Method for manufacturing a package

Abstract

A ceramic substrate part (110) provided with a substrate wiring part (200) is formed as a substrate green body (GS). A ceramic frame part (120) is formed as a frame-shaped green sheet (GF) having a frame shape surrounding a cavity (CV). The frame-shaped green sheet (GF) is layered onto the substrate green body (GS). A via hole (VH) that reaches the substrate wiring part (200) without penetrating the substrate wiring part (200) is formed in the frame-shaped green sheet (GF) by laser processing. A via electrode (510) is formed inside the via hole (VH) of the frame-shaped green sheet (GF) as an electrode green body (G510). The substrate green body (GS), the frame-shaped green sheet (GF), and the electrode green body (G510) are fired.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a package, and more particularly to a method for manufacturing a package having a ceramic frame portion provided with via electrodes.

Background Art

[0002] As a ceramic component manufactured using a ceramic green sheet, a package for a crystal oscillator is known. A general crystal oscillator has a crystal blank, a package having a cavity in which the crystal blank is housed, and a lid for sealing the cavity. The package has a substrate portion forming the bottom surface of the cavity, a frame portion surrounding the cavity, and a metallized layer provided on this frame portion. The lid is joined to the metallized layer using a joining material (typically, a brazing material).

[0003] The metallized layer on the frame portion of the package is usually electrically short-circuited to an electrode pad for ground potential. This electrical path is typically ensured via a via electrode that penetrates the frame portion. However, as the package is miniaturized, the material width of the frame portion (the dimension between the inner wall surface and the outer wall surface of the frame portion) has become smaller, and it has become difficult to form corresponding fine via electrodes. Specifically, it has become difficult to form fine via holes for fine via electrodes in the green sheet that becomes the frame portion by firing. As a typical method for forming via holes, when a mold having a pin shape is used, if the pin shape is miniaturized to miniaturize the via holes, the mechanical strength of the pin is likely to be insufficient. Therefore, in mold processing, as the via holes become finer, it has become difficult to ensure the processing efficiency in mass production.

[0004] For example, according to the technology disclosed in Japanese Patent Application Laid-Open No. 2007-27592 (Patent Document 1), instead of via electrodes, a castellated electrode having a substantially crescent shape is provided on the inner wall surface of the frame portion. However, when a castellated electrode is provided on the side wall of the cavity instead of a via electrode as in the technology of the above publication, in the step of joining the lid using a brazing material, the brazing material easily flows into the cavity along the castellated electrode. When the flowed-in brazing material comes into contact with the crystal blank, it may have an adverse effect on the performance of the crystal oscillator. Note that the adverse effect on the mechanical properties due to the inflow of the brazing material is particularly a concern when the element mounted on the package is a crystal blank, but it may also occur in the case of other piezoelectric elements as well as crystal blanks. Furthermore, not only for piezoelectric elements but also for other electronic components, there is a concern about an adverse effect on the electrical properties, such as an unintentional short circuit.

[0005] Japanese Patent Application Laid-Open No. 2009-234074 (Patent Document 2) discloses a method of forming minute through holes as via holes in a ceramic green sheet by a laser processing technique. Specifically, through holes having a diameter of 30 μm to 50 μm are formed in a ceramic green sheet having a thickness of 250 μm or less using an ultraviolet laser. By using such laser processing instead of the above-described die processing, it is possible to ensure the processing efficiency of via holes in mass production of small packages.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] Although the processing efficiency of via holes can be increased by using laser processing as described above, a method for ensuring the processing position accuracy of via holes has not been sufficiently studied so far. With the progress of miniaturization of packages, it is required to further improve the processing position accuracy of via holes. As the position accuracy of via holes, firstly, the position accuracy with respect to the cavity is required. If the misalignment is excessive, the dimensions of the frame portion surrounding the via hole may become too small, and in extreme cases, defects may occur due to the processing of the via hole being out of the frame. As the position accuracy of via holes, secondly, the position accuracy with respect to the wiring portion provided on the substrate portion is required. This is because the purpose of the via electrode to be provided in the via hole is to obtain electrical connection with the wiring portion on the substrate portion. As described above, the via hole needs to have position accuracy in the package, specifically, position accuracy with respect to each of the cavity and the wiring portion.

[0008] The present invention has been made to solve the above problems, and an object thereof is to provide a method for manufacturing a package capable of improving the position accuracy of via holes in the package.

Means for Solving the Problems

[0009] A method for manufacturing a package according to one aspect is a method for manufacturing a package provided with a cavity for housing an electronic component. The package includes a ceramic substrate portion, a substrate wiring portion provided on the ceramic substrate portion, a ceramic frame portion disposed on the ceramic substrate portion provided with the substrate wiring portion and surrounding the cavity, and a via electrode provided on the ceramic frame portion and reaching the substrate wiring portion. The manufacturing method includes a step of forming the ceramic substrate portion provided with the substrate wiring portion as a green ceramic substrate, a step of forming the ceramic frame portion as a frame-shaped green sheet having a frame shape surrounding the cavity, a step of laminating the frame-shaped green sheet on the green ceramic substrate, a step of forming via holes in the frame-shaped green sheet that reach the substrate wiring portion without penetrating the substrate wiring portion by performing laser processing, a step of forming the via electrode as an electrode green body in the via holes of the frame-shaped green sheet, and a step of firing the green ceramic substrate, the frame-shaped green sheet, and the electrode green body.

[0010] The step of forming the via holes may include a step of recognizing the position of the cavity in the frame-shaped green sheet and a step of determining a position where the laser processing is to be performed based on the position recognized by the step of recognizing the position of the cavity in the frame-shaped green sheet.

[0011] Define the processing rate ratio of the laser light as the ratio of the processing rate of the laser light for the material of the substrate wiring portion in the green ceramic substrate to the processing rate of the laser light for the material of the ceramic frame portion in the frame-shaped green sheet. The step of forming the via holes may include a step of partially forming the via holes in the frame-shaped green sheet by irradiating laser light with a first processing rate ratio and a step of causing the via holes in the frame-shaped green sheet to reach the substrate wiring portion by irradiating laser light with a second processing rate ratio. The second processing rate ratio is lower than the first processing rate ratio.

[0012] The step of forming the via holes may include a step of partially forming the via holes in the frame-shaped green sheet by irradiating the frame-shaped green sheet with pulsed laser light having a first pulse energy, and a step of causing the via holes in the frame-shaped green sheet to reach the substrate wiring portion by irradiating the frame-shaped green sheet with pulsed laser light having a second pulse energy. The second pulse energy is lower than the first pulse energy. The first pulse energy may be 1 mJ or more and 40 mJ or less, and the second pulse energy may be 10 μJ or more and 200 μJ or less.

[0013] The step of forming the via holes may include a step of partially forming the via holes in the frame-shaped green sheet by irradiating the frame-shaped green sheet with laser light having a first wavelength, and a step of causing the via holes in the frame-shaped green sheet to reach the substrate wiring portion by irradiating the frame-shaped green sheet with laser light having a second wavelength. The second wavelength is shorter than the first wavelength. The first wavelength may be 9.4 μm or more and 10.7 μm or less, and the second wavelength may be 343 nm or more and 1064 nm or less.

[0014] A method of manufacturing a package according to another aspect is a method of manufacturing a package provided with a cavity for housing an electronic component. The package includes a ceramic substrate portion, a substrate wiring portion provided on the ceramic substrate portion, a ceramic frame portion disposed on the ceramic substrate portion provided with the substrate wiring portion and surrounding the cavity, and a via electrode provided on the ceramic frame portion and reaching the substrate wiring portion. The manufacturing method includes a step of forming the ceramic substrate portion provided with the substrate wiring portion as a substrate green body, a step of forming the ceramic frame portion as a frame-shaped green sheet having a frame shape surrounding the cavity, a step of laminating the frame-shaped green sheet on the substrate green body, and irradiating the frame-shaped green sheet with CO 2 laser light to form a recess that will later become a via hole in the frame-shaped green sheet, and irradiating the frame-shaped green sheet with CO 2After the step of forming the concave portion by irradiating laser light, a step of forming the via hole that reaches the substrate wiring portion without penetrating the substrate wiring portion in the frame-shaped green sheet by irradiating solid laser light to the concave portion is included. The wavelength of the solid laser light may be shorter than the wavelength of the CO 2 laser light.

Advantages of the Invention

[0015] According to one aspect, a via hole is formed in a frame-shaped green sheet surrounding a cavity on a ceramic substrate portion provided with a substrate wiring portion. Thereby, the via hole can be formed based on the position of the cavity. Therefore, the positional accuracy of the via hole in the package can be improved.

[0016] According to another aspect, the concave portion that will be expanded into the via hole can be efficiently formed by using CO 2 laser light. Then, by using solid laser light to expand the concave portion into a via hole, it becomes easier to accurately stop the formation of the via hole on the substrate wiring portion without penetrating the substrate wiring portion. From the above, it is possible to achieve both sufficient manufacturing efficiency and sufficient manufacturing yield.

[0017] The object, features, aspects, and advantages of this invention will become clearer from the following detailed description and the accompanying drawings.

Brief Description of the Drawings

[0018]

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Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] <Embodiment 1> FIG. 1 is a plan view schematically showing the configuration of the crystal oscillator 900 in the present Embodiment 1. FIG. 2 is a schematic cross-sectional view taken along line II-II of FIG. 1. FIG. 3 is a plan view schematically showing the configuration immediately after the crystal blank 890 (electronic component) is mounted in the manufacturing method of the crystal oscillator 900 (FIG. 1). FIG. 4 is a schematic cross-sectional view taken along line IV-IV of FIG. 3.

[0021] The crystal oscillator 900 includes a package 701, a crystal blank 890, a brazing material 960, and a lid 980. A cavity CV is provided in the package 701. The crystal blank 890 is housed in the cavity CV and mounted on the element electrode pads 211 and 212 of the package 701. The lid 980 is joined to the metallization layer 600 of the package 701 by the brazing material 960, thereby sealing the cavity CV. The brazing material 960 preferably typically consists of an alloy containing gold, for example, an alloy containing gold and tin, in other words, an Au - Sn based alloy. The lid 980 is made of metal, for example, an alloy containing iron and nickel. In this specification, an alloy is regarded as a kind of metal.

[0022] The metallization layer 600 typically consists of a metal containing at least one of molybdenum and tungsten. A plating layer may be provided on the surface of the metallization layer 600 (the surface facing the brazing material 960), and typically a gold plating layer is provided. Also, a nickel plating layer may be provided as an underlayer for the gold plating layer. In this embodiment, the space between the metallization layer 600 directly provided on the upper frame surface SF1 of the ceramic frame portion 120 of the package 701 and the lid 980 is joined only by the brazing material 960.

[0023] FIG. 5 is a plan view schematically showing the configuration of the package 701. FIG. 6 is a schematic cross - sectional view taken along line VI - VI of FIG. 5. The package 701 has a ceramic portion 100, element electrode pads 211, element electrode pads 212, and package electrode pads 301 - 304. Also, although it will be described in detail later, the package 701 has a configuration for electrical wiring provided in the ceramic portion 100.

[0024] The ceramic part 100 is made of ceramic, preferably has an oxide as the main component, more preferably has alumina as the main component, and for example, consists essentially of alumina. The ceramic part 100 includes a ceramic substrate part 110 and a ceramic frame part 120. The material of the ceramic substrate part 110 and the material of the ceramic frame part 120 may be the same. The ceramic frame part 120 is laminated on the ceramic substrate part 110 in the thickness direction (the vertical direction in FIG. 6). Thereby, the ceramic frame part 120 is disposed on the ceramic substrate part 110 and surrounds the cavity CV. The ceramic frame part 120 has a frame upper surface SF1 (the first surface) and a frame lower surface SF2 (the second surface opposite to the first surface in the thickness direction). The ceramic frame part 120 also has an inner wall surface connecting the frame upper surface SF1 and the frame lower surface SF2 to each other, and the inner wall surface is the side wall of the cavity CV. The ceramic substrate part 110 has a substrate upper surface SF3 (the third surface). The substrate upper surface SF3 has a support surface portion SF3S that supports the frame lower surface SF2 of the ceramic frame part 120 and a cavity surface portion SF3C facing the cavity CV. The cavity surface portion SF3C forms the bottom surface of the cavity CV.

[0025] The element electrode pads 211 and 212 (FIG. 5) face the cavity CV and are disposed on the ceramic part 100 (FIG. 6). Specifically, the element electrode pads 211 and 212 are disposed on the cavity surface portion SF3C of the substrate upper surface SF3 of the ceramic substrate part 110 (FIG. 6). The package electrode pads 301 to 304 (FIG. 5) are disposed on the ceramic part 100 (FIG. 6) outside the cavity CV. Specifically, the package electrode pads 301 to 304 are disposed on the lower surface of the ceramic substrate part 110 (FIG. 6) (the surface opposite to the substrate upper surface SF3).

[0026] The relay electrode 220 (Fig. 5) is provided on the upper surface SF3 of the ceramic substrate portion 110 (Fig. 6). The relay electrode 220 is at least partially disposed on the support surface portion SF3S (Fig. 6). Therefore, the relay electrode 220 (Fig. 5) is at least partially covered by the ceramic frame portion 120. The relay electrode 220 may further have a portion disposed on the bottom surface of the cavity CV without being covered by the ceramic frame portion 120. In other words, the relay electrode 220 may be only partially covered by the ceramic frame portion 120.

[0027] Fig. 7 is a plan view with the illustration of the metallization layer 600 in Fig. 5 and the ceramic frame portion 120 provided with the via electrode 510 (see Fig. 9) omitted. Fig. 8 is a plan view schematically showing the ceramic substrate portion 110 and the substrate via electrodes 411 to 414 in Fig. 7 while showing the package electrode pads 301 to 304 by broken lines.

[0028] In the ceramic substrate portion 110 of the ceramic portion 100, wiring layers 401 to 403 are embedded in the vicinity of its upper surface. The wiring layer 401 is in contact with the element electrode pad 211, the wiring layer 402 is in contact with the element electrode pad 212, and the wiring layer 403 is in contact with the relay electrode 220. The wiring layers 401 to 403 may be covered by an insulating film 110i (see Fig. 10) as a part of the ceramic substrate portion 110 as long as these contacts are not inhibited. In particular, between the element electrode pad 211 and the wiring layer 403, they are insulated by the insulating film 110i. The substrate wiring portion 200 is constituted by the wiring layer 403 and the relay electrode 220. The substrate wiring portion 200 is provided on the ceramic substrate portion 110.

[0029] Package 701 has substrate via electrodes 411 to 414 embedded in the ceramic substrate portion 110 of the ceramic portion 100. Substrate via electrode 411 connects wiring layer 402 and package electrode pad 301 to each other. Substrate via electrode 412 connects wiring layer 403 and package electrode pad 302 to each other. Substrate via electrode 413 connects wiring layer 401 and package electrode pad 303 to each other. Substrate via electrode 414 connects wiring layer 403 and package electrode pad 304 to each other.

[0030] From the above configuration, element electrode pad 211 is electrically connected to package electrode pad 303, element electrode pad 212 is electrically connected to package electrode pad 301, and relay electrode 220 is electrically connected to package electrode pad 302 and package electrode pad 304.

[0031] FIG. 9 is a plan view in which the illustration of the metallization layer 600 in FIG. 5 is omitted. FIG. 10 is a schematic partial cross-sectional view taken along line X-X of each of FIGS. 5 and 7 to 9.

[0032] The minimum dimension between the inner wall surface of the ceramic frame portion 120 (the surface facing the cavity CV in FIG. 9) and the outer wall surface SF4 (the surface opposite to the inner wall surface) may be 200 μm or less, and is typically 20 μm or more and 110 μm or less.

[0033] As described above, the substrate wiring portion 200 is formed on the substrate upper surface SF3 of the ceramic substrate portion 110 by the wiring layer 403 and the relay electrode 220. Also, as described above, the ceramic substrate portion 110 has an insulating film 110i (FIG. 10) as a part thereof.

[0034] As a modification, the insulating film 110i may be omitted depending on the package design. Also, the substrate wiring portion 200 may be constituted by only one of the wiring layer 403 and the relay electrode 220. For example, the substrate wiring portion 200 may have the wiring layer 403 while the relay electrode 220 is omitted. In that case, the boundary position between the wiring layer 403 and the insulating film 110i (the right end position of the wiring layer 403 in FIG. 10) may be shifted to the end position of the relay electrode 220 on the support surface portion SF3S (the right end position of the relay electrode 220 in FIG. 10), and the relay electrode 220 may be omitted. Also, the end of the insulating film 110i facing the cavity CV may be deformed so as to reach the ceramic frame portion 120. In that case, the substrate wiring portion 200 may be separated from the cavity CV by the insulating film 110i. Also, the substrate wiring portion 200 typically extends across the support surface portion SF3S and the cavity surface portion SF3C as shown in FIG. 10, but as a modification, it may be arranged only on the support surface portion SF3S. Also, the substrate wiring portion 200 has an end separated from the outer edge of the lower frame surface SF2 of the ceramic frame portion 120 (the right end of the lower frame surface SF2 in FIG. 10) in the present embodiment, but this end may reach the outer edge.

[0035] The package 701 has a via electrode 510 provided in the ceramic frame portion 120. The via electrode 510 penetrates the ceramic frame portion 120 between the upper frame surface SF1 and the lower frame surface SF2. The via electrode 510 has an end face SFA at the upper frame surface SF1 and a bottom face SFB at the lower frame surface SF2. The diameter of the end face SFA of the via electrode 510 may be 50 μm or less. In comparison, the diameter of the bottom face SFB of the via electrode 510 may be smaller. In a plan view, the center position of the end face SFA and the center position of the bottom face SFB may be approximately the same. The shapes of the end face SFA and the bottom face SFB are approximately circular, but these shapes may be slightly different from a geometrically exact circular shape due to some reason (e.g., manufacturing error). In that case, the diameter may be calculated by approximating the circular shape. The thickness of the via electrode 510 (the dimension in the vertical direction in FIG. 10) is, for example, 50 μm or more and 250 μm or less.

[0036] The via electrode 510 reaches the substrate wiring portion 200, specifically, it reaches the relay electrode 220. As described above, the relay electrode 220 is in contact with the wiring layer 403, and the substrate via electrodes 412 and 414 are connected to the wiring layer 403 (FIG. 7). Therefore, the substrate via electrodes 412 and 414 are electrically connected to the via electrode 510. Further, the end face SFA of the via electrode 510 is in contact with the metallization layer 600. Therefore, the metallization layer 600 is electrically connected to the package electrode pads 302 and 304 via the substrate via electrodes 412 and 414 respectively, with reference to FIG. 8.

[0037] FIG. 11 is a flowchart schematically showing a method of manufacturing the package 701 in the first embodiment. FIG. 12 is a plan view schematically showing a step of the method of manufacturing the package in the first embodiment, FIG. 13 is a plan view schematically showing the substrate portion and the substrate via electrodes in FIG. 12, while showing the package electrode pads by dashed lines, and FIG. 14 is a schematic partial cross-sectional view taken along the line XIV-XIV in FIGS. 12 and 13. FIGS. 15 to 21 are partial cross-sectional views schematically showing a step of the method of manufacturing the package in the first embodiment.

[0038] Referring to FIGS. 12 to 14, in step ST100 (FIG. 11), the ceramic substrate portion 110 provided with the substrate wiring portion 200 is formed as a substrate green body GS. In this specification, the "green body" means a structure that becomes a ceramic body by being fired. The green body is typically a powder compact. In order to facilitate powder molding and handling, the green body may contain a glass component and an organic component as additives in addition to the main component. The organic component may contain, for example, polyvinyl butyral or acrylic. The molding method of the green body is arbitrary. For example, a green sheet as a green body is formed by the doctor blade method. Further green bodies may be added onto this green sheet, and this addition is typically performed by printing on the green sheet or by laminating other green sheets. The printing is typically performed by the screen printing method. The main component of the green body that becomes the ceramic portion 100 by being fired may be, for example, alumina powder. The main component of the green body that becomes the substrate wiring portion 200 and the via electrode 510 by being fired may be, for example, tungsten (W) powder, molybdenum (Mo) powder, a mixed powder of W powder and Mo powder, or a W-Mo alloy powder.

[0039] Specifically, first, a green sheet that will become the ceramic substrate portion 110 is formed. By performing the formation of via holes by punching and the printing of electrode paste into the via holes on this green sheet, a green body that will become the substrate via electrodes 411 to 414 is formed. In the electrode paste, for example, at least one of tungsten and molybdenum powders is dispersed. Subsequently, by printing the electrode paste on this green sheet, a green body that will become the wiring layers 401 to 403 is formed. Subsequently, by printing the ceramic paste on this green sheet, a green body that will become the insulating film 110i is formed. Subsequently, by printing the electrode paste on this green sheet, green bodies that will become the element electrode pads 211 and 212 and the relay electrode 220 are formed. Also, at an arbitrary timing after the green body that will become the substrate via electrodes 411 to 414 is formed as described above, by printing the electrode paste on this green sheet, a green body that will become the package electrode pads 301 to 304 is formed.

[0040] Referring to FIGS. 15 and 16, in step ST200 (FIG. 11), the ceramic frame portion 120 is formed as a frame-shaped green sheet GF having a frame shape surrounding the cavity CV. Specifically, first, as shown in FIG. 15, a green sheet that will become the ceramic frame portion 120 is formed. Next, as shown in FIG. 16, the cavity CV is formed by punching. Note that the order of step ST100 and step ST200 (FIG. 11) is arbitrary.

[0041] Referring to FIG. 17, in step ST300 (FIG. 11), the frame-shaped green sheet GF (see FIG. 16) is laminated on the substrate green body GS (see FIG. 14).

[0042] Referring to FIGS. 18 and 19, at step ST400 (FIG. 11), by performing laser processing, via holes VH that reach the substrate wiring portion 200 without penetrating the frame-shaped green sheet GF are formed in the frame-shaped green sheet GF. Here, the thickness of the substrate wiring portion 200 is, for example, 5 μm or more and 20 μm or less. Also, the thickness of the via holes VH is, for example, 50 μm or more and 250 μm or less.

[0043] A laser processing system, which is a system for performing laser processing, includes a table that supports a workpiece on which laser light is to be irradiated, a laser device that irradiates the workpiece with a desired laser light, and a control unit that controls the table and the laser device.

[0044] The laser device includes a laser oscillator, a collimator lens, a mask, a bending mirror, a scan head, a table, and a camera. The laser oscillator is, for example, a CO 2 laser oscillator that generates laser light. The generated laser light is collimated by the collimator lens. The collimated light is made into a laser beam with an adjusted beam width by passing through the mask. The traveling direction of the laser beam may be adjusted by the bending mirror as necessary. The scan head provided with the laser beam condenses the laser beam at a desired position on the workpiece supported by the table. In order to control this position, the scan head may have a galvanometer scanner for adjusting the position where the laser beam is irradiated to an arbitrary position in two dimensions parallel to the table. Also, the scan head may have a condenser lens between the galvanometer scanner and the workpiece in order to condense the laser beam.

[0045] The control unit may be configured by a general computer having an electric circuit. The general computer has a central processing unit (i.e., CPU), a read only memory (i.e., ROM), a random access memory (i.e., RAM), a storage device, an input unit, a display unit, a communication unit, and bus lines connecting these to each other.

[0046] In the present embodiment, step ST400 includes the following steps ST411, ST412, ST421, and ST422.

[0047] In step ST411 (FIG. 11), the position of the cavity CV of the frame-shaped green sheet GF is recognized. Specifically, the laser processing system uses its camera to recognize the position of the cavity CV of the frame-shaped green sheet GF. This recognition may be performed using ordinary image recognition technology.

[0048] In step ST412 (FIG. 11), based on the position recognized in step ST411 (FIG. 11), the position where the laser processing is to be performed is determined. For example, the control unit of the laser processing system determines, from the recognized position, a predetermined relative position as the position where the laser processing is to be performed.

[0049] In steps ST421 and ST422 (FIG. 11), laser processing is performed in two stages using laser light having different characteristics. In this specification, the "processing rate ratio" of the laser light is defined as the ratio of the processing rate for the material of the ceramic frame portion 120 in the frame-shaped green sheet GF to the processing rate for the material of the substrate wiring portion 200 in the substrate green body GS. Note that the processing rate may be evaluated by the degree to which the depth of the hole formed by the processing extends.

[0050] In the above step ST421 (FIG. 11), by irradiating laser light with a first processing rate ratio, via holes VH (see FIG. 19) of the frame-shaped green sheet GF are partially formed. In other words, as shown in FIG. 18, non-through holes VHp (recesses) are formed in the frame-shaped green sheet GF. The non-through holes VHp (FIG. 18) are incomplete via holes VH (FIG. 19). In other words, the non-through holes VHp will later become via holes VH by being extended. Specifically, the non-through holes VHp (FIG. 18) do not completely penetrate the ceramic frame portion 120. Therefore, a ceramic frame portion 120 that needs to be further removed remains between the bottom surface SHp of the non-through hole VHp and the substrate wiring portion 200.

[0051] In the above step ST422 (FIG. 11), by irradiating the non-through holes VHp (FIG. 18) with laser light having a second processing rate ratio, as shown in FIG. 19, the via holes VH of the frame-shaped green sheet GF are made to reach the substrate wiring portion 200 without penetrating the substrate wiring portion 200. Therefore, the bottom surface SH of the via hole VH is located on the substrate wiring portion 200. In this step ST422, the substrate wiring portion 200 may be slightly removed, but as described above, the via hole VH does not penetrate the substrate wiring portion 200.

[0052] The second processing rate ratio used in step ST422 is lower than the first processing rate ratio used in step ST421. For example, the second processing rate ratio is 0.1% or more and 10% or less of the first processing rate ratio. The first example of the factor for determining the processing rate ratio is the intensity of the laser beam. This is because when the intensity is decreased, the decrease in the processing rate for the material of the substrate wiring portion 200 in the substrate green body GS becomes more prominent than the decrease in the processing rate for the material of the ceramic frame portion 120 in the frame-shaped green sheet GF. This is because the material of the substrate wiring portion 200 in the substrate green body GS generally contains a large amount of a metal material which is a material with a high reflectivity. When the intensity of the laser beam is decreased in a state where the temperature increase effect by the laser beam is originally suppressed due to the high reflectivity, the temperature tends to become insufficient to advance the processing at high speed. Thus, the processing rate ratio in laser processing has a characteristic of being strongly affected by the reflectivity, and the processing rate ratio can be adjusted by utilizing this characteristic. The second example is the wavelength of the laser beam. This is because the absorption rate of the laser beam differs depending on the material. These examples will be described in more detail in Embodiments 2 and 3 described later.

[0053] Referring further to FIG. 20, in step ST500 (FIG. 11), a via electrode 510 (see FIG. 10) is formed as an electrode green body G510 in a via hole VH (FIG. 19) of the frame-shaped green sheet GF. The electrode green body G510 is a green body that becomes the via electrode 510 (see FIG. 10) by being fired. The electrode green body G510 may be formed by filling an electrode paste into the via hole VH by screen printing.

[0054] Referring to FIG. 21, a metallization layer (see FIG. 10) is formed as a metallization green body G600. The metallization green body G600 is a green body that becomes the metallization layer 600 (see FIG. 10) by being fired. The metallization green body G600 is formed by applying an electrode paste, and the application is performed, for example, by a screen printing method.

[0055] In step ST600 (FIG. 11), the substrate green body GS, the frame-shaped green sheet GF, the electrode green body G510, and the metallized green body G600 are fired. Optionally, a plating process may be performed after firing. Thus, the package 701 (FIG. 10) is obtained.

[0056] In the description with reference to FIGS. 12 to 21 above, for the sake of simplicity, a method for manufacturing one package has been described. On the other hand, for efficient mass production, after a sintered body having a structure in which a plurality of packages are connected to each other in the in-plane direction is formed, obtaining a plurality of packages by dividing the sintered body is a well-known technique, and it may be applied to this embodiment. In that case, the outer wall surface SF4 of the package 701 may be formed by a dividing process after firing.

[0057] FIGS. 22 to 25 are partial cross-sectional views showing a method for forming the frame-shaped green sheet GFc in the first comparative example. Referring to FIG. 22, via holes VH are formed before the cavity CV (see FIG. 16) is formed. Further referring to FIG. 23, via electrodes 510 (see FIG. 10) are formed as the electrode green body G510 in the via holes VH (FIG. 22). Referring to FIG. 24, a metallized layer (see FIG. 10) is formed as the metallized green body G600. Referring to FIG. 25, next, the cavity CV is formed. At this time, unnecessary portions of the metallized green body G600 are removed. Thus, the frame-shaped green sheet GFc is formed. This frame-shaped green sheet GFc (FIG. 25) is laminated on the substrate green body GS (see FIG. 14). Thereby, a configuration similar to FIG. 21 in the first embodiment is obtained. However, in this comparative example, when forming the via holes VH, the position of the cavity CV cannot be used as a reference. As a result, it is difficult to sufficiently ensure the positional accuracy of the via holes VH with respect to each of the cavity CV and the substrate wiring portion 200.

[0058] FIG. 26 is a partial cross-sectional view schematically showing a step of a method for manufacturing a package in a second comparative example. In this comparative example, as a result of laser processing, unlike the configuration shown in FIG. 19 in the first embodiment, the bottom surface STt of the via hole VHt penetrates the substrate wiring portion 200. The subsequent steps are the same as the manufacturing method in the first embodiment. FIG. 27 is a partial cross-sectional view schematically showing the configuration of the package 701t in this comparative example. Due to the above-described laser processing, the via electrode 510t in this comparative example penetrates the substrate wiring portion 200, and as a result, the bottom surface SFB of the via electrode 510t is located deeper (downward in the figure) than the substrate wiring portion 200. In the firing step in this comparative example, as indicated by the arrow in FIG. 27, the substrate wiring portion 200 is likely to be pulled away from the via electrode 510t. This is because the coefficient of thermal expansion of the substrate wiring portion 200 is lower than that of the surrounding insulating ceramic portion (typically an alumina ceramic portion). When a disconnection portion BK is generated due to this pulling, a poor electrical connection occurs between the via electrode 510t and the substrate wiring portion 200.

[0059] According to the present embodiment, as shown in FIG. 19, a via hole VH is formed in a frame-shaped green sheet GF surrounding the cavity CV on the ceramic substrate portion 110 provided with the substrate wiring portion 200. Thereby, the via hole VH can be formed with reference to the position of the cavity CV. Therefore, the positional accuracy of the via hole VH in the package 701 can be improved.

[0060] Also, when the via hole VH is formed, the position of the cavity CV is recognized in step ST411 (FIG. 11), and in step ST412 (FIG. 11), based on the position thus recognized, the position where laser processing is to be performed is determined. Thereby, the accuracy of the relative position between the cavity CV and the via hole VH can be increased. Further, since the configuration recognized for ensuring this relative position is the cavity CV which has a relatively large dimension, the recognition (typically image recognition) can be easily performed. Note that the accuracy of the relative position between the via hole VH and the substrate wiring portion 200 is usually sufficiently ensured by referring to the position of the cavity CV and the position of the substrate wiring portion 200 (or the corresponding position) in the lamination process of the substrate green body GS (FIG. 14) and the frame-shaped green sheet GF (FIG. 16). However, when the accuracy of the relative position between the via hole VH and the substrate wiring portion 200 is particularly required, in addition to the recognition of the position of the cavity CV (step ST411), after the position of the substrate wiring portion 200 (or the corresponding position) is also recognized, laser processing of the via hole VH may be performed based on both of these positions.

[0061] Also, laser processing to the state shown in FIG. 18 using laser light with the first processing rate ratio (FIG. 11: step ST421) and laser processing to the state shown in FIG. 19 using laser light with the second processing rate ratio (FIG. 11: step ST422) are performed. Thereby, using laser light with the first processing rate ratio, the formation of the non-through hole VHp (FIG. 18) which becomes a part of the via hole VH can be efficiently advanced. Then, thereafter, by using laser light with the second processing rate ratio, the formation of the via hole VH (FIG. 19) can be easily and accurately stopped on the substrate wiring portion 200 without penetrating the substrate wiring portion 200. Therefore, it is possible to achieve both sufficient manufacturing efficiency and sufficient manufacturing yield.

[0062] <Embodiment 2> In the second embodiment, as step ST411 (FIG. 11) leading to the configuration of FIG. 18, a non-through hole VHp of the frame-shaped green sheet GF is formed by irradiating the frame-shaped green sheet GF with pulsed laser light having a first pulse energy. In other words, a via hole VH (FIG. 19) of the frame-shaped green sheet GF is partially formed. Then, as step ST412 (FIG. 11) leading to the configuration of FIG. 19, the via hole VH of the frame-shaped green sheet GF is made to reach the substrate wiring portion 200 by irradiating the frame-shaped green sheet GF with pulsed laser light having a second pulse energy. The second pulse energy is lower than the first pulse energy. Specifically, the first pulse energy may be 1 mJ or more and 40 mJ or less, and the second pulse energy may be 10 μJ or more and 200 μJ or less. Note that, except for these features of the second embodiment, since they are substantially the same as those of the first embodiment described above, the description thereof will not be repeated.

[0063] According to this embodiment, laser processing to the state shown in FIG. 18 (FIG. 11: step ST421) using laser light with the first pulse energy and laser processing to the state shown in FIG. 19 (FIG. 11: step ST422) using laser light with the second pulse energy are performed. Thereby, after efficiently forming a sufficiently deep non-through hole VHp (FIG. 18) with a small number of pulses using laser light with the first pulse energy, by using laser light with the second pulse energy, the bottom surface SH (FIG. 19) of the via hole VH can be easily and accurately stopped on the substrate wiring portion 200 without penetrating the substrate wiring portion 200. Therefore, it is possible to achieve both sufficient manufacturing efficiency and sufficient manufacturing yield. In addition, by avoiding an excessive total number of pulses, it is possible to avoid an excessive roundness of the shape of the shoulder portion of the via hole VH.

[0064] <Embodiment 3> In Embodiment 3, as step ST411 (FIG. 11) leading to the configuration of FIG. 18, by irradiating laser light with a first wavelength, a non-through hole VHp of the frame-shaped green sheet GF is formed. In other words, a via hole VH (FIG. 19) of the frame-shaped green sheet GF is partially formed. Then, as step ST412 (FIG. 11) leading to the configuration of FIG. 19, by irradiating laser light with a second wavelength, the via hole VH of the frame-shaped green sheet GF is made to reach the substrate wiring portion 200. The second wavelength is shorter than the first wavelength. Specifically, the first wavelength may be 9.4 μm or more and 10.7 μm or less, and the second wavelength may be 343 nm or more and 1064 nm or less.

[0065] The laser light with the first wavelength may be CO 2 laser light, and the laser light with the second wavelength may be solid laser light. The wavelength of the solid laser light is shorter than the wavelength of the CO 2 laser light. Note that the solid laser light may be directly generated by a laser oscillator that generates the laser light with the second wavelength, or may be indirectly generated by wavelength-converting the laser light from a solid laser oscillator that generates a wavelength longer than the second wavelength.

[0066] Note that, except for these features of Embodiment 3, since they are substantially the same as those of Embodiment 1 described above, the description thereof will not be repeated. Also according to this embodiment, an effect similar to that of Embodiment 2 described above can be obtained. Further, according to this embodiment, the non-through hole VHp that will be expanded into the via hole VH can be efficiently formed by using CO 2 laser light. Then, by using solid laser light to expand the non-through hole VHp into the via hole VH, it becomes easier to accurately stop the formation of the via hole VH on the substrate wiring portion 200 without penetrating the substrate wiring portion 200. From the above, it is possible to achieve both sufficient manufacturing efficiency and sufficient manufacturing yield.

[0067] The above has described Embodiments 1 to 3 of the present invention and their modified examples. These embodiments and modified examples may be freely combined with each other as long as they do not contradict each other. For example, for the laser light for laser processing, the pulse energy may be adjusted as described in Embodiment 2, and the wavelength may be adjusted as described in Embodiment 3.

Explanation of Reference Numerals

[0068] 110: Ceramic substrate part 110i: Insulating film 120: Ceramic frame part 200: Substrate wiring part 211, 212: Element electrode pads 220: Relay electrode 301~304: Package electrode pads 401~403: Wiring layers 411~414: Substrate via electrodes 510: Via electrode 600: Metallized layer 701: Package 890: Quartz blank (electronic component) 960: Brazing material 980: Lid CV: Cavity G510: Electrode green body G600: Metallized green body GF: Frame-shaped green sheet GS: Substrate green body VH: Via hole

Claims

1. A method for manufacturing a package (701) provided with a cavity (CV) for accommodating an electronic component (890), the package (701) including a ceramic substrate portion (110), a substrate wiring portion (200) provided on the ceramic substrate portion (110), a ceramic frame portion (120) disposed on the ceramic substrate portion (110) where the substrate wiring portion (200) is provided and surrounding the cavity (CV), and a via electrode (510) provided on the ceramic frame portion (120) and reaching the substrate wiring portion (200), the manufacturing method comprising: forming the ceramic substrate portion (110) where the substrate wiring portion (200) is provided as a substrate green body (GS); forming the ceramic frame portion (120) as a frame-shaped green sheet (GF) having a frame shape surrounding the cavity (CV); laminating the frame-shaped green sheet (GF) on the substrate green body (GS); forming a via hole (VH) in the frame-shaped green sheet (GF) that reaches the substrate wiring portion (200) without penetrating the substrate wiring portion (200) by performing laser processing; forming the via electrode (510) as an electrode green body (G510) in the via hole (VH) of the frame-shaped green sheet (GF); firing the substrate green body (GS), the frame-shaped green sheet (GF), and the electrode green body (G510); A method for manufacturing a package (701), comprising the above steps.

2. The step of forming the via hole (VH) comprises: recognizing the position of the cavity (CV) of the frame-shaped green sheet (GF); determining a position where the laser processing is to be performed based on the position recognized by the step of recognizing the position of the cavity (CV) of the frame-shaped green sheet (GF). The method for manufacturing a package (701) according to Claim 1, comprising the above steps.

3. Defining a processing rate ratio of laser light as the ratio of the processing rate for the material of the substrate wiring portion (110) in the substrate green body (GS) to the processing rate for the material of the ceramic frame portion (120) in the frame-shaped green sheet (GF), The step of forming the via hole (VH) comprises: A step of partially forming the via holes (VH) of the frame-shaped green sheet (GF) by irradiating laser light with a first processing rate ratio; A step of causing the via holes (VH) of the frame-shaped green sheet (GF) to reach the substrate wiring portion (200) by irradiating laser light with a second processing rate ratio; The method for manufacturing a package (701) according to claim 1 or 2, including the above steps, wherein the second processing rate ratio is lower than the first processing rate ratio.

4. The step of forming the via holes (VH) includes: A step of partially forming the via holes (VH) of the frame-shaped green sheet (GF) by irradiating the frame-shaped green sheet (GF) with pulsed laser light having a first pulse energy; A step of causing the via holes (VH) of the frame-shaped green sheet (GF) to reach the substrate wiring portion (200) by irradiating the frame-shaped green sheet (GF) with pulsed laser light having a second pulse energy; The method for manufacturing a package (701) according to claim 1 or 2, including the above steps, wherein the second pulse energy is lower than the first pulse energy.

5. The method for manufacturing a package (701) according to claim 4, wherein the first pulse energy is 1 mJ or more and 40 mJ or less, and the second pulse energy is 10 μJ or more and 200 μJ or less.

6. The step of forming the via holes (VH) includes: A step of partially forming the via holes (VH) of the frame-shaped green sheet (GF) by irradiating laser light having a first wavelength; A step of causing the via holes (VH) of the frame-shaped green sheet (GF) to reach the substrate wiring portion (200) by irradiating laser light having a second wavelength; The method for manufacturing a package (701) according to claim 1 or 2, including the above steps, wherein the second wavelength is shorter than the first wavelength.

7. The method for manufacturing a package (701) according to claim 6, wherein the first wavelength is 9.4 μm or more and 10.7 μm or less, and the second wavelength is 343 nm or more and 1064 nm or less.

8. A method for manufacturing a package (701) provided with a cavity (CV) for housing an electronic component (890), the package (701) including a ceramic substrate portion (110), a substrate wiring portion (200) provided on the ceramic substrate portion (110), a ceramic frame portion (120) disposed on the ceramic substrate portion (110) where the substrate wiring portion (200) is provided and surrounding the cavity (CV), and a via electrode (510) provided on the ceramic frame portion (120) and reaching the substrate wiring portion (200), the manufacturing method comprising: forming the ceramic substrate portion (110) where the substrate wiring portion (200) is provided as a substrate green body (GS); forming the ceramic frame portion (120) as a frame-shaped green sheet (GF) having a frame shape surrounding the cavity (CV); laminating the frame-shaped green sheet (GF) on the substrate green body (GS); Irradiating the frame-shaped green sheet (GF) with CO ２ forming, by irradiating laser light, a recess (VHp) that will later become a via hole (VH) in the frame-shaped green sheet (GF); After the step of forming the concave portion (VHp) by irradiating the frame-shaped green sheet (GF) with CO ２ After the step of forming the concave portion (VHp) by irradiating the frame-shaped green sheet (GF) with laser light, by irradiating the concave portion (VHp) with solid laser light, a step of forming the via hole (VH) that reaches the substrate wiring portion (200) without penetrating the substrate wiring portion (200) in the frame-shaped green sheet (GF); forming the via electrode (510) as an electrode green body (G510) within a via hole (VH) of the frame-shaped green sheet (GF); firing the substrate green body (GS), the frame-shaped green sheet (GF), and the electrode green body (G510); A method for manufacturing a package (701), comprising the above steps.

9. The wavelength of the solid laser light is shorter than the wavelength of the CO ２ laser light, the method for manufacturing a package (701) according to claim 8.

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