JP2000299538A - Circuit board and method of manufacturing circuit board - Google Patents

Abstract

(57) [Problem] To be generated at a component mounting pad portion of a circuit board while maintaining connection reliability such as peel strength without changing a conventional manufacturing process and further increasing manufacturing cost. It is an object to realize a circuit board in which reflected noise and unnecessary electromagnetic radiation are reduced. SOLUTION: A component mounting pad portion 10 is connected to a wiring 13.
And a wiring connection portion 12 having the same width as the pattern and extending the wiring, and a wiring connection portion 12 formed around the wiring connection portion 12 and electrically insulated from the wiring connection portion 12 and necessary for connection with circuit components. Circuit component connection strength assurance unit 11 having area
And

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board and a method of manufacturing the same, and more particularly, to a circuit board having a chip component mounting pad structure in which reflected noise and unnecessary electromagnetic wave radiation are suppressed, and a method of manufacturing the same.

[0002]

2. Description of the Related Art FIG. 5 is a plan view schematically showing an example of the shape of a chip component mounting pad on a conventional circuit board. In FIG. 5, reference numeral 21 denotes a component mounting pad, and reference numeral 22 denotes a pad.
Denotes a component to be mounted, and reference numeral 23 denotes a wiring. The shape of the conventional chip component mounting pad 21 is generally formed to be wider than the width of the general wiring 23.

Here, the characteristic impedance of the wiring 23 is, as shown in FIG.
, The relative permittivity εr of the insulator 24 between the wiring 23 and the GND 25, and the width W of the wiring 23. In a normal circuit board, the characteristic impedance of the wiring on the same layer is almost determined by W, and the larger the W, the smaller the characteristic impedance of the wiring tends to be.

On a certain line, the characteristic impedance Z
Reflectance when from ₀ signal flows to the characteristic impedance Z ₁ has the formula (1) below, whether the value of ρ is calculated by the equation (1) is, how much the reflection occurs for input Is shown. For example, when Z ₁ = Z ₀ , ρ =
0, meaning that all signals input from Z ₀ are transmitted to Z ₁ , meaning that no reflected wave is generated.

Ρ = (Z ₁ −Z ₀ ) / (Z ₁ + Z ₀ ) (1)

Further, radiation noise is classified into common mode noise and normal mode noise, and it is generally said that the influence of common mode noise is large. The main causes of common mode noise are reflected noise due to impedance mismatch between the component 22 and the wiring 23, and
The magnetic field in a certain space cannot be canceled out due to the difference between the current on the transmission side due to the path of the return current being composed of multiple conductors (multiple paths) and the current (return current) returning through the GND 25. It is.

[0007]

However, in the conventional pad shape for mounting components on a circuit board, the pad width is considerably larger than the width of the wiring, and the impedance of the pad portion is larger than the impedance of the wiring. Often very low. For example, as shown in FIG.
The characteristic impedance is about 15Ω in a pad shape having a width. On the other hand, considering that the impedance of a general wiring is about 50Ω, from the reflection equation (1), ρ = 0.
54, 54% of the input is generated as reflection noise at the connection between the wiring and the pad. Due to this reflection noise, the waveform is distorted and the reflected wave becomes a common mode current, which causes a problem that unnecessary electromagnetic radiation is generated.

Further, when the frequency increases, the parameters of the chip component to be used may be far from the original values due to the influence of the parasitic electric parameters of the component mounting pads and the solder connection parts. Reflection is also a problem. Even at high frequencies, it is necessary to reduce parasitic electric parameters as much as possible in order not to generate reflection.

The present invention has been made in view of the above-mentioned circumstances, and secures connection reliability such as peel strength without changing the conventional manufacturing process and without increasing the manufacturing cost. It is another object of the present invention to realize a circuit board and a method of manufacturing the same that reduce reflected noise and unnecessary electromagnetic radiation generated at a component mounting pad portion of the circuit board.

[0010]

In order to achieve the above object, the present invention provides a circuit pattern comprising a wiring portion and a circuit component connection portion connected to the wiring portion, wherein a plurality of circuit component connection portions are provided. In the circuit board on which the circuit component is mounted, the circuit component connection portion is formed around the wiring connection portion and the wiring connection portion having the same pattern width as the wiring portion and forming an extension of the wiring portion. A circuit component connection strength assurance unit having an area required for connection with the circuit component, which is electrically insulated from the wiring connection unit, is provided.

In a method of manufacturing a circuit board having a circuit pattern for mounting circuit components on a surface thereof, a multi-layer board forming step of forming a multi-layer board; and forming a through via hole at a predetermined position of the multi-layer board. Via hole making process
A copper plating step of copper-plating both surfaces of the multilayer substrate and inner surfaces of the through via holes, and a wiring connection at a predetermined position on the both surfaces, the wiring portion and the wiring portion being connected to the wiring portion and having the same width as the wiring portion. And a circuit component connection portion including a circuit component connection strength assurance portion configured around the wire connection portion and electrically insulated from the wire connection portion and having an area necessary for connection with the circuit component. A resist pattern forming step of forming a resist pattern for forming a predetermined circuit pattern to be formed; a circuit pattern forming step of forming the circuit pattern by etching the copper plating using the resist pattern; and Forming a solder resist on the circuit pattern to prevent solder wetting of the copper plating And having a Ruda resist process.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a circuit board according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a plan view schematically showing a component mounting pad portion of a circuit board according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing a manufacturing flow of component mounting pads on the four-layer circuit board according to the embodiment of the present invention. FIG. 3 is a plan view showing a form of forming a resist for component mounting pads according to the embodiment of the present invention. FIG. 4 is a plan view showing an opening form of the solder resist for pad for component mounting according to the embodiment of the present invention. In FIG. 1 to FIG.
Is an insulator, 2 is a copper foil, 3 is a through via hole, 4 is
Is copper plating, reference numeral 5 is a resist, reference numeral 6 is a wiring and pad, reference numeral 7 is a via, reference numeral 8 is a solder resist, reference numeral 9 is a solder resist opening, reference numeral 11 is a connection strength assurance unit, reference numeral 12 is a wiring connection unit, Reference numeral 13 denotes a wiring.

As shown in FIG. 1, in the circuit board according to the present embodiment, the component mounting pad portion 10 surrounds a wiring connection portion 12 which is an extended portion of the wiring, and a periphery of the wiring connection portion 12. The connection part 12 is composed of a connection strength assurance part 11 for soldering parts which are not electrically connected to each other.

With this configuration, when no component is mounted on the component mounting pad portion 10, there is no impedance mismatch from the wiring 13 to the wiring connection portion 12. In addition, even when the components are mounted, the wiring connection unit 12 and the connection strength assurance unit 11 where the components are mounted are not electrically connected to the component connection part.
No impedance mismatch during wiring, 3G
No reflection noise is generated even in a signal containing a high frequency of not less than Hz. Further, unnecessary electromagnetic wave radiation is not generated. In addition, the mounting strength of the components can be maintained such that the area of the connection strength assurance section 11 is the same as that of a conventional pad.

Next, a method of manufacturing a circuit board according to the present invention will be described. As shown in FIG. 2A, a four-layer substrate in which two normally-used two-layer core substrates are laminated, or a prepreg is vertically adhered to the two-layer core substrate, and a copper foil is further adhered thereto is used. prepare. Next, as shown in FIG. 2B, a through-pier hole 3 is formed at a desired position by a drill. Furthermore,
As shown in FIG. 2C, copper plating 4 is performed on the entire surface of the four-layer substrate including the inner surface of the through-pier hole 3. Next, in order to perform an etching process, as shown in FIG. 2D, a resist 5 is formed at a predetermined position. At this time, in the circuit board according to the present invention, since the connection strength assurance portion 11 and the wiring connection portion 12 are formed on the component mounting pad portion 10, a resist having the same dimensions as the component mounting pad portion 10 as shown in FIG. 5 is formed. Next, as shown in FIG. 2E, desired wirings, pads 6 and through piers 7 are formed by etching, and then the resist 5 is removed. Finally, FIG. 2 (f)
A solder resist 8 is formed as shown in FIG. The solder resist opening 9 of the component mounting pad in the present invention is as shown in FIG.

[0016]

As described above, the first aspect of the present invention is provided with a circuit pattern including a wiring portion and a circuit component connection portion connected to the wiring portion, wherein a plurality of circuit component connection portions are provided. In the circuit board on which the circuit component is mounted, the circuit component connection portion includes a wiring connection portion having the same width as the wiring portion and a pattern and forming an extension of the wiring portion, and a wiring connection portion formed around the wiring connection portion and the wiring connection portion. A circuit component connection strength assurance unit having an area that is electrically insulated and has a necessary area for connection with the circuit component. As a result, it is possible to eliminate the impedance mismatch from the wiring to the component connection part. Therefore, even when a signal including a high frequency of 3 GHz or more is propagated, reflected noise is not generated, and waveform distortion and unnecessary electromagnetic wave radiation are generated. Can be eliminated. On the other hand, the mounting strength of parts
The area of the circuit component connection strength assurance portion can sufficiently guarantee the area.

According to a second aspect of the present invention, there is provided a method of manufacturing a circuit board having a circuit pattern on which a circuit component is to be mounted, wherein the step of forming a multilayer board includes the steps of: A via hole forming step of forming a via hole, a copper plating step of copper plating both surfaces of the multilayer substrate and the inner surface of the through via hole, and a wiring portion, and a wiring portion connected to the wiring portion at predetermined positions on both surfaces. A circuit component comprising: a wiring connection portion having an equal width; and a circuit component connection strength assurance portion formed around the wiring connection portion and electrically insulated from the wiring connection portion and having an area required for connection with the circuit component. A resist pattern forming step of forming a resist pattern for forming a predetermined circuit pattern having a connection portion, and a circuit pattern by etching copper plating using the resist pattern; A circuit pattern forming step to create, to the resist pattern peeling step of peeling off the resist pattern, characterized by having a solder resist forming a solder resist for preventing solder wetting of the copper plating on the circuit pattern. As a result, a circuit board free of reflected noise and waveform distortion due to reflection and unnecessary electromagnetic wave radiation can be manufactured by using the conventional manufacturing process as it is, and an increase in manufacturing costs can be suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic plan view of a component mounting pad portion of a circuit board according to the present invention.

FIG. 2 is a diagram showing a manufacturing flow of a four-layer circuit board according to the circuit board manufacturing method of the present invention.

FIG. 3 is a view showing a resist form of a component mounting pad portion used in the present invention.

FIG. 4 is a view showing an opening form of a solder resist in a component mounting pad portion used in the present invention.

FIG. 5 is a plan view schematically showing the shape of a component mounting pad on a conventional circuit board.

FIG. 6 is a schematic cross-sectional view of a circuit board showing parameters for determining a characteristic impedance of a conventional wiring unit.

FIG. 7 is a schematic cross-sectional view of a circuit board showing parameters for determining a characteristic impedance of a conventional component mounting pad.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulator, 2 ... Copper foil, 3 ... Through-hole, 4 ... Copper plating, 5 ... Resist, 6 ... Wiring and pad, 7 ... Via,
8 solder resist, 9 solder resist opening,
10: pad part for component mounting, 11: connection strength assurance unit,
12: wiring connection part, 13: wiring, 21: component mounting pad, 22: mounted component, 23: wiring

Claims (2)

[Claims] 1. A circuit board having a circuit pattern including a wiring portion and a circuit component connection portion connected to the wiring portion, wherein a circuit component is mounted between the plurality of circuit component connection portions. A wiring connection portion having the same width as the wiring portion and the pattern and forming an extension of the wiring portion; and the circuit component formed around the wiring connection portion and electrically insulated from the wiring connection portion. A circuit component connection strength assurance unit having an area required for connection of the circuit board. 2. A method of manufacturing a circuit board having a circuit pattern for mounting a circuit component on a surface thereof, comprising: a step of forming a multilayer board; and forming a through via hole at a predetermined position on the multilayer board. A via hole forming step, a copper plating step of copper plating both surfaces of the multilayer substrate and an inner surface of the through via hole, a wiring portion at a predetermined position on the both surfaces, and the wiring portion connected to the wiring portion. And a circuit component connection strength assurance portion configured around the wire connection portion and electrically insulated from the wire connection portion and having an area required for connection with a circuit component. A resist pattern forming step of forming a resist pattern for forming a predetermined circuit pattern including a component connecting portion; and etching the copper plating using the resist pattern. Pattern forming step of forming the circuit pattern by performing a soldering process; a resist pattern stripping step of stripping the resist pattern; and a solder resist step of forming a solder resist for preventing solder wetting of the copper plating on the circuit pattern. And a method for manufacturing a circuit board.