JP4649378B2 - Circuit board manufacturing method and electronic circuit unit using the circuit board - Google Patents

Description

  The present invention relates to a method for manufacturing a circuit board suitable for use in a mobile phone, various electric devices, and the like, and an electronic circuit unit using the circuit board.

  FIG. 12 is an exploded perspective view of a conventional electronic circuit unit, and FIG. 13 is a schematic diagram of a conventional electronic circuit unit. FIG. 14 relates to a conventional electronic circuit unit, and is an enlarged cross-sectional view of the main part of the circuit board. FIG. 15 relates to a conventional electronic circuit unit, and is an enlarged plan view of the main part of the circuit board. FIG. 20 is an explanatory view showing a manufacturing process according to a conventional circuit board manufacturing method.

  Next, the configuration of the conventional electronic circuit unit will be described with reference to FIGS. 12 and 13. The circuit board 51 has a rectangular shape and has mounting holes 52 in the vicinity of the corners. Although not shown here, a wiring pattern including a signal pattern and a grounding pattern is provided, and various electronic components are mounted.

  The box-shaped metal cover 53 has a plurality of attachment legs 54 having protrusions 54 a in a state of being located in the metal cover 53, and the protrusions 54 a are inserted into the attachment holes 52 in the attachment legs 54. In the state, the circuit board 51 is placed.

  Further, a lid 55 is attached to the metal cover 53 so as to cover the open portion of the metal cover 53, and when the lid 55 is attached, it protrudes into a hole 56 a of a pressing portion 56 provided in the lid 55. The part 54a is inserted, and the circuit board 51 is sandwiched between the mounting leg 54 and the pressing part 56 to form a conventional electronic circuit unit (see, for example, Patent Document 1).

  Further, in the circuit board 51 made of a ceramic material used in such a conventional electronic circuit unit, in order to ground the metal cover 53 to the grounding pattern provided on the circuit board 51, FIG. 15, through holes 51a provided in the vicinity of the corners of the circuit board 51, land portions 57 as a part of the wiring pattern provided on the outer peripheral surface of the through holes 51a, and mounting holes 52 Are formed on the inner wall of the through hole 51a with a uniform thickness, and the exposed surface of the conductor 58 and the solderable metal film 59 provided on the land portion 57 are provided. Yes.

  The projection 54 a is inserted into the mounting hole 52 of the circuit board 51 having such a configuration, and the tip (shoulder) of the mounting leg 54 comes into contact with the metal film 59 on the land portion 57. The metal cover 53 is grounded by soldering 60 between the mounting leg 54 and the metal film 59 on the land portion 57.

  However, when the solder 60 is attached to the metal film 59 on the land portion 57, as shown in FIG. 14, the outer end portion of the land portion 57 located on the one surface side is located away from the through hole 51a, and the land portion Between the outer end portion 57 and the through hole 51a on the other surface side without the land portion 57, there is a flesh portion 51b of the circuit board 51 as shown by a dotted line. Due to the stress of the solder 60 due to hardening or the like, cracks and chips occur at the position of the meat portion 51b.

  Next, a conventional circuit board manufacturing method used in such an electronic circuit unit will be described with reference to FIGS. 16 to 20. First, as shown in FIG. After performing the land portion forming step of providing the land portion 57 simultaneously with the formation of the wiring pattern, the through hole forming step of providing the through hole 51a in the center portion of the land portion 57 in the circuit board 51 as shown in FIG. I do.

Next, as shown in FIG. 18, after performing a filling step of filling the paste-like conductor 58 into the through-hole 51a, an attachment hole 52 is provided at the center of the conductor 58 as shown in FIG. The mounting hole forming step is performed to form the conductor 58 having a uniform thickness, and then the circuit board 51, the wiring pattern including the land portion 57, and the firing step of firing the conductor 58 are performed, and then FIG. As shown in FIG. 5, when the metal film forming step for forming the metal film 59 on the exposed surfaces of the land portion 57 and the conductor 58 is performed by plating, the manufacture of the conventional circuit board is completed.
Japanese Patent Laid-Open No. 10-303590

  However, in the conventional circuit board manufacturing method, since the land portion 57 is provided on the outer periphery of the through hole 51a of the circuit board 51, the circuit board 51 becomes large in size and the material cost is increased, and the mounting is performed. Since the hole 52 is provided in the central portion of the conductor 58, the mounting hole 52 is close to the outer peripheral portion of the circuit board 51, the circuit board 51 becomes larger, and the solder 60 is attached to the metal film 59 on the land portion 57. In such a case, the stress of the solder 60 causes a problem that the flesh 51b near the through hole 51a of the circuit board 51 is cracked or chipped.

  Further, in the conventional electronic circuit unit, since the land portion 57 is provided on the outer periphery of the through hole 51a of the circuit board 51, the circuit board 51 becomes large and the material cost becomes high, and the mounting hole 52 is increased. Is provided at the center of the conductor 58, the mounting hole 52 is close to the outer periphery of the circuit board 51, the circuit board 51 is enlarged, and the leg part 54 of the metal cover 53 is the metal on the land part 57. Since the solder 60 is attached to the film 59, there is a problem that the stress of the solder 60 causes a crack or a chip in the meat portion 51 b near the through hole 51 a of the circuit board 51.

  The present invention has been made in view of the actual situation of the prior art, and the object thereof is a method for manufacturing a circuit board that is small in size, low in material cost, and free from cracks and chips due to the stress of solder, and the circuit board. It is to provide an electronic circuit unit using the.

  In order to achieve the above object, the present invention includes a step of forming a through hole in a circuit board made of a ceramic material, a step of filling a paste-like conductor in the through hole, and a deviation from the center of the through hole. Position, the step of forming a part mounting hole smaller than the diameter of the through hole at the position of the conductor, the step of firing the circuit board and the conductor, and soldering to the exposed surface of the conductor by plating It is characterized by comprising a step of forming a metal film.

  In the present invention configured as described above, since the land portion does not exist in the outer peripheral portion of the through hole of the circuit board, the circuit board can be reduced in size, the material cost is reduced, and the hole for attaching the component is penetrated. Since the hole is formed at a position deviated from the center of the hole, the hole can be arranged on the inner side of the circuit board, and the circuit board can be reduced in size. Since the metal film provided at the position of the thick portion enables soldering of the component, it is possible to obtain a component that is free from cracks and chips near the through hole of the circuit board.

  In addition, the present invention is characterized in that, in the above invention, the through hole is formed in the vicinity of the corner of the rectangular circuit board, and the hole is formed to be shifted toward the center of the circuit board. .

  In the present invention configured as described above, since the hole portion is formed so as to be shifted to the center portion side of the circuit board, the position of the hole portion is closer to the center portion side and the outer shape of the circuit board can be reduced. The size can be reduced.

  The present invention is characterized in that, in the above-described invention, the metal film is connected to a grounding pattern provided on the circuit board in the step of forming the metal film.

  In the present invention configured as described above, a simple connection between a metal film to which a component is attached and a grounding pattern can be obtained.

  In order to achieve the above object, the present invention comprises a circuit board made of a ceramic material provided with a wiring pattern, the circuit board comprising a through hole and a conductor provided on the inner wall surface of the through hole, A hole for mounting a component smaller than the diameter of the through hole provided at the position of the conductor at a position shifted from the center of the through hole, and a solderable metal film provided on the exposed surface of the conductor The conductor is characterized in that it has a circuit board provided with a thick portion by varying the thickness in the radial direction of the through hole depending on the hole portion.

  In the present invention configured as described above, since the land portion does not exist in the outer peripheral portion of the through hole of the circuit board, the circuit board can be reduced in size, the material cost is reduced, and the hole for attaching the component is penetrated. Since the hole is formed at a position deviated from the center of the hole, the hole can be arranged on the inner side of the circuit board, and the circuit board can be reduced in size. Since the metal film provided at the position of the thick portion enables soldering of the component, it is possible to obtain a component that is free from cracks and chips near the through hole of the circuit board.

  Further, in the present invention, in the above invention, the through hole is formed in the vicinity of the corner of the rectangular circuit board, and the hole is formed to be shifted toward the center of the circuit board. A mounting leg of a metal cover forming a part is inserted, and the mounting leg is soldered to a metal film.

  In the present invention configured as described above, since the hole portion is formed so as to be shifted to the center portion side of the circuit board, the position of the hole portion is closer to the center portion side and the outer shape of the circuit board can be reduced. In addition to miniaturization, the mounting legs are soldered at the position of the metal film provided at the position of the thick part of the conductor, so that there is no crack or chipping in the vicinity of the through hole of the circuit board. It is done.

Further, in the above invention, the circuit board is provided with grounding patterns, and characterized in that the ground pattern is connected to the metal film.

  According to the present invention configured as described above, a simple connection between the metal film to which the metal cover is attached and the grounding pattern can be obtained, and a reliable grounding of the metal cover can be obtained.

  Further, the present invention is characterized in that, in the above invention, the metal film is formed of a gold material.

  In the present invention configured as described above, since a gold material having good solderability is used, a reliable solder can be obtained even in a small area.

  In the present invention, since the land portion does not exist on the outer peripheral portion of the through hole of the circuit board, the circuit board can be reduced in size, the material cost is reduced, and the hole for mounting the component is shifted from the center of the through hole. Since the hole portion can be arranged on the inner side of the circuit board, the circuit board can be reduced in size, and the conductor can be provided with a thick portion with different thicknesses. Since the metal film provided at the position of the thick portion enables the component to be soldered, a product having no cracks or chips near the through hole of the circuit board can be obtained.

  FIG. 1 is a plan view of an electronic circuit unit according to the present invention, FIG. 2 is a front view of a part of the electronic circuit unit according to the present invention, and a partial cross-sectional view thereof. FIG. 3 relates to the electronic circuit unit of the present invention, and is an enlarged plan view of the main part of the circuit board. FIG. 4 relates to the electronic circuit unit of the present invention and is an enlarged cross-sectional view of the main part of the circuit board.

  5 is a plan view showing a process of forming a through hole according to the method for manufacturing a circuit board of the present invention, and FIG. 6 is a cross-sectional view showing a process of forming the through hole according to the method of manufacturing a circuit board of the present invention. FIG. 7 is a plan view showing a step of filling a conductor according to the circuit board manufacturing method of the present invention, and FIG. 8 is a cross-sectional view showing a step of filling the conductor according to the circuit board manufacturing method of the present invention. 9 is a plan view showing a process of forming a hole for mounting a component according to the circuit board manufacturing method of the present invention. FIG. 10 is a hole for mounting the component according to the circuit board manufacturing method of the present invention. FIG. 11 is a cross-sectional view showing a step of forming a metal film according to the circuit board manufacturing method of the present invention.

  Next, the configuration according to the electronic circuit unit of the present invention will be described with reference to FIGS. 1 to 4. The circuit board 1 made of a ceramic material has a quadrangular shape, and a through hole 2 provided in the vicinity of a corner portion, Provided on the inner wall surface of the through-hole 2, the conductor 3 made of silver, silver palladium or the like, and at a position shifted from the center of the through-hole 2, the diameter of the through-hole 2 provided at the position of the conductor 3 It has a hole 4 for mounting a component (for example, a metal cover) and a metal film 5 that can be soldered with gold or copper provided on the exposed surface of the conductor 3 by plating.

  As shown in FIG. 3, the conductor 3 is formed by shifting the hole 4 in the central portion C direction of the circuit board 1, thereby varying the thickness of the through hole 2 in the radial direction. It has the thick part 3a located in the corner | angular part side, By this structure, the hole 4 becomes far from the outer peripheral part of the circuit board 1, and the external shape of the circuit board 1 can be shrunk | reduced.

  Further, the circuit board 1 is provided with a wiring pattern 6 having a signal pattern 6a and, for example, a grounding pattern 6b located on the lower surface, and the grounding pattern 6b is electrically connected to the metal film 5, and Various electronic components 7 are mounted on the circuit board 1 to form a desired electric circuit.

  The box-shaped metal cover 8 has a box-shaped shield part 9 and mounting legs 10 protruding downward from the shield part 9, and the metal cover 8 covers the electronic component 7 with the shield part 9. The mounting leg 10 is inserted into the hole 4, and the mounting leg 10 is attached to the metal film 5 provided on the surface of the conductor 3 by soldering 11 to form the electronic circuit unit of the present invention. .

  Then, the solder 11 can be attached due to the presence of the thick portion 3a of the conductor 3, which eliminates the need for a land portion around the through hole 2, and as shown in FIG. Since it is formed on the metal film 5 on the conductor 3, there is no flesh of the circuit board 1 below the solder 11, and the circuit board 1 is not cracked or chipped due to the stress of the solder 11.

  In the above embodiment, the metal cover 8 is used as the component to be attached by the hole 4, but components other than the metal cover may be used.

  Next, the manufacturing method of the circuit board of the present invention used in such an electronic circuit unit will be described with reference to FIGS. 5 to 11. First, as shown in FIGS. After the step of forming the through hole 2 in the substrate 1, as shown in FIGS. 7 and 8, the step of filling the paste-like conductor 3 into the through hole 2 is performed, and then FIG. As shown in FIG. 10, a step of forming a part mounting hole 4 smaller than the diameter of the through hole 2 provided at the position of the conductor 3 at a position shifted from the center of the through hole 2 is performed.

  The step of forming the hole 4 forms the thick portion 3a, and at the time of forming the hole 4, the hole 4 reaches the circuit board 1 over the through hole 2. Also good.

  Next, after performing the process of baking the circuit board 1 and paste-like conductor 3 which consist of a green sheet, as shown in FIG. 11, the process of forming the metal film 5 on the exposed surface of the conductor 3 by plating, as shown in FIG. When this metal film 5 is connected to the grounding pattern 6b, the manufacture of the circuit board of the present invention is completed.

It is a top view which concerns on the electronic circuit unit of this invention. FIG. 4 is a front view of a part of the electronic circuit unit according to the present invention, the sectional view of which is shown. It is an enlarged plan view of the principal part of a circuit board concerning the electronic circuit unit of this invention. It is an expanded sectional view of the principal part of a circuit board concerning the electronic circuit unit of this invention. It is a top view which shows the process of forming the through-hole in the manufacturing method of the circuit board of this invention. It is sectional drawing which shows the process of forming the through-hole in the manufacturing method of the circuit board of this invention. It is a top view which shows the process of filling with a conductor in the manufacturing method of the circuit board of this invention. It is sectional drawing which shows the process of filling with a conductor concerning the manufacturing method of the circuit board of this invention. It is a top view which shows the process of forming the hole for component attachment in the manufacturing method of the circuit board of this invention. It is sectional drawing which shows the process of forming the hole for component attachment in the manufacturing method of the circuit board of this invention. It is sectional drawing which shows the process of forming the metal film in the manufacturing method of the circuit board of this invention. It is a disassembled perspective view which concerns on the conventional electronic circuit unit. It is an expanded sectional view of the principal part concerning the conventional electronic circuit unit. It is an expanded sectional view of the principal part of a circuit board concerning a conventional electronic circuit unit. It is an enlarged plan view of the principal part of a circuit board concerning a conventional electronic circuit unit. It is explanatory drawing which shows the land part formation process in connection with the manufacturing method of the conventional circuit board. It is explanatory drawing which shows the through-hole formation process in connection with the manufacturing method of the conventional circuit board. It is explanatory drawing which shows the filling process of a conductor in connection with the manufacturing method of the conventional circuit board. It is explanatory drawing which shows the attachment hole formation process in connection with the manufacturing method of the conventional circuit board. It is explanatory drawing which shows the metal film formation process in connection with the manufacturing method of the conventional circuit board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 2 Through-hole 3 Conductor 3a Thick part 4 Hole part 5 Metal film 6 Wiring pattern 6a Signal pattern 6b Grounding pattern 7 Electronic component 8 Metal cover 9 Shield part 10 Mounting leg 11 Solder C Center part

Claims (7)

  A step of forming a through hole in a circuit board made of a ceramic material, a step of filling the through hole with a paste-like conductor, and a position shifted from the center of the through hole at the position of the conductor. Forming a part mounting hole smaller than the diameter of the hole, firing the circuit board and the conductor, and forming a solderable metal film on the exposed surface of the conductor by plating. A method for manufacturing a circuit board, comprising:   2. The circuit according to claim 1, wherein the through hole is formed in the vicinity of a corner portion of the circuit board having a quadrangular shape, and the hole section is formed so as to be shifted toward a center portion side of the circuit board. A method for manufacturing a substrate.   3. The method of manufacturing a circuit board according to claim 1, wherein the metal film is connected to a grounding pattern provided on the circuit board in the step of forming the metal film.   A circuit board made of a ceramic material provided with a wiring pattern is provided. The circuit board includes a through hole, a conductor provided on an inner wall surface of the through hole, and the conductive material at a position shifted from the center of the through hole. A hole for mounting a component smaller than the diameter of the through hole provided at the position of the body, and a solderable metal film provided on the exposed surface of the conductor, An electronic circuit unit comprising the circuit board provided with a thick portion by varying a thickness in a radial direction of the through hole depending on a hole.   The through-hole is formed in the vicinity of a corner of the quadrangular circuit board, and the hole is formed to be shifted toward the center of the circuit board, and the component is formed in the hole. 5. The electronic circuit unit according to claim 4, wherein a mounting leg of a metal cover is inserted and the mounting leg is soldered to the metal film. Wherein the circuit board, a ground pattern is provided, the electronic circuit unit according to claim 4 or 5, wherein said ground pattern is connected to the metal film.   The electronic circuit unit according to claim 4, wherein the metal film is made of a gold material.

Images