WO2010103721A1 - Circuit board - Google Patents
Circuit board Download PDFInfo
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- WO2010103721A1 WO2010103721A1 PCT/JP2010/000658 JP2010000658W WO2010103721A1 WO 2010103721 A1 WO2010103721 A1 WO 2010103721A1 JP 2010000658 W JP2010000658 W JP 2010000658W WO 2010103721 A1 WO2010103721 A1 WO 2010103721A1
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- WIPO (PCT)
- Prior art keywords
- layer
- signal wiring
- circuit board
- ground layer
- insulator layer
- Prior art date
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
- H05K1/0237—High frequency adaptations
- H05K1/025—Impedance arrangements, e.g. impedance matching, reduction of parasitic impedance
- H05K1/0253—Impedance adaptations of transmission lines by special lay-out of power planes, e.g. providing openings
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/0213—Electrical arrangements not otherwise provided for
- H05K1/0237—High frequency adaptations
- H05K1/0245—Lay-out of balanced signal pairs, e.g. differential lines or twisted lines
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K1/00—Printed circuits
- H05K1/02—Details
- H05K1/03—Use of materials for the substrate
- H05K1/0393—Flexible materials
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/09—Shape and layout
- H05K2201/09209—Shape and layout details of conductors
- H05K2201/09218—Conductive traces
- H05K2201/09272—Layout details of angles or corners
-
- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
- H05K2201/00—Indexing scheme relating to printed circuits covered by H05K1/00
- H05K2201/09—Shape and layout
- H05K2201/09209—Shape and layout details of conductors
- H05K2201/09654—Shape and layout details of conductors covering at least two types of conductors provided for in H05K2201/09218 - H05K2201/095
- H05K2201/09681—Mesh conductors, e.g. as a ground plane
Definitions
- the present invention relates to a ground layer and a circuit board in which signal wirings are arranged with respect to the ground layer via an insulator layer.
- the characteristic impedance (hereinafter also referred to as Zo) of the signal transmission path is matched to the input / output impedance of the device in order to suppress signal reflection and waveform distortion. It is necessary to let In order to match the characteristic impedance of the signal transmission path described above, a strip structure or a microstrip structure in which a ground layer is opposed to a signal transmission path (strip line) having an appropriate pattern width with an insulating layer having an appropriate thickness interposed therebetween is used. It has been adopted.
- the ground layer in the circuit board structure described above serves as an electrical reference plane that defines the characteristic impedance of the signal transmission path.
- the characteristic impedance is often selected to be around 50 ⁇ for single end and around 100 ⁇ for differential transmission.
- the characteristic impedance of the circuit board is the ratio of the reactance L per unit length of the signal transmission path and the capacitance C per unit area between the signal transmission path and the ground layer (reactance L / static It is a value approximated by the square root of the capacitance C).
- the signal transmission path for the ground layer is naturally used.
- the interlayer is narrow (thin), and the value of the capacitance C between them increases almost in inverse proportion to the dimension between the layers. Therefore, in order to obtain the desired Zo in the thin multilayer circuit board, the width of the signal transmission path (hereinafter also referred to as signal wiring) is larger than that of a conventional circuit board having a thick interlayer. By forming it narrow (narrow), it is necessary to adopt means for suppressing the increase in the capacitance C.
- the ground layer formed as a so-called solid electrode layer is removed in a mesh shape so that the opposing area between the ground layer and the signal wiring per unit area is substantially reduced. Proposals have been made to ensure the width of the signal wiring by making it smaller. This is disclosed in the following prior art documents.
- FIG. 7 shows a configuration example of the circuit board shown in the above-mentioned prior art document. This shows an example in which the direction of the signal wiring is bent about 45 degrees in the middle. That is, FIG. 7 shows a state in which, for example, signal wirings 3a and 3b for performing differential transmission arranged in parallel to each other are superimposed on a mesh pattern in which parallelogram-shaped openings are regularly formed in the ground layer 6. It is shown in a state seen through from a direction orthogonal to the circuit board surface.
- a large number of parallelogram (diamond) meshes are opened in the ground layer 6 by lines intersecting in two directions. Then, the crossing angle of the lines in the two directions on the ground layer 6 side with respect to the signal wirings 3a and 3b in the lower half part of the diagram indicated by the symbol A, and the ground layer for the signal wirings 3a and 3b in the upper half part of the diagram indicated by the symbol B
- the crossing angles of the two-direction lines on the 6 side are configured to be substantially the same. Thereby, it is possible to prevent the characteristic impedance of the signal wirings 3a and 3b bent in the middle from changing greatly in the regions A and B.
- the conductor is applied to the entire surface of the ground layer (solid electrode).
- the DC resistance value of the ground layer increases. For this reason, for example, a part of the ground layer away from the earth point is excited by receiving a high-frequency signal, the signal wiring is subject to spurious interference due to the high-frequency signal, or the leakage of the high-frequency signal flowing through the signal wiring becomes severe. Invite problems.
- the present invention has been made by paying attention to the technical problems described above, and can sufficiently control the characteristic impedance of the signal wiring and suppress the increase in the resistance value of the ground layer. It is an object of the present invention to provide a circuit board that can sufficiently exhibit countermeasures such as spurious interference.
- the circuit board according to the present invention which has been made to solve the above-described problems, includes a ground layer and a signal wiring disposed through an insulator layer with respect to the ground layer, and capacitive coupling between the ground layer and the signal wiring.
- a circuit board in which the characteristic impedance of the signal wiring is controlled and the conductive portion forming the ground layer is provided with a number of holes at positions facing the signal wiring.
- the mesh-like conductor part it is configured to control the capacitive coupling between the ground layer and the signal wiring, and a solid electrode region not formed with a hole is formed outside the mesh-like conductor part. It is characterized by being.
- the distance U between the signal wiring and the solid electrode region is set in a range of 20t ⁇ U ⁇ 3t, where t is the thickness of the insulator layer. This effect can be exhibited remarkably in a thin circuit board in which the insulator layer has a thickness of 100 ⁇ m or less.
- the plurality of holes formed in the mesh-like conductor portion are formed in a shape in which a plurality of lines in two directions intersect to form a parallelogram opening.
- the insulator layer is configured such that the signal wiring is laminated on one surface and the ground layer is disposed on the other surface.
- the signal wiring is formed on the insulator layer, and the ground layer is stacked via a second insulator layer covering the signal wiring on the insulator layer.
- the insulator layer has the signal wiring laminated on one surface, the ground layer is disposed on the other surface, and the signal wiring on the insulator layer is arranged.
- the second ground layer is stacked via the covering second insulator layer.
- the insulator layer is preferably configured using a film-like base substrate.
- the conductive portion constituting the ground layer at the position facing the signal wiring is formed into a mesh-shaped conductor portion in which a large number of holes are formed, so that the signal wiring facing the signal wiring
- the characteristic impedance can be adjusted.
- the said conductive part in the position away from the said signal wiring is made into the solid electrode area
- the thickness t of the insulator layer separating the signal wiring and the ground layer dominates the degree of capacitive coupling between them, and when the thickness t of the insulator layer is used as a parameter, the signal wiring Is set to a range of 20t ⁇ U ⁇ 3t, thereby satisfying the condition for adjusting the characteristic impedance of the signal wiring and securing a low DC resistance value as a ground layer. To be.
- the above range can be applied to a circuit board that is thinly formed as a whole with the thickness t of the insulator layer separating the signal wiring and the ground layer being 100 ⁇ m or less, whereby a more preferable result can be obtained.
- a circuit board having excellent flexibility can be obtained by using a film-like base substrate.
- a film-like base substrate When, for example, polyimide is used for the base substrate, heat resistance and mechanical properties are also excellent.
- a flexible circuit board can be provided.
- FIG. 1 is a laminated structure diagram of a circuit board showing a first embodiment according to the present invention.
- FIG. FIG. 2 is a perspective view showing a configuration of a part of a ground layer and signal wiring used in the circuit board shown in FIG. 1. It is sectional drawing explaining the relationship between the signal wiring which interposed the insulator layer, and the ground layer. It is the diagram which showed the relationship of the impedance of the track
- FIG. 3 is a laminated structure diagram of a circuit board showing a second embodiment according to the present invention in which the configuration of the ground layer shown in FIG. 2 is adopted. It is the laminated structure figure of the circuit board which similarly showed 3rd Embodiment. It is the perspective view which showed the structure of a part of ground layer and signal wiring in the conventional circuit board.
- FIG. 1 shows a laminated structure of a circuit board showing the first embodiment.
- a circuit board 1 shown in FIG. 1 constitutes a microstrip structure in which a signal wiring is arranged with respect to a ground layer and an insulating layer with respect to the ground layer.
- the insulating layer As shown, a film-like base substrate 2 is employed.
- signal wirings 3a and 3b for differential transmission are formed on one surface (upper side in FIG. 1) of the base substrate 2, and the upper surfaces (upper side in FIG. 1) of the signal wirings 3a and 3b are formed.
- An insulating layer 4a functioning as a second insulator layer is stacked.
- a first covering layer 5a is provided on the upper surface of the insulating layer 4a.
- a ground layer 6 is formed on the other surface (lower side in FIG. 1) of the base substrate 2, and an insulating layer 4b functioning as a third insulator layer is formed on the lower surface of the ground layer 6, Further, a second coating layer 5b is formed on the lower surface.
- the base substrate 2 that functions as a central insulator layer constituting the microstrip structure also has a function as a core of the circuit board 1.
- Examples of the material of the base substrate 2 include a resin film and a fiber substrate.
- the material constituting the resin film examples include polyimide resins such as polyimide resins, polyamide resins, and polyamideimide resins, thermosetting resins such as epoxy resins, and thermoplastic resins such as liquid crystal polymers.
- a polyimide resin or a liquid crystal polymer is preferable.
- polyimide resin it is excellent in heat resistance and mechanical properties and is easy to obtain.
- a liquid crystal polymer it is suitable for high-speed signal transmission due to its low relative dielectric constant, and it has excellent dimensional stability due to its low hygroscopicity.
- the fiber base material used for the insulating layer examples include glass fiber base materials such as glass fiber cloth and glass non-fiber cloth, or inorganic fiber base materials such as fiber cloth and non-fiber cloth containing inorganic compounds other than glass, aromatic And organic fiber base materials composed of organic fibers such as aromatic polyamide resins, polyamide resins, aromatic polyester resins, polyester resins, polyimide resins, and fluororesins.
- glass fiber base materials represented by glass fiber fabric are preferable in terms of strength and water absorption.
- a fiber base material When a fiber base material is used for the insulator layer, it is preferably used in a state where the fiber base material is impregnated with a resin.
- a resin impregnated in the fiber base material a thermosetting resin such as an epoxy resin or an acrylic resin is preferably used, and among these, an epoxy resin is preferable from the viewpoint of heat resistance.
- the thickness of the base substrate 2 is preferably in the range of 1 to 100 ⁇ m, more preferably in the range of 5 to 50 ⁇ m, and more preferably in the range of 10 to 30 ⁇ m.
- the thickness of the base substrate 2 is preferably in the range of 1 to 100 ⁇ m, more preferably in the range of 5 to 50 ⁇ m, and more preferably in the range of 10 to 30 ⁇ m.
- the signal wirings 3a and 3b arranged on one surface of the base substrate 2 may be provided directly on the base substrate 2, or may be provided via an adhesive. Then, at the end portion of each signal wiring or an appropriate intermediate portion, it is bonded to a mounting pad such as a semiconductor device (not shown) and functions as the circuit board 1.
- Examples of the insulating layer 4a covering the signal wirings 3a and 3b include acrylic resin, epoxy resin, polyimide resin, and liquid crystal polymer. Among these, an epoxy resin is preferable. Thereby, heat resistance and flexibility can be improved. On the other hand, when the liquid crystal polymer is used, it is possible to take advantage of the characteristics of a low relative dielectric constant and excellent high-speed signal transmission characteristics.
- the thickness of the insulating layer 4a is not particularly limited, but is preferably 5 to 40 ⁇ m, and particularly preferably 10 to 30 ⁇ m. By making the thickness of the insulating layer 4a equal to or higher than the lower limit value, it is possible to suppress a decrease in circuit embeddability, and by setting the thickness to be equal to or lower than the upper limit value, it is possible to suppress an increase in the amount of spots of the insulating layer 4a Reliability can be maintained.
- the first covering layer 5a laminated on the upper surface of the insulating layer 4a is preferably made of a resin material.
- the resin material include polyester resins, polyimides, and liquid crystal polymers. Among these, polyimide is preferable. Thereby, heat resistance and flexibility can be improved.
- the thickness of the coating layer 5a is not particularly limited, but is preferably 5 to 50 ⁇ m, and particularly preferably 10 to 30 ⁇ m. By making the thickness of the coating layer 5a equal to or greater than the lower limit value, it becomes easy to maintain the strength of the resin layer within the practical range, and by making the thickness less than the upper limit value, slidability and flexibility are maximized. It becomes easy to make.
- the insulating layer 4a may be formed integrally with the first coating layer 5a as an adhesive layer of the first coating layer 5a.
- the first coating layer 5a is composed of a resin layer and an adhesive layer.
- the resin material constituting the resin layer for example, a polyester resin, polyimide, liquid crystal polymer, or the like is used similarly to the resin material constituting the first covering layer 5a. Among these, it is preferable to use polyimide. Thereby, heat resistance and flexibility can be improved.
- the material constituting the adhesive layer is, for example, an acrylic resin, an epoxy resin, or a polyimide resin, like the material constituting the insulating layer 4a functioning as the second insulator layer described above. Etc. can be used. Among these, an epoxy resin is preferable, and thereby heat resistance and flexibility can be improved.
- the conductive portion as the ground layer 6 disposed on the other surface (back surface) of the base substrate 2 is composed of a conductor made of a copper material, and the conductive portion is located at a position facing the signal wirings 3a and 3b. A number of holes formed in the parallelogram openings are formed. The specific configuration of the ground layer 6 will be described later in detail with reference to FIG.
- an insulating layer 4b as a third insulator layer is provided.
- the material constituting the insulating layer 4b include acrylic resins, epoxy resins, and polyimide resins. Among these, an epoxy resin is preferable. Thereby, heat resistance and flexibility can be improved.
- the material which comprises the insulating layer 4a which comprises the above-mentioned 2nd insulator layer, and the insulating layer 4b which comprises a 3rd insulator layer may be the same, or may differ.
- the thickness of the insulating layer 4b is not particularly limited, but is preferably 5 to 40 ⁇ m, and particularly preferably 10 to 30 ⁇ m. Similar to the insulating layer 4a already described, the thickness of the insulating layer 4b is set to be equal to or higher than the lower limit value, thereby suppressing deterioration of the embedding property of the circuit. An increase in the amount of protrusion can be suppressed, and the reliability of interlayer adhesion can be maintained. Moreover, the thickness of the insulating layer 4a constituting the second insulator layer and the thickness of the insulating layer 4b constituting the third insulator layer may be the same or different.
- the second coating layer 5b provided on the lower surface of the insulating layer 4b is preferably made of a resin material.
- the resin material include polyester resin, polyimide, liquid crystal polymer, and the like. Among these, polyimide is preferable. Thereby, heat resistance and flexibility can be improved. Further, the resin material constituting the first coating layer 5a and the resin material constituting the second coating layer 5b may be the same or different.
- the thickness of the second coating layer 5b is not particularly limited, but is preferably 5 to 50 ⁇ m, and particularly preferably 10 to 30 ⁇ m. As with the coating layer 5a already described, this makes it easy to maintain the strength of the resin layer within the practical range by setting the thickness of the coating layer 5b to be equal to or higher than the lower limit, and to be lower than the upper limit. This makes it easy to maximize slidability and flexibility.
- the insulating layer 4b may be formed integrally with the coating layer 5b as an adhesive layer for the second coating layer 5b.
- the second coating layer 5b is composed of a resin layer and an adhesive layer.
- the material constituting the resin layer include a polyester-based resin, a polyimide, a liquid crystal polymer, and the like, similarly to the resin material constituting the second coating layer 5b described above.
- polyimide is preferable, and heat resistance and flexibility can be improved by employing this.
- an acrylic resin, an epoxy resin, a polyimide resin, and the like can be cited as with the material constituting the second insulating layer 4b described above.
- epoxy resins are preferable, and heat resistance and flexibility can be improved by adopting them.
- FIG. 2 is a partially enlarged view of the configuration of the ground layer 6 described above. 2 shows a state in which the signal wirings 3a and 3b described above are superimposed on the ground layer 6 through the base substrate 2 in a state seen through from a direction orthogonal to the surface.
- the ground layer 6 is made of a conductor made of a copper material, and the position of the conductor facing the signal wirings 3a and 3b constitutes a mesh-like conductor portion 6B in which a large number of holes are formed. Yes.
- the hole in this embodiment is formed as a parallelogram (diamond) opening by intersecting a plurality of lines in two directions.
- the plurality of lines in the two directions are preferably inclined with respect to the signal wirings 3a and 3b within a range of 5 to 40 degrees.
- the longer diagonal line of the rhomboid opening has a mesh pattern that matches the wiring direction of the signal wirings 3a and 3b. Thereby, it is possible to prevent the characteristic impedance of the signal wirings 3a and 3b bent about 45 degrees in the middle as shown in FIG.
- the openings (opening areas) may have different sizes (opening areas).
- the openings A and B have the same opening area. Thereby, the characteristic impedance of the signal wirings 3a and 3b can be controlled with high accuracy.
- a solid electrode region 6A made of a copper material in which no hole is formed is formed outside the mesh conductor portion 6B facing the signal wirings 3a and 3b. That is, the outside of the mesh-like conductor portion 6B that greatly affects the control of the characteristic impedance of the signal wirings 3a and 3b is formed as a solid electrode region 6A.
- the relationship between the mesh-like conductor portion 6B facing the signal wirings 3a and 3b through the insulator layer made of the film-like base substrate 2 and the solid electrode region 6A formed outside the mesh-like conductor portion 6B is shown.
- 3 is a schematic cross-sectional view.
- the thickness t of the insulator layer 2 is 100 ⁇ m or less, and the entire laminated structure is applied to a very thin circuit board. Therefore, the signal wirings 3a and 3b and the solid electrode region are applied.
- the distance U from 6A dominates the degree of capacitive coupling between the two.
- the distance U between the signal wirings 3a and 3b and the solid electrode region 6A is in the range of 20t ⁇ U ⁇ 3t, more preferably 10t ⁇ U. It is desirable to set the range of ⁇ 3t.
- FIG. 4 shows a characteristic example in which the distance U (multiple of the interlayer thickness t) between the signal wirings 3a and 3b and the solid electrode region 6A is shown on the horizontal axis, and the characteristic impedance Zo of the signal wirings 3a and 3b is shown on the vertical axis. Is.
- the distance U between the signal wirings 3a and 3b and the solid electrode region 6A is preferably 20 t or less, and more preferably 10 t or less.
- the characteristic impedance of the signal wirings 3a and 3b can be adjusted, and the ground layer 6 can have a low value.
- the condition for securing the DC resistance value is satisfied.
- FIG. 5 shows a laminated structure of a circuit board according to the second embodiment of the present invention.
- parts that perform the same functions as those shown in FIG. 1 already described are denoted by the same reference numerals, and therefore detailed description thereof will be omitted as appropriate.
- the signal wirings 3a and 3b are configured on a film-like base substrate 2 and function as an insulator layer covering the signal wirings 3a and 3b on the base substrate 2.
- a ground layer 6 is laminated on the upper surface of the second insulating layer 4a, thereby forming a microstrip structure.
- ground layer 6 faces the signal wirings 3a and 3b through the insulating layer 4a as compared with the stacked structure shown in FIG. Also in this configuration, the same effect can be obtained by adopting the configuration of the ground layer 6 shown in FIG.
- FIG. 6 shows a laminated structure of a circuit board according to the third embodiment of the present invention. Also in FIG. 6, parts that perform the same functions as those shown in FIG. 1 already described are denoted by the same reference numerals, and therefore detailed description thereof is omitted.
- signal wirings 3 a and 3 b are laminated on one surface of a film-like base substrate 2 that functions as an insulator layer, and a first ground layer 6 a is disposed on the other surface of the base substrate 2.
- a second ground layer 6b is laminated via a second insulator layer 4a covering the signal wirings 3a and 3b on the base substrate.
- the two ground layers 6a and 6b each have a signal via the film-like base material 2 and the insulating layer 4a that function as insulator layers. It is configured to face the wiring 3.
- the mesh-shaped conductor part 6B in embodiment described above is made into the structure which arranged many rhombus opening as shown in FIG. 2, this opening is not restricted to the above-mentioned specific shape. For example, it can be formed by arranging openings having a circular shape or other shapes.
- ground layer in the above-described embodiment may be configured to be applied with a reference potential of the circuit, and the operation power supply of each device may be superimposed. Therefore, the potential applied to the ground layer is not particularly limited.
- the circuit board according to the present invention can be used for a printed wiring board, a flexible printed wiring board, a multilayer flexible printed wiring board, and the like, and can be suitably used particularly for a circuit board on which a device operating in a high frequency band is mounted.
- Circuit board 2 Base substrate (insulator layer) 3a, 3b Signal wiring 4a, 4b Insulating layer 5a, 5b Cover layer 6, 6a, 6b Ground layer 6A Solid electrode region 6B Mesh conductor
Abstract
Disclosed is a circuit board having a strip structure or a microstrip structure wherein a ground layer (6) and signal lines (3a, 3b) are disposed with an insulator layer (2) interposed between the ground layer (6) and the signal lines (3a, 3b). A conductive part forming the ground layer has a mesh-shaped conductor section (6B) in which a large number of holes are formed in positions facing the signal lines, and thereby the characteristic impedances of the signal lines (3a, 3b) are adjusted. A solid electrode region (6A) in which no hole is formed is formed outside the mesh-shaped conductor section (6B). With this, the DC resistance of the ground layer (6) is prevented from increasing. If the thickness of the insulator layer (2) is t, the distance U between the signal lines and the solid electrode region is set in the range of 20t≥U≥3t.
Description
この発明は、グランド層と前記グランド層に対して絶縁体層を介して信号配線を配設した回路基板に関する。
The present invention relates to a ground layer and a circuit board in which signal wirings are arranged with respect to the ground layer via an insulator layer.
例えば高周波帯で動作するディバイスを実装する回路基板は、信号の反射や波形歪みの発生を抑えるために信号伝送路の特性インピーダンス(以下、Zoとも称する。)を、前記ディバイスの入出力インピーダンスに整合させる必要がある。
前記した信号伝送路の特性インピーダンスを整合させるためには、適切なパターン幅の信号伝送路(ストリップライン)に適切な厚さの絶縁層を挟んでグランド層を対峙させるストリップ構造またはマイクロストリップ構造が採用されている。 For example, in a circuit board on which a device operating in a high frequency band is mounted, the characteristic impedance (hereinafter also referred to as Zo) of the signal transmission path is matched to the input / output impedance of the device in order to suppress signal reflection and waveform distortion. It is necessary to let
In order to match the characteristic impedance of the signal transmission path described above, a strip structure or a microstrip structure in which a ground layer is opposed to a signal transmission path (strip line) having an appropriate pattern width with an insulating layer having an appropriate thickness interposed therebetween is used. It has been adopted.
前記した信号伝送路の特性インピーダンスを整合させるためには、適切なパターン幅の信号伝送路(ストリップライン)に適切な厚さの絶縁層を挟んでグランド層を対峙させるストリップ構造またはマイクロストリップ構造が採用されている。 For example, in a circuit board on which a device operating in a high frequency band is mounted, the characteristic impedance (hereinafter also referred to as Zo) of the signal transmission path is matched to the input / output impedance of the device in order to suppress signal reflection and waveform distortion. It is necessary to let
In order to match the characteristic impedance of the signal transmission path described above, a strip structure or a microstrip structure in which a ground layer is opposed to a signal transmission path (strip line) having an appropriate pattern width with an insulating layer having an appropriate thickness interposed therebetween is used. It has been adopted.
前記した回路基板構造における前記グランド層は、信号伝送路の特性インピーダンスを規定する電気的な基準面となる。そして、一般に特性インピーダンスはシングルエンドで50Ω前後に、差動伝送で100Ω前後に選択される場合が多い。
一方、前記した回路基板における特性インピーダンスは、信号伝送路の単位長さあたりのリアクタンスLと、前記信号伝送路とグランド層との間における単位面積あたりの静電容量Cの比(リアクタンスL/静電容量C)の平方根で近似される値となる。 The ground layer in the circuit board structure described above serves as an electrical reference plane that defines the characteristic impedance of the signal transmission path. In general, the characteristic impedance is often selected to be around 50Ω for single end and around 100Ω for differential transmission.
On the other hand, the characteristic impedance of the circuit board is the ratio of the reactance L per unit length of the signal transmission path and the capacitance C per unit area between the signal transmission path and the ground layer (reactance L / static It is a value approximated by the square root of the capacitance C).
一方、前記した回路基板における特性インピーダンスは、信号伝送路の単位長さあたりのリアクタンスLと、前記信号伝送路とグランド層との間における単位面積あたりの静電容量Cの比(リアクタンスL/静電容量C)の平方根で近似される値となる。 The ground layer in the circuit board structure described above serves as an electrical reference plane that defines the characteristic impedance of the signal transmission path. In general, the characteristic impedance is often selected to be around 50Ω for single end and around 100Ω for differential transmission.
On the other hand, the characteristic impedance of the circuit board is the ratio of the reactance L per unit length of the signal transmission path and the capacitance C per unit area between the signal transmission path and the ground layer (reactance L / static It is a value approximated by the square root of the capacitance C).
ところで、近年においては前記したディバイスを実装する回路基板として、薄いリジッド基板やフレキシブル回路基板が多用されており、このような回路基板を採用した場合においては、当然ながら前記グランド層に対する信号伝送路の層間が狭く(薄く)、両者間における静電容量Cの値が前記層間の寸法にほぼ反比例して上昇する。
したがって、前記した薄い多層構造の回路基板において、所望の前記Zoを得ようとするには、従来の層間が厚い回路基板に比べて前記信号伝送路(以下、信号配線とも言う。)の幅を狭く(細く)形成することで、前記静電容量Cの上昇を抑える手段を採用せざるを得ない。 By the way, in recent years, thin rigid boards and flexible circuit boards are frequently used as circuit boards for mounting the above-described devices. When such circuit boards are adopted, of course, the signal transmission path for the ground layer is naturally used. The interlayer is narrow (thin), and the value of the capacitance C between them increases almost in inverse proportion to the dimension between the layers.
Therefore, in order to obtain the desired Zo in the thin multilayer circuit board, the width of the signal transmission path (hereinafter also referred to as signal wiring) is larger than that of a conventional circuit board having a thick interlayer. By forming it narrow (narrow), it is necessary to adopt means for suppressing the increase in the capacitance C.
したがって、前記した薄い多層構造の回路基板において、所望の前記Zoを得ようとするには、従来の層間が厚い回路基板に比べて前記信号伝送路(以下、信号配線とも言う。)の幅を狭く(細く)形成することで、前記静電容量Cの上昇を抑える手段を採用せざるを得ない。 By the way, in recent years, thin rigid boards and flexible circuit boards are frequently used as circuit boards for mounting the above-described devices. When such circuit boards are adopted, of course, the signal transmission path for the ground layer is naturally used. The interlayer is narrow (thin), and the value of the capacitance C between them increases almost in inverse proportion to the dimension between the layers.
Therefore, in order to obtain the desired Zo in the thin multilayer circuit board, the width of the signal transmission path (hereinafter also referred to as signal wiring) is larger than that of a conventional circuit board having a thick interlayer. By forming it narrow (narrow), it is necessary to adopt means for suppressing the increase in the capacitance C.
このように所望のZoを得るために、信号配線を細く形成しようとする場合においては、信号配線の加工が困難なほどに細くせざるを得ない場合が発生する。また、たとえ信号配線の加工が可能であっても、信号配線が細いほど回路加工精度および線幅ばらつきの比率が高まり、これに伴ってZoのばらつきが増大する。
In this way, in order to obtain a desired Zo, when the signal wiring is to be formed thin, there is a case where the signal wiring has to be made so thin that it is difficult to process. Even if signal wiring can be processed, the thinner the signal wiring, the higher the ratio of circuit processing accuracy and line width variation, and the Zo variation increases accordingly.
このために、前記Zoの変化が大きな信号配線部分において、信号の反射や波形歪みを発生させるという問題を招来させる。さらに、信号配線の配線抵抗値が高くなるために、これに供給される信号周波数が高いほど、伝送特性の悪化の要因になる等の問題を抱えることになる。
For this reason, there arises a problem that signal reflection and waveform distortion occur in the signal wiring portion where the change of Zo is large. Furthermore, since the wiring resistance value of the signal wiring is increased, there is a problem that the higher the signal frequency supplied to the signal wiring, the worse the transmission characteristics.
そこで、前記した技術的な課題を解決するために、いわゆるベタ電極層として形成される前記グランド層をメッシュ状に銅抜きして、単位面積あたりのグランド層と信号配線との対向面積を実質的に小さくさせることで、前記信号配線の幅を確保する提案がなされている。これは次に示す先行技術文献に開示されている。
Therefore, in order to solve the above-described technical problem, the ground layer formed as a so-called solid electrode layer is removed in a mesh shape so that the opposing area between the ground layer and the signal wiring per unit area is substantially reduced. Proposals have been made to ensure the width of the signal wiring by making it smaller. This is disclosed in the following prior art documents.
図7は、前記した先行技術文献に示された回路基板の構成例を示したものであり、これは信号配線の方向が途中で、45度程度屈曲される場合の例を示している。すなわち図7は、グランド層6に平行四辺形状の開口を規則正しく形成したメッシュパターンに対して、互いに平行状態に配列された例えば差動伝送が行われる信号配線3a,3bが重畳された状態を、回路基板面に直交する方向から透視した状態で示している。
FIG. 7 shows a configuration example of the circuit board shown in the above-mentioned prior art document. This shows an example in which the direction of the signal wiring is bent about 45 degrees in the middle. That is, FIG. 7 shows a state in which, for example, signal wirings 3a and 3b for performing differential transmission arranged in parallel to each other are superimposed on a mesh pattern in which parallelogram-shaped openings are regularly formed in the ground layer 6. It is shown in a state seen through from a direction orthogonal to the circuit board surface.
図7に示す例は、交差する二方向の各線によりグランド層6に多数の平行四辺形状(菱形)のメッシュを開口させたものである。そして、符号Aで示す図の下半部における信号配線3a,3bに対するグランド層6側における二方向の線の交差角度と、符号Bで示す図の上半部における信号配線3a,3bに対するグランド層6側における二方向の線の交差角度が略同一となるように構成されている。
これにより、途中で屈曲する信号配線3a,3bの特性インピーダンスが、領域AおよびBにおいて、大きく変化するのを防止させることができる。 In the example shown in FIG. 7, a large number of parallelogram (diamond) meshes are opened in theground layer 6 by lines intersecting in two directions. Then, the crossing angle of the lines in the two directions on the ground layer 6 side with respect to the signal wirings 3a and 3b in the lower half part of the diagram indicated by the symbol A, and the ground layer for the signal wirings 3a and 3b in the upper half part of the diagram indicated by the symbol B The crossing angles of the two-direction lines on the 6 side are configured to be substantially the same.
Thereby, it is possible to prevent the characteristic impedance of thesignal wirings 3a and 3b bent in the middle from changing greatly in the regions A and B.
これにより、途中で屈曲する信号配線3a,3bの特性インピーダンスが、領域AおよびBにおいて、大きく変化するのを防止させることができる。 In the example shown in FIG. 7, a large number of parallelogram (diamond) meshes are opened in the
Thereby, it is possible to prevent the characteristic impedance of the
ところで、前記したようにグランド層の全面に開口を形成して、これに対峙する信号配線の特性インピーダンスを調整するように構成した場合、グランド層の全面に導体を施した場合(ベタ電極)に比較して、グランド層の直流抵抗値が増大することになる。
このために、例えばアースポイントから離れたグランド層の一部は高周波信号を受けて励起され、信号配線は高周波信号によるスプリアス妨害を受ける、もしくは信号配線を流れる高周波信号の漏洩の度合いが激しくなる等の問題を招く。 By the way, as described above, when the opening is formed on the entire surface of the ground layer and the characteristic impedance of the signal wiring opposed thereto is adjusted, the conductor is applied to the entire surface of the ground layer (solid electrode). In comparison, the DC resistance value of the ground layer increases.
For this reason, for example, a part of the ground layer away from the earth point is excited by receiving a high-frequency signal, the signal wiring is subject to spurious interference due to the high-frequency signal, or the leakage of the high-frequency signal flowing through the signal wiring becomes severe. Invite problems.
このために、例えばアースポイントから離れたグランド層の一部は高周波信号を受けて励起され、信号配線は高周波信号によるスプリアス妨害を受ける、もしくは信号配線を流れる高周波信号の漏洩の度合いが激しくなる等の問題を招く。 By the way, as described above, when the opening is formed on the entire surface of the ground layer and the characteristic impedance of the signal wiring opposed thereto is adjusted, the conductor is applied to the entire surface of the ground layer (solid electrode). In comparison, the DC resistance value of the ground layer increases.
For this reason, for example, a part of the ground layer away from the earth point is excited by receiving a high-frequency signal, the signal wiring is subject to spurious interference due to the high-frequency signal, or the leakage of the high-frequency signal flowing through the signal wiring becomes severe. Invite problems.
この発明は、前記した技術的な問題点に着目してなされたものであり、信号配線の特性インピーダンスの制御を十分に果たすことができると共に、グランド層の抵抗値の増大を抑制し、前記したスプリアス妨害等の対策も十分に発揮することができる回路基板を提供することを課題とするものである。
The present invention has been made by paying attention to the technical problems described above, and can sufficiently control the characteristic impedance of the signal wiring and suppress the increase in the resistance value of the ground layer. It is an object of the present invention to provide a circuit board that can sufficiently exhibit countermeasures such as spurious interference.
前記した課題を解決するためになされたこの発明にかかる回路基板は、グランド層と前記グランド層に対して絶縁体層を介して信号配線を配設し、前記グランド層と信号配線間の容量結合を制御することで、前記信号配線の特性インピーダンスの制御が成される回路基板であって、前記グランド層を形成する導電部には、前記信号配線に対峙する位置に多数の抜き孔を施したメッシュ状導体部が配置されることで、前記グランド層と信号配線間の容量結合を制御するように構成され、かつ前記メッシュ状導体部の外側には、抜き孔が施されないベタ電極領域が形成されていることを特徴とする。
The circuit board according to the present invention, which has been made to solve the above-described problems, includes a ground layer and a signal wiring disposed through an insulator layer with respect to the ground layer, and capacitive coupling between the ground layer and the signal wiring. Is a circuit board in which the characteristic impedance of the signal wiring is controlled, and the conductive portion forming the ground layer is provided with a number of holes at positions facing the signal wiring. By arranging the mesh-like conductor part, it is configured to control the capacitive coupling between the ground layer and the signal wiring, and a solid electrode region not formed with a hole is formed outside the mesh-like conductor part. It is characterized by being.
この場合、前記絶縁体層の厚さをtとした時、前記信号配線とベタ電極領域との距離Uが、20t≧U≧3tの範囲に設定されていることが望ましい。これは前記絶縁体層が、100μm以下の厚さになされる薄物の回路基板において、その効果が顕著に発揮し得る。
In this case, it is preferable that the distance U between the signal wiring and the solid electrode region is set in a range of 20t ≧ U ≧ 3t, where t is the thickness of the insulator layer. This effect can be exhibited remarkably in a thin circuit board in which the insulator layer has a thickness of 100 μm or less.
そして、前記メッシュ状導体部に形成される多数の前記抜き孔は、二方向の複数の各線が交差して平行四辺形の開口が施された形態に成される。
The plurality of holes formed in the mesh-like conductor portion are formed in a shape in which a plurality of lines in two directions intersect to form a parallelogram opening.
また、前記した回路基板を実現させる1つの好ましい形態においては、前記絶縁体層は、一方の面に前記信号配線を積層すると共に、他方の面に前記グランド層を配置した構成にされる。
Further, in one preferable embodiment for realizing the circuit board, the insulator layer is configured such that the signal wiring is laminated on one surface and the ground layer is disposed on the other surface.
また、他の1つの好ましい形態においては、前記信号配線は前記絶縁体層上に構成され、前記絶縁体層上の信号配線を覆う第2絶縁体層を介して前記グランド層が積層された構成にされる。
In another preferred embodiment, the signal wiring is formed on the insulator layer, and the ground layer is stacked via a second insulator layer covering the signal wiring on the insulator layer. To be.
さらに、他の1つの好ましい形態においては、前記絶縁体層は、一方の面に前記信号配線を積層すると共に、他方の面に前記グランド層を配置し、かつ前記絶縁体層上の信号配線を覆う第2絶縁体層を介して第2グランド層が積層された構成にされる。
そして、前記絶縁体層としては、好ましくはフィルム状ベース基材を用いた構成にされる。 Furthermore, in another preferred embodiment, the insulator layer has the signal wiring laminated on one surface, the ground layer is disposed on the other surface, and the signal wiring on the insulator layer is arranged. The second ground layer is stacked via the covering second insulator layer.
The insulator layer is preferably configured using a film-like base substrate.
そして、前記絶縁体層としては、好ましくはフィルム状ベース基材を用いた構成にされる。 Furthermore, in another preferred embodiment, the insulator layer has the signal wiring laminated on one surface, the ground layer is disposed on the other surface, and the signal wiring on the insulator layer is arranged. The second ground layer is stacked via the covering second insulator layer.
The insulator layer is preferably configured using a film-like base substrate.
前記した回路基板によれば、信号配線に対峙する位置におけるグランド層を構成する導電部には、多数の抜き孔が形成されたメッシュ状導体部にされることで、これに対峙する信号配線の特性インピーダンスを調整することができる。
そして、前記信号配線から離れた位置における前記導電部は抜き孔が形成されないベタ電極領域になされるので、このベタ電極がグランド層の直流抵抗の上昇を抑え、前記したスプリアス妨害等の対策を効果的に発揮させることが可能となる。 According to the circuit board described above, the conductive portion constituting the ground layer at the position facing the signal wiring is formed into a mesh-shaped conductor portion in which a large number of holes are formed, so that the signal wiring facing the signal wiring The characteristic impedance can be adjusted.
And since the said conductive part in the position away from the said signal wiring is made into the solid electrode area | region where a punch hole is not formed, this solid electrode suppresses the raise of the direct current | flow resistance of a ground layer, and measures, such as the above-mentioned spurious interference, are effective. It is possible to demonstrate it.
そして、前記信号配線から離れた位置における前記導電部は抜き孔が形成されないベタ電極領域になされるので、このベタ電極がグランド層の直流抵抗の上昇を抑え、前記したスプリアス妨害等の対策を効果的に発揮させることが可能となる。 According to the circuit board described above, the conductive portion constituting the ground layer at the position facing the signal wiring is formed into a mesh-shaped conductor portion in which a large number of holes are formed, so that the signal wiring facing the signal wiring The characteristic impedance can be adjusted.
And since the said conductive part in the position away from the said signal wiring is made into the solid electrode area | region where a punch hole is not formed, this solid electrode suppresses the raise of the direct current | flow resistance of a ground layer, and measures, such as the above-mentioned spurious interference, are effective. It is possible to demonstrate it.
この場合、信号配線とグランド層とを隔てる絶縁体層の厚さtが、両者の容量結合の度合いを支配することになり、前記絶縁体層の厚さtをパラメータとした時、前記信号配線とベタ電極領域との距離Uは、20t≧U≧3tの範囲に設定されることで、前記した信号配線の特性インピーダンスの調整、ならびにグランド層として低い値の直流抵抗値を確保する条件を満足するものとなる。
In this case, the thickness t of the insulator layer separating the signal wiring and the ground layer dominates the degree of capacitive coupling between them, and when the thickness t of the insulator layer is used as a parameter, the signal wiring Is set to a range of 20t ≧ U ≧ 3t, thereby satisfying the condition for adjusting the characteristic impedance of the signal wiring and securing a low DC resistance value as a ground layer. To be.
前記した範囲は、信号配線とグランド層とを隔てる絶縁体層の厚さtが、100μm以下である全体として薄く形成された回路基板に適用されることで、より好ましい結果を得ることができる。
The above range can be applied to a circuit board that is thinly formed as a whole with the thickness t of the insulator layer separating the signal wiring and the ground layer being 100 μm or less, whereby a more preferable result can be obtained.
そして前記絶縁体層として、フィルム状ベース基材を用いることによりフレキシブル性に優れた回路基板を得ることができ、ベース基材に例えばポリイミドを用いた場合においては、耐熱性および機械特性にも優れたフレキシブル回路基板を提供することができる。
As the insulator layer, a circuit board having excellent flexibility can be obtained by using a film-like base substrate. When, for example, polyimide is used for the base substrate, heat resistance and mechanical properties are also excellent. A flexible circuit board can be provided.
以下、この発明にかかる回路基板について、図に示す実施の形態に基づいて説明する。図1は、その第1の実施の形態を示した回路基板の積層構造を示すものである。図1に示す回路基板1は、グランド層とこのグランド層に対して絶縁体層を介して信号配線を配設したマイクロストリップ構造を構成するものであり、この実施の形態においては前記絶縁体層として、フィルム状のベース基材2が採用されている。
Hereinafter, a circuit board according to the present invention will be described based on the embodiments shown in the drawings. FIG. 1 shows a laminated structure of a circuit board showing the first embodiment. A circuit board 1 shown in FIG. 1 constitutes a microstrip structure in which a signal wiring is arranged with respect to a ground layer and an insulating layer with respect to the ground layer. In this embodiment, the insulating layer As shown, a film-like base substrate 2 is employed.
そして、ベース基材2の一方の面(図1における上側)には、例えば差動伝送される信号配線3a,3bが形成され、この信号配線3a,3bの上面(図1における上側)には第2の絶縁体層として機能する絶縁層4aが積層されている。また、絶縁層4aのさらに上面には第1の被覆層5aが設けられている。
一方、前記ベース基材2の他方の面(図1における下側)にはグランド層6が形成され、このグランド層6のさらに下面には第3の絶縁体層として機能する絶縁層4bが、さらにその下面には第2の被覆層5bが形成されている。 For example,signal wirings 3a and 3b for differential transmission are formed on one surface (upper side in FIG. 1) of the base substrate 2, and the upper surfaces (upper side in FIG. 1) of the signal wirings 3a and 3b are formed. An insulating layer 4a functioning as a second insulator layer is stacked. A first covering layer 5a is provided on the upper surface of the insulating layer 4a.
On the other hand, aground layer 6 is formed on the other surface (lower side in FIG. 1) of the base substrate 2, and an insulating layer 4b functioning as a third insulator layer is formed on the lower surface of the ground layer 6, Further, a second coating layer 5b is formed on the lower surface.
一方、前記ベース基材2の他方の面(図1における下側)にはグランド層6が形成され、このグランド層6のさらに下面には第3の絶縁体層として機能する絶縁層4bが、さらにその下面には第2の被覆層5bが形成されている。 For example,
On the other hand, a
マイクロストリップ構造を構成する中央の絶縁体層として機能する前記ベース基材2は、回路基板1のコアとなる機能も有している。前記ベース基材2の素材としては、樹脂フィルム、繊維基材等を挙げることができる。
The base substrate 2 that functions as a central insulator layer constituting the microstrip structure also has a function as a core of the circuit board 1. Examples of the material of the base substrate 2 include a resin film and a fiber substrate.
前記樹脂フィルムを構成する素材としては、例えばポリイミド樹脂、ポリアミド樹脂、ポリアミドイミド樹脂等のポリイミド樹脂、エポキシ樹脂等の熱硬化性樹脂や液晶ポリマーなどの熱可塑性樹脂等が挙げられる。
これらの中でもポリイミド樹脂または液晶ポリマーが好ましい。例えばポリイミド樹脂の場合は、耐熱性や機械特性に優れ、かつ入手するのが容易である。また、液晶ポリマーの場合は、その比誘電率の低さにより高速信号伝送用途に好適であり、かつ吸湿性の低さにより寸法安定性等にも優れる。 Examples of the material constituting the resin film include polyimide resins such as polyimide resins, polyamide resins, and polyamideimide resins, thermosetting resins such as epoxy resins, and thermoplastic resins such as liquid crystal polymers.
Among these, a polyimide resin or a liquid crystal polymer is preferable. For example, in the case of polyimide resin, it is excellent in heat resistance and mechanical properties and is easy to obtain. In the case of a liquid crystal polymer, it is suitable for high-speed signal transmission due to its low relative dielectric constant, and it has excellent dimensional stability due to its low hygroscopicity.
これらの中でもポリイミド樹脂または液晶ポリマーが好ましい。例えばポリイミド樹脂の場合は、耐熱性や機械特性に優れ、かつ入手するのが容易である。また、液晶ポリマーの場合は、その比誘電率の低さにより高速信号伝送用途に好適であり、かつ吸湿性の低さにより寸法安定性等にも優れる。 Examples of the material constituting the resin film include polyimide resins such as polyimide resins, polyamide resins, and polyamideimide resins, thermosetting resins such as epoxy resins, and thermoplastic resins such as liquid crystal polymers.
Among these, a polyimide resin or a liquid crystal polymer is preferable. For example, in the case of polyimide resin, it is excellent in heat resistance and mechanical properties and is easy to obtain. In the case of a liquid crystal polymer, it is suitable for high-speed signal transmission due to its low relative dielectric constant, and it has excellent dimensional stability due to its low hygroscopicity.
また、絶縁体層に用いられる繊維基材としては、例えばガラス繊布、ガラス不繊布等のガラス繊維基材、あるいはガラス以外の無機化合物を成分とする繊布又は不繊布等の無機繊維基材、芳香族ポリアミド樹脂、ポリアミド樹脂、芳香族ポリエステル樹脂、ポリエステル樹脂、ポリイミド樹脂、フッ素樹脂等の有機繊維で構成される有機繊維基材等が挙げられる。これら基材の中でも強度、吸水率の点でガラス繊布に代表されるガラス繊維基材が好ましい。
Examples of the fiber base material used for the insulating layer include glass fiber base materials such as glass fiber cloth and glass non-fiber cloth, or inorganic fiber base materials such as fiber cloth and non-fiber cloth containing inorganic compounds other than glass, aromatic And organic fiber base materials composed of organic fibers such as aromatic polyamide resins, polyamide resins, aromatic polyester resins, polyester resins, polyimide resins, and fluororesins. Among these base materials, glass fiber base materials represented by glass fiber fabric are preferable in terms of strength and water absorption.
前記絶縁体層に繊維基材を用いる場合においては、好ましくは前記繊維基材に樹脂を含浸させた状態で利用される。前記繊維基材に含浸される樹脂としては、好ましくはエポキシ樹脂系、アクリル樹脂系などの熱硬化性樹脂が用いられ、これらの中でも耐熱性の面からエポキシ樹脂系が好ましい。
When a fiber base material is used for the insulator layer, it is preferably used in a state where the fiber base material is impregnated with a resin. As the resin impregnated in the fiber base material, a thermosetting resin such as an epoxy resin or an acrylic resin is preferably used, and among these, an epoxy resin is preferable from the viewpoint of heat resistance.
前記ベース基材2の厚さは、好ましくは1~100μmの範囲になされ、さらに好ましくは5~50μmの範囲、より好ましくは10~30μmの範囲になされる。
前記ベース基材2の厚さを前記下限値以上にすることで、信号線の線幅を加工限界以上にすることが容易となり、一方、前記厚さを上限値以下にすることで剛性が高くなり過ぎることを抑え、柔軟さというフレキシブル回路基板など薄物基板の特徴を保持できる。 The thickness of thebase substrate 2 is preferably in the range of 1 to 100 μm, more preferably in the range of 5 to 50 μm, and more preferably in the range of 10 to 30 μm.
By setting the thickness of thebase substrate 2 to be equal to or greater than the lower limit value, it becomes easy to make the signal line width equal to or greater than the processing limit. On the other hand, by setting the thickness to be equal to or less than the upper limit value, rigidity is high. It is possible to suppress the occurrence of excessive thickness and retain the characteristics of a thin substrate such as a flexible circuit board that is flexible.
前記ベース基材2の厚さを前記下限値以上にすることで、信号線の線幅を加工限界以上にすることが容易となり、一方、前記厚さを上限値以下にすることで剛性が高くなり過ぎることを抑え、柔軟さというフレキシブル回路基板など薄物基板の特徴を保持できる。 The thickness of the
By setting the thickness of the
前記ベース基材2の一方の面に配列された信号配線3a,3bはベース基材2に直接設けられても良いが、接着剤を介して設けられていてもよい。そして、各信号配線の端部もしくは適宜の中間部において、図示しない半導体ディバイス等の実装パッドに接合され、回路基板1として機能する。
The signal wirings 3a and 3b arranged on one surface of the base substrate 2 may be provided directly on the base substrate 2, or may be provided via an adhesive. Then, at the end portion of each signal wiring or an appropriate intermediate portion, it is bonded to a mounting pad such as a semiconductor device (not shown) and functions as the circuit board 1.
前記信号配線3a,3bを覆う絶縁層4aは、例えばアクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂、液晶ポリマー等が挙げられる。これらの中でもエポキシ系樹脂が好ましい。これにより、耐熱性と屈曲性を向上することができる。
一方、前記液晶ポリマーを採用した場合においては、比誘電率が低く高速信号伝送特性に優れた特質を生かすことができる。 Examples of the insulating layer 4a covering thesignal wirings 3a and 3b include acrylic resin, epoxy resin, polyimide resin, and liquid crystal polymer. Among these, an epoxy resin is preferable. Thereby, heat resistance and flexibility can be improved.
On the other hand, when the liquid crystal polymer is used, it is possible to take advantage of the characteristics of a low relative dielectric constant and excellent high-speed signal transmission characteristics.
一方、前記液晶ポリマーを採用した場合においては、比誘電率が低く高速信号伝送特性に優れた特質を生かすことができる。 Examples of the insulating layer 4a covering the
On the other hand, when the liquid crystal polymer is used, it is possible to take advantage of the characteristics of a low relative dielectric constant and excellent high-speed signal transmission characteristics.
前記絶縁層4aの厚さは、特に限定されないが、5~40μmであることが好ましく、特に10~30μmが好ましい。絶縁層4aの厚さを前記下限値以上にすることで、回路の埋め込み性低下を抑制し、前記上限値以下にすることで絶縁層4aのシミ出し量の増加を抑制し、かつ層間接着の信頼性を維持することができる。
The thickness of the insulating layer 4a is not particularly limited, but is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm. By making the thickness of the insulating layer 4a equal to or higher than the lower limit value, it is possible to suppress a decrease in circuit embeddability, and by setting the thickness to be equal to or lower than the upper limit value, it is possible to suppress an increase in the amount of spots of the insulating layer 4a Reliability can be maintained.
前記絶縁層4aの上面に積層された第1の被覆層5aは、樹脂材料で構成されていることが好ましい。この樹脂材料としては、例えばポリエステル系樹脂、ポリイミド、液晶ポリマー等が挙げられる。これらの中でもポリイミドが好ましい。これにより、耐熱性と屈曲性を向上させることができる。
前記被覆層5aの厚さは、特に限定されないが、5~50μmであることが好ましく、特に10~30μmが好ましい。被覆層5aの厚さを前記下限値以上にすることで、樹脂層の強度を実用範囲に維持することが容易となり、前記上限値以下にすることで摺動性や屈曲性を最大限に発揮させることが容易となる。 The first covering layer 5a laminated on the upper surface of the insulating layer 4a is preferably made of a resin material. Examples of the resin material include polyester resins, polyimides, and liquid crystal polymers. Among these, polyimide is preferable. Thereby, heat resistance and flexibility can be improved.
The thickness of the coating layer 5a is not particularly limited, but is preferably 5 to 50 μm, and particularly preferably 10 to 30 μm. By making the thickness of the coating layer 5a equal to or greater than the lower limit value, it becomes easy to maintain the strength of the resin layer within the practical range, and by making the thickness less than the upper limit value, slidability and flexibility are maximized. It becomes easy to make.
前記被覆層5aの厚さは、特に限定されないが、5~50μmであることが好ましく、特に10~30μmが好ましい。被覆層5aの厚さを前記下限値以上にすることで、樹脂層の強度を実用範囲に維持することが容易となり、前記上限値以下にすることで摺動性や屈曲性を最大限に発揮させることが容易となる。 The first covering layer 5a laminated on the upper surface of the insulating layer 4a is preferably made of a resin material. Examples of the resin material include polyester resins, polyimides, and liquid crystal polymers. Among these, polyimide is preferable. Thereby, heat resistance and flexibility can be improved.
The thickness of the coating layer 5a is not particularly limited, but is preferably 5 to 50 μm, and particularly preferably 10 to 30 μm. By making the thickness of the coating layer 5a equal to or greater than the lower limit value, it becomes easy to maintain the strength of the resin layer within the practical range, and by making the thickness less than the upper limit value, slidability and flexibility are maximized. It becomes easy to make.
なお、前記絶縁層4aは、第1の被覆層5aの接着剤層として第1の被覆層5aに一体に形成されていてもよい。
この場合、第1の被覆層5aは、樹脂層と、接着剤層とで構成されることになる。この場合、前記樹脂層を構成する樹脂材料は、前述した第1の被覆層5aを構成する樹脂材料と同様に、例えばポリエステル系樹脂、ポリイミド、液晶ポリマー等が使用される。これらの中でもポリイミドを使用することが好ましい。これにより、耐熱性と屈曲性を向上させることができる。 The insulating layer 4a may be formed integrally with the first coating layer 5a as an adhesive layer of the first coating layer 5a.
In this case, the first coating layer 5a is composed of a resin layer and an adhesive layer. In this case, as the resin material constituting the resin layer, for example, a polyester resin, polyimide, liquid crystal polymer, or the like is used similarly to the resin material constituting the first covering layer 5a. Among these, it is preferable to use polyimide. Thereby, heat resistance and flexibility can be improved.
この場合、第1の被覆層5aは、樹脂層と、接着剤層とで構成されることになる。この場合、前記樹脂層を構成する樹脂材料は、前述した第1の被覆層5aを構成する樹脂材料と同様に、例えばポリエステル系樹脂、ポリイミド、液晶ポリマー等が使用される。これらの中でもポリイミドを使用することが好ましい。これにより、耐熱性と屈曲性を向上させることができる。 The insulating layer 4a may be formed integrally with the first coating layer 5a as an adhesive layer of the first coating layer 5a.
In this case, the first coating layer 5a is composed of a resin layer and an adhesive layer. In this case, as the resin material constituting the resin layer, for example, a polyester resin, polyimide, liquid crystal polymer, or the like is used similarly to the resin material constituting the first covering layer 5a. Among these, it is preferable to use polyimide. Thereby, heat resistance and flexibility can be improved.
また、この場合、前記接着剤層を構成する材料としては、前述した第2の絶縁体層として機能する絶縁層4aを構成する材料と同様に、例えばアクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂等を使用することができる。これらの中でもエポキシ系樹脂が好ましく、これにより耐熱性と屈曲性を向上させることができる。
In this case, the material constituting the adhesive layer is, for example, an acrylic resin, an epoxy resin, or a polyimide resin, like the material constituting the insulating layer 4a functioning as the second insulator layer described above. Etc. can be used. Among these, an epoxy resin is preferable, and thereby heat resistance and flexibility can be improved.
前記ベース基材2の他方の面(裏面)に配置されたグランド層6としての導電部は、銅素材による導電体により構成され、この導電部には前記信号配線3a,3bに対峙する位置に、平行四辺形の開口になされた多数の抜き孔が形成されている。なお、このグランド層6の具体的な構成については、図2に基づいて後で詳細に説明する。
The conductive portion as the ground layer 6 disposed on the other surface (back surface) of the base substrate 2 is composed of a conductor made of a copper material, and the conductive portion is located at a position facing the signal wirings 3a and 3b. A number of holes formed in the parallelogram openings are formed. The specific configuration of the ground layer 6 will be described later in detail with reference to FIG.
前記グランド層6の下側面(図1における下側)には、第3の絶縁体層としての絶縁層4bが設けられている。この絶縁層4bを構成する材料としては、例えばアクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂等を挙げることができる。これらの中でもエポキシ系樹脂が好ましい。これにより、耐熱性と屈曲性を向上させることができる。
なお、前記した第2の絶縁体層を構成する絶縁層4aと第3の絶縁体層を構成する絶縁層4bを構成する材料は、同じであっても異なっていてもよい。 On the lower surface of the ground layer 6 (the lower side in FIG. 1), an insulating layer 4b as a third insulator layer is provided. Examples of the material constituting the insulating layer 4b include acrylic resins, epoxy resins, and polyimide resins. Among these, an epoxy resin is preferable. Thereby, heat resistance and flexibility can be improved.
In addition, the material which comprises the insulating layer 4a which comprises the above-mentioned 2nd insulator layer, and the insulating layer 4b which comprises a 3rd insulator layer may be the same, or may differ.
なお、前記した第2の絶縁体層を構成する絶縁層4aと第3の絶縁体層を構成する絶縁層4bを構成する材料は、同じであっても異なっていてもよい。 On the lower surface of the ground layer 6 (the lower side in FIG. 1), an insulating layer 4b as a third insulator layer is provided. Examples of the material constituting the insulating layer 4b include acrylic resins, epoxy resins, and polyimide resins. Among these, an epoxy resin is preferable. Thereby, heat resistance and flexibility can be improved.
In addition, the material which comprises the insulating layer 4a which comprises the above-mentioned 2nd insulator layer, and the insulating layer 4b which comprises a 3rd insulator layer may be the same, or may differ.
前記絶縁層4bの厚さは、特に限定されないが、5~40μmであることが好ましく、特に10~30μmが好ましい。
これはすでに説明した絶縁層4aと同様に、絶縁層4bの厚さを前記下限値以上にすることで、回路の埋め込み性低下を抑制し、前記上限値以下にすることで絶縁層4bのシミ出し量の増加を抑制し、かつ層間接着の信頼性を維持することができる。
また、第2の絶縁体層を構成する絶縁層4aの厚さと、第3の絶縁体層を構成する絶縁層4bの厚さとは、同じであっても異なっていても良い。 The thickness of the insulating layer 4b is not particularly limited, but is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm.
Similar to the insulating layer 4a already described, the thickness of the insulating layer 4b is set to be equal to or higher than the lower limit value, thereby suppressing deterioration of the embedding property of the circuit. An increase in the amount of protrusion can be suppressed, and the reliability of interlayer adhesion can be maintained.
Moreover, the thickness of the insulating layer 4a constituting the second insulator layer and the thickness of the insulating layer 4b constituting the third insulator layer may be the same or different.
これはすでに説明した絶縁層4aと同様に、絶縁層4bの厚さを前記下限値以上にすることで、回路の埋め込み性低下を抑制し、前記上限値以下にすることで絶縁層4bのシミ出し量の増加を抑制し、かつ層間接着の信頼性を維持することができる。
また、第2の絶縁体層を構成する絶縁層4aの厚さと、第3の絶縁体層を構成する絶縁層4bの厚さとは、同じであっても異なっていても良い。 The thickness of the insulating layer 4b is not particularly limited, but is preferably 5 to 40 μm, and particularly preferably 10 to 30 μm.
Similar to the insulating layer 4a already described, the thickness of the insulating layer 4b is set to be equal to or higher than the lower limit value, thereby suppressing deterioration of the embedding property of the circuit. An increase in the amount of protrusion can be suppressed, and the reliability of interlayer adhesion can be maintained.
Moreover, the thickness of the insulating layer 4a constituting the second insulator layer and the thickness of the insulating layer 4b constituting the third insulator layer may be the same or different.
前記絶縁層4bの下側面に設けられた第2の被覆層5bは、樹脂材料で構成されていることが好ましい。この樹脂材料をとしては、例えばポリエステル系樹脂、ポリイミド、液晶ポリマー等が挙げられる。これらの中でもポリイミドが好ましい。これにより、耐熱性と屈曲性を向上することができる。
また、第1の被覆層5aを構成する樹脂材料と、第2の被覆層5bとを構成する樹脂材料とは、同じであっても異なっていても良い。 The second coating layer 5b provided on the lower surface of the insulating layer 4b is preferably made of a resin material. Examples of the resin material include polyester resin, polyimide, liquid crystal polymer, and the like. Among these, polyimide is preferable. Thereby, heat resistance and flexibility can be improved.
Further, the resin material constituting the first coating layer 5a and the resin material constituting the second coating layer 5b may be the same or different.
また、第1の被覆層5aを構成する樹脂材料と、第2の被覆層5bとを構成する樹脂材料とは、同じであっても異なっていても良い。 The second coating layer 5b provided on the lower surface of the insulating layer 4b is preferably made of a resin material. Examples of the resin material include polyester resin, polyimide, liquid crystal polymer, and the like. Among these, polyimide is preferable. Thereby, heat resistance and flexibility can be improved.
Further, the resin material constituting the first coating layer 5a and the resin material constituting the second coating layer 5b may be the same or different.
前記第2の被覆層5bの厚さは、特に限定されないが、5~50μmであることが好ましく、特に10~30μmが好ましい。これはすでに説明した被覆層5aと同様に、被覆層5bの厚さを前記下限値以上にすることで、樹脂層の強度を実用範囲に維持することが容易となり、前記上限値以下にすることで摺動性や屈曲性を最大限に発揮させることが容易となる。
The thickness of the second coating layer 5b is not particularly limited, but is preferably 5 to 50 μm, and particularly preferably 10 to 30 μm. As with the coating layer 5a already described, this makes it easy to maintain the strength of the resin layer within the practical range by setting the thickness of the coating layer 5b to be equal to or higher than the lower limit, and to be lower than the upper limit. This makes it easy to maximize slidability and flexibility.
なお、前記絶縁層4bは、第2の被覆層5bの接着剤層として被覆層5bに一体に形成されていてもよい。この場合、第2の被覆層5bは、樹脂層と、接着剤層とで構成されることになる。
この場合、前記樹脂層を構成する材料としては、前述した第2の被覆層5bを構成する樹脂材料と同様に、例えばポリエステル系樹脂、ポリイミド、液晶ポリマー等を挙げることができる。これらの中でもポリイミドが好ましく、これを採用することで、耐熱性と屈曲性を向上させることができる。 The insulating layer 4b may be formed integrally with the coating layer 5b as an adhesive layer for the second coating layer 5b. In this case, the second coating layer 5b is composed of a resin layer and an adhesive layer.
In this case, examples of the material constituting the resin layer include a polyester-based resin, a polyimide, a liquid crystal polymer, and the like, similarly to the resin material constituting the second coating layer 5b described above. Among these, polyimide is preferable, and heat resistance and flexibility can be improved by employing this.
この場合、前記樹脂層を構成する材料としては、前述した第2の被覆層5bを構成する樹脂材料と同様に、例えばポリエステル系樹脂、ポリイミド、液晶ポリマー等を挙げることができる。これらの中でもポリイミドが好ましく、これを採用することで、耐熱性と屈曲性を向上させることができる。 The insulating layer 4b may be formed integrally with the coating layer 5b as an adhesive layer for the second coating layer 5b. In this case, the second coating layer 5b is composed of a resin layer and an adhesive layer.
In this case, examples of the material constituting the resin layer include a polyester-based resin, a polyimide, a liquid crystal polymer, and the like, similarly to the resin material constituting the second coating layer 5b described above. Among these, polyimide is preferable, and heat resistance and flexibility can be improved by employing this.
また、この場合、前記接着剤層を構成する材料としては、前述した第2の絶縁層4bを構成する材料と同様に、例えばアクリル系樹脂、エポキシ系樹脂、ポリイミド系樹脂等を挙げることができる。これらの中でもエポキシ系樹脂が好ましく、これを採用することで、耐熱性と屈曲性を向上させることができる。
Further, in this case, as the material constituting the adhesive layer, for example, an acrylic resin, an epoxy resin, a polyimide resin, and the like can be cited as with the material constituting the second insulating layer 4b described above. . Among these, epoxy resins are preferable, and heat resistance and flexibility can be improved by adopting them.
図2は前記したグランド層6の構成を、その一部を拡大して示したものである。なお、図2は前記した信号配線3a,3bがベース基材2を介してグランド層6の上に重畳された状態を、面に直交する方向から透視した状態で示している。
グランド層6は前記したとおり銅素材による導電体により構成され、この導電体における前記した信号配線3a,3bに対峙する位置は、多数の抜き孔が形成されたメッシュ状導体部6Bを構成している。 FIG. 2 is a partially enlarged view of the configuration of theground layer 6 described above. 2 shows a state in which the signal wirings 3a and 3b described above are superimposed on the ground layer 6 through the base substrate 2 in a state seen through from a direction orthogonal to the surface.
As described above, theground layer 6 is made of a conductor made of a copper material, and the position of the conductor facing the signal wirings 3a and 3b constitutes a mesh-like conductor portion 6B in which a large number of holes are formed. Yes.
グランド層6は前記したとおり銅素材による導電体により構成され、この導電体における前記した信号配線3a,3bに対峙する位置は、多数の抜き孔が形成されたメッシュ状導体部6Bを構成している。 FIG. 2 is a partially enlarged view of the configuration of the
As described above, the
すなわち、この実施の形態における前記抜き孔は、二方向の複数の各線が交差して平行四辺形(菱形)の開口になされている。この二方向の複数の各線は、信号配線3a,3bに対して5~40度の範囲でそれぞれ傾斜されていることが望ましい。加えて、前記菱形開口の長い方の対角線が、前記信号配線3a,3bの配線方向と一致するようなメッシュパターンになされている。
これにより、図2に示すように途中で45度程度屈曲する信号配線3a,3bの特性インピーダンスが、領域AおよびBにおいて大きく変化するのを防止させることができる。 That is, the hole in this embodiment is formed as a parallelogram (diamond) opening by intersecting a plurality of lines in two directions. The plurality of lines in the two directions are preferably inclined with respect to thesignal wirings 3a and 3b within a range of 5 to 40 degrees. In addition, the longer diagonal line of the rhomboid opening has a mesh pattern that matches the wiring direction of the signal wirings 3a and 3b.
Thereby, it is possible to prevent the characteristic impedance of thesignal wirings 3a and 3b bent about 45 degrees in the middle as shown in FIG.
これにより、図2に示すように途中で45度程度屈曲する信号配線3a,3bの特性インピーダンスが、領域AおよびBにおいて大きく変化するのを防止させることができる。 That is, the hole in this embodiment is formed as a parallelogram (diamond) opening by intersecting a plurality of lines in two directions. The plurality of lines in the two directions are preferably inclined with respect to the
Thereby, it is possible to prevent the characteristic impedance of the
なお、前記した各開口は、その大きさ(開口面積)が互いに異なるものであってもよいが、好ましくは、前記領域AおよびBにおいて、同じ大きさの開口面積になされる。これにより、信号配線3a,3bの特性インピーダンスを高精度に制御することができる。
The openings (opening areas) may have different sizes (opening areas). Preferably, the openings A and B have the same opening area. Thereby, the characteristic impedance of the signal wirings 3a and 3b can be controlled with high accuracy.
一方、前記信号配線3a,3bに対峙するメッシュ状導体部6Bの外側においては、抜き孔が形成されない銅素材によるベタ電極領域6Aになされている。
すなわち、信号配線3a,3bの特性インピーダンスの制御に大きく作用する前記したメッシュ状導体部6Bを除いて、その外側はベタ電極領域6Aになされている。 On the other hand, outside themesh conductor portion 6B facing the signal wirings 3a and 3b, a solid electrode region 6A made of a copper material in which no hole is formed is formed.
That is, the outside of the mesh-like conductor portion 6B that greatly affects the control of the characteristic impedance of the signal wirings 3a and 3b is formed as a solid electrode region 6A.
すなわち、信号配線3a,3bの特性インピーダンスの制御に大きく作用する前記したメッシュ状導体部6Bを除いて、その外側はベタ電極領域6Aになされている。 On the other hand, outside the
That is, the outside of the mesh-
前記したフィルム状ベース基材2による絶縁体層を介して信号配線3a,3bに対峙するメッシュ状導体部6B、およびメッシュ状導体部6Bの外側に形成されるベタ電極領域6Aとの関係を図3に模式的な断面図で示している。
この実施の形態においては、前記絶縁体層2の厚さtが100μm以下になされ、積層構造の全体がきわめて薄い回路基板に適用されるものであり、したがって前記信号配線3a,3bとベタ電極領域6Aとの距離Uが、両者の容量結合の度合いを支配することになる。 The relationship between the mesh-like conductor portion 6B facing the signal wirings 3a and 3b through the insulator layer made of the film-like base substrate 2 and the solid electrode region 6A formed outside the mesh-like conductor portion 6B is shown. 3 is a schematic cross-sectional view.
In this embodiment, the thickness t of theinsulator layer 2 is 100 μm or less, and the entire laminated structure is applied to a very thin circuit board. Therefore, the signal wirings 3a and 3b and the solid electrode region are applied. The distance U from 6A dominates the degree of capacitive coupling between the two.
この実施の形態においては、前記絶縁体層2の厚さtが100μm以下になされ、積層構造の全体がきわめて薄い回路基板に適用されるものであり、したがって前記信号配線3a,3bとベタ電極領域6Aとの距離Uが、両者の容量結合の度合いを支配することになる。 The relationship between the mesh-
In this embodiment, the thickness t of the
この場合、前記絶縁体層2の厚さtをパラメータとした時、前記信号配線3a,3bとベタ電極領域6Aとの距離Uは、20t≧U≧3tの範囲に、より好ましくは10t≧U≧3tの範囲に設定されることが望ましい。
In this case, when the thickness t of the insulator layer 2 is used as a parameter, the distance U between the signal wirings 3a and 3b and the solid electrode region 6A is in the range of 20t ≧ U ≧ 3t, more preferably 10t ≧ U. It is desirable to set the range of ≧ 3t.
図4は、信号配線3a,3bとベタ電極領域6Aとの距離U(層間厚みtの倍数)を横軸にし、信号配線3a,3bの特性インピーダンスZoを縦軸で示した特性例を示したものである。
この図4に示す特性例は、差動信号線3a,3bの各線幅L/線間距離S=100μm/100μになされ、層間厚みt=25μm、メッシュ状導体部6Bの銅(導体)残存率=30%の場合におけるものである。 FIG. 4 shows a characteristic example in which the distance U (multiple of the interlayer thickness t) between thesignal wirings 3a and 3b and the solid electrode region 6A is shown on the horizontal axis, and the characteristic impedance Zo of the signal wirings 3a and 3b is shown on the vertical axis. Is.
In the characteristic example shown in FIG. 4, each of thedifferential signal lines 3a and 3b has a line width L / interline distance S = 100 μm / 100 μm, an interlayer thickness t = 25 μm, and a copper (conductor) remaining rate of the mesh-like conductor portion 6B. = In the case of 30%.
この図4に示す特性例は、差動信号線3a,3bの各線幅L/線間距離S=100μm/100μになされ、層間厚みt=25μm、メッシュ状導体部6Bの銅(導体)残存率=30%の場合におけるものである。 FIG. 4 shows a characteristic example in which the distance U (multiple of the interlayer thickness t) between the
In the characteristic example shown in FIG. 4, each of the
すなわち、図4の特性線図に現れているように、前記信号配線3a,3bとベタ電極領域6Aとの距離Uが、3t未満になる場合には、信号配線に対するベタ電極領域の容量結合が急激に増大し、メッシュ状導体部6Bによる信号配線の適正なインピーダンス制御が不可能になる。
一方、前記信号配線3a,3bとベタ電極領域6Aとの距離Uが、3tを超える場合には信号配線に対するベタ電極領域の容量結合は急激に減少し、メッシュ状導体部6Bによる信号配線のインピーダンス制御の精度を向上させることができる。 That is, as shown in the characteristic diagram of FIG. 4, when the distance U between thesignal wirings 3a and 3b and the solid electrode region 6A is less than 3t, the capacitive coupling of the solid electrode region to the signal wiring is reduced. It increases rapidly, and proper impedance control of the signal wiring by the mesh-like conductor portion 6B becomes impossible.
On the other hand, when the distance U between thesignal wirings 3a and 3b and the solid electrode region 6A exceeds 3t, the capacitive coupling of the solid electrode region to the signal wiring is drastically reduced, and the impedance of the signal wiring by the mesh-like conductor portion 6B. The accuracy of control can be improved.
一方、前記信号配線3a,3bとベタ電極領域6Aとの距離Uが、3tを超える場合には信号配線に対するベタ電極領域の容量結合は急激に減少し、メッシュ状導体部6Bによる信号配線のインピーダンス制御の精度を向上させることができる。 That is, as shown in the characteristic diagram of FIG. 4, when the distance U between the
On the other hand, when the distance U between the
なお、層間厚みt=100μm以下の条件下において、同様の測定を試みたが、前記信号配線3a,3bとベタ電極領域6Aとの距離Uが、3t未満になる場合において、信号配線に対するベタ電極領域の容量結合が急激に増大し、信号配線の特性インピーダンスが低下することが検証されており、いずれにおいても図4に示す特性とほぼ同様の結果となることが認められている。
Although the same measurement was attempted under the condition that the interlayer thickness t = 100 μm or less, when the distance U between the signal wirings 3a and 3b and the solid electrode region 6A is less than 3t, the solid electrode with respect to the signal wiring It has been verified that the capacitive coupling of the region rapidly increases and the characteristic impedance of the signal wiring decreases, and it is recognized that the results are almost the same as the characteristics shown in FIG.
ところで、前記距離Uは、その値が大きいほど、ベタ電極領域6Aによる影響を少なくすることができるものの、反面メッシュ状導体部6Bの面積の増大に伴うグランド層の直流抵抗値の増加が、回路基板の高周波特性の悪化を招くことになる。 それ故、グランド層の直流抵抗値の増加に対処するには、信号配線3a,3bとベタ電極領域6Aとの距離Uは20t以下になされることが望ましく、より望ましくは10t以下の範囲になされる。
By the way, the larger the value of the distance U, the smaller the influence of the solid electrode region 6A, but the increase of the DC resistance value of the ground layer accompanying the increase of the area of the mesh-like conductor portion 6B The high frequency characteristics of the substrate will be deteriorated. Therefore, in order to cope with an increase in the DC resistance value of the ground layer, the distance U between the signal wirings 3a and 3b and the solid electrode region 6A is preferably 20 t or less, and more preferably 10 t or less. The
斯くして、前記信号配線3a,3bとベタ電極領域6Aとの距離Uを、前記した範囲に設定することで、信号配線3a,3bの特性インピーダンスの調整、ならびにグランド層6として、低い値の直流抵抗値を確保する条件を満足するものとなる。
Thus, by setting the distance U between the signal wirings 3a and 3b and the solid electrode region 6A within the above-described range, the characteristic impedance of the signal wirings 3a and 3b can be adjusted, and the ground layer 6 can have a low value. The condition for securing the DC resistance value is satisfied.
図5は、この発明の第2の実施形態にかかる回路基板の積層構造を示すものである。なお、この図5においてはすでに説明した図1に示した各部と同一機能を果たす部分を同一符号で示しており、したがってその詳細な説明は適宜省略する。
FIG. 5 shows a laminated structure of a circuit board according to the second embodiment of the present invention. In FIG. 5, parts that perform the same functions as those shown in FIG. 1 already described are denoted by the same reference numerals, and therefore detailed description thereof will be omitted as appropriate.
この図5に示す構成においては、前記信号配線3a,3bはフィルム状のベース基材2上に構成されると共に、前記ベース基材2上の信号配線3a,3bを覆う絶縁体層として機能する第2絶縁層4aを介して、その上面にグランド層6が積層されており、これによりマイクロストリップ構造を構成している。
In the configuration shown in FIG. 5, the signal wirings 3a and 3b are configured on a film-like base substrate 2 and function as an insulator layer covering the signal wirings 3a and 3b on the base substrate 2. A ground layer 6 is laminated on the upper surface of the second insulating layer 4a, thereby forming a microstrip structure.
図5に示す積層構成においては、図1に示した積層構成に比較すると、前記グランド層6が絶縁層4aを介して信号配線3a,3bに対峙するように構成されている。この構成においても、図2に示したグランド層6の構成を採用することで、同一の作用効果を得ることができる。
5 is configured such that the ground layer 6 faces the signal wirings 3a and 3b through the insulating layer 4a as compared with the stacked structure shown in FIG. Also in this configuration, the same effect can be obtained by adopting the configuration of the ground layer 6 shown in FIG.
図6は、この発明の第3の実施形態にかかる回路基板の積層構造を示すものである。なお、この図6においてもすでに説明した図1に示した各部と同一機能を果たす部分を同一符号で示しており、したがってその詳細な説明は省略する。
FIG. 6 shows a laminated structure of a circuit board according to the third embodiment of the present invention. Also in FIG. 6, parts that perform the same functions as those shown in FIG. 1 already described are denoted by the same reference numerals, and therefore detailed description thereof is omitted.
図6に示す構成においては、絶縁体層として機能するフィルム状ベース基材2の一方の面に信号配線3a,3bが積層され、ベース基材2の他方の面に第1グランド層6aを配置すると共に、前記ベース基材上の信号配線3a,3bを覆う第2絶縁体層4aを介して第2グランド層6bが積層されている。これにより、ストリップ構造を構成している。
In the configuration shown in FIG. 6, signal wirings 3 a and 3 b are laminated on one surface of a film-like base substrate 2 that functions as an insulator layer, and a first ground layer 6 a is disposed on the other surface of the base substrate 2. In addition, a second ground layer 6b is laminated via a second insulator layer 4a covering the signal wirings 3a and 3b on the base substrate. Thus, a strip structure is configured.
図6に示す積層構成においては、図1に示した積層構成に比較すると、2枚のグランド層6a,6bが絶縁体層として機能するフィルム状ベース基材2および絶縁層4aを介してそれぞれ信号配線3に対峙するように構成されている。
この構成における前記各グランド層6a,6bのそれぞれにおいて、図2に示したグランド層の構成を採用することで、同一の作用効果を得ることができる。 In the laminated structure shown in FIG. 6, in comparison with the laminated structure shown in FIG. 1, the two ground layers 6a and 6b each have a signal via the film-like base material 2 and the insulating layer 4a that function as insulator layers. It is configured to face the wiring 3.
By adopting the configuration of the ground layer shown in FIG. 2 in each of the ground layers 6a and 6b in this configuration, the same operational effects can be obtained.
この構成における前記各グランド層6a,6bのそれぞれにおいて、図2に示したグランド層の構成を採用することで、同一の作用効果を得ることができる。 In the laminated structure shown in FIG. 6, in comparison with the laminated structure shown in FIG. 1, the two ground layers 6a and 6b each have a signal via the film-
By adopting the configuration of the ground layer shown in FIG. 2 in each of the ground layers 6a and 6b in this configuration, the same operational effects can be obtained.
なお、以上説明した実施の形態におけるメッシュ状導体部6Bは、図2に示すように多数の菱形の開口を配列した構成にされているが、この開口は前記した特定の形状に限られるものではなく、例えば円形もしくはそれ以外の形状の開口部を配列することにより形成することもできる。
In addition, although the mesh-shaped conductor part 6B in embodiment described above is made into the structure which arranged many rhombus opening as shown in FIG. 2, this opening is not restricted to the above-mentioned specific shape. For example, it can be formed by arranging openings having a circular shape or other shapes.
また、前記した実施の形態におけるグランド層は、回路の基準電位が印加される構成にされる場合もあり、また各ディバイスの動作電源が重畳される場合もある。したがって、グランド層に印加される電位は特に限定されるものではない。
In addition, the ground layer in the above-described embodiment may be configured to be applied with a reference potential of the circuit, and the operation power supply of each device may be superimposed. Therefore, the potential applied to the ground layer is not particularly limited.
この発明による回路基板は、プリント配線板、フレキシブルプリント配線板、多層フレキシブルプリント配線板等に用いることができ、特に高周波帯で動作するディバイスを実装する回路基板に好適に採用することができる。
The circuit board according to the present invention can be used for a printed wiring board, a flexible printed wiring board, a multilayer flexible printed wiring board, and the like, and can be suitably used particularly for a circuit board on which a device operating in a high frequency band is mounted.
1 回路基板
2 ベース基材(絶縁体層)
3a,3b 信号配線
4a,4b 絶縁層
5a,5b 被覆層
6,6a,6b グランド層
6A ベタ電極領域
6B メッシュ状導体部
1Circuit board 2 Base substrate (insulator layer)
3a, 3b Signal wiring 4a, 4b Insulating layer 5a,5b Cover layer 6, 6a, 6b Ground layer 6A Solid electrode region 6B Mesh conductor
2 ベース基材(絶縁体層)
3a,3b 信号配線
4a,4b 絶縁層
5a,5b 被覆層
6,6a,6b グランド層
6A ベタ電極領域
6B メッシュ状導体部
1
3a, 3b Signal wiring 4a, 4b Insulating layer 5a,
Claims (8)
- グランド層と前記グランド層に対して絶縁体層を介して信号配線を配設し、前記グランド層と信号配線間の容量結合を制御することで、前記信号配線の特性インピーダンスの制御が成される回路基板であって、
前記グランド層を形成する導電部には、前記信号配線に対峙する位置に多数の抜き孔を施したメッシュ状導体部が配置されることで、前記グランド層と信号配線間の容量結合を制御するように構成され、
かつ前記メッシュ状導体部の外側には、抜き孔が施されないベタ電極領域が形成されていることを特徴とする回路基板。 The signal wiring is disposed via the insulator layer with respect to the ground layer and the ground layer, and the characteristic coupling of the signal wiring is controlled by controlling the capacitive coupling between the ground layer and the signal wiring. A circuit board,
The conductive portion forming the ground layer is provided with a mesh-like conductor portion provided with a large number of holes at positions facing the signal wiring, thereby controlling capacitive coupling between the ground layer and the signal wiring. Configured as
The circuit board is characterized in that a solid electrode region not formed with a hole is formed outside the mesh-like conductor portion. - 前記絶縁体層の厚さをtとした時、前記信号配線とベタ電極領域との距離Uが、20t≧U≧3tの範囲に設定されていることを特徴とする請求項1に記載された回路基板。 The distance U between the signal wiring and the solid electrode region is set in a range of 20t ≧ U ≧ 3t, where t is the thickness of the insulator layer. Circuit board.
- 前記絶縁体層は、100μm以下の厚さを有することを特徴とする請求項2に記載された回路基板。 3. The circuit board according to claim 2, wherein the insulator layer has a thickness of 100 μm or less.
- 前記メッシュ状導体部に形成される多数の前記抜き孔は、二方向の複数の各線が交差して平行四辺形の開口になされていることを特徴とする請求項1ないし請求項3のいずれか1項に記載された回路基板。 4. The plurality of holes formed in the mesh-shaped conductor portion are formed into parallelogram openings by intersecting a plurality of lines in two directions. 1. The circuit board described in item 1.
- 前記絶縁体層は、一方の面に前記信号配線を積層すると共に、他方の面に前記グランド層を配置したことを特徴とする請求項1ないし請求項3のいずれか1項に記載された回路基板。 4. The circuit according to claim 1, wherein the insulator layer is formed by laminating the signal wiring on one surface and arranging the ground layer on the other surface. 5. substrate.
- 前記信号配線は前記絶縁体層上に構成され、前記絶縁体層上の信号配線を覆う第2絶縁体層を介して前記グランド層が積層されていることを特徴とする請求項1ないし請求項3のいずれか1項に記載された回路基板。 The said signal wiring is comprised on the said insulator layer, The said ground layer is laminated | stacked through the 2nd insulator layer which covers the signal wiring on the said insulator layer. 4. The circuit board according to any one of 3 above.
- 前記絶縁体層は、一方の面に前記信号配線を積層すると共に、他方の面に前記グランド層を配置し、かつ前記絶縁体層上の信号配線を覆う第2絶縁体層を介して第2グランド層が積層されていることを特徴とする請求項1ないし請求項3のいずれか1項に記載された回路基板。 The insulator layer is formed by laminating the signal wiring on one surface, arranging the ground layer on the other surface, and secondly via a second insulator layer covering the signal wiring on the insulator layer. The circuit board according to any one of claims 1 to 3, wherein a ground layer is laminated.
- 前記絶縁体層は、フィルム状ベース基材により構成されていることを特徴とする請求項1ないし請求項3のいずれか1項に記載された回路基板。 The circuit board according to any one of claims 1 to 3, wherein the insulator layer is formed of a film-like base substrate.
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TWI492673B (en) | 2015-07-11 |
JP2010212438A (en) | 2010-09-24 |
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