JP2011243778A - Printed wiring board and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed wiring board which can suppress or avoid dimensional errors, shape distortion and deformation in flying leads placed to project into device holes, and a method manufacturing the same.SOLUTION: On the surface of an insulating base material 1 of the printed wiring board, there are wires 2 and a device hole 4, as well as flying leads 3 placed to connect with the wires 2 and to project into the device hole 4. The device hole 4 is composed of first device holes 5 (5a, 5b, 5c) formed to at least contain the ends of the flying leads 3, and a second device hole 6 which is larger than the first device holes 5 and formed to be continuous at least partially with the first device holes 5.

Description

  The present invention relates to, for example, a TAB (Tape Automated Bonding) type or TCP (Tape Carrier Package) type printed wiring board having a device hole and a flying lead provided so as to protrude from the device hole, and a method of manufacturing the printed wiring board.

  Among this type of printed wiring board and its manufacturing method, there are those called TAB method and TCP method (hereinafter collectively referred to as TAB) that existed before about 1990.

  FIG. 12 is a diagram showing a configuration of a main part of a conventional TAB type printed wiring board, FIG. 13 is an enlarged view of the vicinity of the tip of the flying lead, and FIG. 14 is a single tape substrate. It is a figure which shows an example of the conventional TAB type printed wiring board formed by arranging a plurality of rows of TABs.

  As shown in FIG. 12, a TAB type printed wiring board 111 having a structure having flying leads has a wiring 102 and flying leads 103 connected to the wiring 102 on the surface of an insulating film substrate 101 such as a polyimide resin film. It is provided by etching the copper foil.

  In such a printed wiring board, the vicinity 105 of the front end portion of the flying lead 103 is provided in a state of protruding into the region of the device hole 104 like a cantilever as shown in an enlarged view in FIG. . An IC (not shown) is mounted in the device hole 104 so that the connection pad of the IC and the flying lead 103 are connected.

  The wiring 102 is bonded to the surface of the insulating film substrate 101 via the adhesive layer 106, and the protective layer covers the almost entire surface of the insulating film substrate 101 including the surface thereof. A protective layer 110 is provided with an adhesive layer 109 for use. In FIG. 12, the adhesive layer 109 and the protective layer 110 are collectively illustrated as a cover lay 107 for the sake of simplicity of illustration. Sprocket holes 108 are arranged on both the left and right ends of the insulating film substrate 101 (Patent Document 1).

  Moreover, although illustration is abbreviate | omitted, what is called double-sided wiring TAB etc. of the structure which provided the wiring not only on the single side | surface of an insulating film base material but the front and back both surfaces are proposed (patent document 2).

  The main application of the printed wiring board having such a flying lead is generally for a module in which a liquid crystal driver IC is mounted from around 1990 to recent years. At present, COF (Chip On Film) is generally used for the liquid crystal driver IC module. However, in some cases, TAB type printed wiring boards having flying leads are still used.

  In general, TAB type printed wiring boards have a so-called industry-standard standard for the width dimension of a single carrier tape, and the width is improved by improving the optical system of a projection exposure machine or by advancement of photolithography technology. Dimensional standards have been expanded sequentially, such as 35 mm, 48 mm, and 70 mm.

  In addition to the TAB manufacturing process, a so-called roll-to-roll manufacturing method has generally been adopted not only for the process of mounting an IC chip on a TAB. In recent years, as a result of technological development related to the TAB manufacturing method, a projection exposure machine capable of handling a wide width exceeding 150 mm has been put into practical use. Therefore, as shown in FIG. It is also possible to arrange TABs 111-1, 111-2, and 111-3 with a width of 35 mm or 48 mm in multiple rows, such as three rows, and expect further improvements in production efficiency and manufacturing costs. It has come to be.

  In addition, the integration density of IC chips to be mounted is further increased, and the wiring pitch tends to be further miniaturized. In order to cope with this, the fine patterning technology for flying leads and wiring is further refined. There is a strong demand for realization.

  Along with this, device holes also tend to be large dimensions, such as 10 mm × 30 mm and 15 mm × 15 mm. Alternatively, even if each device hole is not so large, a plurality of device holes are provided, and a configuration in which the total area of the device holes becomes large has appeared.

Japanese Patent Application Laid-Open No. 06-5562 Japanese Patent Laid-Open No. 04-239739

  As described above, in the TAB type printed wiring board having flying leads, it is possible to improve production efficiency and manufacture while responding to further higher integration of IC chips and further refinement of wiring patterns required in connection with it. In order to achieve cost reduction, it has been required to form a plurality of rows of TABs in a single tape carrier. In addition, there is a growing demand for device holes to have large dimensions such as 10 mm × 30 mm and 15 mm × 15 mm, and to provide a plurality of device holes even if the individual dimensions are small.

  However, when such a large device hole or a plurality of device holes are provided, or when a plurality of rows of TABs are provided in a single tape carrier (in this case, a plurality of device holes are necessarily formed in the width direction). There is a problem that dimensional errors, shape distortion, deformation, etc. occur in the flying leads in the finished TAB type printed wiring board. These problems cannot be improved or eliminated even if further improvements are made to the optical system of the projection exposure apparatus and the photolithography technology. In addition, trials and measures to solve these problems have not yet been proposed, and sufficient studies have not been conducted from elucidating the causes of such flying lead shape defects. There wasn't.

  The present invention has been made in view of such problems, and its purpose is to suppress or eliminate the occurrence of dimensional errors, shape distortions and deformations in flying leads provided so as to protrude into device holes. It is to provide a wiring board and a manufacturing method thereof.

  The printed wiring board of the present invention is a printed wiring board having a wiring, a device hole, and a flying lead provided so as to protrude from the device hole while being connected to the wiring, on the surface of the insulating substrate. A protective layer is provided so as to cover the wiring, and the protective layer is formed so as to recede from the end face of the insulating base, and the end face of the protective layer and the insulating base It has the area | region which comes to align with an end surface in the same position, It is characterized by the above-mentioned.

  The method for producing a printed wiring board of the present invention is a printed wiring board including a step of providing wiring on a surface of an insulating substrate, a step of providing a device hole, a step of providing a flying lead, and a step of providing a protective layer. In the manufacturing method, the step of opening the first device hole so as to include at least a portion where the tip of the flying lead is provided on the insulating base material, and after opening the first device hole, A step of pasting a conductive foil on the surface of the insulating substrate, a step of patterning the conductive foil to form the wiring and the flying lead, and after forming the flying lead, the wiring A protective layer is provided thereon, a second device hole is opened so as to be continuous with the first device hole, and the second device hole and the first device hole are opened. The device comprises a step of forming a continuous device hole with a vice hole, wherein the protective layer is insulated from the end surface of the insulating base and the end surface of the protective layer. It has the area | region which comes to align with the end surface of a conductive base material, It is characterized by the above-mentioned.

  According to the present invention, it is possible to suppress or eliminate the occurrence of dimensional error, shape distortion, and deformation in the flying lead as the most important effect by the above-described means.

It is a figure which shows the structure of the principal part of the printed wiring board which concerns on embodiment of this invention. It is a figure which extracts and shows especially the part by which the 1st device hole was opened in the printed wiring board which concerns on embodiment of this invention, and its manufacturing method. It is a figure which extracts and shows especially the part by which the 2nd device hole is opened following the 1st device hole in the printed wiring board which concerns on embodiment of this invention, and its manufacturing method. It is a figure which extracts and shows especially the device hole finally formed by the manufacturing method of the printed wiring board concerning an embodiment of the invention. It is a figure which extracts and shows the variation of the 2nd device hole in the manufacturing method of the printed wiring board concerning embodiment of this invention especially about the part. In the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention, a variation of the coverlay pattern at the stage after the first device hole drilling and before the second device hole drilling is shown. It is a figure extracted and shown especially. It is a figure which extracts and shows especially the coverlay of the state after the 2nd device hole drilling in the printed wiring board which concerns on embodiment of this invention, and its manufacturing method. It is a figure which shows the flow of the main manufacturing processes in the manufacturing method of the printed wiring board which concerns on the Example of this invention. It is a figure which shows the state in which the 1st device hole was opened and the flying lead and wiring were formed in the printed wiring board which concerns on the Example of this invention, and its manufacturing method. It is a figure which shows the state of the stage after providing a coverlay and before opening a 2nd device hole in the printed wiring board which concerns on the Example of this invention, and its manufacturing method. It is a figure which shows the process of opening a 2nd device hole, after providing a coverlay in the printed wiring board which concerns on the Example of this invention, and its manufacturing method. It is a figure which shows the structure of the principal part of the conventional TAB system printed wiring board which has a general flying lead. FIG. 13 is an enlarged view showing the vicinity of the leading end of a flying lead in the printed wiring board shown in FIG. 12. It is a figure which shows the one aspect | mode of the conventional TAB system printed wiring board formed by arranging and forming a plurality of rows on one tape base material.

  Hereinafter, a printed wiring board and a manufacturing method thereof according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the printed wiring board according to the embodiment of the present invention includes a wiring 2, a flying lead 3 connected to the wiring 2, and the flying lead 3 on the surface of the insulating film substrate 1. A device hole 4 provided so as to protrude and a cover lay 7 for protecting the wiring 2 are provided.

  The device hole 4 includes a first device hole 5 (5a, 5b, 5c; hereinafter referred to as the first device hole 5a) as shown in FIG. 5b and 5c are collectively referred to as the first device hole 5), and a hatched line is shown in FIG. 3 provided so as to be continuous with the first device hole 5. And the second device hole 6 as described above. Here, in FIG. 2, FIG. 3, and FIG. 4, in order to simplify the illustration, only the first device hole 5, the second device hole 6, the flying lead 3 and the vicinity thereof are particularly extracted and drawn. Yes, the wiring 2 and the like are omitted.

  More specifically, as shown in FIG. 2, the first device holes 5 a, 5 b, and 5 c are openings with a small area that can include at least the tip of the flying lead 3 to the minimum necessary level. Are provided as independent and discontinuous openings. Referring to the example of FIG. 2, the first device hole 5a is provided so as to include the tips of all the flying leads 3 in the flying lead row 3a. The first device hole 5b is provided so as to include the tips of all the flying leads 3 in the flying lead row 3b. The first device hole 5c is provided so as to include the tips of all the flying leads 3 in the flying lead row 3c.

  Then, as shown in FIG. 3, the three non-continuous first device holes 5a, 5b, and 5c provided independently are arranged so that the second device hole 6 is continuous to all of them. By being provided, the openings are continuous and connected through the second device hole 6 (including the second device hole 6). That is, the first device holes 5a, 5b, and 5c and the second device hole 6 constitute a continuous device hole 4 having a large area as shown in FIG.

  Here, more specifically, “at least the front end portion of the flying lead 3” means a portion used for electrical connection in the flying lead 3, that is, the printed wiring board (TAB). Of course, this means a portion that is joined to a connection pad or the like provided on an IC chip or other semiconductor chip to ensure electrical connection.

  The method for manufacturing a printed wiring board according to the embodiment of the present invention includes an insulating film substrate 1 that includes at least a portion where each flying lead 3 of each flying lead row 3a, 3b, 3c is provided. In addition, after opening the first device holes 5a, 5b, and 5c, and opening the first device holes 5, the surface of the insulating film substrate 1 is almost entirely on the first device hole 5. A step of pasting a conductor foil such as a copper foil, including a region, a step of patterning the conductor foil to form the wiring 2 and the flying lead 3, The second device hole 6 is opened so as to be continuous with respect to all the device holes 5 (5a, 5b, 5c), and the second device hole 6 and the first device hole 5a, 5b, and forming a single monolithic device hole 4 formed continuously and 5c, comprises a flow of the main process.

  More specifically, as shown in the flow of the main steps in FIG. 8, first, an adhesive layer is pasted on the surface of the insulating film substrate 1 (Step-1; S1 in FIG. 8). Notation (the same notation is used for the following steps).

  Subsequently, a first device hole 5 is formed (S2). This process can be performed by, for example, a so-called punching method by press working using a mold, a so-called laser cutting method by, for example, laser irradiation, or the like.

  A copper foil is affixed to almost the entire surface of the insulating film substrate 1 including the region of the first device hole 5 (S3).

  Then, a photoresist is applied on the copper foil by a series of photolithography processes, and patterning such as wiring 2 and flying leads 3 is exposed to developed on the photoresist (S4).

  Subsequently, a so-called backing is applied to the portion of the first device hole 5 on the back surface of the printed wiring board (S5).

  At this time, since the first device hole 5 has only a small area corresponding to the necessary minimum region including at least the tip portion of the flying lead 3, the backing material necessary for backing is As compared with the conventional case where a device hole having a large area is backed, the amount of use can be significantly reduced.

  After backing, the copper foil is patterned by, for example, an etching method to form the wiring 2 and the flying lead 3 (S6).

  At this time, since the first device hole 5 has only a small area corresponding to the necessary minimum region including at least the tip portion of the flying lead 3, the first device hole having such a small area is used. The copper foil on the opening region of the device hole 5 has an expansion and contraction caused by heat, moisture, and various other disturbance factors as compared with the case where the copper foil is provided on the opening region of the device hole having a large area. Distortion and the like are remarkably small. As a result, the dimensional error of the flying lead 3 formed by patterning the copper foil on the opening region of the first device hole 5, various defects such as shape distortion and deformation are generated. It will be suppressed or eliminated.

  After forming the wiring 2 and the flying lead 3, the backing material is removed (S7). Further, the photoresist is peeled off (S8).

  Subsequently, the cover lay 7 (solder resist is also possible so as to cover almost the entire surface of the insulating film substrate 1 including the top of the wiring 2 except for the surface of the flying lead 3 and connection terminals (not shown). ) Is provided (S9).

  Subsequently, plating such as gold (Au) plating is performed on the surface of the flying lead 3 that is not covered with the cover lay 7 and is exposed, and various other connection terminal portions (S10).

  Then, a second device hole 6 is provided (S11).

  By providing the second device hole 6, a continuous device hole 4 is formed in which the second device hole 6 and the first device holes 5a, 5b, and 5c are continuously formed.

  Here, it is desirable from the viewpoint of improving the production efficiency that all the steps described above are performed consistently on a production line corresponding to a so-called roll-to-roll method of 10 m winding or more. However, it is needless to say that the present invention is not limited to this.

  As described above, in the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention, insulation is performed before the step of forming the wiring 2 and the flying lead 3 by bonding the conductive foil to the insulating film substrate 1. 2 is provided with small first device holes 5a, 5b and 5c as shown in FIG. 2, and the copper foil on the region of the first device hole 5 is provided. After forming the flying lead 3 by patterning such a conductor foil, the first device holes 5a, 5b, and 5c that are individually formed in a discontinuous manner are formed by drilling and providing the second device holes 6. The device hole 4 is formed by the first device holes 5 a, 5 b, 5 c and the second device hole 6. Therefore, in the step of forming the flying lead 3, the copper foil to be the flying lead 3 is on the opening region of the first device hole 5 having a small area as small as necessary. As a result, it is possible to suppress or eliminate the occurrence of dimensional errors, shape distortion, deformation, and the like in the finished flying lead 3.

  Further, since the amount of so-called backing material used to close the device hole from the back surface during patterning of the flying lead using the etching process can be reduced, the back surface as in the case of the prior art can be achieved. Adverse effects such as increase in material cost due to increased use of stoppers, and increase in application area of backing materials, such as residual resin residue and sludge It is possible to avoid or eliminate various problems such as adhering to the TAB (printed wiring board) of the product and the manufacturing apparatus.

  The inventors of the present invention have tried various experiments and considerations on the cause of problems such as defective pattern formation of flying leads in printed wiring according to the prior art. And the main cause of that is that the flying leads were formed by patterning the conductor foil in a state of floating in the air on the opening area of the large device hole. The inventor came up with the present invention.

  That is, in the conventional technique, the conductive foil of the portion that is patterned and becomes the flying lead is, for example, on the opening area of the device hole having a large area such as 15 mm × 15 mm from below by the insulating film substrate 1 or the like. There was no support or adhesion. For this reason, the conductor foil on the opening region of the device hole is likely to be bent in the normal direction to the surface (that is, the device hole penetrating direction).

  Moreover, in the manufacturing process of a printed wiring board, in the part in which the device hole was provided, the insulating film base material does not exist but only conductor foil exists. On the other hand, in a portion where no device hole is provided, the conductor foil and the insulating film base material are bonded together, so to speak, it exists as a composite material. For this reason, the portion of the conductor foil where the device hole exists, that is, the portion of the conductor foil where the flying lead is formed, is subject to expansion and contraction corresponding to heat, humidity, etc. in the conductor foil alone. On the other hand, the conductive foil in the part where the device hole does not exist, that is, the conductive foil in the part where the wiring is mainly formed, causes expansion and contraction as a composite material of the conductive foil and the insulating film substrate. .

  For this reason, the larger the number of device holes and the greater the number of device holes, the greater the difference in the amount of expansion and contraction of the conductor foil per full width of the printed wiring board between the part where the device hole is provided and the other part. Therefore, if the conductor foil that stores the strain stress caused by such a large difference in expansion and contraction is subjected to pattern processing to form flying leads and wiring, the resulting flying leads are ignored. An unacceptable pitch shift, dimensional error, distortion or deformation will occur.

  And generation | occurrence | production of the above bending, distortion, etc. of conductor foil exists in the tendency which becomes more remarkable as a device hole becomes large.

  Due to such factors, in the conventional printed wiring board, as the device hole becomes larger, a dimensional error, a shape distortion, a deformation, and the like occur in the flying lead.

  Therefore, in the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention, until the flying lead 3 is completed by patterning the conductive foil such as copper foil by an etching method or the like. By stopping the formation of the first device hole 5 having at least a necessary minimum area including at least the vicinity of the tip portion, the opening area of the first device hole 5 having the small area is stopped. The flying lead 3 was formed by patterning the conductor foil having a small area existing above.

  Thus, by making the first device hole 5 an opening having a small area, the area of the conductive foil existing in a state of floating in the air on the opening region can be reduced, and as a result, It is possible to suppress or eliminate the occurrence of bending or distortion in the conductor foil for forming the flying lead 3.

  Then, by opening and opening the remaining portion, that is, the second device hole 6, the device hole 4 having a large area is finally obtained by the sum of the first device hole 5 and the second device hole 6. Can be obtained.

  In addition, by using the first device hole 5 as an opening having a small area in this way, it is possible to reduce the amount of the backing material used as a secondary effect.

  That is, in the conventional technique, when the area of one device hole is large, or when a plurality of device holes are provided and the total area of the device holes is large, the back of the device hole filled from the back side is filled. The application / filling amount of an etching resistant resin material generally used as a stopper is increased, which increases the material cost. In addition, due to the increase in the amount of use, the load of the processing liquid and filter used when removing the backing material increases, and in some cases, the residue of the backing material, sludge, etc. in the product There has also been a problem that it remains on the surface of a certain printed wiring board or a manufacturing apparatus.

  However, according to the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention, the first device hole 5 to be backed includes at least the vicinity of the tip of the flying lead 3 as described above. Since it has only a small area of the necessary minimum, it is possible to significantly reduce the amount of backing material used compared to the case of the prior art, and as a result, the material cost is reduced. It is possible to achieve a reduction in price and suppression or elimination of residues such as residues and sludge. In addition, the quality of the printed wiring board as a product can be stabilized, and the total manufacturing cost can be further reduced, including the costs related to the processing liquid for the backing material and filters. Become.

  In view of the above effects, the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention are large openings in which at least one side is 10 mm or more out of two orthogonal sides of the device hole. It is particularly suitable for the case.

  As the protective layer, it is preferable to use a film containing any one of polyimide, polyamideimide, and aramid resin. The thickness of the protective layer is preferably 4 μm or more and 25 μm or less.

  As the insulating base material, it is preferable to use a film containing any one of polyimide, polyamideimide, and aramid resin. Moreover, it is preferable that the thickness of an insulating base material is 4 micrometers-125 micrometers.

  After providing a plurality of first device holes, a second device hole is opened, and a plurality of first device holes are continuously formed by the second device hole to form a continuous device hole. It is particularly preferred.

  In addition, although illustration is abbreviate | omitted, when patterning a conductor foil, the front-end | tip of several flying leads 3 is made into the pattern connected to the electric power feeding pattern for electrolytic plating, and the surface of all the flying leads 3 by the electrolytic plating method After plating, the leading ends of all the flying leads 3 are separated from the electrolytic plating power supply pattern and the electrolytic plating power supply pattern is removed from the printed wiring board as a product. You may make it remove.

  By doing so, it is not necessary to connect a power supply line for electrolytic plating to the other end of the flying lead 3, that is, the end of the wiring 2 connected to the flying lead 3.

  As a result, the degree of freedom in pattern design of the wiring 2 is increased, and for example, it is possible to form a pattern that cannot be substantially plated unless electrolytic plating is performed. In addition, the step of separating the leading end of the flying lead 3 from the electrolytic plating power supply pattern is completely used in the step of drilling the second device hole 6, so that it is not necessary to increase the number of steps. There are also benefits.

  In addition to the power supply line, the support pattern has no meaning in terms of electrical circuit, but is connected to the tips of all flying leads 3 and mechanically supports the tips of all of the flying leads 3. As the second device hole 6 is drilled, the support pattern may be separated from the tips of all flying leads 3 and removed from the printed wiring board as a product.

  By doing so, the flying lead 3 is deformed or distorted between the formation of the flying lead 3 and the formation of the second device hole 6. By supporting it, it becomes possible to suppress or eliminate it.

  Further, when the second device hole 6 is drilled, some errors and deviations are inevitably generated in the positions and dimensions. If such a dimensional error or positional deviation is larger than the required accuracy, the second device hole is significantly greater than at least one of the plurality of first device holes 5. There is also a risk (risk) that 6 will not be in a continuous state.

  Therefore, in order to overcome such a concern, as shown in FIG. 5, the outer dimension of the second device hole is slightly larger than the theoretical dimension without excess or deficiency as shown in FIG. Setting to is effective. More specifically, it is desirable to have a larger external dimension in consideration of a dimensional error, an amount of positional deviation and a predetermined safety factor that are expected to occur when the second device hole 6 is formed. .

  In this case, the planar shape of the completed device hole 4 is not strictly a regular rectangular shape as shown in FIG. 1, but each side has a minute crank as shown in FIG. However, there is no particular inconvenience or the like. Even if the outer dimensions are not so large, in practice, some errors and deviations are inevitably generated in the position and dimensions of the second device hole 6 as described above. Strictly speaking, the planar shape of the completed device hole 4 is not a regular rectangle such as a regular rectangle, but also a shape including a minute crank shape. .

  A printed wiring board as described in the above embodiment was produced. In the following explanation, the names of manufacturers and product names of various materials used are abbreviated names.

  First, as an insulating film substrate 1, a polyimide film of Kapton (manufactured by Toray DuPont) and Upilex (manufactured by Ube Industries) is used, and an adhesive layer (not shown) is formed on the surface of the insulating film substrate 1. They were pasted together (S1 in FIG. 8; hereinafter simply expressed as S1).

  As an adhesive layer for TAB, for example, there are those supplied by manufacturers such as Toray and Yodogawa Paper Mill, and an appropriate one was selected according to the application of this embodiment. Here, in general, the adhesive manufacturer laminates the adhesive layer on the surface of the insulating film substrate 1, and at that time, the width and thickness of the film of the insulating film substrate 1 and the width of the adhesive layer・ Thickness will also be specified. The thickness of the film is generally 12 to 75 μm, and the thickness of the adhesive layer is generally 8 to 15 μm. The material of the film can be selected from those having a main component of resin such as PET (Polyethylene terephthalate), PEN (Polyethylene naphthalate), PPS (Polyphenylene sulfide), PAI (Polyamide-imide), and aramid.

  Subsequently, the first device hole 5 and the sprocket hole 8 were formed in the insulating film substrate 1 (S2).

  As the drilling process (opening process) of these through holes, a press working method using a die (so-called press punching method) is generally used. In addition, for example, a pinnacle blade (Thomson blade or engraving blade) Etc.), a laser cutting method, an etching method using chemicals, or the like can also be used.

  After the first device hole 5 was provided, a copper foil was bonded to almost the entire surface of the insulating film substrate 1 through the adhesive layer (S3).

  Then, after the lamination of the copper foil was completed, the adhesive layer was cured under the process condition settings suitable for the conditions specified by the adhesive manufacturer.

  As the laminated copper foil, either a rolled copper foil or an electrolytic copper foil can be used. It is desirable to use the back surface subjected to corrosion prevention treatment or roughening treatment.

  In addition to the copper foil, it is possible to use various metals and alloys having good conductivity that can be subjected to patterning or plating by an etching method.

  As a general method, the laminating process was performed by using a roll laminator and setting process conditions suitable for the conditions specified by the adhesive manufacturer. At that time, it is desirable to laminate in one step in order to keep the heat history to the adhesive layer constant regardless of whether it is a single or multiple.

  In addition to the general laminating method, for example, a double belt press method, a reduced pressure press method, or a method using a reduced pressure roll laminator can be selected as the copper foil laminating step. Alternatively, a copper foil (copper layer) may be formed on the surface of the insulating film substrate 1 by a casting method, a sputtering method, a vapor deposition method, a wet plating method, or the like.

  Subsequently, a photoresist is applied to the entire surface of the copper foil laminated on the surface of the insulating film substrate 1, the pattern of the wiring 2 and the flying lead 3 is projected and exposed by a projection exposure machine, and the latent image is obtained. Development was performed to obtain a photoresist pattern (S4).

  The photoresist may be negative or positive. In addition, a dry film can be used instead of the liquid photoresist.

  In addition to the projection exposure method, a proximity exposure method, a contact exposure method, or the like can be selected as the exposure method. Alternatively, a so-called direct drawing method using a laser beam or the like can be employed.

  Regarding these various working conditions and settings, the manufacturers of photoresists and dry films used in this process generally provide recommended conditions, so various conditions should be prepared to meet them. Is desirable. However, it goes without saying that the original working conditions are not denied.

  Subsequently, so-called backing was performed (S5).

  In the portion where the first device hole 5 is opened, the insulating film substrate 1 does not exist on the back surface of the copper foil. Therefore, in this part, the back surface of the copper foil is exposed unprotected. For this reason, if the copper foil is etched as it is to form the wiring 2 and the flying lead 3, the exposed back surface of the copper foil is dissolved by the etching solution. In order to prevent this, the first device hole is sealed with a backing material. As a specific method of backing, brushing is generally used, but other methods such as potting are also possible. Since there is a commercially available backing resin manufactured by NATCO, it was used in this example.

  After backing, the copper foil was subjected to pattern processing by an etching method to form the wiring 2 and the flying lead 3 (S6).

  As an etching solution, it is common to use an etching solution of ferric chloride or cupric chloride.

  In this way, as shown in FIG. 9, the wiring 2 and the flying lead 3 were formed on the surface of the insulating film substrate 1.

  Subsequently, removal of the backing material (S7) and stripping of the photoresist (S8) were performed.

  These processes use an alkaline solution such as sodium hydroxide to swell and dissolve the backing material and photoresist that are no longer needed, and also use the fluid power of the alkaline solution shower. Then, the backing material and the photoresist are removed chemically and physically. The various conditions for these two steps are generally set by the manufacturer of the selected backing material or photoresist, so that the conditions are set accordingly.

  Subsequently, a cover lay 7 (solder resist is also acceptable) of the wiring 2 is provided in a shape as shown in FIG. 7 by extracting only the cover lay 7 (S9).

  When a solder resist was used instead of the coverlay 7, the material was purchased in ink. Then, it was printed and formed into a predetermined shape as shown in FIG. 7 by a screen printing method. The ink manufacturers include Hitachi Chemical, Nippon Polytech, Ajinomoto Finetech, and Asahi Chemical Research Laboratories. In addition, when a more accurate opening is required, it is desirable to select a photosensitive solder resist. A representative manufacturer is solar ink manufacturing.

  The cover lay 7 can be made of a material that can be produced independently with the insulating film substrate 1 (resin film such as PI, PET, PAI, or aramid) or an adhesive layer, or a commercially available cover lay. Materials may also be used.

  As manufacturers of such coverlays 7, there are Toray, Arisawa Seisakusho, Nikkan Kogyo, etc. In the case of the cover lay 7, it is common to position the object processed into the required shape, attach it to the wiring board, and pressurize and heat. And Ishii notation. For pressurization and heating, there are an atmospheric pressure press and a laminator, a vacuum press and a vacuum laminator. Regarding the working conditions, there are recommended conditions for each selected coverlay 7, so that it may be referred to.

  A state in which the coverlay 7 is formed in this way is shown in FIG. In this state, in the opening of the cover lay 7, the insulating film base material 1 still remains in a T shape at the center thereof, and this portion exists, so that the first device hole is present. 5a, 5b, and 5c exist as openings that are isolated from each other.

  Subsequently, in order to increase the connection reliability on the exposed portion of the flying lead 3 that is not covered by the cover lay 7, that is, on the surface of the connection terminal or the like (not shown), gold Plating such as (Au) plating was performed (S10).

  This plating may be electrolytic plating or electroless plating. Further, this plating may be formed on the entire surface of the wiring pattern before providing the coverlay 7 or the solder resist.

  Then, the second device hole 6 was formed in a position (shape) as shown by hatching in FIG. 11 (S11). In other words, since the first device holes 5a, 5b, and 5c are openings that are isolated from each other because they have remained in the T shape, the second device hole 6 is provided. And completely removed.

  By providing the second device hole 6, there is no interruption as shown in FIG. 12 (that is, the first device holes 5a, 5b, and 5c and the second device hole 6 are continuous). A single large device hole 4 was formed.

  As a method for opening the second device hole 6 (a method for forming an opening), as in the case of the first device hole 5, a press working method using a mold (so-called press punching method) is generally used. In addition, for example, a push-cut method using a pinnacle blade (including a Thomson blade or an engraving blade), a laser cutting method, an etching method using a chemical, or the like can also be used.

  Here, the opening (drilling) of the second device hole 6 may be performed twice or more. In that case, in the second and subsequent opening shapes, in particular, the portion that overlaps (intersects) with the already opened opening is as perpendicular as possible from the viewpoint of avoiding the occurrence of burrs in that portion. It is desirable to cross.

  The second device hole 6 can be formed at a stage prior to the plating process described as S10.

  The opening pattern of the coverlay 7 may be as shown in FIG.

  That is, the opening of the cover lay 7 includes a large area including a region corresponding to the second device hole 6 (shown as a region 9d in FIG. 7) as shown in FIG. 6, the mechanical rigidity of the entire printed wiring board including the cover lay 7 and the insulating film substrate 1 is the first as shown in FIG. Compared to the case where only the openings 9a, 9b and 9c corresponding to the device holes 5a, 5b and 5c have a minimum required area (that is, the region 9d is not an opening). There is a risk of lowering.

  Therefore, from this point of view, the coverlay 7 has openings 9a, 9b, 9c corresponding to the first device holes 5a, 5b, 5c, respectively, but portions corresponding to the second device holes 6 (that is, regions) For 9d), an opening is not intentionally provided, and a pattern in which the cover lay 7 is present is provided in that portion. Finally, when the second device hole 6 is drilled, the second device It is more desirable to remove the coverlay 7 in the region 9d together with the punching of the insulating film substrate 1 in the hole 6 portion.

  According to the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention as described above, it is possible to suppress or eliminate the occurrence of dimensional error, shape distortion, and deformation in the flying lead.

  In addition, as a secondary effect, it is possible to reduce the amount of so-called backing material used to close the device hole from the back surface during flying lead patterning using an etching process. Resin residue and sludge, etc. of the backing material generated due to the increased use of the stopping material and the increased application area, for example, the printed wiring board (TAB) of the product and the manufacturing apparatus Various problems such as adhering to the surface could be avoided or eliminated.

  In addition, the cover lay 7 is generally formed around the device hole 4 in a state where the end face of the cover lay 7 is retracted from the end face of the insulating film substrate 1. When the IC chip is sealed with a sealing material, the insulating film base material in an overhanged state without being covered with the cover lay 7 There is a possibility that voids may be generated by trapping bubbles in a portion such as a step formed by the vicinity of the end face of 1.

  However, according to the printed wiring board and the manufacturing method thereof according to the embodiment of the present invention, the end face of the cover lay 7 and the end face of the insulating film substrate 1 are the same as the second device hole 6 is drilled. Since the number of regions that are aligned with each other will be larger than in the case of the prior art, it is possible to reduce or eliminate the risk of voids occurring by enclosing air bubbles when sealing the IC chip. became.

  In the above-described embodiments and examples, when a plurality of first device holes 5 are provided, such as three first device holes 5a, 5b, and 5c, that is, flying lead rows 3a, 3b, and 3c. As described above, the case where the present invention is applied to the printed wiring board having a plurality of flying leads 3 is described. However, the case where there is one first device hole 5, that is, the case where there is only one flying lead row. Of course, the present invention is applicable.

  Further, the present invention is particularly suitable for a printed wiring board having a structure such as TAB having an insulating film substrate made of a highly flexible material such as polyimide resin. In the embodiments and examples, the case where the present invention is applied to a printed wiring board having such an insulating film substrate has been described, but instead of the insulating film substrate, a glass epoxy group which is a so-called rigid substrate material. Needless to say, the present invention can also be applied to a printed wiring board having a structure using a material and having a device hole and a flying lead provided so as to protrude therefrom.

DESCRIPTION OF SYMBOLS 1 Insulating film base material 2 Wiring 3 Flying lead 4 Device hole 5 1st device hole 6 2nd device hole 7 Coverlay 8 Sprocket holes 9a, 9b, 9c Opening 9d corresponding to the 1st device hole in a coverlay Region 10 corresponding to the second device hole in the coverlay Entire opening corresponding to the device hole in the coverlay

Claims (8)

A printed wiring board having a wiring, a device hole, and a flying lead provided so as to protrude from the device hole while being connected to the wiring on the surface of the insulating substrate,
A protective layer is provided so as to cover the wiring, and the protective layer is formed so as to recede from the end face of the insulating base, and the end face of the protective layer and the end face of the insulating base And a printed wiring board characterized by having a region in which they are aligned at the same position. The printed wiring board according to claim 1,
The device hole is a printed wiring board, wherein at least one of the two orthogonal sides is 10 mm or more. In the printed wiring board according to claim 1 or 2,
The printed wiring board, wherein the protective layer is made of a film containing any resin of polyimide, polyamideimide, and aramid. In the printed wiring board in any one of Claim 1 thru | or 3,
The printed wiring board, wherein the insulating substrate is made of a film containing any one of polyimide, polyamideimide, and aramid resin. The printed wiring board according to any one of claims 1 to 4,
The printed wiring board, wherein the insulating substrate has a thickness of 4 μm to 125 μm. In the printed wiring board in any one of Claim 1 thru | or 5,
The printed wiring board, wherein the protective layer has a thickness of 4 μm or more and 25 μm or less. A method of manufacturing a printed wiring board including a step of providing wiring on a surface of an insulating substrate, a step of providing a device hole, a step of providing a flying lead, and a step of providing a protective layer,
Opening the first device hole in the insulating base material so as to include at least a portion where the tip of the flying lead is provided;
After opening the first device hole, attaching a conductive foil to the surface of the insulating substrate;
Applying pattern processing to the conductor foil to form the wiring and the flying lead;
After forming the flying lead, a protective layer is provided on the wiring, a second device hole is opened so as to be continuous with the first device hole, and the second device hole and the first device hole are formed. Consisting of a process of forming a continuous device hole,
The protective layer has a region formed so as to recede from the end surface of the insulating base material, and a region where the end surface of the protective layer and the end surface of the insulating base material are aligned at the same position. A method for producing a printed wiring board. In the manufacturing method of the printed wiring board according to claim 7,
The plurality of first device holes are provided, and then the second device hole is opened, so that the plurality of first device holes are continuously connected by the second device hole, and the devices are connected to each other. A method of manufacturing a printed wiring board, wherein holes are formed.

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