JP2020010179A - Manufacturing method of high-frequency passive component - Google Patents

Abstract

To provide a manufacturing method of a high-frequency passive component, capable of improving a manufacturing cost and a mass productivity.SOLUTION: A manufacturing method of a high-frequency passive component, having a substrate 35 formed by a dielectric body, and a side wall or a penetration electrode 45 formed in the substrate 35, comprises: a step of manufacturing an original mold having a concave part corresponding to the side wall or the penetration electrode 45 from a glass; a step of manufacturing a mold having a convex part corresponding to the concave part from a metal by using the original mold; a step of manufacturing the substrate 35 having the concave part corresponding to the convex part from a resin by using the mold; a step of polishing a surface 34 opposite to the side where the concave part 31 of the substrate 35 is opened to expose the concave part 31 to a surface 36 on the opposite side; and a step of forming a conductive layer 41 formed by the side wall or the penetration electrode 45 in the concave part 31 after it is exposed or was exposed to the surface 36 of the opposite side.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for manufacturing a high-frequency passive component having a waveguide structure that can be used for high-frequency communication such as millimeter waves.

  In recent years, high-speed, large-capacity communication of several gigabits per second (bps) using a millimeter wave band has been proposed, and a part thereof is being realized. As a mode for realizing a small and inexpensive millimeter-wave communication module, for example, Patent Document 1 proposes a mode converter using a post-wall waveguide (Post-wall Waveguide).

JP 2014-158243 A

  Patent Literature 1 discloses a glass substrate, a quartz substrate, or the like as a substrate used for manufacturing a precise passive component. However, glass substrates, quartz substrates, and the like are difficult to process and take time, and thus have problems of manufacturing cost and mass productivity.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of manufacturing a high-frequency passive component capable of improving manufacturing cost and mass productivity.

  In order to solve the above-mentioned problem, the present invention is a method for manufacturing a high-frequency passive component having a substrate made of a dielectric, and a side wall and / or a through electrode formed on the substrate. A step of manufacturing a mold having a corresponding concave portion from glass, a step of using a mold to form a mold having a convex portion corresponding to the concave portion from a metal, and using the mold to correspond to the convex portion. Manufacturing a substrate having a concave portion from a resin, polishing the surface of the substrate opposite to the side on which the concave portion opens, and exposing the concave portion to the opposite surface; and Forming a conductor layer serving as a side wall and / or a through electrode in the concave portion or the concave portion exposed on the opposite surface of the substrate.

  Femtosecond laser-assisted etching may be used in the step of manufacturing a mold having a concave portion corresponding to the side wall and / or the through electrode from glass.

Forming a conductive layer on the side of the substrate having the concave portion where the concave portion opens, and forming a conductive layer on the opposite surface after the step of exposing the concave portion to the opposite surface. And may be provided.
Prior to the step of exposing the concave portion to the opposite surface, a step of forming a conductor layer on the side of the substrate having the concave portion where the concave portion opens, and a conductor formed on the side where the concave portion opens Covering the layer with an insulating material.

Prior to the step of exposing the concave portion to the opposite surface, a step of forming a conductor layer serving as a side wall and / or a through electrode in the concave portion of the substrate is provided, and the concave portion is formed on the opposite surface. In the exposing step, the conductor layer formed in the concave portion may be exposed on the opposite surface to serve as a side wall and / or a through electrode.
The high-frequency passive component may have a waveguide structure configured to surround a waveguide region by conductor layers formed on both surfaces of the substrate and side walls or through electrodes connected to the conductor layers.

  Bonding the substrate to another wiring substrate, forming a communication hole penetrating the substrate and the other wiring substrate, forming a connection conductor in the communication hole, and forming the connection hole on the substrate. Electrically connecting the high-frequency passive component to the wiring of the another wiring board.

  ADVANTAGE OF THE INVENTION According to this invention, precise processing is possible using a glass prototype as a master, a metal mold is produced in a desired number from the master, and a resin on which precise side walls and / or through electrodes are formed using the mold. Substrates can be manufactured at low cost and at low cost, and are excellent in mass productivity.

It is sectional drawing which shows the process of producing a type | mold from a prototype in order of (a)-(c). It is sectional drawing which shows the process of producing a board | substrate from a type | mold in order of (a)-(c). It is sectional drawing which shows the process of manufacturing a high frequency passive component in order of (a)-(d). It is sectional drawing which shows the process of joining a board | substrate with a wiring board in order of (a)-(b).

  Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings. 1 (a) to 1 (c) sequentially show steps of producing a mold from a prototype. FIGS. 2A to 2C sequentially show steps of manufacturing a substrate from a mold. FIGS. 3A to 3D sequentially show steps of manufacturing a high-frequency passive component on a substrate. FIGS. 4A and 4B show a process of joining a substrate on which a high-frequency passive component is manufactured to another wiring substrate.

  The method of manufacturing the high-frequency passive component according to the present embodiment generally includes, as shown in FIG. 1, a step of manufacturing a mold 10 having a concave portion 11 corresponding to a side wall or a through electrode and a concave portion 12 corresponding to a through electrode from glass. Forming a mold 20 having projections 21 and 22 corresponding to the recesses 11 and 12 of the mold 10 from a metal using the mold 10, and forming the mold 20 using the mold 20 as shown in FIG. 2. The step of manufacturing the substrate 35 having the concave portions 31 and 32 corresponding to the convex portions 21 and 22 from the substrate material 30 made of resin is opposite to the side of the substrate 35 where the concave portions 31 and 32 are opened as shown in FIG. Polishing the second main surface 34 on the side to expose the concave portions 31 and 32 of the substrate 35 to the second main surface 34. The substrate 35 can be provided with side walls or through electrodes 45 and through electrodes 46.

  As shown in FIG. 1A, the prototype 10 has a first main surface 13 in which the concave portions 11 and 12 are open, and a second main surface 14 on the opposite side to the first main surface 13. The recesses 11 and 12 do not reach the second main surface 14 and the bottoms are closed. In the present embodiment, the prototype 10 has the same shape as the substrate 35, and is used to transfer the shape of the prototype 10 to the mold 20, and further to transfer the shape of the mold 20 to the substrate material 30. That is, the prototype 10 is not a mold 20 for directly molding the substrate 35 but a master mold that is a base of the mold 20.

  Glass is mentioned as a dielectric material constituting the prototype 10. Examples of the glass include multi-component glass, quartz glass (silica glass), and silicate glass. As a material similar to glass, inorganic materials such as sapphire, synthetic quartz, natural quartz, and semiconductors can be used. The dielectric substrate constituting the prototype 10 may be, for example, a wafer-shaped large-area substrate. In FIG. 1, the concave portions 11 and 12 of the prototype 10 are shown facing downward, but the prototype 10 may be arranged in a direction different from the downward direction.

  Examples of a method for forming the concave portions 11 and 12 in the prototype 10 include a drilling machine such as a drill, laser, and etching. For example, there is a method in which a material such as glass is locally modified by condensing irradiation of a laser, and a portion having increased solubility due to the modification is selectively removed by wet etching. For example, femtosecond laser-assisted etching enables processing with high positional accuracy and high processing accuracy. The femtosecond laser-assisted etching referred to here means, first, to provide a modified part consisting of cracks or structurally modified parts along the condensing part by condensing and scanning an ultrashort pulse laser with a pulse width of 10 ps or less. Next, a processing method in which the modified portion is selectively etched by etching to provide the concave portions 11 and 12 and the like. Not only can micropores having a high aspect ratio (ratio of depth to diameter) be formed, but also concave portions of any shape including a tapered shape, a stepped shape, and the like can be processed. The tapered shape may have a smaller diameter or shape from the first main surface of the material to the second main surface or inside, or conversely, may have a larger diameter or shape.

  As shown in FIG. 1B, the metal is adhered to the concave portions 11 and 12 and the first main surface 13 of the prototype 10 by electroforming, plating, or the like using a metal such as Ni to form the mold 20. The protrusions 21 and 22 are made of metal deposited on the recesses 11 and 12 of the prototype 10, and the base 23 is made of metal deposited on the first main surface 13 of the prototype 10. By peeling the prototype 10 and the mold 20, as shown in FIG. 1C, the mold 20 in which the protrusions 21 and 22 project from one surface of the base 23 is obtained. Since the material constituting the prototype 10 is excellent in durability, the process of manufacturing the mold 20 from the prototype 10 using the same prototype 10 can be repeated a plurality of times.

  As shown in FIG. 2A, a substrate material 30 made of resin is prepared, and as shown in FIG. 2B, the substrate material 30 is overlaid on the projections 21 and 22 of the mold 20. Substrate material 30 may be a flat film, sheet, or the like. Preferred resins for the substrate material 30 include cycloolefin copolymer (COC), fluororesin, liquid crystal polymer (LCP), and the like. Although the protrusions 21 and 22 of the mold 20 are displayed upward in FIG. 2, the mold 20 may be arranged in a different direction from the upward.

  When the resin constituting the substrate material 30 is a thermoplastic resin, the resin is softened by heating, the shape of the mold 20 is transferred to the substrate material 30 by the hot embossing method, and the concave portions having the shapes corresponding to the convex portions 21 and 22 are formed. 31, 32 can be formed. When the substrate material 30 is a curable resin such as a thermosetting resin or a photocurable resin, the substrate material 30 is applied to the mold 20 in an uncured state having fluidity such as a liquid, and is superimposed on the mold 20. By curing the resin as it is, the concave portions 31 and 32 having shapes corresponding to the convex portions 21 and 22 can be formed.

  By peeling the mold 20 and the substrate material 30, as shown in FIG. 2C, a substrate 35 having the concave portions 31 and 32 formed in the first main surface 33 in contact with the base 23 of the mold 20 is obtained. . The first main surface 33 is a surface on the side where the concave portions 31 and 32 are opened. The second main surface 34 is a surface opposite to the first main surface 33. The recesses 31 and 32 do not reach the second main surface 34 and are closed at the bottom. Since the material forming the mold 20 is excellent in durability, the process of forming the substrate 35 having the concave portions 31 and 32 using the same mold 20 can be repeated a plurality of times.

  As shown in FIG. 3A, first conductor layers 41, 42, 43 are formed on the first main surface 33 side with respect to the substrate 35 having the concave portions 31, 32 opened in the first main surface 33. Of these, the first conductor layer 41 is formed on the inner wall of the recess 31, the first conductor layer 42 is formed on the inner wall of the recess 32, and the first conductor layer 43 is formed on the first main surface 33. The first conductor layers 41 and 42 formed on the inner walls of the concave portions 31 and 32 are not exposed on the second main surface 34 of the substrate 35. The first conductor layer 42 forms a blind via. The first conductor layer 41 forms a blind via when the concave portion 31 has a hole shape. The first conductor layer 41 forms a continuous side wall 45 when the concave portion 31 has a continuous groove shape along the waveguide structure 48 shown in FIG. The range in which the groove-shaped concave portion 31 or the side wall 45 is continuous is not particularly limited as long as it is at least a part in the longitudinal direction or the width direction of the waveguide structure 48, and may be all around the waveguide structure 48.

  Examples of a method for forming a conductor layer such as the first conductor layers 41, 42, and 43 include one or more of sputtering, vapor deposition, electroless plating, electrolytic plating, and conductor paste. Two or more kinds of conductor materials or film forming methods may be used in combination, or two or more kinds of conductors may be laminated to form a conductor layer. When a conductor layer is formed on an insulator, a seed layer having a smaller thickness than a target may be formed by sputtering, vapor deposition, or electroless plating, and then the conductor may be laminated to a target thickness by electrolytic plating. An oxidation preventing layer such as NiAu, NiPdAu may be provided on the surfaces of the first conductor layers 41, 42, 43 (the outer surface opposite to the side in contact with the substrate 35) to prevent oxidation. Further, patterning or the like may be appropriately performed so that the first conductor layer 43 has a shape such as a wiring and a pad.

  As shown in FIG. 3B, the first main surface 33 of the substrate 35 in which the first conductor layer 43 is formed on the first main surface 33 is covered with an insulating material 44. The insulating material 44 may be filled in the recesses 31 and 32. Examples of the insulating material 44 include a resin. Thus, as described later, when the second main surface 34 of the substrate 35 is polished, the first conductor layers 41, 42, and 43 on the first main surface 33 side can be protected. When the first conductor layer 41 serves as a side wall, the second main surface 34 of the substrate 35 is polished, and when the concave portions 31 and 32 are exposed on the second main surface 36 of the substrate 35, Alternatively, it functions as an adhesive and can prevent the waveguide structure 48 from separating from the substrate 35.

  As shown in FIG. 3C, by polishing the second main surface 34 of the substrate 35, the concave portions 31 and 32 are exposed on a new second main surface 36. In addition, the first conductor layers 41 and 42 formed in the concave portions 31 and 32 are exposed on the new second main surface 36 to become side walls or through electrodes 45 and through electrodes 46. The shapes of the side wall or through electrode 45 and the through electrode 46 are based on the shapes of the precisely formed recesses 31 and 32 according to the shapes of the recesses 11 and 12 of the prototype 10, respectively. Thereby, highly accurate side walls and through holes can be formed in the substrate 35 made of resin.

  As shown in FIG. 3D, a second conductor layer 47 is formed on the second main surface 36 of the substrate 35. The method of forming the second conductor layer 47 may be the same as the method of forming the first conductor layers 41, 42, and 43, as described above. Further, as described above, an oxidation preventing layer may be provided on the surface of the second conductor layer 47 (the outer surface opposite to the side in contact with the substrate 35), and the second conductor layer 47 may be appropriately patterned. Good. The second conductor layer 47 formed on the second main surface 36 may be the same as or different from the first conductor layer 43 formed on the first main surface 33 with respect to the layer configuration, patterning, and the like. .

  As a method of forming a patterned conductor layer using a patterned resist, (1) a conductor layer is formed after a patterned resist is formed, and the conductor layer laminated on the resist is removed together with the resist. Then, a method of leaving a conductor layer in a region where there is no resist (lift-off), or (2) forming a patterned resist on the entire surface of the conductor layer and then forming a material layer in a region not covered with the resist Is removed by etching or the like, and if necessary, unnecessary resist is removed. The etching method can be appropriately selected from various types such as dry etching and wet etching.

  The side wall or the penetrating electrode 45 and the penetrating electrode 46 formed on the substrate 35 may constitute a passive component (passive device) such as a waveguide, a filter, a diplexer, a directional coupler, and a distributor. For example, when the dielectric constituting the substrate 35 has a region surrounded by the first conductor layer 43, the second conductor layer 47, and the side wall 45, a waveguide structure 48 similar to a waveguide may be constituted. it can. This waveguide structure can be used as a high-frequency device through which a high-frequency signal (electromagnetic wave) such as a millimeter wave is propagated. Although the frequency is not particularly limited, for example, 30 to 300 GHz, 60 to 80 GHz, and the like are exemplified.

  As a waveguide structure including a conductor layer and a through electrode, for example, a post-wall waveguide is given. A wide wall that is grounded by being connected to a ground potential, for example, may be provided on both main surfaces of the substrate that forms the post wall waveguide. The through electrodes can form a wall surrounding the waveguide structure by, for example, arranging a large number of the through electrodes. Examples of the wall formed by the through electrode include a narrow wall facing the width direction of the waveguide structure, a short wall provided at an end in the longitudinal direction, and other side walls. The shape of the through electrode forming the wall is not limited to a cylindrical shape as shown in FIG. 3, but may be a cylindrical shape or the like. In addition, the arrangement of the through electrodes can be variously configured in accordance with the function of the passive component and the like, and the portions where the through electrodes are arranged at equal intervals, the portions where the intervals between the through electrodes are uneven, and the through electrodes A portion that is not arranged over a section may be provided.

  The through electrode 46 provided inside the waveguide structure 48 may constitute a mode conversion mechanism. The mode conversion mechanism is connected to a wiring layer (not shown) provided outside the waveguide structure 48, and inputs an electric signal from the wiring layer to the waveguide structure, or inputs a signal from the waveguide structure to the wiring layer. To output electrical signals.

  As shown in FIG. 3D, in the case of a substrate 35 having passive components such as the waveguide structure 48, when the substrate 35 has a plurality of passive components mounted thereon, individual pieces for cutting the substrate for each passive component are provided. May be included. Examples of the means for cutting the substrate include known processing means such as a blade dicer and a laser.

  FIG. 4 shows an example of a process of joining the passive component 40 having the waveguide structure 48 formed on the substrate 35 to the wiring substrate 50. The wiring board 50 has a wiring layer 52 on at least one surface of an insulating base material 51. In the case of FIG. 4A, the second conductor layer 47 of the passive component 40 is overlaid on the side facing the wiring board 50. The wiring layer 52 on the side facing the passive component 40 is provided with an insulating layer 53 for protecting the wiring layer 52 and the like. Thus, a structure in which the insulating layer 53 is interposed between the second conductor layer 47 and the wiring layer 52 is obtained. The joining method between the passive component 40 and the wiring board 50 is not particularly limited, and examples thereof include an adhesive, soldering, and a mechanical structure such as fitting or engaging.

  When the passive component 40 is electrically connected to the wiring board 50, for example, as shown in FIG. 4B, after forming a communication hole 55 penetrating the passive component 40 and the wiring board 50, electroless plating is performed. For example, the connection conductor 54 may be formed in the communication hole 55. Thereby, the waveguide structure 48 formed on the substrate 35 and the wiring layer 52 of the wiring substrate 50 can be electrically connected. The connection conductor 54 and the communication hole 55 may penetrate the second conductor layer 47 and may be arranged between the side walls 45 or in the insulating material 44 inside the through electrode 45. Means for forming the communication hole 55 is not particularly limited, and examples thereof include a drilling machine such as a drill and a laser.

  As described above, the present invention has been described based on the preferred embodiments. However, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the gist of the present invention. Modifications include addition, substitution, omission, and other changes of the components in each embodiment.

  The method of providing the through electrode in the through hole is not limited to the method of forming the conductor layer in the concave portion before polishing the second main surface of the substrate as in the above-described embodiment. For example, after the second main surface of the substrate is polished to form a through hole in the substrate, a conductor layer may be formed in the through hole.

  In the high-frequency passive component according to the above-described embodiment, a plurality of components may be configured on the same substrate. Other components configured on the substrate are not limited to high-frequency passive components, and may include other passive components, active components, and the like. By modularizing the components, a high-frequency module can be configured. The high-frequency module of the present embodiment is, for example, a module including the above-described high-frequency passive component. Various components necessary for the function can be incorporated in the module.

Reference numerals 10: prototype, 11, 12: prototype recess, 20: mold, 21, 22, ... projection, 30: substrate material, 31, 32: recess, 35: substrate, 40: passive component, 41, 42, 43 .. 1st conductor layer, 44 ... insulating material, 45 ... side wall or through electrode, 46 ... through electrode, 47 ... second conductor layer, 48 ... waveguide structure, 50 ... wiring board, 52 ... wiring layer, 54 ... connection conductor , 55 ... communication holes.

Claims (7)

A method for manufacturing a high-frequency passive component having a substrate made of a dielectric and side walls and / or through electrodes formed on the substrate,
Manufacturing a mold having a concave portion corresponding to a side wall and / or a through electrode from glass;
Using the prototype, forming a mold having a projection corresponding to the recess from metal,
Using the mold, a step of manufacturing a substrate having a concave portion corresponding to the convex portion from a resin,
Polishing the surface of the substrate opposite to the side where the concave portion is opened, and exposing the concave portion to the opposite surface;
Forming a conductor layer serving as a side wall and / or a through electrode in the concave portion of the substrate or the concave portion exposed on the opposite surface of the substrate;
A method for manufacturing a high-frequency passive component, comprising:   2. The method of manufacturing a high-frequency passive component according to claim 1, wherein femtosecond laser-assisted etching is used in the step of manufacturing a mold having a concave portion corresponding to the side wall and / or the through electrode from glass. 3. Forming a conductor layer on the side of the substrate having the concave portion where the concave portion opens,
After the step of exposing the recess on the opposite surface, a step of forming a conductor layer on the opposite surface,
The method for manufacturing a high-frequency passive component according to claim 1, wherein: Prior to the step of exposing the concave portion to the opposite surface,
Forming a conductor layer on the side of the substrate having the concave portion where the concave portion opens,
A step of covering the conductor layer formed on the side where the concave portion opens with an insulating material,
The method for manufacturing a high-frequency passive component according to any one of claims 1 to 3, further comprising: Prior to the step of exposing the concave portion to the opposite surface, a step of forming a conductor layer serving as a side wall and / or a through electrode in the concave portion of the substrate;
In the step of exposing the concave portion on the opposite surface, the conductor layer formed in the concave portion is exposed on the opposite surface to form a side wall and / or a through electrode. The method for manufacturing a high-frequency passive component according to any one of claims 1 to 4.   The high-frequency passive component has a waveguide structure configured to surround a waveguide region by a conductor layer formed on both surfaces of the substrate and a side wall or a through electrode connected to the conductor layer. A method for manufacturing the high-frequency passive component according to claim 1. Bonding the substrate to another wiring board;
Forming a communication hole penetrating the substrate and the other wiring board,
Forming a connection conductor in the communication hole, and electrically connecting a high-frequency passive component formed on the substrate and the wiring of the other wiring substrate,
The method for manufacturing a high-frequency passive component according to any one of claims 3 to 6, comprising:

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