JP3879516B2 - Wiring board manufacturing method and wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a wiring board and a wiring board, and more particularly to a technique that is effective when applied to a method for manufacturing a single-sided wiring board for forming fine wiring used in a COF (Chip On Film) type semiconductor device. Is.
[0002]
[Prior art]
Conventionally, in a method of manufacturing a wiring substrate, a method of forming a predetermined pattern of wiring on the surface of an insulating substrate includes a subtractive process, a full additive process, and a semi-additive process (semi-additive process). additive process).
[0003]
Among the wiring boards, for example, interposers used in semiconductor devices such as BGA (Ball Grid Array) and CSP (Chip Size Package), in other words, matching of external electrodes of a semiconductor chip and terminals on a motherboard or grid conversion In the wiring board that performs the above, the external terminals (bonding pads) are densified due to the miniaturization and high functionality of the semiconductor chip, and accordingly, fine pitch and high density wiring is required. ing.
[0004]
In particular, in a wiring board used for a COF type semiconductor device such as a driver IC for a liquid crystal display, the center of adjacent wirings 11 in the wiring 11 provided on the surface of the insulating substrate 1 as shown in FIG. A distance between conductors (conductor pitch) CP of about 20 μm to 30 μm is being demanded.
[0005]
For miniaturization and high density of the conductor pitch CP, the width (conductor width) CW of the wiring 11 and the distance (conductor gap) CS between the end portions 11A of the adjacent wirings 11 as shown in FIG. It is necessary to make it narrower, and various improvements have been added to the respective wiring forming methods.
[0006]
As shown in FIG. 12 (a), the subtractive method has a copper foil (conductive thin film) such as an electrolytic copper foil or a rolled copper foil on the surface of an insulating substrate 1 such as a polyimide tape or a glass cloth base epoxy resin substrate. ) 12 is used to form 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. As shown in c), the wiring 11 is formed by removing unnecessary portions of the copper foil 12 by etching.
[0007]
In the subtractive method, when the copper foil 12 is etched, the side surface portion of the wiring 11 is also etched. At this time, the etching amount of the side portion of the wiring 11 varies depending on the density of the wiring 11 to be formed and the linearity of the end portion 11A of the wiring 11 is deteriorated as shown in FIG. It tends to be thicker or thinner than the predetermined conductor width CW. Further, if there is a lattice defect or the like in the copper foil 12, the etching rate is locally increased or decreased, so that a defect NC or a protrusion is easily formed in the wiring 11. Therefore, the shape of the wiring 11 becomes uneven and the electrical characteristics are likely to change.
[0008]
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, the etching residue of the copper foil 12 is left as shown in FIG. 12A is likely to occur.
[0009]
For these reasons, it is difficult to apply the subtractive method to a method for manufacturing a wiring board having a conductor pitch CP of 40 μm or less, for example.
[0010]
The full additive method is a method in which the wiring 11 is formed directly on the insulating substrate 1 only by electroless plating. As shown in FIG. 14A, an adhesive 14 is applied to the surface of the insulating substrate 1. And a catalyst 15 such as palladium (Pd) is applied 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 made of the electroless copper plating film 16 is formed. At this time, the plating resist 4 is generally used as it is as a solder protective film (permanent mask).
[0011]
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 below the plating resist 4. Therefore, when the interval between the adjacent wirings 11 is narrowed, the adjacent wirings 11 are easily short-circuited. . Here, FIG. 15 is a cross-sectional view corresponding to FIG. 14B, but the hatching of the plating resist 4 is omitted for easy understanding of the drawing.
[0012]
Therefore, it is difficult to apply the full additive method to a method for manufacturing a wiring board having a conductor pitch CP of 40 μm or less, for example.
[0013]
Further, in the full additive method, since the wiring 11 is formed by electroless plating, it is possible to prevent the conductor from being thickened or thinned, as in the subtractive method, or protrusions or defects. Since the process for forming 16 is complicated and takes time, the manufacturing cost tends to increase.
[0014]
On the other hand, in the semi-additive method, as shown in FIG. 16A, a thin conductive thin film 7 having a thickness of about 3 μm is formed on the surface of the insulating substrate 1 by, for example, electroless plating or sputtering. As shown in FIG. 16B, a resist (plating resist) 4 is formed on the conductive thin film 7 so that a wiring pattern portion to be formed is opened, and the conductive thin film 7 is used as an electrode (underlying). For example, an electrolytic copper plating film 17 is formed. Thereafter, the plating resist 4 is removed, and as shown in FIG. 16C, the exposed portion of the conductive thin film 7 is removed by etching treatment, and the conductive thin film 7 and the electrolytic copper plating film 17 are formed. This is a method of forming the wiring 11.
[0015]
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 can be etched in a short time. Thinning, protrusions and defects can be prevented. Further, since the conductive thin film 7 is thin and can be easily removed by etching, the adjacent wirings 11 can be reliably separated, and the adjacent wirings 11 are not easily short-circuited due to the etching failure.
[0016]
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. Short circuit between adjacent wirings 11 due to migration is unlikely to occur. Further, when the conductive thin film 7 is formed by sputtering, no catalyst is required, so that short circuit between adjacent wirings due to electromigration does not occur.
[0017]
Therefore, the semi-additive method is easier to apply to, for example, 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.
[0018]
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 by electrolytic copper plating on a metal plate such as a stainless steel plate, and the wiring pattern There has been proposed a method (transfer method) in which an insulating substrate is bonded to the metal plate and the metal plate is peeled off to transfer the wiring pattern onto the insulating substrate.
[0019]
In the case of the transfer method, since a wiring can be formed directly on the metal plate, unnecessary conductor removal by etching treatment, such as the subtractive method or the semi-additive method, or the full additive method is performed. No catalyst 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]
[Problems to be solved by the invention]
However, in the conventional technique, when the wiring 11 is formed by the semi-additive method, the conductive thin film 7 serving as a base is sufficiently thinner than the thickness of the electrolytic copper plating film 17. 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. 17A, the surface of the wiring 11, that is, the electrolytic copper plating. There is a problem that the flatness of the surface 17A of the film 17 is deteriorated. Further, there is a problem that the etching amount of the surface 17A of the electrolytic copper plating film varies, and the thickness of the wiring 11 is likely to vary.
[0021]
If the flatness of the surface 17A of the electrolytic copper plating film is deteriorated or the thickness of the wiring 11 varies, the stability of the semiconductor chip is deteriorated when the semiconductor chip is mounted, and the connection reliability is improved. There was a problem of lowering.
[0022]
Further, although not as much as when the wiring is formed by the subtractive method, the side surface of the wiring (electrocopper plating film 17) is also etched, so that there is a possibility that the wiring 11 may be thinned or broken. there were.
[0023]
In recent years, in order to make the surface 17A of the electrolytic copper plating film difficult to be etched during quick etching, the conductive thin film 7 is etched more than copper, such as nickel copper alloy or nickel chromium alloy. There is a method using a high-speed conductor or a conductor that dissolves in a solution in which copper is difficult to dissolve. In that case, the conductive thin film 7 is selectively etched. Undercut 7A is likely to occur in thin film 7.
[0024]
When the undercut 7A is generated in the conductive thin film 7, the contact surface between the wiring 11 (electrocopper plating film 17) and the insulating substrate 1 is narrowed and the adhesion is reduced. For example, the peel strength of the wiring 11 is reduced. There is a problem that the wiring 11 is easily peeled off. For this reason, if the width CW of the wiring 11 is reduced, it becomes difficult to ensure the adhesion reliability between the wiring 11 and the insulating substrate 1. Therefore, when the conductor pitch CP is further refined, the semi-additive is reduced. There was a problem that it became difficult to apply the law.
[0025]
Further, in the case of a method of manufacturing a wiring board to which the transfer method is applied, a material having low adhesion to the wiring is used as the metal plate, and when an external force such as bending is applied to the metal plate, The wiring is easily peeled off. Further, when the width (conductor width) CW of the wiring becomes narrow, the adhesion between the wiring and the metal plate becomes small, and the wiring is easily peeled off. For this reason, when the wiring board is formed by the reel to reel method used in a manufacturing method such as TCP (Tape Carrier Package), there is a problem that it is difficult to apply the transfer method.
[0026]
In addition, in the case of the transfer method, since it is difficult to apply the reel-to-reel method, there is a problem that it is difficult to produce a large number of wiring boards having the same pattern at a time, and it is difficult to reduce the manufacturing cost of the wiring board.
[0027]
An object of the present invention is to provide a technique capable of reducing a defective shape of a wiring when a wiring pitch is miniaturized in a method for manufacturing a wiring board.
[0028]
Another object of the present invention is to provide a technique capable of improving the bonding reliability of wiring when the wiring pitch is reduced in the method for manufacturing a wiring board.
[0029]
Another object of the present invention is to provide a technique capable of mass-producing a wiring board with a fine wiring pitch at a time.
[0030]
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]
[Means for Solving the Problems]
The outline of the invention disclosed in the present application will be described as follows.
[0032]
  (1) In a method for manufacturing a wiring board in which wiring is formed on one surface of an insulating substrate,Corresponding to the insulating substrateForming a conductive thin film on the surface of the temporary substrate, and on the conductive thin film;The part that does not form wiringForm a resist (plating resist) onAfter,In the part where wiring is formed on the conductive thin filmA step of forming wiring of a predetermined pattern by electrolytic copper plating, and the temporary substrateBeforeWiringAnd the resistUsing adhesive on the surface on which theAboveBonding the insulating substrate; peeling the temporary substrate; transferring the wiring and the resist; and the conductive thin film to the insulating substrate;From the surface of the wiring and the resistAnd a step of removing the conductive thin film.
[0033]
  According to the means of (1), after the wiring is formed on the temporary substrate using a semi-additive method, the wiringAnd the resist (plating resist) and the conductive thin film on the insulating substrateBy transferring, the conductive thin film to be removed by etching or the like is exposed on the surface. Therefore, it becomes easy to remove the conductive thin film.
[0034]
Further, when the conductive thin film is removed by, for example, etching, 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. Therefore, even when the width of the wiring is narrowed, variations in the shape of the wiring and a decrease in the adhesive force between the wiring and the insulating substrate can be prevented.
[0035]
Further, as described in the above means (1), by exposing the conductive thin film to the surface, the limit of miniaturization of the wiring pitch depends only on the accuracy in forming the plating resist. Therefore, for example, application to a manufacturing method of a wiring board having a wiring pitch of 40 μm or less becomes easy.
[0036]
In the means of (1), the insulating substrate is bonded using an adhesive, and before the step of peeling off the temporary substrate, the adhesion or adhesive force between the temporary substrate and the conductive thin film is changed to the insulating substrate. After the wiring is formed on the temporary substrate by performing heat treatment so as to be lower than the adhesive force between the substrate and the wiring and the resist (plating resist), the conveyance until the step of bonding the insulating substrate is performed. While being able to prevent the wiring from being peeled off, the temporary substrate can be easily peeled off after the insulating substrate is bonded.
[0037]
At this time, the step of adhering the insulating substrate uses a thermosetting resin as the adhesive, and the adhesive force or adhesion between the temporary substrate and the conductive thin film by heating when the thermosetting resin is cured. It is preferable to reduce the force. In this case, the step of peeling the temporary substrate can be performed immediately after the step of bonding the insulating substrate, and there is no need to separately provide a step of peeling the temporary substrate.
[0038]
The adhesive is not limited to the thermosetting resin, and for example, a thermoplastic resin may be used. Also in this case, when the insulating substrate is bonded, the insulating substrate and the temporary substrate are heated to soften the thermoplastic resin, so that the adhesive force or bonding between the temporary substrate and the conductive thin film is caused by heating. If the force is reduced, the step of peeling the temporary substrate can be performed immediately after the step of bonding the insulating substrate, and there is no need to separately provide the step of peeling the temporary substrate.
[0039]
In addition, an insulating substrate is used as the temporary substrate, the insulating substrate is bonded using a thermosetting resin or a thermoplastic resin, and the adhesive force between the temporary substrate and the conductive thin film is increased by heating at the time of bonding or By reducing the adhesive force, the wiring is unlikely to peel off even when bending deformation is applied to the temporary substrate before the step of bonding the insulating substrate. Therefore, a reel-to-reel method applied to a 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 step is wound on a reel. Since the tape-like insulating substrate can be carried out while being wound on another reel, a large number of wiring substrates having the same pattern can be produced at a time.
[0040]
Further, in the step of bonding the insulating substrate, the thermosetting resin or the thermoplastic resin is used as the adhesive, and when the heat treatment is performed, the adhesion between the temporary substrate and the conductive thin film is reduced. In addition, for example, the adhesion between the wiring and the insulating substrate and the adhesion between the plating resist and the insulating substrate are stronger than the adhesion or adhesion between the temporary substrate and the conductive thin film. The insulating substrate may be bonded using an agent. In that case, the wiring can be transferred without performing the heat treatment.
[0041]
  (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. The wiring and the plating resist are the same as the insulating substrate. What was provided on the conductive thin film provided on the surface of the temporary substrate prepared separately was transferred to one surface of the insulating substrate via an adhesive.The same adhesive as the adhesive interposed between the insulating substrate and the wiring is interposed between the insulating substrate and the plating resist.Wiring board.
[0042]
  According to the means of (2), the wiring and the plating resist provided on the temporary substrate areAdhering to the insulating substrate with an adhesive, on the insulating substrateBy transferring, it is possible to obtain a wiring board with less variation in wiring shape and shape defects and high reliability in electrical characteristics. Further, since there are few variations in the wiring shape and shape defects, the wiring can be easily miniaturized, and a small and high-density wiring board can be obtained. Therefore, it becomes easy to reduce the size and increase the functionality of the semiconductor device using the wiring board.
[0043]
Hereinafter, the present invention will be described in detail together with embodiments (examples) with reference to the drawings.
[0044]
In all the drawings for explaining the embodiments, parts having the same function are given the same reference numerals, and repeated explanation thereof is omitted.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Before describing an embodiment according to the present invention, an example of a wiring board according to the present invention will be described first.
[0046]
1 and 2 are schematic views showing a schematic configuration 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 line AA ′ of the wiring board shown in FIG. FIG.
[0047]
1 and 2, 1 is an insulating substrate, 1A is an opening (perforation hole), 2 is an adhesive, 3 is a wiring (electrocopper plating film), 4 is a plating resist (solder protective film), and 5 is terminal plating. It is.
[0048]
The main thing of the wiring board concerning this invention is a wiring board (interposer) used for COF type semiconductor devices, such as a driver IC of a liquid crystal display, for example, and wiring (conductor pattern) is provided only on one side of an insulating board. As shown in FIGS. 1 and 2, wiring 3 having a predetermined pattern is provided on the surface of a film-like insulating substrate 1 via an adhesive 2.
[0049]
Further, as shown in FIG. 2, the wirings 3 are insulated by a plating resist (solder protective film) 4, and terminal platings 5 are provided on the surfaces of the wirings 3. 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.
[0050]
The insulating substrate 1 is a tape material that is long in one direction, such as a polyimide tape, for example, and an opening (perforation hole) 1A for alignment is provided along the end in the longitudinal direction. Yes.
[0051]
When a semiconductor device is formed using the wiring board, a semiconductor chip is mounted in each of the chip mounting regions L1 on the wiring board, and the wiring 3 and external terminals (bonding pads) of the semiconductor chip are formed with a sealing resin. After sealing the connection part, the individualized region L2 is cut.
[0052]
Semiconductor devices using the wiring substrate are becoming smaller and higher in density, and the pitch (conductor pitch) of the wiring 3 as shown in FIG. 11 is about 20 μm to 30 μm. For this reason, it is necessary to reduce the width of the wiring 3 (conductor width) and the distance between the ends of adjacent wirings (conductor gap) while preventing a decrease in electrical reliability.
[0053]
Hereinafter, an embodiment of a method of manufacturing a wiring board that prevents a reduction in electrical reliability when the conductor width and the conductor gap are narrowed and enables miniaturization of a wiring pattern will be described.
[0054]
(Example)
3 to 6 are schematic views for explaining a method of manufacturing a wiring board according to an embodiment of the present invention. FIGS. 3 (a), 3 (b), 3 (c), and 3 4D is a cross-sectional view of a process for forming a wiring on a temporary substrate, FIGS. 4A, 4B, and 5 are cross-sectional views of a process for transferring the wiring to an insulating substrate, and FIG. It is sectional drawing of the process of removing a conductive thin film.
[0055]
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.
[0056]
Hereinafter, the method for manufacturing the wiring board of this embodiment will be described with reference to FIGS.
[0057]
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 as the temporary substrate 6, and a deposited film such as copper, a nickel copper alloy, or a nickel chromium alloy is formed on the surface of the temporary substrate 6 by sputtering or the like as the conductive thin film 7. . At this time, the adhesive strength (adhesion force) between the temporary substrate 6 and the conductive thin film 7 is approximately 100 gf / cm to 500 gf / cm, depending on the combination of the temporary substrate 6 and the conductive thin film 7.
[0058]
Also, at this time, the temporary substrate 6 is a substrate that is long in one direction, for example, used in the manufacture of TCP, and the steps of forming the conductive thin film 7 and the following steps are the reel It is assumed that the two-reel system is used, that is, the temporary substrate 6 wound around the reel is being wound around another reel.
[0059]
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 used as a cathode. As shown in FIG. 3C, wiring (electrocopper plating film) 3 is formed by electrolytic copper plating.
[0060]
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 resist such as polymethyl methacrylate (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. In addition, the distance CS can be reduced to about 5 μm.
[0061]
Further, even when a negative dry film is used as the plating resist 4, since the exposure limit that can ensure the accuracy of the pattern to be formed is about 15 μm, the width CW of the wiring 3 and the interval CS of the wiring 3 are respectively It can be narrowed to about 15 μm.
[0062]
Further, when the wiring 3 is formed by the electrolytic copper plating, the wiring 3 can be formed in a shorter time compared to the full additive method in which the wiring is formed by electroless copper plating.
[0063]
At this time, the growth surface 3A of the wiring 3 has a convex shape as shown in FIG. 3C due to the composition of the additive contained in the plating bath used, or a concave shape although not shown. It may become. Therefore, if necessary, as shown in FIG. 3D, the growth surface 3A of the wiring 3 is polished to flatten the surface.
[0064]
Next, as shown in FIG. 4A, after the insulating substrate 1 is bonded to the surface on which the wiring 3 and the plating resist 4 are formed using the adhesive 2, as shown in FIG. 4B. Then, 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.
[0065]
At this time, for example, when a thermosetting resin such as an epoxy resin or a polyimide resin is used as the adhesive 2, the temporary substrate 6 and the conductive thin film in the heat treatment for curing the adhesive 2 are used. 7 is reduced, for example, from about 50 gf / cm to about 200 gf / cm. On the other hand, after the adhesive 2 is cured, 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 are about 1000 gf / cm. is there. Therefore, for example, as shown in FIG. 5, a peeling roller 9 is provided at the outlet of the heating furnace 8, and immediately after the adhesive 2 is completely cured by heat treatment in the heating furnace 8, the peeling roller is provided. When bending deformation is applied to the temporary substrate 6 in 9, the temporary substrate 6 can be easily peeled off.
[0066]
The insulating substrate 1 from which the temporary substrate 6 has been peeled off, that is, the insulating substrate 1 to which the wiring 3 and the plating resist 4 and the conductive thin film 7 have been transferred, is not shown, but is wound around a reel. Then, it is conveyed to the next process. On the other hand, the temporary substrate 6 that has been peeled off is wound up on another reel, and is reused after being tested for reliability.
[0067]
Next, as shown in FIG. 6, after removing the conductive thin film 7 by an etching process to expose the wiring 3 and the plating resist 4, for example, terminal plating 5 is formed on the exposed surface of the wiring 3. Then, a wiring board as shown in FIGS. 1 and 2 is obtained.
[0068]
At this time, since the conductive thin film 7 to be removed by etching is on the surface, the surface of 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 from deteriorating and to reduce the variation in the thickness of the wiring 3. Therefore, the stability when the semiconductor chip is mounted is improved, and the connection reliability can be prevented from being lowered.
[0069]
Further, since the side surface of the wiring 3 is in close contact with the plating resist 4, when the conductive thin film 7 is etched, the etching solution enters the bonding interface between the wiring 3 and the insulating substrate 1. In other words, the wiring 3 can be prevented from being peeled off due to a decrease in the adhesive strength between the wiring 3 and the insulating substrate 1. Therefore, it becomes easier to reduce the width CW of the wiring 3 compared to the case where the wiring is formed by the conventional semi-additive method, and for example, it can be easily applied to a method of manufacturing a wiring board having a conductor pitch CP of 40 μm or less. Become.
[0070]
At this time, since the side surface of the wiring 3 is in close contact with the plating resist 4, the side surface of the wiring 3 can be prevented from being etched with an etching solution, and the wiring is formed by a conventional subtractive method. In this way, it is possible to prevent the wiring from being thinned or missing. Therefore, the variation in the shape of the wiring 3 when the width of the wiring 3 is narrowed and the wiring pattern is miniaturized can be reduced, and the reliability of electrical characteristics such as high-frequency characteristics and resistance values is reduced. Can be prevented.
[0071]
In addition, since the wiring cannot be undercut like when the wiring is formed by the subtractive method, the upper width of the wiring is not reduced. Therefore, it is possible to prevent a decrease in connection reliability with the external electrode of the semiconductor chip.
[0072]
As described above, according to the method for manufacturing the wiring board of this embodiment, after the wiring 3 is formed on the insulating temporary substrate 6 using the semi-additive method, the conductive thin film on the temporary substrate 6 is formed. 7. By bonding and transferring the wiring 3 and the plating resist 4 to 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. Variations can be reduced, stability when a semiconductor chip is mounted is improved, and deterioration in connection reliability can be prevented.
[0073]
In addition, since the side surface of the wiring 3 is in close contact with the plating resist 4, when the conductive thin film 7 is etched, the etching solution enters the bonding interface between the wiring 3 and the insulating substrate 1. In other words, the wiring 3 can be prevented from being peeled off due to a decrease in the adhesive strength between the wiring 3 and the insulating substrate 1. Therefore, it becomes easier to reduce the width CW of the wiring 3 compared to the case where the wiring is formed by the conventional semi-additive method, and for example, it can be easily applied to a method of manufacturing a wiring board having a conductor pitch CP of 40 μm or less. Become.
[0074]
At this time, since the side surface of the wiring 3 is in close contact with the plating resist 4, the side surface of the wiring 3 can be prevented from being etched with an etching solution, and the wiring is formed by a conventional subtractive method. In this way, it is possible to prevent the wiring from being thinned or missing. Therefore, the variation in the shape of the wiring 3 when the width of the wiring 3 is narrowed and the wiring pattern is miniaturized can be reduced, and a decrease in electrical reliability can be prevented.
[0075]
In addition, since the wiring cannot be undercut like when the wiring is formed by the subtractive method, the upper width of the wiring is not reduced. Therefore, it is possible to prevent a decrease in connection reliability with the external electrode of the semiconductor chip.
[0076]
Further, by forming the wiring 3 by electrolytic copper plating, the wiring 3 can be easily formed in a short time compared to the case of forming the wiring by a conventional full additive method, that is, electroless copper plating. Therefore, the manufacturing cost of the wiring board can be reduced as compared with the case where the wiring is formed by the conventional full additive method.
[0077]
Further, when the conductive thin film 7 is formed by sputtering, a catalyst is not used as in the case of electroless copper plating, so that insulation failure and short circuit due to electromigration do 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. Hateful. Therefore, compared with the case where the wiring is formed by the conventional full additive method, it is possible to prevent a decrease in electrical reliability when the gap CS of the wiring 3 is narrowed, and the conductor pitch can be easily miniaturized.
[0078]
Further, since the temporary substrate 6 can be recovered and used again for manufacturing a wiring board after the wiring 3, the plating resist 4, and the conductive thin film 7 are transferred to the insulating substrate 1. An increase in manufacturing cost can be suppressed.
[0079]
Further, in the method of manufacturing the wiring board according to the present embodiment, the conductive thin film 7 is bonded onto the insulating temporary substrate 6 and the wiring 3 is formed by the semi-additive method, and then the insulating substrate is formed using a thermosetting resin. 1, in order to reduce the adhesive force between the conductive thin film 7 and the temporary substrate 6, the adhesive force between the temporary substrate 6 and the conductive thin film 7 is the step before bonding the insulating substrate 1. Is big. Therefore, compared to the transfer method using a conventional metal plate, the conductive thin film 7 is less likely to be peeled off even if the temporary substrate 6 is subjected to bending deformation. Therefore, a large number of wiring boards having the same pattern can be produced at a time.
[0080]
Further, in the method for manufacturing a wiring board according to the present embodiment, a thermosetting resin is used as the adhesive 2. However, the present invention is not limited thereto, and a thermoplastic resin may be used, for example. In this case, when, for example, a thermoplastic polyimide resin is used as the adhesive 2, the insulating substrate 1 and the temporary substrate 6 are bonded when the insulating substrate 1 is bonded to the temporary substrate 6 on which the wiring 3 is formed. Since the thermoplastic resin is softened by heating to about 300 degrees, the adhesion between the temporary substrate 6 and the conductive thin film 7 is reduced by heating. Therefore, the temporary substrate can be easily peeled off after the step of bonding the insulating substrate 1.
[0081]
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 and the adhesive A material whose adhesive strength with the agent 2 is stronger than the adhesive force or adhesive force between the temporary substrate 6 and the conductive thin film 7 can also be used. At this time, as the adhesive 2, a material having high adhesive strength with the plating resist 4 is preferable, and for example, an epoxy adhesive can be considered. At this time, the epoxy adhesive does not need to be thermosetting or thermoplastic, and is, for example, a photocurable resin that is cured by irradiation with light such as ultraviolet rays or an adhesive that is cured at room temperature. May be. 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.
[0082]
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 shown in FIG. It is a top view for demonstrating the manufacturing method of the printed wiring board.
[0083]
The wiring board as described in the above embodiment is a wiring board (interposer) used for a COF type semiconductor device mainly applied to a driver IC for a liquid crystal display. Since the thickness of the substrate 1 has been reduced, in order to prevent the insulation substrate 1 from being bent and the tape from being cut, as shown in FIG. 7, the longitudinal end of the insulation substrate 1, in other words, the sprocket hole 1A In many cases, the reinforcing conductor 10 is provided in a region where the is provided.
[0084]
In such a case, the reinforcing conductor 10 is formed together with the wiring 3 when the wiring 3 is formed on the temporary substrate 6 in accordance with the manufacturing method described in the embodiment. What is necessary is just to transcribe | transfer to the said insulated substrate 1.
[0085]
At this time, for example, as shown in FIG. 8, the insulating substrate 1 has an ear portion 102 provided with an opening 1B for positioning when forming the wiring board outside the region 101 actually used as the wiring board. 9, after aligning and bonding using a CCD camera or the like and transferring the wiring 3 and the reinforcing conductor 10 to the insulating substrate 1, as shown in FIG. A predetermined position on the conductor 10 is punched out with a mold, for example, to form the opening 1A, and then the ear 102 of the insulating substrate 1 is cut to obtain a wiring board as shown in FIG. it can.
[0086]
FIG. 10 is a schematic diagram for explaining a modification of the method of manufacturing the wiring board according to the embodiment.
[0087]
In the embodiment, an insulating substrate such as a polyimide tape is used as the temporary substrate 6. After the conductive thin film 7 is formed on the temporary substrate 6, the temporary substrate 6 and the conductive thin film 7 are subjected to heat treatment. However, the present invention is not limited to this, and as the temporary substrate 6, for example, a metal substrate 6 ′ such as stainless steel or titanium as shown in FIG. 10A is used. Also good.
[0088]
Since the stainless steel or titanium has a low adhesion to copper and is a material used as a base material when forming an electrolytic copper foil, as shown in FIG. 10B, on the metal substrate 6 ′. The wiring 3 can be formed by direct copper plating.
[0089]
Thereafter, as described in the embodiment, the insulating substrate 1 is bonded using the adhesive 2, the metal substrate 6 ′ is peeled off, and the wiring 3 and the plating resist 4 are transferred to the insulating substrate 1. To do.
[0090]
At this time, since the wiring 3 and the plating resist 4 are directly formed on the metal substrate 6 ′, the step of forming the conductive thin film 7 described in the method of manufacturing the wiring substrate of the embodiment and The etching process can be omitted, and the manufacturing cost of the wiring board can be reduced.
[0091]
When the metal substrate 6 ′ is used, the surface 6A ′ of the metal substrate 6 ′ on which the wiring 3 is formed is mirror-finished so that the plating resist 4 and the metal substrate 6 ′ can be easily peeled off. Keep it.
[0092]
The present invention has been specifically described above based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. .
[0093]
For example, in the above-described embodiments, application examples, and modifications, a single-sided wiring board as used in a COF type semiconductor device has been described as an example. You may apply to formation of material.
[0094]
Further, the manufacturing method is not limited to the reel-to-reel method described in the above embodiment, but can be applied to a single-wafer manufacturing method using a flat or strip-like temporary substrate.
[0095]
【The invention's effect】
Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.
[0096]
(1) In the method for manufacturing a wiring board, it is possible to reduce the shape defect of the wiring when the wiring pitch is reduced.
[0097]
(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 reduced.
[0098]
(3) A large number of wiring boards with a finer wiring pitch can be produced at one time.
[Brief description of the 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.
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 A-A ′ of the wiring board shown in FIG. 1;
FIG. 3 is a schematic diagram for explaining a method of manufacturing a wiring board according to an embodiment of the present invention; FIG. 3 (a), FIG. 3 (b), FIG. 3 (c), and FIG. These are sectional drawings of the process of forming wiring on a temporary substrate.
FIGS. 4A and 4B are schematic views for explaining a method of manufacturing a wiring board according to the present embodiment, and FIGS. 4A and 4B are cross-sectional views illustrating a process of transferring the wiring to an insulating substrate. FIGS.
FIG. 5 is a schematic diagram for explaining a method of manufacturing a wiring board according to the present embodiment, and is a cross-sectional view of a process of transferring the wiring to an insulating substrate.
FIG. 6 is a schematic view for explaining the method of manufacturing the wiring board according to the embodiment, and is a cross-sectional view of a process of removing the conductive thin film.
FIG. 7 is a schematic diagram for explaining an application example of the method of manufacturing the wiring board according to the embodiment, and is a plan view of the wiring board.
8 is a schematic view for explaining an application example of the method for manufacturing the wiring board of the embodiment, and is a plan view for explaining the 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 the wiring board of the embodiment, and is 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 of manufacturing the wiring board according to the embodiment, in which FIG. 10A is a sectional view of a temporary board, and FIG. 10B is a process of forming a wiring; It is sectional drawing.
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 wiring formation method by a conventional subtractive method.
FIG. 13 is a schematic diagram for explaining a problem of a conventional subtractive method.
FIG. 14 is a schematic cross-sectional view for explaining a conventional wiring forming method by a full additive method.
FIG. 15 is a schematic diagram for explaining a problem of a conventional full additive method.
FIG. 16 is a schematic cross-sectional view for explaining a wiring forming method by a conventional semi-additive method.
FIG. 17 is a schematic diagram for explaining a problem of a conventional semi-additive method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulating board | substrate, 1A, 1B ... Opening part (perforation hole), 101 ... Area | region used as a wiring board, 102 ... Ear part, 2 ... Adhesive, 3 ... Wiring (electrocopper plating film), 4 ... Resist (plating resist) 5) Terminal plating, 6 ... Temporary substrate, 6 '... Metal substrate, 7 ... Conductive thin film, 8 ... Heating furnace, 9 ... Stripping roller, 10 ... Reinforcing conductor, 11 ... Wiring, 11A ... End of wiring , 12 ... Copper foil (conductive thin film), 12A ... Etching residue, 13 ... Resist (etching resist), 14 ... Adhesive, 15 ... Catalyst, 16 ... Electroless copper plating film, 16 '... Electromigration, 17 ... Electricity Copper plating film, CW: wiring width (conductor width), CS: wiring gap (conductor gap), CP: wiring pitch (conductor pitch), CT: wiring thickness (conductor thickness).

Claims (6)

In a method of manufacturing a wiring board that forms wiring on one surface of an insulating substrate,
Forming a conductive thin film on the surface of the temporary substrate corresponding to the insulating substrate ;
After forming a resist (plating resist) in the portion not forming a wiring on the conductive thin film, and forming a wiring of a predetermined pattern by electrolytic copper plating to the portion for forming the wiring on the conductive thin film,
A step of bonding the insulating substrate using an adhesive on the surface before Symbol wiring and the resist is formed of the temporary substrate,
Peeling the temporary substrate, transferring the wiring and the resist, and the conductive thin film to the insulating substrate;
And a step of removing the conductive thin film from the surface of the wiring and the resist . Before the step of peeling the temporary substrate,
Heat treatment is performed so that the adhesion or adhesion between the temporary substrate and the conductive thin film is lower than the adhesion between the insulating substrate and the adhesive and the adhesion between the wiring and the resist and the adhesive. The method for manufacturing a wiring board according to claim 1. Wherein the step of bonding the insulating substrate is bonded with a thermosetting resin as the adhesive,
The method for manufacturing a wiring board according to claim 2, wherein an adhesion force or an adhesive force between the temporary substrate and the conductive thin film is reduced by heating when the thermosetting resin is cured. Wherein the step of bonding the insulating substrate is bonded with the thermoplastic resin as the adhesive,
The wiring board according to claim 2, wherein the adhesive force or adhesive force between the temporary substrate and the conductive thin film is reduced by heating when the thermoplastic resin is softened and attached to the temporary substrate. Production method. As the temporary substrate, a tape-shaped insulating substrate that is long in one direction,
5. The wiring board according to claim 1, wherein each of the steps is performed in the middle of winding the tape-shaped insulating substrate wound around a reel onto another reel. Production method. A wiring board provided with wiring via an adhesive on one surface of an insulating substrate, and a plating resist provided between the wirings,
The wiring and the plating resist are prepared by transferring a material provided on a conductive thin film provided on the surface of a temporary substrate prepared separately from the insulating substrate to one surface of the insulating substrate via an adhesive. The
Wherein between the insulating substrate and the plating resist, the wiring board to which the same adhesive and adhesive interposed between the wiring and the insulating substrate is characterized that you have interposed.

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