WO2018235925A1

WO2018235925A1 - Window material, and optical package

Info

Publication number: WO2018235925A1
Application number: PCT/JP2018/023703
Authority: WO
Inventors: 淳平滝川; 圭輔花島; 菊川　信也; 渋谷　幸一; 平本　誠; 朋美安部; 優梨子城戸
Original assignee: Ａｇｃ株式会社
Priority date: 2017-06-22
Filing date: 2018-06-21
Publication date: 2018-12-27
Also published as: JPWO2018235925A1; KR102563840B1; JP7205470B2; TWI784013B; TW201906198A; KR20200021462A

Abstract

A window material for an optical package provided with an optical element is provided which is equipped with: a substrate comprising an inorganic material; and a bonding layer provided on one surface of the substrate comprising the inorganic material. The volume ratio of gold in the bonding layer is 10% or lower.

Description

Window material, optical package

The present invention relates to a window material and an optical package.

Conventionally, after an optical element such as a light emitting diode is disposed in a recess of a circuit board, the opening of the recess may be sealed with a window material provided with a transparent resin substrate or the like to be used as an optical package.

In this case, the window material is bonded to the circuit board by a resin adhesive or the like, but improvement of the hermetic sealing property is required depending on the type of the optical element and the like. For this reason, using a metal material instead of the circuit board and the window material instead of the resin adhesive has been studied.

For example, in Patent Document 1, a mounting substrate, an ultraviolet light emitting element mounted on the mounting substrate, a spacer provided on the mounting substrate and having a through hole for exposing the ultraviolet light emitting element, and the spacer A cover disposed on the spacer so as to close the through hole; and the spacer is the spacer main body formed of Si, and the spacer main body of the spacer on the side facing the mounting substrate of the spacer main body (I) A second bonding metal layer facing the bonding metal layer and formed along the entire periphery of the outer peripheral edge of the facing surface, and the through hole is formed in the spacer main body The opening area of the through hole gradually increases with distance from the mounting substrate, and the cover is formed of glass that transmits ultraviolet light emitted from the ultraviolet light emitting element. And the spacer and the cover are directly bonded, and the second bonding metal layer of the spacer and the first bonding metal layer of the mounting substrate extend over the entire circumference of the second bonding metal layer. And a light emitting device characterized in that they are joined by AuSn.

Japanese Patent No. 5877487

However, since the cover used in the light emitting device disclosed in Patent Document 1 is bonded to the mounting substrate by AuSn through the spacer, and the amount of use of gold (Au) is large, there is a problem from the viewpoint of cost. .

SUMMARY OF THE INVENTION In view of the problems of the prior art, one aspect of the present invention is to provide a window material with reduced cost.

In one aspect of the present invention for solving the above problems, it is a window material for an optical package provided with an optical element,
A substrate of inorganic material,
And a bonding layer disposed on one side of the substrate of the inorganic material,
The window material is provided wherein the volume fraction of gold in the bonding layer is 10% or less.

According to one aspect of the present invention, it is possible to provide a window material with reduced cost.

Structure explanatory drawing of the window material of this embodiment. Explanatory drawing of the structural example of the side of the base | substrate of an inorganic material. Explanatory drawing of the position of the thickness measurement point of the solder layer of window material. Configuration explanatory drawing of the optical package of this embodiment. Explanatory drawing of the material before cutting | disconnection of the base | substrate of the inorganic material before the singulation in an Example. Explanatory drawing of the temperature profile of the reflow test in Example 1. FIG. 7 is a temperature profile of a bonding step in Example 2. Explanatory drawing of the linear pattern produced in the side of the base | substrate of the inorganic material after singulation in Example 4. FIG.

Hereinafter, although the form for carrying out the present invention is explained with reference to drawings, the present invention is not limited to the following embodiment, and does not deviate from the scope of the present invention. Various modifications and substitutions may be made.
[Window material]
One structural example of the window material of this embodiment will be described.

The window material of the present embodiment relates to a window material for an optical package provided with an optical element, comprising a substrate of an inorganic material and a bonding layer disposed on one surface of the substrate of the inorganic material, in the bonding layer The volume fraction of gold is less than 10%.

The structural example of the window material of this embodiment is concretely demonstrated below, using FIG. 1 (A) and FIG. 1 (B). FIG. 1A schematically shows a cross-sectional view in a plane parallel to the laminating direction of the base material 11 of the inorganic material of the window member 10 of the present embodiment and the bonding layer 12. Moreover, FIG. 1 (B) has shown the structure at the time of seeing the window material 10 shown to FIG. 1 (A) along the block arrow A shown in FIG. 1 (A). That is, the bottom view of the window material 10 shown to FIG. 1 (A) is shown.

The window material 10 of the present embodiment has a base 11 of an inorganic material and a bonding layer 12. The bonding layer 12 can be disposed on one surface 11 a of the inorganic material base 11.

Here, one surface 11 a of the inorganic material base 11 corresponds to the surface to be bonded to the circuit substrate provided with the optical element when the optical package is manufactured. That is, it can be said that the one surface 11 a of the inorganic material base 11 is the surface facing the optical element.

The other surface 11b opposite to the surface 11a of the inorganic material base 11 is the surface exposed to the outside when the optical package is used.

In addition, although the case where the base | substrate 11 of an inorganic material is a plate-like shape is shown as an example in FIG. 1, it is not limited to the shape which concerns.

Here, each member contained in the window material of this embodiment is demonstrated.
(Base of inorganic material)
The substrate 11 of the inorganic material is not particularly limited, and any material may be used to be in any shape.

However, when the base 11 of the inorganic material is an optical package, among the light related to the optical element included in the circuit substrate, light in a wavelength range that is particularly required to be transmitted (hereinafter, “light in a desired wavelength range” For the material to be described, it is preferable to select the material, the thickness thereof, and the like so that the transmittance is sufficiently high. For example, for light in a desired wavelength range, the transmittance is preferably 50% or more, more preferably 70% or more, still more preferably 80% or more, and particularly preferably 90% or more.

When light of a desired wavelength region is light in the infrared region, the substrate 11 of the inorganic material preferably has a transmittance of 50% or more and 70% or more for light having a wavelength of 0.7 μm or more and 1 mm or less, for example More preferably, 80% or more is more preferable, and 90% or more is particularly preferable.

In the case where light of a desired wavelength range is light in the visible range (blue to green to red), the substrate 11 of inorganic material has a transmittance of 50% or more for light in a wavelength range of 380 nm to 800 nm, for example Preferably, it is 70% or more, more preferably 80% or more, and particularly preferably 90% or more.

The inorganic material base 11 preferably has a transmittance of 50% or more, more preferably 70% or more, for light with a wavelength of 200 nm or more and 380 nm or less, for example, when light in a desired wavelength range is light in the ultraviolet range. 80% or more is more preferable, and 90% or more is particularly preferable.

When the light of a desired wavelength region is UV-A light in the ultraviolet region, the substrate 11 of the inorganic material preferably has a transmittance of 50% or more and 70% or more for light having a wavelength of 315 nm or more and 380 nm or less, for example Is more preferably 80% or more, and particularly preferably 90% or more.

When the light of a desired wavelength region is UV-B light in the ultraviolet region, the substrate 11 of inorganic material preferably has a transmittance of 50% or more, 70% or more, for light with a wavelength of 280 nm to 315 nm, for example. Is more preferably 80% or more, and particularly preferably 90% or more.

When the light of a desired wavelength region is UV-C light in the ultraviolet region, the substrate 11 of the inorganic material preferably has a transmittance of 50% or more and 70% or more for light having a wavelength of 200 nm or more and 280 nm or less. Is more preferably 80% or more, and particularly preferably 90% or more.

The transmittance of the inorganic material base 11 can be measured according to JIS K 7361-1 (1997).

The material of the base 11 of the inorganic material can be arbitrarily selected as described above, and is not particularly limited. However, from the viewpoint of particularly enhancing the hermetic sealing property and the durability, for example, quartz, Glass etc. can be used preferably. The quartz includes quartz glass and one containing 90% by mass or more of SiO ₂ . Examples of the glass include soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, crystallized glass, and high refractive index glass (nd ≧ 1.5). The material of the inorganic material base is not limited to one type, and two or more types of materials may be used in combination. Therefore, for example, as a material of the base 11 of the inorganic material, it is selected from, for example, quartz, soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, crystallized glass and high refractive index glass (nd nd 1.5) One or more of the materials listed above can be preferably used.

When glass is used as the material of the substrate 11 of the inorganic material, the substrate 11 of the inorganic material may be subjected to a chemical strengthening treatment.

The thickness of the inorganic material base 11 is not particularly limited either, but is preferably, for example, 0.03 mm or more, more preferably 0.05 mm or more, and still more preferably 0.1 mm or more. And 0.3 mm or more are particularly preferable.

By making the thickness of the substrate 11 of inorganic material 0.03 mm or more, while sufficiently exerting the strength required for the optical package, moisture etc. can be obtained through the surface of the substrate 11 of the inorganic material of the window material. It is possible to particularly suppress the penetration to the side where it is disposed. The strength of the optical package can be particularly enhanced by setting the thickness of the inorganic material base 11 to 0.3 mm or more as described above, which is preferable.

The upper limit of the thickness of the inorganic material base 11 is also not particularly limited, but is preferably 5 mm or less, more preferably 3 mm or less, and still more preferably 1 mm or less. This is because the transmittance of light in a desired wavelength range can be sufficiently increased by setting the thickness of the inorganic material base 11 to 5 mm or less. It is further preferable to set the thickness of the substrate 11 made of an inorganic material to 1 mm or less, in particular because the height of the optical package can be reduced.

The shape of the inorganic material base 11 is not particularly limited, and the thickness does not have to be uniform. For this reason, when the thickness of the inorganic material base is not uniform, it is preferable that the thickness of the portion of the inorganic material base located on the optical path of the light related to the optical element at least in the optical package is in the above range. It is more preferable that the thickness of the substrate of the inorganic material be in the above-mentioned range in any part.

The shape of the inorganic material base 11 is not particularly limited as described above. For example, a plate-like shape or a shape in which a lens is integrated, that is, a shape including a concave portion and a convex portion derived from the lens can be used. Specifically, for example, one surface 11a of the inorganic material base 11 is a flat surface, and the other surface 11b has a protrusion or a recess, or the shape of one surface 11a and the shape of the other surface 11b. The form which became reverse to the form which concerns is mentioned. In addition, one surface 11a of the inorganic material base 11 has a convex portion, and the other surface 11b has a recess, or the shape of one surface 11a and the shape of the other surface 11b are opposite to the related embodiment. Form. Furthermore, the form in which each of the one surface 11a of the base | substrate 11 of the inorganic material and the other surface 11b have a convex part or a recessed part is mentioned.

Even when one surface 11a of the inorganic material base 11 has a protrusion or a recess, the portion on which the bonding layer 12 of the surface 11a of the inorganic material base 11 is disposed is, for example, a plurality of window materials When manufacturing No. 10, in order to suppress the dispersion | variation in the shape of the joining layer 12 between the window materials 10, it is preferable that it is flat.

The side surface of the inorganic material base 11 can have a linear pattern along the outer periphery of one surface 11a.

The window material of the present embodiment can be disposed, for example, on a circuit board on which an optical element is disposed, to form an optical package. Therefore, depending on the form of the optical package, the size of the window material may be very small. Therefore, it is preferable to adopt a cutting method using a laser beam when cutting the material of the inorganic material base 11 before cutting into a desired size.

In the cutting method using the laser light, for example, first, the focal position of the laser light is set to an arbitrary position in the thickness direction of the material before cutting the substrate of the inorganic material, and the irradiation position of the laser light is a cutting line. The material before the cutting of the irradiation position of the laser beam and / or the substrate of the inorganic material is moved along the line. Thereafter, by applying a force so that the cutting line becomes a fulcrum, or by applying a natural force, the pre-cutting material of the inorganic material substrate can be cut into any shape along the cutting line.

In the above-mentioned cutting method, the focal position of the laser light is set to an arbitrary position in the thickness direction of the material before cutting the substrate of the inorganic material, and the irradiation position of the laser light is moved to cut the substrate of the inorganic material before cutting. It is considered that there is a change in the binding state of the inorganic material at the place where the focal position of the laser light of the material passes. For this reason, it is presumed that the material before cutting of the substrate of the inorganic material can be easily cut starting from the portion where the bonding state of the inorganic material is changed by applying a force thereafter.

Depending on the thickness of the inorganic material substrate before cutting, the focal position of the laser beam in the thickness direction of the inorganic material substrate before cutting is changed, and the laser beam is irradiated multiple times along the cutting line. You can also. Thus, when the focal position of the laser light is changed and the laser light is irradiated a plurality of times along the cutting line, the laser in the thickness direction of the material before cutting the substrate of the inorganic material each time the laser light is irradiated. It is preferable to change the focal position of the laser light from a position far from the light incident surface to a near position.

The number of times of laser beam irradiation is preferably 2 or more, more preferably 3 or more, and still more preferably 5 or more, since generation of defects such as chipping, cracking and chipping of the cut surface can be suppressed. The upper limit of the number of times of laser light irradiation is not particularly limited, but if it exceeds 10 times, the cost is increased and the number is preferably 10 times or less.

And when it cut | disconnects by the cutting method which concerns, the linear pattern considered to be produced by the binding state of inorganic material changing remains in the position where the focus position of the laser beam passed. Since the focal position of the laser beam is set to an arbitrary position in the thickness direction of the material before cutting the substrate of the inorganic material, for example, as shown in FIG. 2, one side of the substrate 11 of the inorganic material It can be set as the linear pattern 111 along the outer periphery of 11a and the other surface 11b. From the viewpoint of suppressing the generation of defects such as chips, cracks and chipping at the time of cutting, this linear pattern 111 is a linear pattern parallel to one surface 11 a or the other surface 11 b of the inorganic material base 11. It is preferable to have one, but it does not have to be parallel.

And as above-mentioned, when irradiating a laser beam multiple times along a cutting line, the linear pattern as many as the frequency | count of irradiation remains in the side of the base | substrate of the obtained inorganic material, ie, a cut surface. Moreover, it is preferable that the space | intervals of the linear patterns which can be made are substantially the same from the point of suppressing generation | occurrence | production of defects, such as a notch of a cut surface. Specifically, for example, it is preferable that the width between the linear patterns included in the side surface of the substrate of the inorganic material obtained after cutting is within an error within 20% of the median. Since the linear patterns occur at positions corresponding to the focal position of the laser light, the distance between the linear patterns can be controlled by the focal position of the laser light.

In addition, the cutting method of the base | substrate 11 of an inorganic material is not limited to the above-mentioned example, It can cut | disconnect by arbitrary methods. When cutting is performed by a method other than the above-described cutting method, the side surface of the substrate 11 of the inorganic material, that is, the cut surface may have a cross-sectional shape different from that described above. Other cutting methods include, for example, dicing saws and wire saws. These cutting methods are effective when the thickness of the material before cutting the substrate of the inorganic material is 1 mm or more.

An antireflective film can also be disposed on the surface of the substrate 11 made of an inorganic material. By arranging an anti-reflection film, in the case of an optical package, it is suppressed that light from the optical element or the light from the outside is reflected on the surface of the base 11 of the inorganic material, and light from the optical element or the light from the outside is Permeability can be increased and is preferred. The antireflective film is not particularly limited, but, for example, a multilayer film can be used, and the multilayer film is made of alumina (aluminum oxide, Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), titanium oxide (TiO ₂₎ And the like. The first layer which is a layer of one or more kinds of materials selected from etc.) and the second layer which is a layer of silica (silicon oxide, SiO ₂ ) can be alternately laminated. Although the number of layers constituting the multilayer film is not particularly limited, for example, the first layer and the second layer constitute one set, and the multilayer film includes the first layer and the second layer in one. It is preferable to have more than one set, and more preferable to have two or more sets. This is because when the multilayer film includes at least one set of the first layer and the second layer, it is possible to particularly suppress that light is reflected on the surface of the base 11 of the inorganic material.

The upper limit of the number of layers constituting the multilayer film is also not particularly limited, but it is preferable to have four or less sets of the first layer and the second layer from the viewpoint of, for example, productivity.

When the antireflective film is provided, the antireflective film is preferably disposed on at least one surface 11a of the inorganic material base 11, and more preferably disposed on both surfaces of the one surface 11a and the other surface 11b. In the case where antireflective films are disposed on both sides of one surface 11a and the other surface 11b, the configuration of both antireflective films may be different, but from the viewpoint of productivity etc., the antireflective films have the same configuration. Is preferred.

When the above-described multilayer film is used as the antireflective film, it is preferable that the second layer of silica be located on the outermost surface. When the second layer of silica is located on the outermost surface of the antireflective film, the surface of the antireflective film has a composition similar to that of the surface of the glass substrate, and the durability and the adhesion to the bonding layer 12 are particularly high. Because it is preferable.
(Bonding layer)
The bonding layer 12 corresponds to a member for bonding the substrate 11 made of an inorganic material and a circuit board provided with an optical element when the package is an optical package. Therefore, the bonding layer 12 may be a member capable of bonding the base 11 of the inorganic material and the circuit substrate provided with the optical element, and the specific configuration thereof is not particularly limited. However, it is preferable that the bonding layer 12 be made of a metal material from the viewpoint of enhancing the airtightness in forming an optical package. Moreover, it is preferable that the volume ratio of the gold in the joining layer 12 of the joining layer 12 is 10% or less. By setting the volume ratio of gold in the bonding layer 12 to 10% or less, the ratio of gold contained in the bonding layer can be sufficiently suppressed, and the cost of the window material can be suppressed. The volume ratio of gold in the bonding layer 12 is more preferably 8% or less, and still more preferably 6% or less.

Since the bonding layer 12 can also contain no gold, the volume ratio of gold in the bonding layer 12 can be set to 0 or more.

The bonding layer 12 can make each layer, such as a solder layer, which will be described later contained, have a substantially uniform thickness. Therefore, for example, when a layer containing gold in the bonding layer 12 is present as a gold layer made of gold, the volume ratio of gold is the ratio of the thickness of the gold layer to the thickness of the bonding layer 12 It can also be done. When the gold-containing layer also contains a component other than gold, the gold content in the gold-containing layer is in proportion to the thickness of the gold-containing layer in the thickness of the bonding layer 12 It can also be a value obtained by multiplying

When the volume ratio of gold in the bonding layer is calculated using the thickness of each layer as described above, the average value of the simple average can be used as the thickness of the solder layer described later.

The bonding layer 12 preferably includes a base metal layer 121 and a solder layer 122, as shown in FIG. 1A, for example.

The base metal layer 121 can have a function of enhancing the adhesion between the inorganic material base 11 and the solder layer 122. The structure of the base metal layer 121 is not particularly limited, but is preferably composed of a plurality of layers as shown in FIG. 1 (A).

The structure of the base metal layer 121 is not particularly limited, but can be composed of, for example, two layers or three layers. Specifically, for example, the first base metal layer 121A and the second base metal layer 121B can be provided in order from the side of the base 11 of the inorganic material. In addition, a third base metal layer (not shown) can also be disposed between the second base metal layer 121 B and the solder layer 122.

The first base metal layer 121A can have a function of enhancing the adhesion between the inorganic material base 11 and another layer. The material of the first underlying metal layer 121A is preferably a material capable of enhancing the adhesion between the inorganic material base 11 and the other layer, and more preferably a material capable of enhancing the airtightness. The first base metal layer 121A is preferably a layer containing one or more selected from, for example, chromium (Cr), titanium (Ti), tungsten (W), and palladium (Pd). The first base metal layer 121A can also be a layer made of one or more materials selected from, for example, chromium (Cr), titanium (Ti), tungsten (W), and palladium (Pd). Even in this case, it does not exclude that the first base metal layer 121A contains unavoidable impurities.

The first underlying metal layer 121A is preferably a metal film or metal oxide film of one or more metals selected from chromium (Cr), titanium (Ti), tungsten (W), and palladium (Pd). preferable.

The second base metal layer 121B has a function of enhancing the adhesion between the solder layer and other layers, and is selected from, for example, nickel (Ni), copper (Cu), platinum (Pt), and silver (Ag). Preferably, the layer contains one or more metals. From the viewpoint of particularly suppressing the cost, the second base metal layer 121B is more preferably a layer containing one or more types of metals selected from nickel (Ni) and copper (Cu).

The second base metal layer 121B can also be a layer made of one or more metals selected from, for example, nickel (Ni), copper (Cu), platinum (Pt), and silver (Ag). Also in this case, from the viewpoint of cost, the second base metal layer 121B is preferably a layer made of one or more metals selected from nickel (Ni) and copper (Cu). In any of the above cases, it is not excluded that the second base metal layer 121B contains unavoidable impurities.

When the third base metal layer is further provided, the third base metal layer is preferably a layer containing one or more selected from, for example, nickel (Ni) and gold (Au). In particular, when the third underlying metal layer is a layer containing nickel (Ni), a layer containing a nickel-boron alloy (Ni-B) or a layer made of Ni-B in order to improve the wettability of the solder It is preferable to do. By providing the third base metal layer, for example, reaction between the base metal layer 121 and the solder layer 122 can be particularly suppressed. The third base metal layer can also be a layer made of one or more metals selected from nickel (Ni) and gold (Au). Even in this case, it does not exclude that the third base metal layer contains unavoidable impurities.

The thickness of each layer constituting the base metal layer 121 is not particularly limited and can be arbitrarily selected.

For example, the thickness of the first underlying metal layer 121A is preferably 0.03 μm or more from the viewpoint of particularly enhancing the adhesion of the inorganic material to the substrate 11. The upper limit of the thickness of the first underlying metal layer 121A is not particularly limited either, but is preferably 0.2 μm or less from the viewpoint of sufficiently reducing the cost.

The thickness of the second base metal layer 121B is preferably 0.1 μm or more from the viewpoint of particularly enhancing the adhesion to the solder layer 122. The upper limit of the thickness of the second base metal layer 121B is not particularly limited either, but is preferably 2.0 μm or less from the viewpoint of sufficiently reducing the cost.

When the third underlying metal layer is also provided, its thickness is not particularly limited, but it is preferably, for example, 0.05 μm or more from the viewpoint of particularly suppressing the reaction between the underlying metal layer 121 and the solder layer 122. The upper limit of the thickness of the third base metal layer is not particularly limited either, but is preferably 1.0 μm or less from the viewpoint of sufficiently reducing the cost.

Next, the solder layer 122 will be described.

The solder layer 122 has a function of bonding the base 11 made of an inorganic material and a circuit board provided with an optical element when manufacturing an optical package, and the configuration thereof is not particularly limited.

However, 5 micrometers or more are preferable and, as for the average value of the thickness of the

solder layer

122, 15 micrometers or more are more preferable. This is because the average value of the thickness of the solder layer 122 is 5 μm or more, for example, even if the bonding surface of the circuit board to be bonded to the bonding layer 12 includes irregularities, the recesses are filled with the material of the solder layer In particular, the hermetic sealing can be enhanced.

In addition, the average value here means the value of a simple average (it may be called an arithmetic mean or an arithmetic mean). In the following, the term "average" simply means a simple average.

The upper limit of the average value of the thickness of the solder layer 122 is also not particularly limited, but is preferably 50 μm or less, and more preferably 30 μm or less. Even if the average value of the thickness of the solder layer 122 exceeds 50 μm and becomes excessively thick, no significant change occurs in the effect of the hermetic sealing property.

The average value of the thickness of the solder layer 122 is obtained by measuring the thickness of the solder layer 122 of the window material 10 at a plurality of arbitrary measurement points with a laser microscope (manufactured by Keyence Corporation, model VK-8510) It can be calculated by The number of measurement points at which the thickness of the solder layer 122 is measured to calculate the average value is not particularly limited, but for example, two or more points are preferable, and four or more points are more preferable. The upper limit of the number of measurement points is not particularly limited, but is preferably 10 or less, more preferably 8 or less, from the viewpoint of efficiency.

When calculating the average value of the thickness of the solder layer 122, for example, it is more preferable to measure the thickness at measurement points Z1 to Z8 shown in FIG. 3 and calculate the average value.

In addition, FIG. 3 is a figure shown in order to show the example of a measurement point, and is a figure corresponding to FIG. 1 (B). FIGS. 3 and 1B are views of the window member 10 as viewed from the side on which the bonding layer 12 is formed, that is, a bottom view, in which the bonding layer 12 including the solder layer 122 is an inorganic material. It has a shape arranged along the outer periphery. The bonding layer 12 including the solder layer 122 has an opening at the center, and the base 11 of the inorganic material can be seen through the opening.

As shown in FIG. 3, when the solder layer 122 has a square opening at the center and the outer shape has a square, measurement points Z1, Z3, Z1, Z3 of the central position of the corners 31A-31D of the four sides 301-304, The thickness, which is the maximum height of the solder layer, is measured at Z5 and Z7 and measurement points Z2, Z4, Z6 and Z8 at the center position of the side portions 32A to 32D, and the average value is the average value of the thickness of the solder layer 122 It is preferable to

The bottom surface shape of the solder layer is not limited to the form shown in FIG. 1 (B) and FIG. 3 and may be any shape, for example, the outer shape has a polygonal shape other than quadrilateral, etc. The openings can also be shaped correspondingly. Also in this case, for example, the thickness can be measured at each of the center positions of the corner and the side of each side, and the average value of the measured thickness can be used as the thickness of the solder layer. The corner and the side will be described later.

The deviation of the thickness of the solder layer 122, that is, the deviation from the simple average value of the thickness is preferably within ± 20 μm, and more preferably within ± 10 μm.

When making the deviation of the thickness of the solder layer 122 within ± 20 μm, the airtight sealability between the window material and the circuit board on which the optical element is disposed can be particularly enhanced when the optical package is manufactured. It is possible and preferable.

The deviation of the thickness of the solder layer 122 within ± 20 μm means that the deviation is distributed in the range of −20 μm or more and +20 μm or less.

The deviation of the thickness of the solder layer 122 can be calculated from the above-described average value of the thickness of the solder layer and the measurement value used when calculating the average value.

In addition, although the thickness of the solder layer 122 is minute depending on the method of forming the solder layer, variations may occur. Therefore, a weighted average may also be calculated for the thickness of the solder layer 122 and used as an evaluation index. When calculating the weighted average for the thickness of the solder layer 122, the weighted average of the thickness of each side included in the solder layer is calculated, and the weighted average of the thicknesses of all the sides (simple average) is calculated as the thickness of the solder layer 122 It can be a weighted average.

The weighted average of the thickness of each side measures the thickness at the center position of the corner and the side included in each side, and when the measurement point is a corner, the weighted average of the corner is calculated. By the length in the longitudinal direction, when the measurement point is a side, weight can be given by the length in the longitudinal direction of the side for which the weighted average of the side is calculated.

The corner indicates a portion where the sides of the solder layer overlap, and the side indicates a place other than that. For example, in the case of the solder layer 122 shown in FIG. 3, the solder layer 122 has a rectangular opening at the center, has a square outer shape, and has four sides of a side 301 to a side 304. The solder layer 122 shown in FIG. 3 has corner portions 31A to 31D in which the sides 301 to 304 overlap with each other.

Specifically, the corner 31A is a region surrounded by straight lines A1, A2, B1, and B2 in which the side 301 and the side 304 overlap. The corner portion 31B is an area surrounded by straight lines A3, A4, B1, and B2 in which the side 301 and the side 302 overlap. The corner 31C is a region surrounded by straight lines A3, A4, B3, and B4 in which the side 302 and the side 303 overlap. The corner portion 31D is a region surrounded by straight lines A1, A2, B3, and B4 in which the side 303 and the side 304 overlap.

The solder layer 122 shown in FIG. 3 has side portions 32A to 32D. Specifically, the side portion 32A is an area surrounded by straight lines A2, A3, B1, and B2. The side 32B is an area surrounded by straight lines A3, A4, B2, and B3. The side 32C is an area surrounded by the straight lines A2, A3, B3 and B4. The side 32D is an area surrounded by the straight lines A1, A2, B2, and B3.

In the case of taking a weighted average for the side 301, the thicknesses at the

corner portions

31A and 31B and the side portions 32A may be calculated by weighting with the length in the longitudinal direction of the side 301 of each region by the following procedure. it can. The thickness T _Z1 measured at the measurement point Z1 at the center position of the corner 31A is weighted by the length W1 in the longitudinal direction of the side 301 at the corner 31A. The thickness T _Z2 measured at the measurement point Z2 at the center position of the side portion 32A is weighted by the length L1 in the longitudinal direction of the side 301 in the side portion 32A. The thickness T _Z3 measured at the measurement point Z3 at the center position of the corner 31B is weighted by the length W2 in the longitudinal direction of the side 301 at the corner 31B. Then, the weighted average of the side 301 can be calculated by dividing the sum of the calculation results by the sum of W1, L1, and W2 used for weighting.

Similarly, the weighted average of the solder layer can be determined by calculating the weighted average of the other sides and determining the average value thereof.

In the case of the solder layer 122 shown in FIG. 4, it can be calculated by the following equation (1).
Weighted average value = [(W1 × _TZ1 + L1 × _TZ2 + W2 × _TZ3 ) / (W1 + L1 + W2) + (W3 × _TZ3 + L2 × _TZ4 + W4 × _TZ5 ) / (W3 + L2 + W4) + (W2 × _TZ5 + L1 ×) T _Z6 + W 1 × T _{Z 7} ) / (W 1 + L 1 + W 2) + (W 4 × T _{Z 7} + L 2 × T _{Z 8} + W 3 × T _{Z 1} ) / (W 3 + L 2 + W 4)] / 4 (1)
T _Zx in the above-mentioned formula (1) means the thickness of the solder layer measured at each measurement point Z x (x is any one of 1 to 8), and the same applies hereinafter. L1 and L2 in the said Formula (1) become length of each edge | side of the opening part provided in the center of the solder layer 122, as shown in FIG. Although L1 and L2 can be lengths measured at arbitrary positions, it is preferable to use an average value measured at a plurality of places. For example, L1 is preferably an average value of the lengths of one side of the opening measured at both ends and the center of the opening, that is, measured along straight lines B2, B3 and B5, for example. Similarly, L2 is preferably measured at both ends and at the center of the opening, that is, it is preferable to use, for example, an average value of one side length of the opening measured along straight lines A2, A3 and A5.

The line widths W1 to W4 of the solder layer 122 can also be measured at arbitrary positions, but it is preferable to use an average value measured at a plurality of places. For example, in the case of the line width W1, measurement at three points of a value measured along a straight line B5 passing through the longitudinal center of the side 304 and a value measured along straight lines B2 and B3 passing through both ends of the opening It is preferable to use an average value.

Depending on the method of forming the solder layer, for example, the thickness may be symmetrical. For example, when the solder layer is formed by dipping and the dip direction is known, the thickness of the solder layer becomes symmetrical about the dip direction. For example, when dipping is performed along the straight line B5 in FIG. 3, the thickness of the solder layer 122 is symmetrical about the straight line B5. For this reason, in such a case, the thickness of the solder layer 122 at the measurement points Z7, Z6, and Z5 is respectively equivalent to the thickness of the solder layer 122 at the measurement points Z1, Z2, and Z3. Therefore, the thicknesses at all the measurement points Z1 to Z8 There is no need to measure For example, the thickness can be measured at five measurement points Z1 to Z4 and Z8, and the weighted average of the thickness of the solder layer 122 can be calculated as T _Z1 = T _Z7 , T _Z2 = T _Z6 , and T _Z3 = T _Z5. . In the case of the simple average, the average value can also be determined from the values of only the same measurement points.

The weighted average value of the solder layer is not particularly limited, but is preferably 4 μm or more, and more preferably 13 μm or more. Further, the upper limit of the weighted average value of the solder layer is also not particularly limited, but for example, 70 μm or less is preferable, and 60 μm or less is more preferable.

Further, it is preferable that the deviation from the weighted average value of the solder layer, that is, the difference between the thickness at each measurement point and the calculated weighted average value be within ± 30 μm.

About the deviation of a weighted average value and a weighted average value, since a preferable reason is the same as that of the case of an average value, it is abbreviate | omitted.

The bottom surface shape of the solder layer is not limited to the form shown in FIG. 1 (B) and FIG. 3, for example, the outer shape has a polygonal shape other than quadrilateral, and the opening also has a corresponding shape. It can also be done. Also in this case, for example, the thickness is measured at the center position of the corner and the side included in each side, weighted by the length in the longitudinal direction of the side for calculating the weighted average of each area, and the weighted average of each side is calculated The weighted average of the solder layer can be calculated by calculating the average of the weighted average of the thickness of all sides.

The window material of the present embodiment can be used by bonding to a circuit board provided with an optical element, and the solder layer 122 can bond the circuit board and the window material.

An oxide film is generally present on the surface of the solder layer 122, but in order to facilitate bonding to the circuit board, the lower surface of the solder layer 122, that is, the surface of the surface facing the circuit board It is preferable that the existing oxide film be melted into the inside of the solder layer 122 melted by heating, and be thin enough to allow the melted solder layer 122 to be in contact with the upper surface of the circuit board. Although the thickness of the oxide film on the surface of the solder layer is not particularly limited, the thickness of the oxide film is preferably 10 nm or less, and more preferably 5 nm or less.

Since it is preferable that the amount of such an oxide film is small, the thickness of the oxide film can be 0 or more.

The solder layer 122 can be composed of various solders (composition for bonding).

The solder used for the solder layer 122 is not particularly limited. For example, materials having a Young's modulus of 50 GPa or less are preferable, materials having 40 GPa or less are more preferable, and materials having 30 GPa or less are more preferable.

As described above, the window material of the present embodiment can be used as a member of an optical package, but after being formed into an optical package, for example, when the optical element is turned on or off, temperature change occurs in the solder layer. There is a case. And, by setting the Young's modulus of the solder used for the solder layer to 50 GPa or less, temperature change occurs in the solder layer portion, and even if it expands or contracts, it is possible to particularly suppress destruction or the like of other members. It is from.

In addition, when the Young's modulus of the solder is 50 GPa or less, when the optical package is formed, the stress caused by the thermal expansion difference between the base 11 of the inorganic material and the circuit board provided with the optical element It is because it can be absorbed within 122 and is preferable.

The lower limit value of the preferable range of the Young's modulus of the solder used for the solder layer 122 is not particularly limited, but may be, for example, larger than 0, and 10 GPa or more is preferable from the viewpoint of enhancing the hermetic sealability.

The Young's modulus of the solder can be calculated from the results of a tensile test of the solder.

The melting point of the solder used for the solder layer 122 is preferably 200 ° C. or more, and more preferably 230 ° C. or more. This is because when the melting point of the solder is 200 ° C. or more, the heat resistance in forming an optical package can be sufficiently enhanced. However, the melting point of the solder used for the solder layer 122 is preferably 280 ° C. or less. This is to perform heat treatment when manufacturing the optical package to melt at least a part of the solder layer 122. However, when the melting point of the solder is 280 ° C. or less, the temperature of the heat treatment can be suppressed low. It is because it can control especially that damage arises in etc.

The density of the solder used for the solder layer 122 is preferably 6.0 g / cm ³ or more, and more preferably 7.0 g / cm ³ or more. This is because the airtight sealability can be particularly enhanced by setting the density of the solder used for the solder layer 122 to 6.0 g / cm ³ or more. The upper limit of the density of the solder used for the solder layer 122 is not particularly limited, but is preferably 10 g / cm ³ or less, for example.

The thermal expansion coefficient of the solder used for the solder layer 122 is preferably 30 ppm or less, and more preferably 25 ppm or less. This is because when the thermal expansion coefficient of the solder is 30 ppm or less, the optical package is used, and the shape change due to heat generated at the time of light emission of the optical element is suppressed, and breakage of the optical package can be prevented more reliably. . Although the lower limit value of the thermal expansion coefficient of the solder used for the solder layer 122 is not particularly limited, for example, 0.5 ppm or more is preferable.

The copper corrosion resistance of the solder used for the solder layer 122 is preferably 15% or less, and more preferably 10% or less. This is because when the copper corrosion resistance of the solder used for the solder layer 122 is 15% or less, the reaction with the base metal layer 121 or the like can be suppressed, which is preferable. The lower limit value of the copper corrosion resistance of the solder used for the solder layer 122 is not particularly limited, but is preferably 0 or more. In addition, copper corrosion resistance of solder can be evaluated by copper corrosion resistance evaluation.

Copper corrosion resistance can be evaluated, for example, by the following procedure.

Cut two 0.5 mm diameter copper wires to a length of about 3 mm, and immerse the surface of the two copper wires in RMA (Rosin Midly activated, weakly active rosin) type flux to remove the oxide film .

The first copper wire from which the oxide film has been removed is washed with ethanol, and the cross-sectional area S1 of the _first copper wire is measured. In addition, the cross-sectional area of a copper wire means the cross-sectional area in the surface perpendicular | vertical to the longitudinal direction of a copper wire.

Next, a second copper wire from which the oxide film has been removed is placed in the solder to be evaluated, and immersed for 60 seconds in a solder bath heated so as to have a hot water temperature of 400.degree. At this time, in order to prevent the re-generation of the oxide film of the copper wire, it is immersed in the solder bath within 60 seconds after the oxide film is removed by the flux. After immersion in a solder bath, pulling the copper wire, the end portion of the immersed side in a solder bath, polished copper wire, at a position where the copper cross section can be confirmed, for measuring the cross-sectional area S ₂ of the copper wire.

To the cross-sectional area S ₁ of the copper wire before immersion into a solder bath, compare the cross-sectional area S ₂ of the copper wire after immersion in a solder bath, to calculate the percentage of area reduction. Specifically, it can be calculated by the following equation.
(Copper corrosion resistance) = (S ₁ -S ₂ ) / S ₁ × 100
The solder constituting the solder layer is not particularly limited as described above, but contains, for example, tin, germanium, and nickel, the content of germanium is 10% by mass or less, and the content of germanium and the content of nickel It is preferable that the amount and the following formula (1) be satisfied.

[Ni] ≦ 2.8 × [Ge] ^0.3 (1)
(However, [Ni] indicates the content of nickel in mass% conversion, and [Ge] indicates the content of germanium in mass% conversion.)
According to the above-described solder, after the solder is disposed on the member to be joined, it can be easily joined to the object without the need for removing the oxide film.

The components contained in the solder that can be suitably used for the solder layer will be described below.
(Tin)
The above-mentioned solder contains tin (Sn).

Tin can reduce the difference in thermal expansion between a member to be joined, such as a circuit board or an underlying metal layer, and solder. Furthermore, by containing tin as a main component of the solder, the melting point temperature of the solder can be set to about 230 ° C., which is the melting point temperature of tin.

The above-mentioned solder can contain tin as a main component. Containing as a main component means, for example, a component contained most in the solder, and a component containing 60% by mass or more in the solder is preferable.

In particular, the content of tin in the solder is, for example, more preferably 85.9% by mass or more, still more preferably 87.0% by mass or more, and particularly preferably 88.0% by mass or more.

This is because when the tin content in the solder is 85.9% by mass or more, the effect of the thermal expansion difference between the joined member and the solder and the reduction of the melting temperature of the solder are particularly high. .

The upper limit of the content of tin in the solder is not particularly limited, and is, for example, preferably 99.9% by mass or less, more preferably 99.5% by mass or less, and still more preferably 99.3% by mass or less.

The above-described solder contains germanium and nickel in addition to tin. And by containing these components, when it apply | coats to a to-be-joined member, it can suppress that an oxide film arises on the surface of solder. Moreover, the above-mentioned solder can also contain the arbitrary components mentioned later besides germanium and nickel. For this reason, in order to fully secure content of components other than these tin, as above-mentioned, 99.9 mass% or less of content of tin is preferable.

Note that, as described later, the hermetic sealability between members to be joined can be particularly enhanced depending on the content of germanium or the like. From the viewpoint of enhancing the hermetic sealability, the content of components such as germanium other than tin in the solder is preferably at least a certain amount. For this reason, it is particularly preferable to set the upper limit value of the tin content to 98.8% by mass or less, when it is required to particularly enhance the hermetic sealability.
(germanium)
The above-mentioned solder contains germanium.

Germanium can suppress the formation of an oxide film on the surface of the solder when the solder is applied to the bonding surface of the members to be bonded. This is because, when the solder is melted to apply the solder, the germanium contained in the solder can be preferentially oxidized to suppress the oxidation of the nickel in the solder.

Although content of germanium of the above-mentioned solder is not specifically limited, 10 mass% or less is preferable, and 8 mass% or less is more preferable.

This is because if the content of germanium in the solder exceeds 10% by mass, the germanium itself forms an oxide excessively, which may in turn hinder the bonding with the member to be joined.

The lower limit of the content of germanium is not particularly limited, but is preferably more than 0.5% by mass, and more preferably 0.7% by mass or more.

When the solder is melted, the excess oxygen may be gasified to cause voids in the solder. In particular, when the solder is melted for joining in a vacuum environment, the above-mentioned gas such as oxygen expands to easily form a void in the solder. And the airtight sealing property between to-be-joined members may fall by this space | gap.

On the other hand, by increasing the content of germanium in the solder to more than 0.5% by mass, the generation of voids in the solder due to the above-described excess oxygen is suppressed, and the hermetic seal between members to be joined It is preferable because it can particularly enhance the fastness.
(nickel)
The above-mentioned solder contains nickel (Ni) as mentioned above.

When the solder is melted, the nickel contained in the solder tends to be an oxide. For this reason, when an oxide is contained in the bonding portion of the members to be bonded, for example, the bonding surface of the circuit board, the oxide of the bonding portion and the solder are easily bonded, and the solder and the oxide are included. This is because the wettability with the bonding portion is improved, and high bonding strength can be exhibited.

Although the content of nickel in the above-mentioned solder is not particularly limited, it is preferable to have a certain relationship with the content of germanium.

Specifically, it is preferable that the content [Ni] of nickel in terms of mass% and the content [Ge] of germanium in terms of mass% satisfy the following formula (1).

[Ni] ≦ 2.8 × [Ge] ^0.3 (1)
This is because, when the nickel content [Ni] in terms of mass% of solder exceeds 2.8 × [Ge] ^0.3 , the solder is melted to be applied to the bonding surface of the member to be joined, This is because a part of the solder remains in the form of particles and may not be joined.

In particular, the content [Ni] of nickel in mass% conversion and the content [Ge] of germanium in mass% conversion satisfy that [Ni] ≦ 2.4 × [Ge] ^0.3. Preferably, it is more preferable to satisfy [Ni] ≦ 2.0 × [Ge] ^0.3 .

The lower limit value of the nickel content of the above-mentioned solder is not particularly limited, and may be more than 0% by mass.

Moreover, less than 2.0 is preferable and, as for the value which remove | divided content [nickel] of nickel in mass% conversion with content [Ge] of germanium in mass% conversion, less than 1.5 is more preferable. That is, [Ni] / [Ge] <2.0 is preferable, and [Ni] / [Ge] <1.5 is more preferable.

This is because, when [Ni] / [Ge] is 2.0 or more, a nickel oxide film may be generated on the surface of the solder melted to be applied to the bonding surface of the members to be bonded. Because there is a risk of The oxide film of nickel means an oxide film containing a relatively large amount of nickel among metal components.

Further, the value obtained by dividing the nickel content [Ni] in mass% conversion by the germanium content [Ge] in mass% conversion is preferably 0.005 or more, and more preferably 0.01 or more. That is, 0.005 ≦ [Ni] / [Ge] is preferable, and 0.01 ≦ [Ni] / [Ge] is more preferable.

This is because, when [Ni] / [Ge] is less than 0.005, the solder can not hold sufficient oxygen, and when the bonding portion of the member to be bonded contains an oxide, the oxidation of the bonding portion It is because the wettability to a thing may fall and there exists a possibility of impairing the airtight sealing property between to-be-joined members.

Furthermore, the sum of the content of germanium and the content of nickel is preferably more than 1.2% by mass. This is because when the total of the content of germanium in the solder and the content of nickel is more than 1.2% by mass, the hermetic sealability between the members to be joined can be particularly enhanced.
(iridium)
The above-mentioned solder can further contain iridium (Ir).

When the above-mentioned solder contains iridium, the occurrence of voids in the solder can be reduced when the solder is melted. The reason why the solder can suppress the generation of voids when the solder is melted by containing iridium is not clear, but it is presumed that the surface tension of the molten metal can be reduced and the gas entrainment can be reduced.

Thus, since it is possible to sufficiently secure the bonding area with the member to be joined by reducing the generation of the void when the solder is melted, it is possible to enhance the bonding strength. In addition, since the occurrence of the leak path can be suppressed, the hermetic sealability between the members to be joined can be enhanced.

In addition, coarsening of the crystals of the eutectic in the solder melts and solidifies the solder, and when forming a bonding portion for bonding the members to be bonded, the elongation and strength of the bonding portion are reduced, and bonding is performed. It may cause the occurrence of cracks in parts. However, when the solder contains iridium, it is possible to suppress the coarsening of the crystal of the eutectic and to suppress the generation of the crack which is a cause of the decrease in the airtightness.

Solder is generally processed into a linear shape and used as a linear solder, but a linear solder containing coarse crystals is brittle and difficult to use. On the other hand, the above-mentioned solder can suppress the coarsening of the crystal of the eutectic in solder by containing iridium. For this reason, the above-mentioned solder can suppress that a handleability falls, even when it is set as a linear solder by containing iridium.

The eutectic contained in the solder referred to here is, for example, a Ge—Ni eutectic formed of germanium and nickel.

The content of iridium in the above-mentioned solder is not particularly limited, but is preferably 0.1% by mass or less, more preferably 0.025% by mass or less, and still more preferably 0.005% by mass or less.

If the content of iridium in the solder exceeds 0.1% by mass, an oxide film may be generated on the surface when the solder is melted, which may inhibit the bonding of the members to be joined. It is for.

In addition, when the content of iridium in the solder is 0.025% by mass or less, the airtight sealability between the members to be joined can be particularly enhanced, which is more preferable.

The lower limit value of the content of iridium is not particularly limited, and may be, for example, 0% by mass or more, preferably 0.0005% by mass or more.
(zinc)
The above-mentioned solder can further contain zinc (Zn).

When the solder contains zinc, zinc tends to be an oxide when the solder is melted. For this reason, when an oxide is contained in the bonding portion of the members to be bonded, the oxide of the bonding portion and the solder are easily bonded, and the wettability between the solder and the bonding portion containing the oxide is It becomes possible to improve and to show high joint strength.

The content of zinc in the above-mentioned solder is not particularly limited, but is preferably 0.5% by mass or less.

If the content of zinc in the solder exceeds 0.5% by mass, an oxide film may be generated on the surface when the solder is melted, which may inhibit the bonding of the members to be joined. It is for.

The lower limit value of the content of zinc is not particularly limited, and may be, for example, 0% by mass or more.
(oxygen)
And the above-mentioned solder can further contain oxygen.

Oxygen in the solder is a component that promotes bonding between the solder and the bonding portion containing the oxide when the bonding portion of the bonding member contains an oxide.

The state of oxygen contained in the solder is not particularly limited. For example, it is preferable that oxygen be contained in a molten form in the metal material of the solder. This is because at the interface between the solder and the member to be joined, the gradient of the oxygen concentration between the oxide of the joint portion of the member to be joined and the metal material in the solder becomes smooth, and the joint interface becomes strong. It is.

The method of containing oxygen in the solder is not particularly limited. For example, a method of melting and manufacturing the solder in an atmosphere containing oxygen and / or a bonding operation with a workpiece in an atmosphere containing oxygen How to do it.

In addition, it is preferable that the solder before joining a to-be-joined member has satisfied content of the oxygen in the solder mentioned later. Therefore, it is preferable to adjust the oxygen concentration by a method of melting and manufacturing the solder in an atmosphere containing oxygen.

In particular, it is more preferable that the content of oxygen in the solder described later be satisfied in any state of the solder before bonding the members to be bonded and the solder after bonding.

The content of oxygen in the solder is not particularly limited, but may be, for example, 0.0001% by mass or more, preferably 0.0007% by mass or more.

This is because the effect of enhancing the bonding strength can be sufficiently exhibited by setting the content of oxygen to be 0.0001% by mass or more.

The upper limit of the content of oxygen in the solder is not particularly limited, but may be, for example, 2% by mass or less, preferably 1% by mass or less.

This is because if the amount of oxygen contained in the solder is too large, the oxide is likely to be precipitated inside the solder, which may lower the bonding strength. Therefore, as described above, the content of oxygen in the solder is preferably 2% by mass or less.

Here, the content of oxygen in the solder means the content of oxygen contained in the inside of the solder. That is, when the oxide film is formed on the solder surface, it indicates the oxygen content in the solder after the oxide film is removed.

When measuring the oxygen amount in solder, the removal method of an oxide film is not specifically limited, For example, it can remove by processing the surface of solder with an acid etc.

The measurement of the oxygen content in the solder can be performed, for example, by the following procedures (1) to (3).
(1) As a sample for analysis, prepare 0.5 g of the produced small piece of solder.
(2) Chemical etching is performed to remove the influence of the oxide film contained on the surface of the small solder piece prepared in (1).

Specifically, a beaker containing small pieces of solder and twice-diluted hydrochloric acid is set in a water bath and heated at 80 ° C. for 12 minutes. Thereafter, decantation is carried out with degassed water and then with ethanol.
(3) Measure the oxygen concentration of the solder sample from which the oxide film has been removed in (2). The measurement of the oxygen concentration can be performed using, for example, an oxygen / hydrogen analyzer.

So far, the respective components that the above-mentioned solder can contain have been described, but the present invention is not limited to such materials. Moreover, the above-mentioned solder may contain the unavoidable component which generate | occur | produces, for example, when preparing solder. The unavoidable component is not particularly limited. However, in the case where one or more elements selected from the group consisting of Fe, Co, Cr, V, Mn, Sb, Pb, Bi, Zn, As, and Cd are contained as unavoidable components, the content of the above-mentioned element is 1 mass% or less in total is preferable, and 500 ppm or less in total is more preferable.

This is because the above-mentioned elements have the function of reducing the wettability of the solder to the joined member, and the wettability of the solder to the joined member is lowered by setting the total content of the above elements to 1% by mass or less. It is because it can control.

And, since Ga, P and B cause the generation of voids, when one or more elements selected from the group consisting of Ga, P and B are contained as unavoidable components, the total content thereof is 500 ppm or less. Preferably, 100 ppm or less is more preferable in total.

Moreover, it is preferable that the above-mentioned solder does not contain silver (Ag).

This means that silver forms an intermetallic compound (Ag ₃ Sn) with tin. And, since Ag ₃ Sn has a high melting point, when it is present on the solder surface, the wettability with the member to be joined may be reduced although it is slightly.

The phenomenon of reduced wettability with the member to be joined does not become a problem as long as the solder is bonded while removing the oxide film using a conventional ultrasonic soldering iron or the like. However, it is because it becomes a factor which inhibits joining, when joining is performed under the environment where the removal effect of an oxide film does not work without using an ultrasonic soldering iron etc.

In addition, that a solder does not contain silver means below a detection limit, when melt | dissolving solder with an acid and analyzing by ICP emission spectrometry.

Then, the solder described above, in the solder of the cross section, the eutectic product area at an arbitrary position is present in the 1.0 × 10 ⁶ μm ² in area, the circle of minimum size eutectic is contained therein When each of the eutectics is formed, two or less circles having a diameter of 220 μm or more are preferable, or one or less circle having a diameter of 350 μm or more is preferable.

Further, the above-mentioned solder has an area of 1.0 × 10 ⁶ μm ² at an arbitrary position in the cross section of the solder, and the number of eutectic substances having an area of 2000 μm ² or more is 2 or less Preferably, one or less of eutectics of 4000 μm ² or more is used.

It is preferable that the above-described solder satisfies at least one of the above-described definitions of eutectics in a predetermined region of the cross section of the solder or at least before bonding the members to be joined. In particular, the above-mentioned solder is either or both of the above-mentioned prescriptions for eutectics in a given area of the cross section of the solder, both before bonding the members to be joined and after joining the members to be joined. It is more preferable to satisfy That is, it is more preferable that the above-mentioned solder satisfies either or both of the above-mentioned prescriptions, when evaluating about the eutectic within the predetermined field of the section of solder at arbitrary timing. .

The shape of the region of 1.0 × 10 ⁶ μm ² at an arbitrary position described above is not particularly limited, and can be any shape. As a shape of the said area | region, a square, a rectangle, a polygon etc. are mentioned, for example. In the case of a square area, for example, the length of one side can be 1.0 × 10 ³ μm. Further, in the case of forming a rectangular area, the length of each side can be selected so as to secure the above-mentioned area, and for example, a rectangular shape of 400 μm × 2500 μm can be used. Even in the case of forming a polygon area, the length of each side can be selected so as to secure the above-mentioned area, and the length of each side constituting the polygon is not limited.

Examples of the eutectic contained in the above-mentioned solder include Ge—Ni eutectic formed of germanium and nickel.

As described above, the coarsening of the crystal of the eutectic in the solder melts and solidifies the solder, and when forming a joint that joins the members to be joined, the elongation and strength of the joint are determined. It may lower and cause cracks at the joint. However, when the eutectic in the cross section of the solder satisfies the above conditions, it can be said that the coarsening of the crystal of the eutectic can be suppressed, and the generation of the crack causing the airtightness deterioration can be suppressed.

In addition, although the solder can be processed into a linear shape and can be used as a linear solder, when the eutectic in the cross section of the solder satisfies the above conditions, the coarsening of the crystal of the eutectic in the solder is suppressed It can be made to have sufficient handleability in the case of linear solder.

Examples of the solder that can be suitably used for the solder layer 122 include tin (Sn) -antimony (Sb) -based solder and the like in addition to the above-mentioned solder.

The content of each component of the tin-antimony-based solder is not particularly limited. For example, the content of antimony is preferably 1% by mass or more. Antimony has the function of raising the solidus temperature in a tin-antimony solder, and by setting the content of the antimony to 1% by mass or more, such an effect can be particularly exhibited, which is preferable.

Although the upper limit of content of antimony is not specifically limited, For example, it is preferable to set it as 40 mass% or less. This is because by setting the content of antimony to 40% by mass or less, it is possible to prevent the solidus temperature from becoming excessively high, and to obtain a solder suitable for mounting electronic components.

The tin-antimony-based solder can contain tin. Tin can reduce the difference in thermal expansion between a member to be joined, such as a circuit board or an underlying metal layer, and solder. Furthermore, by containing tin as a main component of the solder, the melting point temperature of the solder can be set to about 230 ° C., which is the melting point temperature of tin.

The tin-antimony-based solder can also be composed of antimony and tin, and in this case, the remainder excluding antimony can be composed of tin.

The tin-antimony-based solder may contain any additive component other than antimony and tin, and may contain, for example, one or more selected from silver (Ag), copper (Cu) and the like. Silver and copper, like antimony, have the function of raising the solidus temperature of the solder. In this case, the balance other than antimony and any additional components can be made of tin.

Although a configuration example of solder that can be suitably used for the solder layer 122 has been described, the solder used for the solder layer 122 of the window member 10 of the present embodiment is not limited to such solder as described above is there.

The shape of the bonding layer 12 is not particularly limited. For example, as shown in FIG. 1 (B), the view from the side of the window material 10 on which the bonding layer 12 is formed, that is, the solder layer in the bottom view The bonding layer 12 including 122 may be disposed along the outer periphery of the inorganic material base 11. The bonding layer 12 including the solder layer 122 has an opening at the center, and the base 11 of the inorganic material can be seen through the opening. In FIG. 1B, the base 11 made of an inorganic material is larger than the bonding layer 12 including the solder layer 122, but the present invention is not limited to this. For example, the outer periphery of the base material 11 of an inorganic material and the outer periphery of the bonding layer 12 including the solder layer 122 may be configured to coincide with each other.

In FIG. 1B, the solder layer 122 located on the outermost surface of the bonding layer 12 is shown, but a plane perpendicular to the stacking direction (vertical direction in FIG. 1A) of each layer of the bonding layer 12 The cross-sectional shape of the bonding layer 12 is preferably the same regardless of the layer.

Although the manufacturing method of the window material of this embodiment is not specifically limited, For example, the following processes can be included.

Substrate preparation step of preparing a substrate of inorganic material.
A bonding layer forming step of forming a bonding layer on one surface of a substrate of an inorganic material.
Although the specific operation of the substrate preparation step is not particularly limited, for example, the substrate of the inorganic material can be cut to a desired size, or can be processed to have a desired shape of the substrate of the inorganic material. . In addition, when arrange | positioning an anti-reflective film in the surface of the base | substrate of an inorganic material, an anti-reflective film can also be formed at this process. The film formation method of the antireflective film is not particularly limited. For example, the film can be formed by a dry method or a wet method, and in the case of the dry method, a vapor deposition method, a sputtering method, an ion plating method, etc. The film can be formed by one or more methods selected from the above. In the case of a wet method, film formation can be performed by one or more methods selected from an immersion method, a spray coating method, and the like.

The bonding layer forming step can include, for example, a base metal layer forming step of forming a base metal layer and a solder layer forming step.

In the base metal layer forming step, the base metal layer can be formed on one surface of the inorganic material base. The method for forming the base metal layer is not particularly limited, and can be arbitrarily selected according to the type of the base metal layer to be formed. For example, the film can be formed by the dry method or the wet method, and in the case of the dry method, the film can be formed by one or more methods selected from the vapor deposition method, the sputtering method, the ion plating method and the like. . In the case of a wet method, film formation can be performed by one or more methods selected from electrolytic plating, electroless plating, printing, and the like.

As described above, the base metal layer can be composed of a plurality of layers, and the layers can be formed by any method.

In the solder layer forming step, the solder layer can be formed on one surface of the inorganic material base or on the base metal layer. The method for forming the solder layer is not particularly limited, and may be, for example, one or more selected from dip method, coating method using dispenser, printing method, laser metal deposition method, method using solder wire, etc. .

In the dip method, the solder used as the raw material of the solder layer is melted in the solder melting bath, and the member forming the solder layer, for example, the portion forming the solder layer of the base of the inorganic material on which the base metal layer is disposed This is a method of forming a solder layer by dipping in molten solder in a melting tank.

In the coating method using a dispenser, for example, molten solder is supplied from a dispenser to which a syringe is connected to a member for forming a solder layer, for example, a portion for forming a solder layer of an inorganic material base on which an underlying metal layer is disposed; It is a method of forming a solder layer.

The printing method is a method of forming a solder layer by printing solder in a paste form on a portion of a base of an inorganic material on which a base metal layer is disposed, such as a member for forming a solder layer. A heat treatment can also be performed after printing if necessary.

The laser metal deposition method supplies powdery solder to a member for forming a solder layer, for example, a portion for forming a solder layer of an inorganic material base on which an underlying metal layer is disposed, and after melting the solder with a laser This is a method of forming a solder layer by cooling.

The method using a solder wire uses a wire-shaped or linear processed solder, for example, a member for forming a solder layer by an automatic soldering robot or the like, for example, a solder layer of an inorganic material substrate on which an underlying metal layer is disposed. Is a method of supplying a melted solder to a portion forming the solder layer to form a solder layer.

The manufacturing method of the window material of this embodiment can also have an optional step as needed.

The bonding layer can be formed to have a desired shape on one surface 11 a of the inorganic material base 11 as described with reference to FIGS. 1A and 1B.

Therefore, in the method of manufacturing the window material of the present embodiment, after forming the bonding layer by, for example, the base metal layer forming step and the solder layer forming step, a pattern is formed so that the bonding layer has a desired shape. It can also have a step of In the patterning step, for example, a resist corresponding to the pattern to be formed is disposed on the exposed surface of the solder layer, and a portion of the solder layer and the base metal layer not covered with the resist is removed by etching or the like. It can be patterned. A resist removal step may be performed to remove the resist after the patterning step.

In the case where the base metal layer includes a plurality of layers, after forming a part of the layer contained in the base metal layer, a patterning step is carried out, and a part of the layer contained in the formed base metal layer Can also be patterned. Then, after the patterning step, a resist removing step of removing the resist may be performed, and then the remaining underlying metal layer may be formed on the patterned underlying metal layer.

Further, for example, in the method of manufacturing the window material of the present embodiment, the resist arrangement is performed in which the resist is disposed in the portion where the underlying metal layer and the solder layer are not formed before performing the underlying metal layer forming step It can also have steps. By forming the base metal layer and the solder layer after forming the resist, the base metal layer and the solder layer can be formed only in the portion corresponding to the pattern to be formed. In this case, it is possible to have a resist removing step of removing the resist after the solder layer forming step.

In addition, when a plurality of bonding layers corresponding to each window material are formed on a plurality of inorganic material substrates (materials before cutting) so that a plurality of window materials can be manufactured simultaneously, It may also have a cutting step to cut the substrate. The cutting method is not particularly limited, and a cutting method in accordance with the substrate of the inorganic material, such as a cutting method using the above-described laser light, can be adopted. In the case where the bonding layer is continuously formed in the adjacent window members, that is, in the case where the bonding layer is disposed on the cutting line, the bonding layer can also be cut in the cutting step.

Note that, as an optical package, a base of an inorganic material or the like can be cut together with a circuit substrate to be separated.

According to the window material of the present embodiment described above, since the volume ratio of gold in the bonding layer is suppressed, the window material can be provided with reduced cost.
[Optical package]
Next, one configuration example of the optical package of the present embodiment will be described.

The optical package of the present embodiment can have the window material described above and a circuit board provided with an optical element.

A configuration example of the optical package of the present embodiment will be described with reference to FIG.

FIG. 4 schematically shows a cross-sectional view in a plane parallel to the stacking direction of the window material of the optical package of the present embodiment and the circuit board provided with the optical element. In FIG. 4, the window material 10 and the circuit board 41 are described separately so that they can be distinguished. However, in the optical package 40, both members are joined and integrated.

As described above, the optical package 40 of the present embodiment includes the window member 10 described above and the circuit board 41 provided with the optical element 42.

The window member 10 has already been described, so the same reference numerals as in FIG.

The circuit board 41 is not particularly limited, and various circuit boards provided with the insulating base material 411 and wiring (not shown) for supplying power to the optical element 42 can be used.

However, when the window material 10 is joined, the circuit substrate 41 has the insulating base material 411 made of ceramic in order to improve the airtight sealability in the space surrounded by the window material 10 and the circuit substrate 41. Is preferred.

Here, the ceramic material used for the insulating base material 411 of the circuit board 41 is not particularly limited. For example, alumina (aluminum oxide, Al ₂ O ₃ ), aluminum nitride (AlN), LTCC (Low Temperature Co-fired Ceramics) Etc.).

The shape of the insulating base material 411 of the circuit board 41 is not particularly limited, but in the case of the optical package 40, the optical element 42 is disposed between the base 11 of the inorganic material and the insulating base material 411 and a bonding portion described later. It is preferable to be configured to be able to form a closed space in the For this reason, it is preferable that the insulating base material 411 has an opening at the central portion of the upper surface 411a and has a recess 411A which is a non-through hole including the opening. The upper surface of the insulating base material 411 is a surface facing the window material 10 in the case of forming an optical package, and can also be said to be a surface on the side to be joined to the window material 10.

The wall portion 411B surrounding the concave portion 411A relates to the joint layer 12 and the circuit board in order to support both the joint layer 12 of the window material 10 and the base metal layer for circuit board described later when the optical package is used. It can have a shape corresponding to the underlying metal layer.

Furthermore, the circuit board 41 can have the circuit board base metal layer 412 on the top surface 411a of the insulating base 411 and on the top surface of the wall portion 411B.

The base metal layer for circuit board 412 can have the function of enhancing the adhesion between the insulating base material 411 of the circuit board 41 and the window material 10. The specific configuration of the circuit board base metal layer 412 is not particularly limited. For example, from the side of the insulating substrate 411 of the circuit board 41, the first circuit board base metal layer 412A, the second circuit board base metal layer 412B The third circuit board base metal layer 412C may have a layered structure in which the layers are stacked in this order. Although the example in which the base metal layer for circuit board 412 is composed of three layers is shown here, it is not limited to such a form, and it may be composed of one layer, two layers, or four or more layers.

When the base metal layer for circuit board 412 is formed of three layers as described above, for example, the base metal layer for first circuit board 412A is made of the same metal as the metal used to form the wiring (circuit) in the circuit board 41. It is preferable to comprise. For example, the first circuit board base metal layer 412A can be a layer including one or more metals selected from copper (Cu), silver (Ag), and tungsten (W). The first circuit board underlying metal layer 412A can also be a layer made of one or more metals selected from copper (Cu), silver (Ag), and tungsten (W). Even in this case, it does not exclude that the first circuit board underlying metal layer 412A contains unavoidable impurities.

The second circuit board base metal layer 412B can be a layer that prevents the alloying of a third circuit board base metal layer 412C described later and the first circuit board base metal layer 412A, for example, nickel. It can be a layer containing (Ni). The second circuit board base metal layer 412B can also be a layer made of nickel (Ni). Even in this case, it does not exclude that the second circuit board underlying metal layer 412B contains unavoidable impurities.

The third circuit board base metal layer 412C can be a layer for preventing the oxidation of the second circuit board base metal layer 412B, and can be, for example, a layer containing gold (Au). The third circuit board base metal layer 412C can also be a layer made of gold (Au). Even in this case, it does not exclude that the third circuit board base metal layer 412C contains unavoidable impurities.

The thickness of each layer constituting the circuit board base metal layer 412 is not particularly limited and can be arbitrarily selected.

The thickness of the first circuit board underlying metal layer 412A is preferably, for example, 1 μm or more. The upper limit of the thickness of the first circuit board underlying metal layer 412A is not particularly limited either, but is preferably 20 μm or less from the viewpoint of sufficiently reducing the cost.

The thickness of the second circuit board base metal layer 412B is preferably 1 μm or more from the viewpoint of particularly suppressing alloying of the first circuit board base metal layer 412A and the third circuit board base metal layer 412C. The upper limit of the thickness of the second circuit board underlying metal layer 412B is not particularly limited either, but is preferably 20 μm or less from the viewpoint of sufficiently reducing the cost.

The thickness of the third circuit board base metal layer 412C is preferably 0.03 μm or more from the viewpoint of particularly preventing the oxidation of the other circuit board base metal layers. The upper limit of the thickness of the third circuit board underlying metal layer 412C is not particularly limited either, but from the viewpoint of sufficiently reducing the cost, 2.0 μm or less is preferable, and 0.5 μm or less is more preferable.

The shape of the base metal layer 412 for circuit board is not particularly limited either, but in the case of the optical package 40, the bonding layer 12 of the window material 10 and the bonding layer 12 will be described later. It is preferred to have a corresponding shape. Specifically, the bonding layer 12 of the window material 10 and the base metal layer for circuit board 412 have a cross-sectional shape in a plane perpendicular to the laminating direction (vertical direction in FIG. 4) of both members when forming an optical package. The same shape is preferred.

The method for forming the circuit board base metal layer 412 is not particularly limited, and can be arbitrarily selected according to, for example, the type of the circuit board base metal layer 412 to be formed. For example, the film can be formed by the dry method or the wet method, and in the case of the dry method, the film can be formed by one or more methods selected from the vapor deposition method, the sputtering method, the ion plating method and the like. . In the case of a wet method, film formation can be performed by one or more methods selected from electrolytic plating, electroless plating, printing, and the like.

As described above, the base metal layer for circuit board can be composed of a plurality of layers, and the layers can be formed by any method.

It does not specifically limit about the optical element 42 arrange | positioned to the circuit board 41, For example, light emitting elements, such as a light emitting diode, a light receiving element, etc. can be used.

When the optical element 42 is a light emitting element, the wavelength range of light emitted by the light emitting element is not particularly limited. Therefore, for example, a light emitting element that emits light of an arbitrary wavelength range selected from the range of ultraviolet light to infrared light, that is, light of an arbitrary wavelength range selected from the range of 200 nm to 1 mm, for example It can be used.

However, according to the optical package of the present embodiment, the base of the window material, which is a member that transmits light from the light emitting element, is not the transparent resin base but the base 11 of the inorganic material. For this reason, compared with the case where a transparent resin substrate is used for the substrate of the window material, the hermetic sealing property can be enhanced, and furthermore, the deterioration of the window material due to the light from the light emitting element can be suppressed. For this reason, when the optical element is a light emitting element, the optical package of the present embodiment is highly effective particularly when a light emitting element that is particularly required to be airtight or a light emitting element that emits light that easily deteriorates in resin. It is possible to exert As a light emitting element that is particularly required to be airtight, for example, a light emitting element that emits UV-C, which is light in a wavelength range of 200 nm or more and 280 nm or less. Moreover, as a light emitting element which emits light in which deterioration of a resin is easily progressed, a light emitting element which emits light with high output such as a laser can be mentioned. Therefore, when the optical element 42 is a light emitting element, a light emitting element emitting UV-C, a laser or the like can be preferably used as the light emitting element from the viewpoint of exhibiting a particularly high effect.

The base 11 of the inorganic material of the window material 10 and the insulating base 411 of the circuit board 41 can be bonded by the bonding portion 43. The bonding portion 43 can have the bonding layer 12 of the window material 10 and the base metal layer 412 for circuit board of the circuit board 41, as shown in FIG. The bonding portion 43 can also be configured of the bonding layer 12 and the base metal layer 412 for circuit board.

The configuration of the bonding portion 43 is not particularly limited, but from the viewpoint of cost, the volume ratio of gold in the bonding portion is preferably 5% or less, more preferably 4% or less.

Since the bonding portion 43 can contain no gold, the volume ratio of gold in the bonding portion can be 0 or more.

Each layer such as the above-described solder layer included in the bonding portion 43 and the base metal layer can be formed with a substantially uniform thickness. Therefore, for example, when a gold-containing layer is present in the bonding portion 43 as a gold layer made of gold, the volume ratio of gold is the ratio of the thickness of the gold layer to the thickness of the bonding portion 43. It can also be done. When the gold-containing layer also contains a component other than gold, the gold content in the gold-containing layer is in proportion to the thickness of the gold-containing layer in the thickness of the bonding portion 43. It can also be a value obtained by multiplying

In the case where the volume ratio of gold in the joint is calculated using the thickness of each layer as described above, the average value of the simple average can be used as the thickness of the solder layer.

According to the optical package of the present embodiment described above, since the above-described window material is used, it is possible to provide an optical package with reduced cost.

The manufacturing method of the optical package of this embodiment is not particularly limited, and can be manufactured by any method.

The manufacturing method of the optical package of the present embodiment can have, for example, the following steps.

A circuit board preparation step of preparing a circuit board provided with an optical element.

A bonding step of arranging a window material on a circuit board and bonding the window material and the circuit board.

In the circuit board preparation step, an optical element can be disposed on a circuit board manufactured by an ordinary method, and a circuit board provided with the optical element can be prepared. In addition, when separating into pieces after completion | finish of a joining process, the circuit board before a cutting | disconnection with which several circuit boards were integrated can be prepared in a circuit board preparatory process.

And in a joining process, a window material can be arranged on a circuit board, and a window material and a circuit board can be joined. Although the specific method of bonding is not particularly limited, for example, first, in the optical package 40 shown in FIG. 4, the exposed lower surface 12 a of the bonding layer 12 and the exposed upper surface 412 a of the base metal layer 412 for circuit board are directly It can be superimposed to make contact. Then, for example, the solder layer 122 is heated while being pressed from the other surface 11b of the inorganic material base 11 of the window material 10 toward the circuit board 41 side, that is, along the block arrow B in the figure. The window material 10 and the circuit board 41 can be joined by melting at least a part of and then cooling.

In the bonding step, the oxide film present on the surface of the lower surface 12 a of the bonding layer 12 dissolves into the inside of the solder layer 122 melted by heating, and the melted solder layer 122 with respect to the upper surface 412 a of the base metal layer 412 for circuit board. Is preferably thin enough to be in contact. Although the thickness of a specific oxide film is not limited, 10 nm or less is preferable and, as for the thickness of an oxide film, 5 nm or less is more preferable.

The method of pressing the inorganic material base 11 is not particularly limited. For example, a method using pressing means having a pressing member in contact with the inorganic material base 11 and an elastic body such as a spring that applies pressure to the pressing member The method etc. which use a weight are mentioned.

In the optical package obtained after the bonding step, in the case where the inside of the region sealed by the window member 10 and the circuit board 41 is to be a predetermined atmosphere, the atmosphere for performing the heat treatment may be set to the predetermined atmosphere. preferable. For example, an atmosphere selected from an air atmosphere, a vacuum atmosphere, an inert atmosphere, and the like can be used. The inert atmosphere can be an atmosphere containing one or more kinds of gases selected from nitrogen, helium, argon and the like.

In the bonding step, the conditions for heat treatment are not particularly limited, and it is preferable to heat, for example, the melting temperature of the solder of the solder layer or more. However, if the substrate is heated rapidly, thermal stress may be applied to the base of the inorganic material, which may cause cracking or the like. For example, after raising the temperature to the first heat treatment temperature which is 50 ° C or more and less than the melting point of the solder It is preferable to hold at the first heat treatment temperature for a fixed time. Although the holding time at the first heat treatment temperature is not particularly limited, for example, 30 seconds or more is preferable, and 60 seconds or more is more preferable. However, from the viewpoint of productivity, the holding time at the first heat treatment temperature is preferably 600 seconds or less.

After holding for a fixed time at the first heat treatment temperature, it is preferable to further raise the temperature to a second heat treatment temperature which is a temperature equal to or higher than the melting point of the solder of the solder layer. The second heat treatment temperature is preferably the melting point + 20 ° C. or higher of the solder in order to sufficiently join the window member 10 and the circuit board 41, and the second heat treatment temperature is disposed on the circuit board when the second heat treatment temperature is excessively high. The second heat treatment temperature is preferably 300 ° C. or less, for example, because the optical element may be damaged by heat. Although the time to hold | maintain at 2nd heat processing temperature is not specifically limited, In order to fully join the window material 10 and the circuit board 41, 20 second or more is preferable. However, in order to more reliably suppress the adverse effect of heat on the optical element, the time of holding at the second heat treatment temperature is preferably one minute or less.

After the heat treatment at the second heat treatment temperature, the bonding process can be completed by cooling to room temperature, for example, 23 ° C.

The manufacturing method of the optical package of this embodiment can have optional steps as needed. For example, when a non-divided circuit board in which a plurality of circuit boards are integrated is subjected to a bonding step, it may have a cutting step. The cutting method used in the cutting step is not particularly limited, and it can be cut by any method. The circuit board and the window material can be simultaneously cut and separated by the cutting method using the laser light described in the description of the window material. Also, multiple cutting methods can be combined.

The present invention will be described with reference to specific examples, but the present invention is not limited to these examples.

First, evaluation methods of the window material and the optical package manufactured in the following embodiments will be described.
(Airtightness test)
With respect to the optical package using the window material produced in the following examples, an airtightness test was carried out immediately after preparation or after a reflow treatment and a heat cycle test were conducted under predetermined conditions, and the airtight sealing characteristics were evaluated. .

The tightness test was conducted according to JIS Z 2331: 2006, and specifically, it was conducted according to the following procedure.

First, the optical package to be evaluated was placed in a pressure vessel, and held for 2 hours in a pressure vessel under pressure conditions such that helium (He) was 5.1 atm (pressure process). ).
After completion of the pressurizing step, the optical package to be evaluated was taken out from the inside of the pressurized container, and within one hour after taking it out, the leakage amount of helium (He) was measured in the vacuum container (helium leakage amount measuring step).
It was judged as pass when the leak rate (He leak rate) of helium measured in the helium leak amount measurement process is 4.9 × 10 ⁻⁹ Pa · m ³ / s or less (judgment process). In the determination step, if the He leak rate is larger than 4.9 × 10 ⁻⁹ Pa · m ³ / s, it is determined as a failure.
Example 1
(Window material)
The window material shown to FIG. 1 (A) and FIG. 1 (B) was produced.

Specifically, a disk-shaped plate made of quartz having a diameter of 100 mm and a thickness of 0.5 mm was prepared as a material before cutting the substrate of the inorganic material (substrate preparing step).

Then, a bonding layer was formed on one surface of the pre-cutting material of the base of the inorganic material by the following procedure (bonding layer forming step).

First, by ion beam evaporation, a first underlying metal layer and a second underlying metal layer are formed in order from the material side before the cutting of the inorganic material substrate on the entire surface of the material of the inorganic material before cutting. The film was formed (underlying metal layer forming step).

As the first base metal layer, a chromium (Cr) layer having a thickness of 0.03 μm was formed, and as the second base metal layer, a copper (Cu) layer having a thickness of 0.2 μm was formed.

Next, after applying a resist on the surface opposite to the surface facing the first base metal layer of the second base metal layer, that is, the entire surface on the exposed surface, the resist is exposed using ultraviolet light and then developed. By doing this, a patterned resist was placed (resist placement step). The patterned resist has a rectangular shape in a cross section in a plane parallel to one surface of the base material of the inorganic material before cutting, and has a shape having a rectangular opening at the center.

Then, a portion of the first base metal layer and the second base metal layer which is not covered by the resist is etched with an etching solution and patterned, and then the resist is removed (resist removing step).

Next, a 0.8 [mu] m thick nickel (Ni) layer was formed as a third underlying metal layer on the patterned first underlying metal layer and the second underlying metal layer by electroless Ni plating. Thus, a patterned base metal layer including the first base metal layer, the second base metal layer, and the third base metal layer was formed.

Next, a solder layer was formed on the base metal layer. The solder used for the solder layer was previously manufactured by the following procedure.

The components contained in the solder are weighed, mixed, and melted so that 97.499 mass% of Sn, 1.5 mass% of Ge, 1.0 mass% of Ni, and 0.001 mass% of Ir. Once make the raw material alloy. Then, after melting this raw material alloy, it was poured into a mold to prepare a solder.

Then, the solder used as the raw material of the solder layer is melted in the solder melting tank, and the portion forming the solder layer of the inorganic material base on which the above-mentioned base metal layer is disposed is melted in the solder melting tank. After dipping, the solder layer was formed by cooling (solder layer forming step).

The above-mentioned solder used for forming the solder layer had a melting point of 230 ° C., a density of 7.3 g / cm ³ , and a coefficient of thermal expansion of 22.9 ppm. In addition, copper corrosion resistance was 7.47%.

The melting point was measured by raising the temperature at 10 ° C./min using a DSC (Model: DSC-60, manufactured by Shimadzu Corporation). The density was measured by the Archimedes method.

The thermal expansion coefficient was measured using a vertical thermal expansion meter (manufactured by Vacuum Riko, model: DL-7000 type). The measurement was performed by raising the temperature at 5 ° C./min in a temperature range from 23 ° C. to 200 ° C. in an argon atmosphere.

The copper corrosion resistance was evaluated by the following procedure.

Cut two 0.5 mm diameter copper wires to a length of about 3 mm, and immerse the two copper wires in RMA (Rosin Midly activated, weakly active rosin) type flux to remove surface oxide film .

Next, the second copper wire from which the oxide film has been removed is immersed for 60 seconds in a solder bath in which the solder is placed and heated to a temperature of 400 ° C. At this time, in order to prevent the re-generation of the oxide film of the copper wire, it is immersed in the solder bath within 60 seconds after the oxide film is removed by the flux. After immersion in a solder bath, pulling the copper wire, the end portion of the immersed side in a solder bath, polished copper wire, at a position where the copper cross section can be confirmed, for measuring the cross-sectional area S ₂ of the copper wire.

To the cross-sectional area S ₁ of the copper wire before immersion into a solder bath, compare the cross-sectional area S ₂ of the copper wire after immersion in a solder bath, to calculate the percentage of area reduction. Specifically, it was calculated by the following equation.
(Copper corrosion resistance) = (S ₁ -S ₂ ) / S ₁ × 100
When copper corrosion resistance was evaluated, a digital microscope (model: VHX-900 manufactured by KEYENCE CORPORATION) and image processing software attached to the digital microscope were used to measure the cross-sectional area of the copper wire.

Moreover, about the obtained said solder, when Young's modulus was computed from the tension test result, it has confirmed that it was 20 GPa. For the tensile test, the test piece of JIS 14A was tested at a tensile speed of 3 mm / min using a tensile tester (Autograph AGX-100 kN manufactured by Shimadzu Corporation).

The average value of the thickness of the solder layer and the method of calculating the weighted average value will be described with reference to FIG. FIG. 3 is a view shown to explain measurement points, and corresponds to FIG. 1 (B). In the present embodiment, as described above, the bonding layer including the solder layer is formed on one surface of the base material of the inorganic material before cutting to correspond to the plurality of window members. Therefore, the thickness of the solder layer was evaluated by arbitrarily selecting the solder layer contained in one window material by cutting and singulating. Therefore, FIG. 3 shows the solder layer 122 contained in one window material after singulation used for the measurement, and the base 11 of the inorganic material.

When singulated, the solder layer 122 has a strip shape along the outer periphery of the inorganic material base 11 in a cross section perpendicular to the laminating direction of the inorganic material base 11 and the solder layer 122.

The solder layer was formed by the dip method as described above, and was introduced into the solder melting tank along the straight line B5 in FIG. Therefore, the thickness of the solder layer is symmetrical about the straight line B5.

Therefore, the thickness of the solder layer is measured at five points of measurement points Z1, Z2, Z3, Z4 and Z8 in FIG. 3 using a laser microscope (model: VK-8510 manufactured by Keyence Corporation), and measurement points Z5 to Regarding the thickness T _{Zx at} Z7, T _Z1 = T _Z7 , T _Z2 = T _Z6 , and T _Z3 = T _Z5 . Then, when the average value of the thickness of eight measurement points Z1 to Z8 was calculated, the simple average was 29.31 μm.

The weighted average value of the solder layer 122 was calculated by the formula (1) described above using the measured values at the thicknesses T _Z1 to T _Z4 and T _Z8 at the measurement points Z1, Z2, Z3, Z4, and Z8. By the way, it was confirmed that the weighted average was 20.14 μm.

As described above, since the thickness of the solder layer is symmetrical about the straight line B5, T _Z1 = T _Z7 , T _Z2 = T _Z6 , T _Z3 = T _Z also when calculating the weighted average. Calculation is performed as _Z5 . The formula (1) has already been described, so the description is omitted here.

The length L1 of one side of the opening was measured at both ends and the center of the opening, that is, the average of the lengths of one side of the opening measured along straight lines B2, B3, and B5. The length L2 of one side of the opening was similarly measured at both ends and the center of the opening, that is, the average value of the length of one side of the opening measured along straight lines A2, A3 and A5.

The average value of the line widths measured at a plurality of points was also used for each line width W1 to W4 of the solder layer. In the case of the line widths W1 and W2, three points: a value measured along a straight line B5 passing through the longitudinal center of the

sides

304 and 302 and a value measured along straight lines B2 and B3 passing through both ends of the opening The average value of the measured value in each was used. In the case of the line widths W3 and W4, three points: a value measured along a straight line A5 passing through the longitudinal center of the

sides

301 and 303, and a value measured along straight lines A2 and A3 passing through both ends of the opening The average value of the measured value in each was used.

According to the above procedure, it can be confirmed that the maximum deviation of the thickness of the solder layer from the simple average, ie, the maximum deviation is 10 μm, and the maximum deviation from the weighted average, ie, the maximum deviation is 19 μm. The

After forming the solder layer 122, as shown in FIG. 5, on one surface of the base material of the inorganic material before cutting 51, a bonding layer 52 patterned is formed to correspond to a plurality of window members. The obtained substrate 50 is obtained. Then, the laser light is focused at an arbitrary position in the thickness direction of the substrate 51 of the inorganic material before cutting, and the laser light irradiation position is scanned along the outer shape of the patterned bonding layer 52, and then the laser light The material 51 before cutting of the substrate of the inorganic material was cut by applying a force so that the location where the focal point of the light spot passed was the fulcrum. The laser beam was scanned once along the line to cut. Therefore, as shown in FIG. 2, the side surface of the singulated inorganic material base 11 has a linear pattern 111 along the outer periphery of one surface 11a and the other surface 11b.

According to the above steps, as shown in FIG. 1B, the solder layer 122 is along the outer periphery of the base 11 of the inorganic material in the view from the side of the window material 10 where the bonding layer 12 is formed, that is, the bottom view. It has a square-shaped opening at the center, and the base 11 of the inorganic material can be seen through the opening. Although FIG. 1B shows the solder layer 122 positioned on the outermost surface, the cross-sectional shape of the bonding layer 12 in a plane parallel to the one surface 11 a of the base 11 of the inorganic material is shown in FIG. It has the same shape as the solder layer 122 shown in FIG.

The bonding layer 12 composed of the base metal layer 121 and the solder layer 122 is formed along the outer periphery of the inorganic material base 11 as described above, and the outer shape is 5 mm square, and the line width all around the same value The line widths W1 to W4 (see FIG. 3) are all 0.65 mm.

The window material was manufactured by the above process.

In addition, since the window material 10 does not contain the layer containing gold, the volume ratio of gold in the bonding layer is zero. Therefore, it has been confirmed that the cost of the bonding material can be significantly reduced to about 25% as compared with the window material using the conventional AuSn alloy.

In addition, when the thickness of the oxide film on the surface of the solder layer 122 of the window material 10 is measured using an XPS measuring device (Quantera SXM (manufactured by ULVAC-PHI)), the thickness of the oxide film is 5 nm It could be confirmed.
(Optical package)
The optical package 40 shown in FIG. 4 was manufactured using the window material and the circuit board 41 provided with the optical element 42.

As the circuit board 41, the insulating base material 411 is made of alumina (aluminum oxide) which is a rectangular solid of 5.8 mm square and 1.28 mm in height, and has wiring not shown Was used. The insulating base material 411 of the circuit board 41 has an opening at the center of the upper surface 411a, and has a recess 411A which is a non-through hole including the opening. The recess 411A is configured such that the optical element 42 can be disposed at the bottom thereof. The upper surface 411 a of the insulating base material 411 is a surface facing the window material 10 when the optical package 40 is formed. In addition, the opening is a square, and the recess 411A is a square columnar hollow (square cylinder) surrounded by the wall 411B.

The circuit board 41 has a base metal layer 412 for circuit board on the upper surface 411 a of the insulating base 411 so as to surround the opening and along the outer periphery of the upper surface 411 a of the insulating base 411. ing.

As the circuit board base metal layer 412, the first circuit board base metal layer 412A, the second circuit board base metal layer 412B, and the third circuit board base metal layer 412C are laminated in this order from the insulating base 411 side. Layer structure.

A silver (Ag) layer with a thickness of 10 μm is used as the first circuit board base metal layer 412A, and a nickel (Ni) layer with a thickness of 5 μm is used as the second circuit board base metal layer 412B. As the metal layer 412C, a gold (Au) layer having a thickness of 0.4 μm was formed.

The base metal layer for circuit board 412 has a shape corresponding to the bonding layer 12 of the window material 10. Specifically, the cross-sectional shape in a plane perpendicular to the stacking direction (vertical direction in FIG. 4) of the bonding layer 12 of the window material 10 and the base metal layer 412 for circuit board is the bonding layer 12 and the base for circuit board It was configured to have the same shape as the metal layer 412. Therefore, the base metal layer for circuit board 412 has an outer diameter of 5 mm square and a line width of 0.65 mm.

An optical element (manufactured by OptoSupply, model: OSBL1608C1A) is disposed at the bottom of the recess 411A, and is connected to a wire (not shown).

And the window material 10 and the circuit board 41 provided with the optical element 42 were joined according to the following procedures, and the optical package 40 was manufactured (joining process).

First, the upper surface 412a of the base metal layer 412 for the circuit board of the circuit board 41 provided with the optical element 42 and the lower surface 12a on the solder layer 122 side of the bonding layer 12 of the window member 10 face each other and are in contact with each other. did.

And along the block arrow B by the pressing means provided with a pressing member in contact with the base 11 of the inorganic material on the other surface 11b of the base 11 of the inorganic material of the window 10 and a spring applying pressure to the pressing member. It placed in the heat processing furnace in the state which applied pressure.

Next, the atmosphere in the heat treatment furnace was set to a vacuum atmosphere, and the temperature was raised from 23 ° C. to 80 ° C., which is the first heat treatment temperature, and held for 300 seconds. Next, the temperature was raised to 280 ° C., which is the second heat treatment temperature, and held for 30 seconds, after which the heater was turned off and cooled to 23 ° C.

The optical package was manufactured by the above procedure.

The bonding portion 43 of the obtained optical package only has the third circuit board base metal layer 412C as a layer containing gold, and the thickness of the bonding portion 43 and the third circuit board base metal layer 412C. The volume ratio of gold to the bonding portion 43 calculated from the thickness was 0.87%.

In addition, in order to conduct the following reflow tests and heat cycle tests, seven optical packages were manufactured under the same conditions.
(Evaluation)
(1) Airtightness test without heat treatment For one optical package, the airtightness test described above was carried out after production, and it was judged as pass.
(2) Airtightness Test after Reflow Test Further, the following reflow tests 1 to 3 were conducted for the three optical packages.

As the reflow test 1, one optical package was placed in a reflow furnace and heated once with the temperature profile shown in FIG.

As the reflow test 2, one optical package was placed in a reflow furnace and heated three times repeatedly with the temperature profile shown in FIG.

As the reflow test 3, one optical package was placed in a reflow furnace and heated repeatedly five times with the temperature profile shown in FIG.

The air tightness test was carried out for each of the optical packages after the above reflow tests 1 to 3, and all optical packages passed.
(3) Airtightness test after heat cycle test For the three optical packages, the following heat cycle tests 1 to 3 were performed.

As heat cycle test 1, one optical package was subjected to 100 cycles of heat cycles of holding at -40.degree. C. for 30 minutes and then holding at 85.degree. C. for 30 minutes.

As heat cycle test 2, one optical package was subjected to 500 cycles of heat cycles of holding at −40 ° C. for 30 minutes and then holding at 85 ° C. for 30 minutes.

As heat cycle test 3, for one optical package, after holding for 30 minutes at -40.degree. C., 200 heat cycles for holding for 30 minutes at 100.degree. C. were performed.

The air tightness test was performed on each of the optical packages after the heat cycle tests 1 to 3 described above, and all optical packages passed.

According to the optical package of the present embodiment, since the proportion of gold occupied in the bonding portion is suppressed, the optical package can be reduced in cost.

Further, as described above, it was confirmed that high airtightness can be maintained not only immediately after the manufacture but also when the reflow test and the heat cycle test are performed. This is because the Young's modulus of the solder used for the solder layer of the window material is as low as 20 GPa, and the generation of the crack of the base 11 of the inorganic material and the peeling of the base 11 of the inorganic material and the circuit board 41 are not generated. Conceivable.
Example 2
(Window material)
According to the following procedure, the window material shown in FIG. 1 (A) and FIG. 1 (B) was produced and evaluated.

Also in the present example, as in the case of Example 1, a disc made of quartz was prepared as a material before cutting the base of the inorganic material (base preparation step).

Next, a bonding layer was formed on one surface of the pre-cutting material of the base of the inorganic material by the following procedure (bonding layer forming step).

A ground metal layer having a lattice pattern was formed on one surface of the base material of the inorganic material before cutting by ion beam deposition or electroless plating (ground metal layer forming step).

Specifically, first, a chromium (Cr) layer with a thickness of 0.2 μm as the first base metal layer 121A and a copper (Cu with a thickness of 0.2 μm as the second base metal layer 121B in this order from the inorganic material base 11 side. ) Layer was formed by ion beam evaporation.

Next, a 0.8 μm thick nickel-boron alloy (Ni-B) is formed as a third base metal layer by electroless nickel-boron alloy plating on the patterned first base metal layer and the second base metal layer. ) Layer was formed.

Next, in the same manner as in Example 1, the solder layer 122 was formed on the base metal layer 121. The same solder as in the first embodiment is used for the solder layer 122.

Then, in the same manner as in Example 1, the pre-cut material 51 (see FIG. 5) of the base of the inorganic material was cut and singulated. Thereby, the window material whose base of inorganic material is 5 mm square was obtained.

Since the obtained window material does not contain a layer containing gold, the volume ratio of gold in the bonding layer is zero. As shown in FIG. 2, the side surface of the inorganic material substrate after singulation had a linear pattern parallel to one surface 11 a and the other surface 11 b of the inorganic material substrate 11 as shown in FIG. 2. .

When the line width and length of one side of the solder layer 122 of the window material 10 were measured using an optical microscope (BX51TRF manufactured by Olympus), the line widths W1 to W4 were 0.3 mm, and the length L1 of one side of the opening L2 was 3.0 mm.

The line widths W1 to W4 and the lengths L1 and L2 of one side of the opening are measured and calculated in the same manner as in Example 1, and thus the description thereof is omitted here.

About the three window materials of sample 1 to sample 3 which were cut out from the material before cutting of the base of the same inorganic material using the laser microscope (type: VK-8510, manufactured by Keyence Corporation) for the thickness of the solder layer The eight measurement points Z1 to Z8 shown in FIG. And the weighted average value was calculated | required using the average value (simple average value) of the thickness of a solder layer about each sample using the obtained measured value, and Formula (1) as stated above. The results are shown in Table 1.

(Optical package)
The optical package shown in FIG. 4 was manufactured using the window material.

A 10 μm thick tungsten (W) layer is used as the first circuit board base metal layer 412A, and a 3 μm thick nickel (Ni) layer is used as the second circuit board base metal layer 412B. As the metal layer 412C, a gold (Au) layer having a thickness of 2 μm was formed.

The base metal layer for circuit board 412 has a shape corresponding to the bonding layer 12 of the window material 10. Specifically, the cross-sectional shape in a plane perpendicular to the stacking direction (vertical direction in FIG. 4) of the bonding layer 12 of the window material 10 and the base metal layer 412 for circuit board is the bonding layer 12 and the base for circuit board It was configured to have the same shape as the metal layer 412. Therefore, the base metal layer for circuit board 412 has an outer diameter of 3.6 mm square and a line width of 0.3 mm.

And along the block arrow B by the pressing means provided with a pressing member in contact with the base 11 of the inorganic material on the other surface 11b of the base 11 of the inorganic material of the window 10 and a spring applying pressure to the pressing member. was placed in the pressure heat treatment furnace while applying a (200 g) _{(N 2} atmosphere) Te. Then, with the temperature profile shown in FIG. 7, the window material 10 and the circuit board 41 are fusion bonded to form an optical package.

Specifically, the temperature was raised from 23 ° C. to 80 ° C., which is the first heat treatment temperature, and held for 300 seconds. Next, the temperature was raised to 280 ° C., which is the second heat treatment temperature, and held for 60 seconds, after which the heater was turned off and cooled to 23 ° C.

The bonding portion 43 of the obtained optical package only has the third circuit board base metal layer 412C as a layer containing gold, and the thickness of the bonding portion 43 and the third circuit board base metal layer 412C. The volume ratio of gold in the bonding portion 43 calculated from the thickness was 3.0% to 3.4%.
(Evaluation)
When the airtightness test was implemented about the obtained optical package, it was a pass.
[Example 3]
When joining the window material 10 and the circuit board 41, an optical package was produced in the same manner as in Example 2 except that the atmosphere in the heat treatment furnace was changed to an N ₂ atmosphere to make the atmosphere (air atmosphere).

When the airtightness test was implemented about the obtained optical package, it was a pass.
Example 4
When manufacturing the window material, after forming the solder layer 122, when separating into pieces, the window material and the optical package are manufactured in the same manner as in Example 2 except that the number of times of scanning of the laser light is made twice. did.

Specifically, at the time of the first irradiation of the laser light, the laser light is set along a planned cutting line by setting the position far from the laser light incident surface in the thickness direction of the material of the inorganic material before cutting. The irradiation position of was moved. When the second irradiation of the laser light is performed, the focal position of the laser light is changed to a position closer to the incident plane of the laser light than the first irradiation, and similarly, the irradiation position of the laser light along the planned cutting line Moved.

After the second irradiation of the laser beam, the material before cutting the substrate of the inorganic material was cut by applying a force such that the point where the focal position of the laser beam passed is the fulcrum.

As a result, as shown in FIG. 8, two

linear patterns

811 and 812 which are considered to be generated due to a change in the bonding state of the inorganic material are generated on the side surface of the individualized inorganic material base 11. Was confirmed. The two

linear patterns

811 and 812 have a shape along the outer periphery of one surface 11 a and the other surface 11 b.

In addition, also when the output of a laser was changed, it has also been confirmed that the pattern of the same shape is obtained on the cut surface.

Also in this case, the substrate 11 of the inorganic material can be separated into pieces without generating defects such as chipping, cracking, chipping and the like.

When the surface roughness of the

linear patterns

811 and 812 generated at this time is measured using a laser microscope (model: VK-8510, manufactured by KEYENCE CORPORATION), the surface roughness Ra is 0.3 μm, and linear The surface roughness Ra of the region 82 between the pattern 811 and the surface 11a was measured to be 1.1 μm. Also from the evaluation result of the surface roughness, it can be confirmed that the bonding state of the inorganic material is changed between the linear pattern 811 and the other portion.

An optical package was produced in the same manner as in Example 2 except that the obtained window material was used.

When the airtightness test was implemented about the obtained optical package, it was a pass.

Although the window material and the optical package have been described above in the embodiments and examples, the present invention is not limited to the above embodiments and examples. Various changes and modifications are possible within the scope of the present invention as set forth in the claims.

This application claims the priority of Japanese Patent Application No. 2017-122542 filed on Jun. 22, 2017 based on Japanese Patent Office, and the entire contents of Japanese Patent Application No. 2017-122542 I will use it.

DESCRIPTION OF SYMBOLS 10 Window material 11 Base of

inorganic material

111, 811, 812

Linear pattern

12, 52 Bonding layer 121 Base metal layer 122 Solder layer 40 Optical package 41 Circuit board 411 Insulating base 42 Optical element 43 Bonding part

Claims

A window material for an optical package provided with an optical element, comprising:
A substrate of inorganic material,
And a bonding layer disposed on one side of the substrate of the inorganic material,
The window material in which the volume ratio of gold in the bonding layer is 10% or less.
The bonding layer has a base metal layer and a solder layer,
The window material according to claim 1, wherein the average value of the thickness of the solder layer is 5 μm or more and 50 μm or less.
The window material according to claim 2, wherein the deviation of the thickness of the solder layer is ± 20 μm or less.
The window material according to claim 2 or 3, wherein the Young's modulus of the solder constituting the solder layer is 50 GPa or less.
The solder constituting the solder layer contains tin, germanium and nickel,
The content of germanium is 10% by mass or less,
The window material according to any one of claims 2 to 4, wherein the content of the germanium and the content of the nickel satisfy the following formula (1).
[Ni] ≦ 2.8 × [Ge] 0.3 (1)
(However, [Ni] indicates the content of nickel in mass% conversion, and [Ge] indicates the content of germanium in mass% conversion.)
The window material according to any one of claims 1 to 5, wherein the side surface of the inorganic material base has a linear pattern along the outer periphery of the one surface.
An optical package comprising the window material according to any one of claims 1 to 6 and a circuit board provided with an optical element.
The optical package according to claim 7, wherein the circuit board has a ceramic insulating base.
The base of the inorganic material of the window material and the insulating base of the circuit board are joined by a bonding portion,
9. The optical package according to claim 7, wherein the volume fraction of gold in the joint is 5% or less.