JP2004281483A - Wiring circuit board and method of manufacturing the same, and connection structure between the wiring circuit board and electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring circuit board in which excellent connection reliability between a connection terminal formed as one part of a conductor wiring pattern and an external terminal can be ensured, even if the conductor wiring pattern is formed by plating at fine pitch, and to provide a method of manufacturing the wiring circuit board and a connection structure between the wiring circuit board and an electronic component. <P>SOLUTION: The conductor wiring pattern is formed on a base insulating layer 1 by plating so as to be formed by a plurality of wirings 5 each having a shape in which a center 7 rises against both side ends 8 of a widthwise direction, and the connection terminals 5 are connected to bump electrodes of a semiconductor element. Since the center 7 of the connection terminal 5 sinks to the bump electrode before both side ends 8, expansion of the bump electrodes in a widthwise direction can be suppressed, and generation of short circuit between the respective adjacent bump electrodes can be effectively prevented. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a printed circuit board and a method of manufacturing the same, and a connection structure between the printed circuit board and an electronic component.
[0002]
[Prior art]
2. Description of the Related Art In recent years, with the miniaturization and high performance of electronic components, conductor wiring patterns of printed circuit boards on which electronic components are mounted have become finer and higher in density.
[0003]
Conventionally, as a method of patterning a printed circuit board, a subtractive method, an additive method, a semi-additive method, and the like are known.
[0004]
In the subtractive method, for example, first, a conductor layer is laminated on the surface of the base insulating layer, then an etching resist is formed as a pattern corresponding to the conductor wiring pattern, and then the conductor layer is formed by using the etching resist as a resist. The conductor wiring pattern is formed by etching.
[0005]
However, in the subtractive method, as shown in FIG. 6, each of the wirings 23 of the conductor wiring pattern 22 has a substantially trapezoidal shape in which the bottom surface (the interface with the base insulating layer 21) is wider than the top by etching. For example, when the fine pitch is formed at a fine pitch of 60 μm or less, there is a limit to the fine pitch, for example, the etching resist 24 is peeled off due to over-etching.
[0006]
On the other hand, in the additive method and the semi-additive method, for example, a plating resist is formed as a reverse pattern of a conductor wiring pattern on the surface of a base insulating layer, and then a conductor wiring pattern is formed between the plating resists by plating. (For example, see Patent Document 1).
[0007]
In such an additive method or a semi-additive method, as shown in FIG. 7, each wiring 23 of the conductor wiring pattern 22 is formed in a substantially rectangular cross section by plating, so that the top surface of each wiring 23 is subtracted. It can be formed wider than by patterning by a method, and can respond to fine pitching.
[0008]
Then, when a part of the conductor wiring pattern 22 formed by the additive method or the semi-additive method in this way becomes a connection terminal for directly connecting to an external terminal, as shown in FIG. When the connection terminals 23 are connected to the external terminals 26 of the liquid crystal glass substrate 25 via the anisotropic conductive film or the anisotropic conductive paste 27, the connection terminals 23 are sandwiched between the external terminals 26 and the connection terminals 23. Since the number of conductive particles 28 of several μmφ level increases and the chance of contact increases, it is advantageous for electrical connection reliability.
[0009]
[Patent Document 1]
JP-A-8-45213
[Problems to be solved by the invention]
However, as shown in FIG. 9, when the bump electrode 30 provided on the semiconductor element 29 and made of a soft metal such as solder or gold is connected to the connection terminal 23, the bump electrode 30 is connected to the connection terminal 23. Of the connection terminals 23, the adjacent bump electrodes 30 are short-circuited because the top surfaces of the connection terminals 23 are wide.
[0010]
An object of the present invention is to ensure good connection reliability between a connection terminal formed as a part of the conductor wiring pattern and an external terminal even when the conductor wiring pattern is formed at a fine pitch by plating. The present invention provides a printed circuit board, a method of manufacturing the printed circuit board, and a connection structure between the printed circuit board and an electronic component.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a wired circuit board of the present invention is a wired circuit board provided with a conductor wiring pattern, and a part of the conductor wiring pattern serves as a connection terminal for connecting to an external terminal. As described above, the connection terminal is formed such that the thickness of the connection terminal is thicker at the center in the width direction than at both side ends in the width direction orthogonal to the longitudinal direction of the connection terminal. It is characterized by being.
[0012]
Further, in the wired circuit board of the present invention, in the connection terminal, it is preferable that a difference in thickness between both end portions in the width direction and a center portion in the width direction is 2 μm or more. A plurality of connection terminals are provided in the width direction, and the pitch between the connection terminals is preferably 60 μm or less.
[0013]
Further, in the wired circuit board of the present invention, it is preferable that the connection terminal is formed in a cross-sectional shape in the width direction such that a central portion rises with respect to both side end portions.
[0014]
Also, the present invention provides a step of preparing an insulating layer, a step of forming a plating resist on the insulating layer in a pattern that is the reverse of the conductive wiring pattern, and plating the conductive wiring pattern between the plating resists. A step of forming a conductor wiring pattern, in which a plurality of wirings whose center portions in the width direction are thicker are formed with respect to both side ends in the width direction orthogonal to the longitudinal direction of the conductor pattern, and removing the plating resist And a method for manufacturing a printed circuit board.
[0015]
Also, the present invention provides an electronic device, wherein an external terminal provided on the electronic component is connected to the connection terminal of the printed circuit board such that the connection terminal digs into the external terminal and swells in a width direction of the connection terminal. The connection structure between the printed circuit board and the electronic component.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a process chart showing one embodiment of a method for manufacturing a printed circuit board according to the present invention.
[0017]
First, in this method, as shown in FIG. 1A, an insulating base layer 1 is prepared as an insulating layer. The base insulating layer 1 is not particularly limited, and a material usually used as a base insulating layer of a printed circuit board is used. For example, thermoplastic resin such as polyester resin, polyethylene resin, polystyrene resin, polycarbonate resin, polyamide resin, polyimide resin, urethane resin, ABS resin, epoxy resin, fluorine resin, silicone resin or A thermosetting resin or the like is used. Further, in order to impart strength to the base insulating layer 1, the composite may be formed by adding a reinforcing material such as a filler, a glass fiber, or a nonwoven fabric to the thermoplastic resin or the thermosetting resin.
[0018]
In addition, the thickness of the insulating base layer 1 is preferably 5 μm or more from the viewpoint of mechanical properties and electrical insulation. When flexibility is required, it is preferably 500 μm or less.
[0019]
Next, in this method, a conductive thin film 2 is formed on the base insulating layer 1 as shown in FIG.
[0020]
The formation of the conductive thin film 2 is not particularly limited, and a method usually used in a semi-additive method can be used. For example, a deposition method such as a vacuum deposition method, an ion plating method, and a sputtering method, for example, an electroless method A plating method or the like is used. Of these, the sputtering method is preferably used. Further, the conductor forming the conductive thin film 2 is not particularly limited, and for example, Ni, Cr, Cu, Ni / Cr alloy, Cu / Ni alloy, Ti, and alloys thereof are used. The thickness of the conductive thin film 2 is, for example, 0.01 μm or more and 0.5 μm or less. In addition, the conductive thin film 2 can be formed as two or more layers.
[0021]
In actual production, the base insulating layer 1 on which the conductive thin film 2 is formed in advance may be prepared by obtaining a commercially available product.
[0022]
Next, in this method, as shown in FIG. 1C, a plating resist 3 is formed on the conductive thin film 2 in a reverse pattern of the conductor wiring pattern 4.
[0023]
The formation of the plating resist 3 is not particularly limited, and a method usually used in a semi-additive method can be used. For example, a photographic method or a printing method is used. Of these, the photographic method is preferably used, and more specifically, for example, using a dry film resist having an electrolytic plating solution resistance, a photo processing method in which exposure and development are performed, and the like, as a resist pattern. Can be formed.
[0024]
In this method, as shown in FIG. 1D, a conductive wiring pattern 4 is formed by electroplating on a portion of the conductive thin film 2 where the plating resist 3 is not formed.
[0025]
Although the conductor wiring pattern 4 is not particularly limited, for example, as shown in FIG. 2, a large number of wirings 5 are patterns arranged in parallel at predetermined intervals along the longitudinal direction. It can be formed as a pattern of any shape.
[0026]
Further, in this method, one end of each of the wirings 5 of the conductor wiring pattern 4 in the longitudinal direction is connected to a bump terminal 14 as an external terminal of a semiconductor element 13 as an electronic component described later. 6 is assumed.
[0027]
Further, the pitch of each wiring 5 in such a conductive wiring pattern 4 (the width of the wiring 5 + the gap between the wirings 5), more specifically, the pitch of each connection terminal 6 (the bottom surface 9 of the connection terminal 6) The width + the gap between the bottom surfaces 9 of the connection terminals 6 (see FIG. 3) P is formed at a fine pitch of, for example, 60 μm or less.
[0028]
Further, the metal forming the conductive wiring pattern 4 is not particularly limited, but for example, copper, nickel, chromium, iron, tin, lead, aluminum, and alloys thereof are used. Preferably, copper or a copper alloy is used.
[0029]
The thickness of the conductive wiring pattern 4 (the thickness Ta from the bottom surface 9 to the central portion 7 described later; see FIG. 3) is, for example, 3 μm or more and 50 μm or less, preferably 5 μm or more and 20 μm or less. If the thickness of the conductor wiring pattern 4 is less than 3 μm, as described later, even if the bump electrode 14 first contacts the central portion 7 in the width direction of the connection terminal 6, when the bump electrode 14 is pressed, the bump electrode 14 will 6 may contact the base insulating layer 1 on both sides, and may not be able to suppress the spread of the bump electrode 14 in the width direction. On the other hand, if it exceeds 50 μm, it may not be possible to form a fine pitch of, for example, 60 μm or less due to the limitation of the resolution of the plating resist 3.
[0030]
Next, in this method, the plating resist 3 is removed as shown in FIG. The removal of the plating resist 3 is not particularly limited, and a method usually used in a semi-additive method can be used. For example, a stripping method using a stripping solution such as an alkali stripping solution, a chemical etching (wet etching) or the like can be used. An etching method is used.
[0031]
Thereafter, in this method, as shown in FIG. 1 (f), the conductive thin film 2 corresponding to the portion where the plating resist 3 was formed is removed, thereby obtaining the printed circuit board 10. The removal of the conductive thin film 2 is not particularly limited, and a method usually used in a semi-additive method can be used. For example, a known etching such as a chemical etching (wet etching) using an etching solution such as an acid etching solution can be used. Method is used.
[0032]
In this method, as shown in FIG. 3, the thickness of each wiring 5 (including each connection terminal 6) of the conductor wiring pattern 4 is set in the width direction of the conductor wiring pattern 4 (the direction orthogonal to the longitudinal direction). The central portion 7 in the width direction is formed to be thicker than the both end portions 8.
[0033]
More specifically, each wiring 5 (including each connection terminal 6) has a rounded arc shape or a spindle shape in which a central portion 7 rises in a cross-sectional shape in the width direction, and each wiring 5 (each connection terminal 6). Is formed as a uniform thickness, and the difference ΔT between the thickness Tb of both end portions 8 in the width direction and the thickness Ta of the central portion 7 in the width direction is 2 μm or more, preferably 4 μm or more. Usually, it is formed so as to be 50 μm or less. If the thickness difference ΔT is less than 2 μm, the spread of the bump electrode 14 in the width direction may not be suppressed as described later.
[0034]
As shown in FIG. 3, both end portions 8 in the width direction are outermost side edges in the width direction of each wiring 5 (including each connection terminal 6), and a central portion 7 in the width direction. Is an upper edge facing the center between the both side end portions 8 in the thickness direction.
[0035]
Thus, the width of each wiring 5 (including each connection terminal 6) gradually or in the thickness direction from the bottom surface 9 in contact with the base insulating layer 1 to the central portion 7 (upper edge) at the center in the width direction. It is formed as a rounded shape that becomes gradually narrower in the middle.
[0036]
The central portion 7 may be formed to be flat, but in this case, at least the width of the central portion 7 is formed to be smaller than the width of the bottom surface 9.
[0037]
As described above, in order to form each wiring 5 (including each connection terminal 6) such that the thickness Ta of the central portion 7 is thicker than the thickness Tb of the both end portions 8, an additive of a plating solution in electrolytic plating That is, selection of the component ratio of the accelerator and the smoothing agent, stirring fluidity of the plating solution (for example, supplying the plating solution so that the flowing solution is perpendicular to the surface to be plated), current conditions, and dummy. A method of controlling the electric field in the vicinity of the plating deposition by forming an electrode or the like can be realized by adopting the method alone or in combination.
[0038]
That is, when the pitch of each wiring 5 (including each connection terminal 6) is reduced (that is, the interval between the plating resists 3 is reduced), the supply of precipitated metal ions to the exposed conductive thin film 2, The supply of additives such as accelerators and leveling agents is reduced.
[0039]
In particular, the supply of the above components is reduced to the corners of the wiring 5 (including the connection terminal 6) formed by the wall surface of the plating resist 3 and the conductive thin film 2. Therefore, the balance between the plating promotion and the suppression effect is balanced by the component ratio of the accelerator and the smoothing agent, and the plating growth is promoted in the central portion 7 rather than the both end portions 8 or the plating growth of the both end portions 8 is promoted. By obstructing, the wiring 5 (including the connection terminal 6) can be provided with a thickness difference.
[0040]
For example, in the preparation of an electrolytic copper plating solution, a soluble copper salt such as copper sulfate, and a sulfate-containing compound such as a thiourea or a derivative thereof, etc. In addition, as a leveling agent, for example, an azo dye, an amide compound, a thioamide compound, a nitrogen-containing compound such as an aniline or a compound having a pyridine ring, and the like are added at an appropriate ratio.
[0041]
Further, if a polymer surfactant such as polyethylene glycol, polyvinyl alcohol and carboxymethyl cellulose is blended in an appropriate ratio, the deposition of plating can be controlled.
[0042]
Thereafter, by supplying metal ions of the plating solution efficiently, each wiring 5 (including each connection terminal 6) having the above-mentioned shape can be formed uniformly.
[0043]
In addition, the printed circuit board 10 obtained in this manner may be formed by laminating a solder resist or a cover insulating layer by a known method, if necessary, to protect the conductor wiring pattern 4 or to laminate a reinforcing plate. May be.
[0044]
The printed circuit board 10 thus obtained is used without any limitation in its use, and is suitably used, for example, as a tape carrier as shown in FIG.
[0045]
That is, in FIG. 2, a cover insulating layer 12 having an opening 11 opened in a substantially rectangular shape is formed on the base insulating layer 1 including the conductor wiring pattern 4. The connection terminal 6 formed as a part of the wiring pattern 4 is exposed. As shown in FIG. 4, a semiconductor element 13 is mounted on the opening 12, and a bump electrode 14 of the semiconductor element 13 is connected to the connection terminal 6.
[0046]
The cover insulating layer 12 can be formed by, for example, using the same material as the above-described base insulating layer 1 and drying or curing the resin solution after application. Further, the opening 11 can be formed by, for example, drilling, punching, etching, patterning by exposing and developing a photosensitive resin, and the like.
[0047]
Next, the connection structure between the printed circuit board and the electronic component according to the present invention will be described with reference to FIG. 4, in which the bump electrode 14 of the semiconductor element 13 is connected to the connection terminal 6 of the printed circuit board 10. To explain.
[0048]
In FIG. 4, the bump electrodes 14 of the semiconductor element 13 are made of a soft metal such as solder or gold, for example, and a plurality of bump electrodes 14 are provided in the semiconductor element 13 corresponding to the connection terminals 6.
[0049]
Then, the semiconductor element 13 is arranged in the opening 11, and each bump electrode 14 is pressed against each connection terminal 6 from above, in a facing manner. Then, the central portion 7 of each connection terminal 6 sinks into each bump electrode 14, and the connection is made so that each bump electrode 14 swells in the width direction. In addition, it is preferable that the indentation is, for example, 1 μm or more, more preferably 2 to 10 μm, as the depth D of the depression of the bump electrode 14. If it is less than 1 μm, the electrical connection may be insufficient. If it exceeds 10 μm, the width of the bump electrodes 14 in the width direction becomes too large, and a short circuit occurs between the adjacent bump electrodes 14. There are cases.
[0050]
In such a connection structure, in each connection terminal 6, the center portion 7 is formed thicker than the both end portions 8, and the center portion 7 is connected to the bump electrode 14 before the both end portions 8 at the time of connection. Since the connection is performed so as to be recessed, the spread of the bump electrode 14 in the width direction can be suppressed, and the degree of swelling of the bump electrode 14 in the width direction can be reduced. Therefore, even if the conductor wiring patterns 4 are formed at a fine pitch of, for example, 60 μm or less, it is possible to effectively prevent the occurrence of a short circuit between the adjacent bump electrodes 14, and to connect the bump electrodes 14 to the connection terminals 6. Of the connection can be improved.
[0051]
In the above description, the printed circuit board 10 is formed by the semi-additive method. However, the method of manufacturing the printed circuit board of the present invention is not particularly limited, and may be formed by, for example, the additive method.
[0052]
In the additive method, first, similarly to the above, a base insulating layer 1 is prepared, and a plating resist 3 is formed on the base insulating layer 1 with an inverted pattern of a conductor wiring pattern 4 without forming a conductive thin film 2. After that, the conductive wiring pattern 4 is formed by electroless plating on the portion of the base insulating layer 1 where the plating resist 3 is not formed, in the same manner as described above. The wirings 5 are formed such that a plurality of wirings 5 are formed in parallel.
[0053]
The printed circuit board of the present invention can also be formed as a multilayer printed circuit board by laminating a separately manufactured printed circuit board on the printed circuit board manufactured as described above.
[0054]
【Example】
Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
[0055]
Example 1
A base insulating layer 1 made of a polyimide film (upilex manufactured by Ube Industries) having a thickness of 25 μm is prepared (see 1 (a)), and a conductive thin film 2 made of Ni / Cu having a thickness of 500 ° is formed on the base insulating layer 1. , Formed by sputtering (see FIG. 1B). Next, a plating resist 3 made of a photosensitive dry film resist (SFG152, manufactured by Asahi Kasei Corporation, 15 μm in thickness) is adhered on the conductive thin film 2 by lamination, and the conductor wiring pattern 4 is inverted by exposure and development. A pattern (line width 15 μm / gap between lines 20 μm) was formed (see FIG. 1C).
[0056]
Thereafter, a portion of the conductive thin film 2 where the plating resist 3 is not formed is electrolytically copper-plated to form a conductor wiring pattern 4 (width of the wiring 5 20 μm / gap 15 μm between the wirings 5) (FIG. 1 ( d)).
[0057]
Electrolytic copper plating is 200g / L CuSO ₄ ・ 5H ₂ O, a base solution containing 60 g / L concentrated sulfuric acid and 17 mL / L hydrochloric acid was mixed with 100 mg / L polyethylene glycol and 10 mg / L bis-3-sulfopropyl disulfide disodium (SPS) to obtain a mixture. The plating solution was applied at 2.0 A / dm 2 such that the flowing solution was vertically applied to the surface of the conductive thin film 2 between the reverse patterns of the plating resist 3. ² For 18 minutes to form a film having a thickness of 8 μm.
[0058]
Thereafter, the plating resist 3 is removed with an alkaline solution (see FIG. 1 (e)), and then the conductive thin film 2 is removed with a hydrochloric acid acidic chemical to obtain a printed circuit board 10 (FIG. 1 ( f)).
[0059]
Each of the wirings 5 of the conductor wiring pattern 4 of the obtained wiring circuit board 10 has a rounded arc shape in which the central portion 7 rises with respect to the both end portions 8 in the cross-sectional shape in the width direction. The thickness difference ΔT from the central portion 7 was 4 μm.
[0060]
Then, one end of each wiring 5 of the printed circuit board 10 is used as a connection terminal 6, and a bump electrode 14 made of gold having a thickness of 15 μm of the semiconductor element 13 is inserted into the connection terminal 6, and the connection terminal 6 is inserted into the bump electrode 14. , So that the bump electrode 14 is depressed by 3 μm. Thereafter, the connection between each connection terminal 6 and each bump electrode 14 was confirmed, but no short circuit occurred between the adjacent bump electrodes 14.
[0061]
Example 2
A two-layer base material 16 (Espanex, manufactured by Nippon Steel Chemical Co., Ltd.) in which a metal layer 15 made of a copper foil with a thickness of 18 μm and a base insulating layer 1 made of a polyimide film with a thickness of 12 μm are laminated is prepared ( Referring to FIG. 5 (a), a blind hole 17 having a diameter of 100 μm is formed in the base insulating layer 1 of the two-layer substrate 16 by a YAG laser so that the metal layer 15 is exposed from the surface thereof in the thickness direction. (See FIG. 5B).
[0062]
Next, a conductive thin film 2 was formed on the base insulating layer 1 by sequentially sputtering Cr having a thickness of 400 ° and Cu having a thickness of 2000 ° (see FIG. 5C).
[0063]
Thereafter, a plating resist 3 made of a photosensitive dry film resist (SFG252, manufactured by Asahi Kasei Corporation, thickness 25 μm) is attached to both surfaces of the two-layer substrate 16 by lamination, and only the side on which the conductive thin film 2 is formed is formed. Then, an inverted pattern of the conductor wiring pattern 4 (line width 25 μm / gap between lines 25 μm) was formed by exposure and development (see FIG. 5D).
[0064]
Thereafter, a portion of the conductive thin film 2 where the plating resist 3 is not formed is subjected to electrolytic copper plating to form a conductor wiring pattern 4 including the dummy electrode 18 (width of the wiring 5 25 μm / gap 25 μm between the wirings 5). (See FIG. 5E).
[0065]
Electrolytic copper plating is 200g / L CuSO ₄ ・ 5H ₂ O, 100 mg / L polyethylene glycol, 5 mg / L bis-3-sulfopropyl disulfide disodium (SPS), 0.6 mg / L in a base solution containing 60 g / L concentrated sulfuric acid and 17 mL / L hydrochloric acid. The plating solution obtained by blending 2,2′-bipyridyl in 2.5 A / dm 2 was applied so that the flowing solution was vertically applied to the surface of the conductive thin film 2 between the reversal patterns of the plating resist 3. ² For 25 minutes to form a film having a thickness of 12 μm.
[0066]
Thereafter, the plating resist 3 is removed with an alkaline solution (see FIG. 5 (f)). Then, the conductive thin film 2 is removed by sequentially etching the Cu layer with a sodium persulfate solution and the Cr layer with a potassium ferricyanide solution. (See FIG. 5 (g)).
[0067]
Each of the wirings 5 of the conductor wiring pattern 4 thus formed has a rounded arc shape in which the central portion 7 rises with respect to the both end portions 8 in the cross-sectional shape in the width direction, and the both end portions 8 and the central portion 7 are formed. Was 5 μm.
[0068]
Next, a photosensitive dry film resist is stuck on both sides by lamination, exposed and developed, and then etched with a ferric chloride solution to form only the metal layer 15 into a conductive wiring pattern. By removing the resist, a double-sided wiring board was formed (see FIG. 5H).
[0069]
Thereafter, electroless Sn plating having a thickness of 0.7 μm was applied to the surface of the conductor wiring pattern 4 formed by electrolytic copper plating.
[0070]
Then, one end of each wiring 5 of the printed circuit board 10 is used as a connection terminal 6, a bump electrode 14 made of gold having a thickness of 20 μm of the semiconductor element 13 is inserted into the connection terminal 6, and the connection terminal 6 is inserted into the bump electrode 14. , So that the bump electrode 14 is depressed by 3 μm. Thereafter, the connection between each connection terminal 6 and each bump electrode 14 was confirmed, but no short circuit occurred between the adjacent bump electrodes 14.
[0071]
Comparative Example 1
Electrolytic copper plating was performed using 200 g / L CuSO ₄ ・ 5H ₂ O, 60 g / L concentrated sulfuric acid, 17 mL / L hydrochloric acid in a base solution, 100 mg / L polyethylene glycol, 5 mg / L bis-3-sulfopropyl disulphide disodium (SPS), 8 mg / L Janus A plating solution obtained by blending green B (JGB) was applied to the surface of the conductive thin film 2 between the reversal patterns of the plating resist 3 in such a manner that the plating solution was applied in parallel to 2.0 A / dm. ² Then, the printed circuit board was obtained by the same operation as in Example 1 except that the thickness was 8 μm.
[0072]
Each wiring of the conductor wiring pattern of the obtained printed circuit board had the same thickness at the center portion and both side end portions in the cross-sectional shape in the width direction.
[0073]
Then, one end of each wiring of the printed circuit board is used as a connection terminal, and a bump electrode made of gold having a thickness of 15 μm of the semiconductor element is inserted into the connection terminal so that the connection terminal is inserted into the bump electrode and the bump electrode is depressed by 3 μm. Connected to. Thereafter, the connection between each connection terminal and each bump electrode was confirmed, but a short circuit occurred between adjacent bump electrodes.
[0074]
【The invention's effect】
As described above, according to the method for manufacturing a printed circuit board of the present invention, the connection terminal is formed such that the central portion is formed thicker with respect to both end portions, so that the wired circuit board of the present invention is Since the central portion of the connection terminal is connected to the external terminal so as to sink into the external terminal, as a result, in the connection structure between the printed circuit board and the electronic component according to the present invention, the width of the external terminal in the width direction is suppressed, and The degree of swelling in the width direction can be reduced. Therefore, even if the conductor wiring pattern is formed at a fine pitch, it is possible to effectively prevent the occurrence of a short circuit between adjacent external terminals, and to improve the connection reliability between each external terminal and the connection terminal. Can be achieved.
[Brief description of the drawings]
FIG. 1 is a process chart showing one embodiment of a method for manufacturing a printed circuit board of the present invention,
(A) is a step of preparing a base insulating layer,
(B) forming a conductive thin film on the base insulating layer;
(C) forming a plating resist on the conductive thin film in a reverse pattern of the conductor wiring pattern;
(D) forming a conductive wiring pattern on the portion of the conductive thin film where the plating resist is not formed by electrolytic plating;
(E) removing the plating resist,
(F) shows a step of removing the conductive thin film corresponding to the portion where the plating resist was formed.
FIG. 2 is a plan view of a principal part showing one embodiment of the printed circuit board of the present invention.
FIG. 3 is a side sectional view showing a main part of an embodiment of the printed circuit board of the present invention.
FIG. 4 is a side sectional view showing a main part of an embodiment of the connection structure between the printed circuit board and the electronic component according to the present invention.
FIG. 5 is a process chart showing another embodiment of the method for manufacturing a printed circuit board according to the present invention,
(A) is a step of preparing a two-layer substrate,
(B) forming a blind hole in the two-layer substrate,
(C) forming a conductive thin film on the base insulating layer of the two-layer substrate,
(D) forming a plating resist on the conductive thin film in a reverse pattern of the conductor wiring pattern;
(E) forming a conductive wiring pattern on the portion of the conductive thin film where the plating resist is not formed by electrolytic plating;
(F) removing the plating resist,
(G) removing a conductive thin film corresponding to the portion where the plating resist was formed;
(H) shows a step of forming a metal layer on a conductor wiring pattern.
FIG. 6 is a schematic sectional view showing an over-etched state of a printed circuit board on which a fine-pitch conductor wiring pattern is formed by a subtractive method.
FIG. 7 is a schematic cross-sectional view showing a printed circuit board on which a fine pitch conductor wiring pattern is formed by a conventional additive method.
8 is a schematic cross-sectional view showing a state where each connection terminal of the printed circuit board of FIG. 7 is connected to each external terminal via an anisotropic conductive film or an anisotropic conductive paste.
9 is a schematic cross-sectional view showing a state where each connection terminal of the printed circuit board of FIG. 7 is connected to each external terminal via a bump electrode.
[Explanation of symbols]
1 Base insulating layer
2 Conductive thin film
3 Plating resist
4 Conductor wiring pattern
5 Wiring
6 Connection terminal
7 Central part
8 Both ends
10. Wiring circuit board
13 Semiconductor elements
14 Bump electrode

Claims (6)

A printed circuit board comprising a conductor wiring pattern,
The conductor wiring pattern is formed by plating so that a part thereof becomes a connection terminal for connecting to an external terminal,
The wiring is characterized in that the connection terminal is formed such that its thickness is thicker at the center in the width direction than at both side ends in the width direction orthogonal to the longitudinal direction of the connection terminal. Circuit board. 2. The printed circuit board according to claim 1, wherein in the connection terminal, a difference in thickness between both end portions in the width direction and a center portion in the width direction is 2 μm or more. 3. 3. The printed circuit board according to claim 1, wherein a plurality of the connection terminals are provided in the width direction, and a pitch between the connection terminals is 60 μm or less. 4. The printed circuit board according to any one of claims 1 to 3, wherein the connection terminal is formed in a cross-sectional shape in the width direction such that a center portion rises with respect to both side end portions. . A step of preparing an insulating layer,
A step of forming a plating resist on the insulating layer with a pattern inverted from the conductor wiring pattern;
A plurality of wirings are formed between the plating resists by plating so that the widthwise central portion is thicker at both ends in the width direction orthogonal to the longitudinal direction of the conductive wiring pattern. Forming a pattern, and
A method for manufacturing a printed circuit board, comprising a step of removing the plating resist. An external terminal provided on the electronic component is provided in the connection terminal of the printed circuit board according to any one of claims 1 to 4, such that the connection terminal sinks into the external terminal and swells in a width direction of the connection terminal. And a connection structure between the printed circuit board and the electronic component.

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