Abstract: The present invention provides a production method of a printed circuit board having a circuit pattern with a little variation in the thickness at a low cost without a special step for removal of a dummy pattern. The present invention is characterized in that an insulating layer 2 is formed in a given pattern on one surface of a supporting substrate 1, a circuit pattern 6 is formed on the insulating layer 2 while forming a dummy pattern 7 in an area free of the insulating layer 2 on the one surface of the supporting substrate 1, and an unnecessary part of the supporting substrate 1, which is free of the insulating layer 2 and the circuit pattern 6, is removed by dissolution together with the dummy pattern 7.

Abstract: The present invention provides a partially completed wiring circuit board assembly sheet capable of preventing deposition of a plating metal on the surface of a metal sheet, even when pinholes are produced in an insulating layer for insulating a lead wire for electroplating from a metal sheet. The assembly sheet 100 of the present invention has a metal sheet 1, multiple wiring circuit board forming area 1A in compartments on the metal sheet and area 1B for forming a lead wire for electroplating, which is in compartment on the metal sheet 1. Each area 1A has a partially completed wiring circuit board 10. The partially completed wiring circuit board 10 is equipped with a base insulating layer 2, a wiring pattern 3 and a cover insulating layer 4. In the area 1B, a first insulating layer 12, a lead wire 13 for electroplating and a second insulating layer 14 are laminated in this order. Of the metal sheet 1, an opening 16 is formed in the part under the lead wire 13.

Abstract: A production method of a suspension board with circuit that can provide reduced number of man-hour and complicated processes for forming the ground terminal, to provide production cost reduction. An insulating base layer 4 having a base opening portion 3 is formed on a metal board 2 at a ground terminal 13 forming position, and a thin metal film 5 is formed on the metal board 2 exposed in the base opening portion 3 and on the insulating base layer 4. Then, a conductive pattern 7 is formed on the thin metal film 5. Then, an insulating cover layer 9 covering the conductive pattern 7 and having a cover opening portion 8 which correspond in position to the base opening portion 3 is formed on the insulating base layer 4. Then, a metal board opening portion 11 from which the base opening portion 3 and the insulating base layer 4 around it are exposed is formed in the metal board 2.

Abstract: A production method of a suspension board with circuit that can reduce variations in diameter of the location holes or like holes formed in the suspension board and can produce a trim contour of the suspension board. In the process of forming a seed film 12, zirconium is previously deposited on a surface of the suspension board 2 by sputtering a conductive material forming the seed film 12 using an electrode formed of zirconium. Or, in the process of forming a metal coating 14, palladium is previously deposited on the surface of the suspension board 2 by electroless-plating the thin metal film forming the metal coating 14 using a catalyst including palladium. Thereafter, the suspension board 2 formed of stainless is trimmed by the chemical etching. This can allow an end face 17 of the suspension board 2 to be chemically etched evenly.

Abstract: In the vicinity of the exposed part 1A of the multiply formed plural wiring conductors 1, of the thicknesses of the insulating cover layer 2 made of a polyimide layer, the thickness (T1) of a part located at about the middle point between the adjacent wiring conductors 1 is made smaller than the thickness (T2) of a part located on wiring conductor 1. Preferably, the difference in the thicknesses of a part located at about the middle point between the adjacent wiring conductors of the insulating cover layer 2 and that of a part located on wiring conductor is made to fall within the range of 1-5 ?m. As a result, the insulating cover layer does not peel off easily.

Abstract: A producing method of a suspension board with circuit that can permit a terminal portion to be formed by electrolysis plating without exposing a conductor layer to outside and also can reduce the number of processes, and the suspension board with circuit produced by the same producing method. After an insulating base layer 3 is formed on a suspension board 2 in a specific pattern in which a second opening 12 is formed, a thin metal film 13 is formed on an entire surface of the insulating base layer 3 and on a surface of the suspension board 2 including the second opening 12 exposed from the insulating base layer 3.Then, a conductor layer 4 is formed in the form of a wired circuit pattern on the thin metal film 13. Thereafter, the insulating cover layer 10 is formed in such a manner that a pad opening 11 is formed in the insulating cover layer 10 and then a pad portion 16 is formed in the pad opening 11 using the suspension board 2 as a lead portion of the electrolysis plating.

Abstract: A wired circuit board that can control characteristic impedance at connection points between wires of a suspension board with circuit and terminal portions of the wired circuit board connected thereto with a simple structure, to improve signal transmission efficiency even for fine pitch wiring or for high frequency signal. To provide this wired circuit board, a relay flexible wiring circuit board 1 is formed by a first wired circuit board 14 comprising a first metal substrate 16, a first insulating base layer 17, a first conductor layer 18 and a first insulating cover layer 19 which is substantially identical in layer structure with the suspension board with circuit 3 and a second wired circuit board 15 connected with the first wired circuit board 14 for connecting with a control circuit board 4.

Abstract: A wired circuit board that can control characteristic impedance at connection points between the read wire and write wire of a suspension board with circuit and terminal portions of the wired circuit board connected thereto with a simple structure, to improve signal transmission efficiency for fine pitch wiring or for high frequency signal. A conductive board 25 is adhesively bonded to an insulating base layer 18 of the wired circuit board 1 at one side thereof opposite to the other side on which a suspension-board-side connection terminal portion 11 having a first terminal portion 13 to connect with a read wire 6R of a suspension board with circuit 3 and a second terminal portion 14 to connect with a write wire 6W of the suspension board with circuit 3 is formed, in such a relation that an opening 27 can correspond in position to either of the first terminal portion 13 and the second terminal portion 14, and a stiffener board 24 is adhesively bonded to the conductive board 25 via an adhesive layer 28.

Abstract: In a junction flexible wiring circuit board used for performing junction between a suspension board for mounting a magnetic head of a hard disk drive thereon and a control circuit board for operating the magnetic head, a metal layer is formed on at least one of a surface of an electrically insulating base layer and a surface of an electrically insulating cover layer.

Abstract: A flexible wired circuit board for temperature measurement that can provide an accurate temperature measurement even when placed in a high-temperature atmosphere and can also be provided at a reduced cost. In the flexible wired circuit board for temperature measurement, a conductor layer formed from a metal foil, such as a stainless foil, having a proportional relation between temperature and specific electric resistance is formed on a base insulating layer. Also, a single thin sensor wiring in a sensor portion exposed from a cover insulating layer is formed into a certain pattern by folding back the sensor wiring in a continuous S-shaped form, such that adjacent parts of the wiring extending in parallel are spaced apart from each other at a predetermined interval in a widthwise direction of the conductor layer.

Abstract: A nickel plating layer having a thickness within a range of 1.0 to 4.0 &mgr;m is formed in a terminal portion of a circuit board as an underlying plating layer. After a soldering bump is formed on the underlying plating layer, the soldering bump is connected to an external terminal formed in an external circuit.

Abstract: The present invention provides a production method of a printed circuit board having a circuit pattern with a little variation in the thickness at a low cost without a special step for removal of a dummy pattern. The present invention is characterized in that an insulating layer 2 is formed in a given pattern on one surface of a supporting substrate 1, a circuit pattern 6 is formed on the insulating layer 2 while forming a dummy pattern 7 in an area free of the insulating layer 2 on the one surface of the supporting substrate 1, and an unnecessary part of the supporting substrate 1, which is free of the insulating layer 2 and the circuit pattern 6, is removed by dissolution together with the dummy pattern 7.

Abstract: In a junction flexible wiring circuit board used for performing junction between a suspension board for mounting a magnetic head of a hard disk drive thereon and a control circuit board for operating the magnetic head, a metal layer is formed on at least one of a surface of an electrically insulating base layer and a surface of an electrically insulating cover layer.

Abstract: A nickel plating layer having a thickness within a range of 1.0 to 4.0 &mgr;m is formed in a terminal portion of a circuit board as an underlying plating layer. After a soldering bump is formed on the underlying plating layer, the soldering bump is connected to an external terminal formed in an external circuit.

Abstract: To provide a suspension board with circuit that enables its terminals to be bonded to the other terminals with sufficient strength with simple structure, to ensure sufficient bonding reliability, the suspension board with circuit 11 includes a suspension board 12, a base layer 13 formed on the suspension board 12, and a conductive layer 14 formed on the base layer 13 and a cover layer 18 with which the conductive layer 14 is covered, wherein external connection terminals 17 to be bonded to terminals 28 of a read/write board 29 are formed without the suspension board 12 and/or the base layer 13 being formed.

Abstract: To provide a circuit board, having a circuit pattern of adequate high-frequency characteristics, for transmitting high-frequency electric signals at high speed, a circuit board, including a base layer formed of insulating material and a conductive layer formed on the base layer in the form of a specified circuit pattern, is so constructed that an air layer is made to lie between lines of wire of the circuit pattern or is so constructed that the lines of wire are covered with the cover layer but land portions of the base layer extending between the lines of wire are not covered with the cover layer. This construction of the invention enables dielectric constant between the lines of wire to be reduced and, as a result of this, the capacitance between the lines of wire can be reduced to provide improved high-frequency characteristics of the circuit pattern.

Abstract: In a circuit board with a conductor circuit formed on an insulating layer, a covering is formed on the conductor circuit and a terminal is connected to the conductor circuit penetrating through the covering to obtain high reliability for the connection between the terminal of the electronic component mounted on the circuit board and that of the circuit board. There is provided a level difference of 3 &mgr;m or less between the surface of the covering and that of the terminal.