JP2003137592A - Translucent member and package for optical communication using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive translucent member having physical, thermal, electrical and optical properties suitable as an electronic member material, an optical material and a machine part material, and an inexpensive package for optical communication using this. SOLUTION: The translucent member 10 comprises a Ta-containing borosilicate glass and shows a refractive index within ±10% of that of sapphire and a flexural strength of >=130 MPa. The difference of coefficients of linear thermal expansion between the translucent member 10 and a metallic fixing member 31 brazed on this via a metallized layer 11 formed on the translucent member 10, is within ±5%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-transmissive member used in electronic component materials, optical materials, mechanical component materials and the like, and optical communication in which the inside of the member is kept airtight and the light of an optical fiber is transmitted. For packages.

[0002]

2. Description of the Related Art A transparent member that transmits light of an optical fiber for optical communication has high insulating properties, excellent light transmittance, good metallization, excellent mechanical strength, and wear resistance.
In addition to being used as electronic component materials, it has a wide range of application fields such as optical materials and mechanical component materials. A typical example of the translucent member is sapphire. There is an optical communication package for accommodating a semiconductor element for optical communication whose main body is made of ceramic or metal as a material using the transparent member made of sapphire as an electronic component material. As shown in FIGS. 5 and 6, for example, a metal optical communication package 70 includes a KV (Fe-Ni-Co based alloy, trade name "Kovar") or 42 alloy (Fe-Ni based alloy). ) Frame 71 made of metal such as
For mounting a semiconductor element for optical communication inside by brazing and joining to a bottom body 72 made of a metal such as Cu-W (copper tungsten) or Cu-Mo-Cu (copper molybdenum copper joint plate). It has a cavity 73. The optical communication package 70 has a through hole 74 formed on one side wall of the frame 71 and communicating with the cavity 73, and an insertion hole 75 for passing an optical signal through the cavity 73. A metal fixing member 76 made of a metal material is inserted and brazed and joined.

The optical communication package 70 includes a frame 7
In the window frame portion formed by cutting out on both side walls facing each other,
The feed through substrate 78 is provided with a conductor pattern 77 which is made of a ceramic material such as alumina (Al ₂ O ₃ ) and is formed so as to be conductive from the cavity portion 73 side of the frame body 71 to the outside of the frame body 71. Feedthrough board 78
In order to electrically connect the Ni-plated conductor pattern 77 on the outer portion of the frame body 71 from the outside,
An external connection terminal 79 made of V or 42 alloy or the like is brazed and joined to a butterfly type or the like. In addition, the optical communication package 70 has a seal ring 8 which is joined to the lid 82 on the upper end surface of the frame 71 to hermetically seal the cavity 73.
0 is brazed and joined.

The surface of the metal portion is plated with Ni and Au.
The plated optical communication package 70 is provided on the metal fixing member 76 in order to close the insertion hole 75 of the metal fixing member 76 to ensure airtightness inside the cavity 73 and to face the tip of the optical fiber. , Au-Sn wax,
Using a low temperature brazing material such as Au-Ge brazing material, a translucent member 8 made of sapphire via a thin metallized layer.
1 is brazed and joined. In the optical communication package 70 manufactured as described above, a semiconductor element is mounted in the cavity portion 73, and the semiconductor element and the conductor pattern 77 on the cavity portion 73 side of the feed-through substrate 78 are connected by a bonding wire or the like to make an external connection. The terminal 79 and the semiconductor element are brought into conduction. Further, the optical fiber member is fixed to the metal fixing member 7
6, after welding using a laser such as YAG, a lid 82 made of KV, 42 alloy or the like is joined to the upper surface of the seal ring 80 by seam welding or the like to form an optical semiconductor device. The device is screwed and fixed to a board or the like via the mounting hole 83.

[0005]

However, the above-mentioned conventional translucent member and the package for optical communication using the same have the following problems. (1) Sapphire is α-alumina (α-Al ₂ O
It is a single crystal body of ₃ ), and is suitable for electronic component materials, optical materials, mechanical component materials and decorations. In particular, physical properties such as transverse strength, hardness, Young's modulus, thermal properties such as melting point, thermal expansion coefficient, and thermal conductivity, electrical properties such as dielectric constant, dielectric strength, dielectric loss tangent, and refractive index, In terms of optical properties such as light transmittance, electronic component materials,
It is used as an optical material and a mechanical component material. However, since the cost is high, it is difficult to apply it to electronic component materials where low cost is an absolute requirement. In particular, it is difficult to apply sapphire because low cost is required for the translucent member used for the subscriber system package of the optical communication package. (2) Since sapphire has an unnecessarily high mechanical strength such as bending strength, it requires labor and cost to perform shape processing. The present invention has been made in view of such circumstances,
An inexpensive translucent member having physical properties, thermal properties, electrical properties, and optical properties suitable for electronic component materials, optical materials, and mechanical component materials, and inexpensive optical communication using the same The purpose is to provide a package for.

[0006]

Means for Solving the Problems A light-transmitting member according to the present invention which meets the above-mentioned object is a light-transmitting member made of borosilicate glass containing Ta and having a refractive index of ± of sapphire.
Having a refractive index of 10% or less and a bending strength of 130 MPa or more, the difference in the coefficient of linear thermal expansion from the metal fixing member that is brazed and joined via the metallized layer formed on the translucent member is ±.
Within 5%. As a result, since borosilicate glass, which is cheaper than sapphire but has a low refractive index, contains Ta to bring the refractive index close to that of sapphire, it is inexpensive and has optical properties and electrical characteristics comparable to sapphire. Can have specific properties. Further, borosilicate glass has a good yield because it can be processed into a desired shape by thermal processing, and while improving the bending strength of borosilicate glass by containing Ta, it is easy to grind and polish. Therefore, it can be processed at low cost and can have physical properties suitable for electronic component materials, optical materials, and mechanical component materials. Further, a translucent member that can easily adjust the thermal property with the metal fixing member to be joined can be provided by borosilicate glass containing Ta, which is cheaper than sapphire. If the difference between the refractive index of the translucent member and the refractive index of sapphire exceeds ± 10%, the traveling direction of light is greatly deviated, and correction thereof is not easy, so the function as a substitute for sapphire becomes low. Therefore, it is desired that the translucent member has a refractive index close to that of sapphire. Also,
If the transverse strength is less than 130 MPa, there is a risk of cracks in the translucent member in the extremely severe reliability test assuming the global environment. If the difference in the coefficient of linear thermal expansion from the metal fixing member exceeds ± 5%, the stress applied to the translucent member increases in various reliability tests that are repeatedly performed, and there is a risk of cracks.

In the optical communication package according to the present invention, which meets the above-mentioned object, a semiconductor element for optical communication is housed in a cavity formed by a frame and a bottom, and the cavity can be kept airtight at the same time. In an optical communication package in which a translucent transmissive member is joined to a frame via a metal fixing member, the translucent member is made of Ta-containing borosilicate glass and is within ± 10% of the refractive index of sapphire. And a bending strength of 130 MPa or more and a difference in linear thermal expansion coefficient of ± 5 through the metallized layer formed on the translucent member.
It is joined to the metal fixing member within 100%. Thereby, the light transmission to the semiconductor element for optical communication can be performed with a refractive index close to that of sapphire, and the light transmission with high reliability can be performed. Further, it has a mechanical strength suitable for shape processing without impairing the physical properties of the translucent member. Furthermore, since the difference in thermal expansion coefficient between the metal fixing member and the metal fixing layer is small, the stress applied to the translucent member can be reduced. And since it is a borosilicate glass containing Ta that can be manufactured at low cost,
The cost of the optical communication package can be reduced.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Next, referring to the attached drawings, an embodiment in which the present invention is embodied will be described to provide an understanding of the present invention. Here, FIGS. 1A and 1B are respectively a plan view and a vertical sectional view of a translucent member according to an embodiment of the present invention, and FIGS. 2A and 2B show the present invention. FIG. 4A is a plan view, a longitudinal sectional view of the optical communication package according to the embodiment, and FIG. 3 is an explanatory view showing a state in which a translucent member is joined to a metal fixing member of the optical communication package.
(B) is a perspective view and a partially enlarged sectional view of an optical communication package according to another embodiment of the present invention.

As shown in FIGS. 1A and 1B, the translucent member 10 according to one embodiment of the present invention is formed of borosilicate glass containing Ta in an appropriate amount. The translucent member 10 is manufactured by melting borosilicate glass containing Ta and pouring it into a mold, forming a cylindrical glass rod into slices, grinding or polishing. . The translucent member 10 has a refractive index within ± 10% of sapphire, that is, a refractive index of sapphire of 1.
When it is 76, it has a refractive index in the range of 1.584 to 1.936.

Further, the light-transmissive member 10 is 130M in a three-point bending strength test (specified by JIS C 2141).
It has a bending strength of Pa or more. The upper limit of bending strength is
Although not particularly specified, 300 MPa or less is preferable from the viewpoint of workability when performing shape processing.

The transparent member 10 is the transparent member 10.
Thin metallization layer 11 formed by sputtering or the like
Metal fixing member 31 (see FIG. 3) when joining using a low-temperature brazing material such as Au-Sn brazing or Au-Ge brazing through
The coefficient of linear thermal expansion is within ± 5%. Since the metal fixing member 31 is made of, for example, KV, and the coefficient of linear thermal expansion of KV is 5.3 × 10 ⁻⁶ / K, the coefficient of linear thermal expansion of the translucent member 10 is 5.04.
It becomes -5.56 * 10 < ^-6 > / K. As a result, the linear thermal expansion coefficient of the translucent member 10 and the metal fixing member 31 are extremely close to each other, and the stress in the joining can be relaxed.
The shape of the translucent member 10 is not particularly limited, and may be any shape such as flat plate, spherical, hemispherical, convex, concave.

As shown in FIGS. 2A, 2B and 3.
Optical communication package 20 according to an embodiment of the present invention
Is a frame 21 made of KV or 42 alloy having a thermal expansion coefficient similar to that of ceramic, Cu-W having excellent heat dissipation,
A cavity portion 24 having a bottom body 23 made of Cu-Mo-Cu or the like for mounting a semiconductor element for optical communication therein.
Is formed. The bottom body 23 is provided with a plurality of fixing holes 22 (four in this embodiment) for attaching to a board or the like. Window frame-shaped notches 25 that communicate with the cavity portions 24 are provided on the opposing side walls of the frame body 21, respectively. The window frame-shaped notch 25 has a feed-through substrate 2 made of ceramic and provided with a conductor pattern 26.
7 is fitted and brazed and joined. External connection terminals 28 are butterfly-type brazed to the conductor patterns 26 outside the frame 21. On the other hand, the conductor pattern 26 on the cavity portion 24 side is provided for wire bonding with the semiconductor element. A through hole 29 communicating with the cavity portion 24 is formed on one side wall of the frame body 21 to which the feed-through substrate 27 is not joined. The through hole 29 is inserted into the through hole 29 and brought into contact therewith to braze the metal fixing member 31. It is joined. A seal ring 30 is brazed to the upper end surface of the frame body 21 and the upper end surface of the feed-through substrate 27.

The metal fixing member 31 has an insertion hole 32 in the center.
The insertion hole 32 has a large diameter hole 33 and a stepped portion 3 from the outside.
4, a small diameter hole 35 is formed. The outer peripheral portion of the metal fixing member 31 on the small diameter hole 35 side is reduced in diameter and inserted into the through hole 29 of the frame 21 from the outside, and the through hole 29 and the insertion hole 32 are provided.
The axes are aligned and bonded together. The translucent member 10 for facing the tip of the light of the optical fiber member 36 is brazed and bonded to the step portion 34 via the metallized layer 11 formed on the translucent member 10. In addition,
A small-diameter hole, a stepped portion, and a large-diameter hole may be formed from the outside in the insertion hole of the metal fixing member. In this case, the metal fixing member is inserted into the through hole 29 of the frame body 21 from the inside with the outer diameter of the small diameter hole side being reduced in diameter, and is joined and fixed by aligning the through hole 29 and the axis of the through hole.

In the optical communication package 20, semiconductor elements for optical communication are mounted in the cavity portion 24, and KV, 4
2 A cap (lid body) formed of a metal such as an alloy or a ceramic is joined with a brazing material, resin, glass or the like or seam-welded, and then the optical fiber member 3 is attached to the metal fixing member 31.
6 is welded and attached using a laser such as YAG to be used as a semiconductor device for optical communication.

Next, a method of manufacturing the optical communication package 10 according to the embodiment of the present invention will be described. The frame 21 formed by cutting a metal block such as KV or 42 alloy, which has a thermal expansion coefficient similar to that of ceramics, or by cutting the pipe into slices and then bending them, is further provided on opposite side walls of the frame 21. A window frame-shaped notch 25 having a substantially rectangular shape communicating with the cavity portion 24 is formed. In addition, one side wall of the frame body 21 in which the window frame-shaped notch 25 is not formed is formed with a through hole 2 that communicates with the cavity portion 24 and that has a substantially circular shape.
9 is formed. On the other hand, the bottom body 23 is formed of a metal plate such as copper-tungsten, which is excellent in radiating heat generated from the semiconductor element, and has a fixing hole 22 for attaching to a mounting member such as a board with a screw.

After the Ni plating is applied to the frame 21 and the bottom 23, a high-temperature brazing material such as Ag-Cu brazing material is sandwiched between the joints and heated to be brazed and joined together, so that the inside of the body is exposed to light. A cavity portion 24 for mounting a semiconductor element such as a laser diode or a photodiode for communication is formed. In addition, after the conductor pattern 26 of the feed-through substrate 27 made of ceramic is plated with Ni, the window frame-shaped notch 25 is sandwiched with a high temperature brazing material such as Ag—Cu brazing material and heated to be brazed. To join.

Here, the feed-through substrate 2 made of ceramic such as alumina and joined to the window frame-shaped notch 25.
7 is, for example, a powder obtained by adding an appropriate amount of a sintering aid such as magnesia, silica, and calcia to alumina powder, a plasticizer such as dioctyl phthalate, a binder such as an acrylic resin, and toluene, xylene, alcohols, and the like. Add solvent, knead thoroughly, degas, and viscosity 2000 ~ 40000
A slurry of cps is prepared, a roll-shaped sheet having a thickness of 0.25 mm, for example, is formed by a doctor blade method or the like, and a rectangular sheet cut into an appropriate size is prepared. A conductor pattern is formed on this ceramic green sheet by using a refractory metal such as tungsten or molybdenum, and a laminated body in which each ceramic green sheet is laminated is co-fired with the ceramic and the refractory metal in a reducing atmosphere at about 1550 ° C. To form.

The feed-through board 27 is
The feedthrough substrate 27 is provided in the window frame-shaped cutout 25 described above.
Is fitted and brazed and joined with a high-temperature brazing material such as Ag-Cu braze, a metallized pattern is formed on the outer peripheral portion of the feed-through substrate 27 in contact with the window frame-shaped notch 25, and the frame 21 A conductive pattern 26 for electrical connection between the inside and the outside is formed. An external connection terminal 28 is contacted with the conductor pattern 26 on the outside of the frame body 21 in a butterfly shape, and brazed with a high temperature brazing material such as Ag—Cu brazing. The conductor pattern 26 on the side of the cavity 24 is used to connect the semiconductor element with a bonding wire or the like.

On the other hand, the metal fixing member 31 which is inserted into the through hole 29 and joined thereto can be contacted by first inserting the outer peripheral portion of the metal block such as KV or 42 alloy into the through hole 29 of the frame 21. A step is formed by cutting or the like so that the insertion portion is reduced in diameter. On the inner peripheral side, a large diameter hole 33, a step portion 34, and a small diameter hole 35 are formed from the outside. Next, the reduced diameter portion is inserted into the through hole 29 from the outside or the inside of the frame body 21 through a high temperature brazing material such as Ag-Cu brazing material, and abutted and heated to join. In the brazing joining with the high temperature brazing material such as Ag-Cu brazing material described above, there are a case where each joining portion is heated at one time and joined, and a case where the joining is performed by heating in a plurality of times. is there. After that, the feedthrough substrate 27,
The metal surface to which the external connection terminal 28 and the metal fixing member 31 are joined is plated with Ni and Au.

Next, flat plate, spherical, hemispherical, convex,
In the translucent member 10 having a concave shape or the like, for example, a two-layer structure of Cr-Au, Ti-Cr-, or the like is formed on a portion of the metal fixing member 31 that contacts the step portion 34 by sputtering or the like.
A thin metallized layer 11 having a three-layer structure of Au or the like is formed. Au− through the translucent member 10 and the metallized layer 11
A low-temperature brazing material 37 such as Sn brazing or Au-Ge brazing is used to braze the step portion 34.

As shown in FIGS. 4A and 4B, an optical communication package 20a according to another embodiment of the present invention is
Conductor patterns 41, 42 are formed by screen-printing a refractory metal such as tungsten or molybdenum on a ceramic green sheet made of alumina or the like, a plurality of ceramic green sheets are laminated, and conductor patterns 43, 44 are further formed on the laminated body. The substrate 40 is formed by printing and firing. The base 40 has a cavity 45 for mounting a semiconductor element for optical communication therein and a conductor pattern 41 which is a wire bond pad for connecting the semiconductor element with a bonding wire. In addition, the base 40
Conductor patterns 43 that are electrically connected to the conductor pattern 41 in the cavity portion 45 are provided on opposite side surfaces of the conductor pattern 43. External connection terminals 46 are brazed and joined to the conductor patterns 43 provided on both side surfaces of the base body 40 by using a high-temperature brazing material such as Ag—Cu braze on both side surfaces in a dual in-line type. Further, the conductor pattern 42 provided on the upper surface of the base 40 is covered with a lid made of metal, ceramic, or the like after the semiconductor element is mounted, and a seal ring 47 is provided to seal the inside of the cavity 45 hermetically. -Cu
Brazing is performed using a high temperature brazing material such as brazing.

Further, a through hole 48 communicating with the cavity portion 45 is formed on one side surface of the base body 40 where the external connection terminal 46 is not joined. A tubular metal fixing member 49 is brazed and joined to the conductor pattern 44 provided on the outer peripheral surface of the through hole 48 by using a high temperature brazing material such as Ag—Cu brazing. Then, in the step portion 51 provided in the insertion hole 50 of the metal fixing member 49, the transparent member 1
0 is brazed using a low temperature brazing material 52 such as Au—Sn brazing or Au—Ge brazing through a thin metallized layer 11 formed on the contact surface with the step portion 51. The brazing joining using the above-mentioned high temperature brazing material such as Ag—Cu brazing may be carried out in plural times or at once.

In the optical communication package 20a, a semiconductor element for optical communication is mounted in the cavity 45, and KV, 4
Optical communication is achieved by joining a cap (lid) formed of a metal such as 2 alloy or the like with a brazing material, resin, glass, or by seam welding to attach the optical fiber member to the metal fixing member 49. Used as a semiconductor device for.

[0024]

The light-transmitting member according to claim 1 is a light-transmitting member made of borosilicate glass containing Ta and having a refractive index within ± 10% of the refractive index of sapphire and 1
Compared to sapphire, it has a bending strength of 30 MPa or more and the difference in linear thermal expansion coefficient with the metal fixing member that is brazed through the metallized layer formed on the translucent member is within ± 5%. By adding Ta to borosilicate glass, which is inexpensive and has a low refractive index, the refractive index is brought close to that of sapphire and has optical and electrical properties equivalent to sapphire. A translucent member that has improved physical strength and is suitable for electronic component materials, optical materials, and mechanical component materials, and has a thermal property extremely similar to that of the metal member to be bonded is inexpensive. Borosilicate glass can be provided.

In the package for optical communication according to claim 2, the translucent member is made of borosilicate glass containing Ta, and has a refractive index within ± 10% of the refractive index of sapphire and 1
Since it has a bending strength of 30 MPa or more and is bonded to a metal fixing member having a difference in linear thermal expansion coefficient of ± 5% or less through a metallized layer formed on a translucent member, it is a semiconductor for optical communication. Light can be transmitted to and from the element with a refractive index close to that of sapphire, highly reliable light transmission is possible, and mechanical strength suitable for shape processing can be achieved without impairing the physical properties of the translucent member. have. Since the difference in the coefficient of thermal expansion from the metal fixing member bonded via the metallized layer is extremely small, the stress applied to the translucent member can be reduced, and the bonding reliability can be improved. Since the borosilicate glass containing Ta can be manufactured at low cost, the cost of the optical communication package can be reduced.

[Brief description of drawings]

1A and 1B are a plan view and a vertical sectional view, respectively, of a translucent member according to an embodiment of the present invention.

2A and 2B are a plan view and a vertical sectional view, respectively, of an optical communication package according to an embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a state in which a translucent member is joined to a metal fixing member of the optical communication package.

4A and 4B are respectively a perspective view and a partially enlarged cross-sectional view of an optical communication package according to another embodiment of the present invention.

FIG. 5 is a perspective view of a conventional optical communication package.

FIG. 6 is an explanatory view of a metal fixing member of a conventional optical communication package.

[Explanation of symbols]

10: translucent member, 11: metallized layer, 20, 20
a: package for optical communication, 21: frame body, 22: fixing hole, 23: bottom body, 24: cavity part, 25: window frame cutout, 26: conductor pattern, 27: feedthrough substrate, 28: external Connection terminal, 29: through hole, 30: seal ring, 31: metal fixing member, 32: insertion hole, 33:
Large diameter hole, 34: stepped portion, 35: small diameter hole, 36: optical fiber member, 37: low temperature brazing material, 40: substrate, 41, 4
2, 43, 44: conductor pattern, 45: cavity part,
46: external connection terminal, 47: seal ring, 48: through hole, 49: metal fixing member, 50: insertion hole, 51: step portion, 52: low temperature brazing material

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiromi Watanabe             4-7-25 Harigaya, Saitama City, Saitama Prefecture             Sumita Optical Glass Co., Ltd. F-term (reference) 4G061 AA06 BA00 BA07 BA12 CA03                       CB07 CB14 CD06 DA14 DA23                 4G062 AA04 BB05 DA02 DC02 FH02                       MM02 NN01 NN33

Claims (2)

[Claims] 1. A translucent member made of borosilicate glass containing Ta, having a refractive index within ± 10% of the refractive index of sapphire, and 130.
It has a bending strength of MPa or more, and the difference in the coefficient of linear thermal expansion from the metal fixing member to be brazed and bonded via the metallized layer formed on the translucent member is within ± 5%. A transparent member. 2. A fixing member made of metal for accommodating a semiconductor element for optical communication in a cavity portion formed of a frame and a bottom body, capable of keeping the cavity portion airtight and transmitting light at the same time. In the package for optical communication joined to the frame via the transparent member, the transparent member is made of borosilicate glass containing Ta, and has a refractive index within ± 10% of a refractive index of sapphire and a resistance of 130 MPa or more. A package for optical communication, which has bending strength and is bonded to the metal fixing member having a difference in coefficient of linear thermal expansion of ± 5% or less through a metallized layer formed on the translucent member. .