CN102308679A

CN102308679A - Method of manufacturing multi-layered printed circuit board

Info

Publication number: CN102308679A
Application number: CN2011800009674A
Authority: CN
Inventors: 松田文彦
Original assignee: Nippon Mektron KK
Current assignee: Nippon Mektron KK
Priority date: 2010-02-08
Filing date: 2011-01-25
Publication date: 2012-01-04
Anticipated expiration: 2031-01-25
Also published as: JP5485299B2; TW201146123A; WO2011096293A1; JPWO2011096293A1; CN102308679B; TWI487451B

Abstract

Disclosed is a method of manufacturing build-up type multi-layer printed circuit boards having a stacked via structure allowing high-density component mounting. After forming a plated through via hole (9) and a plated via hole with a bottom (10) in a dual-side copper-clad laminate board, the copper foil on both sides of the dual-side copper-clad laminate board is patterned, resulting in a substrate with dual-side flexibility. Two cover lays (16) are prepared and laminated upon both sides of the substrate with dual-side flexibility. The laminating process is carried out under the following conditions: the interior of the plated through via hole (9) is completely filled with an adhesive agent derived by melting an adhesive agent layer (15) of the cover lay (16); and an air void (15a) may be allowed to occur, such that the interior of the plated via hole with the bottom (10) cannot be filled with the adhesive agent. After adhering a single-side copper-clad laminate board (20) to an insulator film (14) with an adhesive agent layer (22), laser working is used to remove the adhesive agent, and eliminate the air void (15a), within the plated via hole with the bottom (10), forming a step via hole such that the plated via hole with the bottom (10) becomes a lower hole.

Description

The manufacturing approach of multilayer printed-wiring board

Technical field

The present invention relates to the manufacturing approach of multilayer printed-wiring board, relate more specifically to increase the manufacturing approach of the multilayer printed-wiring board of layer (build up) type.

Background technology

In recent years, as the portable data assistance with portable phone etc. was representative, the miniaturization of electronic equipment and multifunction were in continuous development.Therefore, constantly surging to the requirement of the densification of the printed wiring board that in electronic equipment, uses.

Therefore, in order electronic unit to be installed to high-density, actively the multilayer flexible printed wiring plate that increases stratotype is researched and developed (for example with reference to patent documentation 1) at printed wiring board.This increase the stratotype multilayer flexible printed wiring plate with two sides flexible printing wiring board or multilayer flexible printed wiring plate as core substrate, be formed with the accumulation horizon (build up layer) about 1 ~ 2 layer at the two sides or the single face of this core substrate.Increase in the stratotype multilayer flexible printed wiring plate at this,, be provided with that inwall to via hole (hole is used in conducting) that die bed is arranged applies electroplating processes and the plating via hole that obtains interlayer conduction in order to be electrically connected the core substrate of accumulation horizon and internal layer.

, deepen, produce following problem along with this has the via hole (via hole) of die bed.At first, because each structural elements of printed wiring board carries out thermal expansion, electroplate via hole and be destroyed easily.In addition, forming when electroplating epithelium at the inwall of the via hole that die bed is arranged, because electroplate liquid is trapped in the bottom of via hole easily, so can not obtain desirable electroplating thickness in order to obtain interlayer conduction.Because such reason has the via hole of die bed to become dark more, be difficult to guarantee the electric reliability of via hole wiring more.

As the countermeasure of this problem, consider to form fully thick plating epithelium at the inwall of the via hole that die bed is arranged., when the thickness of the plating epithelium that forms at the inwall of the via hole that die bed is arranged increases, be difficult to avoid thickness also to become big with its conductor layer that on accumulation horizon, forms accordingly.Outer field circuit pattern is to form through the conductor layer on the accumulation horizon is carried out wet etching according to desirable pattern.Therefore, the thickness increase along with conductor layer is difficult to the conductor layer on the accumulation horizon is processed imperceptibly.As a result, can not form fine pattern, be difficult on accumulation horizon, install to high-density electronic unit as outer field circuit pattern.

As stated, increase in the stratotype multilayer flexible printed wiring plate, have the problem of the requirement be difficult to satisfy high-density installation existing.

, in increasing the multilayer flexible printed wiring plate of stratotype, from the viewpoint of the raising of densification and design freedom, what special demands had so-called lamination hole (stack via) structure increases the stratotype multilayer flexible printed wiring plate.Here, the lamination pore structure refer to core substrate by electroplating on the interlayer connecting portion that via hole constitutes, the overlapping interlayer connecting portion that constitutes by the plating via hole of accumulation horizon and the structure that disposes.

Can cheap and stably make have lamination pore structure that can high-density installation multilayer printed-wiring board by expectation consumingly.

Always, the method (with reference to patent documentation 2, patent documentation 3 and patent documentation 4) that once forms the via hole (step via hole) of so-called ladder via hole (step via) structure through laser processing is disclosed.According to disclosed method in these documents, can form the ladder via structure expeditiously., in the method, be used for electroplating normally once to concentrate and carrying out to electroplate cathode copper that epithelium covers the inwall of ladder via hole.The tendency that therefore, the plating epithelium attenuation that the sidewall in the following hole (path side) at the ladder via hole forms is arranged.Thus, the situation that has the reliability be difficult to guarantee that fully interlayer connects.

Then, use Fig. 3 that the manufacturing approach that increases stratotype multilayer printed-wiring board prior art, that have the lamination pore structure at length is described.Fig. 3 is the process profile that is used to explain the manufacturing approach that increases the stratotype multilayer printed-wiring board with lamination pore structure.

At first, prepare to have the pliability insulating substrate 101 (for example 25 μ m are thick) of polyimides etc. and at the Copper Foil 102 on its two sides and the two sides copper clad laminate 104 of Copper Foil 103 (all for example being that 8 μ m are thick).

Then, as can knowing from Fig. 3 (1), to this two sides copper clad laminate 104, forming through laser processing has an end via hole 105 as the via hole that die bed is arranged.In this bottom that end via hole 105 is arranged, exposing has Copper Foil 103.

Afterwards, through to Copper Foil 102,103 and have end via hole 105 to apply conductionization processing and metallide afterwards to handle, on Copper Foil 102,103 and have the inwall of end via hole 105 to form the metallide epithelium.The thickness of this metallide epithelium is set as the needed value of connection reliability (for example about 15 μ m) in order to ensure the via hole wiring.Through operation so far, form as the interlayer conduction portion that die bed is arranged that the Copper Foil 102 of pliability insulating substrate 101 and Copper Foil 103 are electrically connected, be electroplate with end via hole 106.

Then, as can knowing, Copper Foil of pliability insulating substrate 101 102 and Copper Foil 103 pattern are according to the rules carried out etching, form circuit pattern (internal layer circuit pattern) through photo-fabrication (photofabrication) from Fig. 3 (1).In more detail, a series of operation through being made up of peeling off of the etching of the forming of resist layer, exposure, development, Copper Foil and resist layer etc. forms circuit pattern on the two sides of pliability insulating substrate 101.

Then, can know, prepare on the dielectric film 107 (for example 12 μ m are thick) of polyimide film etc., to have the cover layer 109 of adhesive layer 108 from Fig. 3 (1).Adhesive layer 108 for example is made up of the binding agent of acrylic acid, epoxy etc.Then, use vacuum laminator etc., carry out in the lamination that is formed with applying cover layer 109 on the pliability insulating substrate 101 of circuit pattern.The thickness of this adhesive layer 108 is set as the thickness (for example 25 μ m) that can complete filling be electroplate with the inwall of end via hole 106 with binding agent.Through operation so far, obtain the two sides core substrate 110 shown in Fig. 3 (1).

Then, shown in Fig. 3 (2), prepare to have the single face copper clad laminate 111 of Copper Foil (for example thickness 12 μ m) at the single face of pliability insulating substrate (the for example thick polyimides of 25 μ m).Through above-mentioned photo-fabrication, form peristome in the part of the regulation of the Copper Foil of this single face copper clad laminate 111.Make this Copper Foil become the deposited shape mask (being also referred to as metal mask) that the laser shading is used with peristome.The opening that forms at Copper Foil is used for removing through laser processing the resin of the pliability insulating substrate that exposes in the bottom surface of this opening etc., forms via hole.

Then; Can know from Fig. 3 (2); Core substrate 110 is used to increase the binding agent of layer on the two sides, and the single face copper clad laminate 111,111 that will have deposited shape mask (conformal mask) is via adhesive layer 112, the 112 range upon range of respectively surface and the back sides that are bonded to two sides core substrate 110.

Then, can know, carry out laser processing, form ladder via hole 113A and via

hole

113B, 113C through the deposited shape mask that uses single face copper clad laminate 111 from Fig. 3 (2).

Then, can know from Fig. 3 (3), through on the Copper Foil to single face copper clad laminate 111, the inwall of the inwall of ladder via hole 113A and via

hole

113B, 113C applies the conductionization processing and metallide is afterwards handled, thereby form the metallide epithelium.The thickness of this metallide epithelium for example is made as about 25 ~ 30 μ m in order to ensure the reliability that interlayer connects.Thus, the plating that forms for the interlayer conduction that obtains core substrate and accumulation horizon increases a layer via

hole

114A, 114B, 114C.It is the hole that has applied electroplating processes at the inwall of ladder via hole 113A that plating increases layer via hole 114A; It is the hole that has applied electroplating processes at the inwall with ladder via hole 113A via hole 113B in opposite directions that plating increases layer via hole 114B, and it is the hole that has applied electroplating processes at the inwall of via hole 113C that plating increases layer via hole 114C.

Then, can know, the Copper Foil pattern according to the rules of single face copper clad laminate 111,111 carried out etching, form external circuit pattern 115,115 through using photo-fabrication from Fig. 3 (3).Afterwards,, form photosensitive solder resist agent (Photo solder resist) layer (not shown) corresponding to needs, the surface treatment that applies that scolder is electroplated, nickel is electroplated, gold is electroplated etc. at the terminal of circuit pattern, the stamping-out through utilizing metal pattern etc. carries out sharp processing.

Through above operation, what obtain to have the lamination pore structure increases stratotype multilayer printed-wiring board 116.Can know from Fig. 3 (3), electroplate increase layer via hole 114A the two sides of internal layer core substrate 110 be electroplate with end via hole 106 directly over form, be electroplate with end via hole 106 and increase layer via hole 114A with plating and form a lamination pore structure.In increasing stratotype multilayer printed-wiring board 116, the surface of two sides core substrate 110 is connected with the interlayer at the back side through being electroplate with end via hole 106 carries out.

Have, can know from Fig. 3 (3), increase stratotype multilayer printed-wiring board 116 and have: core substrate 110 is range upon range of on the two sides has the parts installation portion 116a of accumulation horizon and a 116b of flexible cable portion that extends from this parts installation portion 116b.The 116b of this flexible cable portion is the part that the two sides core substrate 110 of accumulation horizon is not set.

In above-mentioned operation, being electroplate with end via hole 106 inside needs bonded dose of complete filling., be electroplate with end via hole 106, apply electroplating processes with inwall and the perforation via hole that forms is compared, be difficult to filling adhesive at the via hole that connects two sides copper clad laminate 104.This is because electroplating the perforation via hole can fill from 2 directions at the surface and the back side, with respect to this, has the end to electroplate via hole and only can fill from 1 direction.Therefore, the thickness of adhesive layer 108 is compared with the situation that the interlayer that carries out two sides core substrate 110 with plating perforation via hole is connected, and is difficult to avoid thickening.Thus, increasing layer via hole 113 deepens.So, as above-mentioned, be used to guarantee that the electroplating thickness of the reliability that interlayer connects becomes big.For example, when the formation plating increases a layer via

hole

114A, 114B, 114C, need be used to form the metallide of the plating epithelium about 25 ~ 30 μ m as stated.Suppose to carry out on the Copper Foil (12 μ m are thick) at single face copper clad laminate 111 under the situation of metallide of such degree, the thickness of the conductor layer on the single face copper clad laminate 111 (Copper Foil+metallide epithelium) is 37 ~ 42 μ m altogether.Because the composition of conductor layer carries out through wet etching, be the fine circuit pattern about 100 μ m so be difficult to high finished product rate ground formation circuit spacing.

As stated, in the prior art, existence can not be made the problem that increases the stratotype multilayer printed-wiring board of the requirement of satisfying high-density installation.Have, this problem also is same in the multilayer printed-wiring board that does not have flexible cable 116b certainly again.

The prior art document

Patent documentation

Patent documentation 1: TOHKEMY 2004-200260 communique;

Patent documentation 2: TOHKEMY 2008-235801 communique;

Patent documentation 3: TOHKEMY 2008-288434 communique;

Patent documentation 4: TOHKEMY 2009-026912 communique.

Summary of the invention

The problem that invention will solve

The present invention is in order to solve owing to being difficult to form fine outer circuit pattern; But so can not obtain the problems referred to above of the multilayer printed-wiring board of high-density installation, its purpose is to provide a kind of manufacturing approach that increases the stratotype multilayer printed-wiring board with lamination pore structure of ability high-density installation.

Be used to solve the scheme of problem

According to a mode of the present invention, a kind of manufacturing approach of multilayer printed-wiring board is provided, it is characterized in that,

The conductive film layer pressing plate is covered on two sides to having the 1st conducting film and the 2nd conducting film respectively at the surface and the back side, and form the plating that said the 1st conducting film and said the 2nd conducting film are electrically connected and connect via hole and be electroplate with end via hole,

Through said the 1st conducting film and said the 2nd conducting film pattern are according to the rules carried out etching, thereby make two sides flexible base plate with internal layer circuit pattern,

Preparation has dielectric film and is formed with the cover layer of adhesive layer at the single face of said dielectric film,

Under following condition; Promptly connect the inside of via hole and allow and produce the said inside that is electroplate with end via hole not by under the condition in the space of said binding agent filling through the said plating of the binding agent complete filling after the said tectal said adhesive layer fusion; Carry out said tectal lamination is pasted on the two sides of said two sides flexible base plate; Make the two sides core substrate thus

The said at least opening surface side that is electroplate with end via hole of core substrate on said two sides, range upon range of bonding have the accumulation horizon of the 3rd conducting film that forms at single face,

Through laser processing, remove the said inner said binding agent of end via hole that is electroplate with, said space is disappeared, thus, expose the said end via hole that is electroplate with in the bottom, form the said end via hole that is electroplate with and become the ladder via hole in hole down,

Inwall through to said the 3rd conducting film and said ladder via hole applies electroplating processes, and form the plating that said the 3rd conducting film and said internal layer circuit pattern are electrically connected and increase a layer via hole,

Said the 3rd conducting film pattern according to the rules through having implemented electroplating processes carries out etching, forms the outer circuit pattern.

The effect of invention

According to above-mentioned characteristic, the present invention obtains following effect.

Have the increasing in the stratotype multilayer printed-wiring board of lamination pore structure in an embodiment of the invention; The lamination pore structure is increased layer via hole and is constituted by the surface of two sides flexible base plate and the back side are electrically connected be electroplate with end via hole and be electroplate with the plating of disposing on the end via hole at this.This plating increases layer via hole outer circuit pattern and internal layer circuit pattern is electrically connected, and is the inwall of ladder via hole that has end via hole to make the hole of minor diameter that the flexible base plate on the two sides forms is formed with the hole of electroplating epithelium.Thus, formation increases the ladder via structure that layer via hole constitutes by the plating that is electroplate with end via hole and form above that.

Through such characteristic, according to an embodiment of the invention, when cover layer is carried out lamination, need be to the inside complete filling binding agent that is electroplate with end via hole of flexible base plate formation on the two sides.Its reason is, when forming said ladder via hole, the binding agent that is electroplate with in the end via hole is removed.Therefore, can the scope of filling adhesive in to the perforation via hole of two sides flexible base plate in, can reduce the thickness of adhesive layer as much as possible.

As a result, compared with prior art, the ladder via hole is shoaled.Thus, increasing layer via hole and carrying out metallide when handling in order to form to electroplate, the raising of the easy property of electro-deposition, and the thermal expansion of structural elements increases influence from layer via hole to plating is alleviated.

Therefore,, rate of finished products is improved, can reduce the needed electroplating thickness of connection reliability as much as possible in order to ensure the via hole wiring according to the present invention.Therefore, according to the present invention, can make the outer circuit pattern that forms accumulation horizon finer.

And then, according to the present invention, form to electroplate when increasing layer via hole, being electroplate with of flexible base plate also forms the metallide epithelium on the end via hole on the two sides.Thus, result from asymmetrical shape, compare the end via hole that is electroplate with that thermal stress concentrates easily and be reinforced with electroplate connecting via hole, connection reliability is improved.

And then, as stated because be electroplate with end via hole and be reinforced, so the degree that this electroplating thickness that is electroplate with end via hole is thinned to can guarantee to electroplate the connection reliability that connects via hole.As a result, the needed time of electroplating work procedure is shortened, and can reduce cost.In addition, can make the internal layer circuit fine patternsization that flexible base plate forms on the two sides.

As stated, according to the present invention, provide cheap and stably make can high-density installation the method that increases the stratotype multilayer printed-wiring board with lamination pore structure.

Description of drawings

Figure 1A is the process profile of the manufacturing approach that increases the stratotype multilayer printed-wiring board that is used to explain that execution mode of the present invention relates to.

Figure 1B is used for then Figure 1A, and the process profile of the manufacturing approach that increases the stratotype multilayer printed-wiring board that execution mode of the present invention relates to is described.

Fig. 1 C is used for then Figure 1B, and the process profile of the manufacturing approach that increases the stratotype multilayer printed-wiring board that execution mode of the present invention relates to is described.

Fig. 2 is the profile that increases the stratotype multilayer printed-wiring board that execution mode of the present invention relates to.

Fig. 3 is prior art, have the process profile of the manufacturing approach that increases the stratotype multilayer printed-wiring board of lamination pore structure.

Embodiment

Below, on one side with reference to accompanying drawing, the manufacturing approach that increases the stratotype multilayer printed-wiring board with lamination pore structure that relates to execution mode of the present invention on one side describes.

Have again, give prosign, omit detailed explanation structural element with same function.In addition, accompanying drawing is schematically, and the characteristic that relates to execution mode is that the center is represented, the ratio of the relation of thickness and planar dimension, the thickness of each layer etc. are different with reality.

At first, use Figure 1A to Fig. 1 C and Fig. 2, the manufacturing approach that increases stratotype multilayer printed-wiring board 32 with lamination pore structure that relates to execution mode of the present invention describes.

Figure 1A to Fig. 1 C is used to explain that this increases the process profile of the manufacturing approach of stratotype multilayer printed-wiring board 32.Fig. 2 is the profile that increases stratotype multilayer printed-wiring board 32 that this execution mode relates to.

At first, can know, prepare to have respectively the double-sided copper-clad laminated sheet 4 of Copper Foil 2 and Copper Foil 3 (the 1st conducting film and the 2nd conducting film) on the two sides of pliability insulating substrate 1 (the for example thick polyimides of 25 μ m) from Figure 1A (1).The thickness of Copper Foil 2 and Copper Foil 3 for example all is 5 μ m.

Then, this two sides copper clad laminate 4 is used laser processing method or resin etching method etc., form the perforation via hole 5 that connects two sides copper clad laminate 4 and end via hole 6 is arranged.This has end via hole 6 can know from Figure 1A (1), is to expose the via hole that die bed is arranged that Copper Foil 3 is arranged in the bottom surface.Have, this perforation via hole 5 all for example is diameter 70 μ m with the processing diameter of end via hole 6 is arranged again.

In this operation, use under the situation of laser processing method, can select 2 following methods.The 1st method is to be called as the method for applying shape laser (conformal laser) processing method.In the method, at the peristome of Copper Foil 2, the 3 settings diameter identical, form and apply the shape mask with the path aperture.Afterwards, to applying shape mask irradiating laser, remove the insulating resin that exposes at peristome.The 2nd method is the method that is called as direct laser processing method.In the method, do not form and apply the shape mask, and to direct irradiation laser on the Copper Foil, remove Copper Foil and under insulating resin.In this execution mode, do not select to utilize the deposited shape laser processing method of etching work procedure of the Copper Foil of photo-fabrication, and consider productivity, select to utilize the direct laser processing method of carbon dioxide laser.

Before carrying out this direct laser processing method, the

Copper Foil

2,3 of two sides copper clad laminate 4 is implemented surface treatment.That is, making the copper-clad surface of laser radiation is the roughened of low roughness.Thus, using carbon dioxide laser (wavelength: about 9.8 μ m) when carrying out laser processing, the absorption of the laser of

Copper Foil

2,3 is stably improved.In this execution mode, the MULTIBOND150 of the Japanese Macdermid of use Co., Ltd. in this roughened.Thus, can guarantee to electroplate the connecting airtight property of epithelium 7, and the absorption of the carbon dioxide laser in the surface of Copper Foil is improved with the cathode copper that forms in the operation of back.In fact before and after surface-treated, confirmed that the absorptivity of carbon dioxide laser brings up to about 30% from about 20%.

Have, in this execution mode, processing simultaneously connects via hole 5 and end via hole 6 is arranged again.Therefore, carry out above-mentioned roughened, can make the handling ease of Copper Foil 2 through surface to Copper Foil 2.And, preferably be formed with the end during via hole 6 not connecting the mode of Copper Foil 3, making copper-clad surface as the back treatment of Copper Foil 3 is the processing of low roughness, and the absorption of laser is reduced.But, form expeditiously under the situation that connects via hole 5 in hope, preferably carry out roughened as the back treatment of Copper Foil 3.

The

Copper Foil

2,3 of two sides copper clad laminate 4 is thin more, and the perforation of

Copper Foil

2,3 takes place when laser processing more easily.Therefore, be under the thin situation below the 10 μ m at the thickness of as this execution mode, hoping Copper Foil, for the formation that makes end via hole 6 is easy, implement roughened hardly as back treatment, preferably use the Copper Foil 3 of low roughness.

Here, the mode to laser processing at length describes.At first, describe to the situation that is processed with end via hole 6.When processing Copper Foil 2, improve the energy of emitted laser (being made as power P) each time.And, preferably accomplish the processing of Copper Foil 2 with 1 emission.Afterwards, the resin to pliability insulating substrate 1 till exposing to Copper Foil 3 adds man-hour, makes each time that the energy of emitted laser is reduced to (1/2) P ~ (1/3) P, accomplishes the processing of resin with 2 ~ 3 emissions.Then, narrate to the situation that connects via hole 5.In this case, use the energy of emitted laser each time to be made as the laser of above-mentioned power P, the Copper Foil and the resin on two sides are processed.Carry out 3 ~ 4 emissions continuously and shine, accomplish the processing that connects via hole 5.

And then using under the situation of thin copper foil, for the formation that makes end via hole 6 becomes easily, making the back side (face that joins with base material) of the Copper Foil 3 that becomes the bottom that end via hole 6 is arranged is low roughness.And, the back side of Copper Foil 2 (face that joins with base material) carried out roughened.Then, the surface from Copper Foil 3 processes formation perforation via hole 5.According to this method, the formation of end via hole 6 is become easily, and can form the perforation via hole expeditiously.In addition,, carry out laser processing, form and connect via hole 5 and also can from 2 directions on the surface of the surface of Copper Foil 2 and Copper Foil 3 as other method.In this case, because roughened is carried out on the surface of

Copper Foil

2,3, so have following advantage, i.e. processing from any direction is all easy, and need not consider the state (height of roughness) of the back treatment of Copper Foil.

Then, in order to remove, carry out Cement Composite Treated by Plasma and wet etching (dirty removal processing) form connecting via hole 5 and dirty (gum residue) that have the end to produce during via hole 6.For connecting via hole 5 and having optimal conditions end via hole 6, that this plasma is handled roughly the same.On the other hand, to the wet etching that has used sodium peroxydisulfate etc., different at optimal conditions between the two.That is, for through hole 5, wet etching needs hardly.On the contrary, through etching,

Copper Foil

2,3 is retreated, and exists the conduction processing to the back to cause dysgenic situation.On the other hand, for end via hole 6 is arranged, the metal not of the same race for the nickel at the back side of removing the Copper Foil 3 that back treatment causes, chromium etc. needs the etching of 1 ~ 2 μ m.Consideration is preferably accomplished processing with few etch quantity of trying one's best to the influence that connects via hole 5.In this execution mode, carry out the etching of 1 μ m.

Then, can know from Figure 1A (2), through on the

Copper Foil

2,3, connect the inwall of via hole 5 and have the inwall of end via hole 6 to apply conductionization processing and cathode copper electroplating processes afterwards, thereby formation cathode copper plating epithelium 7 (about 8 μ m are thick).Thus, the copper electrodeposited coating, the plating that form on the

Copper Foil

2,3 connect via hole 9 and are electroplate with end via hole 10.It is through interlayer conduction roads that this plating connects via hole 9, and being electroplate with end via hole 10 is interlayer conduction roads that die bed is arranged.These are electroplated via holes and all the Copper Foil 2 on the surface of pliability insulating substrate 1, the Copper Foil 3 at the back side are electrically connected.

Have, it is different in connecting via hole 5 and end via hole 6 is arranged that the liquid of the treatment fluid in above-mentioned conduction treatment process and the cathode copper electroplating work procedure upgrades property again.That is there, have end via hole 6 to compare liquid renewal property with perforation via hole 5 to be poor.Therefore, carrying out operation basically under with the condition that can handle end via hole 6 flows.To the cathode copper electroplating work procedure, near the easy variation of the uniformly-coating property of the sidewall the bottom that end via hole 6 is arranged.Thus, the cathode copper electroplating processes preferably uses the electroplating bath of the copper sulphate that contains high concentration to carry out.

Then, can know, on copper electrodeposited

coating

8,8, form resist

layer

11,11 from Figure 1A (3).In the formation of this resist layer 11, use dry film photoresist.This dry film photoresist preferably uses electroplating the dry film photoresist that the both sides that connect via hole 9 and be electroplate with end via hole 10 can be covered the thickness (for example 20 μ m) of (tenting).Thus, can prevent that resist from getting into plating and connecting via hole 9 and be electroplate with in the end via hole 10, the peeling off of resist layer 11 that the back is carried out becomes easy.Have again, replace dry film photoresist, also can use aqueous resist or electro-deposition resist.

Then, can know, utilize photo-fabrication from Figure 1A (4); Exposure, development through resist layer 11; Pattern according to the rules carries out etching to resist layer 11, afterwards with composition resist layer 11 as mask, copper electrodeposited coating 8 and

Copper Foil

2,3 are carried out etching.Afterwards, peel off resist layer 11.Thus, form internal

layer circuit pattern

12A and 12B respectively at the surface and the back side of pliability insulating substrate 1.

Through operation so far, obtain the two sides flexible base plate 13 shown in Figure 1A (4).

Then, can know from Figure 1B (5), prepare cover layer 16, it has the dielectric film 14 (for example 12 μ m are thick) of polyimide film etc. and the adhesive layer 15 that forms at the single face of dielectric film 14.Adhesive layer 15 for example is made up of the binding agent of acrylic acid, epoxy etc.Then, use vacuum laminator etc., carry out the lamination of the two sides stickup cover layer 16 of flexible base plate 13 on the two sides.Thus, internal

layer circuit pattern

12A, 12B and plating perforation via hole 9 are filled through adhesive layer 15.

In this lamination, need not be electroplate with the inside of end via hole 10 with the binding agent complete filling.Promptly; Lamination is carried out under following condition; That is, electroplate to connect the inside of via hole 9, and allow and produce the space 15a that the binding agent after not bonded dose layer 15 fusion in inside that are electroplate with end via hole 10 is filled through the binding agent complete filling after adhesive layer 15 fusions of cover layer 16.Like this, as long as the thickness of the adhesive layer in this execution mode 15 can complete filling be electroplated perforation via hole 9, need not consider to be electroplate with the occupied state of end via hole 10 inside.Thus, but adhesive layer 15 electroplate to connect in the scope of via hole 9 thin as much as possible in complete filling.In this execution mode, the thickness of adhesive layer 15 is 15 μ m.Shown in Figure 1B (5), have in the situation that is electroplate with the end via hole 10 inner space 15a of generation., owing in the operation of back, remove the binding agent that is electroplate with in the end via hole 10 fully through laser processing, so this space 15a does not become problem.

In operation so far, shown in Figure 1B (5), acquisition becomes the two sides core substrate 17 of the core substrate of multilayer printed-wiring board.

Then, shown in Figure 1B (6), prepare to have the single face copper clad laminate 20 of the Copper Foil 18 (the 3rd conducting film) that for example 12 μ m are thick at the single face of pliability insulating substrate 19 (the for example thick polyimides of 25 μ m).And, through photo-fabrication, at the Copper Foil 18 formation peristome 18a of single face copper clad laminate 20.More specifically, on Copper Foil 18, form resist layer (not shown), this resist layer is carried out composition through exposure and development.Then, with composition resist layer as mask, Copper Foil 18 is carried out etching.Thus, form deposited shape mask 21.This peristome 18a is used for forming via hole at the resin that the operation of back is removed base material through laser processing.

Then, can know that be used to increase the binding agent of layer, the single face copper clad

laminate

20,20 that will be formed with deposited shape mask 21 is via adhesive layer 22, the 22 range upon range of two sides that are bonded to two sides core substrate 17 from Figure 1B (6).As the binding agent that here uses, the prepreg of preferred lazy flow, bonding sheet etc. flow out few material.Have again, after the single face copper clad laminate 20 that will have unprocessed Copper Foil 18 bonds to two sides core substrate 17 via adhesive layer 22, Copper Foil 18 pattern is according to the rules carried out etching, form deposited shape mask 21 and also can.

Then, can know, use deposited shape mask 21 to carry out laser processing, form ladder via hole 23 and via

hole

24A, 24B from Fig. 1 C (7).This ladder via hole 23 connects pliability insulating substrate 19, adhesive layer 22, dielectric film 14 and adhesive layer 15, exposes in the bottom to be electroplate with end via hole 10.In the operation of this laser processing, be electroplate with end via hole 10 inner resins and be removed entirely, space 15a disappears.Via

hole

24A, 24B connect pliability insulating substrate 19, adhesive layer 22, dielectric film 14 and adhesive layer 15, and exposing in its bottom has internal

layer circuit pattern

12A, 12B.

Have again,, also need remove the resin that is electroplate with end via hole 10 inside in order to form ladder via hole 23.Therefore, about the amount of the resin material that should remove, ladder via hole 23 is more than via hole 24A, 24B.Therefore, when the formation of ladder via hole 23, preferably increase the emitting times of laser processing, or make the pulse duration of laser elongated.As the laser that in this laser processing, uses, can select UV-YAG laser, carbon dioxide laser, excimer laser etc.

Then, can know from Fig. 1 C (8), through on the Copper Foil 18, the inwall of the inwall of ladder via hole 23 and via

hole

24A, 24B applies the conductionization processing and metallide is afterwards handled, thereby form metallide epithelium 25.Thus, the copper electrodeposited coating 26 and the plating that form on the Copper Foil 18 increase layer via

hole

27,28,29.These are electroplated via hole and all internal

layer circuit pattern

12A, 12B and Copper Foil 18 and copper electrodeposited coating 26 (the outer circuit pattern of afterwards stating 30) are electrically connected.It is the via holes that are formed with electrodeposited coating at the inwall of ladder via hole 23 that plating increases layer via hole 27.It is the via holes that are formed with electrodeposited coating at the inwall with ladder via hole 23 via hole 24A in opposite directions that plating increases layer via hole 28.It is the via holes that are formed with electrodeposited coating at the inwall of via hole 24B that plating increases layer via hole 29.

The thickness of this metallide epithelium 25 is made as in order to ensure the needed value of connection reliability.In this execution mode, compared with prior art reduced the thickness of adhesive layer 15, the thickness of metallide epithelium 25 is compared with prior art (for example about 25 ~ 30 μ m) thus, also can be thinned to about 15 μ m ~ 20 μ m.

Can know from Fig. 1 C (8),, accomplish being electroplate with to be formed with on the end via hole 10 and electroplate the lamination pore structure that increases layer via hole 27 through operation so far.

Then, can know, Copper Foil 18 and metallide epithelium 25 pattern according to the rules carried out etching, form outer circuit pattern 30 through using photo-fabrication from Fig. 2.Afterwards,, form photosensitive solder resist agent layer (not shown) corresponding to needs, the surface treatment that applies that scolder is electroplated, nickel is electroplated, gold is electroplated etc. at the terminal of circuit pattern, the stamping-out through utilizing metal pattern etc. carries out sharp processing.

Through above operation, as shown in Figure 2, obtain that this execution mode relates to have a lamination pore structure increase stratotype multilayer printed-wiring board 32.

Increase in the stratotype multilayer printed-wiring board 32 what this execution mode related to,, outer field single face copper clad

laminate

20,20 arranged via

adhesive layer

22,22 is range upon range of at the surface and the back side of the two sides core substrate 17 that becomes internal layer.This execution mode is not limited thereto, only on the two sides surface of core substrate 17, be the opening surface side that is electroplate with end via hole 10 of two sides core substrate 17, also can via adhesive layer 22 range upon range of outer field single face copper clad laminates 20.Thus, can obtain only to possess the multilayer printed-wiring board of accumulation horizon at single face.

Internal

layer circuit pattern

12A, 12B increase layer via

hole

27,28,29 through plating, are electrically connected with outer circuit pattern 30.

Have, the stratotype multilayer printed-wiring board 32 that increases that the manufacturing approach that relates to through this execution mode obtains has again: at the two sides core substrate 17 range upon range of parts mounting layer 32a that accumulation horizon 31 is arranged as the pliability printed wiring board; And on the two sides core substrate 17 does not have the 32b of flexible cable portion of layer stack lamination.That is, the 32b of flexible cable portion is the structure of extending from parts installation portion 32a.This execution mode is not limited thereto, and the multilayer printed-wiring board that manufacturing two sides core substrate 17 does not constitute flexible cable 32b also can.

In addition, in this execution mode, be illustrated to the manufacturing approach of flexible multi-layered printed wiring board, but the present invention is not limited thereto.

In addition; As laser processing method; Outside above-mentioned deposited shape laser processing method, direct laser processing method; Also have and on Copper Foil 18, form than after the big opening of the diameter in hole on the ladder via hole 23 the big window technique of the laser of the beam diameter that irradiation is identical with the diameter in the last hole of ladder via hole 23 etc.The laser processing method that can select is not limited to the method in the explanation of above-mentioned execution mode, used, can at random select to apply shape method, directly laser method and big window technique according to each operation.Have, under the situation of using direct laser method, as this execution mode, the thickness of preferred Copper Foil is below the 15 μ m again.

In addition; In this execution mode; Carry out in the face of cover layer 16 after thereby lamination makes two sides core substrate 17 at two of two sides flexible base plate 13, the core substrate 17 layer stack laminations on the two sides, but the present invention is not limited thereto; Replace cover layer 16 to use the single face copper clad laminate that has binding agent, two sides flexible base plate 13 directly is provided with accumulation horizon also can.In this case, make multilayer printed-wiring board as follows.At first, as above-mentioned, make be formed with electroplate connect via hole 9, be electroplate with end via hole 10 and internal layer circuit pattern 12A, the two sides flexible base plate 13 of 12B.Afterwards, the single face of preparing to have adhesive layer covers the conductive film layer pressing plate, the adhesive layer that it has insulating substrate, the conducting film (the 3rd conducting film) that forms on the surface of said insulating substrate, forms at the back side of said insulating substrate.The lamination that the single face that has adhesive layer covers the conductive film layer pressing plate is pasted on the two sides of then, carrying out the flexible base plate 13 on the two sides.This lamination is carried out under following condition; Promptly; The binding agent complete filling of covering through the single face that has adhesive layer after the adhesive layer fusion of conductive film layer pressing plate is electroplated the inside that connects via hole 9, and allows and produce the space that the binding agent after the not bonded dose of layer fusion in inside that is electroplate with end via hole 10 is filled.To the multilayer printed-wiring board of such acquisition, remove through laser processing and to be electroplate with the inner binding agent of end via hole 10, the space is disappeared, thus, expose in the bottom and to be electroplate with end via hole 10, form and be electroplate with end via hole 10 and become the ladder via hole in hole down.Afterwards, apply electroplating processes, form the plating that the 3rd conducting film and internal layer circuit pattern 12A are electrically connected and increase a layer via hole through inwall to the 3rd conducting film and ladder via hole.Then, carry out etching, form the outer circuit pattern, obtain to increase the multilayer printed-wiring board of stratotype through the 3rd conducting film pattern according to the rules that will implement electroplating processes.

As stated, two sides core substrate 17 have be used for internal layer circuit pattern 12A and internal layer circuit pattern 12B are electrically connected, electroplate and connect via hole 9 and be electroplate with end via hole 10.The lamination pore structure constitutes by being electroplate with end via hole 10 and increasing layer via hole 27 in this plating that is electroplate with on the end via hole 10 configuration.It is that the end via hole 10 that is electroplate with that the core substrate 17 on the two sides forms is made the hole that the inwall of ladder via hole 23 in the hole of minor diameter is formed with the metallide epithelium that this plating increases layer via hole 27.In addition, electroplate the interlayer conduction that connects via hole 10 employings only the carrying out surface and the back side of two sides core substrate 17, do not carry out the structure of outer circuit pattern 30 and the interlayer conduction of internal

layer circuit pattern

12A, 12B.

Through above-mentioned characteristic, obtain following effect according to this execution mode.

When cover layer 16 is carried out lamination, no longer need be electroplate with the inside of end via hole 10 with the binding agent complete filling.That is, the inside that is electroplate with end via hole 10 is the state of not exclusively filling with binding agent, exists space 15a also can.Therefore, in can the scope of complete filling binding agent, can reduce the thickness of the adhesive layer 15 of cover layer 16 as much as possible to the inside that electroplate to connect via hole 9.As a result, can make ladder via hole 23 more shallow (for example about 10 μ m) as much as possible, the easy property of the electro-deposition raising when the inwall of ladder via hole 23 and via hole 24A, 24B applies the metallide processing.And then, electroplate and to increase layer via hole the 27,28, the 29th, be difficult to receive the favourable structure of influence etc. of thermal expansion of the structure member of printed wiring board.The coefficient of thermal expansion of binding agent that in structural elements, particularly constitutes adhesive layer 15 is big, and therefore through making adhesive layer 15 attenuation, effect is big.Therefore, can reduce in order to ensure the raising of rate of finished products and the thickness of the needed metallide epithelium 15 of connection reliability.As a result, according to this execution mode, can form fine outer circuit pattern 30.

And then, according to this execution mode, form to electroplate when increasing layer via hole 27, also form metallide epithelium 26 on the end via hole 10 being electroplate with.Thus, result from asymmetrical shape, compare the end via hole 10 that is electroplate with that thermal stress concentrates easily and be reinforced with electroplate connecting via hole 9, connection reliability is improved.

And then, according to this execution mode, be reinforced, so can make the electroplating thickness (cathode copper is electroplated the thickness of epithelium 7) that is electroplate with end via hole 10 be thinned to the degree that can guarantee to electroplate the connection reliability that connects via hole 9 because be electroplate with end via hole 10.As a result, the needed time of electroplating work procedure is shortened, and can reduce cost.In addition, owing to cooperate the electroplating thickness that is electroplate with end via hole 10, also attenuation of copper electrodeposited coating 8 is so can make internal layer circuit pattern 12 miniaturizations of two sides core substrate 17.

Have again, in the explanation of execution mode, wiring pattern with electroplate epithelium and constitute by copper, but the present invention is not limited thereto, and for example is that other metals such as aluminium, silver also can.

Based on above-mentioned record, so long as those skilled in the art possibly can expect effect of appending of the present invention, various distortion, but mode of the present invention are not limited to above-mentioned execution mode.In the scope of the thought of the notion of the present invention that interior perhaps its coordinate that does not break away from the scope defined that is required by the present technique scheme is derived and purport, can carry out variously appending, changing and deletion partly.

Description of reference numerals

1,19,101 pliability insulating substrates;

2,3,18,102,103 Copper Foils;

4,104 two sides copper clad laminates;

5 connect via hole;

6,105 have end via hole;

7 cathode coppers are electroplated epithelium;

8,26 bronze medal electroplating films;

9 electroplate the perforation via hole;

10,106 be electroplate with end via hole;

11 resist layers

12A, 12B internal layer circuit pattern;

13 two sides flexible base plates;

104,107 dielectric films;

15,22,108,112 adhesive layers;

The 15a space;

16,109 cover layers;

17,110 two sides core substrates;

18 Copper Foils;

The 18a peristome;

20,111 single face copper clad laminates;

21 apply the shape mask;

23,113A ladder via hole;

24A, 24B, 113B, 113C via hole;

25 metallide epitheliums;

27,28,29,114A, 114B, 114C electroplate and increase a layer via hole;

30,115 outer circuit patterns;

31 increase a layer via hole;

32,116 increase the stratotype multilayer printed-wiring board;

32a, 16a parts installation portion;

32b, 116b flexible cable portion.

Claims

1. the manufacturing approach of a multilayer printed-wiring board is characterized in that,

Preparation has dielectric film and the cover layer of the adhesive layer that forms at the single face of said dielectric film,

2. the manufacturing approach of a multilayer printed-wiring board is characterized in that,

The single face that preparation has adhesive layer covers the conductive film layer pressing plate, the adhesive layer that it has insulating substrate, the 3rd conducting film that forms on the surface of said insulating substrate and forms at the back side of said insulating substrate,

Under following condition; Promptly connect the inside of via hole and allow and produce the said inside that is electroplate with end via hole not by under the condition in the space of said binding agent filling through the said plating of the binding agent complete filling after the said adhesive layer fusion; Carry out the lamination that the said single face that has adhesive layer covers the conductive film layer pressing plate is pasted on the two sides of said two sides flexible base plate

3. the manufacturing approach of multilayer printed-wiring board according to claim 1 and 2; It is characterized in that; Said laser processing is carried out through following method; That is, use said the 3rd conducting film is carried out etching and deposited shape laser processing method that the deposited shape mask that forms carries out, the direct laser processing method of said the 3rd conducting film direct irradiation laser; Perhaps the big opening of diameter in hole on said the 3rd conducting film forms than said ladder via hole shines and the said upward big window technique of the laser of the diameter same light beam diameter in hole.