KR20070037323A - Method for manufacturing printed wiring board, and printed wiring board using the same - Google Patents

Abstract

The manufacturing method of the wiring board of this invention forms an ultra-thin conductive metal layer on the surface of a support base material, forms a resist pattern on the surface of this ultra-thin conductive metal layer, and on the surface of the ultra-thin conductive metal layer which is not covered by this resist pattern, After forming the plating layer of thickness substantially the same as this resist pattern by electroplating, a nodule is formed in the electroplating on the surface of this formed plating layer, and then the adhesive bond layer of the base film which has an adhesive bond layer on the surface of an insulating film After contacting, injecting the nodule into the adhesive layer, peeling off the supporting substrate, transferring the resist pattern and plating layer formed on the supporting substrate to the base film side, and then removing the resist pattern transferred to the base film side, It forms a copper conductor pattern on the surface of a base film, It is characterized by the above-mentioned. According to this invention, a conductor pattern can be formed in the convex shape of the insulating film surface, and this conductor pattern has high peeling strength.

Description

Manufacturing method of wiring board and wiring board {METHOD FOR MANUFACTURING PRINTED WIRING BOARD, AND PRINTED WIRING BOARD USING THE SAME}

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows typically the cross section in each process of the wiring board manufacturing method of this invention.

It is sectional drawing which shows typically the cross section in each process in the other aspect of the manufacturing method of the wiring board of this invention.

It is sectional drawing which shows typically the cross section in each process in the other aspect of the manufacturing method of the wiring board of this invention.

[Description of Symbols for Main Parts of Drawing]

10: support substrate

12: ultra-thin conductive metal layer

14: cured product of photosensitive resin

16: concave

18: conductor pattern

20: nodule

22: adhesive layer

24: insulation film

30: base film

32: adhesive layer

[Patent Document 1] Japanese Patent Application Laid-Open No. 2000-71387

[Patent Document 2] Japanese Patent Application Laid-Open No. 9-64514

[Patent Document 3] Japanese Patent Application Laid-Open No. 11-251722

[Patent Document 4] Japanese Patent Application Laid-Open No. 4-260389

[Patent Document 5] Japanese Patent Application Laid-Open No. 11-266069

[Patent Document 6] Japanese Patent Application Laid-Open No. 11-266070

This invention relates to the manufacturing method of the wiring board by the transfer method, and the wiring board formed by this manufacturing method.

Generally, a wiring board forms the photosensitive resin coating film on the surface of the metal layer laminated | stacked on the base material surface, exposes and develops this photosensitive resin coating film, and forms the masking material which left the photosensitive resin hardened | cured body in the desired shape, and this It forms by the method (subtractive method) of etching the metal layer of the part in which the masking material is not formed. In such a conventional method, it is common that a so-called cross-sectional wiring pattern having a short upper cross-sectional length of the formed wiring pattern and a long insulating film side (lower) cross-sectional length are formed (undercut phenomenon). Moreover, in the conventional method as described above, there is a limit to the width of the wiring pattern to be formed, and the method of forming a wiring pattern thinner than the recent fine pitch wiring pattern is approaching a limit.

As a completely different method by the above subtractive method, the transfer method of adhering the conductor pattern formed as a separate body from the insulating film on the insulating film is known.

However, in this transfer method, for example, as disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2000-71387) or Patent Document 2 (Japanese Patent Laid-Open No. Hei 9-64514), the conductor pattern may be an insulating substrate or the like. There is a problem in that the wiring board which is buried in the base material of the substrate and manufactured by the transfer method as described above cannot adopt anisotropic conductive adhesion, for example, and a method established in the conventional wiring board cannot be employed.

Further, as disclosed in Patent Document 3 (Japanese Patent Application Laid-open No. Hei 11-251722) or Patent Document 4 (Japanese Patent Application Laid-open No. Hei 4-260389), a conductor pattern can be formed in a convex shape on the surface of an insulating substrate. Even if it can, the peeling strength of the conductor pattern with respect to an insulated substrate does not become high enough by the method described in such patent document 3 or patent document 4. In addition, Patent Document 5 (Japanese Patent Laid-Open No. 11-266069) and Patent Document 6 (Japanese Patent Laid-Open No. 11-266070) disclose inventions of a transfer method focusing on peel strength, but are described in these publications. In this method, it is very difficult to form a fine pitch conductor pattern.

An object of the present invention is to provide a wiring board by a novel transfer method and a method of manufacturing the same.

In more detail, an object of this invention is to provide the wiring board which can form the conductor pattern of very fine pitch, and has the high peeling strength of the conductor pattern transferred with respect to the insulated substrate, and its manufacturing method.

Moreover, this invention can form the conductor pattern of very fine pitch, and is a wiring board with high peeling strength of the conductor pattern transferred with respect to the insulated substrate, Comprising: The conductor pattern is formed in convex shape on the surface of an insulated substrate, It is an object to provide a wiring board which can be attached to an electronic device by anisotropic conductive adhesion and its manufacturing method similarly to the conventional wiring board.

The manufacturing method of the wiring board of this invention forms an ultra-thin conductive metal layer on the surface of a support base material, forms a resist pattern on the surface of this ultra-thin conductive metal layer, and applies it to the surface of the ultra-thin conductive metal layer which is not covered by this resist pattern. After forming a plating layer having a thickness substantially the same as that of the resist pattern by electroplating, a nodule was formed by electroplating on the surface of the formed plating layer, and then the adhesive layer of the base film having the adhesive layer on the surface of the insulating film. After contacting and injecting the said nodule into this adhesive bond layer, the support base material was peeled off, the resist pattern and plating layer formed on the support base material were transferred to the base film side, and the resist pattern transferred to the base film side was then removed. It forms a copper conductor pattern on the surface of a base film, It is characterized by the above-mentioned.

As mentioned above, in the manufacturing method of the wiring board of this invention, a nodule is formed in the surface of a conductor pattern, this nodule penetrates into the adhesive bond layer of a base film, and the contact surface with an adhesive becomes large, and the projection of this nodule ), The conductor pattern has a high peel strength with respect to the base film.

Next, the manufacturing method of the wiring board of this invention and the wiring board obtained in this way are demonstrated concretely.

1 is a cross-sectional view showing an example of a cross section of a substrate in each step in the method of manufacturing a wiring board of the present invention.

As shown to Fig.1 (a), (b), in the manufacturing method of the wiring board of this invention, the ultra-thin conductive metal layer 12 is formed in the surface of the support base material 10. As shown to FIG.

Here, as the support base material 10, the film, sheet | seat, board | plate, etc. which were formed from insulating resin, such as a synthetic resin film and a synthetic resin plate, can be used normally. Although there is no restriction | limiting in particular in the thickness and shape of such a support base material 10, When manufacturing a wiring board continuously in this invention, it has a synthetic resin film which has magnetic form supportability and has flexibility, or A sheet is preferable, and when using a synthetic resin sheet or a synthetic resin film as such support base material 10, the thickness of this support base material 10 is 15-50 micrometers normally, Preferably it is 35-70 micrometers. It is in range. Moreover, since the ultra-thin conductive metal layer 12 is formed on the surface of this support base material 10 by sputtering etc., it is preferable to have some heat resistance, and poly is an example of resin which forms such a support base material 10. Mid, polyimide amide, polyamide; Polyester, such as PET and PEN, is mentioned. In particular, in the present invention, it is preferable to use a film or sheet formed from PET or polyimide.

The ultrathin conductive metal layer 12 is formed on the surface of the supporting substrate 10 as described above. In the present invention, the ultra-thin conductive metal layer 12 is an electrode for depositing the conductor metal when the conductor pattern 16 is formed by electroplating, and is formed from conductive metals such as copper, nickel, and chromium. Such an ultra-thin conductive metal layer 12 can be formed by depositing the conductive metal as described above on the surface of the supporting substrate 10 using a deposition method such as sputtering, vapor deposition, plating, or the like. The ultra-thin conductive metal layer 12 may be one capable of supplying sufficient electric power to plate the conductor metal in a later step, and the thickness thereof is not particularly limited, but is usually 5 × 10 ⁻³ to 5 μm, preferably 5 ×. ^10-3 is to 3㎛ degree. Especially in this invention, it is preferable to form this ultra-thin conductive metal layer 12 by sputtering. When forming the ultra-thin conductive metal layer 12 by sputtering in this way, it is 5 thickness using copper or nickel as a conductive metal. × 10 ^-3 to 5㎛, preferably, it is preferable that the conductive metal layer of 5 × 10 ^-3 to O.1㎛.

After forming the ultra-thin conductive metal layer 12 in this manner, the photosensitive resin layer is formed on the surface of the ultra-thin conductive metal layer 12, and the recessed part 16 is formed by exposing and developing this photosensitive resin layer. Although there exist photosensitive resin of the type hardened | cured by exposure and photosensitive resin of the type which becomes soluble by exposure, photosensitive resin can use all types of photosensitive resin in this photosensitive resin. It is preferable that the coating thickness of such photosensitive resin is made substantially the same as the thickness of the conductor pattern to be formed, and the thickness of the photosensitive resin layer formed in this way is 5-30 micrometers normally, Preferably it is 8-20 micrometers It is in range. The cross section of the state which exposed and developed the above photosensitive resin layer is shown in FIG.1 (c). In FIG.1 (c), the photosensitive resin layer is exposed and developed, and the recessed part 16 is formed in the bottom part of this recessed part 16, and the recessed part 16 is formed in the bottom part of this recessed part 16. FIG. (12) is exposed.

In this manner, the photosensitive resin is exposed and developed to form the recessed portion 16, and then metal is deposited on the recessed portion 16 to form a conductor pattern. FIG. 1D shows a cross section of a state in which a conductive metal is precipitated by electroplating to form a conductor pattern 18 in the recess 16 formed by exposing and developing the photosensitive resin layer as described above. have. Although the conductor pattern 18 can be formed with various electroconductive metals, such as copper, nickel, aluminum, silver, gold, for example, in this invention, it is preferable to form with copper or a copper alloy. Although the thickness of the conductor pattern 18 at this time can be made substantially the same as the thickness of the hardened body 16 of the photosensitive resin, the conductor pattern 18 is formed by forming the nodule 20 on the surface of the conductor pattern 18 in a later process. It is preferable to form a little thinner than the hardened | cured material 16 of photosensitive resin because the thickness of a) becomes a little thick.

Such conductor pattern 18 is formed by electroplating. That is, using the ultrathin conductive metal layer 12 as one electrode, the conductive metal is deposited on the surface of the ultrathin conductive metal layer 12 by electroplating. The electroplating conditions at this time are, for example, when the conductor pattern 18 is formed of copper, the plating current density of 0.5 to 8 A / dm 2, the copper ion concentration of 10 to 100 g / liter in the plating solution, and the plating temperature of 20 to 20 It is preferable to set it as 60 degreeC and plating time 6 to 80 minutes. By electroplating on such conditions, a dense copper plating layer can be formed. In addition, the plating liquid used for formation of the conductor pattern used here is the plating liquid generally used. In addition, in this invention, the metal which forms this conductor pattern 18 and the metal which forms the ultra-thin conductive metal layer 12 may be same or different.

After the conductor pattern 18 is formed as described above, the nodule 20 is formed on the surface of the conductor pattern 18 as shown in Fig. 1E. The nodule 20 is usually a dendritic metal plating having a height of 0.1 to 15 µm, and can be formed by electroplating in the same manner as in the production of the conductor pattern 18 described above. The nodule 20 is for firmly fixing the conductor pattern 18. The nodule 20 is not particularly required to be the same as the metal forming the conductor pattern 18. However, the nodule 20 and the conductor pattern 18 may not be required. In order to form integrally, it is preferable to form with the same metal. For example, when the conductor pattern is formed of copper or a copper alloy, it is preferable that the nodule 20 also be formed of copper or a copper alloy.

Plating conditions in the case of forming this nodule 20 from copper or a copper alloy include a plating current density of 3 to 30 A / dm 2, a copper ion concentration of 1 to 50 g / liter in a plating solution, a plating temperature of 20 to 60 ° C., and a plating time of 5 To 600 hours, preferably 5 to 480 seconds.

As a copper plating bath used when the nodule 20 is formed of copper or a copper alloy, a copper sulfate bath, copper chloride copper plating bath and the like are very suitable.

By electroplating as mentioned above, copper precipitates in resin form and the nodule 20 is formed. The height of this nodule 20 is to fix the conductor pattern 18 in the adhesive layer 22, and is usually in the range of 0.1 to 15 mu m, preferably 1 to 10 mu m. The nodule 20 thus formed penetrates into the adhesive layer of the base film to be bonded in the next step and firmly fixes the conductor pattern to the adhesive layer.

After forming the nodule 20 in this manner, protrusion forming plating and coating plating may be performed on the nodule formed as needed. Protrusion forming plating is a plating method of depositing a fine particle metal in the formed nodule 20, and coating plating is a plating method of coating and fixing the fine particle metal deposited in this way by projection plating.

After forming the nodule 20 as described above, the nodule formed by bonding the insulating film 24 and the base film 30 having the adhesive layer 22 to the inside of the adhesive layer 22 as described above ( Invade 20).

In FIG. 1F, the cross section in which the insulating film 24 and the base film 30 having the adhesive layer 22 formed on the surface of the insulating film 24 are bonded to the surface on which the nodule 20 is formed is shown. Is shown. The base film 30 adhere | attached here has the insulating film 24 and the adhesive bond layer 22, As an example of the resin material which forms the insulating film 24, polyimide, polyimide amide, polyester, polyphenyl Lene sulfide, polyether imide, fluororesin, liquid crystal polymer, epoxy resin, glass-epoxy resin composite, and the like. There is no restriction | limiting in particular in the thickness of this insulating film 24, A plate-like or flexible film form may be sufficient.

When this base film 30 is plate-shaped, a plate-shaped board | substrate can be formed using an epoxy resin, a glass-epoxy resin composite, etc., for example.

In addition, when the base film 30 is a film shape which has flexibility, it can form and use a film from the above resin. Although the thickness of the film at this time changes with resin used, it is usually 70 micrometers or less, Preferably it exists in the range of 5-70 micrometers. Especially in this invention, it is preferable to use a polyimide film, and the polyimide film used at this time is 5-70 micrometers normally, Preferably it is 3-70 micrometers, Especially preferably, the thickness in the range of 30-45 micrometers Have

This insulating film 24 may be a single layer or a laminate in which a plurality of layers are laminated. In addition, when this insulating film 24 is a laminated body in which several layers were laminated | stacked, several layers are laminated | stacked by the adhesive agent component, and the outermost layer (the outermost layer in which the conductor pattern is not formed) laminated as needed. It can also peel and use it. In this case, in order to make peeling easy, the insulation which has a several layer structure like the insulation film main body / mold release layer / adhesive / reinforcement film is interposed through the layer which consists of a mold release agent on the surface of the insulation film laminated by an adhesive agent. The film 24 can be used.

When the reinforcing film is peeled off in this manner, the adhesive is peeled off together with the reinforcing film, but in most cases, the release layer made of a silicon compound or a silicon resin is transferred to the back surface of the insulating film main body and remains on the insulating film main body side. many. Thus, by leaving a mold release layer, the base film formation component can be prevented from fusion | melting on the surface of a bonding tool.

The adhesive bond layer 22 which forms the base film 30 used by this invention penetrates the nodule 20 formed in the previous process, and fixes the conductor pattern 18, for this reason, The thickness of the adhesive layer 22 formed is determined by referring to the height of the nodule 20. As described above, since the height of the nodule 20 is usually in the range of 0.1 to 15 μm, preferably 1 to 10 μm, the thickness of the adhesive layer 22 is equal to the height of this nodule or Or more, it is preferable, and it has a thickness of 1-24 micrometers normally, Preferably it is 2-15 micrometers.

In this invention, it is preferable that the adhesive layer which comprises this base film 30 uses a thermosetting adhesive agent. As such a thermosetting adhesive agent, an epoxy resin adhesive, a polyimide adhesive, an acrylic adhesive, a urethane adhesive, etc. are mentioned. In particular, in the present invention, it is preferable to use an epoxy adhesive and / or a polyimide adhesive. That is, the epoxy adhesive and the polyimide adhesive soften to the extent that the nodule 20 penetrates by heating in the precursor state before curing, but the adhesive is cured by further heating after the nodule 20 penetrates and is firm. The cured body of the adhesive is formed. The cured product of such an adhesive not only exhibits good acid resistance, but also softens even when heated in a later step, and firmly holds the conductor pattern 18 by the anchor effect of the nodule 20.

In order to adhere the base film 30 as described above to the supporting substrate on which the nodule 20 is formed, the base film 30 is placed so that the surface on which the adhesive layer 22 of the base film 30 and the nodule 20 are formed faces each other. It arrange | positions and usually pressurizes under heating, and lamination | stacking. By heating in this way, the adhesive bond layer 22 softens, and the nodule 20 easily penetrates into the adhesive bond layer 22, and by further pressurizing, the nodule infiltrates the softened adhesive bond layer 22. Moreover, at least one part of the adhesive agent which forms the adhesive bond layer 22 in the state which the nodule 20 penetrated is hardened by heating.

In addition, the temperature required for softening of the adhesive bond layer 22 is 100-200 degreeC normally, and the pressure required to intrude the nodule 20 into this adhesive bond layer 22 is linear pressure. In the range of 0.5 to 4.Okg / cm. On the other hand, in order to cure the adhesive bond layer 22 more reliably, after sticking a base film as mentioned above, it can also be preserve | saved in the heating furnace adjusted to the temperature within 100-300 degreeC range.

The laminated body laminated | stacked as mentioned above is a support base material 10 / ultra-thin conductive metal layer 12 / photosensitive resin hardened | cured material 14, conductor pattern 18 (nodule 20, as shown to FIG. 1 (f)). ), The adhesive layer 22, and the base film 24 has a laminated constitution.

In the manufacturing method of the wiring board of this invention, the support base material 10 is peeled from the laminated body formed as mentioned above. A cross-sectional view in which the support base material 10 is peeled off is shown in FIG. 1G, and the ultrathin conductive metal layer 12 is exposed on one surface by peeling off the support base material 10.

In this invention, in order to remove this ultra-thin conductive metal layer 12, the laminated body shown by FIG.1 (g) is etched and the ultra-thin conductive metal layer 12 is dissolved and removed.

Since the ultra-thin conductive metal layer 12 is made of copper, a copper alloy, nickel, etc., and the ultra-thin conductive metal layer 12 is very thin, it can be easily removed using the etching liquid generally used. In FIG. 1H, the ultra-thin conductive metal layer 12 is removed to expose the surface of the conductor pattern 18. By removing the ultra-thin conductive metal layer 12 in this manner, the conductor patterns 18 are in an electrically independent state.

In addition, in this invention, it is preferable that the layer which consists of mold release agent resins, such as a silicon compound, is arrange | positioned at the surface in which the conductor pattern 18 of the base film 30 is not formed. If such a layer is present when mounting the electronic component, fusion of the bonding tool base film forming component can be prevented.

After removing the ultra-thin conductive metal layer 12 in this manner, the cured body 14 of the photosensitive resin between the conductor patterns 18 is removed to make the conductor pattern 18 independent. Although the hardened | cured material 14 of the photosensitive resin can be removed by various methods, the method of eluting using a solvent or the method of peeling and removing using an alkaline washing liquid are advantageous. As an organic solvent used here, the organic solvent which does not invade the insulating film 24 and the adhesive bond layer 22 which comprise the base film 30 can be used. In addition, since the hardened | cured material 14 of the photosensitive resin is normally peeled easily using an alkaline washing liquid, the removal method using an alkaline washing liquid is the most realistic and very advantageous at low cost.

The cross section of the wiring board in the state which removed the hardened | cured material 14 of the photosensitive resin and independent of a conductor pattern as shown above is shown to FIG. 1 (i).

In the method of this invention, when peeling the support base material 10 from FIG.1 (f), you may peel the ultra-thin conductive metal layer 12 with the support base material 10. FIG. The ultra-thin conductive metal layer 12 is formed on the surface of the support base material 10 by sputtering or the like, but the sputtering conditions and the like do not increase the adhesion of the ultra-thin conductive metal layer 12 to the support base material 10 at this time. The adhesiveness of the ultra-thin conductive metal layer 12 with respect to the support base material 10 can be improved by changing the or the conditions for forming the ultra-thin conductive metal layer 12. Thus, when the ultra-thin conductive metal layer 12 is firmly bonded to the surface of the support base material 10, when the support base material 10 is peeled off, the ultra-thin conductive metal layer 12 also peels together with this support base material 10, FIG. It will be in the state shown by (h ') of FIG. 2, not through (g) state of (b). Thus, when all the ultra-thin conductive metal layers 12 are peeled at the time of peeling of the support base material 10, even if the etching process for removing the ultra-thin conductive metal layer 12 is abbreviate | omitted, the wiring shown to (i ') of FIG. Substrates can be prepared.

In addition, instead of adhering the base film 30 which consists of the adhesive bond layer 22 and the insulating film 24 in FIG.1 (f), as shown to FIG.3 (f "), an adhesive bond layer By thickening (32) and hardening this adhesive bond layer 32, it can be set as an insulating film as shown to (i ") of FIG. In this form, the hardened | cured material of the adhesive bond layer 32 is used as an adhesive bond layer, and it is also used as an insulation film, and it can be set as the wiring board which has a layer structure much smaller than the wiring board mentioned above. As resin which forms such an adhesive bond layer 32, the precursor of a polyimide, etc. can be used, for example.

In the wiring board of this invention formed as mentioned above, as shown to FIG. 1 (i), FIG. 2 (i '), and FIG. 3 (i "), the conductor pattern 18 is a base film 30 ) Or the conductor pattern formed from the surface of the hardened | cured material of the adhesive bond layer 32 which acts equivalently to the base film 30 at substantially right angle, does not undercut.

Therefore, according to the method of the present invention, since the sphericity of the conductor pattern to be formed is high, and it is not necessary to consider the narrowing of the space 26 between the conductor patterns due to the undercut, an extra space is provided between the conductor patterns. There is no need to secure it. Furthermore, in the present invention, a photosensitive resin is exposed to form a space for forming a conductor pattern, and a conductive metal is deposited in this space to form a conductor pattern. The exposure accuracy of the photosensitive resin is very high, and the conductor pattern is formed of the photosensitive resin. Since it forms by depositing a metal in the space formed by hardened | cured material, exposure of the photosensitive resin can be formed to the wavelength of the light used for exposure finely, and this point and the photosensitive resin make the space substantially perpendicular to a support base material. Since it can be formed, it becomes possible to form the very fine conductor pattern whose line | wire width which was not able to manufacture by the conventional method is much less than 1 micrometer.

Furthermore, since the conductor pattern 18 thus formed is firmly fixed to the adhesive layer by the anchor effect of the nodule 20, the conductor pattern 18 has a very high peel strength.

Moreover, in the wiring board obtained by the method of this invention, the conductor pattern is formed in convex shape on the base film surface, and it can be attached to the electronic device using an anisotropic conductive adhesive like a conventional printed wiring board.

EXAMPLE

Next, although an Example is described about the manufacturing method of the wiring board of this invention, and the wiring board manufactured by this method, this invention is demonstrated in detail, but this invention should not be limited by these.

[First Embodiment]

A polyimide film having a thickness of 38 µm was used as the supporting substrate, and an ultrathin layer having an average thickness of 0.1 µm was formed on one surface of the polyimide film that is the supporting substrate by sputtering.

Subsequently, the photosensitive resin layer (average dry thickness: 13 micrometers) was formed in the surface of this ultra-thin copper layer, and the predetermined pattern was formed by exposing and developing this photosensitive resin layer. The ultra-thin layer was exposed at the bottom of the portion where the photosensitive resin layer of the pattern thus formed was removed.

Subsequently, it puts into the commercially available copper sulfate plating bath (copper concentration: 24 g / liter) of the laminated body in which the pattern was formed as mentioned above, and electroplated by the conditions of plating current density 2.0A / dm <2>, plating temperature 300 degreeC, and plating time 20 minutes. Was carried out to deposit copper with a thickness of 8 占 퐉 on average in a portion where the photosensitive resin was not formed to form a conductor pattern. On the other hand, the thickness of the copper which precipitated was formed thinner by 5 micrometers than 13 micrometers in thickness of the photosensitive resin layer.

Next, the obtained laminate was placed in a copper sulfate plating bath (copper concentration: 8 g / liter) and subjected to electrocopper plating under conditions of a plating current density of 1 A / dm 2, a plating temperature of 30 ° C., and a plating time of 480 seconds, and averaged on the surface of the conductor pattern. The nodule of 3 micrometers in height was formed.

Subsequently, the base film was adhere | attached on the surface in which this nodule is formed. This base film has a 38-micrometer-thick polyimide film and an 8-micrometer-thick epoxy adhesive layer formed in one side of this polyimide film, and the epoxy-based adhesive softens by heating and is formed in the surface of the said conductor pattern. The nodules are softened to such an extent that they penetrate into the epoxy-based adhesive layer. On the other hand, an extremely thin silicon resin layer is formed on the surface opposite to the surface on which the adhesive layer is formed.

The base film was arrange | positioned so that the surface in which this epoxy pressure-sensitive adhesive layer and the nodule were formed may be faced and crimped under the conditions of a temperature of 150 ° C. × line pressure 2.Okgf / cm, and the mixture was maintained at 160 ° C. for 5 hours under pressure.

After hardening an adhesive bond layer as mentioned above, the support base material was peeled off, and the ultra-thin layer was exposed to this peeling surface.

This laminated body was etched by the ultra-thin layer using the copper etching liquid, and the conductor pattern was exposed.

Subsequently, it wash | cleaned using alkali washing liquid, the hardened | cured material of the photosensitive resin was peeled off, and the conductor pattern was independent.

The peel strength of the conductor pattern formed as mentioned above was measured, and this peel strength was 1.4 kgf / cm. The peel strength of the conductor pattern in the wiring board obtained by the present invention was remarkably high, in contrast to the fact that the peeling strength of the conductor pattern of the wiring board formed in the same manner except that no nodule was formed was 0.33 kgf / cm. have. Moreover, the peeling strength of the wiring pattern in the printed wiring board obtained by arrange | positioning copper foil on the polyimide film surface and selectively etching this copper foil is about 1.0-2.5 kgf / cm normally, According to the method of this invention, The wiring board which has a conductor pattern of the peeling strength equivalent to or more than can be manufactured.

Moreover, as mentioned above, the conductor pattern formed by the method of this invention protrudes in convex shape from the surface of an insulating film, and is formed. Therefore, as a result of anisotropic conductive bonding using the wiring pattern obtained as described above, good electrical conduction was ensured in the pressing direction, and the insulation in the width direction was also good.

Second Embodiment

In Example 1, it operated similarly except changing adhesiveness of a sputtering metal and a support base material by changing the sputtering conditions with respect to a support base material.

After the nodule was formed, the supporting substrate was peeled off after the base film was bonded. As a result, the ultrathin copper foil layer was peeled off together with the supporting substrate. Therefore, since the ultra-thin layer was also peeled by exfoliating the support base material and the conductor pattern was exposed on the peeling surface, the implementation of the etching step for removing the ultra-thin layer was omitted.

Subsequently, it wash | cleaned using alkali washing liquid, the hardened | cured material of the photosensitive resin was peeled off, and the conductor pattern was independent.

The peel strength of the conductor pattern formed as mentioned above was measured, and this peel strength was 1.4 kgf / cm. The peel strength of the conductor pattern in the wiring board obtained by the present invention was remarkably high, in contrast to the fact that the peeling strength of the conductor pattern of the wiring board formed in the same manner except that no nodule was formed was 0.33 kgf / cm. have. Moreover, the peeling strength of the wiring pattern in the printed wiring board obtained by arrange | positioning copper foil on the polyimide film surface and selectively etching this copper foil is about 1.0-2.5 kgf / cm normally, According to the method of this invention, The wiring board which has a conductor pattern of the equivalent or more peeling strength can be manufactured.

Moreover, as mentioned above, the conductor pattern formed by the method of this invention protrudes in convex shape from the surface of an insulating film, and is formed. Therefore, as a result of anisotropic conductive bonding using the wiring pattern obtained as described above, good electrical conduction was ensured in the pressing direction, and the insulation in the width direction was also good.

[Industry availability]

According to the present invention, a very fine pitch conductor pattern can be formed by the transfer method. Moreover, although this conductor pattern is formed by the transfer method, it has high peel strength with respect to a base film.

Moreover, since a conductor pattern is formed in convex shape from the base film surface, it can be attached to an electronic device by anisotropic conductive adhesion similarly to the conventional film carrier tape.

In the method of the present invention, since the photosensitive resin is exposed and developed in a desired shape, the concave portion formed is plated to form a conductor pattern, and after the nodule is formed on the surface of the conductor pattern, the conductor pattern is transferred to the base film. The side surface of the cross section of the conductor pattern is formed almost perpendicular to the surface of the insulating film, so that the cross-sectional shape of the conductor pattern of the wiring board produced by the method of the present invention is formed into a rectangle. Thus, since the cross-sectional shape of a conductor pattern is rectangular, undercut phenomenon etc. like the wiring pattern manufactured by the conventional method do not appear, a very fine conductor pattern can be densely formed.

Moreover, since the wiring pattern obtained by the method of this invention protrudes in convex shape and is formed in the insulating film surface, it mounts to an electronic device using an anisotropic conductive adhesive similarly to the printed wiring board manufactured by the conventional method. can do.

According to the present invention, a very fine pitch conductor pattern can be formed by the transfer method. Moreover, this conductor pattern has a high peeling strength with respect to a base film, although it is formed by the transfer method.

In the method of the present invention, since the photosensitive resin is exposed and developed in a desired shape, the concave portion formed is plated to form a conductor pattern, and after the nodule is formed on the surface of the conductor pattern, the conductor pattern is transferred to the base film. , The side surface of the conductor pattern cross section is formed almost at right angles to the surface of the insulating film, so that the cross-sectional shape of the conductor pattern of the wiring board produced by the method of the present invention is formed into a rectangle. Thus, since the cross-sectional shape of a conductor pattern is rectangular and undercut phenomenon like the wiring pattern manufactured by the conventional method does not appear, a very fine conductor pattern can be formed densely.

Claims (9)

An ultrathin conductive metal layer is formed on the surface of the supporting substrate, a resist pattern is formed on the surface of the ultrathin conductive metal layer, and a plating layer having a thickness substantially the same as that of the resist pattern is applied to the surface of the ultrathin conductive metal layer not covered by the resist pattern. After forming by plating, a nodule is formed on the surface of the formed plating layer by electroplating, and then the adhesive layer of the base film having an adhesive layer is brought into contact with the surface of the insulating film and the nodule is infiltrated into the adhesive layer. After that, the support substrate was peeled off, and the resist pattern and the plating layer formed on the support substrate were transferred to the base film side. Then, the resist pattern transferred to the base film side was removed, and a copper conductor pattern was placed on the surface of the base film. It forms, The manufacturing method of the wiring board characterized by the above-mentioned. The method of claim 1, The ultra-thin conductive metal layer is a conductive layer having a thickness of 5 × 10 ⁻³ to 5 μm formed on the surface of the supporting substrate by sputtering or precipitation reaction of the conductive metal. The method of claim 1, The said resist pattern is formed by forming a photosensitive resin layer on the surface of an ultra-thin conductive metal layer, and exposing and developing this photosensitive resin layer, The manufacturing method of the wiring board characterized by the above-mentioned. The method of claim 1, The nodule is a copper nodule, and the electroplating conditions for forming this nodule are current density of 3 to 30 A / dm 2, plating liquid temperature of 20 to 60 ° C., copper ion concentration of 1 to 50 g / liter in plating liquid, and plating time of 5 to 600 It is for a second, The manufacturing method of the wiring board characterized by the above-mentioned. The method of claim 1, The said base film is a polyimide film of average thickness 15-150 micrometers, The adhesive layer of average thickness 1-24 micrometers which consists of an epoxy-type thermosetting resin is formed in the surface of this base film. The method of claim 1, After transferring the resist pattern and the plating layer formed on the support substrate to the substrate film side and removing the support, the wiring substrate characterized in that the ultra-thin conductive metal layer remaining on the surface of the transferred resist pattern and the plating layer is removed by etching. Method of preparation. The nodule integrated with this conductor pattern is formed in the base film side bottom part of a wiring pattern, This nodule penetrates into the resin cured body which comprises a base film, and this conductor pattern is fixed to the base film, The wiring board characterized by the above-mentioned. . The method of claim 7, wherein The side surface in the cross section of the said conductor pattern is formed in substantially perpendicular to the surface of a base film, The wiring board characterized by the above-mentioned. The method of claim 7, wherein The said base film consists of a polyamide film of average thickness 5-70 micrometers, and the thermosetting adhesive of average thickness 1-24 micrometers laminated | stacked on this polyimide film.

Images