JP2006148072A - Wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring board capable of improving reliability in junction of the wiring board and parts by improving accuracy in the position of a connection land. <P>SOLUTION: The wiring board 50 is provided with an insulating layer 52, a connection land 54 provided on one surface 52a of the insulating layer 52, and a copper layer 58 provided in a predetermined region R2 on the other surface 52b of the insulating layer 52. The connection land 54 is disposed in a region R1 corresponding to the predetermined rejoin R2 on the surface 54a. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a wiring board.

In recent years, electronic devices are becoming lighter, thinner, and smaller, and the demand for high-density mounting tends to increase. For this reason, not only the formation of a high-density wiring pattern in a wiring board but also the use of a thinner substrate or a flexible substrate is required for mounting in a space-saving manner. In response to this trend, copper foil-clad flexible substrates with adhesives based on polyimide films, copper-clad flexible substrates with polyimide resin as an insulating layer without using adhesives, and sputtering on polyimide film surfaces After forming a copper layer thinly by the method etc., the flexible substrate which gave electrolytic copper plating is used (for example, refer patent documents 1 and patent documents 2).
JP-A-5-347461 JP-A-8-250860

  However, when connecting the connection land of the wiring board manufactured using the substrate as described above and the high-density terminal of the long size IC with an anisotropic conductive film (ACF), the connection land and the transparent conductive film When bonding a glass substrate having a high density ITO (indium tin oxide) terminal that is an anisotropic conductive film (ACF), the connection between the connection land of the wiring board and the terminal such as an IC is incomplete A bug that occurred has appeared. One of the causes is that the distortion of the insulating layer in the manufacturing process of the flexible substrate and the manufacturing process of the wiring board is released when the copper pattern is formed, so that the positional accuracy of the connection lands on the wiring board is reduced. This is because the position of the connection land and the position of the terminal to be joined such as an IC become inconsistent.

  An object of the present invention is to provide a wiring board capable of improving the reliability of joining between a wiring board and a component by improving the positional accuracy of a connection land.

  In order to solve the above-described problems, a wiring board of the present invention is provided on an insulating layer, a connection land provided on one surface of the insulating layer, and a predetermined region on the other surface of the insulating layer. The connection land is disposed in a region corresponding to the predetermined region on the one surface.

  In the wiring board of the present invention, the copper layer supports the insulating layer. For this reason, it is difficult to release the strain in the insulating layer. Therefore, since the positional accuracy of the connection land is improved, the reliability of bonding between the wiring board and other components can be improved.

  The wiring board of the present invention includes an insulating layer, alignment marks and connection lands provided on one surface of the insulating layer, and a copper layer provided on a predetermined region on the other surface of the insulating layer. The alignment mark and the connection land are arranged in a region corresponding to the predetermined region on the one surface.

  In the wiring board of the present invention, the copper layer supports the insulating layer. For this reason, it is difficult to release the strain in the insulating layer. Therefore, since the positional accuracy of the connection land and the alignment mark is improved, it is possible to improve the reliability of bonding between the wiring board and other components.

  Moreover, it is preferable that an opening is formed in the copper layer. In this case, heat dissipation from the copper layer can be suppressed.

  Moreover, it is preferable that the thickness of the said insulating layer is 20-100 micrometers. When the thickness of the insulating layer is less than 20 μm, the handleability of the wiring board tends to deteriorate. On the other hand, when the thickness of the insulating layer exceeds 100 μm, for example, the work of joining the wiring board and the component using an anisotropic conductive film tends to take time, and the insulating layer is easily damaged by heat at the time of joining. Tend to be.

In addition, the following wiring boards (1) to (4) are also preferable.
(1) In a wiring board comprising an insulating layer, a connection land provided on one surface of the insulating layer, and a continuous copper layer provided on the other surface of the insulating layer, the continuous copper layer is electrically connected to the connection land and A wiring board provided in a region that does not have a general connection and covers the position directly below the connection land.
(2) In a wiring board comprising an insulating layer, alignment marks and connection lands provided on one surface of the insulating layer, and a continuous copper layer provided on the other surface of the insulating layer, the continuous copper layer is A wiring board provided in a region that is not electrically connected to the alignment mark and the connection land and covers the position directly below the alignment mark and the connection land.
(3) The wiring board according to item (1) or (2), wherein the continuous copper layer is a continuous copper layer provided with a circular, elliptical, or polygonal copper removal portion.
(4) The wiring board according to any one of Items (1) to (3), wherein the insulating layer has a thickness of 20 to 100 μm.

  ADVANTAGE OF THE INVENTION According to this invention, the wiring board which can improve the reliability of joining of a wiring board and components by improving the position accuracy of a connection land is provided.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same reference numerals are used for the same or equivalent elements, and duplicate descriptions are omitted.

  FIG. 1 is a diagram schematically illustrating a wiring board according to an embodiment. FIG. 1A is a plan view schematically showing a wiring board according to the embodiment. FIG. 1B is a cross-sectional view taken along the line IB-IB shown in FIG. FIG. 1C is a plan view schematically showing the wiring board according to the embodiment as viewed from the side opposite to FIG.

  The wiring board 50 shown in FIG. 1 is preferably a flexible board or a printed wiring board. The wiring board 50 includes an insulating layer 52, a connection land 54 provided on one surface 52a of the insulating layer 52, and a copper layer 58 provided on a predetermined region R2 on the other surface 52b of the insulating layer 52. Is provided.

  The connection land 54 is disposed in a region R1 corresponding to the predetermined region R2 on the surface 52a. The region R1 overlaps the region R2 when viewed from the thickness direction of the insulating layer 52. The connection land 54 is made of a conductor pattern such as a copper pattern, for example.

  The copper layer 58 is preferably an integrated isolated pattern. The copper layer 58 is preferably provided so as to cover the predetermined region R2, and more preferably provided so as to cover the entire surface 52b. The copper layer 58 is preferably electrically insulated from the connection land 54.

  In the wiring board 50 of this embodiment, the copper layer 58 supports the insulating layer 52. For this reason, the strain energy in the insulating layer 52 is difficult to be released. Therefore, since the insulating layer 52 is not deformed, the positional accuracy of the connection land 54 is improved. Therefore, it is possible to improve the reliability of bonding between the wiring board 50 and other components (for example, a semiconductor chip or a glass substrate).

  Moreover, it is preferable that the wiring board 50 is provided with the alignment mark 56 provided on the surface 52a. The alignment mark 56 is preferably arranged in the region R1. In this case, since the positional accuracy of the alignment marks 56 in addition to the connection lands 54 is improved, it is possible to improve the reliability of bonding between the wiring board 50 and other components. The alignment mark 56 is preferably electrically insulated from the copper layer 58. The alignment mark 56 is made of a conductor pattern such as a copper pattern, for example.

  The copper layer 58 is preferably formed with an opening 60. In this case, heat dissipation from the copper layer 58 can be suppressed. The shape of the opening 60 is preferably, for example, a circle, an ellipse, or a polygon. A plurality of openings 60 may be provided.

  Moreover, it is preferable that the thickness d of the insulating layer 52 is 20-100 micrometers. When the thickness d of the insulating layer 52 is less than 20 μm, the handleability of the wiring board 50 tends to deteriorate. On the other hand, when the thickness d of the insulating layer 52 exceeds 100 μm, for example, the work of joining the wiring board 50 and the component using an anisotropic conductive film tends to take time, and the insulating layer 52 is caused by heat at the time of joining. It tends to be easily damaged.

  Although it does not specifically limit as a resin composition which forms the insulating layer 52, A thermoplastic resin, a thermosetting resin, etc. can be used, A thermosetting resin is preferable. Examples of the thermosetting resin include epoxy resins, polyimide resins, unsaturated polyester resins, polyurethane resins, bismaleimide resins, triazine-bismaleimide resins, and phenol resins. The insulating layer 52 may be made of a film-like thermosetting resin composition that does not contain a fiber base material such as glass cloth, or from a resin composition in which a fiber base material such as glass cloth is impregnated with a thermosetting resin. It may be. Therefore, for example, a copper-clad film in which a copper foil is bonded to a polyimide film using a thermosetting adhesive, or a copper-clad adhesive that is bonded to a copper foil by pressure heating after impregnating a glass cloth with a thermosetting resin such as an epoxy resin. The wiring board 50 may be manufactured using a laminated board. The insulating layer 52 preferably has a thickness of 20 to 100 μm. When the thickness is less than 20 μm, the strength of the wiring board 50 is lowered and handling properties are deteriorated. When it is thicker than 100 μm, it takes time to join the parts with the anisotropic conductive film to the wiring board 50 and heat due to the bonding. The insulating layer 52 is damaged.

  In the wiring board 50, the connection land 54, or the alignment mark 56 and the connection land 54 are provided on one surface (surface 52 a) of the insulating layer 52. The alignment mark 56 and the connection land 54 are preferably formed from metal, and more preferably formed from copper. The alignment mark 56 and the connection land 54 are preferably formed from a metal layer, and more preferably from a copper layer. As the copper layer (conductor layer), in addition to the electrolytic copper foil and the rolled copper foil, about 200 to 500 mm of nickel, chromium, copper or the like was deposited on the insulating layer 52 by sputtering, and then electroplated with copper. Things can be used. The thickness of the copper layer may be selected in the range of 3 to 70 μm depending on the purpose, and more preferably in the range of 9 to 35 μm. Note that the wiring board 50 may be formed with other wiring patterns on the surface (surface 52a) of the insulating layer 52 as needed, in addition to the alignment marks 56 and the connection lands 54.

  For example, the wiring board 50 is manufactured by forming a photosensitive etching resist on a copper layer and then exposing the photomask repeatedly, removing the unexposed etching resist, selectively etching copper, and stripping the exposed etching resist. A subtracting method comprising a step of removing and forming at least the connection land 54 or the connection land 54 and the alignment mark 56 and the continuous copper layer 58 at a desired position can be used.

  A continuous copper layer 58 is provided on the other surface 52b of the insulating layer 52, that is, the surface opposite to the connection land 54 or the surface 52a on which the alignment mark 56 and the connection land 54 are provided. The size of the copper layer 58 only needs to cover at least the connection land 54 on the surface (surface 52a) of the insulating layer 52 and the position immediately below the alignment mark 56, but is preferably as large as possible. It is more preferable that the size of the surface 52b is completely covered. Note that when the other surface 52 b of the insulating layer 52 is entirely covered, the end portion of the wiring board 50 may not be covered with the continuous copper layer 58. The size and shape of the connection land 54 and the alignment mark 56 on the surface of the insulating layer 52 (surface 52a) are not particularly limited, but it protrudes from the area covered by the continuous copper layer 58 provided immediately below. If not, it ’s good. When the continuous copper layer 58 has a size that cannot cover the connection land 54 on the surface (surface 52a) of the insulating layer 52 and the position immediately below the alignment mark 56, the dimensional stability of the intended wiring board 50 is improved. descend. Further, when recognizing the alignment mark 56 from the other surface 52b, it is preferable to provide a copper removal portion (opening 60) in the continuous copper layer 58 at the corresponding position on the other surface 52b. And by providing the copper removal part (opening 60) in the copper layer 58, the heat dissipation at the time of component joining is suppressed, and the reliability of component joining improves. In addition, as a shape of a copper removal part (opening 60), circular shape, ellipse shape, or polygonal shape is preferable.

  The continuous copper layer 58 provided on the other surface 52b of the insulating layer 52 is electrically connected to the connection land 54 provided on one surface (surface 52a) of the insulating layer 52, or the alignment mark 56 and the connection land 54. There is no connection. The continuous copper layer 58 is preferably not electrically connected to other wiring patterns provided on one surface (surface 52a) of the insulating layer 52 other than the alignment marks 56 and the connection lands 54.

  As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment.

  In this embodiment, the reliability of component joining can be improved by improving the positional accuracy of the connection land 54 of the wiring board 50 and the positional accuracy of the alignment mark 56 with the component.

  Further, in this embodiment, the continuous copper layer 58 suppresses the release of the remaining strain in the insulating layer 52, so that the connection land 54 and the alignment mark 56 have excellent positional accuracy, and the component bonding It is possible to provide the wiring board 50 excellent in improving the reliability.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Example 1
The wiring board of Example 1 is shown in FIGS. The wiring board of the present embodiment has the connection land 2 and the alignment mark 3 with excellent positional accuracy on the surface of the insulating layer 1 having a thickness of 50 μm, and the position immediately below the connection land 2 and the alignment mark 3. It is a wiring board provided in a region 17 covered by a continuous copper layer 4. The continuous copper layer 4 is present on the opposite surface (back surface) of the connection land 2 and the alignment mark 3 and is not electrically connected to the connection land 2 and the alignment mark 3. The wiring board was coated with an acrylic-modified epoxy resin 6 having the following composition on both surfaces of a glass cloth 5 (trade name: # 1037, manufactured by Nitto Boseki Co., Ltd.), dried at 150 ° C. for 5 minutes, and then copper foil (Product name: SLP-18, manufactured by Nippon Electrolytic Co., Ltd.) is placed on both sides, and a copper pattern is etched by etching the copper foil using a double-sided copper-clad laminate that is heated under pressure at 170 ° C. for 30 minutes. It produced by forming.

  As a composition of the acrylic modified epoxy resin 6, acrylic resin HTR-860PS (trade name, manufactured by Nagase ChemteX Corporation): 100 parts by weight (parts by mass), epoxy resin Epicoat 828 (trade name, manufactured by Yuka Shell Co., Ltd.) : 60 parts by weight, novolak phenol resin VP 6371 (trade name, manufactured by Hitachi Chemical Co., Ltd.): 40 parts by weight, imidazole 2PZ-CN (trade name, manufactured by Shikoku Chemicals Co., Ltd.): 0.4 part by weight.

(Example 2)
The wiring board of Example 2 is shown in FIGS. In this embodiment, an epoxy resin adhesive 7 (manufactured by Nikkan Kogyo Co., Ltd.) is formed on the front and back of the Kapton film 8 (trade name, manufactured by Toray DuPont Co., Ltd., polyimide resin), and a commercially available copper foil 15 is disposed. A copper-clad film (trade name, F50VC212RC21 / 2 (H), manufactured by Nikkan Kogyo Co., Ltd.) was used. In this embodiment, a circular copper removing portion 9 is provided on the continuous copper layer 4 provided on the back surface of the insulating layer 1 (see FIGS. 5 and 6).

Hereinafter, the manufacturing method will be described with reference to FIG. Etching resist 10 (trade name, NIT215, manufactured by Nippon Synthetic Chemical Co., Ltd.) on the above-mentioned commercially available copper-clad film (FIG. 7A, insulating layer thickness: 36 μm, copper foil thickness: 18 μm) is 110 ° C., 3.5 kg. After lamination under the conditions of 1.0 cm / min / cm ² , pattern negative photographs are overlaid and exposed with UV light (exposure amount: 100 mJ / cm ² ). After the exposure, development was performed by spraying using a 1.3% by weight aqueous solution of sodium carbonate (35 ° C.) to form an etching resist image (FIG. 7B). Next, an aqueous solution of cupric chloride at 50 ° C. was sprayed, and the copper foil 15 was etched to form a copper pattern including the connection land 2 and a continuous copper layer 4 covering the position immediately below the connection land 2 (FIG. 7). (C)). The continuous copper layer 4 is not electrically connected to the connection land 2. After the etching, a 1.5% by weight aqueous solution of sodium hydroxide (40 ° C.) was sprayed, and the etching resist was peeled off to produce a wiring board of this example (FIG. 7D).

(Example 3)
In this example, the glass cloth 5 was changed from the product name # 1037 (manufactured by Nitto Boseki Co., Ltd.) to the product name # 5005 (manufactured by Asahi Shovel Co., Ltd.), and the thickness of the insulating layer was changed to 100 μm. Same as 1.

(Comparative Example 1)
The wiring board of Comparative Example 1 is shown in FIG. This comparative example is the same as Example 1 except that the continuous copper layer 4 on the opposite surface (back surface) is removed.

  Table 1 shows the characteristic results of the wiring boards obtained in the above examples and comparative examples. The characteristic evaluation method is as follows.

(Measurement of dimensional change rate)
Fixed points were provided at the ends of the 250 mm square Examples 1 and 3 and the double-sided copper clad laminates of Comparative Example 1 and the 250 mm square Example 2 copper-clad film, and the dimensions were measured. Furthermore, the copper foil was etched to form a copper pattern to produce a wiring board, its dimensions were measured, and the dimensional change rate before and after the copper pattern was formed was calculated.

(Evaluation of solder heat resistance)
The double-sided copper-clad laminates of Examples 1 and 3 and Comparative Example 1 and the copper-clad film of Example 2 were floated in a solder bath at 260 ° C. for 20 seconds to evaluate solder heat resistance. The appearance of abnormalities such as blistering and peeling was examined.

(Reliability evaluation of component bonding)
The following evaluation was performed as reliability of component joining. Using the double-sided copper-clad laminates of Examples 1 and 3 and Comparative Example 1 and the copper-clad film of Example 2, a wiring board having the wiring pattern shown in FIG. 9 was produced. Except for Comparative Example 1, the opposite surface (back surface) of the wiring pattern shown in FIG. 9 covers the position immediately below the alignment mark 3 and the connection land 2 (ACF connection resistance measurement land 11). A continuous copper layer 4 was provided. The continuous copper layer 4 is not electrically connected to the connection land 2 and the alignment mark 3. Further, the glass substrate 14 having the ITO (indium tin oxide) pattern 12 and the alignment mark 16 shown in FIG. The wiring board and the glass substrate 14 are subjected to a heating head temperature of 290 ° C., a pressure of 3 MPa, and a joining time of 20 to 60 seconds using an ACF (anisotropic conductive film, trade name AC2102, manufactured by Hitachi Chemical Co., Ltd.). Then, the alignment marks for each other were aligned and adhered.

  As the ACF adhesiveness, the bonded wiring board and glass substrate were peeled off under the condition of 50 mm / min, and a 90 degree peel test was conducted. The results are shown in Table 1 as ACF adhesion for each joining time. Further, the appearance of the insulating layer of the wiring board after component bonding (ACF adhesion) was examined. Further, as an ACF connection resistance between the bonded wiring board and the glass substrate, an initial resistance value and a resistance value after a heating and humidifying test of 85 ° C., 85%, 1000 Hr were measured.

  From the characteristic results shown in Table 1, Examples 1 to 3 provided with a continuous copper layer 4 on the opposite surface (back surface) had a smaller dimensional change rate and superior dimensional stability compared to Comparative Example 1, and ACF. It has been confirmed that it has excellent properties for joining parts, such as low connection resistance.

It is a figure which shows typically the wiring board which concerns on embodiment. (Example 1) which is the surface shape figure of a wiring board. (Example 1) which is an opposite surface (back surface) shape figure of a wiring board. (Example 1) which is sectional drawing of a wiring board. (Example 2) which is sectional drawing of a wiring board. (Example 2) which is the opposite surface (back surface) shape figure which provided the circular copper foil removal part of the wiring board. It is sectional drawing which showed the manufacturing process of the wiring board (Example 2). It is sectional drawing of a wiring board (comparative example 1). It is a pattern diagram of a wiring board for reliability evaluation of component joining. It is a pattern diagram of the glass substrate for reliability evaluation of component joining.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insulation layer 2 Connection land 3 Positioning mark 4 Continuous copper layer 5 Glass cloth 6 Acrylic modified epoxy resin 7 Epoxy resin adhesive 8 Kapton film (polyimide resin)
9 circular copper removal part 10 etching resist 11 ACF connection resistance measurement land 12 ITO pattern 13 copper foil 14 glass substrate 15 copper foil 16 alignment mark 17 region 50 covered by continuous copper layer 50 wiring board 52 insulating layer 52a insulation One surface 52b of the layer The other surface 54 of the insulating layer 54 The connection land 56 The alignment mark 58 The copper layer 60 The opening R1 The region R2 corresponding to the predetermined region The predetermined region

Claims (4)

An insulating layer;
A connection land provided on one surface of the insulating layer;
A copper layer provided on a predetermined region on the other surface of the insulating layer;
With
The said connection land is a wiring board arrange | positioned in the area | region corresponding to the said predetermined area | region in said one surface. An insulating layer;
Alignment marks and connection lands provided on one surface of the insulating layer;
A copper layer provided on a predetermined region on the other surface of the insulating layer;
With
The wiring mark, wherein the alignment mark and the connection land are disposed in a region corresponding to the predetermined region on the one surface.   The wiring board according to claim 1, wherein an opening is formed in the copper layer.   The thickness of the said insulating layer is a wiring board as described in any one of Claims 1-3 which is 20-100 micrometers.

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