JP2005243899A - Printed circuit board and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printed circuit board and the manufacturing method of the same having a wiring structure which has solved a problem that danger of separating the wiring is lowered and migration is hardly generated while securing connecting property with a semiconductor element or the like upon forming a minute wiring, in the printed circuit board constituted of an insulating layer and a conductor layer which are laminated sequentially, and wiring circuits communicated with respective conductor layers through conductor passages. <P>SOLUTION: In the printed circuit board, the wiring is formed on the insulating layer on the surface of the printed circuit board, and a positional relation between one part of the wiring and the insulating layer forming an insulating substrate is under a condition that one part of bottom surface of the wiring is buried into the peripheral insulating layer and the height position of surface of the insulating layer is formed between the height position of bottom surface of the wiring and the height position of upper surface of the wiring while the height position of the section of wiring with maximal width or the sharpened and projected part such as corners or the like is not formed at the height position of the same plane as that of surface of the insulating layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a printed wiring board for various electronic devices or semiconductor devices having fine wiring, and more particularly to a flexible thin printed wiring board and a manufacturing method thereof.

  A conventional printed wiring board has a structure in which wiring is attached on an insulating substrate, and a protective resin film formed on the wiring as needed is generally used. In addition, for special applications such as sliding parts such as rotary switches and commutators, so-called flash printed wiring boards that completely embed the wiring and eliminate the step between the upper surface of the wiring and the insulating substrate are used in part. .

  FIG. 5 is a cross-sectional view showing the positional relationship between the wiring and the insulating substrate according to the prior art. In the conventional printed wiring board, the wiring (7) is formed on the surface of the insulating substrate on the surface of the substrate, and the wiring (7a) of the specified portion is submerged in the layer of the insulating substrate to the upper surface of the wiring, and the adhesive strength The wiring which strengthened is formed. In a conventional printed wiring board, a conductor layer and an insulating layer are laminated in this order, and the conductor layer forms a wiring circuit that is conducted through a conduction path, and is formed on the insulating substrate on the surface of the printed wiring board substrate. The part of the wiring for the connection terminal for input / output and the wiring of the wiring circuit are formed. The wiring (7) shown in FIG. 5 has a wiring bottom surface height position 6 formed on the substrate surface (height position 9 on the surface of the insulating layer) and wiring an insulating resin layer, such as a solder resist, for protecting the wiring. Form in other parts. One wiring (7a) does not form a solder resist layer, and the upper surface height position 5 of the wiring sinks to the surface of the insulating substrate (height position 9 on the surface of the insulating layer), thereby maintaining a strong adhesive strength. ing.

  Patent Document 1 presents a flash printed wiring board capable of having a smooth and fine circuit pattern on the surface and a manufacturing method thereof. This uses a material in which a copper foil is attached to a support substrate via a thermoplastic resin, forms a wiring pattern by etching the copper foil, and then stacks and presses with a prepreg such as glass epoxy, This is a manufacturing method belonging to a transfer method in which a flash printed wiring board having wiring embedded in a prepreg is obtained by peeling a supporting substrate and a thermoplastic resin.

  Patent Document 2 shows a manufacturing method by a transfer method characterized by embedding a wiring pattern in a thermoplastic resin. In Patent Document 3, a thick copper foil is half-etched from one side to form a convex portion corresponding to the wiring and a peripheral concave portion thereof, and after the lamination press with the convex portion corresponding to the wiring inside as in the transfer method. A printed wiring board having a step of etching while leaving an embedded wiring pattern and a manufacturing method thereof, and the wiring partially embedded in the surface of the insulating substrate exhibits a cross-sectional shape close to a hexagon from the manufacturing method, The widest part is considered to be on the surface of the insulating substrate. Patent Document 4 is a circuit board manufacturing method in which a curable composition is formed as an insulating substrate, a wiring pattern is formed on the insulating substrate, a wiring is embedded by pressing from above, and finally the insulating substrate is cured. .

The known literature is described below.
JP 2000-138444 A JP 2003-218500 A JP 2001-36200 A JP 2003-60355 A

Among the conventional techniques, in the type in which the wiring is not embedded, the miniaturization of the wiring has progressed, and there is a high risk that the wiring will be peeled off with a slight impact. Further, the miniaturization of the wiring will further progress in the future, and it is expected that the risk of the peeling of the wiring will increase at an accelerated rate. In addition, the wiring formed by etching alone has sharp corners, which further promotes the risk of peeling. At present, the peeling strength of the wiring is 9.8 to 14.7 N / cm, and it is difficult to achieve both the improvement of the peeling strength and the formation of fine wiring. That is, when the width of the wiring becomes 10 μm with the current peeling strength, the peeling occurs with a force of only 9.8 × 10 ^{−3 to} 14.7 × 10 ⁻³ N / cm. Furthermore, a flexible printed wiring board has a risk of wiring peeling due to bending, and a cover resist is indispensable. However, there are many parts that cannot be protected in particular, especially in connection parts with semiconductor elements and connection parts with other printed wiring boards, and countermeasures have been demanded. In particular, in connection by wire bonding, even if a slight misalignment occurs, the wiring easily falls and peels off.

  On the other hand, if the wiring is completely embedded, there is almost no danger of peeling of the wiring, but the bonding may be hindered by the surrounding resin in bonding with the semiconductor element, for example, as a connection terminal in many cases It is desirable that the shape protrudes from the surrounding resin. Further, the wiring partially embedded in the surface of the insulating substrate shown in Patent Document 3 is considered to have a certain effect on the improvement of peel strength and the accompanying reliability improvement by being embedded. Since it is formed by etching the front and back separately, it is difficult to accurately position the front and back, and it is extremely difficult to apply to fine wiring with a pitch of 40 μm or less required for a tape substrate. The surface of the insulating substrate that is likely to have etching residue that can become a migration progress path and the widest wiring width or the sharply protruding portion such as a corner that is the starting point of migration are located on the same plane. For this reason, as in the case of a type in which a wiring is not embedded, such as a normal printed wiring board, when a fine wiring is to be formed, there is no change to a structure in which an insulation deterioration due to migration is likely to occur. In addition, insulation reliability such as migration, which was not a problem at all with general printed wiring boards such as the printed wiring board disclosed in Patent Document 3, is formed as fine wiring with a pitch of 40 μm or less required for a tape substrate. It is very difficult to maintain with the printed wiring board, and it is known that the insulation reliability rapidly decreases especially when the gap is 15 μm or less. For this reason, since it is no longer possible to maintain insulation reliability even if it is normally etched in a conventional process and sufficiently cleaned, it is necessary to add a special process that can remove conductive materials other than copper. ing.

  An object of the present invention is to provide a wiring structure capable of solving the problems of reducing the risk of separation of a wiring even when a fine wiring is formed, making migration difficult, and ensuring connectivity with a semiconductor element or the like. It is providing the printed wiring board which has, and its manufacturing method.

The invention according to claim 1 of the present invention is a printed wiring in which an insulating layer and a conductor layer on which wiring is formed are laminated in this order, and a wiring circuit is formed in which each conductor layer is conducted through a conduction path. In the board, the wiring formed on the insulating layer on the outermost surface of the printed wiring board has a positional relationship between at least a part of the wiring and the insulating layer forming the insulating substrate, and the bottom surface of the wiring is accompanied by a peripheral insulating layer. Or the part of the bottom surface of the wiring is embedded in the surrounding insulating layer, and the height position of the insulating layer surface is the height position of the bottom surface of the wiring. The height position of the portion that is formed between the height of the upper surface of the wiring and the height of the cross section of the wiring, or the sharply protruding portion such as the corner of the wiring, is the surface of the insulating layer. The height position is not formed on the same plane. A printed wiring board, wherein the door.

  In the present invention, in the positional relationship between the wiring and the insulating layer forming the substrate, the bottom surface of the wiring is sunk or embedded, and the position of the insulating layer surface forming the substrate is between the bottom surface and the top surface of the wiring. It is a printed wiring board characterized by being located in between. In addition, in order to satisfy both the problems of reducing the risk of wiring separation and migrating migration even when fine wiring is formed, and ensuring connectivity with semiconductor elements, etc., the bottom surface of the wiring is attached to the substrate. The structure is a little embedded but not completely embedded.

  In the invention according to claim 2 of the present invention, the height position of the bottom surface of the part of the wiring is in a range of 1 to 90% of the thickness of the wiring from the height position of the surface of the insulating layer. It is formed in an embedded state in the insulating layer, and all the wirings of the same type of part have the insulating layer surface formed at the same height from the bottom of the wiring. The printed wiring board according to claim 1.

  In the present invention, in the wiring of the surface layer, the surface of the insulating layer that forms the substrate is located at a height of 1 to 90% from the bottom with respect to the copper thickness of the wiring. The type of part is a printed wiring board characterized in that the surface of the insulating layer is located at almost the same height from the bottom, and the wiring adhesion is improved by embedding the wiring even a little. The range in which the characteristics and the wiring height necessary for connection with a semiconductor element or the like are compatible is shown.

  The invention according to claim 3 of the present invention is that the part of the wiring is a part of a connection terminal with a semiconductor element or another printed wiring board, etc., and heat and / or pressure is applied in a connection operation of the connection terminal. The printed wiring board according to claim 1, wherein the printed wiring board is a wiring including a portion to which a point is added.

  In the present invention, in the printed wiring board, the wiring in which the bottom surface is embedded includes a portion to which heat and / or pressure is applied in a connection operation, such as a connection terminal with a semiconductor element or a connection terminal with another printed wiring board. Of the printed wiring board characterized by the above, a part that is particularly easily peeled off by a connection operation is shown. Specifically, the connection portion with the semiconductor element includes a wire bonding pad, a flip chip connection pad, and the like, and particularly in a COF (chip on film) connection pad and the like whose wiring width is remarkably advanced. Although it is desirable, other connection methods may be used as long as the structure has an insulating substrate under the connection pads. Similarly, any connection method may be used for terminals connected to other printed wiring boards or the like as long as an insulating substrate is provided under the connection terminals.

  In the invention according to claim 4 of the present invention, the wiring has a wiring whose side surface is formed by a gently curved surface, and the ratio of the width of the top surface of the wiring to the bottom surface of the wiring is 66.7% or more. 4. The printed wiring board according to claim 1, wherein a part of the wiring has a width of 30 μm or less. 5.

  In the present invention, the wiring side surface is formed by a gently curved surface, the ratio of the width of the upper part of the wiring to the wiring bottom surface is 66.7% or more, and at least a part of the wiring is 30 μm or less in width. This is a characteristic printed wiring board, which shows a wiring that has a gentle curved surface without unnecessary irregularities that tends to cause migration on the side surface of the wiring and is easily embedded.

In the invention according to claim 5 of the present invention, the insulating layer is one or more composite insulating layers made of different resins, and at least the resin of the insulating layer located on the surface is a thermoplastic resin or a thermosetting resin. 5. The printed wiring board according to claim 1, wherein the printed wiring board is made of resin and has flexibility.

  The invention according to claim 6 of the present invention is a printed wiring in which an insulating layer and a conductor layer on which wiring is formed are laminated in this order, and a wiring circuit is formed in which each conductor layer is conducted through a conduction path. In the board manufacturing method, a method of manufacturing a wiring formed on the insulating layer on the surface of the printed wiring board according to any one of claims 1 to 5, wherein at least a part of the wiring manufacturing method includes: After forming by etching or plating, it includes a process of temporarily softening a portion in contact with the wiring by heat and its surrounding insulating layer and applying pressure to the wiring to sink the wiring into the insulating layer. A method for manufacturing a printed wiring board.

  According to a seventh aspect of the present invention, the method for manufacturing at least a part of the wiring includes a process of forming a wiring on an insulating layer of another substrate by a transfer method after the wiring is formed by etching or plating. The printed wiring board manufacturing method according to claim 6, wherein the printed wiring board is a manufacturing method.

  In the present invention, after the wiring is formed by etching or plating, the process includes a process of temporarily softening the insulating layer located in a portion in contact with the wiring by heat and applying pressure to the wiring to sink the wiring into the insulating layer. Is a method for producing a printed wiring board. Another manufacturing method is a method for manufacturing a printed wiring board, which includes a process of forming a wiring on another substrate by a transfer method after the wiring is formed by etching or plating.

  According to the present invention, the above-described problems in the prior art are solved, and other new effects are produced. First of all, it was possible to achieve both the miniaturization of the wiring and the improvement of the peel strength, which had been a problem with the conventional technology in which the wiring was not embedded, and it was possible to sufficiently cope with the future miniaturization of the wiring. .

  In addition, the connection reliability with the connection part with the semiconductor element and the connection part with other printed wiring boards is improved, and the connection reliability is improved, and the unevenness of the wiring directly under the part where the semiconductor element is mounted is reduced. As a result, the reliability of mounting semiconductor elements has been improved. In particular, remarkable effects were seen in improving the embedding property between the wirings in the ACF (Anisotropic Conductive Film) connection with the semiconductor element, achieving further miniaturization of the COF connection pad, preventing peeling, and improving the stability of the die bonding.

  Apart from this, the apparent thickness of the wiring has been reduced, preventing the occurrence of air bubbles (voids) and underfilling (scratching) that were likely to occur in the recesses between the wires when overcoating is applied to the wires. It was also possible to reduce the thickness of the overcoat.

  In addition, the insulation is less likely to deteriorate due to migration, and the insulation reliability of the COF substrate, which requires a wiring interval of 20 μm or less, particularly 15 μm or less, is greatly improved.

  This is because the degradation of insulation due to migration in the prior art is because the wiring corners, especially the corners of the bottom surface, where the cross-sectional shape is acute, are likely to leave a minute residue due to etching, and the spacing between adjacent wirings. It was a particularly prone part because it was most close. For this reason, by separating the surface of the insulating layer between the wirings, the migration source and the traveling path are separated, and the insulation reliability of the wirings having a gap of 20 μm or less, particularly 15 μm or less, is greatly improved. it is conceivable that.

  On the other hand, it has become difficult to inhibit the junction with the semiconductor element, which has been a problem when the wiring is completely embedded, and the occurrence of problems during assembly has been almost eliminated.

  FIG. 1A and FIG. 1B are cross-sectional views showing the positional relationship between the wiring and the insulating substrate according to the present invention. In the printed wiring board of the present invention shown in FIG. 1A, the wiring (7) is formed on the surface of the insulating substrate on the surface of the substrate, and the wiring (7a) at the specified portion sinks into the layer of the insulating substrate, Wiring with enhanced adhesion is formed. In the printed wiring board, a conductor layer and an insulating layer are laminated in this order, the conductor layer forms a wiring circuit that is conducted through a conduction path, and on the insulating substrate on the surface of the substrate of the printed wiring board, Wiring portions for connection terminals for input / output and wiring for wiring circuits are formed. In the wiring (7) shown in FIG. 1A, an insulating resin layer, for example, a solder resist, which is formed on the substrate surface and protects the wiring is formed. In one wiring (7a), a solder resist or the like is not formed, and the bottom surface of the wiring sinks into the layer of the insulating substrate, maintains a strong adhesive strength, and has the same height to the top surface of the wiring (7a). The height is adjusted. In the printed wiring board of the present invention shown in FIG. 1B, the wiring (7) is formed on the surface of the insulating substrate on the surface of the substrate, and the wiring (7a) at the specified portion sinks with the surrounding insulating substrate surface. In other words, a wiring with enhanced adhesion is formed. In the wiring (7) shown in FIG. 1B, an insulating resin layer, for example, a solder resist, which is formed on the substrate surface and protects the wiring is formed. In one wiring (7a), a solder resist or the like is not formed, and the bottom surface of the wiring sinks with the surface of the surrounding insulating substrate, maintains a strong adhesive strength, and has a height up to the top surface of the wiring (7a). Are adjusted to be the same height. The wiring (7a) is the wiring of the specified part, and the positions thereof are discretely arranged, and only the wiring part at the position is insulated from the bottom of the wiring by using a laminating press method by heating and pressing. Sink below the surface of the substrate.

  Examples will be described below.

  FIG. 2 is a cross-sectional view showing a state in the main process of the first embodiment of the present invention. Adhesive (19) (type X (trade name), Yodogawa Paper Co., Ltd.) having a thickness of 12 μm on one side of a polyimide film (12) having a thickness of 50 μm (Upilex S (trade name): Ube Industries, Ltd.) The laminated insulating substrate was punched with a mold to form a sprocket hole (see FIG. 2a). A copper foil (11) having a thickness of 18 μm was laminated on the adhesive side at a laminator setting temperature of 120 ° C., a laminating roller pressure of 0.2 MPa, and a laminating speed of 1.2 m / min (see FIG. 2 b). Usually, the adhesive is cured by heating after laminating, but this is omitted in this example, and after cleaning the copper foil surface, a dry film resist having a thickness of 10 μm (14) (SUNFORT SPG-102 (trade name): Asahi Kasei Co., Ltd.) was laminated at a roll temperature of 105 ° C., a pressure of 0.3 MPa, and a laminating speed of 1.5 m / min (see FIG. 2c). After exposing the wiring pattern with a projection type exposure apparatus, spraying a 30% 1% sodium carbonate solution with a spray for about 30 seconds, developing, then spraying a ferric chloride solution heated to 50 ° C with a spray, etching the exposed copper Then, a dry film resist pattern (15) was peeled off by spraying a 3% sodium hydroxide solution at 50 ° C. by spraying (see FIGS. 2d to 2f). A desired copper wiring pattern was formed on the polyimide film by the above process. In this state, a copper wiring pattern having a thickness of about 18 μm is formed on the adhesive forming the insulating substrate.

  Next, the adhesive is softened by heating while suppressing generation of bubbles from the adhesive at 140 ° C. and a pressure of about 1 MPa finally by heating and pressurizing step by step with a laminating press for a rigid substrate, The copper wiring (17a) was submerged by about 10 μm in the adhesive (29) softened by pressure, and the adhesive was cured (see FIG. 2g).

Furthermore, after putting the adhesive in an oven at 140 ° C. for 5 hours to completely cure the adhesive, a solder resist is printed, and electrolytic gold plating is applied, and the pad width is 80 to 85 μm, the pad gap is 15 to 20 μm, and the pitch is 100 μm. A semiconductor device mounting tape substrate including a wire bonding pad was completed (not shown).

  FIG. 3 is a cross-sectional view illustrating a state in the main process of the second embodiment of the present invention. A substrate obtained by laminating a 12 μm thick copper foil (21) on one side of a polyether ether ketone thermoplastic resin film (22) (manufactured by Mitsubishi Plastics Co., Ltd.) having a thickness of 50 μm was punched with a die to form a sprocket hole. . After cleaning the copper foil surface, a positive liquid resist (24) (PMER-P (trade name): manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied and dried under conditions such that the thickness after drying was 2 to 3 μm. (See FIG. 3b). After exposing the wiring pattern with a projection type exposure apparatus and immersing it in a special developer at 25 ° C., the exposed copper is etched by spraying a ferric chloride solution heated to 50 ° C. with a spray. A resist pattern (25) was peeled off by spraying a 3% sodium hydroxide solution (see FIGS. 3c to 3e).

  The pattern of the desired copper wiring (27) was formed on the thermoplastic film by the above process. In this state, a copper wiring pattern having a thickness of about 12 μm is formed on the thermoplastic resin constituting the insulating substrate, and the bottom surface of the formed wiring pattern has a shape close to a trapezoid whose maximum width is 10 μm. A wiring pattern having a bottom width of 14 μm and a gap of 16 μm was obtained. Further, the ratio of the width of the upper portion of the wiring with respect to the bottom surface of the wiring at this time was calculated to be 71.4%. When this ratio is 60% or less, the wiring has a cross-sectional shape with a so-called hem, and when the wiring is pushed in by a press, the hem portion is deformed without being pushed and is bent. Therefore, a shape with less tailing of 60% or more, preferably 66.7% or more is desirable at best, and the larger the numerical value, the better the embedding property. Further, the side surface of the wiring had a gentle shape with no irregularities.

Next, the thermoplastic resin film (22) is softened under the conditions of a maximum temperature of 240 ° C. and a maximum pressure of 1 MPa by stepwise heating and pressurizing with a laminating press for a rigid substrate, and copper wiring (27a ) Was submerged by about 4 to 8 μm (see FIG. 3 f). It is desirable to confirm the amount of subsidence in advance by adjusting the conditions and adjust it so that the amount of subsidence is appropriate, and it is necessary to set an optimal value depending on the type of connection pad or the like. COF (Chip On
In the case of a film) connection pad, the height slightly below 10 μm and its front and back were optimal when comprehensively judged including the processability of the wiring. By printing a solder resist on the surface and performing tin plating, a semiconductor element mounting tape substrate including a COF connection pad with a pitch of 30 μm was completed (not shown).

  FIG. 4 is a cross-sectional view showing a state in the main process of the third embodiment of the present invention. Cleaning the surface of the composite substrate in which a copper foil (31) having a thickness of 18 μm is attached to one side of an epoxy resin film (32) having a thickness of about 10 μm and a copper foil (33) having a thickness of 35 μm is attached to the opposite side. Then, a positive type liquid resist (34) (PMER-P (trade name): manufactured by Tokyo Ohka Kogyo Co., Ltd.) was applied and dried on an 18 μm copper foil under conditions such that the thickness after drying was 2 to 3 μm. (See FIGS. 4a-b). The wiring pattern was exposed with a projection type exposure apparatus, developed by immersion in a dedicated developer at 25 ° C., and then a protective PET film (36) was bonded onto the back 35 μm copper foil (see FIGS. 4c to d). ). After etching the exposed copper by spraying a ferric chloride solution heated to 50 ° C. by spraying, and spraying a 3% sodium hydroxide solution at 50 ° C. by spraying to remove the resist pattern (35), the PET film on the back side (36) was peeled off (see FIG. 4e).

Through the above process, a desired copper wiring pattern having a thickness of about 18 μm was formed on the epoxy resin side of the composite substrate composed of a copper foil having a thickness of 35 μm and an epoxy resin layer having a thickness of 10 μm. At this time, when the formed wiring pattern was examined, it was a shape close to a trapezoid whose bottom surface had the maximum width, and the wiring pattern had a width of 20 μm at the top of the wiring, a width of 24 μm at the bottom and a gap of 26 μm. Further, the ratio of the width of the upper portion of the wiring to the bottom surface of the wiring was 83.3%.

  Next, a polyimide film (38) having a thickness of 50 μm (Upilex S (trade name): manufactured by Ube Industries, Ltd.) and a film-like insulating sheet (39) for build-up printed wiring boards (ABF-45H (trade name)) : Ajinomoto Fine-Techno Co., Ltd.) and a composite substrate with a pattern formed so that the surface of the wiring (37) is on the inside (see FIG. 4f) and pasted at a roll laminator temperature of 140 ° C. and a pressure of about 0.5 MPa Combined. The film-like insulating sheet (39) was softened by heating at the time of bonding, and the copper wiring (37a) was completely embedded (see FIG. 4g). Then, it heated for 30 minutes in 150 degreeC oven, and the film-like insulating sheet was hardened.

  A 35 μm copper foil (33) exposed on the surface was removed by spraying a ferric chloride solution heated to 50 ° C. by spraying (see FIG. 4h), and the thickness of 10 μm constituting the composite substrate by the permanganate treatment The epoxy resin film (32) was completely removed (see FIG. 4i). At this time, the cured film-like insulating sheet between the wiring patterns was simultaneously removed at a depth of 2 to 5 μm from the surface. Finally, a solder resist was printed and electrolytic gold plating was performed to complete a semiconductor element mounting tape substrate including a wire bonding pad with a pitch of 100 μm (not shown).

(A)-(b) is sectional drawing which shows the positional relationship of the wiring by this invention, and an insulated substrate. It is sectional drawing which shows the state in the main processes of Example 1 of this invention. It is sectional drawing which shows the state in the main processes of Example 2 of this invention. It is sectional drawing which shows the state in the main processes of Example 3 of this invention. It is sectional drawing which shows the positional relationship of the wiring and insulating board by a prior art.

Explanation of symbols

2 ... Insulating substrate 5 ... Height position 6 on the upper surface of the wiring 7 ... Height position on the bottom surface of the wiring 7 ... Wiring 7a ... Wiring (embedded state)
9 ... Height position of insulating layer surface 11 ... Copper foil 12 ... Polyimide film (insulating substrate)
14 ... Dried film resist 15 ... Dried film resist pattern 17 ... Wiring 17a ... Wiring (embedded state)
21 ... copper foil 22 ... thermoplastic resin film (insulating substrate)
24 ... Positive type liquid resist 25 ... Resist pattern 27 ... Wiring 27a ... Wiring (embedded state)
31: 18 μm copper foil 32: Epoxy resin film (insulating substrate)
31 ... 35 μm copper foil 34 ... positive liquid resist 35 ... resist pattern 36 ... PET film 37 ... wiring 37a ... wiring (embedded state)
38 ... 50μm polyimide film (insulating substrate)
39 ... Film-like insulating sheet (insulating substrate)

Claims (7)

  In a printed wiring board in which an insulating layer and a conductor layer on which a wiring is formed are laminated in this order, and a wiring circuit that is conducted to each conductor layer through a conduction path is formed, insulation on the outermost surface of the printed wiring board For the wiring formed on the layer, the positional relationship between at least a part of the wiring and the insulating layer forming the insulating substrate is such that the bottom surface of the wiring sinks with the surrounding insulating layer, or A part of the bottom of the wiring is embedded to the inside of the surrounding insulating layer, and the height of the insulating layer surface is between the height of the bottom of the wiring and the height of the top of the wiring. The height position of the portion where the width of the cross section of the wiring is the maximum, or the sharply protruding portion such as the corner portion of the wiring is the same plane height as the height position of the insulating layer surface. Printed wiring board characterized in that it is not formed in the vertical position   The height position of the bottom surface of the part of the wiring is formed in a state of being embedded in the insulating layer to a depth of 1 to 90% of the thickness of the wiring from the height position of the surface of the insulating layer. 2. The printed wiring board according to claim 1, wherein all of the wirings of the same type of part have an insulating layer surface formed at a position where the height from the bottom surface of the wiring is the same.   The part of the wiring is a part of a connection terminal with a semiconductor element, another printed wiring board, or the like, and includes a part to which heat and / or pressure is applied in a connection operation of the connection terminal. The printed wiring board according to claim 1 or 2.   The wiring is formed by a curved surface having a gentle wiring side surface, the wiring has a wiring whose ratio of the width of the top surface of the wiring to the bottom surface of the wiring is 66.7% or more, and at least a part of the wiring has a width of 30 μm or less. The printed wiring board according to claim 1, wherein:   The insulating layer is a composite insulating layer of one layer or two or more layers made of different resins, and at least the resin of the insulating layer located on the surface is made of a thermoplastic resin or a thermosetting resin and has flexibility. The printed wiring board according to claim 1, wherein the printed wiring board is a printed wiring board.   6. A printed wiring board manufacturing method in which an insulating layer and a conductor layer on which wiring is formed are laminated in this order, and a wiring circuit is formed in which each conductor layer is conducted through a conduction path. A method of manufacturing a wiring formed on an insulating layer on a surface of a printed wiring board according to any one of the above, wherein at least a part of the wiring is manufactured by etching or plating and then wiring by heat A method of manufacturing a printed wiring board, comprising: a step of temporarily softening a portion in contact with the insulating layer and a surrounding insulating layer and applying pressure to the wiring to sink the wiring into the insulating layer.   7. The printed wiring board according to claim 6, wherein the manufacturing method of at least a part of the wiring includes a process of forming a wiring on an insulating layer of another substrate by a transfer method after the wiring is formed by etching or plating. Manufacturing method.

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