JP2002313973A - Package for optical communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a package for optical communication having airtight reliability without increasing the size of the package. SOLUTION: In the package 10 for optical communication where a through hole 20 for communicating with a cavity section 14 is formed at one sidewall section of a substrate 15 for forming the cavity section 14 to mount a semiconductor device for optical communication to the inside and a translucent member 28 opposing the tip of an optical fiber 27 is provided in an insertion hole 22 of a metal fixing member 21 that is inserted into the through hole 20 for sticking, a step section 25 and a channel 26 are provided. At the step section 25, the through hole 22 of the metal fixing member 21 becomes a small-diameter hole 24 from a large-diameter hole 23 being smaller than the diameter of the through hole 20. The channel 26 is provided in the direction of the insertion hole 22 along the large-diameter hole 23 of the step section 25. A translucent member 28 is joined to the step section 25 by low-melt-point glass 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication package for accommodating a semiconductor device for optical communication, and more particularly, to an optical communication package having a light-transmitting member opposed to the tip of an optical fiber. .

[0002]

2. Description of the Related Art An optical communication package for accommodating a semiconductor element for optical communication has a main body made of ceramic or metal, and a shape of a joint portion of an external connection terminal is a dual in line. There is a package of a type or a butterfly (Butterfly) type or the like. For example, a metal butterfly optical communication package 50
As shown in FIG. 4, Cu-W
(Cu-Mo-Cu (copper-molybdenum-copper joint plate)) such as KV (Fe-Ni-Co-based alloy whose wall has a thermal expansion coefficient similar to that of ceramic;
r (Kovar) ") and 42 alloy (Fe-Ni alloy)
And a base member 52 having a cavity portion 51 for mounting a semiconductor element therein. The optical communication package 50 has a through hole 53 formed in one side wall of the base 52 and communicating with the cavity 51.
And brazed to the outer peripheral portion of the through hole 53,
A metal fixing member 54 made of a metal material such as KV or 42 alloy having an insertion hole 61 for passing an optical signal through the cavity 51 is provided. Further, the optical communication package 50 closes the insertion hole 61 of the metal fixing member 54 by bonding.
A light-transmitting member 55 for maintaining the airtightness in the cavity portion 51 and at the same time facing the tip of the optical fiber is provided. Then, the optical communication package 50 is joined to a window frame formed in a wall located on both sides of one side wall of the base 52, and is formed of a ceramic material such as alumina (Al ₂ O ₃ ).
A feed-through board 57 having a conductive wiring pattern 56 formed to be conductive from the cavity portion 51 side of the base 52 to the outside of the base 52 is provided.
7 has an external connection terminal 58 made of a metal member such as KV or 42 alloy, which is brazed to the conductor wiring pattern 56 on the outer portion of the base 52 formed in the form of a butterfly and electrically connected from the outside. are doing.

This optical communication package 50 is composed of a base 52
A semiconductor element is mounted in the cavity 51 of the substrate 52, and the semiconductor element is connected to the conductor wiring pattern 56 on the side of the cavity 51 of the base 52 formed on the feedthrough substrate 57 by a bonding wire or the like, so that the external connection terminals 58 are formed. And the semiconductor element are brought into conduction. After welding the optical fiber member to the metal fixing member 54 using a laser such as YAG, a lid 59 made of metal, ceramic, or the like is sealed on the upper surface of the base 52 by glass, brazing material, resin, or the like. The optical semiconductor device is formed by joining with a stopper, and the semiconductor device is fixed to a board or the like with screws via the mounting holes 60.

Normally, in order to maintain airtightness in the cavity 51 of the optical communication package 50, for example, as shown in FIG. 5, a light transmitting member 55 made of a lens having a flat or hemispherical shape is used. A low-melting glass 63 is arranged and joined between the metal fixing member 54 and the end face of the translucent member 55, and a step 62 formed in the insertion hole 61 of the metal fixing member 54. The metal fixing member 54 is provided around the through-hole 53 formed in one side wall of the base 52, and is provided with A
The base material 52 is formed using a low-temperature brazing material 64 having a melting point lower than that of the low-melting glass 63 such as u-Sn brazing or Au-Ge brazing.
Is joined to.

[0005]

However, the conventional optical communication package as described above has the following problems. (1) Normally, various reliability tests assuming the global environment are imposed on optical communication packages. The thermal expansion coefficient of the brazing material used in the joint between the base and the metal fixing member, for example, Au-Sn brazing, is 16.0 × 10 ⁻⁶ / ° C., and 4.1 × 10 ^{−6 of} low melting glass. / ° C. or 5.1 × 10 ⁻⁶ / ° C. for a translucent member made of glass. For this reason, for example, in a temperature cycle test between -65 ° C. and 150 ° C. therein, a metal fixing member (a coefficient of thermal expansion in the case of KV) joined through low melting point glass by repeating thermal expansion and contraction. 5.5 × 10 ⁻⁶ / ° C.) and the light-transmitting member, stress is concentrated on the low-melting glass or the light-transmitting member, particularly between the end of the light-transmitting member. Cracks may occur in the optical member, or cracks or peeling may occur at the interface between the metal fixing member or the translucent member and the low-melting glass, and the hermeticity of the cavity may not be maintained. (2) The base and the metal fixing member are connected with a brazing material, for example, Au.
-After heating and joining through a low-temperature brazing material such as Sn brazing or Au-Ge brazing, when cooling is performed with a steep cooling gradient, a large tensile stress is applied to the low melting point glass and the translucent member due to the heat shrinkage of the brazing material. As a result, cracks occur in the low-melting glass or the translucent member, cracks or peeling occur at the interface between the metal fixing member or the translucent member and the low-melting glass, and the airtightness of the cavity portion is maintained. May disappear. (3) In order to reduce the influence of heat shrinkage, the joint between the metal fixing member and the translucent member may be located as far as possible from the joint between the base and the metal fixing member.
In this case, the cylinder length of the metal fixing member becomes long, and the package becomes large. The present invention has been made in view of such circumstances, and has as its object to provide an optical communication package having hermetic reliability without increasing the size of the package.

[0006]

According to the present invention, there is provided an optical communication package according to the present invention, comprising: a cavity formed on one side wall of a base for forming a cavity for mounting a semiconductor element for optical communication therein; An optical communication package in which a through hole communicating with the optical fiber is formed, and a light transmitting member for facing the tip of the optical fiber is provided in the insertion hole of the metal fixing member inserted and fixed in the through hole. The insertion hole of the fixing member has a stepped portion from a large diameter hole smaller than the through hole to a small diameter hole, and a groove is provided in the direction of the insertion hole along the large diameter hole of the stepped portion. The conductive member is joined with the low melting point glass. Thereby, the low-melting glass melted at the time of joining can be stored in the groove provided at the step, and joining with the metal fixing member at the outer peripheral end surface of the translucent member is avoided. Prevents cracks in the translucent member or low-melting glass even when expansion or contraction occurs, and prevents cracking or peeling at the interface between the metal fixing member or the translucent member and the low-melting glass. Can be.

Here, the joint portion between the translucent member and the step portion includes a through hole portion of the base in a plan view, and is positioned inward from the inner wall surface of the base to twice the thickness of the translucent member. It is preferable to provide between the outside wall surface of the base and the position twice the thickness of the translucent member to the outside. Thereby, the joining portion of the translucent member to be joined to the metal fixing member can be close to the wall surface of the base in plan view, and it is not necessary to enlarge the metal fixing member. Enlargement can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the accompanying drawings to provide an understanding of the present invention. 1A and 1B are a plan view and a cross-sectional view of an optical communication package according to an embodiment of the present invention, and FIG. 2 is an enlarged cross-sectional view of a metal fixing member of the optical communication package. FIGS. 3 (A) and 3 (B) are explanatory views of the positions of the joints of the translucent members of the optical communication package.

As shown in FIGS. 1A and 1B, an optical communication package 10 according to an embodiment of the present invention includes a metal frame 11 and a fixing hole for mounting on a board or the like. 1
2 (four in this embodiment) metal bottom plate 1
3 for forming a cavity portion 14 for mounting a semiconductor device for optical communication therein by brazing.
And the opposing walls of the frame 11 of the base 15 have
A window frame-shaped hole 16 communicating with the cavity portion 14 is provided. Each window frame-shaped hole 16 has a conductor pattern 18.
A feed-through board 19 made of a ceramic having the following is fitted and brazed, and the conductor pattern 18 is
The outer connection terminal 1 is brazed to the external connection terminal 17 in a butterfly shape. On the other hand, the semiconductor device is connected to the semiconductor element via the wire bonding or the like on the cavity portion 14 side. A through hole 20 communicating with the cavity 14 is provided on one side wall of the frame 11 to which the feedthrough substrate 19 of the base 15 is not bonded.
Is formed, and a metal fixing member 21 having an insertion hole 22 is inserted into the through hole 20 and fixedly joined thereto.

As shown in FIG. 2, this metal fixing member 2
1 has a step portion 25 in which the diameter of the insertion hole 22 is changed from the large diameter hole 23 smaller than the hole diameter of the through hole 20 formed in the frame body 11 to the small diameter hole 24, and the large diameter hole 23 of the step portion 25 has Along the direction of the insertion hole 22, for example, substantially U
A groove 26 having a V-shape or a V-shape is provided.
A light-transmissive member 28 to be opposed to the front end is joined to the step 25 with a low-melting glass 29. Thus, the translucent member 28 is provided in the insertion hole 22 of the metal fixing member 21. The frame 11 and the metal fixing member 21 are joined with a joining material 30 of a low-temperature brazing material having a melting point lower than the melting point of the low-melting glass 29. In this joining, the low melting point glass 29 that originally joins the circumferential end face of the light transmitting member 28 and the metal fixing member 21 falls into the groove 26 due to heating at the time of joining, and the light transmitting member A gap is formed between the circumferential end surface of the fixing member 28 and the metal fixing member 21. Due to this gap, stress concentration due to thermal expansion and contraction due to heating and cooling of the joining material 30 joining the frame 11 and the metal fixing member 21 affects the light transmitting member 28 and the low melting point glass 29. Can be alleviated,
It is possible to prevent the occurrence of cracks in the translucent member 28 and the low-melting glass 29 and the occurrence of cracks and peeling at the interface between the metal fixing member 21 and the low-melting glass 29.

A joint (joining line) 31 between the translucent member 28 and the step portion 25 is formed in the frame 11 of the base 15 in plan view.
As shown in FIG. 3 (A),
When the translucent member 28 is formed inside the frame 11,
A position at a distance B which is twice the thickness A of the translucent member 28 placed on the metal fixing member 21a inside the inner wall surface 32 on the cavity portion 14 side of the frame body 11 in plan view, and FIG.
As shown in (B), when the translucent member 28 is formed outside the frame 11, the outer wall surface 3 of the frame 11 is viewed in plan.
It is preferable to provide between the position 3 and the distance B which is twice the thickness A of the translucent member 28 placed on the metal fixing member 21b outside. Since the positional relationship between the frame 11 of the base 15 and the translucent member 28 is between them, the groove 26 is formed so that the circumferential end surface of the translucent member 28 and the metal fixing members 21a and 21b are made of low melting glass. 29 can exhibit the effect of not being joined, and even if thermal expansion or contraction occurs in the joining material 30 joining the metal fixing members 21a, 21b and the frame 11, even if the translucent member 28 or the low melting point glass is used. 29, the metal fixing member 21, the light transmitting member 28 and the low melting glass 29
Cracks, peeling, etc. at the interface can be prevented.

The translucent member 28 can be joined to the metal fixing member 21 from the direction of the cavity 14 or from the outside. Low melting glass 29
Ni plating may be applied to the surface of the metal fixing member 21 which is to be joined to the metal fixing member 21 if necessary. When the joining material 30 is a low-temperature brazing material such as Au-Sn brazing or Au-Ge brazing, the surface of the metal fixing member 21 serving as the joining surface and the metal surface of the base 15 are usually plated with Ni or Au. It has been subjected. The shape of the translucent member 28 joined to the metal fixing member 21 may be any of a flat lens, a hemispherical lens, and the like. The material may be any of borosilicate glass, sapphire glass and the like.

The substrate is made of a ceramic green sheet of alumina, glass ceramic, aluminum nitride, or the like, and is subjected to metallization printing, lamination, and sintering, which are manufactured by a method using an ordinary ceramic laminated package forming technique, to obtain a desired conductor. A laminate having a pattern can also be used. In this case, the external connection terminals are brazed to a butterfly type or a dual in-line type. The joining of the base and the metal fixing member 21 is performed by forming a conductive pattern on the base, performing Ni plating and Au plating, and applying Au-
Brazing is performed by using a low-temperature brazing material such as Sn brazing or Au-Ge brazing.

In the above-described optical communication package 10, a semiconductor element for optical communication is mounted in the cavity portion 14, and an optical fiber 27 is attached to the metal fixing member 21 by welding using a laser such as YAG. After, Kovar, 4
A cap (lid) made of a metal such as a two-alloy or ceramic or the like is joined with a brazing material, resin, glass, or the like, and sealed to be used as a semiconductor device for optical communication.

Next, the manufacturing process of the optical communication package 10 according to one embodiment of the present invention will be described. The frame 11 formed by cutting a metal lump such as Kovar or 42 alloy having a coefficient of thermal expansion similar to that of ceramics, or by cutting a pipe into a ring and then bending the same is further provided with one side wall of the frame 11. A substantially rectangular window frame-shaped hole 16 communicating with the cavity portion 14 at opposing walls positioned on both sides.
To form In addition, a substantially circular through hole 20 communicating with the cavity portion 14 is formed in one side wall of the frame body 11 where the window frame-shaped hole 16 is not formed. On the other hand, a bottom plate 13 formed of a metal plate such as copper tungsten which is excellent in radiating heat generated from the semiconductor element and having a fixing hole 12 for mounting to a mounting member such as a board with screws is formed.

After the Ni plating is applied to the frame 11 and the bottom plate 13, a high-temperature brazing material such as Ag-Cu brazing is sandwiched between the joints, and the joint is heated and brazed. A base 15 having a cavity portion 14 for mounting a semiconductor element such as a laser diode, a light emitting diode, or the like is formed. In addition, after Ni plating is applied to the conductor pattern of the feed-through substrate 19 made of ceramic in the window frame-shaped hole 16, a high-temperature brazing material such as Ag-Cu brazing is sandwiched between the joints and heated to be brazed.

Here, the feed-through substrate 19 made of ceramic such as alumina and joined to the window frame-shaped hole 16 is
For example, magnesia, silica, a powder obtained by adding an appropriate amount of a sintering aid such as calcia, a plasticizer such as dioxyl phthalate, and a binder such as an acrylic resin,
Solvents such as toluene, xylene and alcohols are added, kneaded well, and defoamed to a viscosity of 2000 to 40000 cps.
Is prepared, and a roll-shaped sheet having a thickness of, for example, 0.25 mm is formed by a doctor blade method or the like.
It is made from a rectangular sheet cut to an appropriate size. A conductor pattern is formed on this ceramic green sheet using a refractory metal such as tungsten or molybdenum, and the laminated body of the ceramic green sheets is simultaneously fired in a reducing atmosphere at about 1550 ° C. with the ceramic and the refractory metal. Formed. This feed-through board 19
The feed-through board 19 is inserted into the window frame-shaped hole 16 described above.
Into the window frame-shaped hole 16 of the feed-through board 19 in order to braze with a high-temperature brazing material such as Ag-Cu brazing.
A metallized pattern is formed on the outer peripheral portion that comes into contact with the conductive member, and a conductive pattern 18 for conduction between the inside and the outside of the frame 11 is formed.

An external connection terminal 17 is brought into contact with the conductor pattern 18 outside the frame body 11 in a butterfly shape to form an Ag-
Brazing and joining with a high-temperature brazing material such as Cu brazing. The conductor pattern 18 on the side of the cavity 14 is used to connect the semiconductor element with a bonding wire or the like. In the case of brazing with a high-temperature brazing material such as the above-mentioned Ag-Cu brazing material, there are cases where each joint portion is heated and joined at a time, and cases where it is heated and joined in a plurality of times.
After that, the feed-through board 19 and the external connection terminals 17
Ni plating and Au plating are applied to the metal surface of the substrate 15 to which the substrate is bonded.

On the other hand, the metal fixing member 21 for joining to the through hole 20 in one side wall of the frame body 11 to which the feed-through board 19 is not joined is first formed from a metal lump such as Kovar or 42 alloy on the outer periphery. The portion is inserted into the through hole 20 in the side wall of the frame 11 and formed by cutting or the like so as to be able to contact the side surface of the frame 11 around the through hole 20.
At the same time, the insertion hole 22 having the step portion 25 from the large-diameter hole 23 to the small-diameter hole 24 is formed, and substantially along the large-diameter hole 23 of the step portion 25 in the direction of the insertion hole 22 in a cross-sectional view. A U-shaped or V-shaped groove 26 is formed.

Next, a translucent member 28 made of borosilicate glass, sapphire, or the like, and made of a glass plate, a hemispherical lens, or the like is mounted on the step portion 25 via a low melting glass 29 in the form of a glass pellet. The low-melting glass 29 is melted by heating while applying an appropriate pressure, and the translucent member 28 is joined to the step 25. In this bonding, the translucent member 28 can be stably placed by the step portion 25, the low-melting glass 29 flows out by heating and melting, and an appropriate meniscus shape can be formed.
6, the flow of the low-melting glass 29 to the translucent member 28 can be absorbed, so that the gap between the end face of the translucent member 28 and the metal fixing member 21 is not closed by the low-melting glass 29, Can be made.

The feed-through substrate 1 of the base 15
Through hole 20 in one side wall of frame body 11 not joined to 9
Then, a metal fixing member 21 provided with a light transmitting member 28 for facing the tip of the optical fiber 27 is inserted into an insertion hole 22 smaller than the hole diameter of the through hole 20, and a low-temperature brazing material joining material 30 is inserted. To fix it.

It is preferable to use glass having a melting point of 650 ° C. or less as the low melting point glass 29 described above. Thereby, the meniscus of the glass can be formed normally, and the glass plate can be firmly joined to the metal fixing member 21. If the melting point exceeds 650 ° C., a normal meniscus shape cannot be obtained, and the glass plate or the hemispherical lens of the translucent member 28 is softened and deformed. The base 15
Between the frame 11 and the metal fixing member 21 are Au-
A joining material 30 made of a low-temperature brazing material such as Sn brazing or Au-Ge brazing can be used.

In the case of forming a ceramic base, a metallized pattern such as a wire bond pad is formed on a ceramic green sheet manufactured by the above-described method for manufacturing a ceramic green sheet by using a refractory metal such as tungsten or molybdenum. Is formed by screen printing,
A desired portion is perforated so that a cavity portion and a through hole are obtained, each ceramic green sheet is laminated, an outer portion is cut into a laminate, and a surface on which a through hole communicating with the cavity portion is formed. A metallized pattern is formed by screen printing on the portion where the external connection terminals are joined,
A ceramic and a high melting point metal are simultaneously fired in a reducing atmosphere at 50 ° C. to form a film. Then, after applying Ni plating to the metallized pattern of the base, the external connection terminals are joined to a dual in-line type or a butterfly type with a high-temperature brazing material such as Ag-Cu brazing, and further, Ni plating and Au plating are applied to the metal surface. The metal fixing member 21 is made of Au-Sn brazing or Au.
Joining with a low-temperature brazing material such as Ge brazing;

[0024]

According to the first and second aspects of the present invention, the optical communication package has a step portion in which the insertion hole of the metal fixing member is changed from a large-diameter hole to a small-diameter hole smaller than the diameter of the through-hole. A groove is provided along the diameter hole in the direction of the insertion hole, and the translucent member is bonded to the step with low-melting glass, so that the low-melting glass melted at the time of joining can be stored in the groove. A gap is formed between the outer peripheral end surface of the transparent member and the metal fixing member, and even if thermal expansion or contraction occurs due to heating or cooling, cracks occur in the translucent member or low-melting glass, and the metal is fixed. Cracks and peeling at the interface between the member or the light-transmissive member and the low-melting glass can be prevented, and airtight reliability is provided.

[0025] In particular, in the optical communication package according to the second aspect, the joint portion between the translucent member and the step portion includes a through-hole portion of the base in a plan view, and is inward from the inner wall surface of the base. Since it is provided between a position twice the thickness of the light-transmitting member and a position twice the thickness of the light-transmitting member outward from the outer wall surface of the base,
The joining portion of the translucent member to be joined to the metal fixing member can be close to the wall surface of the base in a plan view, and there is no need to make the metal fixing member large, thereby preventing the optical communication package from increasing in size. can do.

[Brief description of the drawings]

FIGS. 1A and 1B are a plan view and a cross-sectional view, respectively, of an optical communication package according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a metal fixing member of the optical communication package.

FIGS. 3A and 3B are explanatory diagrams each showing a position of a bonding portion of a translucent member of the optical communication package. FIGS.

FIG. 4 is a perspective view of a conventional optical communication package.

FIG. 5 is a cross-sectional view of a bonding portion of a translucent member of a conventional optical communication package.

[Explanation of symbols]

10: package for optical communication, 11: frame, 12: fixing hole, 13: bottom plate, 14: cavity, 15: base, 1
6: window frame-shaped hole, 17: external connection terminal, 18: conductor pattern, 19: feed-through board, 20: through hole, 21,
21a, 21b: metal fixing member, 22: insertion hole, 2
3: large diameter hole, 24: small diameter hole, 25: stepped portion, 26: groove,
27: optical fiber, 28: translucent member, 29: low melting point glass, 30: bonding material, 31: bonding portion, 32: inner wall surface, 33: outer wall surface

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H037 BA02 BA11 DA36

Claims (2)

[Claims] 1. A through hole communicating with the cavity is formed in one side wall of a base forming a cavity for mounting a semiconductor element for optical communication therein, and is inserted and fixed to the through hole. In an optical communication package in which a light-transmitting member for facing the tip of an optical fiber is provided in an insertion hole of a metal fixing member, the insertion hole of the metal fixing member has a large diameter smaller than the hole diameter of the through hole. It has a step portion that becomes a small-diameter hole from a hole, and a groove is provided in the insertion hole direction along the large-diameter hole of the step portion, and the translucent member is joined to the step portion with low-melting glass. An optical communication package, comprising: 2. The optical communication package according to claim 1, wherein a joint portion between the translucent member and the step portion includes the through hole portion of the base in plan view, and the inside of the base. Optical communication provided between a position twice as thick as the translucent member inward from the wall surface and a position twice as thick as the translucent member outside the outer wall surface of the base. For package.