KR20080020077A - Printed circuit board with high density and manufacturing method thereof - Google Patents

Abstract

A printed circuit board with high density and a manufacturing method thereof are provided to have high adhesive force of a copper plated layer, reliability between circuits of a build-up resin composition layer and an insulating layer, and an excellent heat resistant property and an excellent chemical-resistant property after the absorption of moisture. A method of manufacturing a printed circuit board with high density includes the step1 of providing a double-sided copper clad layer formed by stacking copper foils so that a concave-convex portion(104) of a copper mat surface having a surface roughness of 0.2 to 7 micrometers is buried on both surfaces of a resin substrate(101); the step2 of forming a buried copper foil layer by etching a copper foil in a thickness direction excluding the buried concave-convex portion; the step3 of forming an electroless copper plated layer(105) on a substrate on which the buried copper foil layer is formed; the step4 of forming a electrolytic pattern copper plated layer(107) on the electroless copper plated layer; and the step5 of removing the electroless copper plated layer and the buried copper foil layer in a region without the electrolytic pattern copper plated layer.

Description

Printed circuit board with high density and manufacturing method

1A to 1H are cross-sectional views schematically illustrating a manufacturing process flow of a printed circuit board according to an exemplary embodiment of the present invention.

2A to 2G are cross-sectional views schematically illustrating a manufacturing process flow of a printed circuit board according to another exemplary embodiment of the present invention.

3A to 3H are cross-sectional views schematically illustrating a manufacturing process flow of a printed circuit board according to Comparative Example 1 of the present invention.

4A to 4H are cross-sectional views schematically illustrating a manufacturing process flow of a printed circuit board according to Comparative Example 4 of the present invention.

※ Explanation of code about main part of drawing ※

101, 201, 301, 401: resin substrate

102, 202, 302, 402: copper foil

103, 203, 303, 403: Via Hole

104, 204, 304, 404: uneven portion

105, 305, 405: Electroless Copper Plating Layer

106, 206, 306, 406: plating resist

107, 207, 307, 407: Electrolytic pattern copper plating layer

The present invention relates to a high density printed circuit board and a method of manufacturing the same. More specifically, the present invention forms a pattern circuit through the electroless / electrolytic copper plating after forming the buried copper foil layer so as to embed the uneven portion of the copper foil mat surface having a surface roughness (Rz) of 0.2 ~ 7㎛ on the resin substrate The present invention relates to a high-density printed circuit board and a method for manufacturing the same, which have good adhesion between copper and a substrate resin and can realize high-density fine circuits.

In recent years, in electronic devices that have become smaller, thinner, and lighter, the circuit width and the distance between circuits of printed circuit boards have become even narrower, and have become 25/25 μm or less from the conventional line / space = 50/50 μm. In such a microcircuit, in order to form a fine pattern of line / space = 25/25 탆 or less using a double-sided copper-clad laminate as a core, the copper foils on both sides of the copper-laminated laminate are etched and removed, followed by electroless copper plating and electrolytic copper plating. However, a method of forming a fine circuit (see Japanese Patent Application Laid-Open No. 10-13016) has been proposed, but the copper foil having a large surface roughness has a disadvantage in that a mass yield is lowered when forming a fine circuit according to this method.

In general, a copper foil laminated sheet having a thickness of 3 to 5 µm is used. However, in the case where a fine circuit having a line / space = 25/25 µm or less is formed by using such a copper laminated sheet, copper thickness is obtained after copper plating after hole processing. 20 μm or more, when the subsequent subtractive method is applied, mass production yield is lowered, and mass production is difficult.

Moreover, semi-additive resin compositions are generally used as the resin composition for build-up (see Japanese Patent Laid-Open Nos. 06-260756 and 06-275959), and semi-annealed by using a UV-selective thermosetting build-up resin composition. Although the method of manufacturing by the additive method (refer to the photo via method and Japanese Unexamined-Japanese-Patent No. 07-304931) is applied, the resin composition for semiadditives uses many resins and additives which are easy to match in order to improve the adhesive force of copper plating. In addition, since the UV selective thermosetting type contains many UV-curable resins and various additives, there are problems in heat resistance after moisture absorption, chemical resistance, long-term reliability, and the like. . In addition, the addition amount of the inorganic filler for improving the stiffness is also limited according to the restriction, the physical properties reinforcement is required for bending, skewing and the like. Furthermore, since the epoxy resin is used, there is a limit to the characteristics of the high frequency furnace and there is a limit to use for high frequency applications.

Accordingly, in the present invention, extensive research has been conducted to solve the problems described above. As a result, a copper foil mat surface having a surface roughness (Rz) of 0.2 to 7 µm is formed on the base of the electroless / electrolytic copper plating layer of the pattern circuit. By further forming a buried copper foil layer formed by embedding the uneven portion, a printed circuit board having a high-density fine circuit could be manufactured with high reliability, and the present invention was completed based on this.

Accordingly, an aspect of the present invention is to provide a high-density printed circuit board having a good adhesive force between a copper foil and a resin substrate, and having excellent heat resistance and chemical resistance characteristics after moisture absorption and a manufacturing method thereof.

Another aspect of the present invention is to provide a high-density printed circuit board and a method for manufacturing the same, which are excellent in long-term reliability such as migration resistance, have small warpage and skew, and are applicable to high frequency applications.

The printed circuit board according to the preferred embodiment of the present invention is:

Resin substrates; And

A pattern circuit layer formed on both sides of the resin substrate;

Including;

A buried copper foil layer in which the pattern circuit layer is formed by embedding uneven portions of a copper foil mat surface having a surface roughness Rz of 0.2 to 7 µm on a resin substrate, an electroless copper plating layer formed on the buried copper foil layer, and the It characterized in that it comprises an electrolytic copper plating layer formed on the electroless copper plating layer.

According to another preferred embodiment of the present invention, a printed circuit board includes:

Resin substrates; And

A pattern circuit layer formed on the resin substrate;

Including;

The pattern circuit layer includes a buried copper foil layer formed by embedding uneven portions of a copper foil mat surface having a surface roughness Rz of 0.2-7 μm on a resin substrate, and an electrolytic copper plating layer formed on the buried copper foil layer. do.

Preferably, the uneven part of the said copper foil mat surface has surface roughness Rz of 0.3-5 micrometers.

Method of manufacturing a printed circuit board according to an embodiment of the present invention:

(a) providing a double-sided copper foil laminated plate formed by laminating copper foils so that uneven parts of a copper foil mat surface having a surface roughness Rz of 0.2 to 7 μm are embedded on both sides of a resin substrate;

(b) forming a buried copper foil layer by etching copper foil in a thickness direction except for the buried uneven parts;

(c) forming an electroless copper plating layer on the substrate on which the buried copper foil layer is formed;

(d) forming an electrolytic pattern copper plating layer on the electroless copper plating layer; And

(e) removing the electroless copper plating layer and the buried copper foil layer of the portion where the electrolytic pattern copper plating layer is not formed;

Characterized in that it comprises a.

According to another preferred embodiment of the present invention, a method of manufacturing a printed circuit board includes:

(a) providing a double-sided copper foil laminated plate formed by laminating copper foils so that uneven parts of a copper foil mat surface having a surface roughness Rz of 0.2 to 7 μm are embedded on both sides of a resin substrate;

(b) forming a buried copper foil layer by etching copper foil in a thickness direction except for the buried uneven parts;

(c) forming an electrolytic pattern copper plating layer on the substrate on which the buried copper foil layer is formed; And

(d) removing the buried copper foil layer at the portion where the electrolytic pattern copper plating layer is not formed;

Characterized in that it comprises a.

The method may further include forming a via hole for interlayer electrical conduction in the resin substrate before (b) or after (b).

Preferably, the thickness of the copper foil etched in the step (b) is 5 μm or less.

Hereinafter, a preferred embodiment of the present invention will be described in more detail with reference to the accompanying drawings.

As described above, in the present invention, the adhesive strength of the copper foil is good, the heat resistance after moisture absorption and the chemical resistance characteristics are excellent, and the long-term reliability such as migration resistance is excellent, the warpage and the warpage are small, and the high density which can be used also for high frequency applications A printed circuit board is provided.

The substrate according to the present invention can be applied to a compact high density multilayer printed circuit board for connecting semiconductor chips by wire bonding or flip chip bonding, and can be applied to both inner layers and / or build up layers. In addition, the printed circuit board according to the present invention can be applied to a high-density semiconductor plastic package for multi-terminal use, such a semiconductor plastic package can be used as an electronic device by bonding to the motherboard printed circuit board using a solder ball or the like.

According to the present invention, since a fine circuit can be implemented in any layer such as an inner layer or a buildup layer, a high density printed circuit board can be manufactured.

1A to 1H schematically illustrate a manufacturing process flow of a printed circuit board according to an exemplary embodiment of the present invention, which will be described with reference to the following.

First, a double-sided copper-clad laminate in which copper foils 102 and 202 are laminated on both sides of a resin substrate 101 for use as an inner layer plate and / or an outer layer plate is prepared (see FIG. 1A).

The resin composition for the resin substrate 101 usable in the present invention is not particularly limited and may include both thermosetting resins and / or thermoplastic resins known in the art.

As said thermosetting resin, well-known thermosetting resin compositions, such as an epoxy resin, a cyanate ester resin, a maleimide resin, a polyimide resin, a polyfunctional addition polyphenylene ether resin, and a benzocyclobutene resin, can be used individually or in combination of 2 or more types. Can be.

In particular, when it is necessary to lower the dielectric properties of the resin substrate for use in high frequency applications, it is preferable to use a cyanate ester resin composition, a functional group-added polyphenylene ether resin composition, or the like as the thermosetting resin. Moreover, in order to avoid the transmission loss etc. at the high frequency of 20 GHz or more, it is preferable to use a liquid-crystal polyester fiber material as a cyanate ester resin composition alone or a base material, without using glass fiber.

Although it does not specifically limit as said cyanate ester resin, Preferably it is 1, 3- or 1, 4- dicyanate benzene, 1, 3, 5- tricyanate benzene, 1, 3-, 1, 4-, 1,6-, 1,8-, 2,6- or 2,7-dicyanatenaphthalene, 1,3,6-tricyanatenaphthalene, 4,4-dicyanatebiphenyl, bis (4-cyanate Phenyl) methane, 2,2-bis (4-cyanatephenyl) propane, 2,2-bis (3,5-dibromo-4-cyanatephenyl) propane, bis (4-cyanatephenyl) ether, Bis (4-cyanatephenyl) thioether, bis (4-cyanatephenyl) sulfone, tris (4-cyanatephenyl) phosphite, tris (4-cyanatephenyl) phosphate, and novolaks with cyanide halides Cyanates obtained by reaction can be mentioned, Among these, 1 type (s) or 2 or more types can be used in combination.

In addition, Japan's 41-11712, 43-1468, 44-447, 44-4791, 46-41112, 47-26853, 51-51, and 51- Cyanate esters disclosed in 63149 can also be used. Moreover, the prepolymer of the molecular weight 400-6,000 which has a triazine ring formed by trimerization of the cyanate group of such a cyanate ester compound can be used. The prepolymer can be obtained by reacting according to a known method. For example, acids, such as mineral acid and a Lewis acid, are mentioned for the said cyanate ester monomer; Bases such as tertiary amines such as sodium alcoholate; It can obtain by superposing | polymerizing on salts, such as sodium carbonate, as a catalyst. Since the prepolymer includes unreacted monomers to form a mixture of the monomer and the prepolymer, they can be suitably used as the thermosetting resin component of the present invention. Furthermore, liquid cyanate esters can be used, and one or two or more thereof can be used in combination. Of course, bromine adducts and phosphorus inclusions in these molecules can also be used. However, in the case of nonhalogen, bromine adducts are not used.

When using the said thermosetting resin composition in a liquid phase, it can use a liquid thermosetting resin in combination, and can add a various additive as needed, and it can be set as a suitable liquid resin composition.

Various well-known additives can be mix | blended in the high heat resistant reversible resin among the said thermosetting resins. For example, various kinds of thermosetting resins, thermoplastic resins, known organic inorganic fillers, dyes, pigments, thickeners, lubricants, antifoaming agents, dispersants, leveling agents, photosensitizers, gloss agents, polymerization initiators, thixotropic agents and the like other than those described above. Additives may be added in combination according to the purpose and use. In addition, an appropriate amount of a curing agent and a catalyst may be added to the compound having a reactor, if necessary. In addition, a flame retardant, flame retardant with bromine, non-halogen type, non-flame retardant, etc. which added the well-known flame retardant of non-halogen generally can be used. Flame retardants may be used in combination of one or two or more of the unreacted, reactive and the like.

The thermosetting resin composition itself is cured by heating, but since the curing rate is slow and workability and economy may be relatively low, a known hardening agent and a catalyst may be used if necessary. The usage-amount generally uses 0.005-10 weight part with respect to 100 weight part of thermosetting resins, Preferably 0.01-5 weight part is used.

Meanwhile, as the thermoplastic resin composition, a liquid crystal polyester resin composition having a melting point of 270 ° C. or more capable of withstanding reflow treatment may be used, and a mixture of two or more kinds may be used. Of course, a mixture of a thermosetting resin and a thermoplastic resin can also be used. The molecular structure can use a well-known thing. Although the melting point of the thermoplastic resin is not particularly limited, it is preferable to use a 270 占 폚 or more that is very suitable to withstand the processing when the printed circuit board. Although thickness is not specifically limited, Preferably it is 3-200 micrometers, More preferably, it is good to set it as 5-150 micrometers. If the thickness is thin, if the through-hole is in the inner layer board, the through-hole cannot be sufficiently filled with the resin composition. Therefore, an appropriate thickness is selected in consideration of this, and the thickness is appropriately so that the conductor circuit of the printed circuit board can be embedded. Choose.

It is possible to put a reinforcing base material in the above-mentioned resin composition. For example, a glass woven base material, a glass nonwoven base material, an organic woven base material, an organic nonwoven base material, such a mixed grass base material, etc. can be used. As the glass fiber, a woven or nonwoven substrate using a known fiber such as E, T (S), NE, D, or quartz may be used. Although it does not specifically limit as organic fiber, For example, liquid crystalline polyester fiber, wholly aromatic fiber, polyoxybenzazole fiber, etc. can be used individually or in mixture. Furthermore, the mixed grass of an inorganic fiber and an organic fiber, the mixed grass of each yarn, etc. can be used.

Moreover, a heat resistant film base material can also be used. For example, copper foil laminated plates, such as a polyimide film, a wholly aromatic polyamide film, and a liquid crystalline polyester film, etc. can be used.

On the other hand, as the copper foil 102 laminated on both sides of the resin substrate 101, the uneven portion 104 of the mat surface, that is, the surface roughness Rz is 0.2 to 7 µm, preferably 0.3 to 5 µm, and more. Preferably, the thing of 0.4-3.5 micrometers is used. Although the copper foil thickness except the uneven part 104 of a mat surface is not specifically limited, Generally 1-18 micrometers is used. As such copper foil, an electrolytic copper foil, a rolled copper foil, a copper alloy etc. can be used, Most preferably, an electrolytic copper foil is good.

According to the present invention, a double-sided copper-clad laminate having the above-described copper foil 102 attached to both sides is used as an inner layer plate and / or an outer layer plate (see FIG. 1A). In addition, even when building up, it is also possible to multiply using the semi-additive resin composition, but since the long-term reliability may be relatively poor, it is preferable to improve the strength, such as chemical resistance, and long-term reliability. More preferably, using a B-stage thermosetting resin composition sheet excellent in the back, a B-stage thermosetting resin composition sheet (prepreg) of substrate reinforcement has a surface roughness (Rz) of 0.2 to 7 μm on the outside thereof. It is good to laminate | stack and multilayer by using copper foil in which a mat surface is embedded.

On the other hand, the inner-side double-sided copper-clad laminate or the multilayered double-sided copper-clad laminate for lamination as described above, the copper foil 102 in the thickness direction so that only copper of the uneven portion 104 of the copper foil mat surface embedded in the resin substrate 101 remains substantially. ) To form a buried copper foil layer by etching and removing the buried copper foil layer to form a through hole and / or a blind via hole 103 for interlayer electrical conduction; Alternatively, the buried copper foil layer may be formed by first forming the through hole and / or the blind via hole 103 and then etching away the copper foil 102 in the thickness direction except for the uneven portion 104 embedded in the resin substrate 101. . 1B and 1C show the latter case, and show an example in which a hole diameter of about 100 μm is processed. In this case, when the hole is processed, a part of the copper foil remains to be partially protruded (see FIG. 1B). On the other hand, after the hole processing / copper foil etching, it is preferable to perform a desmear treatment in order to improve adhesion in the subsequent process.

The hole processing method is not particularly limited, and a general method known in the art may be used. For example, through hole processing uses a metal drill or an NC drill device, and the rotational speed is typically processed at 8 to 300,000 rpm. The hole diameter can be suitably adjusted according to an application purpose, and is generally 70 micrometers-1.0 mm. On the other hand, when the hole is processed using a laser, the hole diameter is generally 80 to 150 μm for a carbon dioxide gas laser, and the hole diameter is generally 20 to 20 for a UV-YAG laser or a UV-vanadate laser. 100 μm. On the other hand, in the case of using a carbon dioxide laser, the blind hole processing generally processes a hole diameter of 60 to 150 µm, and in this case, desmear treatment after the hole processing is performed because resin residues are present on the copper foil at the bottom of the blind via hole. desirable. In the case of using a UV-YAG laser or a UV-vanadate laser, the hole diameter is generally 20 to 100 µm. Of course, it is also possible to use the above-mentioned apparatuses together, and it is preferable to use a well-known auxiliary material suitable for hole processing at the time of hole processing.

The etching liquid used at the time of forming the buried copper foil layer is not particularly limited, and any etching liquid known in the art can be used. As the etching method, for example, the liquid can be uniformly sprayed on the copper-clad laminate, and the copper foil of the entire plate can be uniformly dissolved. The etching method is not limited thereto, and any method known in the art can be applied.

The matt surface uneven portion 104 of the buried copper foil layer formed after such an etching process is preferable in view of improving adhesion with the electroless / electrolytic copper plating layer formed thereon in a subsequent process which will be described later as much as possible. It is preferable in that not only the circuit peeling defect by the resin flow at the time of circuit formation and lamination but also the peeling defect by contact etc. in the process can be reduced.

On the other hand, the thickness of the copper foil 102 removed in the etching process is preferably 5㎛ or less in that it can minimize the etching thickness variation appearing at the edge and the center of the substrate when etching a large area of the substrate.

Next, after the electroless copper plating layer 105 is formed on the substrate 101 on which the buried copper foil layer 104 is formed (see FIG. 1D), a pattern plating resist such as a dry film ( 106 is applied (see FIG. 1E) and the electrolytic pattern copper plating layer 107 is formed using a conventional electrolytic plating method (see FIG. 1F), and then the pattern plating resist 106 is removed (see FIG. 1G). In this case, after applying the pattern plating resist first before electroless plating, electroless copper plating and electrolytic copper plating may be sequentially performed.

Although the thickness of the electroless copper plating layer 105 formed from this is not specifically limited, It is typical that it is 0.3-1.5 micrometers, Preferably it is 0.7-1.0 micrometer. In addition, the thickness of the electrolytic copper plating layer 107 is not particularly limited, but is typically 10 to 25 µm in consideration of productivity, electrical characteristics, and the like.

In addition, although copper plating is performed inside the hole through the copper plating process described above, hole portions such as blind via holes and the like may be simultaneously filled with copper plating. The method of filling the inside of a hole with copper plating is not specifically limited, A well-known plating method can be used. In the case where the through-hole is not filled with copper plating, the inside of the hole may be filled before the laminate molding with a supplemental resin. However, from the viewpoint of workability and productivity, it is preferable to simultaneously laminate-form and to fill the inside of the through-holes plated with the resin composition for lamination (resin composition for build-up).

Subsequently, flash etching is performed as known in the art to remove the electroless copper plating layer 105 and the buried copper foil layer 104 of the portion where the electrolytic pattern plating layer 107 is not formed to obtain a fine circuit (FIG. 1H). Reference).

On the other hand, it is also possible to use a substrate with a circuit layer formed as described above as an inner layer substrate, and further build up here to manufacture a multilayer substrate. In this case, the surface of the pattern circuit of the inner layer substrate is subjected to chemical treatment, for example, black copper oxide treatment, Mack's CZ treatment, or the like, as necessary, and then a multilayer resin composition (build-up resin composition) on both surfaces thereof. The copper foil was applied to the outside, and the laminate was formed under heating, pressurization, and vacuum according to a known method, and then a fine circuit was formed through a machining process as described above to manufacture a multilayer printed circuit board. In this case, the degree of curing of the resin to be built up is not particularly limited, and may be carried out in a semi-cured state (for example, 50 to 90% curing), and may be post-cured after copper plating and / or circuit formation. Finally, it is typically carried out with a degree of curing which does not cause problems in properties.

On the other hand, the lamination molding conditions are not particularly limited, but generally 5 to 120 minutes at a temperature of 100 to 300 ℃, preferably 110 to 250 ℃, a pressure of 1 to 50 kgf / cm 2 and a vacuum degree of 10 mmHg or less Molding is common. Usually, the laminate molding is performed under vacuum, and the degree of vacuum is preferably performed at 30 mmHg or less.

For example, when laminating and bonding a liquid-crystal polyester resin composition layer, Preferably, a liquid-crystal polyester resin composition sheet is arrange | positioned on both surfaces of an inner layer board, a copper foil is placed on the outer side, and a liquid-crystal polyester resin melt | dissolves At a temperature of 1 to 50 kgf / cm 2, preferably 5 to 30 kgf / cm 2, at a temperature of at least 10 to 50 ° C. above the melting point, preferably 1 to 60 minutes under vacuum, preferably 2 to 40 The laminate is molded for one minute and integrated to give a double-sided copper clad laminate.

Subsequently, a noble metal plating resist, which is a soldering resist, may be formed on the surface of the substrate as known in the art, and nickel plating and gold plating may be performed. In order to make the whole non-halogen, for example, UL94V-0, the self-extinguishing thing is used for the resin composition used and the noble metal plating resist which is a soldering resist. In this case, if the resist of the surface layer burns in the non-halogen, the whole cannot achieve UL94V-0, so that the resist itself is flame retardant (UL94VTM-0).

The printed circuit board manufactured as described above may be connected and mounted with a semiconductor chip by wire bonding or flip chip bonding. After mounting, the wire bonding is sealed with a mold resin composition or a liquid resin composition in a semiconductor plastic package, and in the case of flip chip bonding, an underfill resin is injected between the flip chip and the printed circuit as needed. Harden to complete the product.

2A to 2G schematically show a manufacturing process flow of a printed circuit board according to another exemplary embodiment of the present invention, which will be described with reference to the following.

First, as described above with reference to FIGS. 1A to 1C, a double-sided copper-clad laminate in which copper foils 202 are laminated on both sides of the resin substrate 201 is prepared (see FIG. 2A), and then the holes 203 are processed therein ( 2B) and the copper foil 202 except the uneven part 204 is etched away in the thickness direction, and the buried copper foil layer embedded in the resin substrate 201 is formed (refer FIG. 2C). In FIG. 2B, as an example, a case having a hole diameter of about 50 μm is shown. When the hole is processed, a part of the copper foil is left to partially protrude (see FIG. 2B).

Next, a pattern plating resist 206 such as a dry film is immediately formed on the substrate 201 on which the buried copper foil layer 204 is formed (see FIG. 2D), and an electrolytic pattern using a conventional electrolytic plating method. A copper plating layer 207 is formed (see FIG. 2E). The pattern plating resist 206 is removed (see FIG. 2F), and flash etching is performed as described above in FIG. 1H to remove the buried copper foil layer 204 at the portion where the electrolytic pattern plating layer 207 is not formed, thereby fine circuitry. (See FIG. 2G).

Subsequently, as described above, the subsequent process may be optionally further performed as necessary.

Meanwhile, a manufacturing process flow of the printed circuit board according to Comparative Example 1 of the present invention, which will be described later with reference to FIGS. 3A to 3H, is schematically illustrated.

3A to 3H, first, a double-sided copper-clad laminate in which the copper foil 302 is laminated on both sides of the resin substrate 301 is prepared (see FIG. 3A), and after processing the holes 303 therein (FIG. 3B), copper foil is etched away in the thickness direction so that the thickness of copper foil 302 except the uneven part 304 may be set to 2 micrometers (refer FIG. 3C). Next, the electroless copper plating layer 305 is formed on the substrate 301 obtained therefrom using a conventional electroless plating method (see FIG. 3D), and then a pattern plating resist 306 such as a dry film is formed ( 3E) The electrolytic pattern copper plating layer 307 is formed using a conventional electrolytic plating method (see FIG. 3F). The pattern plating resist 306 is removed (see FIG. 3G), and flash etching is performed to remove the copper foil layers 302, 304, and 305 in the region where the electrolytic pattern plating layer 307 is not formed (FIG. 3h).

As such, when the copper foil 302 except for the uneven portion 304 is not removed, the thickness of the copper foil layer to be removed through flash etching is greater than a certain thickness (for example, 2 μm in the case of Comparative Example 1). As it is relatively thick, as shown in the enlarged part of FIG. 3H, the circuit is rather overetched, so that an undercut occurs.

4A to 4H schematically illustrate a manufacturing process flow of a printed circuit board according to Comparative Example 4 of the present invention.

4A to 4H, first, a double-sided copper foil laminate in which copper foil 402 is laminated on both sides of the resin substrate 401 is prepared (see FIG. 4A). At this time, the uneven portion of the copper foil mat surface embedded in the resin substrate 401 is formed to have a surface roughness Rz of 7.5 μm. Subsequently, after the hole 403 for interlayer electrical conduction is formed in the resin substrate 401 (see FIG. 4B), the copper foil 402 except for the uneven portion 404 is etched away in the thickness direction to fill the embedded copper foil layer 404. ) (See FIG. 4C). Next, the electroless copper plating layer 405 is formed on the substrate 401 obtained therefrom using a conventional electroless plating method (see FIG. 4D), and then a pattern plating resist 406 such as a dry film is applied ( 4E) The electrolytic pattern copper plating layer 407 is formed using a conventional electrolytic plating method (see FIG. 4F). The pattern plating resist 406 is removed (see FIG. 4G), and the flash etching is performed to remove the electroless copper plating layer 405 and the buried copper foil layer 404 in a region where the electrolytic pattern plating layer 407 is not formed. Obtain the circuit (see FIG. 4H).

As such, when the uneven portion 404 of the copper foil mat surface has an excessively large surface roughness (for example, 7.5 μm in the case of Comparative Example 4) outside the range suggested by the present invention, the enlarged portion of FIG. As described above, there is a problem in that all of the copper foil layers 404 of the uneven portions to be removed during the flash etching are not removed. In addition, when the etching time is elongated to completely remove all of the remaining copper foil 404, undercut by over etching occurs.

Hereinafter, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited thereto. Unless otherwise specified in the following Examples and Comparative Examples, "parts" means parts by weight.

Example 1

900 parts of 2,2-bis (4-cyanatephenyl) propane and 100 parts of bis (4-maleimidephenyl) methane were dissolved at 150 ° C and reacted with stirring to obtain a mixture of a prepolymer and a monomer. This was dissolved in a mixed solvent of methyl ethyl ketone and N, N'-dimethyl formamide to obtain varnish A. After adding 500 parts of bisphenol A type epoxy resin (brand name: Epicoat 1001, Japan epoxy resin company) and 500 parts of cresol novolak-type epoxy resin (brand name: ESCN-220F, Sumitomo Chemical Co., Ltd.), it melt | dissolves and mixes uniformly. 0.2 part of zinc octylate was added as a catalyst, it melt | dissolved, it stirred, was mixed uniformly, and Varnish B was obtained. 1300 parts of spherical silicas of 0.6 micrometers of average particle diameters were mix | blended here as an inorganic filler, it was made to stir and mix uniformly, and it was set as varnish C.

The varnish C was impregnated to a glass cloth having a thickness of 20 µm and dried to obtain a prepreg D having a gelation time (at 170 ° C) of 155 seconds and a thickness of 50 µm.

On the other hand, the copper clad laminated board (brand name: CCL-HL832HS, Mitsubishi Gas) which stuck the electrolytic copper foil of thickness 12micrometer which has copper foil mat surface unevenness | corrugation (Rz: 3.2 micrometers) to both sides as size of 300 * 300 mm, thickness 0.4mm as an inner layer board. A hole processing auxiliary material (trade name: LSE30, Mitsubishi Gas Chemical Co., Ltd.) is disposed on the surface of the chemical company, and a hole processing backup material (trade name: LSB90, Mitsubishi Gas Chemical Co., Ltd.) is disposed on the back surface, and the heating roll is heated to 100 ° C. Attached at a pressure of 5 kgf / cm at, and irradiated with a carbon dioxide laser from the surface to form a through hole having a hole diameter of 100 μm, and then peeling off both sides of the hole processing auxiliary material and desmearing the copper foil on both sides after the desmear treatment. After leaving portions, the etching was removed and an electroless copper plating layer was formed thereon at 0.8 mu m. Next, a pattern plating resist was formed, an electrolytic copper plating was formed to a thickness of 22 mu m, the pattern plating resist was removed, and then flash etched to form a circuit of line / space = 20/20 mu m. After applying Mack's CZ treatment to the surface, each of the above-mentioned prepregs D was placed on both sides of the substrate, and a 1.3-micrometer copper copper foil with a copper carrier having a thickness of 35 µm on the outside thereof (trade name: XTF, Olin Brass, Rz: 0.5 4 m substrate E by placing a thermosetting resin composition layer on the surface layer at the same time by laminating and molding for 90 minutes under a vacuum of 190 ° C., 25 kgf / cm 2, and 10 mmHg or less, and filling the inside of the through hole with the thermosetting resin composition. I did it. After peeling the carry copper foil of this surface, the blind via hole of 50 micrometers of hole diameters is opened on both surfaces of this four-layer board | substrate by UV-vanadate laser, and after desmearing, the unevenness | corrugation of the mat surface of copper foil is left and etching and removal is carried out. After the electroless copper plating layer was formed to 0.7 mu m on the entire surface, and a pattern plating resist was formed thereon, the electrolytic copper plating layer was formed to a thickness of 21 mu m and the inside of the blind via hole was filled with copper plating. After the pattern plating resist was removed, flash etching was performed to form a circuit of line / space = 15/15 mu m. This process was repeated to produce a six-layer printed circuit board.

The prepreg D is disposed as a solder resist on the surface layer of the six-layer printed circuit board, a release PET film having a thickness of 25 μm is placed on the surface layer, and laminated molding is performed, and then the release PET film is peeled off. Irradiation was performed to form blind via holes in the flip chip bump pad portion and the solder ball pad portion, followed by desmearing, followed by nickel plating and gold plating to fabricate a six-layer printed circuit board F.

After adhesively connecting a flip chip having a size of 10 mm to a semiconductor chip mounting part in the center of the surface of a printed circuit board having a size of 40 × 40 mm through a lead-free solder reflow furnace, the underfill resin (trade name: CRP4152-D-1, Sumitomo Bakelite Co., Ltd. was poured between the printed circuit board and the semiconductor chip and cured to produce a semiconductor flask package.

The physical property evaluation results of the semiconductor flask package manufactured therefrom are shown in Table 1 below.

Example 2

Double-sided copper-clad laminated board (brand name: E679FG, Hitachi Chemical Co., Ltd.) with 1.3 µm-thick electrolytic copper foil (brand name: XTF, Olin Brass Co., Ltd., mat face irregularities Rz: 0.5 µm) attached to a carrier copper foil having a thickness of 35 µm as an inner layer board. The carrier copper foils of both sides were peeled off, and the through hole of 50 micrometers of hole diameters was formed using UY-YAG laser. After the desmear treatment, the copper foil was etched away after leaving only the unevenness of the mat surface, and then a pattern plating resist was formed thereon, and an electroless copper plating layer was formed on the entire surface of 0.8 µm, and then the electrolytic copper plating layer was formed to have a thickness of 21 µm. At the same time, the inside of the through hole was filled with copper plating. After the pattern plating resist was removed, flash etching was performed to form a circuit of line / space = 15/15 mu m. After applying the CZ surface treatment of Mack company to the surface, each prepreg D of Example 1 is arrange | positioned on both surfaces of this board | substrate, and 1.3 micrometer electrolytic copper foil with a copper carrier of thickness 35micrometer on the outer side (brand name: XTF, Olin Brass, Rz: 0.5 µm) was laminated and molded for 90 minutes under vacuum at 190 ° C, 25 kgf / cm 2, and 10 mmHg or less to obtain a four-layer plate G.

After peeling this carry copper foil of both surfaces, the blind via hole of 50 micrometers of hole diameters is processed on both surfaces of this 4-layer board | substrate with UV-YAG laser, and then it is desmearized and the other copper foil layer except the uneven | corrugated mat surface is etched and removed. It was. After the pattern plating resist was formed thereon, an electroless copper plating layer was formed to have a thickness of 0.7 µm, the electrolytic copper plating layer was formed to have a thickness of 21 µm, and the inside of the blind via hole was filled with copper plating. After the pattern plating resist was removed, flash etching was performed to form a circuit of line / space = 12/12 mu m. After the CZ treatment, a liquid crystal polyester resin composition sheet having a melting point of 285 ° C. at a thickness of 40 μm was placed on the surface thereof, and an electrolytic copper foil having a thickness of 1.3 μm with the carrier copper foil was placed on the outside thereof. After laminating for 20 minutes under a vacuum of mmHg or less, the carrier copper foil was peeled off, and then the remaining copper foil layer except for the uneven portion of the copper foil was etched and removed, followed by the formation of a pattern plating resist, the formation of an electroless copper plating layer, and an electrolytic copper plating layer. Forming, pattern plating resist stripping, and flash etching were performed as described above to form a circuit to fabricate a six-layer printed circuit board.

The circuit of the surface layer of this printed circuit board was subjected to CZ treatment, a liquid crystal polyester resin composition sheet having a melting point of 275 ° C. at a thickness of 30 μm was placed, and a 25 μm thick Teflon release film was placed on the outside thereof. It laminated | stacked for 20 minutes under the vacuum of kgf / cm <2> and 5 mmHg or less, and set it as the soldering resist layer. After forming the bump pad part of the surface layer and the solder ball pad part of this surface by the carbon dioxide laser, nickel plating and gold plating were performed after plasma processing, and the six-layer printed circuit board H was produced.

After adhesively connecting a flip chip having a size of 10 mm to a semiconductor chip mounting part in the center of the surface of a printed circuit board having a size of 40 × 40 mm through a lead-free solder leaf furnace, the underfill resin of Example 1 was connected to the printed circuit board. And the flip chip was poured between the cured to produce a semiconductor plastic package.

The physical property evaluation results of the semiconductor flask package manufactured therefrom are shown in Table 1 below.

Comparative Example 1

The same double-sided copper-clad laminate as in Example 1 was used, but the copper foils on both sides were etched and etched and removed so that the thickness of the copper foil except for the uneven portion was 2 μm, and then a through hole having a hole diameter of 100 μm was formed therein using a CNC drill. After the desmear treatment, 0.7 µm of the electroless copper plating layer and 15 µm of the electrolytic copper plating layer were formed. The circuit board of the line / space = 20 / 20micrometer was formed by the subtractive method, and the circuit board was produced. In this case, peeling of the circuit appeared. Further etching proceeded to show an extremely thin circuit at the top of the circuit.

For this reason, after manufacturing the circuit board which formed the circuit of the line / space = 30/30 micrometer, CZ process is carried out, and the semi-additive resin composition sheet (brand name: ABF GX-3, Ajinomoto Co., Ltd.) of 50 micrometers in thickness is formed on this. One sheet was placed and adhered to the circuit board for 1 minute under a vacuum of 5 mmHg or less at a pressure of 100 ° C. and 5 kgf / cm 2, and then the PET film was peeled off and placed in an oven at a temperature of 100 ° C. for 30 minutes at a temperature of 170 ° C. After curing for 30 minutes at, blind via holes having a hole diameter of 50 μm were formed with a UV-YAG laser and desmeared. An electroless copper plating layer was formed on the entire surface, and a pattern plating resist was formed thereon, and then the inside of the blind via hole was filled with copper plating while forming an electrolytic copper plating layer having a thickness of 21 μm. After the pattern plating resist was removed, a circuit of line / space = 15/15 탆 was formed by flash etching and post-cured at 170 ° C. for 60 minutes. This process was repeated to produce a six-layer printed circuit board.

The circuit of the surface layer of this printed circuit board was subjected to CZ treatment, and a liquid UV selective thermosetting solder resist (trade name: PSR4000AUS5, manufactured by Taiyo Inc.) was coated, dried, exposed and developed to a thickness of 20 µm on a copper foil, and then flip-chip connected. After the lands were formed, a six-layer printed circuit board I was fabricated by nickel plating and gold plating.

Thereafter, the flip chip was connected in the same manner as in Example 1, and the underfill resin was poured between the printed circuit board and the flip chip and cured to form a semiconductor plastic package.

The physical property evaluation results of the semiconductor flask package manufactured therefrom are shown in Table 1 below.

Comparative Example 2

In Comparative Example 1, the inner layer material was used as it was, and was formed to have a thickness of 25 μm using a resin composition for forming a UV via (trade name: IDL-322, JSR Co., Ltd.) as a build-up substrate, and developed after UV irradiation. A blind via hole having a diameter of 50 mu m was formed, desmeared, and the circuit formation process of flash etching after copper plating as described above was repeated to obtain a six-layer printed circuit board.

Subsequently, a UV selective thermosetting solder resist (precious metal plating resist) of Comparative Example 1 was formed, and precious metal plating was performed to obtain a printed circuit board. The flip chip was connected, and the underfill resin was poured between the printed circuit board and the flip chip and cured to form a semiconductor plastic package.

The physical property evaluation results of the semiconductor flask package manufactured therefrom are shown in Table 1 below.

Comparative Example 3

In Example 2, after the 70-micrometer through-hole process, all copper foils were etched away without leaving copper of the copper foil mat surface uneven | corrugated part, and after performing a desmear process, an electroless copper plating layer 0.7 micrometer is formed and a pattern plating resist is apply | coated, After that, 21 µm of an electrolytic copper plating layer was formed. The pattern plating resist was peeled off and flash etched to form a circuit. At this time, the circuit was partially peeled off. CZ treatment was carried out, and one piece of prepreg having a thickness of FR-5, which was flame retarded with bromine, was placed on each sheet, and an electrolytic copper foil (mat surface Rz: 3.0 µm) of 12 µm was placed thereon, and 170 ° C. The inside of the through hole was filled with a resin composition while curing was performed under vacuum of 25 kgf / cm 2 and 5 mmHg or less for 30 minutes. All copper foils on the surface were etched away, and a blind via hole having a hole diameter of 50 µm was opened in this resin composition with a UV-YAG laser, and after desmearing, 0.7 µm of an electroless copper plating layer was formed on the entire surface. After the formation, the electrolytic copper plating layer was formed to a thickness of 21 μm, and the inside of the blind via hole was filled with copper plating. After the pattern plating resist was removed, a circuit of line / space = 15/15 mu m was formed by flash etching and post-cured at 180 ° C. for 60 minutes. This process was repeated to produce a six-layer printed circuit board. The prepreg of FR-5 was weak in the copper circuit adhesion force at the time of lamination | molding, and partly peeled by the resin composition flow at the time of lamination | stacking. The UV selective thermosetting resist of the comparative example 1 was formed on this, and nickel plating and gold plating were performed, and it was set as the printed circuit board.

The physical property evaluation results of the semiconductor flask package manufactured therefrom are shown in Table 1 below.

Comparative Example 4

A printed circuit board was produced in the same manner as in Example 1, except that Rz of the mat surface of the copper foil of the double-sided copper-clad laminate was 7.5 µm. In this case, when the circuit of line / space = 20/20 micrometers was formed, if the etching was the same conditions, the unevenness | corrugation of the edge part of the copper foil mat surface remained between circuits. Further, if the etching proceeds further, an undercut of the circuit occurs and a circuit having a uniform shape cannot be obtained.

Comparative Example 5

A printed circuit board was produced in the same manner as in Example 1 except that Rz of the mat surface of the copper foil of the double-sided copper-clad laminate was used at 0.12 μm. In this case, when the circuit of line / space = 20/20 micrometers was formed, all the circuits of the 40 * 40mm printed circuit board within 300x300mm of work size peeled, and 100% defect was made.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5  (1) Stripping copper circuits when building up materials none none none none has exist has exist -  (2) Deterioration of copper circuit in process none none none none has exist has exist has exist  (3) Line / Space of Inner Layer Substrate = 20 / 20㎛ Circuit Formation Good Good Defect Defect Defect Defect Defect  (4) Warping and skewing (㎛) Printed circuit board 88 102 228 370 157 After FC 112 135 331 670 302 After underfill 91 107 310 603 269  (5) Copper Adhesion (kgf / cm) Inner Layer Substrate 0.73-0.83 0.76-0.79 0.79-0.83 0.79-0.83 0.18-0.26 Build up layer 0.77-0.80 0.80-0.82 0.75-0.81 0.65-0.69 0.22-0.28  (6) Heat resistance after moisture absorption (n / 100) 0/100 0/100 47/100 89/100 12/100  (7) Chemical resistance weight change rate (%) HCl 20% -0.2 -0.1 -2.9 -3.1 -2.1 NaOH 10% -0.5 -0.3 -5.9 -7.5 -3.9  (8) Transmission loss (dB) at 25 GHz -8 -3 -22 -39 -25  (9) migration resistance Inner Board Circuit condition 5 × 10 ¹³ 7 × 10 ¹³ 6 × 10 ¹³ 5 × 10 ¹³ 5 × 10 ¹³ 200 hours 7 × 10 ¹⁰ 5 × 10 ¹⁰ 1 × 10 ¹⁰ 6 × 10 ⁹ 3 × 10 ¹⁰ 600 hours 2 × 10 ¹⁰ 1 × 10 ¹⁰ 3 × 10 ⁸ <10 ⁸ <10 ⁸ Outermost circuit condition 6 × 10 ¹³ 6 × 10 ¹³ 7 × 10 ¹³ 5 × 10 ¹³ 6 × 10 ¹³ 200 hours 5 × 10 ¹⁰ 1 × 10 ¹⁰ 1 × 10 ¹⁰ 6 × 10 ⁹ 3 × 10 ¹⁰ 600 hours 3 × 10 ¹⁰ 4 × 10 ⁹ <10 ⁸ <10 ⁸ <10 ⁸

<Measurement method>

(1) Stripping of copper circuit when building up board

When the build-up substrate material was laminated on the inner layer printed circuit board on which the circuit was formed, peeling of the inner layer substrate circuit was observed.

(2) Deterioration of copper circuit in process

The defect was seen after the 100-sheet process with a working size of 300 x 300 mm. In the case of the process, it was checked whether there was a defect in the whole process.

(3) Line / Space of Inner Layer Substrate = 20 / 20㎛ Circuit Formation

After forming the circuit of the line / space = 20 / 20㎛ in the inner layer substrate was checked for defects.

(4) warping and skewing

Printed circuit board size was measured at 40 × 40 mm. Printed circuit board alone, with a 10 mm size flip chip mounted in the center with lead-free solder reflow (up to 260 ° C), and the maximum warpage and skew when the underfill resin is filled and cured Measured accordingly.

(5) Copper adhesion

Copper adhesion on the inner layer board and the buildup layer was measured. It measured according to JIS C6481.

(6) heat resistance

After making 100 printed circuit boards each and performing them for 3 hours after a super accelerated life test (PCT: 121 ° C, 2.1 atm), they are immersed in a solder bath at 260 ° C for 30 seconds, and the substrate is swollen and peeled off. Observed. The number of occurrences of swelling and peeling was described in the molecule, and the number of tests was described in the denominator.

(7) chemical resistance

The copper foils on the surface were all etched without using the surface solder resist (noble metal plating resist), and the test piece of 40 × 40 mm was immersed in a 20% HCl and 20% NaOH solution at 25 ° C. for 1 hour and washed with water. After drying at 125 ° C. for 24 hours, the weight was measured to indicate how much the weight changed from the beginning.

(8) transmission loss

The outermost microstrip line was fabricated with an insulation layer thickness of 50 ± 7 μm, a line width of 25 ± 5 μm, and a line thickness of 20 ± 4 μm, and the transmission loss to 25 GHz was measured.

(9) migration resistance

Migration resistance between inner layer circuits and outermost layer circuits was measured.

The circuit was measured at line / space = 30/30 μm. The insulation resistance value after a predetermined time with a voltage of 70 VDC was applied.

As described above, the high-density printed circuit board manufactured according to the present invention has good adhesion between the copper plated copper layer, excellent reliability between circuits and insulation layers of the build-up resin composition layer, heat resistance after moisture absorption, chemical resistance, and the like. It is small in warping and skewing, and can be used for high frequency applications.

Although the present invention has been described in detail through specific embodiments, this is for explaining the present invention in detail, and the high-density printed circuit board and its manufacturing method according to the present invention are not limited thereto and within the technical spirit of the present invention. It is apparent that modifications and improvements are possible by those skilled in the art.

All simple modifications and variations of the present invention fall within the scope of the present invention, and the specific scope of protection of the present invention will be apparent from the appended claims.

Claims (8)

Resin substrates; And A pattern circuit layer formed on both sides of the resin substrate; Including; The pattern circuit layer is a buried copper foil layer formed by embedding an uneven portion of a copper foil mat surface having a surface roughness Rz of 0.2-7 μm on a resin substrate, an electroless copper plating layer formed on the buried copper foil layer, and the A printed circuit board comprising an electrolytic copper plating layer formed on the electroless copper plating layer. Resin substrates; And A pattern circuit layer formed on the resin substrate; Including; The pattern circuit layer includes a buried copper foil layer formed by embedding an uneven portion of a copper foil mat surface having a surface roughness Rz of 0.2-7 μm on a resin substrate, and an electrolytic copper plating layer formed on the buried copper foil layer. Printed circuit board. The printed circuit board according to claim 1 or 2, wherein the uneven portion of the copper foil mat surface has a surface roughness Rz of 0.3 to 5 mu m. (a) providing a double-sided copper foil laminated plate formed by laminating copper foils so that uneven parts of a copper foil mat surface having a surface roughness Rz of 0.2 to 7 μm are embedded on both sides of a resin substrate; (b) forming a buried copper foil layer by etching copper foil in a thickness direction except for the buried uneven parts; (c) forming an electroless copper plating layer on the substrate on which the buried copper foil layer is formed; (d) forming an electrolytic pattern copper plating layer on the electroless copper plating layer; And (e) removing the electroless copper plating layer and the buried copper foil layer of the portion where the electrolytic pattern copper plating layer is not formed; Method of manufacturing a printed circuit board comprising a. (a) providing a double-sided copper foil laminated plate formed by laminating copper foils so that uneven parts of a copper foil mat surface having a surface roughness Rz of 0.2 to 7 μm are embedded on both sides of a resin substrate; (b) forming a buried copper foil layer by etching copper foil in a thickness direction except for the buried uneven parts; (c) forming an electrolytic pattern copper plating layer on the substrate on which the buried copper foil layer is formed; And (d) removing the buried copper foil layer at the portion where the electrolytic pattern copper plating layer is not formed; Method of manufacturing a printed circuit board comprising a. 6. The printed circuit according to claim 4 or 5, wherein the method further comprises forming via holes for interlayer electrical conduction in the resin substrate before the step (b) or after the step (b). Method of manufacturing a substrate. The method of manufacturing a printed circuit board according to claim 4 or 5, wherein the thickness of the copper foil etched in the step (b) is 5 µm or less. The method of manufacturing a printed circuit board according to claim 4 or 5, wherein the uneven portion of the copper foil mat surface has a surface roughness Rz of 0.3 to 5 탆.

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