JP2019075485A - Film substrate, and method for manufacturing film substrate - Google Patents

Abstract

To provide a film substrate that has an adhesive layer filled with an inorganic filler in a more appropriate state, and a method for manufacturing the same.SOLUTION: A metal foil layer 10 on which a wiring pattern for a wiring circuit is formed and an organic insulating film 20 are adhered to each other with an adhesive layer 201 filled with an inorganic filler 30, such as silica. The adhesive layer 201 is filled with the inorganic filler 30 at a predetermined interval in a regular arrangement, for example, in a state where the inorganic filler is arranged in a geometric shape, such as a lattice state or a honeycomb shape. This makes it possible to make the strength in the adhesive layer 201 uniform. The adhesive layer 201 can be filled with the inorganic filler 30 in the regular arrangement over the entire area, but as illustrated in FIG. 2, the adhesive layer may be divided into specific areas 301, 302 and a non-specific area 303 according to a wiring circuit formed on the metal foil layer 10 such that the specific areas are filled with the inorganic filler 30 and the non-specific area is not filled with the inorganic filler.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a film substrate and a method of manufacturing a film substrate, and, for example, to a technique used in a wiring substrate and a power supply circuit substrate and in which a conductive pattern metal layer is formed on an insulating layer resin.

BACKGROUND In recent years, flexible printed wiring boards (FPCs) on which electronic components are mounted are widely used in various electronic devices such as mobile phones and digital cameras.
Then, with the progress of high integration of semiconductor devices, an FCB (Flip Chip Bonding) mounting method has been developed and put to practical use in order to cope with the increase in device density.
In this FCB mounting method, there are, for example, TAB (Tape Automated Bonding) technology and COF (Chip on Film) technology as a method of efficiently enabling mass production. These use a film substrate in which a conductor metal is adhered with an adhesive (adhesive layer) on an insulating film of a predetermined width, and the conductor metal of the film substrate is formed into a desired lead pattern shape by a method such as etching It is.
In such a film substrate, a technique for improving chemical resistance and heat resistance has been proposed by filling the adhesive layer with an inorganic filler (Patent Document 1).

However, in the conventional film substrate, in order to improve chemical resistance etc., the inorganic filler is filled at a predetermined volume density over the entire region of the film substrate.
That is, since the adhesive in which the inorganic filler is mixed in advance at a constant volume ratio or weight ratio is applied to the whole of the film substrate, the density of the packing density, ie, a high density area and a low density area And caused a difference in flexibility depending on the area.
In addition, in the film substrate, there is a region where high flexibility is required and a region where it is not so, but in the conventional film substrate, the region where flexibility is required may become a high density region .
Furthermore, since the inorganic filler was filled over the entire area of the adhesive layer, the amount of filler used was increased.
As described above, in the conventional film substrate, the adhesive layer is not necessarily filled in an appropriate state.

Japanese Examined Patent Publication 7-114221

  An object of the present invention is to provide a film substrate in which an inorganic filler is filled in an adhesive layer in a more appropriate state, and a method of manufacturing the same.

(1) The invention according to claim 1 comprises a metal foil layer on which a wiring pattern for a wiring circuit is formed, an insulating film, and an adhesive layer for bonding the metal foil layer and the insulating film. The adhesive layer provides a film substrate characterized in that the inorganic filler is filled in a regular arrangement.
(2) In the invention according to claim 2, the adhesive layer is characterized in that the inorganic filler is arranged in a geometric lattice pattern, the film substrate according to claim 1 Do.
(3) In the invention according to claim 3, the film according to claim 1 or 2, wherein the adhesive layer is filled with the inorganic filler in a specific region. Provide a substrate.
(4) In the invention according to claim 4, the adhesive layer is filled with the inorganic filler at a different filling density in accordance with the specific region. Provide a film substrate.
(5) In the invention according to claim 5, the film according to claim 3 or 4, wherein the specific region is determined in accordance with a wiring pattern formed on the metal foil layer. Provide a substrate.
(6) In the invention according to claim 6, the insulating film is formed with an IC hole, and the adhesive layer is characterized in that at least a peripheral region of the IC hole is filled with the inorganic filler. The film substrate according to claim 1, claim 2 or claim 3 is provided.
(7) In the invention according to claim 7, the adhesive layer is a thermal effect adhesive layer, and any one of claims 1 to 6 is characterized in that The film substrate as described is provided.
(8) The invention according to claim 8 comprises a metal foil layer on which a wiring pattern for a wiring circuit is formed, an insulating film, and an adhesive layer for bonding the metal foil layer and the insulating film. The adhesive layer provides a film substrate having a specific region filled with an inorganic filler and a non-specific region not filled with an inorganic filler.
(9) In the invention according to claim 9, the preparing step of preparing the insulating film in which the thermosetting adhesive layer is formed on one surface, the inorganic filler on the upper surface of the adhesive layer, In the arrangement and / or the specific region, the step of arranging the inorganic filler and the metal foil layer on which the wiring pattern for the wiring circuit is formed on the upper surface of the inorganic filler arranged In the metal foil layer disposing step, the inorganic filler disposed on the upper surface is filled in the adhesive layer by heating the adhesive layer, and the adhesion is made to adhere the insulating film and the metal foil layer. And providing a process for producing a film substrate.

According to the invention as set forth in claims 1 to 7, since the inorganic filler is filled in a regular arrangement in the adhesive layer, the strength in the region filled with the inorganic filler is reduced. It can be made uniform.
According to the invention as set forth in claims 3 to 5 and claim 8, the inorganic filling in a more appropriate state is achieved by the specific area filled with the inorganic filler and the non-specific area not filled with the inorganic filler. It can be filled with an agent.

It is sectional drawing showing the structure of the film board | substrate in this embodiment. It is explanatory drawing about the specific area which fills an adhesive bond layer with an inorganic filler, and the non-specific area which is not filled. It is explanatory drawing showing the state in the manufacturing process of a film board | substrate. It is another explanatory view showing the state in the manufacturing process of a film substrate. It is explanatory drawing about the manufacturing process of the wiring board using a film board | substrate. It is another explanatory view about a manufacturing process of a wiring board using a film board. It is explanatory drawing showing the modification about the specific area | region which the inorganic filler fills, and the non specific area which is not filled.

Hereinafter, preferred embodiments of the film substrate of the present invention and the method for producing the same will be described.
(1) Outline of Embodiment In the film substrate 1 of the present embodiment, as shown in FIG. 1, the metal foil layer 10 on which the wiring pattern for the wiring circuit is formed, and the organic insulating film 20 are inorganic such as silica. It is adhered by an adhesive layer 201 filled with a filler 30.
In the adhesive layer 201, the inorganic fillers 30 (individual particles) are filled at regular intervals, for example, in a state of being arranged in a regular arrangement, for example, in a geometric shape such as a lattice shape or a honeycomb shape. Thereby, the strength in the adhesive layer 201, that is, the flexibility of the film substrate 1 can be made uniform.

Although it is possible to fill the entire region of the adhesive layer 201 in a regular arrangement, the inorganic filler 30 may be filled according to the wiring circuit formed on the metal foil layer 10 as shown in FIG. The region 301, 302 and the non-specific region 303 may be divided, and the specific region may be filled with the inorganic filler 30, and the non-specific region may not be filled.
The inorganic fillers 30 in the specific area are packed in a regular arrangement as shown in FIG. 1, but may not necessarily be regular.
As described above, by dividing into the specific areas 301 and 302 in which the inorganic filler 30 is filled and the nonspecific areas 303 in which the inorganic filler 30 is not filled, for example, it is more appropriate to set the area requiring high flexibility as the nonspecific area. The adhesive layer 201 can be filled in this state.
Furthermore, according to the necessity, the specific region may be filled with the specific region 301 filled with the inorganic filler 30 such as the peripheral region of the IC hole 203 at a higher density, and the inorganic filler such as the peripheral region to which the element is soldered. The agent 30 is divided into specific areas 302 which are filled at low density.
The specific region is determined according to the wiring pattern formed on the metal foil layer 10.

  In addition, according to the film substrate 1, the filler is regularly and / or filled in the necessary specific area, so that the organic insulating film is provided over the entire film substrate 1 and / or for the specific area. It is possible to suppress 20 moisture absorption and expansion and contraction due to temperature change.

(2) Details of the Embodiment FIG. 1 is a partial cross-sectional view showing the configuration of the film substrate 1 to which the present embodiment is applied, and the adhesive layer 201 is filled with the inorganic filler 30 in a grid shape as a regular array. Represents the state of
FIG. 1 (a) represents a side cross section along the grid of the grid arrangement, and (b) represents a cross section along a plane. What (b) represents the AA cross section in FIG. 1 (a) is (a) what represents the BB cross section in FIG. 1 (b).

The film substrate 1 is formed, for example, in a long size on the assumption that the film substrate 1 is wound around a reel having a diameter of about 20 to 40 cm.
The width of the film substrate 1 is, for example, the same standard as a 35 mm film for photographing, and is formed in a long shape of a full width W = 34.975 mm. Moreover, it forms in various sizes, such as 48 mm and 70 mm, as width according to the product used as object.
The film substrate 1 is a substrate used for TAB or COF, and the metal foil layer 10 is formed into a desired lead pattern shape by a method such as etching, laser processing, precision molding, etc. as described later.

As shown to Fig.1 (a), the film substrate 1 adhere | attaches the metal foil layer 10 in which the wiring pattern for wiring circuits is formed, the insulating film 20, and the metal foil layer 10 and the organic insulating film 20 to adhere | attach. The agent layer 201 is provided.
In the adhesive layer 201 of the present embodiment, the inorganic filler 30 for suppressing expansion and contraction due to moisture absorption or temperature change of the organic insulating film 20 is filled in a regular arrangement.

Although the metal foil layer 10 of this embodiment is comprised with copper foil, as long as it is normally used for board | substrate material as another metal, the kind in particular is not limited. For example, as the metal foil layer 10, a plate or foil of silver, platinum, gold, aluminum, nickel or the like can be used.
The thickness of the metal foil layer 10 is in the range of 3 to 75 μm. Preferably, it is in the range of 6 to 25 μm, and particularly preferably in the range of 12 to 18 μm. In the film substrate 1 of the present embodiment, the purpose is to manufacture a flexible substrate applicable as a multipurpose substrate. For example, in order to be usable as a substrate for a leaf spring switch besides a wiring substrate, the thickness is within the above range. Needed. Further, in order to secure the flexibility of the entire substrate required at the time of manufacture, the above setting range is adopted.

The organic insulating film 20 of this embodiment uses PI (polyimide) as an organic insulating film, but in addition, polyester, polyamide imide, liquid crystal polymer, polyether imide, polyphenylene sulfide, polyether ether ketone, etc. Insulating film, an inexpensive film such as PET or PEN, or an organic insulating film composed of a composite heat-resistant film such as epoxy resin-glass cloth or epoxy resin-polyimide-glass cloth may be used.
The thickness of the organic insulating film 20 is in the range of 3 to 75 μm. However, the thickness of the organic insulating film 20 of the present embodiment is the same as the thickness of the metal foil layer 10, but is preferably in the range of 1/2 to 1/12 of the thickness of the metal foil layer 10, more preferably Is in the range of 1/6 to 1/10.
Thus, by reducing the thickness of the organic insulating film 20, it is possible to suppress the decrease in flexibility as the film substrate 1. In addition, when the semiconductor element is resin-sealed, since the organic insulating film 20 is thin, it is possible to suppress the moisture in the layer from lowering the reliability of the semiconductor element.

  However, in the film substrate 1 of the present embodiment, the width of the metal foil layer 10 is wider than the width of the organic insulating film 20 as described later, and the perforation for transfer is formed in the metal foil layer 10 Conversely, the width of the organic insulating film 20 may be wider than that of the metal foil layer 10 to form perforations in the organic insulating film 20. In this case, it is preferable to use the organic insulating film 20 thicker than the metal foil layer 10 in the above range.

The adhesive layer 201 is formed of a thermosetting adhesive containing a polyamide resin as a main component. The adhesive layer 201 is used which is softened at a temperature of 80 ° C. to 120 ° C. and hardened at a temperature of 150 ° C. to 180 ° C. In addition, as a thermosetting component, in order to provide chemical resistance, a phenol resin (50 to 60 weight ratio) and an epoxy resin (9 to 88 weight ratio) are used together with a polyamide resin.
The thickness of the adhesive layer 201 is in the range of 1 to 50 μm.

As shown in FIG. 1 (b), the adhesive layer 201 of the present embodiment is filled with regularly arranged inorganic fillers 30. As shown in FIG.
As the inorganic filler 30 in the present embodiment, powdery silica is used, but powdery alumina, diatomaceous earth, stable metal oxides such as titanium oxide, zinc oxide, magnesium oxide and the like, and other inorganic pigments Or the like may be used.

The inorganic filler 30 has an average particle size P in the range of 0.1 to 30 μm.
When the thickness of the adhesive layer 201 is L, the particle diameter P of the inorganic filler 30 needs to be P <L. When the average particle diameter P is greater than or equal to the thickness L, the function of bonding the organic insulating film 20 and the metal foil layer 10 is lost.
In addition, as a shape of the inorganic filler 30, the particle | grains of various shapes, such as a spherical shape, a cube shape, tetrahedron shape, and what is called a 平 shape, are used. These shapes are different depending on the manufacturing process, and in the case of spherical shapes, they are formed by taking corners from a cubic shape, so while the average particle diameter is 0.1 to 30 μm, in other shapes 10 μm to It is in the range of 30 μm.

As shown in FIG. 1 (b), the particles of the inorganic filler 30 of the present embodiment are packed at regular intervals in a square lattice shape as a regular arrangement. In the inorganic filler 30, the spacing M1 of each particle is disposed, for example, every 0.2 to 60 μm, and the spacing (square side) M2 of the lattice is disposed at 0.4 to 120 μm (where M2 M M1). It is done.
By regularly arranging the inorganic fillers 30 in this manner, the flexibility of the film substrate 1 can be made uniform.

  In addition, the inorganic filler 30 is not limited to a square lattice shape as a regular arrangement, and may have other geometric shapes, for example, a triangular lattice shape, a rectangular lattice shape, a hexagonal lattice shape (honeycomb shape), a mesh mesh shape It may be in the form of bricks, etc. In addition, it may be a shape of a leaf pattern of hemp, or a shape of a leaf pattern of hemp.

  The regular arrangement of the inorganic fillers 30 is an arrangement as viewed from above, as shown in FIG. 1 (b). As shown in FIG. 1A, when viewed from the side, each inorganic filler 30 is preferably positioned approximately at the center of the thickness L of the adhesive layer 201, but not necessarily on the same plane. May be

  In addition, in the film substrate 1 of this embodiment, since it aims at manufacture of the flexible substrate which can be applied as a multipurpose substrate, for example, in order to make it useable also as a board | substrate for leaf spring switches besides a wiring board The thickness within the above range is required for the organic insulating film 20 and the adhesive layer 201. This is because if the thickness exceeds the above-mentioned set range, a problem arises in the flexibility of the entire TAB substrate required at the time of manufacture.

FIG. 2 shows an area where the adhesive layer 201 is filled with the inorganic filler 30 and an area where the adhesive layer 201 is not filled.
As shown in FIG. 2, in the adhesive layer 201, the specific regions 301 and 302 are filled with the inorganic filler 30, and the non-specific region 303 is not filled with the inorganic filler 30.
The specific region 301 and the specific region 302 are filled with the inorganic filler 30 in a regular arrangement, as described in FIG. 1 (b).

The specific areas 301 and 302 are determined by the wiring pattern for the wiring circuit formed in the metal foil layer 10, and an area where the influence of temperature or elongation due to moisture absorption is large, ie, an area where high positional accuracy is required is a specific area. It is decided. Depending on the degree of position accuracy required, it is divided into a specific area 301 for which higher accuracy is required, and a specific area 302 which may be less accurate.
The specific region 301 is filled with the inorganic filler 30 so as to have a higher density than the specific region 302. For example, in the specific region 301, the spacing of the square lattice-shaped grid shown in FIG. 1B is smaller than in the specific region 302 and / or the spacing between the particles of the inorganic filler 30 is narrowed. . However, it is also possible not to distinguish between the specific region 301 and the specific region 302, but to fill both with the same density.

Specifically, for example, the peripheral area of the IC hole 203 is determined to the specific area 301, the area to which the component is soldered, the area around the test lead, and the like are determined to the specific area 302.
On the other hand, the non-specific region 303 is determined for the other region, the positioning hole portion, the region other than the IC module (region between modules), and the region where high flexibility is required.

Although not shown in FIGS. 1 and 2, in the film substrate 1 of the present embodiment, perforations aligned in the longitudinal direction are formed on both sides in the width direction as described later (FIG. 4 (e2) reference).
The perforations 11 are used to move the film substrate 1 in the longitudinal direction by engaging with the sprockets of a manufacturing apparatus that sequentially forms an IC module or the like on the film substrate 1.

Next, a method of manufacturing the film substrate 1 configured as described above will be described.
FIG. 3 and FIG. 4 are explanatory views showing the state in the manufacturing process of the film substrate 1.
First, as shown in FIGS. 3 (a1) and 3 (a2), an organic insulating film 20 having a thermosetting adhesive layer 201 formed on one surface is prepared (preparation step).
In this embodiment, in the preparation step, the organic insulating film 20 is prepared in which the adhesive layer 201 is formed in advance on one surface, and the protective film 202 is attached to the surface of the adhesive layer 201. Since the organic insulating film 20 in this state is a commercially available product, the adhesive layer 201 is not filled with the inorganic filler 30.
FIG. 3 (a2) is a plan view of the organic insulating film 20, and FIG. 3 (a1) shows a cross section at a position corresponding to the dotted circle shown in this plan view (the same applies to the following).

Next, as shown in FIG. 3 (b 1) and (b 2), through holes are formed in the organic insulating film 20 and the adhesive layer 201 (through hole forming step). The through hole forming step is a step performed as needed.
For example, in the film substrate 1 of the present embodiment, through holes are formed in the metal foil layer 10 corresponding to the final product during or after the film substrate 1 is manufactured as a product.
In the through hole forming step, a through hole is formed by punching at a position of the organic insulating film 20 corresponding to the through hole to be formed later in the metal foil layer 10.
In the example shown in FIGS. 3 (b1) and 3 (b2), the IC holes 203 are punched out at positions corresponding to the through holes for the semiconductor element, and the through holes 204 corresponding to the other through holes are formed.

Next, as shown in FIG. 3C, the inorganic filler 30 is disposed on the upper surface of the adhesive layer 201 in a regular arrangement in the specific regions 301 and 302 (inorganic filler disposing step).
In this step, the attached protective film 202 is peeled off, and the particles of the inorganic filler 30 are arranged in a regular arrangement on the surface of the exposed adhesive layer 201.
In the present embodiment, as described in FIG. 1B as a regular arrangement, they are arranged in a square lattice. In addition, the inorganic filler 30 is disposed in the specific regions 301 and 302 described with reference to FIG. 2, and is not disposed on the upper surface of the nonspecific region 303.

In addition, each particle of the inorganic filler 30 is squared as shown in FIG. 1 (b) with respect to the specific regions 301 and 302 by a method such as dropping the inorganic filler 30 into a predetermined position using a mask plate. In addition to arranging in a grid shape at regular intervals, ink-like inorganic fillers may be arranged at regular intervals in a square grid shape.
Specifically, the inorganic filler 30 is mixed in a volatile solvent, and after being put into an ink state, the ink-like inorganic fillers are arranged at equal intervals by applying them to predetermined positions by inkjet. May be

Next, as shown in FIG. 4 (d 1), the metal foil layer 10 on which the wiring pattern for the wiring circuit will be formed later is provided on the top surface of the inorganic filler 30 provided (metal foil layer providing step) ).
FIG. 4 (d 2) represents the flat surface of the metal foil layer 10, and as described above, perforations 11 (perforation pitch = 4) are equally spaced along the length direction on both side surfaces in the width direction. .75 mm) is formed. The perforations 11 are formed by cutting out the end portions by punching.

  In the present embodiment, the metal foil layer 10 is wider than the organic insulating film 20, and the perforations 11 are formed in the metal foil layer 10. As described above, by forming the perforations 11 in the metal foil layer 10 that engage with the sprockets of the manufacturing apparatus to transfer the film substrate 1 in the longitudinal direction, it is possible to suppress the elongation and distortion when transferring the film substrate 1 Can be transported accurately.

However, on the contrary, the perforations 11 may be formed on both ends of the organic insulating film 20 wider than the metal foil layer 10. In this case, the perforations 11 may be formed together with the IC holes 203 and the other through holes 204 in the through hole forming step described with reference to FIGS. 3 (b1) and 3 (b2). Also, perforations 11 may be formed in advance.
Also, although the perforations 11 of the embodiment described above are formed by notches that leave no end, even if the end is left by forming a through hole inside the end, Good.
With regard to the shape of the perforations 11, various shapes such as circular and elliptical shapes can be adopted other than the rectangular shape regardless of the forming position, but in any case, the conveying means of the manufacturing apparatus (for example, sprockets Shape according to).

Next, by heating the adhesive layer 201, the inorganic filler 30 disposed on the upper surface is filled in the adhesive layer 201, and the organic insulating film 20 and the metal foil layer 10 are adhered (adhesion step) ).
That is, in the bonding step, after the metal foil layer 10 is placed on the disposed inorganic filler 30, the whole is heated at a temperature of 80 ° C. to 120 ° C. to soften the adhesive layer 201, and this heated state is Maintain for a predetermined time.
Thereby, the inorganic filler 30 which has been on the adhesive layer 201 (see FIG. 4 (d1)) is filled in the adhesive layer 201 as shown in FIG. 4 (e1). At this time, the inorganic filler 30 sinks into the adhesive layer 201 due to the weight and the self weight of the metal foil layer 10 placed on the top.

  The heating time of the adhesive layer 201 is the time for the inorganic filler 30 disposed on the upper surface to sink into the softened adhesive layer 201 so that the entire metal foil layer 10 comes in contact with the adhesive layer 201. Depending on the components of the layer 201, it is about 1 hour. More precisely, with respect to the adhesive layer 201 to be used, the time until the adhesive layer 201 and the metal foil layer 10 come in contact with each other, which has been previously examined in a plurality of experiments, is used.

After a predetermined time has passed, the inorganic filler 30 sinks, and in a state where the metal foil layer 10 is in contact with the adhesive layer 201, the adhesive layer 201 is cured to bond the metal foil layer 10. That is, the heating temperature is set to 150 ° C. to 180 ° C. which is the curing temperature of the adhesive layer 201, and the metal foil layer 10 is pressed in the direction of the organic insulating film 20 with a force of 1 kg per 1 cm 2.
By the above, as shown in FIG. 4 (e1) (e2), the film substrate 1 in which the metal foil layer 10 is adhered to the organic insulating film 20 by the adhesive layer 201 filled with the inorganic filler 30 is completed. .

Next, a method of manufacturing a TAB substrate using the film substrate 1 formed as described above will be described.
5 and 6 show steps of manufacturing a wiring substrate using the film substrate 1 of the present embodiment.
As shown in (f1) and (f2) in FIG. 5 (f1) (f2), the photoresist layer 111 is formed on the surface of the metal foil layer 10 opposite to the organic insulating film 20 (photoresist step).
The width of the photoresist layer 111 to be formed is the same as the width of the organic insulating film 20, but may be wider.
Although the formation of the photoresist layer 111 in the present embodiment is performed by roll coater application, it may be formed by laminating a dry film to be the photoresist layer 111 on the surface of the metal foil layer 10.

Next, as shown in FIG. 5 (g1), the photoresist layer 111 is irradiated with ultraviolet light 500 to transfer the lead pattern of the photomask (exposure step), and thereafter, the unexposed portion 112 is immersed in a developer. Remove (development step).
Further, after development, the solvent and moisture in the photoresist layer 111 are removed, and the remaining lead pattern portion is thermally crosslinked to improve adhesion with the metal foil layer 10.

Next, as shown in FIG. 5 (h1), the IC hole 203 and the through hole 204 are sealed by applying a backing material 205 on the surface of the organic insulating film 20 (backing process).
Although various materials can be used for the backing material 205 to apply | coat, a polyimide is used in this embodiment.
In the present embodiment, the backing material 205 is applied to the entire surface of the organic insulating film 20, but may be applied to a portion corresponding to the through holes 203 and 204.

Next, as shown in FIG. 6 (i1), the substrate is immersed in a ferric chloride aqueous solution to remove the metal portion 113 other than the lead pattern (etching step).
As a result, a conductor pattern layer (wiring circuit by the metal foil layer 10) having a predetermined pattern corresponding to the lead pattern formed on the metal foil layer 10 in the exposure and development steps is formed.
Thereafter, the photoresist layer 111 and the backing material 205 are peeled off (peeling step).

Next, as shown in (j1), gold plating 114 is applied to the exposed surface of the metal foil layer 10 formed in the lead pattern (plating step).
FIG. 6 (j2) is a plan view of a portion corresponding to the dotted circle in FIG. 3 (a2). In FIG. 6 (j 2), the portions shown by thick black lines are the lead patterns after the etching step, and inner leads (flying leads) 115 extending to the inside of the IC holes 203 for semiconductor elements are formed. .

Next, as shown in FIG. 6 (k1), the necessary portions of the lead pattern are covered and protected by the insulating film 116 by screen printing (solder resist process).
Finally, inspections of various inspection items such as etching defects, plating defects, foreign matter adhesion and the like are performed (inspection step).

The TAB substrate using the film substrate 1 of the present embodiment and the method for manufacturing the same have been described above.
On the other hand, in the case of a COF substrate, since a through hole for a semiconductor element or the like is not necessary, it is the same as the TAB substrate except that the processing for the formation of the through hole Can be formed.

In the embodiment described above, as shown in FIG. 1 and FIG. 2, the case where the inorganic filler 30 is filled in a regular arrangement in a square grid shape with respect to the specific regions 301 and 302 of the adhesive layer 201 is described. However, it is not limited to this.
FIG. 7 is an explanatory view showing a modified example of the region filled with the inorganic filler 30 and the filled state.
FIG. 7A shows an example in which the inorganic filler 30 is disposed on the entire adhesive layer 201 without distinguishing between the specific region and the non-specific region. In this case, as shown in FIG. 1 (b), the inorganic filler 30 is regularly arranged in the shape of various geometric patterns such as a square lattice shape and a honeycomb shape.
The IC holes 203 and the through holes 204 are formed in accordance with the requirements for the final product such as a wiring pattern.

On the other hand, FIG. 7 (b) is an example in which the inorganic filler 30 is filled in the specific regions 301 and 302 only and the non-specific region 303 is not filled as described in FIG.
In this case, the inorganic filler 30 is not packed in a regular arrangement, but is packed at a predetermined surface density or volume density.
The specific area 301 and the specific area 302 may have the same area density, but the area density of the specific area 301 that requires higher positional accuracy may be set higher.

In the method of manufacturing the film substrate 1 described above, the organic insulating film 20 on which the adhesive layer 201 is formed in advance is prepared in the preparation step, and the IC holes 203 and the through holes 204 are formed in this. The adhesive layer 201 may be formed in the preparation step.
That is, after the thermosetting adhesive that becomes the adhesive layer 201 is applied on the organic insulating film 20 and the protective film 202 is attached to the surface, the IC holes 203 and the through holes 204 may be formed. .
Alternatively, the IC holes 203 and the through holes 204 may be formed in the organic insulating film 20, and then the adhesive layer 201 may be formed. In this case, it is not necessary to attach the protective film 202 on the adhesive layer 201 because the process can immediately proceed to the next step.

As described above, according to the film substrate 1 of the present embodiment and / or the modification and the method of manufacturing the same, the following effects can be obtained.
(1) Since the inorganic filler 30 is filled in a regular arrangement at predetermined intervals in the adhesive layer 201, the film in the specific area is filled regardless of whether the area to be filled is the entire adhesive layer 201 or a specific area. The flexibility of the substrate 1 can be made uniform.
(2) By providing the specific regions 301 and 302 for filling the inorganic filler 30 in the adhesive layer 201 and the non-specific regions for no filling, regardless of whether or not the inorganic filler 30 is filled in a regular arrangement, For example, high flexibility requirements can be met.
(3) By providing the specific region 301 and the specific region 302, the inorganic filler 30 can be filled at a filling density according to the requirement of the positional accuracy.
(4) Since the adhesive layer 201 is filled with the inorganic filler 30 with the region required to have high positional accuracy as the specific region, it is possible to suppress the temperature of the organic insulating film 20 and the elongation due to moisture absorption in the region it can.

DESCRIPTION OF SYMBOLS 1 film substrate 10 metal foil layer 11 perforation 20 organic insulating film 201 adhesive layer 30 inorganic filler 301, 302 specific area 303 non-specific area 111 photoresist layer 112 unexposed part 113 metal part other than lead pattern 114 gold plating 115 inner Lead 116 Insulating film 202 Protective film 203 IC hole 204 Other through holes 205 Backing material

Claims (9)

A metal foil layer on which a wiring pattern for a wiring circuit is formed;
Insulation film,
An adhesive layer for bonding the metal foil layer and the insulating film;
The adhesive layer is filled with an inorganic filler in a regular arrangement,
A film substrate characterized by In the adhesive layer, the inorganic filler is arranged in a geometric lattice pattern.
The film substrate according to claim 1, The adhesive layer is filled with the inorganic filler to a specific area,
The film substrate according to claim 1 or 2, characterized in that: The adhesive layer is filled with the inorganic filler at a different filling density depending on the specific area.
The film substrate according to claim 3, characterized in that: The specific region is determined according to the wiring pattern formed on the metal foil layer.
The film substrate according to claim 3 or 4 characterized by things. The insulating film has an IC hole formed therein.
The adhesive layer is filled with the inorganic filler at least in a peripheral region of the IC hole.
The film substrate according to claim 1, 2 or 3, characterized in that: The adhesive layer is a thermal effect adhesive layer,
The film substrate according to any one of claims 1 to 6, characterized in that: A metal foil layer on which a wiring pattern for a wiring circuit is formed;
Insulation film,
An adhesive layer for bonding the metal foil layer and the insulating film;
The adhesive layer has a specific area filled with an inorganic filler and a non-specific area not filled with an inorganic filler.
A film substrate characterized by Preparing an insulating film having a thermosetting adhesive layer formed on one side thereof;
An inorganic filler disposing step of disposing an inorganic filler on the upper surface of the adhesive layer in a regular arrangement and / or in a specific area;
A metal foil layer disposing step of disposing a metal foil layer on which a wiring pattern for a wiring circuit is formed on the upper surface of the inorganic filler disposed;
Bonding the inorganic filler disposed on the upper surface into the adhesive layer by heating the adhesive layer, and bonding the insulating film and the metal foil layer;
A method of manufacturing a film substrate, comprising:

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