CN102308679B

CN102308679B - Method of manufacturing multi-layered printed circuit board

Info

Publication number: CN102308679B
Application number: CN201180000967.4A
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: 2013-05-01
Anticipated expiration: 2031-01-25
Also published as: CN102308679A; JP5485299B2; TW201146123A; WO2011096293A1; JPWO2011096293A1; 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 manufacture method of multilayer printed-wiring board

Technical field

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

Background technology

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

Therefore, at printed wiring board mounting electronic parts 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).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, on the two sides of this core substrate or single face be formed with accumulation horizon (build up layer) about 1 ~ 2 layer.Increase in the stratotype multilayer flexible printed wiring plate at this, in order to be electrically connected the core substrate of accumulation horizon and internal layer, be provided with that inwall to via hole (leading universal hole) that die bed is arranged applies electroplating processes and the plating via hole that obtains interlayer conduction.

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

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 also become large with the thickness of its conductor layer that forms at accumulation horizon accordingly.Outer field circuit pattern is to form by 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 as outer field circuit pattern, be difficult on accumulation horizon to high-density mounting electronic parts.

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

, in increasing the multilayer flexible printed wiring plate of stratotype, from the viewpoint of the raising of densification and design freedom, what special requirement 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 consists of, the overlapping interlayer connecting portion that is consisted of by the plating via hole of accumulation horizon and the structure that disposes.

Can cheap and stably make the multilayer printed-wiring board with lamination pore structure that can high-density installation is expected 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 by laser processing is disclosed.According to disclosed method in these documents, can form expeditiously the ladder via structure., in the method, the cathode copper that is used for covering to electroplate epithelium the inwall of ladder via hole is electroplated normally once to concentrate and is carried out.The tendency that therefore, the plating epithelium attenuation that the sidewall in the lower 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 to explain the manufacture method that increases stratotype multilayer printed-wiring board prior art, that have the lamination pore structure.Fig. 3 is the process profile that has the manufacture method that increases the stratotype multilayer printed-wiring board of lamination pore structure for explanation.

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

Then, as from Fig. 3 (1) as can be known, to this two sides copper clad laminate 104, forming by 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, by to Copper Foil 102,103 and have end via hole 105 to apply conductive treatment and metallide afterwards to process, 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 the interlayer conduction section that die bed is arranged that is electrically connected as Copper Foil 102 and Copper Foil 103 to pliability insulating substrate 101, be electroplate with end via hole 106.

Then, as from Fig. 3 (1) as can be known, by photo-fabrication (photofabrication) Copper Foil 102 and Copper Foil 103 pattern according to the rules of pliability insulating substrate 101 carried out etching, form circuit pattern (internal layer circuit pattern).In more detail, a series of operation by being made 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, from Fig. 3 (1) as can be known, for example 12 μ m are thick for the dielectric film 107(for preparing at polyimide film etc.) have a cover layer 109 of adhesive layer 108.Adhesive layer 108 consists of such as the binding agent by acrylic acid, epoxy etc.Then, use vacuum laminator etc., carry out in the lamination operation 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 fill the inwall that is electroplate with end via hole 106 with binding agent fully.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 at the single face of pliability insulating substrate (for example thick polyimides of 25 μ m) the single face copper clad laminate 111 of Copper Foil (for example thickness 12 μ m).By 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 with peristome become the deposited shape mask (being also referred to as metal mask) that the laser shading is used.The opening that forms at Copper Foil is used for removing by laser processing the resin of the pliability insulating substrate that exposes in the bottom surface of this opening etc., forms via hole.

Then, from Fig. 3 (2) as can be known, use the binding agent that is used for increasing layer at two sides core substrate 110, will have the single face copper clad laminate 111,111 of deposited shape mask (conformal mask) via adhesive layer 112,112 stacked surface and the back side that is bonded to two sides core substrate 110 respectively.

Then, from Fig. 3 (2) as can be known, carry out laser processing by the deposited shape mask that uses single face copper clad laminate 111, form ladder via hole 113A and via

hole

113B, 113C.

Then, from Fig. 3 (3) as can be known, by 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 conductive treatment and metallide is afterwards processed, 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 layer via hole 114A, a 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, from Fig. 3 (3) as can be known, by using photo-fabrication single face copper clad laminate 111,111 Copper Foil pattern are according to the rules carried out etching, form external circuit pattern 115,115.Afterwards, corresponding to needs, form photosensitive solder resist agent (Photo solder resist) layer (not shown), 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 by 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.From Fig. 3 (3) as can be known, 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 plating and increase layer via hole 114A and form a lamination pore structure.In increasing stratotype multilayer printed-wiring board 116, be connected interlayer and connect and to be undertaken by being electroplate with end via hole 106 in the surface of two sides core substrate 110 with the back side.

Have again, from Fig. 3 (3) as can be known, increase stratotype multilayer printed-wiring board 116 and have: be laminated with the parts installation portion 116a of accumulation horizon and the 116b of flexible cable section that extends from this parts installation portion 116b at two sides core substrate 110.The 116b of this flexible cable section 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 to fill fully., be electroplate with end via hole 106, apply electroplating processes with inwall at the via hole that connects two sides copper clad laminate 104 and the perforation via hole that forms is compared, be difficult to filling adhesive.This is because electroplating the perforation via hole can fill from 2 directions at 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 to electroplate the perforation via hole is connected, and is difficult to avoid thickening.Thus, increasing layer via hole 113 deepens.So, as described above, become large for the electroplating thickness of guaranteeing the reliability that interlayer connects.For example, when the formation plating increases layer via hole 114A, a 114B, 114C, need to be used to form the metallide of the plating epithelium about 25 ~ 30 μ m as mentioned above.Suppose that Copper Foil (12 μ m are thick) at single face copper clad laminate 111 carries out in 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 is undertaken by wet etching, to form the circuit spacing be fine circuit pattern about 100 μ m so be difficult to high finished product rate ground.

As mentioned above, 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 manufacture method that increases the stratotype multilayer printed-wiring board with lamination pore structure of energy high-density installation.

Be used for solving the scheme of problem

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

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

By described the 1st conducting film and described the 2nd conducting film pattern are according to the rules carried out etching, thereby make the 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 described dielectric film,

Under the following conditions, namely filling described plating fully by the binding agent after the described tectal described adhesive layer melting connects the inside of via hole and allows under the condition that produces the space of not filled by described binding agent the described inside that is electroplate with end via hole, carry out described tectal lamination operation is pasted on the two sides of described two sides flexible base plate, make thus the two sides core substrate

In the described at least opening surface side that is electroplate with end via hole of described two sides core substrate, stacked bonding has the accumulation horizon of the 3rd conducting film that forms at single face,

By laser processing, remove the described described binding agent that is electroplate with via hole inside, the end, described space is disappeared, thus, expose the described end via hole that is electroplate with in the bottom, form the described ladder via hole that end via hole becomes lower hole that is electroplate with,

Apply electroplating processes by the inwall to described the 3rd conducting film and described ladder via hole, form the plating that described the 3rd conducting film and described internal layer circuit pattern are electrically connected and increase a layer via hole,

Carry out etching by described the 3rd conducting film pattern according to the rules that will implement electroplating processes, form the outer circuit pattern.

The effect of invention

According to above-mentioned feature, 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 electroplate with end via hole by what the surface of two sides flexible base plate and the back side were electrically connected, and is electroplate with plating that end via hole disposes at this and increases layer via hole and consist of.This plating increases layer via hole outer circuit pattern and internal layer circuit pattern is electrically connected, and is that the inwall of ladder via hole that has end via hole to make the hole of minor diameter that will form at the two sides flexible base plate is formed with the hole of electroplating epithelium.Thus, formation increases the ladder via structure that layer via hole consists of by the plating that is electroplate with end via hole and form thereon.

By such feature, according to an embodiment of the invention, when cover layer is carried out lamination, do not need the complete filling adhesive in the inside that is electroplate with end via hole that forms at the two sides flexible base plate.Its reason is that when forming described 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 as much as possible the thickness of adhesive layer.

As a result, compared with prior art, the ladder via hole is shoaled.Thus, to increase layer via hole and carry out metallide when processing in order to form to electroplate, the electro-deposition easiness improves, and the thermal expansion of structural elements increases impact from layer via hole to plating is alleviated.

Therefore, according to the present invention, rate of finished products is improved, can reduce in order to ensure the needed electroplating thickness of connection reliability of via hole wiring.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 electroplating when increasing layer via hole, also form the metallide epithelium on the end via hole being electroplate with of two sides flexible base plate.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 mentioned above 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 patterns that forms at the two sides flexible base plate.

As mentioned above, 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 for the process profile that the manufacture method that increases the stratotype multilayer printed-wiring board that embodiments of the present invention relate to is described.

Figure 1B is for following Figure 1A, the process profile of the manufacture method that increases the stratotype multilayer printed-wiring board that embodiments of the present invention relate to being described.

Fig. 1 C is for following Figure 1B, the process profile of the manufacture method that increases the stratotype multilayer printed-wiring board that embodiments of the present invention relate to being described.

Fig. 2 is the profile that increases the stratotype multilayer printed-wiring board that embodiments of the present invention relate to.

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

Embodiment

Below, on one side with reference to accompanying drawing, the manufacture method that increases the stratotype multilayer printed-wiring board with lamination pore structure that relates to for embodiments of the present invention on one side describes.

Have again, give prosign to the structural element with same function, omit detailed explanation.In addition, accompanying drawing is schematically, represents centered by the characteristic that execution mode relates to, and 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 manufacture method that increases stratotype multilayer printed-wiring board 32 with lamination pore structure that relates to for embodiments of the present invention describes.

Figure 1A to Fig. 1 C is that this increases the process profile of the manufacture method of stratotype multilayer printed-wiring board 32 for explanation.Fig. 2 is the profile that increases stratotype multilayer printed-wiring board 32 that present embodiment relates to.

At first, from Figure 1A (1) as can be known, prepare the thick polyimides of 25 μ m for example at pliability insulating substrate 1() the two sides have respectively Copper Foil 2 and Copper Foil 3(the 1st conducting film and the 2nd conducting film) double-sided copper-clad laminated sheet 4.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 from Figure 1A (1) as can be known, 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 in 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

Copper Foil

2,3 peristome of the diameter identical with the path aperture is set, forms deposited shape mask.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 the 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 the present embodiment, 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 Ear Mucosa Treated by He Ne Laser Irradiation is the roughening processing of low roughness.Thus, using carbon dioxide laser (wavelength: about 9.8 μ m) when carrying out laser processing, the absorption of

Copper Foil

2,3 laser is stably improved.In the present embodiment, the MULTIBOND150 of the Japanese Macdermid of use Co., Ltd. in this roughening is processed.Thus, can guarantee to electroplate with the cathode copper that in the operation of back, forms the adhesion of epithelium 7, and the absorption of the carbon dioxide laser in the surface of Copper Foil is improved.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 the present embodiment, simultaneously processing connects via hole 5 and end via hole 6 is arranged again.Therefore, process by the surface of Copper Foil 2 being carried out above-mentioned roughening, can make the handling ease of Copper Foil 2.And, preferably be formed with the end during via hole 6 not connecting the mode of Copper Foil 3, process as the back side of Copper Foil 3 that to make copper-clad surface be the processing of low roughness, the absorption of laser is reduced.But, form expeditiously in the situation that connects via hole 5 in hope, preferably process as the back side of Copper Foil 3 and carry out the roughening processing.

The Copper Foil 2 of two sides copper clad

laminate

4,3 thinner, easier

generation Copper Foil

2,3 perforation when laser processing.Therefore, under the thickness of wishing Copper Foil as present embodiment is thinner situation below the 10 μ m, for the formation that makes end via hole 6 is easy, processes as the back side and to implement hardly roughening and process, preferably use the Copper Foil 3 of low roughness.

Here, the mode for laser processing at length describes.At first, describe for the situation that is processed with end via hole 6.When processing Copper Foil 2, improve the each time energy (being made as power P) of the laser of emission.And, preferably finish 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 the energy of the laser of launching each time be reduced to (1/2) P ~ (1/3) P, finishes the processing of resin with 2 ~ 3 emissions.Then, narrate for the situation that connects via hole 5.In this case, the energy of the laser that use will be launched each time is made as the laser of above-mentioned power P, and Copper Foil and the resin on two sides are processed.Carry out continuously 3 ~ 4 emissions and shine, finish the processing that connects via hole 5.

And then using in 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 roughening processes.Then, the surface from Copper Foil 3 processes formation perforation via hole 5.According to the method, the formation of end via hole 6 is become easily, and can form expeditiously the perforation via hole.In addition, as other method, carry out laser processing from 2 directions on the surface of the surface of Copper Foil 2 and Copper Foil 3, form and connect via hole 5 and also can.In this case, process because roughening is carried out on

Copper Foil

2,3 surface, so have following advantage, i.e. processing from any direction is all easy, and does not need to consider the state (height of roughness) that process at the back side of Copper Foil.

Then, in order to remove form to connect via hole 5 and dirty (gum residue) that the end produces during via hole 6 arranged, carry out plasma treatment and wet etching (dirty Transformatin).For connecting via hole 5 and having optimal conditions end via hole 6, that this plasma is processed roughly the same.On the other hand, for 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, by etching,

Copper Foil

2,3 retreats, and exists the conductive treatment to the back to cause dysgenic situation.On the other hand, for end via hole 6 is arranged, process the metal not of the same race of the nickel, chromium etc. at the back side of the Copper Foil 3 that causes in order to remove the back side, need the etching of 1 ~ 2 μ m.Consideration is preferably finished processing with few etch quantity of trying one's best to the impact that connects via hole 5.In the present embodiment, carry out the etching of 1 μ m.

Then, from Figure 1A (2) as can be known, by on the

Copper Foil

2,3, connect the inwall of via hole 5 and have the inwall of end via hole 6 to apply conductive treatment and cathode copper electroplating processes afterwards, to electroplate the about 8 μ m of epithelium 7(thick thereby form cathode copper).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 conductive paths that this plating connects via hole 9, and being electroplate with end via hole 10 is interlayer conductive paths 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 conductive treatment operation 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, basically carrying out operation under with the condition that can process end via hole 6 flows.For the cathode copper electroplating work procedure, near the easy variation of uniformly-coating of the sidewall the bottom that end via hole 6 is arranged.Thus, the cathode copper electroplating processes is preferably carried out with the electroplating bath of the copper sulphate that contains high concentration.

Then, from Figure 1A (3) as can be known, form resist

layer

11,11 at copper electrodeposited coating 8,8.In the formation of this resist layer 11, use dry film photoresist.This dry film photoresist preferably uses the dry film photoresist that can cover the thickness (for example 20 μ m) of (tenting) to electroplating the both sides that connect via hole 9 and be electroplate with end via hole 10.Thus, can prevent that resist from entering plating and connecting via hole 9 and be electroplate with in the end via hole 10, make the peeling off of resist layer 11 of carrying out later become easy.Have again, replace dry film photoresist, also can use aqueous resist or electro-deposition resist.

Then, from Figure 1A (4) as can be known, utilize photo-fabrication, exposure, development by 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 respectively internal

layer circuit pattern

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

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

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

layer circuit pattern

12A, 12B and plating perforation via hole 9 is filled by adhesive layer 15.

In this lamination operation, need to not fill the inside that is electroplate with end via hole 10 fully with binding agent.Namely, the lamination operation is carried out under the following conditions, that is, fill the inside that electroplate to connect via hole 9 fully by the binding agent after adhesive layer 15 meltings of cover layer 16, and allow and produce the space 15a that the binding agent after not bonded dose layer 15 melting in inside that are electroplate with end via hole 10 is filled.Like this, connect via hole 9 as long as the thickness of the adhesive layer in the present embodiment 15 can fill to electroplate fully, do not need to consider to be electroplate with the occupied state of end via hole 10 inside.Thus, adhesive layer 15 is thin as much as possible in can filling the scope of electroplating perforation via hole 9 fully.In the present embodiment, 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 by 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 the thick polyimides of 25 μ m for example at pliability insulating substrate 19() single face have Copper Foil 18(the 3rd conducting film that for example 12 μ m are thick) single face copper clad laminate 20.And, by photo-fabrication, at the Copper Foil 18 formation peristome 18a of single face copper clad laminate 20.More specifically, form resist layer (not shown) at Copper Foil 18, by exposure and development this resist layer is carried out composition.Then, with composition resist layer as mask, Copper Foil 18 is carried out etching.Thus, form deposited shape mask 21.The resin that this peristome 18a is used for removing base material in the operation of back by laser processing forms via hole.

Then, from Figure 1B (6) as can be known, use the binding agent that is used for increasing layer, will be formed with the single face copper clad

laminate

20,20 of deposited shape mask 21 via adhesive layer 22, the 22 stacked two sides that are bonded to two sides core substrate 17.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, from Fig. 1 C(7) as can be known, use deposited shape mask 21 to carry out laser processing, form ladder via hole 23 and via hole 24A, 24B.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, the resin that is electroplate with end via hole 10 inside is removed entirely, and 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, in order to form ladder via hole 23, also need to remove the resin that is electroplate with end via hole 10 inside.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, from Fig. 1 C(8) as can be known, by on the Copper Foil 18, the inwall of the inwall of ladder via hole 23 and via

hole

24A, 24B applies conductive treatment and metallide is afterwards processed, 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 electroplate via hole all to internal

layer circuit pattern

12A, 12B and Copper Foil 18 and copper electrodeposited coating 26(outer circuit pattern 30 described later) be 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 the present embodiment, 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.

From Fig. 1 C(8) as can be known, by operation so far, finish being electroplate with end via hole 10 and be formed with and electroplate the lamination pore structure increase layer via hole 27.

Then, as can be seen from Figure 2, by using photo-fabrication Copper Foil 18 and metallide epithelium 25 pattern are according to the rules carried out etching, form outer circuit pattern 30.Afterwards, corresponding to needs, form photosensitive solder resist agent layer (not shown), 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 by utilizing metal pattern etc. carries out sharp processing.

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

Increasing in the stratotype multilayer printed-wiring board 32 that present embodiment relates to, at surface and the back side of the two sides core substrate 17 that becomes internal layer, be laminated with outer field single face copper clad

laminate

20,20 via adhesive layer 22,22.Present embodiment is not limited to this, only on the surface of two sides 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 stacked outer field single face copper clad laminates 20.Thus, can obtain only to possess at single face the multilayer printed-wiring board of accumulation horizon.

Internal

layer circuit pattern

12A, 12B increase layer via

hole

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

Have, the stratotype multilayer printed-wiring board 32 that increases that the manufacture method that relates to by present embodiment obtains has again: the parts mounting layer 32a that is laminated with accumulation horizon 31 at the two sides core substrate 17 as the pliability printed wiring board; And the 32b of flexible cable section that does not have stacked accumulation horizon at two sides core substrate 17.That is, the 32b of flexible cable section is the structure of extending from parts installation portion 32a.Present embodiment is not limited to this, and the multilayer printed-wiring board that manufacturing two sides core substrate 17 does not consist of flexible cable 32b also can.

In addition, in the present embodiment, be illustrated for the manufacture method 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 after Copper Foil 18 formation are than the large opening of the diameter in the upper hole of ladder via hole 23 the large window technique of the laser of the beam diameter that irradiation is identical with the diameter in the upper hole of ladder via hole 23 etc.The laser processing method that can select is not limited to the method used in the explanation of above-mentioned execution mode, can at random select to apply shape method, Direct Laser method and large window technique according to each operation.Have, in the situation of using the Direct Laser method, as present embodiment, the thickness of preferred Copper Foil is below the 15 μ m again.

In addition, in the present embodiment, 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, at two sides core substrate 17 stacked accumulation horizons, but the present invention is not limited thereto, the single face copper clad laminate that replaces cover layer 16 to use with binding agent directly arranges accumulation horizon to two sides flexible base plate 13 and also can.In this case, make as follows multilayer printed-wiring board.At first, as described above, make to be formed with and electroplate the two sides flexible base plate 13 that connects via hole 9, is electroplate with end via hole 10 and internal layer circuit pattern 12A, 12B.Afterwards, prepare to cover the conductive film layer pressing plate with the single face of adhesive layer the adhesive layer that it has insulating substrate, the conducting film (the 3rd conducting film) that forms on the surface of described insulating substrate, forms at the back side of described insulating substrate.Then, carry out pasting the lamination operation of covering the conductive film layer pressing plate with the single face of adhesive layer on the two sides of two sides flexible base plate 13.This lamination operation is carried out under the following conditions, namely, cover binding agent after the adhesive layer melting of conductive film layer pressing plate by the single face with adhesive layer and fill electroplate the inside that connects via hole 9 fully, and allow and produce the space that the binding agent after the not bonded dose of layer melting in inside that is electroplate with end via hole 10 is filled.To the multilayer printed-wiring board of such acquisition, remove the binding agent that is electroplate with end via hole 10 inside by laser processing, the space is disappeared, thus, expose in the bottom and to be electroplate with end via hole 10, form and be electroplate with the ladder via hole that end via hole 10 becomes lower hole.Afterwards, apply electroplating processes by the inwall to the 3rd conducting film and ladder via hole, form the plating that the 3rd conducting film and internal layer circuit pattern 12A are electrically connected and increase a layer via hole.Then, carry out etching by the 3rd conducting film pattern according to the rules that will implement electroplating processes, form the outer circuit pattern, obtain to increase the multilayer printed-wiring board of stratotype.

As mentioned above, two sides core substrate 17 have 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 consists of by being electroplate with end via hole 10 and increasing layer via hole 27 in this plating that is electroplate with 10 configurations of end via hole.It is that the end via hole 10 that is electroplate with that forms at two sides core substrate 17 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 and connect the interlayer conduction that surface and the back side of two sides core substrate 17 are only carried out in via hole 10 employings, do not carry out the structure of the interlayer conduction of outer circuit pattern 30 and internal

layer circuit pattern

12A, 12B.

By above-mentioned feature, obtain following effect according to present embodiment.

When cover layer 16 is carried out lamination, no longer need to fill the inside that is electroplate with end via hole 10 fully with binding agent.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, fully in the scope of filling adhesive, can reduce as much as possible the thickness of the adhesive layer 15 of cover layer 16 to the inside that electroplate to connect via hole 9.As a result, can make as much as possible ladder via hole 23 more shallow (for example about 10 μ m), the electro-deposition easiness when applying metallide and process to the inwall of ladder via hole 23 and via hole 24A, 24B improves.And then, electroplate and to increase layer via hole 27,28, the 29th, be difficult to be subject to the favourable structure of impact etc. of thermal expansion of the structure member of printed wiring board.The coefficient of thermal expansion of binding agent that particularly consists of adhesive layer 15 in structural elements is large, and therefore by making adhesive layer 15 attenuation, effect is large.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 present embodiment, can form fine outer circuit pattern 30.

And then, according to present embodiment, 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 present embodiment, be reinforced because be electroplate with end via hole 10, 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.As a result, the needed time of electroplating work procedure is shortened, and can reduce cost.In addition, because coordination galvanization has the electroplating thickness of 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, in the explanation of execution mode, wiring pattern and electroplate epithelium and be made of copper, but the present invention is not limited thereto is such as being that other metals such as aluminium, silver also can again.

Based on above-mentioned record, so long as those skilled in the art may 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 concept of the present invention that interior perhaps its coordinate that does not break away from the scope defined that is required by the technical program is derived and purport, can carry out variously appending, changing and the deletion of part.

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 section.

Claims

1. the manufacture method 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 described dielectric film,

2. the manufacture method of a multilayer printed-wiring board is characterized in that,

Preparation is covered the conductive film layer pressing plate with the single face of adhesive layer, the adhesive layer that it has insulating substrate, the 3rd conducting film that forms on the surface of described insulating substrate and forms at the back side of described insulating substrate,

Under the following conditions, namely filling described plating fully by the binding agent after the described adhesive layer melting connects the inside of via hole and allows under the condition that produces the space of not filled by described binding agent the described inside that is electroplate with end via hole, carry out the lamination operation that described single face with adhesive layer covers the conductive film layer pressing plate is pasted on the two sides of described two sides flexible base plate

3. the manufacture method of multilayer printed-wiring board according to claim 1 and 2, it is characterized in that, described laser processing is carried out by the following method, namely, the deposited shape laser processing method that the deposited shape mask that forms with described the 3rd conducting film is carried out etching carries out, Direct Laser processing method to described the 3rd conducting film direct irradiation laser, perhaps at the diameter large opening of described the 3rd conducting film formation than the upper hole of described ladder via hole, the large window technique of the laser of the diameter same light beam diameter in irradiation and described upper hole.