CN114072912A

CN114072912A - Package body

Info

Publication number: CN114072912A
Application number: CN201980097998.2A
Authority: CN
Inventors: 间濑淳; 伊藤阳彦
Original assignee: NGK Insulators Ltd; NGK Electronics Devices Inc
Current assignee: NGK Insulators Ltd; NGK Electronics Devices Inc
Priority date: 2019-10-11
Filing date: 2019-10-11
Publication date: 2022-02-18
Also published as: WO2021070375A1; JP7008168B2; JPWO2021070375A1

Abstract

The package (800) has: a mounting Surface (SM) on which an electronic component (902) is mounted; a Chamber (CV) located on the setting Surface (SM); and a mounting face (SF) for mounting a cover body (907) for sealing the Cavity (CV). The package (800) comprises: a base (810) composed of ceramic and having a Chamber (CV); and a wiring portion (820) extending from the Cavity (CV) of the base portion (810) and penetrating the base portion (810). The base (810) includes a bottom (811) and a frame (812). The bottom portion (811) has a mounting Surface (SM) having a size that includes a rectangle having a long side of 10mm or more. The frame portion (812) is provided on the bottom portion (811) outside the mounting Surface (SM) so as to surround the Cavity (CV), and has a ceramic firing surface as a mounting Surface (SF).

Description

Package body

Technical Field

The present invention relates to a package, and more particularly to a package for electronic components.

Background

Japanese patent laid-open No. 2006-344838 (patent document 1) discloses a solid-state image pickup device. The solid-state image pickup device includes an image pickup element mounted in a concave ceramic package. As the size of the package, a 10mm square size is exemplified. The image pickup element is, for example, a Charge Coupled Device (CCD) type or a Complementary Metal Oxide Semiconductor (CMOS) type. Since the package has a size of 10mm square, the image pickup device mounted therein is much smaller than 10mm even in the long side. The opening of the package is sealed by a translucent window member. The window member mounting surface of the package is polished and planarized to improve the adhesion of the window member and the airtightness thereof, and to serve as a reference surface for mounting the image pickup device.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2006-344838

Disclosure of Invention

Problems to be solved by the invention

As an electronic component mounted on a package, there is also an electronic component having a size including a rectangle having a long side of 10mm or more. For example, a high-performance solid-state image pickup device for a large camera needs to have a larger image pickup portion than a solid-state image pickup device for a small camera, and more specifically, is often configured as a semiconductor chip having a size of about 10 to 50mm square. In response to this, a package for mounting the solid-state image pickup element requires a large mounting surface. As a result, the influence of warpage due to firing shrinkage difference of the ceramic package and the like becomes larger than the size, and thus the flatness and the parallelism of the frame portion (sealing surface), the rear surface portion (mounting surface to the substrate), and the bottom portion of the chamber (image pickup device mounting surface) are likely to be disturbed. Particularly, when the flatness of the mounting surface is low, the airtightness between the mounting surface of the package and the lid becomes low. In addition, when the electronic component is a solid-state image pickup element, it is necessary to consider the optical axis, and therefore there is a concern about the parallelism between the solid-state image pickup element and the lid. Therefore, conventionally, the flatness of the mounting surface is improved to, for example, about 30 to 50 μm by polishing.

However, according to the study by the inventors of the present invention, dust generation into the cavity of the package is likely to occur from the ground mounting surface. The dust may adversely affect the operation of the electronic component. In particular, when the electronic component is a solid-state image pickup element, dust may cause a pixel defect, and this problem is particularly serious in the case of a large-sized solid-state image pickup element which is required to have high performance in many cases. The present invention has been made to solve the above problems, and an object thereof is to provide a package capable of preventing malfunction of an electronic component due to dust.

Means for solving the problems

The package according to one embodiment of the present invention includes: a mounting surface for mounting an electronic component; a chamber located on the mounting face; and a mounting surface for mounting a cover for sealing the cavity. The package body includes: a base composed of ceramic and having a cavity; and a wiring portion extending from the cavity of the base portion and penetrating the base portion. The base includes a bottom portion and a frame portion. The bottom portion has a mounting surface having a size including a rectangle having a long side of 10mm or more. The frame portion is provided on the bottom portion outside the mounting surface so as to surround the cavity, and has a ceramic fired surface (as-fired surface) as a mounting surface.

Effects of the invention

According to the package of one embodiment of the present invention, the mounting surface to which the lid body is mounted is a ceramic fired surface. This suppresses dust from the mounting surface, as compared with the case where the mounting surface is a polished surface. Therefore, malfunction of the electronic component due to foreign matter in the chamber can be prevented.

The objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description and the accompanying drawings.

Drawings

Fig. 1 is a sectional view schematically showing a configuration of an electronic device according to an embodiment of the present invention.

Fig. 2 is a sectional view schematically showing the structure of the package of fig. 1.

Fig. 3 is an electron micrograph of a mounting surface of a package of a comparative example.

Fig. 4 is an electron micrograph of a mounting surface of the package according to the embodiment.

Fig. 5 is an image of an electron micrograph of a fracture surface of the package of the embodiment.

Fig. 6 is a diagram showing an image obtained by applying binarization processing to the image of fig. 5.

Fig. 7 is a diagram illustrating an example of a cutting method, which is a method for calculating an average particle diameter from an electron micrograph of a mounting surface of a package according to the embodiment.

Detailed Description

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

Fig. 1 and 2 are cross-sectional views schematically showing the structure of an electronic device 900 and the structure of a package 800 used for manufacturing the electronic device 900 in the present embodiment, respectively.

The package 800 (fig. 2) includes: a mount surface SM for mounting an electronic component 902 (fig. 1); a chamber CV located on the installation face SM; and a mounting face SF for mounting a cover 907 for sealing the chamber CV. The package 800 has a base 810 and a wiring portion 820.

The base 810 is composed of ceramic. The ceramic is substantially composed of an insulator so that the base 810 can function as an insulating member. The ceramic does not necessarily have to be entirely composed of an insulator as long as the function can be ensured, and for example, a small amount of non-insulator particles may be dispersed among insulator particles occupying a large proportion by volume.

The base 810 has a chamber CV. The base 810 includes a bottom 811 and a frame 812.

The bottom 811 has a mounting face SM. The setting face SM has the following setting faces SM: has a size including a rectangle having a long side of 10mm or more. For example, the mounting surface SM is a rectangle having a long side of 10mm or more. The setting face SM may also have the following setting faces SM: has a size including a square having a side of 10mm or more. In addition, a rectangle is geometrically one of squares.

The frame portion 812 is provided outside the installation surface SM on the bottom portion 811 so as to surround the chamber CV. The frame 812 has a ceramic fired surface as the mounting surface SF. Here, the term "as-fired" means a state in which surface processing is not performed while the sintered state is maintained. Therefore, the "as-fired surface" is a surface having an as-fired state. In other words, "fired surface" means the outer surface (of a ceramic product after sintering) of the ceramic product. Therefore, the surface to be polished is not a fired surface.

The ceramic as the material of the base 810 preferably has an average particle diameter of 1 μm or more and 3 μm or less, more preferably 1.5 μm or less, on the mounting surface SF. The average particle diameter can be calculated from an electron microscope image of the mounting surface SF by using a cutting method. Specifically, a line segment of a known length completely crossing 10 to 50 crystal grains is drawn on a microscope image or photograph, and the known length is divided by the number of the crystal grains to calculate the average particle diameter.

The base 810 has a side surface SS extending from an outer edge of the mounting surface SF. The side SS may have a non-fracture surface SSa and a fracture surface SSb. In a general method for manufacturing a ceramic package product, a green laminate in which a plurality of products are arranged is subjected to a half-cut (groove processing) process using a knife. After firing, each product is singulated by a breaking step using the portion subjected to the groove processing. In this case, the non-fractured surface SSa is a fired surface (as-fired surface) obtained by firing after groove processing, and has substantially 0% porosity. The fracture surface SSb is a surface fractured by fracture after firing, and preferably has a porosity of 3% or less. In other words, the side SS has the non-fracture surface SSa having substantially no pores and the fracture surface SSb having pores, and the porosity of the latter is preferably 3% or less, more preferably 1.5% or less. The porosity can be calculated by binarizing an image of an electron micrograph of a surface to be evaluated. As shown in fig. 2, the fracture surface SSb may be located on a side surface of the bottom portion 811, or may be located on a side surface of the frame portion 812 or on a side surface extending across the bottom portion 811 and the frame portion 812 as a modification.

The ceramic preferably contains Al₂O₃、SiO₂And MnO as an essential component, containing molybdenum (Mo) atoms and Cr₂O₃As an arbitrary component. Al (Al)₂O₃The content of (b) is 82.0 mass% or more and 95.0 mass% or less. SiO 2₂The content of (b) is 3.0 to 8.0 mass%. The content of MnO is 2.0 to 6.0 mass%. With MoO₃Content of Mo atom converted to Cr atom₂O₃The total content of (b) is 4.0 mass% or less. At least a part of the Mo atoms may be contained as Mo oxide. At least a part of the Mo atoms may be contained as metal Mo. The content of the balance other than the above components in the composition of the ceramic is less than 0.1 mass%, and more preferably less than 0.05 mass%.

The wiring portion 820 extends from the chamber CV and penetrates the base portion 810. Specifically, the wiring portion 820 includes: an external electrode terminal 821 provided outside the cavity CV; an internal wiring 822 penetrating the base 810; and an internal electrode terminal 823 facing the chamber CV. The internal wiring 822 may be formed of at least any one of an internal electrode layer and a via wiring. The material of the wiring portion 820 is substantially made of a conductor so that the wiring portion 820 can function as a wiring member. The material does not have to be entirely composed of a conductor as long as the function can be ensured, and for example, a small amount of non-insulator regions may be dispersed in a conductor region occupying a large proportion by volume.

The electronic component 902 (fig. 1) is bonded to the internal electrode terminal 823 via the bonding layer 901. Thereby, the electronic component 902 is mounted on the mount surface SM via the bonding layer 901 and the internal electrode terminals 823. Electronic component 902 may have a size including a rectangle having a long side of 10mm or more, for example, a size including a square having a side of 10mm or more. The electronic component 902 may be a solid-state image pickup element. The solid-state image pickup element is, for example, a CMOS image sensor. In general, a CMOS image sensor is particularly excellent as a solid-state image sensor having a large image pickup portion required for a single-lens reflex camera, a partial monitoring camera, an industrial camera, and the like. The planar shape of the solid-state image pickup element may be a rectangle having a long side of 10mm or more, or may be a substantially square having a side of 10mm or more.

The cover 907 is attached to the attachment surface SF of the frame 812 via the adhesive layer 906. Thereby, the chamber CV of the package 800 is sealed. The adhesive layer 906 is made of, for example, a resin adhesive. The adhesive layer 906 may be in direct contact with the mounting surface SF and the cover 907, respectively. When the electronic component 902 is a solid-state image pickup element, at least a part of the cover 907 is substantially transparent to light to be picked up, and typically, the entire cover 907 is substantially transparent to light to be picked up.

In the present embodiment, the wiring portion 820 penetrates the bottom portion 811, but as a modification, a wiring portion penetrating between the bottom portion 811 and the frame portion 812 or a wiring portion penetrating the frame portion 812 may be provided. As a modification, a wiring portion connected to the electronic component 902 by a bonding wire may be provided.

According to package 800 (fig. 2) of the present embodiment, mounting surface SF to which lid 907 (fig. 1) is mounted is a ceramic fired surface. This suppresses dust from the mounting surface, as compared with the case where the mounting surface is a polished surface. Therefore, malfunction of the electronic component 902 due to foreign matter in the chamber CV can be prevented.

Fig. 3 is an electron micrograph of a polished surface of a mounting surface of a package according to a comparative example, and fig. 4 is an electron micrograph of a fired surface of a mounting surface SF of a package according to an example. In the comparative examples, the surface state was more uneven than in the examples, and degranulation was likely to occur. In the comparative example, the pores inside were made surface as defects (holes) by polishing, and foreign matter (ceramics, abrasive grains, or the like) generated during the polishing and various foreign matter in the process were likely to enter the defects. Therefore, dust may be detached from the foreign matter. Further, since the polishing process is a mechanical process, ceramic particles having a low sintering bonding force to the surrounding ceramic particles and ceramic particles adhering only to the surrounding ceramic particles are likely to be generated. Therefore, degranulation of the ceramic particles may easily occur.

The ceramic of the base 810 preferably has a porosity of 3% or less, particularly 1% or less, at the fracture surface SSb, and an average particle diameter of 1 μm or more and 3 μm or less, particularly 1.5 μm or less, at the mounting surface SF. Since the fracture surface SSb is not a fired surface (as-fired surface) unlike the non-fracture surface SSa and the mounting surface SF, it is generally difficult to set the porosity to 0%. However, the porosity can be suppressed to 3% or less, particularly 1% or less, and thereby foreign matter is suppressed from entering the pores in the cleaning step of production or the like. Thus, the possibility of dusting from the air holes is reduced. Further, since the average particle diameter on the mounting surface SF is 1 μm or more and 3 μm or less, particularly 1.5 μm or less, compactness can be secured. This improves the sintering bonding force, and thus suppresses the degranulation of the ceramic particles from the mounting surface SF. Thus, the possibility of dusting caused by threshing is reduced. This can more reliably suppress dust from the entire base 810.

Fig. 5 is an image of an electron micrograph of the ceramic surface at the fracture surface SSb of the package of the example, and fig. 6 is a view showing an image obtained by performing binarization processing for calculating the average particle diameter on the image of fig. 5. As shown in fig. 5, the pores are observed as a significantly denser area than its surroundings. Therefore, as shown in fig. 6, it is easy to perform binarization processing with a density threshold value at which only the above-described relatively dense region is basically extracted. In this example, the porosity was 0.98% by calculating the ratio of the region thus extracted.

Fig. 7 is a diagram illustrating an example of a cutting method, which is a method for calculating the average particle diameter based on an electron micrograph of the mounting surface SF of the package according to the embodiment. In this example, the length of the line segment is divided by the number of grains that each line segment traverses. The values thus obtained are then averaged over 3 line segments. Thus, the average particle diameter was 1.22. mu.m.

The electronic component 902 may be a solid-state image pickup element having a size including a rectangle having a long side of 10mm or more. This can sufficiently secure the size of the image pickup section of the solid-state image pickup element.

The ceramic of the base 810 preferably contains Al₂O₃、SiO₂And MnO as an essential component, containing Mo atoms and Cr₂O₃As an arbitrary component. Al (Al)₂O₃The content of (b) is 82.0 mass% or more and 95.0 mass% or less. SiO 2₂The content of (b) is 3.0 to 8.0 mass%. The content of MnO is 2.0 to 6.0 mass%. With MoO₃Content of Mo atom converted to Cr atom₂O₃The total content of (b) is 4.0 mass% or less. The content of the balance is less than 0.1 mass%, more preferably less than 0.05 mass%. By making the ceramic have such a composition, the dimensional accuracy of the base 810 made of ceramic is easily obtained. Therefore, the flatness of the mounting surface SF can be easily ensured without polishing. In addition, the parallelism of the mounting surface SF is easily ensured.

Specifically, since the content of the remaining amount is suppressed to less than 0.1 mass%, the respective components are uniformly sintered in a state of being dispersed without being segregated. Thereby, dimensional variations of the base 810 are suppressed. Therefore, the flatness of the mounting surface SF can be easily ensured without polishing. In addition, the parallelism of the mounting surface SF is easily ensured.

Further, as described above, the respective components are uniformly sintered in a state of being dispersed without being segregated, and thus the timings of melting the glass components of the base portion 810 are substantially the same on the side facing the firing setter and on the opposite side. This suppresses the base 810 from warping in the thickness direction due to the timing deviation. Therefore, it is easy to ensure the flatness and parallelism of the mounting surface SF without polishing.

The content of the balance is more preferably less than 0.05 mass%. This can further suppress dimensional variations. The content of the balance is particularly preferably 0 mass%. This can further suppress dimensional variations.

The ceramic of the base 810 includes a crystalline phase and a glassy phase. In the case where the ceramic contains Mo atoms as a colorant, the crystal phase is other than Al as the main crystal phase₂O₃The crystal phase contains a Mo crystal phase as a secondary crystal phase in addition to the crystal phase. The crystal phase may also contain Al₂O₃A crystal phase other than the Mo crystal phase (hereinafter referred to as "remaining crystal phase"). Here, when the X-ray diffraction pattern of the sample obtained by pulverizing the base 810 is measured, the main peak intensity of the remaining crystal phase with respect to Al is₂O₃The main peak intensity of the crystal phase is preferably 0.5% or less. This can suppress the occurrence of distortion in the glass phase due to the presence of the remaining crystal phase. This can improve the bending strength (so-called bending strength) of the ceramic.

Table 1 below shows the results of experiments for investigating the composition of the ceramics represented by composition numbers 1 to 25, the firing temperature suitable for the composition, and the relationship between the properties of the ceramic plate obtained from the composition.

[ TABLE 1 ]

To produce a ceramic plate, first, each raw material powder was mixed at the ratio shown in table 1 to obtain a mixed powder. In the obtained mixed powder, polyvinyl butyral, a tertiary amine, and a phthalic acid ester (diisononyl phthalate: DINP) were mixed as organic components, and IPA (isopropyl alcohol) and toluene were further mixed as solvents, thereby preparing a slurry. A green sheet having a thickness of 50 to 400 μm was produced by a doctor blade method using the prepared slurry. The obtained ceramic green sheet was cut into 50mm in length by 50mm in width, arranged on a Mo firing setter, and fired at the firing temperature (highest temperature) shown in Table 1 for 2 hours. Thus, 100 ceramic plates of each composition number were produced.

The dimensional deviation of the obtained ceramic plate was measured. Specifically, the outer dimensions of the ceramic plate are measured using a dimension measuring device. The mean and standard deviation thereof were calculated. The value obtained by dividing the standard deviation by the average value was taken as the dimensional deviation. As a result, the dimensional deviations of the composition numbers 1 to 17 in the composition numbers 1 to 25 are small, and particularly the dimensional deviations of the composition numbers 1 to 8 and 12 to 17 are smaller.

The number of ceramic plates having a defect on the surface thereof due to the attachment to the fired setter in the firing step was counted. As a result, the number of composition numbers 1 to 17 in composition numbers 1 to 25 is small, and particularly the number of composition numbers 1 to 5 and 12 to 17 is small.

The average value of the warpage amount of the ceramic plate was measured using a three-dimensional shape measuring instrument. As a result, the compositions No. 1 to No. 17 in the compositions No. 1 to No. 25 were small in warpage, particularly the compositions No. 1 to No. 9 and No. 12 to No. 17 were small in warpage.

The flexural strength of the ceramic plate was measured at room temperature in accordance with the 3-point flexural strength test based on JIS R1601. The relative dielectric constant of the ceramic plate was measured at a frequency of 10GHz at room temperature according to the cavity resonance method based on JIS R1641.

The composition numbers 1 to 17 suppress dimensional deviation, sticking to a setter plate and warping as compared with the composition numbers 18 to 25. This is considered to be due to the fact that Al is added₂O₃、SiO₂MnO and a colorant (Mo atom or/and Cr)₂O₃) The content of the remainder other than the above is suppressed to less than 0.1 mass%, and therefore, the respective components are uniformly sintered in a state of being dispersed without segregation. In addition, MgO and ZrO are added₂The same results were obtained with additives other than CaO and BaO, and this was confirmed experimentally.

Further, warpage is further suppressed in composition Nos. 1 to 9 and 12 to 17, in which the content of the remainder is 0.07 mass% or less. Further, dimensional variations are further suppressed in composition Nos. 1 to 8 and 12 to 17 in which the content of the remaining amount is less than 0.05 mass%. In addition, in the composition numbers 1-5 and 12-17 with the balance content of 0 mass%, not only the dimensional deviation is further inhibited, but also the sticking to the setter plate is further inhibited.

In addition, SiO is added₂The composition No. 1 to 15, wherein the ratio of the content of (B) to the content of MnO is 0.8 to 2.1, has a flexural strength of 700MPa or more. Therefore, it can be seen that the composition numbers 1 to 15 are suitable for the case where strength is requiredA ceramic package (for example, a package for sealing a vibrator or a semiconductor element).

In addition, SiO is added₂The composition No. 15 to 17, in which the ratio of the content of (B) to the content of MnO is 1.9 to 3.5, can realize a relative dielectric constant of 8.0 to 9.0 and a bending strength of 390MPa or more at the same time. Therefore, the composition numbers 15 to 17 are suitable for ceramic packages (for example, packages for sealing optical semiconductor elements) requiring a relatively low relative dielectric constant.

Although the present invention has been described in detail, the above description is illustrative in all aspects, and the present invention is not limited thereto. It should be understood that numerous variations not illustrated may be assumed without departing from the scope of the invention.

Description of the symbols

800 Package

810 base

811 bottom part

812 frame portion

820 wiring part

821 external electrode terminal

822 internal wiring

823 internal electrode terminal

900 electronic device

901 bonding layer

902 electronic component

906 adhesive layer

907 cover body

CV chamber

SF mounting surface

SM installation surface.

Claims

1. A package body has: a mounting surface for mounting an electronic component; a chamber located on the mounting face; and a mounting surface for mounting a cover for sealing the chamber, wherein,

the package is provided with:

a base composed of ceramic and having the cavity; and

a wiring portion extending from the cavity of the base portion and penetrating the base portion,

the base includes: a bottom portion having the mounting surface having a size including a rectangle having a long side of 10mm or more; and a frame portion provided on the bottom portion outside the mounting surface so as to surround the cavity, and having a fired surface of the ceramic as the mounting surface.

2. The package of claim 1,

the base having a side extending from an outer edge of the mounting surface, the side including a fracture surface,

the ceramic has an average particle diameter of 1 to 3 [ mu ] m on the mounting surface and a porosity of 3% or less on the fracture surface.

3. The package of claim 1 or 2,

the electronic component is a solid-state image pickup element having a size including a rectangle having a long side of 10mm or more.

4. The package of any one of claims 1 to 3,

the ceramic contains Al₂O₃、SiO₂And MnO as an essential component, containing molybdenum atoms and Cr₂O₃As an arbitrary component (a) of (b),

Al₂O₃the content of (B) is 82.0 to 95.0 mass%,

SiO₂the content of (B) is 3.0 to 8.0 mass%,

the MnO content is 2.0 to 6.0 mass%,

with MoO₃Converted molybdenum atom content and Cr₂O₃The total content of (B) is 4.0 mass% or less,

the balance being less than 0.1 mass%.

5. The package of any one of claims 1 to 3,

Al₂O₃the content of (B) is 82.0 to 95.0 mass%,

SiO₂the content of (B) is 3.0 to 8.0 mass%,

the MnO content is 2.0 to 6.0 mass%,

the balance being less than 0.05 mass%.