JP2006344686A - Manufacturing method of microwave transmission circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the manufacturing method of a microwave transmission circuit substrate capable of obtaining sufficient adhesiveness by a method having no problem with respect to environment. <P>SOLUTION: The manufacturing method of the microwave transmission circuit substrate comprises a process for forming the titanium film 2 on the surface of a form 1 having a three-dimensional configuration, and further forming a copper film 3 on the titanium film 2; a process for removing the copper film 3 and the titanium film 2 on a boundary line by irradiating electromagnetic wave against the copper film 3, along the boundary line between a circuit region for constituting the circuit and a non-circuit region for constituting no circuit; and a forming process of a copper plating layer 4 by applying copper plating on the copper film 3a in the circuit region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a three-dimensional circuit board.

Conventionally, as a method for manufacturing a three-dimensional circuit board (MID: Molded Interconnect Device) in which a circuit is formed on the surface of a molded body having a three-dimensional shape with unevenness, for example, a manufacturing method described in Patent Document 1 is known. It has been. In this manufacturing method, first, a base film that serves as a base for plating is formed on the surface of the molded body, and then the boundary line between the circuit region that constitutes the circuit and the non-circuit region that does not constitute the circuit with respect to the base film. A base film on the boundary line is removed by irradiating an electromagnetic wave such as a laser along the line, and finally, a copper plating layer is formed by performing copper plating on the base film in the circuit region.
Japanese Patent No. 3153682

  As the base film, it is preferable to use a material having a low resistance such as copper. Therefore, it is conceivable to use chromium as the intermediate film. However, if this is done, there is a problem that hexavalent chromium is discharged in the etching process, which adversely affects the environment.

  In view of such circumstances, an object of the present invention is to provide a method of manufacturing a three-dimensional circuit board capable of obtaining sufficient adhesion by a method that does not adversely affect the environment.

  In order to achieve the above object, according to a first means of the present invention, in the method of manufacturing a three-dimensional circuit board, a titanium film is formed on the surface of a molded body having a three-dimensional shape, and a copper film is further formed thereon. The step of forming and irradiating the copper film with electromagnetic waves along a boundary line between a circuit area constituting a circuit and a non-circuit area not constituting a circuit, and removing the copper film and the titanium film on the boundary line And a step of performing copper plating on the copper film in the circuit region to form a copper plating layer.

  In order to improve the insulation reliability between the circuits, the step of removing the copper film in the non-circuit region to expose the titanium film, and the titanium film in the non-circuit region are subjected to an oxidation treatment to form the titanium film. It is preferable to further include the step of.

  Alternatively, the step of removing the copper film in the non-circuit area to expose the titanium film, and forming the copper plating layer and exposing the titanium film in the non-circuit area, and then exposing the ion beam to the circuit area and the non-circuit area. And a step of removing the titanium film in the non-circuit region by irradiating the film.

  Alternatively, the step of removing the copper film in the non-circuit region and exposing the titanium film, and forming the copper plating layer and exposing the titanium film in the non-circuit region, and then performing a blast process to And a step of removing the titanium film.

  Further, the step of removing the copper film in the non-circuit region to expose the titanium film, nickel plating on the copper plating layer, and gold plating thereon to form a nickel / gold plating layer It is also possible to further include a step and a step of removing the titanium film in the non-circuit region by performing etching after forming the nickel / gold plating layer.

  In the second means of the present invention, in the method of manufacturing a three-dimensional circuit board, sputtering is performed using a target composed of titanium and copper, so that titanium and A step of forming a mixed film of copper, and irradiating the mixed film with electromagnetic waves along a boundary line between a circuit area constituting a circuit and a non-circuit area not constituting a circuit; A step of removing, and a step of performing copper plating on the mixed film in the circuit region to form a copper plating layer.

  In the third means of the present invention, in the method of manufacturing a three-dimensional circuit board, a target having a three-dimensional shape is transported in a direction from the target titanium to the copper using a target configured by arranging titanium and copper side by side. A step of forming a mixed film of titanium and copper on the surface of the formed body by sputtering, and along the boundary line between the circuit region constituting the circuit and the non-circuit region not constituting the circuit with respect to the mixed film. The method includes a step of irradiating electromagnetic waves to remove the mixed film on the boundary line, and a step of performing copper plating on the mixed film in the circuit region to form a copper plating layer.

  According to the first means of the present invention, since the titanium film is formed between the surface of the molded body and the copper film, the copper film and the molded body can be firmly bonded by the titanium film, and sufficient adhesion is achieved. Sex can be obtained. Moreover, titanium does not have an adverse effect on the environment.

  According to the 2nd means of this invention, since the mixed film of titanium and copper was formed in the surface of a molded object, the joint strength of a molded object and a mixed film improves, and sufficient adhesiveness can be obtained. Further, by using a mixed film of titanium and copper, the mixed film in the non-circuit region can be removed by a single etching, and titanium can be easily removed because titanium is mixed in copper.

  According to the third means of the present invention, since a sputtering is carried out using a target composed of titanium and copper while carrying the formed body to form a mixed film of titanium and copper on the surface of the formed body, As for the ratio of titanium and copper in the mixed film, the amount of titanium increases in the vicinity of the surface of the molded body, and the amount of copper increases as the distance from the surface increases. That is, since titanium is increased in the vicinity of the surface of the molded body, the bonding strength between the molded body and the mixed film is further improved, and more sufficient adhesion can be obtained. Moreover, since there is no interface between titanium and copper in the mixed film, the ratio of copper at the boundary with the copper plating layer can be increased while keeping the strength of the mixed film itself high. Bonding strength can also be improved.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  With reference to FIG.1 and FIG.2, the manufacturing method of the three-dimensional circuit board based on 1st Embodiment of this invention is demonstrated. This method of manufacturing a three-dimensional circuit board includes the following six steps.

1) Titanium film and copper film forming step First, as shown in FIGS. 1A to 1C, a titanium film 2 is formed on the surface of a molded body 1 having a three-dimensional shape with irregularities, and further A copper film 3 is formed thereon. The molded body 1 is formed by molding an insulating material into a predetermined shape by injection molding or press molding. As the insulating material, ceramic materials such as alumina, aluminum nitride, and silicon carbide, and resin materials such as PPS (polyphenylene sulfide), PEEK (polyether ether ketone), and polyphthalamide can be used. As the molded body 1, it is also possible to use a metal core substrate or the like in which copper or aluminum is formed in a predetermined shape and is coated with an insulating material.

  Formation of the titanium film 2 and formation of the copper film 3 can be performed by sputtering. The thickness of the titanium film 2 is preferably in the range of 5 to 100 nm and as thin as possible. Moreover, it is preferable that the thickness of the copper film 3 exists in the range of 100-1000 nm, and should just be a grade which can be electroplated later.

2) Laser irradiation step After the titanium film 2 and the copper film 3 are formed, as shown in FIG. 1 (d), the boundary between the circuit area constituting the circuit and the non-circuit area not constituting the circuit with respect to the copper film 3. The copper film 3 and the titanium film 2 on the boundary line are removed by irradiating an electromagnetic wave such as a laser 11 along the line. As a result, the copper film 3a in the circuit region and the copper film 3b in the non-circuit region are separated, and the titanium film 2a in the circuit region and the titanium film 2b in the non-circuit region are separated. As the laser 11, for example, a second harmonic YAG (yttrium aluminum garnet) laser (wavelength 532 nm), a third harmonic YAG laser (wavelength 355 nm), or a KrF excimer laser (wavelength 248 nm) can be used. As the electromagnetic wave, X-rays or ultraviolet rays can be used, but the laser 11 is most preferable.

3) Copper plating step After removing the copper film 3 and the titanium film 2 on the boundary line between the circuit area and the non-circuit area, as shown in FIG. 1 (e), copper plating is performed on the copper film 3a in the circuit area by electroplating. And a copper plating layer 4 having a thickness of about 5 to 50 μm is formed. Since the copper film 3a in the circuit area and the copper film 3b in the non-circuit area are separated, a cathode is connected to the copper film 3a in the circuit area, and the molded body 1 is energized while being immersed in a plating bath. The copper plating layer 4 can be easily formed only on the copper film 3a in the circuit region.

4) Copper film removal step After forming the copper plating layer 4, as shown in FIG. 1 (f), etching is performed using an ammonium persulfate solution, a cupric chloride solution, or the like, thereby forming a copper film in a non-circuit region. 3b is removed to expose the titanium film 2b in the non-circuit region. Etching is performed by immersing the molded body 1 in an ammonium persulfate solution or a cupric chloride solution for a short time. Since the thickness of the copper plating layer 4 is sufficiently larger than the thickness of the copper film 3b, the copper film 3b can be removed while leaving the copper plating layer 4 on the copper film 3a in the circuit region.

5) Titanium film removal process After exposing the titanium film 2b in the non-circuit region, as shown in FIGS. 2A and 2B, the circuit region and the non-circuit region are irradiated with, for example, an ion beam of argon. The titanium film 2b in the region is removed. When the ion beam is irradiated, it is preferable to use a multi-axis table 12 as shown in FIG. For example, as shown in FIG. 3B, the molded body 1 is fixed on the multi-axis table 12, and the ion source 13 is installed obliquely above the multi-axis table 12, and the multi-axis table 12 is rotated. While irradiating the molded body 1 with an ion beam, or as shown in FIG. 3C, a plurality of ion sources 13 are installed obliquely above the multi-axis table 12, and the molded body 1 is irradiated with ions from different directions. Or irradiate. Since the molded body 1 has a three-dimensional shape with projections and depressions, it is difficult to irradiate the surface of the molded body 1 uniformly with an ion beam by irradiation from only one direction. Thus, the surface of the molded body 1 can be uniformly irradiated with an ion beam, and the titanium film 2b in the non-circuit region can be completely removed.

  In order to remove the titanium film 2b in the non-circuit region, in addition to irradiating an ion beam which is an example of dry etching, it is also possible to remove the titanium film 2b by performing a blasting process which is another example of dry etching. For this blast treatment, alumina particles may be used.

6) Nickel / gold plating layer forming step After removing the titanium film 2b in the non-circuit region, as shown in FIG. 2 (c), the copper plating layer 4 is subjected to nickel plating, and further gold plating is performed thereon. Then, the nickel / gold plating layer 5 is formed. Thereby, the three-dimensional circuit board by which the circuit comprised by the titanium film 2a, the copper film 3a, the copper plating layer 4, and the nickel gold plating layer 5 was formed on the surface of the molded object 1 can be manufactured. Various methods such as electroplating and electroless plating can be employed as a method for performing nickel plating and gold plating. In addition, this process can also be abbreviate | omitted depending on the use of a three-dimensional circuit board.

  In the manufacturing method of the present embodiment, since the titanium film 2 is formed between the surface of the molded body 1 and the copper film 3, the copper film 3 and the molded body 1 can be firmly bonded by the titanium film 2, Sufficient adhesion can be obtained. Moreover, titanium does not have an adverse effect on the environment. In the three-dimensional circuit board manufactured by this manufacturing method, circuit components such as ICs, capacitor chips, and resistors are barely mounted on the three-dimensional circuit board, or the three-dimensional circuit board itself is mounted as a package on another motherboard. used. When solder is used for the mounting, thermal stress is generated in the mounting part. However, since the three-dimensional circuit board manufactured by this manufacturing method has sufficient adhesion, it can cope with the thermal stress. You can get it. Moreover, it has excellent heat resistance and environmental resistance as a package, and can be applied as a highly reliable substrate for in-vehicle applications and sensor devices.

  Further, after plating the copper film 3a in the circuit area, the titanium film 2b in the non-circuit area is removed by irradiation with an ion beam, thereby utilizing the film thickness difference between the circuit area and the non-circuit area. The titanium film 2b in the non-circuit region can be completely removed with the copper film 3a and the copper plating layer 4 remaining. And the insulation reliability between circuits can be improved by removing the titanium film 2b.

  Next, with reference to FIG. 4, the manufacturing method of the three-dimensional circuit board based on 2nd Embodiment of this invention is demonstrated. The manufacturing method of this embodiment employs a titanium film oxidation step instead of the titanium film removal step in the manufacturing method of the first embodiment.

  In the titanium film oxidation step, after the titanium film 2b in the non-circuit region is exposed, the titanium film 2b in the non-circuit region is subjected to an oxidation treatment as shown in FIGS. Is a titanium oxide film 2b ′. As the oxidation treatment, plasma treatment is performed in an oxidizing atmosphere, or when the molded body 1 is ceramic or the like and has heat resistance, the molded body 1 may be heated to 200 to 500 ° C. in an oxidizing atmosphere. . Then, as shown in FIG. 4C, a nickel / gold plating layer forming step is performed.

  As described above, since the titanium film 2b in the non-circuit region can be made non-conductive by using the titanium oxide film 2b 'as the titanium film 2b', the insulation reliability between circuits can be obtained without removing the titanium film 2b in the non-circuit region. Can be improved.

  Next, with reference to FIG. 5, the manufacturing method of the three-dimensional circuit board based on 3rd Embodiment of this invention is demonstrated. The manufacturing method of this embodiment replaces the titanium film removal step and the nickel / gold plating layer forming step in the manufacturing method of the first embodiment.

  That is, as shown in FIGS. 5A and 5B, after the titanium film 2b in the non-circuit region is exposed, the copper plating layer 4 is subjected to nickel plating, and further gold plating is applied thereto. After the gold plating layer 5 is formed, the titanium film 2b in the non-circuit region is removed as shown in FIG. Finally, the surface of the nickel / gold plating layer 5 is activated by plasma cleaning or the like. In the present manufacturing method, the copper film removing step for exposing the titanium film 2b in the non-circuit region and the nickel / gold plating layer forming step may be further interchanged.

  Thus, since the copper / plated layer 4 is covered with the nickel / gold plated layer 5 by performing the nickel / gold plated film forming step prior to the titanium film removing step, etching using hydrofluoric acid is not performed. The titanium film 2b in the circuit area can be removed. That is, even when etching using hydrofluoric acid is performed, the nickel / gold plating layer 5 can prevent the copper plating layer 4 from being eroded by the etching.

  Next, a method for manufacturing a molded circuit board according to the fourth embodiment of the present invention will be described. The manufacturing method of this embodiment employs a mixed film forming step of titanium and copper in place of the titanium film and copper film forming step in the manufacturing method of each of the above embodiments.

  In the mixed film forming step of the titanium film and copper, the sputtering apparatus 14 shown in FIG. 6 is used. The target 15A of the sputtering apparatus 14 is configured by mixing titanium and copper. The mixing amount of titanium is preferably about 5 to 15 mass percent. Then, by performing sputtering using the target 15A, a mixed film 6 of titanium and copper as shown in FIG.

  Thus, if the mixed film 6 of titanium and copper is formed on the surface of the molded body 1, the bonding strength between the molded body 1 and the mixed film 6 is improved, and sufficient adhesion can be obtained. Moreover, by using the mixed film 6 of titanium and copper, the mixed film 6 in the non-circuit region can be removed by a single etching, and titanium can be easily removed because titanium is mixed in the copper. .

  Further, instead of the target 15A configured by mixing titanium and copper, a target 15B configured by arranging titanium 15a and copper 15b as shown in FIG. 8 may be used. When this target 15B is used, as indicated by an arrow a in the figure, sputtering is performed while conveying the molded body 1 in a direction from the titanium 15a of the target 15B toward the copper 15b. By doing so, as shown in FIG. 9, it is possible to form a mixed film 7 having a composition ratio in which the amount of titanium is large in the vicinity of the surface of the molded body 1 and the amount of copper increases as the distance from the surface increases.

  In this way, since titanium is increased in the vicinity of the surface of the molded body 1, the bonding strength between the molded body 1 and the mixed film 7 is further improved, and sufficient adhesion can be obtained. Moreover, since the mixed film 7 has no interface between titanium and copper, the ratio of copper at the boundary with the copper plating layer 4 can be increased while the strength of the mixed film 7 itself is kept high. The bonding strength with the layer 4 can also be improved.

It is explanatory drawing of the manufacturing method of the three-dimensional circuit board which concerns on 1st Embodiment of this invention. It is explanatory drawing of the manufacturing method of the three-dimensional circuit board which concerns on 1st Embodiment of this invention. It is explanatory drawing when irradiating an ion beam to a molded object using a multi-axis table. It is explanatory drawing of the manufacturing method of the molded circuit board which concerns on 2nd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the three-dimensional circuit board which concerns on 3rd Embodiment of this invention. It is explanatory drawing of the manufacturing method of the three-dimensional circuit board which concerns on 4th Embodiment of this invention. It is a cross-sectional front view of the mixed film part formed with the manufacturing method of 4th Embodiment. It is explanatory drawing of the manufacturing method of the molded circuit board which concerns on the modification of 4th Embodiment. It is a cross-sectional front view of the mixed film part formed with the manufacturing method of the modification of 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molded body 2 Titanium film 2a Titanium film in circuit area 2b Titanium film in non-circuit area 3 Copper film 3a Copper film in circuit area 3b Copper film in non-circuit area 4 Copper plating layer 5 Nickel / gold plating layer 14 Sputtering device 15A, 15B target

Claims (7)

Forming a titanium film on the surface of the molded body having a three-dimensional shape, and further forming a copper film thereon;
Irradiating the copper film with electromagnetic waves along a boundary line between a circuit region constituting a circuit and a non-circuit region not constituting a circuit, and removing the copper film and the titanium film on the boundary line;
And a step of performing copper plating on the copper film in the circuit region to form a copper plating layer.   The method further comprises a step of exposing the titanium film by removing the copper film in the non-circuit region and a step of oxidizing the titanium film in the non-circuit region to make the titanium film a titanium oxide film. The manufacturing method of the three-dimensional circuit board of Claim 1.   Removing the copper film in the non-circuit area and exposing the titanium film; forming the copper plating layer; exposing the titanium film in the non-circuit area; and irradiating the circuit area and the non-circuit area with an ion beam. The method for manufacturing a three-dimensional circuit board according to claim 1, further comprising a step of removing the titanium film in the non-circuit region.   Removing the copper film in the non-circuit region and exposing the titanium film; forming the copper plating layer; exposing the titanium film in the non-circuit region; and performing blasting to perform a titanium film in the non-circuit region The method of manufacturing a three-dimensional circuit board according to claim 1, further comprising:   Removing the copper film in the non-circuit region and exposing the titanium film; applying nickel plating to the copper plating layer; further applying gold plating thereon to form a nickel / gold plating layer; The method for manufacturing a three-dimensional circuit board according to claim 1, further comprising a step of performing etching to remove the titanium film in the non-circuit region after forming the nickel / gold plating layer. Forming a mixed film of titanium and copper on the surface of a molded article having a three-dimensional shape by performing sputtering using a target composed of titanium and copper; and
Irradiating the mixed film with electromagnetic waves along a boundary line between a circuit region constituting a circuit and a non-circuit region not constituting a circuit, and removing the mixed film on the boundary line;
And a step of forming a copper plating layer by performing copper plating on the mixed film in the circuit region. Using a target composed of titanium and copper arranged side by side, sputtering is performed while transporting a molded body having a three-dimensional shape in the direction from the target titanium to copper, thereby forming a mixed film of titanium and copper on the surface of the molded body. Forming a step;
Irradiating the mixed film with electromagnetic waves along a boundary line between a circuit region constituting a circuit and a non-circuit region not constituting a circuit, and removing the mixed film on the boundary line;
And a step of forming a copper plating layer by performing copper plating on the mixed film in the circuit region.

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