KR102656315B1 - Window material, optical package - Google Patents

Abstract

A window material for an optical package including an optical element, comprising: a base made of an inorganic material; and a bonding layer disposed on one side of the base made of an inorganic material along an outer periphery of the base made of the inorganic material, the bonding layer comprising: A window material having a width of 0.2 mm or more and 2 mm or less, and a thickness of the bonding layer greater than 15 μm and less than or equal to 100 μm is provided.

Description

Window material, optical package

The present invention relates to window materials and optical packages.

Conventionally, after placing an optical element such as a light-emitting diode in a recessed portion of a circuit board, the opening of the recessed portion was sealed with a window member provided with a transparent resin base material, etc., and used as an optical package.

In this case, the window material was bonded to the circuit board with a resin adhesive or the like, but improvement in airtight sealing properties was required depending on the type of optical element, etc. For this reason, it has been studied to join the circuit board and the window member using a metal material instead of a resin adhesive.

For example, Patent Document 1 discloses a mounting substrate, an ultraviolet light-emitting element mounted on the mounting substrate, a spacer disposed on the mounting substrate and having a through hole exposing the ultraviolet light-emitting element, and the through hole of the spacer. A cover is provided on the spacer to block the ultraviolet ray light-emitting element, the ultraviolet ray light-emitting element has an emission peak wavelength in the ultraviolet ray wavelength range, and the mounting substrate is provided with a support body and a first bonding metal layer supported on the support body, and The spacer faces the first bonding metal layer of the mounting substrate on the side of the spacer body formed of Si and the mounting substrate in the spacer body, and covers the entire circumference of the outer peripheral edge of the opposing surface. It has a second bonding metal layer formed along the surface, the through hole is formed in the spacer body, the opening area of the through hole gradually increases as it moves away from the mounting substrate, and the cover emits ultraviolet light. It is formed of glass that transmits ultraviolet rays emitted from the device, 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 are used for the second bonding. A light emitting device is disclosed, characterized in that the metal layer is bonded with AuSn over the entire circumference.

Japanese Patent Publication No. 5877487

In the light emitting device disclosed in Patent Document 1, the cover and the spacer are directly joined by anodic bonding, but there are cases where cracks occur in the cover after bonding.

In consideration of the problems with the prior art, one aspect of the present invention aims to provide a window member that suppresses the occurrence of cracks when bonded to a circuit board.

In order to solve the above problems, one aspect of the present invention is a window material for an optical package equipped with an optical element,

A gas of inorganic material,

On one side of the base made of the inorganic material, there is a bonding layer disposed along the outer periphery of the base made of the inorganic material,

The width of the bonding layer is 0.2 mm or more and 2 mm or less,

A window material is provided in which the thickness of the bonding layer is greater than 15 ㎛ and less than 100 ㎛.

According to one aspect of the present invention, it is possible to provide a window member that suppresses the occurrence of cracks when bonded to a circuit board.

1 is an explanatory diagram of the configuration of a window material in this embodiment.
Fig. 2 is an explanatory diagram of an example of the configuration of the side surface of the body made of inorganic material.
3 is an explanatory diagram of the configuration of the optical package of the present embodiment.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments, and various modifications and substitutions may be made to the following embodiments without departing from the scope of the present invention. can be added.

[Changjae]

The invention of this embodiment will be described.

The window material of the present embodiment is a window material for an optical package provided with an optical element, and has an inorganic material base and a bonding layer disposed on one side of the inorganic material base along the outer periphery of the inorganic material base. You can. Additionally, the width of the bonding layer can be 0.2 mm or more and 2 mm or less, and the thickness of the bonding layer can be thicker than 15 μm and 100 μm or less.

A structural example of the window member of the present embodiment will be described in detail below using Figs. 1(A) and 1(B). FIG. 1(A) schematically shows a cross-sectional view in a plane parallel to the lamination direction of the inorganic material base 11 and the bonding layer 12 of the window member 10 of the present embodiment. Additionally, FIG. 1(B) shows the structure when the window member 10 shown in FIG. 1(A) is viewed along the block arrow A shown in FIG. 1(A). That is, a bottom view of the window member 10 shown in FIG. 1(A) is shown.

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

Here, one side 11a of the inorganic material base 11 corresponds to the side that is bonded to the circuit board provided with the optical element when manufacturing the optical package described later. In other words, one side 11a of the inorganic material base 11 can also be said to be the side facing the optical element.

In addition, the other surface 11b located on the opposite side to one surface 11a of the inorganic material base 11 becomes the surface exposed to the outside when used as an optical package.

Each member is explained below.

(gas of inorganic material)

The base 11 made of an inorganic material is not particularly limited, and can be made into any shape using any material.

However, when the base body 11 made of an inorganic material is used as an optical package, light in a wavelength range that is particularly required to be transmitted among the light related to the optical elements included in the circuit board (hereinafter referred to as “light in the desired wavelength range”) ), it is desirable to select the material, its thickness, etc. 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, even more preferably 80% or more, and especially preferably 90% or more.

The inorganic material base 11 preferably has a transmittance of 50% or more, for example, when the light in the desired wavelength range is light in the infrared range, for example, for light in the range of 0.7 μm to 1 mm, the transmittance is preferably 50% or more, and 70% or more. This is more preferable, 80% or more is more preferable, and 90% or more is especially preferable.

In addition, when the light in the desired wavelength region is light in the visible region (blue to green to red), for example, for light in the range of 380 nm to 800 nm, the transmittance of the inorganic material base 11 is 50% or more is preferable, 70% or more is more preferable, 80% or more is still more preferable, and 90% or more is especially preferable.

When the light in the desired wavelength region is light in the ultraviolet region, the base 11 made of an inorganic material preferably has a transmittance of 50% or more, for example, for light in the wavelength range of 200 nm to 380 nm, and is 70% or more. This is more preferable, 80% or more is more preferable, and 90% or more is especially preferable.

When the light in the desired wavelength range is UV-A light in the ultraviolet range, for example, for light in the range of 315 nm to 380 nm, the base 11 of inorganic material preferably has a transmittance of 50% or more. , 70% or more is more preferable, 80% or more is still more preferable, and 90% or more is particularly preferable.

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

When the light in the desired wavelength range is UV-C light in the ultraviolet range, for example, for light in the range of 200 nm to 280 nm, the base 11 of inorganic material preferably has a transmittance of 50% or more. , 70% or more is more preferable, 80% or more is still more preferable, and 90% or more is particularly preferable.

Additionally, the transmittance of the inorganic material gas 11 can be measured based on JIS K 7361-1 (1997).

The material of the inorganic base 11 can be selected arbitrarily as described above and is not particularly limited, but from the viewpoint of particularly improving hermetic sealing properties and durability, for example, quartz, glass, etc. are preferable. It can be used easily. Quartz includes quartz glass and those containing 90% by mass or more of SiO ₂ . Examples of glass include soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, crystallized glass, and high refractive index glass (nd ≥ 1.5). Additionally, the material for the inorganic base is not limited to one type, and two or more types of materials may be used in combination. Therefore, for example, the material of the inorganic material base 11 includes, for example, quartz, soda lime glass, aluminosilicate glass, borosilicate glass, alkali-free glass, crystallized glass, and high refractive index glass (nd ≥ 1.5). One or more types of materials selected from can be preferably used.

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

The thickness of the inorganic material base 11 is not particularly limited, but for example, it is preferably 0.03 mm or more, more preferably 0.05 mm or more, even more preferably 0.1 mm or more, and 0.3 mm or more. It is particularly preferable to set it to mm or more.

By setting the thickness of the inorganic material base 11 to 0.03 mm or more, the strength required for the optical package is sufficiently exhibited, while preventing moisture, etc. from passing through the surface of the inorganic material base 11 of the window member to the side where the optical element is placed. Penetration can be particularly suppressed. As described above, it is preferable to set the thickness of the inorganic material base 11 to 0.3 mm or more because the strength of the optical package can be particularly increased.

The upper limit of the thickness of the inorganic material base 11 is not particularly limited, but for example, it 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 the desired wavelength range can be sufficiently high by setting the thickness of the inorganic material base 11 to 5 mm or less. It is more preferable to set the thickness of the inorganic material base 11 to 1 mm or less, especially because the optical package can be reduced in size.

In addition, in Fig. 1(A), an example of a plate-shaped (plate-shaped) base 11 of an inorganic material is shown, but it is not limited to this form. The shape of the base 11 of inorganic material is not particularly limited, and the thickness does not need to be uniform. For this reason, when the thickness of the inorganic material substrate is not uniform, it is preferable that the thickness of the portion of the inorganic material substrate that is on the optical path of the light related to the optical element at least in the case of an optical package is within the above range, and the inorganic material substrate is preferably in the above range. It is more preferable that the thickness of the material base is within the above range in all parts.

The shape of the body 11 made of inorganic material is not particularly limited as described above. For example, it can be a plate shape or a shape in which the lens is integrated, that is, a shape including concave portions or convex portions originating from the lens. Specifically, for example, one surface 11a of the base 11 made of an inorganic material is a flat surface and the other surface 11b has a convex portion or a concave portion, or the shape of one surface 11a The shape of the other surface 11b may be the reverse of this shape. In addition, one surface 11a of the base 11 made of an inorganic material has a convex part and the other surface 11b has a concave part, or the shape of one surface 11a and the other surface 11b are formed. The shape may be the reverse of this shape. Additionally, one surface 11a and the other surface 11b of the base body 11 made of an inorganic material may each have a convex portion or a concave portion.

In addition, even if one side 11a of the base body 11 made of an inorganic material has a convex portion or a concave portion, the portion on which the bonding layer 12 is disposed on one side 11a of the base body 11 made of an inorganic material is In order to suppress variation in the shape of the bonding layer 12 between window members, for example, when manufacturing a plurality of window members, it is preferable that it is flat.

Depending on the form of the optical package, the size of the inorganic material body may be very small. Therefore, when cutting the material to a desired size before cutting the base of the inorganic material, it is desirable to adopt a cutting method using laser light. Then, when cutting is performed by this method, as shown in FIG. 2, the side surface of the inorganic material body 11 is formed along a line along the outer periphery of one side 11a, corresponding to the focal position of the laser light. It may have the shape (111).

In addition, the cutting method of the inorganic material base 11 is not limited to the examples described above, and can be cut by any method. When cutting is performed by a method other than the cutting method described above, the side surface, or cut surface, of the base body 11 made of inorganic material may have a cross-sectional shape different from the case described above. Other cutting methods include, for example, a dicing saw or a wire saw. These cutting methods are effective when the thickness of the material before cutting the base of the inorganic material is 1 mm or more.

An antireflection film may be disposed on the surface of the base 11 made of an inorganic material. By disposing an anti-reflection film, in the case of an optical package, reflection of light from the optical element or the outside on the surface of the inorganic material base 11 can be suppressed, and the transmittance of the optical element or the light from the outside can be increased. It is desirable. The antireflection film is not particularly limited, but for example, a multilayer film can be used. The multilayer film is one selected from alumina (aluminum oxide, Al ₂ O ₃ ), hafnium oxide (HfO ₂ ), titanium oxide (TiO ₂ ), etc. It can be a film in which a first layer, which is a layer of more than one kind of material, and a second layer, which is a layer of silica (silicon oxide, SiO ₂ ), are alternately laminated. The number of layers constituting the multilayer film is not particularly limited, but for example, the first layer and the second layer are preferably set as one set, and the multilayer film preferably has at least one set of the first layer and the second layer, and 2 It is more preferable to have more than trillion. This is because reflection of light from the surface of the base 11 made of an inorganic material can be particularly suppressed by the multilayer film having one or more sets of the first layer and the second layer.

The upper limit of the number of layers constituting the multilayer film is not particularly limited, but for example, from the viewpoint of productivity, etc., it is preferable to have 4 or less sets of the first layer and the second layer.

When having an anti-reflection film, the anti-reflection film is preferably disposed on at least one side 11a of the base 11 made of an inorganic material, and is disposed on both sides of one side 11a and the other side 11b. It is more preferable. When arranging anti-reflection films on both surfaces of one side 11a and the other side 11b, the compositions of both anti-reflection films may be different, but from the viewpoint of productivity and the like, it is preferable to have anti-reflection films of the same structure.

When using the above-mentioned multilayer film as an anti-reflection film, it is preferable that the second layer of silica is located on the outermost surface. This is desirable because the second layer of silica is located on the outermost surface of the antireflection film, so that the surface of the antireflection film has a composition similar to that of the glass substrate, and durability and adhesion to the bonding layer 12 are particularly improved.

(bonding layer)

The bonding layer 12 corresponds to a member that bonds the inorganic material base 11 and the circuit board provided with the optical element in the case of an optical package.

The shape of the bonding layer 12 is not particularly limited, but, for example, as shown in FIG. 1(B), it is a view of the window member 10 when viewed from the side on which the bonding layer 12 is formed, that is, a bottom view. In this case, the bonding layer 12 including the solder layer 122 may be arranged along the outer periphery of the base body 11 made of an inorganic material. That is, the bonding layer 12 may have a strip-like shape disposed along the outer periphery of the base 11 made of an inorganic material, for example. The bonding layer 12 can have an opening in the center corresponding to the optical element of the circuit board, and the body 11 of the inorganic material is visible from the opening. In Fig. 1(B), the base 11 made of an inorganic material is larger than the bonding layer 12 including the solder layer 122, but it is not limited to this form. For example, the outer circumference of the base body 11 made of an inorganic material may be configured to coincide with the outer circumference of the bonding layer 12 including the solder layer 122.

In addition, in Fig. 1(B), the solder layer 122 located on the outermost surface of the bonding layer 12 is shown, but the stacking direction of each layer of the bonding layer 12 (up and down in Fig. 1(A)) is shown. It is preferable that the cross-sectional shape of the bonding layer 12 in the plane perpendicular to the direction is the same regardless of the layer.

According to the examination by the inventors of the present invention, the width (line width) (W) of the related bonding layer 12 is set to be 0.2 mm or more and 2 mm or less, and the thickness (T) of the bonding layer 12 is set to be less than 15 μm. It is desirable to be thick and less than 100 ㎛.

In addition, the width W of the bonding layer 12 refers to the bonding layer having a strip-like shape when viewed from the upper or lower surface of the inorganic material base 11, as shown in FIG. 1(B). (12) refers to the width of . That is, the width (W) of the bonding layer 12 is the distance between the outer circumferential side 12A and the inner circumferential side 12B, measured along a line segment drawn perpendicular to the inner circumferential side 12B of the bonding layer 12. it means. In addition, the thickness T of the bonding layer 12 refers to the lamination direction (up and down direction in FIG. 1(A)) of the bonding layer 12, the inorganic material base 11, and the bonding layer 12. It means thickness. For example, as shown in FIG. 1(A), when the inorganic material base 11 has a plate shape, this thickness T is perpendicular to one side 11a of the inorganic material base 11. It means the thickness of the bonding layer 12 measured along the line segment.

The width (W) and thickness (T) of the bonding layer 12 preferably satisfy the above range when measured at an arbitrary position with respect to the bonding layer 12. That is, it is desirable that the above range is satisfied no matter where the measurement is made at any location in the bonding layer 12.

As will be described later, the bonding layer 12 may have a base metal layer 121 or a solder layer 122. For example, when forming the solder layer 122, the bonding layer 12 or the inorganic There are cases where the material gas 11 is heated and cooled. The inorganic material base 11 and the bonding layer 12 are made of different materials, and there are differences in the degree of expansion and contraction during heating and cooling. For this reason, when the bonding layer 12 is formed, residual stress may occur at the interface between the inorganic material base 11 and the bonding layer 12. And, according to the examination by the inventors of the present invention, it is presumed that this residual stress causes cracks to form in the window member when a circuit board including a window member and an optical element is joined.

Therefore, in the window member 10 of the present embodiment, the generation of the residual stress is suppressed by keeping the width W and thickness T of the bonding layer 12 within a predetermined range as described above.

Specifically, by setting the width W of the bonding layer 12 to 2 mm or less, the interface between the inorganic material base 11 and the bonding layer 12 can be reduced, thereby suppressing the generation of residual stress, When bonded to a circuit board provided with an optical element, cracks can be suppressed in the window member 10, specifically, in the base body 11 made of an inorganic material. The width W of the bonding layer 12 is preferably 0.6 mm or less, and more preferably 0.4 mm or less.

However, if the width W of the bonding layer 12 is excessively narrow, there is a risk that the bonding strength between the window member and the circuit board provided with the optical element may decrease, so the width W of the bonding layer 12 is It is preferable that it is 0.2 mm or more, and it is more preferable that it is 0.25 mm or more.

In addition, by setting the thickness T of the bonding layer 12 to 100 μm or less, the amount of deformation of the bonding layer 12 during formation of the bonding layer 12 is suppressed, and the base of the inorganic material ( 11) The applied force can be suppressed. For this reason, it is possible to suppress residual stress from occurring at the interface between the inorganic material base 11 and the bonding layer, and when bonded to a circuit board provided with an optical element, the window member 10, specifically the inorganic material base, can be suppressed. (11) This is desirable because it can suppress the occurrence of cracks. The thickness T of the bonding layer 12 is more preferably 50 μm or less, and even more preferably 30 μm or less.

However, if the thickness T of the bonding layer 12 is excessively thin, when bonding with a circuit board equipped with an optical element, the unevenness of the bonding surface of the circuit board cannot be absorbed, thereby preventing bonding with the circuit board. There is a risk that the strength may decrease or a gap may form at the junction with the circuit board, thereby reducing airtightness. For this reason, as described above, the thickness T of the bonding layer 12 is preferably thicker than 15 μm.

In addition, the distance D between the outer peripheral side surface 11a of the inorganic material base 11 and the outer peripheral side surface 12A of the bonding layer 12 is not particularly limited, but the outer peripheral edge of the bonding layer after application of the bonding layer In order to reduce the residual stress generated, it is preferably 0.5 mm or less, more preferably 0.3 mm or less, and even more preferably 0.1 mm or less.

The lower limit of the distance D between the outer peripheral side 11a of the inorganic material base 11 and the outer peripheral side 12A of the bonding layer 12 is not particularly limited. As described above, since the outer circumference of the base body 11 of the inorganic material may be configured to coincide with the outer circumference of the bonding layer 12 including the solder layer 122, for example, this distance D is 0. You can do more than this.

In addition, the distance D between the outer peripheral side surface 11a of the inorganic material base 11 and the outer peripheral side surface 12A of the bonding layer 12 is, for example, the bottom surface as shown in FIG. 1(B). In the figure, the outer peripheral side 11a of the inorganic material base 11, and the outer peripheral side 12A of the bonding layer 12 disposed along the outer peripheral side 11a of the inorganic material base 11, and It means the distance between . That is, in the bottom view as shown in FIG. 1(B), when a straight line is drawn perpendicular to the outer circumferential side 11a of the inorganic material body 11, the outer circumference of the inorganic material body 11 is on that straight line. It means the shortest distance between the side surface and the outer peripheral side surface (12A) of the bonding layer (12).

And, the distance D between the outer peripheral side 11a of the inorganic material base 11 and the outer peripheral side 12A of the bonding layer 12 is the outer peripheral side 11a of the inorganic material base 11. It is preferable that the above range is satisfied when measured at an arbitrary position with respect to the outer peripheral side surface 12A of the bonding layer 12 at a corresponding position. In other words, the outer peripheral side surface 11a of the base body 11 made of inorganic material and the outer peripheral side surface 12A of the bonding layer 12 at the corresponding position satisfy the above range no matter where the measurement is made. It is desirable.

The bonding layer 12 can be any member that can bond the inorganic material base 11 and the circuit board provided with the optical element, and there are no particular limitations on the materials constituting the bonding layer 12. However, for example, it is desirable to select the material or shape of the bonding layer so that the parameter (Z) calculated by the following equation (1) is 130 or less, and to select the material or shape of the bonding layer so that it is 100 or less. It is more preferable.

In addition, x0, x1, x2, x3, x4, and x5 in the above formula (1) respectively represent the following parameters.

x0: Young's modulus of the gas of inorganic material (MPa)

x1: Thermal expansion coefficient of the inorganic material gas at 20 ℃ or higher and 200 ℃ or lower (ppm/℃)

x2: Young’s modulus of bonding layer (MPa)

x3: Thermal expansion coefficient of the bonding layer at 20 ℃ or higher and 200 ℃ or lower (ppm/℃)

x4: average height of bonding layer (mm)

x5: Width of bonding layer (mm)

In addition, “x4: average height of the bonding layer” means the average value of the height when the height of the bonding layer is measured at any 5 or more points and 8 or less points. Also, regarding “x5: width of bonding layer”, if it is not uniform within the window material, the average value can be taken when the width is measured at any 4 or more points and 12 or less points.

Young's modulus can be calculated from the results of tests based on JISZ2241 (2011) “Tensile test method for metallic materials” or JISR1602 (1995) “Elastic modulus test method for fine ceramics”. In addition, the thermal expansion coefficient is calculated by JISZ2285 (2003) "Method for measuring linear expansion coefficient of metallic materials" or JISR3102 (1995) "Testing method for average linear expansion coefficient of glass".

It is preferable to set the above-mentioned parameter (Z) to 130 or less because it is possible to particularly suppress cracks in the window member 10, specifically, the base 11 made of an inorganic material when bonded to a circuit board. Additionally, the lower limit of the parameter (Z) is not particularly limited, but is preferably set to 10 or more.

The bonding layer 12 may be any member capable of bonding the inorganic material base 11 and the circuit board provided with the optical element, and the configuration of the specific layer is not particularly limited. However, from the viewpoint of improving airtightness when used as an optical package, the bonding layer 12 is preferably made of a metal material, and the bonding layer 12 is, for example, as shown in FIG. 1(A). It is desirable to have an underlying metal layer 121 and a solder layer 122.

Hereinafter, a configuration example of each layer of the bonding layer 12 will be described.

First, the underlying metal layer 121 will be described.

The base metal layer 121 can have a function of increasing the adhesion between the base 11 made of an inorganic material 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 or three layers. Specifically, for example, it may have a first base metal layer 121A and a second base metal layer 121B in that order from the base 11 side of the inorganic material. Additionally, a third base metal layer 121C may be further disposed between the second base metal layer 121B and the solder layer 122.

The first base metal layer 121A can have a function of increasing the adhesion between the inorganic material base 11 and other layers. The material of the first base metal layer 121A is preferably a material that can increase the adhesion between the inorganic material base 11 and other layers, and a material that can also increase airtightness is more preferable. The first base metal layer 121A is preferably a layer containing one or more types selected from, for example, chromium (Cr), titanium (Ti), tungsten (W), and palladium (Pd). The first base metal layer 121A may be, for example, a layer made of one or more materials selected from chromium (Cr), titanium (Ti), tungsten (W), and palladium (Pd). Also, in this case, it is not excluded that the first base metal layer 121A contains unavoidable impurities.

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

The second base metal layer 121B has a function of increasing the adhesion between the solder layer and other layers, and includes, for example, one or more types selected from nickel (Ni), copper (Cu), platinum (Pt), and silver (Ag). It is preferable to use a layer containing metal. From the viewpoint of particularly reducing costs, it is more preferable that the second base metal layer 121B be a layer containing one or more types of metal selected from nickel (Ni) and copper (Cu).

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

In addition, when forming the third base metal layer 121C, it is preferable that the third base metal layer 121C be a layer containing one or more types selected from, for example, nickel (Ni) and gold (Au). do. In particular, when the third base metal layer 121C is a layer containing nickel (Ni), a layer containing nickel-boron alloy (Ni-B) or a layer made of Ni-B is used to improve solder wettability. It is desirable to do so. By forming the third base metal layer 121C, it is possible to particularly suppress, for example, a reaction between the base metal layer 121 and the solder layer 122. The third base metal layer may be a layer made of one or more types of metal selected from nickel (Ni) and gold (Au). Even in this case, it is not excluded 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 selected arbitrarily.

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

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

When the third base metal layer 121C is also formed, its thickness is not particularly limited, but is preferably set to, for example, 0.05 μm or more from the viewpoint of particularly suppressing the reaction between the base metal layer 121 and the solder layer 122. do. The upper limit of the thickness of the third base metal layer is not particularly limited, but is preferably 1.0 μm or less from the viewpoint of sufficiently reducing costs.

Next, the solder layer 122 will be described.

The solder layer 122 has a function of joining the inorganic material base 11 and the circuit board provided with the optical element when manufacturing an optical package, and its structure is not particularly limited. The solder layer 122 may contain solder as described below, but the solder here refers to a solder that is melted by heating when bonding to a circuit board equipped with an optical element, and then solidified by cooling to form a bond to the circuit board. It refers to a metal material that can be bonded to. In particular, from the viewpoint of strong joining, solder is a material that forms an intermetallic compound and can join the material disposed on the joining surface of the circuit board provided with the optical element when the solder is heated above the melting temperature. It is desirable to be

The thickness of the solder layer 122 is not particularly limited, but is preferably 5 μm or more, and more preferably 15 μm or more. The insulating base of the circuit board can be formed of, for example, a ceramic material as will be described later. However, when manufactured from a ceramic material, it is usually cast, so the surface joining the window member 10 must be completely flat. It is often difficult to do so. Therefore, it is desirable to set the thickness of the solder layer to 5 μm or more and to configure it so that it can absorb the unevenness of the surface joined to the window member 10 of the insulating base.

In addition, the thickness of the solder layer 122 referred to here means the thickness of the solder layer 122 at an arbitrary position of the window member 10 of the present embodiment. Therefore, it is desirable for the solder layer to meet this thickness range even in the thinnest part.

The upper limit of the thickness of the solder layer is not particularly limited, but can be, for example, 50 μm or less.

Additionally, the average thickness of the solder layer 122 is preferably 5 μm or more, and more preferably 15 μm or more. This means that by setting the average thickness of the solder layer 122 to 5 ㎛ or more, for example, even if the bonding surface with the bonding layer 12 of the circuit board to be bonded contains irregularities, the concave portion is not absorbed into the material of the solder layer. This is because the airtight sealing property can be especially improved by filling.

Additionally, the average value refers to the value of a simple average (sometimes called an arithmetic average or an additive average). Hereinafter, simply referring to “average” means simple average.

Also, the upper limit of the average thickness of the solder layer 122 is not particularly limited, but is preferably 50 μm or less, and more preferably 30 μm or less. This is because even if the average thickness of the solder layer 122 exceeds 50 μm and becomes excessively thick, there is no significant change in the effect of the airtight sealing property.

In addition, the average value of the thickness of the solder layer 122 can be calculated by measuring the thickness at a plurality of measurement points on the solder layer 122 with a laser microscope (manufactured by Keyence, model VK-8510) and calculating the average value. You can. The number of measurement points for measuring the thickness of the solder layer 122 to calculate the average value is not particularly limited, but for example, 2 or more points are preferable, and 4 or more points are more preferable. There is no particular limitation on the upper limit of the number of measurement points, but from the viewpoint of efficiency, 10 points or less is preferable, and 8 points or less is more preferable.

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

This is because it is desirable to keep the variation in the thickness of the solder layer 122 within ±20 μm, as it is possible to particularly improve the airtight sealing property between the window member and the circuit board on which the optical element is placed when manufacturing an optical package.

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

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

The solder layer 122 may contain various solders (compositions for joining) and may be made of various solders.

The solder contained in the solder layer 122 is not particularly limited, but for example, a material with a Young's modulus of 50 GPa or less is preferable, a material with a Young's modulus of 40 GPa or less is more preferable, and a material with a Young's modulus of 30 GPa or less is still more preferable.

After forming an optical package, for example, when the optical element emits light or turns off the light, a temperature change may occur in the solder layer. In addition, by setting the Young's modulus of the solder contained in the solder layer to 50 GPa or less, destruction of other members such as the inorganic material base 11 is particularly suppressed even when the solder layer portion expands or contracts due to temperature changes. Because it is possible and desirable.

Additionally, when the Young's modulus of the solder is 50 GPa or less, when forming an optical package, the stress generated by the difference in thermal expansion between the inorganic material base 11 and the circuit board provided with the optical element is applied to the solder layer joining the two members. This is desirable because it can be absorbed within (122).

The lower limit of the preferred range of Young's modulus of the solder contained in the solder layer 122 is not particularly limited, but for example, it may be greater than 0, and from the viewpoint of improving hermetic sealing properties, 10 GPa or more is preferable.

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

Additionally, the melting point of the solder contained in the solder layer 122 is preferably 200°C or higher, and more preferably 230°C or higher. This is because when the melting point of the solder is 200°C or higher, the heat resistance when used as an optical package can be sufficiently increased. However, the melting point of the solder used for the solder layer 122 is preferably 280°C or lower. This means that when manufacturing an optical package, heat treatment is performed to melt at least part of the solder layer 122. When the melting point of the solder is 280°C or lower, the temperature of the heat treatment can be kept low, preventing damage to optical elements, etc. This is because the occurrence can be particularly suppressed. In addition, by suppressing the heat treatment temperature low, the difference in the degree of shrinkage resulting from the difference in thermal expansion coefficient between the material of the inorganic base 11 and the insulating material of the circuit board can be reduced.

The solder contained in the solder layer 122 preferably has a density of 6.0 g/cm3 or more, and more preferably 7.0 g/cm3 or more. This is because by setting the density of the solder used for the solder layer 122 to 6.0 g/cm3 or more, the airtight sealing property can be particularly improved. The upper limit of the density of the solder used in the solder layer 122 is not particularly limited, but is preferably 10 g/cm3 or less, for example.

In addition, the thermal expansion coefficient of the solder contained in the solder layer 122 preferably has a predetermined relationship with the thermal expansion coefficient of the inorganic material base 11. Specifically, it is preferable that the difference between the thermal expansion coefficient of the inorganic material base and the thermal expansion coefficient of the solder contained in the solder layer is small. More specifically, it is preferable that the difference between the thermal expansion coefficient of the inorganic material base 11 and the thermal expansion coefficient of the solder contained in the solder layer 122 at 20°C or more and 200°C or less is 30 ppm/°C or less, It is more preferable that it is 10 ppm/℃ or less.

This means that when the difference between the thermal expansion coefficient of the inorganic material base 11 and the thermal expansion coefficient of the solder contained in the solder layer is small, the residual stress occurring between the inorganic material base 11 and the bonding layer 12 can be suppressed. This is because the occurrence of cracks can be particularly suppressed when bonded to a circuit board. Additionally, the difference between the thermal expansion coefficient of the inorganic material base and the thermal expansion coefficient of the solder contained in the solder layer can be 0 or more.

The thermal expansion coefficient of the solder contained in the solder layer 122 is not particularly limited, but the thermal expansion coefficient is preferably 30 ppm/°C or lower, and more preferably 25 ppm/°C or lower. This is because, when the thermal expansion coefficient of the solder is 30 ppm/°C or less, shape changes due to heat that occur when an optical element emits light in an optical package are suppressed, and damage to the optical package can be more reliably prevented. The lower limit of the thermal expansion coefficient of the solder contained in the solder layer 122 is not particularly limited, but is preferably 0.5 ppm/°C or more, for example.

The solder that can be preferably used in the solder layer 122 is not particularly limited and includes, for example, tin (Sn) - germanium (Ge) - nickel (Ni) solder or tin (Sn) - antimony. One or more types selected from the group consisting of (Sb)-based solder, gold (Au)-tin (Sn)-based solder, and tin (Sn)-silver (Ag)-copper (Cu)-based solder.

Additionally, for example, in the case of a tin-germanium-nickel solder, it may contain tin as a main component. Containing tin as a main component means, for example, that it is the component contained in the largest amount in solder, and it is preferable that tin is contained in 60% by mass or more in solder. For example, the tin content of this solder is more preferably 85.9% by mass or more, more preferably 87.0% by mass or more, and especially preferably 88.0% by mass or more.

This is because, when the tin content in the solder is 85.9% by mass or more, it exhibits a particularly high effect on alleviating the difference in thermal expansion between the member to be joined and the solder and lowering the melting temperature of the solder.

The upper limit of the tin content in the solder is not particularly limited, but for example, 99.9 mass% or less is preferable, 99.5 mass% or less is more preferable, and 99.3 mass% or less is still more preferable. Additionally, the tin-germanium-nickel solder may further contain one or more components selected from iridium, zinc, etc. in addition to tin, germanium, and nickel.

The content of each component of the tin-antimony solder is not particularly limited, but for example, it is preferable that the antimony content is 1% by mass or more. This is because antimony has the effect of increasing the solidus temperature in tin-antimony-based solders, and setting the antimony content to 1% by mass or more is preferable because this effect can be particularly exhibited.

The upper limit of the antimony content is not particularly limited, but is preferably set to 40% by mass or less, for example. This is because by setting the antimony content to 40% by mass or less, the solidus temperature can be prevented from becoming excessively high, and the solder can be made suitable for mounting electronic components.

Tin - Antimony-based solders may contain tin. Tin can alleviate the difference in thermal expansion between solder and members to be joined, such as a circuit board or base metal layer. Additionally, by containing tin as the 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.

Tin-antimony-based solder may be composed of antimony and tin, and in this case, the remainder excluding antimony may be composed of tin.

Tin-antimony-based solder may contain arbitrary additive components in addition to antimony and tin, and may contain, for example, one or more types selected from silver (Ag), copper (Cu), etc. Silver and copper, like antimony, have the effect of raising the solidus temperature of the solder. In this case, the remainder other than antimony and any added components can be comprised of tin.

Although structural examples of solder that can be preferably used in the solder layer 122 have been described, as described above, the solder used in the solder layer 122 is not limited to these solders.

In the window member 10 of the present embodiment, the residual stress at the interface between the inorganic material base 11 and the bonding layer 12 is preferably 100 MPa or less, and more preferably 50 MPa or less.

This means that by setting the residual stress at the interface between the inorganic material base 11 and the bonding layer 12 to 100 MPa or less, the residual stress occurring between the inorganic material base 11 and the bonding layer 12 is sufficiently maintained. This is because it is small and can particularly suppress the occurrence of cracks etc. when bonded to a circuit board.

Since it is desirable for the residual stress at the interface between the inorganic material base 11 and the bonding layer 12 to be small, its lower limit can be set to, for example, 0. However, since it is difficult to completely reduce the residual stress at the interface between the inorganic material base 11 and the bonding layer 12 to zero, this residual stress is preferably 10 MPa or more.

The window member of this embodiment has been described above, but in the window member of this embodiment, the bonding layer has a predetermined size. For this reason, the residual stress at the interface between the inorganic material base and the bonding layer can be suppressed, and the occurrence of cracks in the window material, specifically the inorganic material base, when bonded to the circuit board can be suppressed.

The manufacturing method of the window member of this embodiment is not particularly limited, but may include, for example, the following processes.

A gas preparation process that prepares gases from inorganic materials.

A bonding layer forming process of forming a bonding layer on one side of a base made of an inorganic material.

The specific operation of the base preparation process is not particularly limited, but for example, the base made of an inorganic material can be cut to a desired size or the shape of the base made of an inorganic material can be processed to have a desired shape. Additionally, when an anti-reflection film is disposed on the surface of a base made of an inorganic material, the anti-reflection film can also be formed in this process. The method of forming the anti-reflective film is not particularly limited, and for example, the film can be formed by a dry method or a wet method. In the case of a dry method, the film can be formed by one or more methods selected from vapor deposition, sputtering, ion plating, etc. there is. In the case of a wet method, the film can be formed by one or more methods selected from the immersion method, spray application method, etc.

The bonding layer forming process may include, for example, a base metal layer forming step and a solder layer forming step for forming the base metal layer.

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

Additionally, as described above, the base metal layer may be composed of multiple layers, and each layer may be formed into a film by an arbitrary method.

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

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

In the application method using a dispenser, for example, molten solder is supplied from a dispenser connected to a syringe to the member forming the solder layer, for example, the portion forming the solder layer of the base of the inorganic material on which the underlying metal layer is disposed. , 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 member forming a solder layer, for example, a portion forming a solder layer of an inorganic material base on which an underlying metal layer is disposed. Additionally, heat treatment may be performed after printing as needed.

In the laser metal deposition method, powdered solder is supplied to a member forming a solder layer, for example, a portion forming a solder layer of an inorganic material base on which an underlying metal layer is disposed, the solder is melted by a laser, and then cooled. This is a method of forming a solder layer by

The method using a solder wire uses solder processed into a wire shape, that is, a line shape, and solders a member forming a solder layer, for example, a base made of an inorganic material on which a base metal layer is disposed, for example by an automatic soldering robot. This is a method of forming a solder layer by supplying molten solder to the part where the layer is to be formed.

The method of manufacturing the window member of this embodiment may have additional arbitrary steps as needed.

The bonding layer can be formed into a desired shape on one side 11a of the base 11 made of an inorganic material, as explained using FIGS. 1(A) and 1(B).

For this reason, the manufacturing method of the window member of the present embodiment has, for example, a patterning step for forming a bonding layer by the base metal layer forming step and the solder layer forming step and then patterning the bonding layer to have a desired shape. It may be possible. In the patterning step, for example, a resist corresponding to the pattern to be formed is placed on the exposed surface of the solder layer, and the portion of the solder layer and the underlying metal layer not covered by the resist is removed by etching or the like to pattern the pattern. You can. A resist removal step to remove resist may be performed after the patterning step.

Additionally, in the case where the base metal layer includes a plurality of layers, a patterning step may be performed after forming a part of the layer included in the base metal layer, and a part of the layer included in the formed base metal layer may be patterned. . Then, after the patterning step, a resist removal step for removing the resist may be performed, and then the remaining base metal layer may be further formed on the patterned base metal layer.

Also, for example, the manufacturing method of the window material of this embodiment has a resist placement step of disposing a resist in a portion where the base metal layer and the solder layer are not formed before performing the base metal layer forming step and the solder layer forming step. It may be possible. 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 portions corresponding to the pattern to be formed. In this case, there may be a resist removal step to remove the resist after the solder layer formation step.

In addition, in order to manufacture multiple window members simultaneously, when multiple bonding layers corresponding to each window material are formed on a plurality of sizes of the inorganic material body (material before cutting), the inorganic material body is cut. You may also have a cutting process that does this. The cutting method is not particularly limited, and a cutting method tailored to the base of the inorganic material, such as the cutting method using laser light described above, can be adopted. Additionally, when the bonding layer is formed continuously in adjacent window members, that is, when the bonding layer is disposed on the cutting line, the bonding layer may also be cut in the cutting process.

Additionally, after forming an optical package, the inorganic material body and the like can be cut into individual pieces along with the circuit board.

[Optical package]

Next, a configuration example of the optical package of this embodiment will be described.

The optical package of this embodiment may have a circuit board provided with the window member and optical element described above.

A structural example of the optical package of this embodiment will be described using FIG. 3.

FIG. 3 schematically shows a cross-sectional view in a plane parallel to the stacking direction of the circuit board provided with the optical element and the window member of the optical package of the present embodiment. 3, the window member 10 and the circuit board 31 are described separately so that they can be distinguished, but in the optical package 30, both members are joined and integrated.

As described above, the optical package 30 of the present embodiment has a circuit board 31 provided with the window member 10 and the optical element 32 described above.

Since the window member 10 has already been described, the same numbers as in the case of FIG. 1 are assigned and the description is omitted.

There is no particular limitation on the circuit board 31, and various circuit boards provided with the insulating base 311 and wiring (not shown) for supplying power to the optical element 32 can be used.

However, when the window member 10 is joined, the circuit board 31 has an insulating base 311 made of ceramics in order to increase the airtight sealing property within the space surrounded by the window member 10 and the circuit board 31. desirable.

Here, the ceramic material used for the insulating base 311 of the circuit board 31 is not particularly limited, but examples include alumina (aluminum oxide, Al ₂ O ₃ ), aluminum nitride (AlN), and LTCC (Low Temperature). Co-fired Ceramics), etc. may be mentioned.

The shape of the insulating base 311 of the circuit board 31 is not particularly limited, but when used as the optical package 30, the optical package 311 is connected to the inorganic material base 11 and the insulating base 311 at a joint to be described later. It is preferable that the part where the element 32 is placed is configured to form a closed space. For this reason, it is desirable for the insulating substrate 311 to have an opening in the central portion of its upper surface 311a and to have a concave portion 311A that is a non-penetrating hole including the opening. In addition, the upper surface of the insulating base 311 is the surface that faces the window member 10 when used as an optical package, and can also be said to be the surface on the side that is joined to the window member 10.

The wall portion 311B surrounding this concave portion 311A is used to support the bonding layer 12 of the window member 10 and the base metal layer for a circuit board, which will be described later, together when used as an optical package. It may have a shape corresponding to the layer 12 or the base metal layer for a circuit board.

Additionally, the circuit board 31 may have a base metal layer 312 for a circuit board on the upper surface 311a of the insulating base 311 and the upper surface of the wall portion 311B.

The base metal layer 312 for a circuit board can have a function of increasing the adhesion between the insulating substrate 311 of the circuit board 31 and the window member 10. The specific configuration of the base metal layer 312 for the circuit board is not particularly limited, but for example, from the insulating base 311 side of the circuit board 31, the base metal layer 312A for the first circuit board, and the base metal layer 312A for the second circuit board. It may have a layer structure in which the base metal layer 312B and the third base metal layer for circuit board 312C are laminated in that order. In addition, although an example in which the base metal layer 312 for a circuit board is composed of three layers is shown here, it is not limited to this form and may be composed of one layer, two layers, or four or more layers.

As described above, when the base metal layer 312 for a circuit board is composed of three layers, for example, the first base metal layer 312A for a circuit board is used to form a wiring (circuit) in the circuit board 31. It is desirable to make it from the same metal as the metal used. For example, the base metal layer 312A for the first circuit board can be a layer containing one or more types of metal selected from copper (Cu), silver (Ag), and tungsten (W). The first base metal layer 312A for the circuit board may be a layer made of one or more types of metal selected from copper (Cu), silver (Ag), and tungsten (W). Also, in this case, it is not excluded that the base metal layer 312A for the first circuit board contains unavoidable impurities.

The second base metal layer 312B for a circuit board can be a layer that prevents alloying of the third base metal layer 312C for a circuit board, which will be described later, and the base metal layer 312A for a first circuit board, for example For example, it can be a layer containing nickel (Ni). The second base metal layer 312B for the circuit board may be a layer made of nickel (Ni). Also, in this case, it is not excluded that the base metal layer 312B for the second circuit board contains unavoidable impurities.

The third base metal layer 312C for a circuit board may be a layer to prevent the second base metal layer 312B for a circuit board from oxidation, and may be a layer containing gold (Au), for example. . The third base metal layer 312C for a circuit board may be a layer made of gold (Au). Also, in this case, it is not excluded that the third base metal layer 312C for a circuit board contains unavoidable impurities.

The thickness of each layer constituting the base metal layer 312 for a circuit board is not particularly limited and can be selected arbitrarily.

The thickness of the first base metal layer 312A for a circuit board is preferably 1 μm or more, for example. The upper limit of the thickness of the base metal layer 312A for the first circuit board is not particularly limited, but is preferably 20 μm or less from the viewpoint of sufficiently reducing costs.

The thickness of the second base metal layer 312B for the circuit board is preferably 1 μm or more from the viewpoint of particularly suppressing alloying of the first base metal layer 312A for the circuit board and the third base metal layer 312C for the circuit board. do. The upper limit of the thickness of the second base metal layer 312B for a circuit board is not particularly limited, but is preferably 20 μm or less from the viewpoint of sufficiently reducing costs.

The thickness of the third base metal layer for circuit boards 312C is preferably 0.03 μm or more from the viewpoint of particularly preventing oxidation of other base metal layers for circuit boards. The upper limit of the thickness of the third base metal layer 312C for a circuit board is not particularly limited, but is preferably 2.0 μm or less, and more preferably 0.5 μm or less from the viewpoint of sufficiently reducing costs.

The shape of the base metal layer 312 for a circuit board is not particularly limited, but in the case of the optical package 30, in order to form a joint portion 33 described later together with the bonding layer 12 of the window member 10, It is desirable to have a shape corresponding to the bonding layer 12 of the window member 10. Specifically, the bonding layer 12 of the window member 10 and the base metal layer 312 for a circuit board are formed on a plane perpendicular to the stacking direction (up and down direction in FIG. 3) of both members when forming an optical package. It is preferable that the cross-sectional shapes are the same.

The method of forming the base metal layer 312 for a circuit board is not particularly limited and can be arbitrarily selected depending on, for example, the type of base metal layer 312 for a circuit board to be formed. For example, the film can be formed by a dry method or a wet method, and in the case of a dry method, the film can be formed by one or more methods selected from vapor deposition, sputtering, ion plating, etc. In the case of a wet method, the film can be formed by one or more methods selected from electrolytic plating, electroless plating, printing, etc.

In addition, as described above, the base metal layer for a circuit board may be composed of multiple layers, and each layer may be formed into a film by an arbitrary method.

The optical element 32 disposed on the circuit board 31 is not particularly limited, and for example, a light-emitting element such as a light-emitting diode or a light-receiving element can be used.

Additionally, when the optical element 32 is a light-emitting element, the wavelength range of light emitted by the light-emitting element is not particularly limited. For this reason, for example, a light emitting element that emits light in an arbitrary wavelength range selected within the range from ultraviolet light to infrared light, that is, for example, light in an arbitrary wavelength range selected within the range of 200 nm to 1 mm, is used. You can use it.

However, according to the optical package of the present embodiment, the base of the window member, which is a member that transmits light from the light emitting element, is not a base of transparent resin, but a base 11 of an inorganic material. For this reason, compared to the case where a transparent resin base is used as the base of the window material, the airtight sealing property can be improved, and further, deterioration of the window material due to light from the light emitting element can be suppressed. For this reason, when the optical element is a light-emitting element, a light-emitting element that particularly requires airtightness, or a light-emitting element that emits light that is prone to resin deterioration is used, the optical package of this embodiment can be particularly effective. It is desirable. Examples of light-emitting elements that particularly require airtightness include light-emitting elements that emit UV-C, which is light in a wavelength range of 200 nm to 280 nm. In addition, light-emitting elements that emit light that are prone to resin deterioration include light-emitting elements that emit light with high output, such as a laser. Therefore, when the optical element 32 is a light-emitting element, a light-emitting element that emits UV-C, a laser, etc. can be preferably used as the light-emitting element, especially from the viewpoint of demonstrating high effectiveness.

And, the inorganic material base 11 of the window member 10 and the insulating base 311 of the circuit board 31 can be joined by the joint portion 33. As shown in FIG. 3 , the joint portion 33 may have a bonding layer 12 of the window member 10 and a circuit board base metal layer 312 of the circuit board 31. Additionally, the joint portion 33 may be composed of the joint layer 12 and the base metal layer 312 for a circuit board.

According to the optical package of the present embodiment described above, since the above-described window material is used, when the window material and the circuit board provided with the optical element are joined, cracks occur in the window material, specifically the base of the inorganic material. can be suppressed. For this reason, an optical package can be produced at high yield.

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 this embodiment may have, for example, the following processes.

A circuit board preparation process that prepares a circuit board with optical elements.

A joining process in which a window member is placed on a circuit board and the window member and the circuit board are joined.

In the circuit board preparation process, an optical element can be placed on a circuit board manufactured by a conventional method, thereby preparing a circuit board equipped with an optical element. In addition, when separating into individual pieces after completion of the bonding process, a circuit board in which a plurality of circuit boards are integrated before cutting can be prepared in the circuit board preparation process.

In addition, in the joining process, the window member can be placed on the circuit board, and the window member and the circuit board can be joined. The specific method of bonding is not particularly limited, but for example, first, in the optical package 30 shown in FIG. 3, the lower surface 12a exposed by the bonding layer 12 and the base metal layer 312 for a circuit board are The exposed upper surface 312a can be overlapped so that it is in direct contact. Then, for example, by pressing and heating from the other surface 11b of the inorganic material base 11 of the window member 10 toward the circuit board 31, that is, along the block arrow B in the figure, solder is formed. By melting at least part of the layer 122 and then cooling it, the window member 10 and the circuit board 31 can be joined.

In the joining process, the oxide film present on the surface of the lower surface 12a of the joining layer 12 melts into the inside of the solder layer 122 melted by heating, and forms the upper surface of the base metal layer 312 for a circuit board ( For 312a), it is preferable that the molten solder layer 122 is thin enough to be in contact with it. Although the specific thickness of the oxide film is not limited, the thickness of the oxide film is preferably 10 nm or less, and more preferably 5 nm or less.

In addition, the method of pressing the inorganic material base 11 is not particularly limited, and for example, may include a 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. Examples include a method of using a weight, a method of using a weight, etc.

In the optical package obtained after the bonding process, when a predetermined atmosphere is used in the area sealed by the window member 10 and the circuit board 31, the atmosphere when heat treatment is performed is set to the predetermined atmosphere. desirable. For example, an atmosphere selected from an atmospheric atmosphere, a vacuum atmosphere, an inert atmosphere, etc. can be used. The inert atmosphere can be an atmosphere containing one or more types of gas selected from nitrogen, helium, argon, etc.

In the joining process, the conditions for performing heat treatment are not particularly limited, and for example, it is preferable to heat to a temperature higher than the melting temperature of the solder in the solder layer. However, if heating is performed rapidly, thermal stress is applied to the base of the inorganic material, which may cause cracking, etc., so, for example, first, after raising the temperature to the first heat treatment temperature of 50 ℃ or more and less than the melting point of the solder of the solder layer, It is desirable to maintain the first heat treatment temperature for a certain period of time. The holding time at the first heat treatment temperature is not particularly limited, but for example, it is preferably 30 seconds or more, and more preferably 60 seconds or more. However, from the viewpoint of productivity, the holding time at the first heat treatment temperature is preferably 600 seconds or less.

After maintaining the first heat treatment temperature for a certain period of time, it is preferable to further increase the temperature to the second heat treatment temperature, which is a temperature higher than the melting point of the solder in the solder layer. In addition, the second heat treatment temperature is preferably higher than the melting point of the solder +20°C in order to sufficiently join the window member 10 and the circuit board 31, and if the second heat treatment temperature is excessively high, the Since the placed optical element may be damaged by heat, the second heat treatment temperature is preferably, for example, 300°C or lower. The time for maintaining the second heat treatment temperature is not particularly limited, but is preferably 20 seconds or more in order to sufficiently bond the window member 10 and the circuit board 31. However, in order to more reliably suppress the adverse effects of heat on the optical element, the time for maintaining the second heat treatment temperature is preferably 1 minute or less.

After 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 may have any process as needed. For example, when a circuit board in which a plurality of circuit boards are integrated and not separated into individual pieces is subjected to a bonding process, a cutting process may be performed. The cutting method used in the cutting process is not particularly limited, and cutting can be performed by any method. By using the cutting method using laser light described above in the description of the window member, the circuit board and the window member can be simultaneously cut and separated into individual pieces. Additionally, multiple cutting methods can be combined.

Example

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples. However, the present invention is not limited to these Examples, and the embodiments may be appropriately modified as long as the effect of the present invention is achieved.

First, the evaluation method of the optical package manufactured in the following examples and comparative examples will be described.

＜Evaluation method＞

[Crack evaluation]

For the optical packages manufactured in the following examples and comparative examples, the junction portion with the inorganic material base 11 was examined through the inorganic material base 11 using an optical microscope (SMZ900 manufactured by Nikon) at a magnification of 10 times. (33) An enlarged observation of the interface was performed, the gaseous (11) state of the inorganic material was confirmed, and cracking was evaluated under the following conditions.

○: There are no cracks or cracks at the contact portion of the inorganic material with the joint portion of the base body.

×: There are cracks or cracks on the contact surface of the inorganic material with the base body.

○ was considered passing.

[Confidentiality Evaluation]

The optical packages manufactured in the following examples and comparative examples were subjected to a helium leak test using a bombing method under the conditions described in JIS Z 2331 (2006), and airtightness was evaluated under the following conditions.

○: Helium leak rate is 4.9 × 10 ^-9 Pa·㎥/sec or less.

×: Helium leak rate is greater than 4.9 × 10 ^-9 Pa·㎥/sec

○ was considered passing.

[Example 1]

A window member and an optical package with the structure shown in FIG. 3 were manufactured, and the crack evaluation and airtightness evaluation were performed.

A quartz plate (manufactured by AGC, AQ, 8.5 mm long x 8.5 mm wide x 0.5 mm thick) was prepared as the inorganic material base 11 (base preparation step). Additionally, the quartz plate prepared as the inorganic material base 11 had a thermal expansion coefficient of 0.6 ppm/°C at 20°C or higher and 200°C or lower.

The bonding layer 12 was formed on one side 11a of the base 11 made of an inorganic material by the following procedure (bonding layer forming step).

A chromium (Cr) layer was formed as the first base metal layer 121A, and a copper (Cu) layer was formed as the second base metal layer 121B (base metal layer formation step).

Next, a resist is applied to the entire surface of the second base metal layer 121B on the side opposite to the surface facing the first base metal layer 121A, that is, the entire exposed surface, and then the resist is exposed using ultraviolet rays. , and further developed, to lay out the patterned resist. The patterned resist had a quadrangular shape in a cross section parallel to one side 11a of the base body 11 made of an inorganic material, and had a quadrangular opening in the center.

Then, the portions of the first base metal layer 121A and the second base metal layer 121B that were not covered by the resist were etched with an etching solution and patterned (patterning step). Afterwards, the resist was removed (resist removal step).

Next, a nickel (Ni) layer was deposited as a third base metal layer 121C on the patterned first base metal layer 121A and the second base metal layer 121B by electroless Ni plating. Thereby, the patterned base metal layer 121 containing the 1st base metal layer 121A, the 2nd base metal layer 121B, and the 3rd base metal layer 121C was formed. In addition, the thickness of the first base metal layer 121A was 0.2 μm, the thickness of the second base metal layer 121B was 0.6 μm, and the thickness of the third base metal layer 121C was 0.8 μm.

Next, the solder layer 122 was formed on the base metal layer 121 (solder layer formation step). The solder used for the solder layer 122 was prepared in advance according to the following procedure.

The components contained in the solder are weighed, mixed, and melted so that Sn is 97% by mass, Ge is 2% by mass, and Ni is 1% by mass, and a raw material alloy is produced. Then, this raw material alloy was melted and poured into a mold to produce solder.

As a result of calculating the Young's modulus of the obtained solder from the tensile test results, it was confirmed to be 20 GPa. Regarding the tensile test, a test piece of JIS14A was tested at a tensile speed of 3 mm/min using a tensile tester (Autograph AGX-100 kN manufactured by Shimadzu Corporation).

Additionally, the difference between the thermal expansion coefficient of the inorganic material base 11 and the thermal expansion coefficient of the solder used in the solder layer at 20°C or more and 200°C or less was 7.0 ppm/°C.

The solder serving as the raw material for the solder layer 122 is melted in a solder melting tank, and the portion forming the solder layer 122 of the inorganic material base 11 on which the above-described base metal layer 121 is disposed is, The solder layer 122 was formed by dipping into solder melted in a solder melting tank and then cooling (solder layer forming step). In addition, as shown in FIG. 3, the solder layer 122 was formed on the surface of the third base metal layer 121C opposite to the surface facing the second base metal layer 121B.

The solder layer 122 was formed so that the thickness T of the bonding layer 12 was 30 μm. Additionally, the bonding layer 12 obtained as above had a width W of 0.3 mm.

Next, a circuit board was prepared according to the following procedure (circuit board preparation process).

Additionally, an alumina (Al ₂ O ₃ ) base (8.5 mm long x 8.5 mm wide x 0.8 mm thick) was prepared as the insulating substrate 311 of the circuit board 31.

The central portion of the upper surface 311a of the insulating substrate 311 has a rectangular opening and a recess 311A, which is a non-penetrating hole, including the opening. The size of the concave portion 311A was 2.5 mm long x 2.5 mm wide x 0.4 mm deep. The optical element 32 can be placed in the concave portion 311A, but since the optical element is not required in the evaluation of this embodiment, the package was manufactured without installing it. However, it was confirmed that the same evaluation results were obtained even when optical elements such as light emitting diodes were placed.

Then, the circuit board 31 is formed on the upper surface 311a of the insulating base 311 so as to surround the opening of the concave portion 311A and along the outer periphery of the upper surface 311a of the insulating base 311. It has a base metal layer 312 for a substrate.

As the base metal layer 312 for a circuit board, from the insulating base 311 side, there is a base metal layer 312A for the first circuit board, a base metal layer 312B for the second circuit board, and a base metal layer 312C for the third circuit board. ) It was made into a layer structure stacked in the following order.

The first base metal layer 312A for the circuit board is a copper (Cu) layer with a thickness of 1.0 μm, the second base metal layer 312B for the circuit board is a nickel (Ni) layer with a thickness of 2 μm, and the third base metal layer 312A is a copper (Cu) layer with a thickness of 1.0 μm. As the base metal layer 312C for the circuit board, a gold (Au) layer with a thickness of 0.3 μm was formed.

The base metal layer 312 for a circuit board was shaped to correspond to the base metal layer 121 formed on the base 11 made of an inorganic material. Specifically, the cross-sectional shape in a plane perpendicular to the lamination direction (up and down direction in FIG. 3) of the bonding layer 12 formed on the base 11 of an inorganic material and the base metal layer 312 for a circuit board. This was configured so that the bonding layer 12 and the base metal layer 312 for a circuit board had the same shape (joining process).

The circuit board 31 and the window material 10 are brought into direct contact with the lower surface of the solder layer 122 of the bonding layer 12 formed on the base 11 of an inorganic material and the upper surface of the base metal layer 312 for a circuit board. was overlapped. Then, a weight is placed on the other side 11b of the base body 11 made of an inorganic material, a load of 90 gf is applied, and while pressing along the block arrow B in FIG. 3, it is heated at 280° C. for 1 minute in an atmospheric atmosphere. At least part of the solder layer 122 was melted and then cooled to join (joining process).

Through the above process, the window member and the circuit board 31 were bonded to produce an optical package.

The above-described evaluation was performed on the obtained optical package as a bonded product. The results are shown in Table 1.

[Example 2 to Example 5, Comparative Example 1 to Comparative Example 4]

In the bonding layer forming step, an experiment was conducted in the same manner as in Example 1, except that the width (W) and thickness (T) of the bonding layer 12 were set to the values shown in Table 1. The evaluation results are shown in Table 1.

According to the results shown in Table 1, in the optical package using the window materials of Examples 1 to 5 in which the width of the bonding layer is 0.2 mm or more and 2 mm or less and the thickness is thicker than 15 μm and 100 μm or less, crack evaluation, and It was confirmed that the result of the confidentiality evaluation was ○. In other words, it was confirmed that the window material and optical package suppressed cracks in the cover.

In contrast, in Comparative Examples 1 to 4 in which the width and thickness of the bonding layer did not meet the above requirements, it was confirmed that cracks occurred and airtightness was not sufficient.

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

This application claims priority based on Japanese Patent Application No. 2018-190370, filed with the Japan Patent Office on October 5, 2018, and the entire contents of Japanese Patent Application No. 2018-190370 are incorporated into this international application.

10: Changjae
11: Gas of inorganic material
12: bonding layer
122: solder layer
30: Optical package
31: circuit board
311: Insulating base material
32: optical element

Claims (6)

As a window material for an optical package equipped with an optical element,
A gas of inorganic material,
On one side of the base made of the inorganic material, there is a bonding layer disposed along the outer periphery of the base made of the inorganic material,
The width of the bonding layer is 0.2 mm or more and 2 mm or less,
The thickness of the bonding layer is thicker than 15 ㎛ and less than 100 ㎛,
The bonding layer has a solder layer,
The solder included in the solder layer is a tin-germanium-nickel solder,
A window material wherein the difference between the thermal expansion coefficient of the inorganic material base and the solder at 20°C or more and 200°C or less is 30 ppm/°C or less. According to claim 1,
A window material wherein the Young's modulus (E) of the solder included in the solder layer is 50 GPa or less. delete The method of claim 1 or 2,
A window material wherein the residual stress at the interface between the base of the inorganic material and the bonding layer is 100 MPa or less. An optical package comprising the window member according to claim 1 or 2 and a circuit board provided with an optical element. According to claim 5,
An optical package wherein the circuit board has an insulating substrate made of ceramics.

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