JP2003209342A - Circuit board and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow a shape fault of a wiring when a wiring pitch is miniaturized to be reduced in a method for manufacturing a circuit board. <P>SOLUTION: The method for manufacturing the circuit board having the wiring formed on one surface of an insulation board comprises the step of forming a conductive thin film on the surface of a temporary board, forming a resist (plating resist) on the conductive thin film, forming the wiring of a predetermined pattern by electric copper plating, adhering the insulation board to the surface of he temporary board on which the wiring is formed, releasing the temporary board, and transferring the wiring, the resist and the conductive thin film to the insulation board, and removing the conductive thin film. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a wiring board and a wiring board, and more particularly to a method of manufacturing a single-sided wiring board for forming fine wiring used in a COF (Chip On Film) type semiconductor device or the like. It relates to technology that is effective when applied.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a wiring board, a method of forming a wiring having a predetermined pattern on a surface of an insulating substrate is a subtractive process, a full additive process, and a semi-additive process. There is an additive method (semi-additive process).

Of the wiring boards, for example, BGA
(Ball Grid Array), CSP (Chip Size Package), and other interposers used in semiconductor devices, in other words, wiring boards that match the external electrodes of the semiconductor chip with the terminals on the motherboard or perform grid conversion. Since the external terminals (bonding pads) are densified due to the trend toward higher performance and higher functionality, correspondingly, wiring with a fine pitch and high density is required.

Particularly, in a wiring board used for a COF type semiconductor device such as a driver IC of a liquid crystal display,
In the wiring 11 provided on the surface of the insulating substrate 1 as shown in FIG. 11, the distance (conductor pitch) CP between the center lines of the adjacent wirings 11 is required to be about 20 μm to 30 μm. It is becoming.

In order to miniaturize and increase the density of the conductor pitch CP, the width (conductor width) C of the wiring 11 as shown in FIG. 11 is used.
It is necessary to reduce W and the distance (conductor gap) CS between the end portions 11A of the adjacent wirings 11, and various improvements have been added to the respective wiring forming methods.

The subtractive method is shown in FIG.
As shown in, using a copper clad plate in which a copper foil (conductive thin film) 12 such as an electrolytic copper foil or a rolled copper foil is formed on the surface of an insulating substrate 1 such as a polyimide tape or a glass cloth-based epoxy resin substrate, As shown in FIG. 12B, after forming a resist (etching resist) 13 corresponding to the wiring pattern to be formed on the surface of the copper foil 12, as shown in FIG. Is a method of forming the wiring 11 by removing unnecessary portions of the wiring by etching.

In the subtractive method, the copper foil 1 is used.
When etching 2, the side surfaces of the wiring 11 are also etched. At this time, the etching amount of the side surface portion of the wiring 11 varies depending on the density of the wiring 11 to be formed. As shown in FIG.
1 end portion 11A has poor linearity, and a predetermined conductor width CW
It is easier to get thicker or thinner than that. Further, if the copper foil 12 has a lattice defect or the like, the etching rate locally increases or decreases.
It is easy to form a defective NC or protrusion. Therefore, the shapes of the wirings 11 become uneven, and the electrical characteristics are likely to change.

Further, when the thickness (conductor thickness) CT of the wiring 11 as shown in FIG. 11 is large and the conductor gap CS is narrow, as shown in FIG. 13 (b), the copper foil 12 is formed. The etching residue 12A is likely to occur.

From the above, it is difficult to apply the subtractive method to, for example, a method of manufacturing a wiring board having a conductor pitch CP of 40 μm or less.

The full additive method is a method of directly forming the wiring 11 on the insulating substrate 1 only by electroless plating, and as shown in FIG. The agent 14 is provided, and a catalyst 15 such as palladium (Pd) is provided on the adhesive 14. Thereafter, as shown in FIG. 14B, a resist (plating resist) 4 having an opening in the wiring pattern portion to be formed is formed on the adhesive 14, and the wiring 11 is formed by the electroless copper plating film 16. At this time, the plating resist 4 is generally used as it is as a solder protective film (permanent mask).

In the full-additive method, when the plating resist 4 is used as it is as a permanent mask, the catalyst 15 remains between the plating resist 4 and the insulating substrate 1 (adhesive 14). Therefore, as shown in FIG. 15, electromigration 16 ′ is likely to occur through the catalyst 15 under the plating resist 4, so that when the distance between the adjacent wirings 11 is narrowed, the adjacent wirings 11 are likely to be short-circuited. . Here, FIG. 15 is a sectional view corresponding to FIG. 14B, but hatching of the plating resist 4 is omitted for the sake of clarity.

Therefore, it is difficult to apply the full additive method to, for example, a method of manufacturing a wiring board having a conductor pitch CP of 40 μm or less.

Further, in the full additive method, since the wiring 11 is formed by electroless plating, it is possible to prevent the conductor from becoming thick or thin, as well as the protrusion or the defect as in the subtractive method. Since the process for forming the copper plating film 16 is complicated and time-consuming,
Manufacturing costs are likely to rise.

On the other hand, the semi-additive method is shown in FIG.
As shown in (a), a thickness of 3 μm is formed on the surface of the insulating substrate 1 by, for example, electroless plating or sputtering.
After forming a thin conductive thin film 7 having a thickness of about m, FIG.
As shown in FIG. 5, a resist (plating resist) 4 is formed on the conductive thin film 7 so that the wiring pattern portion to be formed is opened, and the conductive thin film 7 is used as an electrode (base), for example, electrolytic copper plating. The film 17 is formed. afterwards,
The plating resist 4 is removed, and as shown in FIG. 16C, the exposed portion of the conductive thin film 7 is removed by an etching process, and the wiring 11 composed of the conductive thin film 7 and the electrolytic copper plating film 17 is removed. Is a method of forming.

In the case of the semi-additive method, the thickness of the conductive thin film 7 is sufficiently smaller than the thickness of the electrolytic copper plating film 17 and etching can be performed in a short time. It is possible to prevent the conductor from becoming thicker or thinner, and from protruding or missing. In addition, since the conductive thin film 7 is thin and can be easily removed by etching, the adjacent wirings 11 can be reliably separated, and short-circuiting between the adjacent wirings 11 due to the etching failure is unlikely to occur.

At this time, even if the conductive thin film 7 is formed by electroless plating, the unnecessary catalyst can be removed by washing after the unnecessary conductive thin film 7 is removed. However, a short circuit between the adjacent wirings 11 due to electromigration hardly occurs. Further, when the conductive thin film 7 is formed by sputtering, a catalyst is not required, and therefore short circuit between adjacent wirings due to electromigration does not occur.

Therefore, the semi-additive method is easier to apply to a method of manufacturing a wiring board having a conductor pitch CP of 40 μm or less than the subtractive method and the full-additive method.

In addition, in recent years, in addition to the wiring formation by the subtractive method, the full additive method, and the semi-additive method, for example, a wiring pattern is formed on a metal plate such as a stainless plate by electrolytic copper plating,
A method has been proposed in which an insulating substrate is bonded onto the wiring pattern, the metal plate is peeled off, and the wiring pattern is transferred onto the insulating substrate (transfer method).

In the case of the transfer method, since wiring can be formed directly on the metal plate, unnecessary conductors are removed by etching treatment such as the subtractive method or the semi-additive method, or the full-additive method is used. No catalyst like the method is required. Therefore, for example, it is easy to apply to a method for manufacturing a wiring board having a conductor pitch CP of 40 μm or less.

[0020]

However, among the above-mentioned conventional techniques, when the wiring 11 is formed by the semi-additive method, the conductive thin film 7 serving as the base has a thickness smaller than that of the copper electroplating film 17. Is thin enough that
Quick etching is performed using the electrolytic copper plating film 17 as a mask. At this time, the surface of the electrolytic copper plating film 17 is slightly etched, and as shown in FIG.
There is a problem that the flatness of the surface of the wiring 11, that is, the surface 17A of the copper electroplating film 17 is deteriorated. In addition, there is a problem in that the etching amount of the surface 17A of the electrolytic copper plating film varies, and the thickness of the wiring 11 tends to vary.

If the flatness of the surface 17A of the copper electroplating film is deteriorated or the thickness of the wiring 11 is varied, the stability of the semiconductor chip when mounting the semiconductor chip is deteriorated and the connection is improved. There was a problem that reliability was lowered.

Although not so much as the case where the wiring is formed by the subtractive method, the side surface of the wiring (electrolytic copper plating film 17) is also etched, so that the wiring 11 may be thinned or chipped. There was a problem.

In recent years, in order to prevent the surface 17A of the copper electroplating film from being easily etched during the quick etching, the conductive thin film 7 is made of, for example,
There is a method of using a conductor such as a nickel-copper alloy or a nickel-chromium alloy that has a faster etching rate than copper or a conductor that dissolves in a solution in which copper is less soluble. In that case, the conductive thin film 7 is selectively etched. As shown in FIG. 17B, an undercut 7A easily occurs in the conductive thin film 7.

When the undercut 7A is formed in the conductive thin film 7, the contact surface between the wiring 11 (electrolytic copper plating film 17) and the insulating substrate 1 becomes narrow, and the adhesion is reduced. However, there is a problem in that the peel strength of the wiring is reduced and the wiring 11 is easily peeled off. Therefore, as the width CW of the wiring 11 is reduced, it becomes difficult to secure the adhesion reliability between the wiring 11 and the insulating substrate 1. Therefore, when the conductor pitch CP is further miniaturized, the semi-additive There was a problem that it became difficult to apply the law.

Further, in the case of the wiring board manufacturing method to which the transfer method is applied, a material having a low adhesion to the wiring is used as the metal plate, and a force such as bending from the outside is applied to the metal plate. When added, the wiring is easily peeled off. Also,
When the width (conductor width) CW of the wiring becomes narrower, the adhesive force between the wiring and the metal plate becomes smaller, and the wiring easily peels off. Therefore, TCP (Tape Carrier Pack
When forming a wiring board by the reel to reel method used in manufacturing methods such as age,
There is a problem that it is difficult to apply the transfer method.

Further, in the case of the transfer method, since it is difficult to apply the reel-to-reel method, it is difficult to mass-produce wiring boards having the same pattern at one time, and it is difficult to reduce the manufacturing cost of the wiring boards. there were.

It is an object of the present invention to provide a technique capable of reducing the shape defect of the wiring when the wiring pitch is miniaturized in the method of manufacturing the wiring board.

Another object of the present invention is to provide a technique capable of improving the bonding reliability of the wiring when the wiring pitch is made fine in the method of manufacturing the wiring board.

Another object of the present invention is to provide a technique capable of mass-producing a wiring board having a fine wiring pitch at one time.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0031]

The outline of the invention disclosed in the present application is as follows.

(1) In a method of manufacturing a wiring board in which wiring is formed on one surface of an insulating substrate, a step of forming a conductive thin film on the surface of a temporary substrate and a resist (plating resist) formed on the conductive thin film Then, a step of forming a wiring of a predetermined pattern by electrolytic copper plating, a step of adhering an insulating substrate with an adhesive to the surface of the temporary substrate on which the wiring is formed, and peeling off the temporary substrate. A method of manufacturing a wiring board, comprising: a step of transferring the wiring, the resist, and the conductive thin film to the insulating substrate; and a step of removing the conductive thin film.

According to the above-mentioned means (1), after the wiring is formed on the temporary substrate by using the semi-additive method, the wiring is transferred to form the surface of the conductive thin film to be removed by etching or the like. Exposed to. Therefore, the conductive thin film can be easily removed.

When the conductive thin film is removed by etching, for example, the plating resist is in close contact with the side surface of the wiring, and the side surface of the wiring and the adhesive interface with the insulating substrate are not etched. for that reason,
Even when the width of the wiring is narrowed, it is possible to prevent variations in the shape of the wiring and a reduction in the adhesive force between the wiring and the insulating substrate.

Further, by exposing the conductive thin film to the surface as in the case of the above (1), the limit of miniaturization of the wiring pitch depends only on the precision when the plating resist is formed. Therefore, for example, the wiring pitch is 4
This facilitates application to a method for manufacturing a wiring board having a thickness of 0 μm or less.

Further, in the above-mentioned means (1), the insulating substrate is adhered using an adhesive, and the adhesive force or the adhesive force between the temporary substrate and the conductive thin film is increased before the step of peeling the temporary substrate. A step of adhering the insulating substrate after forming the wiring on the temporary substrate by performing a heat treatment so that the adhesive force between the insulating substrate and the wiring and the resist (plating resist) is lower than that of the insulating substrate. It is possible to prevent the wiring from being peeled off during the transportation to, and to easily peel the temporary substrate after the insulating substrate is bonded.

At this time, in the step of adhering the insulating substrate, a thermosetting resin is used as the adhesive, and the provisional substrate and the conductive thin film are brought into close contact with each other by heating when curing the thermosetting resin. It is preferred to reduce the force or adhesion. In this case, the step of peeling the temporary substrate can be performed immediately after the step of adhering the insulating substrate, and it is not necessary to separately provide the step of peeling the temporary substrate.

The adhesive is not limited to the thermosetting resin, but may be a thermoplastic resin, for example.
Also in this case, when the insulating substrate is bonded, since the insulating substrate and the temporary substrate are heated to soften the thermoplastic resin, the adhesion force or the adhesion between the temporary substrate and the conductive thin film by heating. If the force is reduced, the step of peeling the temporary substrate can be performed immediately after the step of adhering the insulating substrate, and there is no need to separately provide the step of peeling the temporary substrate.

Further, an insulating substrate is used as the temporary substrate, and the insulating substrate is bonded by using a thermosetting resin or a thermoplastic resin, and the temporary substrate and the conductive thin film are heated by heating at the time of bonding. By reducing the adhesive force or the adhesive force, the wiring is not easily peeled off even when bending deformation is applied to the temporary substrate before the step of adhering the insulating substrate. Therefore, the reel-to-reel method applied to the conventional TCP manufacturing method, that is, a tape-shaped insulating substrate that is long in one direction is used as the temporary substrate, and each of the steps is wound on a reel. Since it can be performed while winding the tape-shaped insulating substrate on another reel, a large number of wiring substrates having the same pattern can be produced at once.

In the step of adhering the insulating substrate,
As the adhesive, the thermosetting resin or the thermoplastic resin is used, and in addition to reducing the adhesion between the temporary substrate and the conductive thin film when performing heat treatment, for example, the wiring and the insulation The adhesive strength between the substrate and the adhesive strength between the plating resist and the insulating substrate is higher than the adhesive strength between the temporary substrate and the conductive thin film or the adhesive strength. Good. In that case, the wiring can be transferred without performing the heat treatment.

(2) A wiring board in which wiring is provided on one surface of an insulating substrate via an adhesive and a plating resist is provided between the wirings, wherein the wiring and the plating resist are the insulating material. This is a wiring board in which what is provided on a conductive thin film provided on the surface of a temporary substrate prepared separately from the substrate is transferred to one surface of the insulating substrate via an adhesive.

According to the means (2), by transferring the wiring and the plating resist provided on the temporary substrate, there are few variations in wiring shape and shape defects, and reliability of electrical characteristics is high. A wiring board can be obtained.
Further, since there are few variations in the wiring shape and shape defects, miniaturization of the wiring is facilitated, and a small-sized and high-density wiring board can be obtained. Therefore, it is easy to reduce the size and increase the functionality of the semiconductor device using the wiring board.

Hereinafter, the present invention will be described in detail with reference to the drawings together with the embodiments (examples).

In all the drawings for explaining the embodiments, parts having the same function are designated by the same reference numerals, and the repeated description thereof will be omitted.

[0045]

BEST MODE FOR CARRYING OUT THE INVENTION Before describing the embodiments of the present invention, first, an example of a wiring board according to the present invention will be described.

FIG. 1 and FIG. 2 are schematic diagrams showing a schematic structure of an example of a wiring board according to the present invention. FIG. 1 is a plan view of the wiring board, and FIG. 2 is A- of the wiring board shown in FIG. It is sectional drawing in the A'line.

1 and 2, 1 is an insulating substrate, 1
A is an opening (perforation hole), 2 is an adhesive, 3
Is wiring (electrolytic copper plating film), 4 is plating resist (solder protective film), and 5 is terminal plating.

The main wiring board according to the present invention is
For example, wiring boards (interposers) used in COF semiconductor devices such as driver ICs for liquid crystal displays
Is a single-sided wiring board in which wiring (conductor pattern) is provided only on one side of the insulating board. As shown in FIGS. 1 and 2, a predetermined shape is provided on the surface of the film-like insulating board 1 with an adhesive 2 interposed therebetween. The wiring 3 of the pattern is provided.

Further, as shown in FIG. 2, the wirings 3 are insulated from each other by a plating resist (solder protective film) 4, and the surface of each wiring 3 is provided with a terminal plating 5. . For the terminal plating 5, for example, a gold plating film with a nickel plating film as a base, a tin plating film, or the like is used.

The insulating substrate 1 is, for example, a tape material which is elongated in one direction, such as a polyimide tape,
Positioning openings (perforation holes) 1A are provided along the longitudinal ends.

When a semiconductor device is formed using the wiring board, the chip mounting area L on the wiring board is formed.
A semiconductor chip is mounted on each of the wirings 1 and the connection portion between the wiring 3 and the external terminal (bonding pad) of the semiconductor chip is sealed with a sealing resin, and then the individualized region L2 is cut.

Semiconductor devices using the wiring board have been made smaller and more dense, and the pitch of the wirings 3 (conductor pitch) as shown in FIG. 11 has been about 20 μm to 30 μm. is there. Therefore, it is necessary to reduce the width of the wiring 3 (conductor width) and the distance between the end portions of adjacent wirings (conductor gap) while preventing deterioration of electrical reliability.

An embodiment of a method of manufacturing a wiring board, which prevents the reduction of the electrical reliability when the conductor width and the conductor gap are narrowed and enables the miniaturization of the wiring pattern, will be described below.

(Embodiment) FIGS. 3 to 6 are schematic views for explaining a method for manufacturing a wiring board according to an embodiment of the present invention. FIGS. 3 (a), 3 (b) and 3 (C) and FIG. 3 (d) are cross-sectional views of the step of forming wiring on the temporary substrate, and FIGS. 4 (a), 4 (b), and 5 show the step of transferring the wiring to the insulating substrate. Sectional drawing, FIG. 6 is sectional drawing of the process of removing a conductive thin film.

3 to 6, 6 is a temporary substrate, 7 is a conductive thin film, 8 is a heating furnace, and 9 is a peeling roller.

The method of manufacturing the wiring board of this embodiment will be described below with reference to FIGS.

First, as shown in FIG. 3A, a conductive thin film 7 is formed on an insulating temporary substrate 6. For example, a polyimide tape is used for the temporary substrate 6, and as the conductive thin film 7, a vapor deposition film of copper, nickel-copper alloy, nickel-chromium alloy, or the like is formed on the surface of the temporary substrate 6 by sputtering or the like. . At this time, the adhesive strength (adhesion) between the temporary substrate 6 and the conductive thin film 7 depends on the combination of the temporary substrate 6 and the conductive thin film 7, but is about 100 gf.
/ cm to 500 gf / cm.

At this time, as the temporary substrate 6, for example, a substrate which is long in one direction, such as used for manufacturing TCP, is used, and the steps of forming the conductive thin film 7 and the following steps are performed. Reel-to-reel method, that is,
It is assumed that the temporary substrate 6 wound on a reel is wound on another reel.

Next, as shown in FIG. 3B, after a resist (plating resist) 4 is formed on the surface of the conductive thin film 7 where the wiring 3 is not formed, the conductive thin film 7 is removed. The wiring (electrolytic copper plating film) 3 is formed by electrolytic copper plating as a cathode, as shown in FIG.

When a fine wiring pattern is formed as in the wiring board of this embodiment, the plating resist 4 is generally formed by a photographic method using a photosensitive resist. Therefore, the width (conductor width) CW and the interval (conductor gap) CS of the wiring 3 are determined by the exposure accuracy when the plating resist 4 is formed. At this time, when a positive type resist such as polymethylmethacrylate (PMMA) is used as the plating resist 4, the exposure limit that can ensure the accuracy of the pattern to be formed is about 5 μm, so the width CW of the wiring 3 It is possible to narrow the distance CS and the distance CS to about 5 μm.

Even when a negative type dry film is used as the plating resist 4, since the exposure limit for ensuring the accuracy of the pattern to be formed is about 15 μm, the width CW of the wiring 3 and the spacing CS of the wiring 3 Respectively
It can be narrowed to about 15 μm.

When the wiring 3 is formed by the electrolytic copper plating, the wiring 3 can be formed in a shorter time than the full additive method in which the wiring is formed by electroless copper plating.

At this time, the growth surface 3A of the wiring 3
May have a convex shape as shown in FIG. 3C or may have a concave shape (not shown) depending on the composition of the additive contained in the plating bath used. Therefore, if necessary, as shown in FIG. 3D, the growth surface 3A of the wiring 3 is polished to planarize the surface.

Next, as shown in FIG. 4A, the insulating substrate 1 is adhered to the surface on which the wiring 3 and the plating resist 4 are formed by using the adhesive 2, and then, as shown in FIG. As shown in FIG. 5, the temporary substrate 6 is peeled off from the conductive thin film 7, and the wiring 3, the plating resist 4, and the conductive thin film 7 are transferred to the insulating substrate 1.

At this time, as the adhesive 2, for example,
When a thermosetting resin such as an epoxy resin or a polyimide resin is used, the adhesive force between the temporary substrate 6 and the conductive thin film 7 decreases in the heat treatment for curing the adhesive 2, It will be about 50gf / cm to 200gf / cm. On the other hand, the adhesive strength between the wiring 3 and the plating resist 4 and the adhesive 2 and the adhesive strength between the adhesive 2 and the insulating substrate 1 after the adhesive 2 is cured is 1
It is about 000 gf / cm. Therefore, for example, as shown in FIG. 5, a peeling roller 9 is provided at the exit of the heating furnace 8, and the peeling roller is immediately after the adhesive 2 is completely cured by the heat treatment by the heating furnace 8. When the bending deformation is applied to the temporary substrate 6 at 9, the temporary substrate 6 can be easily peeled off.

Insulating substrate 1 obtained by peeling off the temporary substrate 6,
That is, although not shown, the insulating substrate 1 onto which the wiring 3, the plating resist 4, and the conductive thin film 7 are transferred is wound on a reel and conveyed to the next step. On the other hand, the peeled temporary substrate 6 is wound on another reel, and after being tested for reliability and the like, it is reused.

Next, as shown in FIG. 6, the conductive thin film 7 is removed by etching to expose the wiring 3 and the plating resist 4, and then, for example, the wiring 3 is used.
When the terminal plating 5 is formed on the exposed surface of, the wiring board as shown in FIGS. 1 and 2 is obtained.

At this time, since the conductive thin film 7 to be removed by etching is on the surface, the wiring 3 is etched when the conductive thin film 7 is etched as in the case where the wiring is formed by the conventional semi-additive method. It is possible to prevent the flatness of the surface of the wiring from being deteriorated and reduce the variation in the thickness of the wiring 3. Therefore, the stability when mounting the semiconductor chip is improved, and the deterioration of connection reliability can be prevented.

Further, since the side surface of the wiring 3 is in close contact with the plating resist 4, the etching liquid is applied to the bonding interface between the wiring 3 and the insulating substrate 1 when the conductive thin film 7 is etched. Without entering, it is possible to prevent the wiring 3 from peeling off due to a decrease in adhesive strength between the wiring 3 and the insulating substrate 1. Therefore, it becomes easier to reduce the width CW of the wiring 3 as compared with the case where the wiring is formed by the conventional semi-additive method. For example, the conductor pitch CP is 40 μm.
This facilitates application to the following wiring board manufacturing method.

Further, at this time, since the side surface of the wiring 3 is in close contact with the plating resist 4, it is possible to prevent the side surface of the wiring 3 from being etched by the etching solution, and the wiring is formed by the conventional subtractive method. It is possible to prevent the wiring from being thinned or damaged as in the case of. Therefore, wiring 3
It is possible to reduce the variation in the shape of the wiring 3 when the width of the wiring is narrowed and the wiring pattern is miniaturized, and it is possible to prevent the reliability of the electrical characteristics such as the high frequency characteristic and the resistance value from decreasing.

Further, unlike the case where the wiring is formed by the subtractive method, since the wiring cannot be undercut, the upper width of the wiring does not become thin. Therefore, it is possible to prevent deterioration of connection reliability with the external electrodes of the semiconductor chip.

As described above, according to the method of manufacturing the wiring board of this embodiment, the wiring 3 is formed on the insulating temporary board 6 by the semi-additive method, and then the temporary board 6 is formed.
By adhering and transferring the conductive thin film 7, the wiring 3, and the plating resist 4 on the insulating substrate 1, the conductive thin film 7 to be removed by etching comes to the surface. Therefore, it is possible to prevent the flatness of the surface of the wiring 3 from being deteriorated when the conductive thin film 7 is etched as in the case where the wiring is formed by the conventional semi-additive method, and the thickness of the wiring 3 is reduced. It is possible to reduce variations, improve stability when mounting a semiconductor chip, and prevent deterioration of connection reliability.

Further, since the side surface of the wiring 3 is in close contact with the plating resist 4, the etching liquid is applied to the bonding interface between the wiring 3 and the insulating substrate 1 when the conductive thin film 7 is etched. Without entering, it is possible to prevent the wiring 3 from peeling off due to a decrease in adhesive strength between the wiring 3 and the insulating substrate 1. Therefore, it becomes easier to reduce the width CW of the wiring 3 as compared with the case where the wiring is formed by the conventional semi-additive method. For example, the conductor pitch CP is 40 μm.
This facilitates application to the following wiring board manufacturing method.

At this time, since the side surface of the wiring 3 is in close contact with the plating resist 4, it is possible to prevent the side surface of the wiring 3 from being etched by an etching solution, and the wiring is formed by the conventional subtractive method. It is possible to prevent the wiring from being thinned or damaged as in the case of. Therefore, wiring 3
When the wiring pattern is miniaturized by narrowing the width of the wiring, it is possible to reduce the variation in the shape of the wiring 3, and it is possible to prevent the deterioration of the electrical reliability.

Further, unlike the case where the wiring is formed by the subtractive method, since the wiring cannot be undercut, the upper width of the wiring does not become thin. Therefore, it is possible to prevent deterioration of connection reliability with the external electrodes of the semiconductor chip.

Further, by forming the wiring 3 by electrolytic copper plating, the wiring 3 can be easily formed in a short time as compared with the conventional full additive method, that is, the case where the wiring is formed by electroless copper plating. You can Therefore, compared to the case where wiring is formed by the conventional full additive method,
The manufacturing cost of the wiring board can be reduced.

When the conductive thin film 7 is formed by sputtering, no catalyst is used unlike electroless copper plating, so that insulation failure or short circuit due to electromigration does not occur. Even when the conductive thin film 7 is formed by electroless plating, the unnecessary catalyst can be removed by washing after the unnecessary conductive thin film 7 is removed, resulting in insulation failure or short circuit due to electromigration. Hateful. Therefore, as compared with the case where the wiring is formed by the conventional full additive method, the gap C of the wiring 3 is formed.
It is possible to prevent a decrease in electrical reliability when S is narrowed, and it is easy to reduce the conductor pitch.

Further, the temporary substrate 6 can be used for manufacturing the wiring substrate again after the wiring 3, the plating resist 4, and the conductive thin film 7 are transferred to the insulating substrate 1 and then recovered. It is possible to suppress an increase in the manufacturing cost of the wiring board.

In the method of manufacturing the wiring board of this embodiment, the conductive thin film 7 is adhered on the insulating temporary substrate 6,
After the wiring 3 is formed by the semi-additive method, in the step of adhering the insulating substrate 1 by using a thermosetting resin, the adhesive force between the conductive thin film 7 and the temporary substrate 6 is reduced. Before the bonding, the adhesive force between the temporary substrate 6 and the conductive thin film 7 is large. Therefore, as compared with the conventional transfer method using a metal plate, the conductive thin film 7 is less likely to be peeled off even when the temporary substrate 6 is bent and deformed. Therefore, a large number of wiring boards having the same pattern can be produced at once.

Further, in the method for manufacturing the wiring board of the present embodiment, the thermosetting resin is used as the adhesive 2, but the adhesive 2 is not limited to this, and for example, a thermoplastic resin may be used. In this case, when a thermoplastic polyimide resin is used as the adhesive 2, for example, when the insulating substrate 1 is bonded to the temporary substrate 6 on which the wiring 3 is formed, the insulating substrate 1 and the temporary substrate 6 are bonded together. Since the thermoplastic resin is softened by heating it to about 300 degrees, the adhesion between the temporary substrate 6 and the conductive thin film 7 is lowered by the heating. Therefore, the temporary substrate can be easily peeled off after the step of adhering the insulating substrate 1.

The adhesive 2 is not limited to the thermosetting resin or the thermoplastic resin. For example, as the adhesive 2, the adhesive strength between the wiring 3 and the adhesive 2 and the plating resist 4 are used. It is also possible to use a material in which the adhesive strength between the adhesive 2 and the adhesive 2 is stronger than the adhesive force between the temporary substrate 6 and the conductive thin film 7 or the adhesive force. At this time, as the adhesive 2, a material having a high adhesive strength with the plating resist 4 is preferable, and for example, an epoxy adhesive can be considered. Further, at this time, the epoxy adhesive does not need to be thermosetting or thermoplastic, for example, a photocurable resin that is cured by irradiation with light such as ultraviolet rays,
It may be an adhesive that cures at room temperature. In that case, the insulating substrate 1 can be bonded without performing the heat treatment, and the temporary substrate 6 can be easily peeled off.

7 to 9 are schematic views for explaining an application example of the method for manufacturing a wiring board described in the above embodiment. FIG. 7 is a plan view of the wiring board, and FIGS. 8 and 9 are drawings. FIG. 9 is a plan view for explaining the method for manufacturing the wiring board shown in FIG. 7.

The wiring board as described in the above embodiment is
This is a wiring board (interposer) used for COF type semiconductor devices mainly applied to driver ICs of liquid crystal displays. Since the wiring board 3 is becoming finer, the insulating board 1 is becoming thinner. In order to prevent bending of the insulating substrate 1 and breakage of the tape, as shown in FIG. 7, the reinforcing conductor 10 is provided in the longitudinal end portion of the insulating substrate 1, in other words, in the region where the sprocket hole 1A is provided.
Is often provided.

In such a case, when the wiring 3 is formed on the temporary substrate 6 in accordance with the manufacturing method described in the above embodiment, the reinforcing conductor 10 is also formed, and It may be transferred to the insulating substrate 1 together with the wiring 3.

At this time, the insulating substrate 1 is, for example, as shown in FIG. 8, a region 10 which is actually used as a wiring substrate.
1. A wide substrate having an ear portion 102 provided with an opening 1B for positioning when forming a wiring substrate is used on the outside of 1, and is aligned and bonded using a CCD camera or the like,
After transferring the wiring 3 and the reinforcing conductor 10 to the insulating substrate 1, as shown in FIG. 9, after punching a predetermined position on the reinforcing conductor 10 with, for example, a die to form an opening 1A, By cutting the ear portion 102 of the insulating substrate 1, a wiring substrate as shown in FIG. 7 can be obtained.

FIG. 10 is a schematic view for explaining a modified example of the method for manufacturing the wiring board of the above embodiment.

In the above embodiment, an insulating substrate such as a polyimide tape is used as the temporary substrate 6, and the temporary substrate 6 is used.
After the conductive thin film 7 is formed on the upper surface, the adhesive force between the temporary substrate 6 and the conductive thin film 7 is reduced by heat treatment to peel the conductive thin film 7, but the present invention is not limited to this. A metal substrate 6 ′ such as stainless steel or titanium as shown in FIG. 10A may be used.

Since the stainless steel and titanium have low adhesion to copper and are used as a base material when forming an electrolytic copper foil, as shown in FIG. 10 (b), the metal substrate The wiring 3 can be formed by directly electroplating copper on 6 '.

Thereafter, as described in the above embodiment, the insulating substrate 1 is adhered using the adhesive 2, the metal substrate 6'is peeled off, and the wiring 3 and the plating resist 4 are removed from the insulating substrate. Transfer to 1.

At this time, since the wiring 3 and the plating resist 4 are directly formed on the metal substrate 6 ', the conductive thin film 7 is formed as described in the method for manufacturing the wiring substrate of the above embodiment. The step of forming and the step of etching can be omitted, and the manufacturing cost of the wiring board can be reduced.

When the metal substrate 6'is used, the surface 6A 'of the metal substrate 6'on which the wiring 3 is to be formed in order to easily separate the plating resist 4 and the metal substrate 6'. Is mirror-finished.

Although the present invention has been specifically described based on the above embodiment, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the invention. Of course.

For example, in the above-mentioned embodiments, application examples, and modified examples, a single-sided wiring board used for a COF type semiconductor device has been described as an example. It may be applied to the formation of the material of the wiring board.

The manufacturing method is not limited to the reel-to-reel method described in the above embodiment, but may be applied to a single-wafer manufacturing method using a flat plate-shaped or strip-shaped temporary substrate.

[0095]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1) In the method of manufacturing a wiring board, it is possible to reduce the defective shape of the wiring when the wiring pitch is made fine.

(2) In the method of manufacturing a wiring board, it is possible to improve the bonding reliability of the wiring when the wiring pitch is made fine.

(3) A wiring board having a fine wiring pitch can be mass-produced at one time.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a schematic configuration of an example of a wiring board according to the present invention, and is a plan view of the wiring board.

FIG. 2 is a schematic diagram showing a schematic configuration of an example of a wiring board according to the present invention, and is a cross-sectional view taken along line AA ′ of the wiring board shown in FIG.

FIG. 3 is a schematic diagram for explaining a method of manufacturing a wiring board according to an embodiment of the present invention, and FIGS.
3B, FIG. 3C, and FIG. 3D are cross-sectional views of the process of forming the wiring on the temporary substrate.

FIG. 4 is a schematic diagram for explaining the method for manufacturing the wiring board of the present embodiment, and FIGS. 4A and 4B are cross-sectional views of a process of transferring the wiring to the insulating substrate.

FIG. 5 is a schematic view for explaining the method for manufacturing the wiring board of the present embodiment, which is a cross-sectional view of the step of transferring the wiring to the insulating substrate.

FIG. 6 is a schematic diagram for explaining the method for manufacturing the wiring board of the present embodiment, which is a cross-sectional view of a step of removing the conductive thin film.

FIG. 7 is a schematic view for explaining an application example of the method for manufacturing a wiring board according to the embodiment, and is a plan view of the wiring board.

8 is a schematic diagram for explaining an application example of the method for manufacturing a wiring board according to the embodiment, and a plan view for explaining a method for manufacturing the wiring board shown in FIG. 7. FIG.

9 is a schematic view for explaining an application example of the method for manufacturing a wiring board according to the embodiment, and a plan view for explaining the method for manufacturing the wiring board shown in FIG. 7. FIG.

10A and 10B are schematic views for explaining a modified example of the method for manufacturing a wiring board according to the embodiment, FIG. 10A is a sectional view of a temporary board, and FIG. 10B is a step of forming wiring. FIG.

FIG. 11 is a schematic diagram for explaining parameters when a wiring pattern is miniaturized.

FIG. 12 is a schematic cross-sectional view for explaining a conventional wiring forming method by a subtractive method.

FIG. 13 is a schematic diagram for explaining a problem of the conventional subtractive method.

FIG. 14 is a schematic cross-sectional view for explaining a wiring forming method by a conventional full additive method.

FIG. 15 is a schematic diagram for explaining a problem of the conventional full additive method.

FIG. 16 is a schematic cross-sectional view for explaining a conventional wiring forming method by a semi-additive method.

FIG. 17 is a schematic diagram for explaining a problem of the conventional semi-additive method.

[Explanation of symbols]

1 ... Insulating substrate, 1A, 1B ... Opening (perforation hole), 101 ... Area used as wiring substrate, 102 ...
Ears, 2 ... Adhesive, 3 ... Wiring (electrolytic copper plating film), 4 ...
Resist (plating resist), 5 ... Terminal plating, 6 ... Temporary substrate, 6 '... Metal substrate, 7 ... Conductive thin film, 8 ... Heating furnace,
9 ... Peeling roller, 10 ... Reinforcing conductor, 11 ... Wiring, 1
1A ... end of wiring, 12 ... copper foil (conductive thin film), 12A
... residual etching, 13 ... resist (etching resist), 14 ... adhesive, 15 ... catalyst, 16 ... electroless copper plating film, 16 '... electromigration, 17 ... electrolytic copper plating film, CW ... wiring width (conductor width) ), CS ... Wiring gap (conductor gap), CP ... Wiring pitch (conductor pitch), CT ... Wiring thickness (conductor thickness).

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 5E343 AA03 AA12 AA33 AA38 BB02                       BB05 BB24 BB66 CC01 CC67                       DD43 DD56 DD63 ER49 GG08                 5F044 KK03 MM03 MM48

Claims (6)

[Claims] 1. A method of manufacturing a wiring substrate, wherein wiring is formed on one surface of an insulating substrate, a step of forming a conductive thin film on the surface of a temporary substrate, and a resist (plating resist) is formed on the conductive thin film. A step of forming a wiring having a predetermined pattern by electrolytic copper plating, a step of adhering an insulating substrate to a surface of the temporary substrate on which the wiring is formed, a step of peeling the temporary substrate, and the wiring and the resist. And a step of transferring the conductive thin film to the insulating substrate, and a step of removing the conductive thin film, the method for manufacturing a wiring board. 2. Prior to the step of peeling off the temporary substrate, the adhesion force or the adhesion force between the temporary substrate and the conductive thin film is lower than the adhesion force between the insulating substrate, the wiring and the resist. The method for manufacturing a wiring board according to claim 1, wherein heat treatment is performed. 3. In the step of adhering the insulating substrate, the adhesion force between the temporary substrate and the conductive thin film is increased by heating when adhering the insulating substrate using a thermosetting resin and curing the thermosetting resin. The adhesive force is reduced, and the adhesive force is decreased.
A method for manufacturing a wiring board according to. 4. In the step of adhering the insulating substrate, the provisional substrate and the conductive thin film are adhered to each other by using a thermoplastic resin, the thermoplastic resin is softened, and the provisional substrate and the conductive thin film are heated by applying heat to the temporary substrate. 3. The method for manufacturing a wiring board according to claim 2, wherein the adhesive force or the adhesive force is reduced. 5. A tape-shaped insulating substrate that is long in one direction is used as the temporary substrate, and in each of the steps, while the tape-shaped insulating substrate wound on a reel is being wound on another reel. It carries out, The manufacturing method of the wiring board of any one of Claim 1 thru | or 4 characterized by the above-mentioned. 6. A wiring board in which wiring is provided on one surface of an insulating substrate via an adhesive, and a plating resist is provided between the wirings, wherein the wiring and the plating resist are the insulating substrate. A wiring board, which is obtained by transferring a material provided on a conductive thin film provided on the surface of a temporary substrate prepared separately from the temporary board, to the one surface of the insulating substrate via an adhesive.