus can be improved by a combination of the cyanate resin (particularly a novolac-type cyanate resin) and an inorganic filler.
Examples of the inorganic filler include silicates such as talc, calcined clay, unfired clay, mica and glass, oxides such as titanium oxide, alumina, silica and fused silica, calcium carbonate, magnesium carbonate, hydrotalcite and the like. Carbonates, hydroxides such as aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sulfates or sulfites such as barium sulfate, calcium sulfate, calcium sulfite, zinc borate, barium metaborate, aluminum borate, boron Examples thereof include borates such as calcium oxide and sodium borate, nitrides such as aluminum nitride, boron nitride, silicon nitride, and carbon nitride, titanates such as strontium titanate and barium titanate. As the inorganic filler, one of these can be used alone, or two or more can be used in combination. Among these, silica is particularly preferable, and fused silica (particularly spherical fused silica) is preferable in terms of excellent low thermal expansion. There are crushed and spherical shapes, but in press molding, use a method that suits the purpose, such as using spherical silica to lower the melt viscosity of the resin composition in order to ensure the embedding of the inner layer circuit. Is done.

  Although it does not specifically limit as an average particle diameter of the said inorganic filler, It is preferable that it is 0.01-5.0 micrometers. More preferably, it is 0.1-2.0 micrometers. When the average particle size of the inorganic filler is less than the lower limit, when preparing the resin varnish using the resin composition, the viscosity of the resin varnish becomes high, and therefore work for preparing an insulating layer with a carrier layer. May affect sex. On the other hand, if the upper limit is exceeded, phenomena such as sedimentation of the inorganic filler may occur in the resin varnish. By making the average particle diameter of the inorganic filler within the above range, it is possible to achieve an excellent balance of these characteristics.

  The inorganic filler is not particularly limited, but an inorganic filler having a monodispersed average particle diameter can be used, and an inorganic filler having a polydispersed average particle diameter can be used. Furthermore, one type or two or more types of inorganic fillers having an average particle size of monodispersed and / or polydispersed may be used in combination.

Although content of the said inorganic filler is not specifically limited, It is preferable that it is 20 to 70 weight% of the whole resin composition. More preferably, it is 30 to 60% by weight.
If the content of the inorganic filler is less than the lower limit, the effect of imparting low thermal expansion and low water absorption may be reduced. Moreover, when the said upper limit is exceeded, the moldability of an insulating layer may fall by the fall of the fluidity | liquidity of a resin composition. By making content of an inorganic filler into the said range, it can be set as the thing excellent in the balance of these characteristics.

  In addition, the resin composition may include a film-forming resin, a curing accelerator, a coupling agent, a pigment, a dye, an antifoaming agent, a leveling agent, an ultraviolet absorber, a foaming agent, an antioxidant, You may add additives other than the said components, such as a flame retardant and an ion trapping agent.

Here, the method for forming the resin composition on the carrier layer 32 is not particularly limited. For example, the resin varnish is prepared by dissolving and dispersing the resin composition in a solvent or the like, and using various coater apparatuses. And a method of drying the resin varnish on the carrier layer 32 using a spray device, and then drying the resin varnish.
Among these, it is preferable to apply a resin varnish to the carrier layer 32 using various coaters such as a comma coater and a die coater, and then dry the resin varnish. Thereby, the insulating layer 3 with a carrier layer having no void and having a uniform thickness of the insulating layer 31 can be efficiently manufactured.

The solvent used in the resin varnish desirably exhibits good solubility in the resin component in the resin composition, but a poor solvent may be used within a range that does not adversely affect the resin varnish. Examples of the solvent exhibiting good solubility include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, ethylene glycol, cellosolve and carbitol.
Although it does not specifically limit as solid content in the said resin varnish, 30 to 80 weight% is preferable and especially 40 to 70 weight% is preferable.

  Although it does not specifically limit as thickness of the insulating layer 31, It is preferable that it is 5-100 micrometers. More preferably, it is 10-80 micrometers. Thereby, when manufacturing a multilayer printed wiring board using the insulating layer 3 with a carrier layer, the unevenness | corrugation of an inner-layer circuit can be filled and shape | molded and suitable insulating layer thickness can be ensured. Moreover, in the insulating layer 3 with a carrier layer, generation | occurrence | production of the crack of an insulating layer can be suppressed and powder fall at the time of cutting can be decreased.

  Further, the type of the carrier layer 32 is not particularly limited. For example, a polyolefin film such as polyethylene or polypropylene, a polyester film such as polyethylene terephthalate, polybutylene terephthalate, or polyethylene naphthalate, a polyphenylene sulfide film, a polyvinyl chloride film, a polystyrene film, A polycarbonate film, a polyacrylonitrile film, a fluororesin film, a polyimide film, a polyamide film, a cyclohexane resin film, a cyclohexene resin film, and the like can be given. Among these, a polyester film is preferable. Thereby, the carrier layer 32 can endure the process in each process of a lamination process, a perforation process, a desmear process, and an energy ray irradiation process. That is, it is excellent in heat resistance, chemical resistance, acid resistance, and alkali resistance.

  Although the thickness of the carrier layer 32 is not specifically limited, 10-80 micrometers is preferable. When the thickness is within the above range, it is excellent in handling at the time of peeling. In particular, in the step of irradiating energy rays, the energy rays 61 can be efficiently transmitted, and the adhesion between the resin and the plating can be improved.

  The thickness of the insulating layer 3 with a carrier layer is not particularly limited, but a 20 to 160 μm thickness is preferable because the handleability during production is good.

  In manufacturing the insulating layer 3 with the carrier layer, it is preferable that the unevenness on the surface of the insulating base to be joined to the insulating layer 31 is as small as possible. It is preferable that the surface of the insulating layer 31 before UV irradiation has an arithmetic surface roughness (Ra) of 0.05 μm or less. Thereby, the effect | action of this invention can be expressed effectively.

  The surface of the carrier layer 32 that contacts the insulating layer 31 is not particularly limited, but a release agent is preferably applied. Thereby, it becomes easy to peel the carrier layer 32 from the insulating layer 31.

(Punching process)
In the perforation process shown in FIG. 1C, the laminated body 4 is irradiated with a laser 6 to form the holes 5 penetrating the insulating layer 31 and the carrier layer 32 (FIG. 1D). That is, before the carrier layer 32 is peeled off, a hole 5 (via hole) is formed in the insulating layer by irradiation of the laser 6. Thus, since the laser 6 is irradiated and punched in the state in which the carrier layer 32 is laminated, it is possible to suppress scattering of smear, which is a resin carbide shaved by the laser 6. Furthermore, it is also possible to prevent resin destruction around the hole 5 by the first-order diffracted wave of the laser 6.

  The type of laser used for irradiation with the laser 6 is not particularly limited, but an excimer laser, a UV-YAG laser, a carbon dioxide gas laser, or the like is suitable for fine processing and is preferable. Moreover, although the hole diameter of the hole 5 is not specifically limited, 10-150 micrometers is preferable and 20-100 micrometers is more preferable on fine wiring formation.

(Desmear process)
Next, in the desmear process, the holes 5 formed in the drilling process are treated with a chemical etching solution to remove smears remaining on the inner wall and bottom of the holes 5 generated in the drilling process. Examples of the chemical etching solution used here include oxidizing agents such as permanganate and dichromic acid. With the oxidizing agent, it is possible to efficiently remove smear remaining on the inner wall and bottom of the hole 5 generated in the drilling process.

In the method for manufacturing a multilayer printed wiring board according to the present invention, the desmear process is performed in a state where the carrier layer 32 is laminated.
Conventionally, by using a chemical etching solution in the desmear process, a roughening process for forming irregularities on the surface of the insulating layer 31 is performed along with removal of smear remaining on the inner wall and bottom of the hole 5. However, if the unevenness is increased, adhesion between the resin and the plating can be achieved. However, if the surface roughness of the insulating layer 31 is large, the conductor circuit formed in the subsequent process also has large unevenness, resulting in a large signal transmission loss. . However, in the present invention, since the desmear process is performed with the carrier layer 32 laminated, the carrier layer 32 prevents contact between the surface of the insulating layer 31 and the chemical etching solution, and increases the unevenness of the surface of the insulating layer 31. In addition, it is possible to efficiently remove only the smear remaining inside the hole 5. Thereby, the transmission loss of a signal becomes small and the multilayer printed wiring board excellent in signal responsiveness can be manufactured.

(Energy beam irradiation process)
Next, the laminated body 4 that has undergone the desmear process is irradiated with the energy beam 61 through the carrier layer 32 in the energy beam irradiation process to modify the surface of the insulating layer 31 (FIG. 1E).

  The energy ray 61 is preferably ultraviolet rays or the like in the wavelength region, and more preferably irradiated with ultraviolet rays generated from a high-pressure mercury lamp, a barrier discharge excimer lamp, a low-pressure mercury lamp, an excimer lamp, krypton, an in-chamber discharge or the like. Furthermore, among these, a barrier discharge excimer lamp, a low-pressure mercury lamp, and an excimer lamp are more preferable. In these lamps, ultraviolet rays having a short wavelength effective for modifying the surface of the insulating layer 31 can be efficiently generated. The short wavelength here refers to a region of 300 nm or less.

Also, preferably the region of ^2mW / cm ^{2 ~1000mW} / cm 2 as the illuminance of ultraviolet rays. Further areas of 20mW ^/ cm ² ~200mW ^/ cm 2 is more preferable. Irradiation with ultraviolet rays in this illuminance region does not cause the irradiation environment to become high temperature, and it is possible to perform higher surface modification in a short time. The arithmetic surface roughness (Ra) of the insulating layer 31 after irradiation is 0.1 μm. The following is maintained: Moreover, in this condition area | region, it is thought that the adhesiveness of resin and plating is improved more by irradiating the energy ray 61 and activating the surface of the insulating layer 31, and producing a nano-order throwing effect.

(Peeling process)
In the peeling step, the carrier layer 32 is peeled from the laminate 4 to expose the insulating layer 31 (FIG. 1 (f)). As described above, the carrier layer 32 is peeled off after the energy ray irradiation step, whereby the insulating layer 31 can be further prevented from being contaminated with dust or the like.

  In this embodiment, the energy ray irradiation process is performed before the peeling process. However, the present invention is not limited to this, and the carrier layer 32 is peeled from the laminate 4 after the desmear process and after the peeling process. Then, after the insulating layer 31 is exposed, the surface of the insulating layer 31 may be modified by an energy ray irradiation process. In addition, the surface treatment modification can be efficiently performed by irradiating the energy beam after peeling the carrier layer 32 in this way.

(Electroless plating process)
In the electroless plating step shown in FIG. 2G, the electroless plating layer 8 is formed on the surface of the insulating layer 31, the inner layer circuit 2, and the inner walls of the holes 5 by an electroless plating process.

  The type of metal of the electroless plating layer is not particularly limited, but copper, nickel and the like are preferable. These metals have good adhesion between the insulating layer and the electroless plating. The thickness of the electroless plating layer 8 is not particularly limited, but is preferably about 0.1 to 5 μm. Furthermore, after the electroless plating, by performing heat treatment at 150 ° C. to 200 ° C. for 10 minutes to 120 minutes with a hot air drying apparatus, the adhesion between the insulating layer 31 and the electroless plating layer 8 can be improved.

(Resist formation process)
In the resist formation step shown in FIG. 2 (h), a plating resist 9 is formed on the electroless plating layer 8 in order to form a circuit pattern.

  The thickness of the plating resist 9 is preferably about the same as or thicker than the thickness of the conductor to be subsequently plated. Examples of the resin that can be used for the plating resist include a dry film and a liquid resist.

(Electrolytic plating process)
In the electrolytic plating step shown in FIG. 2 (i), the electrolytic plating layer 10 is formed by an electrolytic plating process, and a wiring pattern is formed.

  For the electrolytic plating, copper sulfate electrolytic plating can be used. The thickness of the electrolytic plating layer is not particularly limited, but is preferably about 5 to 50 μm. Thereby, it becomes a plating circuit with high electrical reliability.

(Resist stripping process)
In the resist stripping step shown in FIG. 2 (j), the plating resist 9 is removed with a resist stripping solution or the like.

(Etching process)
In the etching step shown in FIG. 2 (k), the exposed electroless copper plating portion other than the portion to be the conductor circuit 11 is removed by etching to form a circuit pattern.

  In this etching step, it is preferable to use a high-pressure spray or the like. The type of etching solution used is not limited, but ferric chloride solution, cupric chloride solution, ammonium persulfate aqueous solution and the like are preferable. By using these, only the electroless copper plating layer can be selectively etched after the resist is peeled off, and a circuit having excellent electrical reliability can be manufactured.

  A multilayer printed wiring board excellent in electrical reliability and signal response can be produced by newly laminating the insulating layer 3 with a carrier layer on the conductor circuit 11 thus completed and repeating the above steps. is there. If the core substrate is a double-sided circuit board, a double-sided multilayer printed wiring board can be produced.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this.

<Example 1>
25 parts by weight of novolak type cyanate resin (Lonza Japan Co., Ltd., Primaset PT-30, weight average molecular weight of about 700), biphenyldimethylene type epoxy resin (Nippon Kayaku Co., Ltd., NC-3000, epoxy equivalent 275, weight) (Average molecular weight 2000) 24.7 parts by weight, a copolymer of phenoxy resin / biphenyl epoxy resin and bisphenol S epoxy resin, the terminal part having an epoxy group (manufactured by Japan Epoxy Resin Co., Ltd., YX-8100H30 , 10 parts by weight of a weight average molecular weight of 30000) and 0.1 parts by weight of an imidazole compound (manufactured by Shikoku Kasei Kogyo Co., Ltd., Curesol 1B2PZ (1-benzyl-2-phenylimidazole)) were dissolved and dispersed in methyl ethyl ketone. Furthermore, 40 parts by weight of inorganic filler / spherical fused silica (manufactured by Admatechs Co., Ltd., SO-25R, average particle size 0.5 μm) and coupling agent / epoxysilane coupling agent (GE Toshiba Silicone Co., Ltd., A- 187) 0.2 part by weight was added and stirred for 10 minutes using a high-speed stirrer to prepare a resin varnish having a solid content of 50% by weight.

  The resin varnish obtained above was applied to one side of a 25 μm thick PET (polyethylene terephthalate) film with a release agent using a comma coater so that the thickness of the insulating film after drying was 60 μm. This was dried for 10 minutes with a drying apparatus at 160 ° C. to produce an insulating layer with a carrier layer.

This insulating layer with a carrier layer is superimposed on a double-sided substrate to be an inner layer circuit with the resin side of the insulating layer with a carrier layer facing inside, and this is laminated at a temperature of 100 ° C. and a pressure of 1 MPa using a vacuum pressurizing laminator device. Vacuum heating and pressure molding was performed, and then heat curing was performed at 170 ° C. for 60 minutes with a hot air drying apparatus to obtain a laminate. The degree of cure of the insulating layer resin of the laminate measured by DSC was 85%.
In addition, the following were used as the inner layer circuit board.
-Insulating layer: halogen-free, core substrate, thickness 0.4mm
Conductor layer: copper foil thickness 18 μm, L / S = 120/180 μm, clearance holes 1 mmφ, 3 mmφ, slit 2 mm

  A hole (via hole) was formed in the insulating layer portion with a carrier layer of the laminate by a carbon dioxide gas laser. At this time, using a carbon dioxide laser processing machine (Mitsubishi Electric Co., Ltd., ML605GTX3-5100U2), a hole of 60 μm was drilled by 0.8 mJ, 3 shots, direct method.

  The laminated body obtained above is immersed in a swelling solution (manufactured by Atotech Japan Co., Ltd., Swelling Dip Securigant P500) at 70 ° C. for 10 minutes with the carrier layer, and further an 80 ° C. potassium permanganate aqueous solution ( After being immersed in Atotech Japan Co., Ltd., Concentrate Compact CP) for 20 minutes, it was neutralized and desmeared.

  After peeling the carrier layer from the insulating layer of the laminate subjected to the above treatment, the surface of the insulating layer was modified by ultraviolet treatment. The ultraviolet treatment was performed with an ultraviolet cleaning and reforming apparatus (PM1108B-1 manufactured by Sen Special Light Source Co., Ltd.) with an irradiation distance of 50 mm and an irradiation time of 15 minutes.

  This was subjected to degreasing, catalyst application, and activation steps, and then an electroless copper plating layer of about 0.2 μm was formed. Then, a 25 μm thick UV-sensitive dry film (AQ-2558, manufactured by Asahi Kasei Co., Ltd.) was bonded by a hot roll laminator, and a chromium vapor deposition mask (stock) on which a pattern with a minimum line width / line spacing of 10/10 μm was drawn. Using a company topic company), the positions were aligned, exposed with an exposure device (UX-1100SM-AJN01, manufactured by USHIO INC.), And developed with an aqueous sodium carbonate solution to form a plating resist.

Next, electrolytic copper plating (Okuno Pharmaceutical Co., Ltd., 81-HL) was performed at 3 A / dm ² for 30 minutes using the electroless copper plating layer as an electrode to form a copper wiring having a thickness of about 20 μm. Subsequently, the plating resist was peeled off using a peeling machine. As the chemical solution, a monoethanolamine solution (R-100, manufactured by Mitsubishi Gas Chemical Co., Inc.) was used.

  Next, the electroless copper plating layer is treated with a mixed solution of hydrogen peroxide and sulfuric acid (manufactured by Sugawara Densan Co., Ltd., SAC-702M, SAC-701R35) to remove the etching and ensure insulation between the wirings. did. Next, the insulating resin layer was finally cured at a temperature of 200 ° C. for 60 minutes, and finally a solder resist (manufactured by Taiyo Ink Manufacturing Co., Ltd., PSR4000 / AUS308) was formed on the circuit surface to obtain a four-layer printed wiring board.

<Example 2>
A four-layer printed wiring board was produced in the same manner as in Example 1 except that the ultraviolet ray treatment was carried out with an ultraviolet ray irradiation for 30 minutes.

<Example 3>
A 4-layer printed wiring board was produced in the same manner as in Example 1 except that the carrier PET (polyethylene terephthalate) film was changed to a PEN (polyethylene naphthalate) film.

<Comparative Example 1>
After peeling the carrier layer of the laminate produced through the same lamination process as in Example 1, a hole (via hole) was formed in the insulating layer with a carbon dioxide gas laser, and then desmear treatment was performed without ultraviolet irradiation. A 4-layer printed wiring board was produced in the same manner as in Example 1 except that.

<Comparative example 2>
Example 1 except that holes (via holes) were formed by a carbon dioxide laser in the insulating layer with a carrier layer laminated on the laminate, and then the carrier layer was peeled off from the laminate, and desmear treatment was performed without ultraviolet irradiation. In the same manner, a four-layer printed wiring board was produced.

  The following evaluation was performed about the multilayer wiring board obtained by each Example and the comparative example. The evaluation items are shown together with the contents. The obtained results are shown in Table 1.

1. Evaluation of fine wiring formability Whether or not a pattern with a wiring pitch of 10 μm (L / S = 10/10) can be formed was determined by appearance inspection. Each code is as follows.
◯: There was no etching residue, short circuit, unevenness, defect, etc., and it was possible to form a wiring with L / S = 10/10.
X: Presence or absence of etching residue, short circuit, unevenness, defect, etc., and L / S = 10/10 wiring formation was impossible.

2. Insulating layer / plating adhesion evaluation In a four-layer substrate after forming an electrolytically plated copper layer and annealing at 200 ° C. for 60 minutes, a 90-degree peel test between the insulating layer and the plated copper was measured based on JIS C-6481. did. Each code is as follows.
A: The peel strength was 0.6 kN / m or more.
A: The peel strength was 0.4 kN / m or more and less than 0.6 kN / m.
Δ: The peel strength was 0.2 kN / m or more and less than 0.4 kN / m.
X: The peel strength was less than 0.2 kN / m.

3. Insulation reliability evaluation (PCBT)
The insulation reliability is between the conductors after being left for 100 hours using a 4-layer printed wiring board with a voltage of DC 5 V and a wiring pitch of 10 μm (L / S = 10/10) in an atmosphere of a temperature of 100 ° C. and a humidity of 85%. The insulation resistance value was evaluated by the digital insulation resistance value. Each code is as follows.
A: The insulation resistance value was 10 ⁹ Ω or more.
A: The insulation resistance value was 10 ⁸ Ω or more and less than 10 ⁹ Ω.
Δ: The insulation resistance value was 10 ⁷ Ω or more and less than 10 ⁸ Ω.
X: The insulation resistance value was less than 10 ⁷ Ω.

4). Signal Responsiveness Evaluation The signal responsiveness was evaluated by arithmetic surface roughness (Ra) of the insulating layer surface after UV treatment and after desmear treatment. Arithmetic surface roughness (Ra) was measured based on JIS B-601 using a scanning probe microscope (SPM-9600, manufactured by Shimadzu Corporation). Each code is as follows.
A: Less than 0.05 μm.
○: 0.05 μm or more and less than 0.10 μm.
(Triangle | delta): It was 0.10 micrometer or more and less than 0.30 micrometer.
X: It was 0.30 micrometer or more.

As is apparent from Table 1, Examples 1 to 3 were capable of forming a pattern with a wiring pitch of 20 μm, and were excellent in insulation reliability and signal response.
Moreover, Examples 1-3 were excellent also in the adhesiveness of an insulating layer and plated copper.

FIG. 1 is a cross-sectional view showing an example of a method for producing a multilayer printed wiring board according to the present invention. FIG. 2 is a cross-sectional view showing an example of a method for producing a multilayer printed wiring board according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate 2 Inner layer circuit 3 Insulating layer with carrier layer 31 Insulating layer 32 Carrier layer 4 Laminate 5 Hole 6 Laser 61 Energy beam 8 Electroless plating layer 9 Resist 10 Electrolytic plating layer 11 Conductor circuit

Claims (5)

A method for producing a multilayer printed wiring board, wherein an insulating layer made of a resin composition containing a thermosetting resin is laminated on at least one surface side of a substrate, wherein the carrier layer is formed on at least one surface side of the substrate A laminating step of laminating the attached insulating layer while heating it to obtain a laminated body, irradiating a predetermined portion of the laminated body with a laser to form a hole penetrating the carrier layer and the insulating layer, and the hole a desmear step of desmearing the inner surface of the, after the desmear process, possess a separation step of separating the carrier layer from the laminate,
Before the peeling step, the surface of the insulating layer has an irradiation step of modifying the surface of the insulating layer by irradiating energy rays through a carrier layer,
The method for producing a multilayer printed wiring board , wherein an arithmetic surface roughness (Ra) of the surface of the insulating layer after the irradiation step is 0.1 μm or less The method for producing a multilayer printed wiring board according to claim 1, wherein the insulating layer with a carrier layer has a release layer between the carrier layer and the insulating layer. The carrier layer, a method for manufacturing a multilayer printed wiring board according to claim 1 or 2 which is a polyester film. The thermosetting resin is an epoxy resin, a phenolic resin, the production of multilayer printed wiring board according to any one of 3 claims 1 is intended to include one or more resins selected from among cyanate resins and benzocyclobutene resins Method. The method for producing a multilayer printed wiring board according to any one of claims 1 to 4 , wherein the energy rays are ultraviolet rays.

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