JP6935251B2 - Package for mounting light emitting element - Google Patents

Description

The present invention relates to a light emitting element mounting package for mounting a light emitting element such as a laser diode.

For example, a metal base plate, a metal frame joined on the surface thereof and having a rectangular frame shape in a plan view, and a holder formed on one side wall of the frame and attached to one end of an optical fiber to penetrate the holder. A pair of ceramic substrates arranged on an insertion portion and a pair of side walls adjacent to and facing the one side wall of the frame and individually penetrating the pair of side walls, and a pair of ceramic substrates penetrating the inside of each ceramic substrate are formed. Also disclosed is an optical communication package including a plurality of conductor portions made of tungsten or molybdenum along the inner and outer directions of the frame, and a plurality of leads individually bonded to the outer end side of the plurality of conductor portions. (See, for example, Patent Document 1).

However, when power is applied to the light emitting element via the conductor portion as in the optical communication package, the electric resistance of the conductor portion made of tungsten or the like is high, so that the electric power to be input to the light emitting element is sufficient. Could not be increased to.
Further, since the ceramic substrate having the conductor portion is inserted into the rectangular through hole formed in the side wall of the frame and fixed, the dimensional tolerance between the inner dimension of the through hole and the outer dimension of the ceramic substrate is strict. If not managed, there is a problem that it becomes difficult to insert the ceramic substrate, or an excessive gap is formed between the ceramic substrate and the through hole, and the airtightness inside the package cannot be maintained. ..

On the other hand, a semiconductor device has also been proposed in which lead terminals (lead pins) are individually penetrated inside a plurality of through holes provided in a metal eyelet (board), and the space inside the through holes is sealed with glass. (See, for example, Patent Document 2).
However, in a sealing structure such as the semiconductor device in which the gap between the lead terminal and the inner wall surface of the through hole is closed with glass, when thermal stress is applied to the eyelet or the lead terminal, the glass cracks or the like. There is a problem that it is difficult to secure the airtightness inside the semiconductor device because the semiconductor device is liable to be damaged or severely damaged.

Japanese Unexamined Patent Publication No. 11-126840 (pages 1 to 5, FIGS. 1 to 5) Japanese Unexamined Patent Publication No. 58-56482 (pages 1 to 5, FIGS. 1 to 4)

INDUSTRIAL APPLICABILITY The present invention provides a package for mounting a light emitting element, which can solve the problems described in the background technology, can easily increase the power input to the light emitting element to be mounted later, and can surely maintain the airtightness inside the package. , Is the subject.

Means for Solving Problems and Effects of Invention

In order to solve the above problems, the present invention provides a through hole through which a lead pin continuously penetrates a substrate having a mounting portion of a light emitting element on the front surface side and a ceramic member joined to the front surface or the back surface side of the substrate. It was created with the idea of forming it individually.
That is, the light emitting element mounting package (claim 1) of the present invention has a front surface and a back surface, and the front surface includes a mounting portion of the light emitting element, or the front surface side has a separate mounting portion. Light emitting with a substrate that can be arranged, a lead pin supported by the substrate, a facing surface facing either the front surface or the back surface of the substrate, and a ceramic member having a facing back surface facing the facing surface. In the device mounting package, a first through hole is formed between the front surface and the back surface of the substrate to allow the lead pin to pass through, and the ceramic member is formed between the facing surface and the facing back surface. has a second through hole penetrating to the said opposite surface has a metallization layer openings formed enclose the second through-hole, the lead pin, said first through hole and the second through the wells were penetrations, and a flange portion extending radially from the shaft portion of the Ridopi down, via a brazing material layer, fixed to the periphery of the opening of the second through-hole of the opposite rear side of the ceramic member The shaft portion of the lead pin and the inner peripheral surface of the second through hole of the ceramic member face each other without passing through the brazing material layer, and the ceramic member passes through the metallized layer. , The first through hole of the substrate is fixed around the opening on the front surface side or the back surface side.

The package can exert the following effects (1) and (2).
(1) Since the lead pin continuously penetrates the first through hole provided in the substrate and the second through hole provided in the ceramic member, the lead pin follows the mounting portion on the surface side of the substrate. An electrical connection with the mounted light emitting element can be directly obtained via a bonding wire or the like. Therefore, it is possible to supply a sufficient current as the electric power to be input to the light emitting element increases.
(2) The lead pin is fixed around the opening on the opposite back surface side in the second through hole of the ceramic member via the flange portion extending in the radial direction thereof, and the ceramic member is the metallized layer. Is fixed around the first through hole provided in the substrate. Therefore, the lead pin is provided through two joint surfaces (plane surfaces), that is, a joint surface between the flange portion and the facing back surface of the ceramic member, and a joint surface between the facing surface of the ceramic member and the front surface or the back surface of the substrate. Since it is supported by the substrate, the airtightness inside the package can be reliably and easily maintained without the conventional strict control of dimensional intersection.

After the light emitting element is mounted on the surface side of the substrate, for example, a box-shaped body (cap) formed into a cylindrical shape having an open bottom surface by pressing a metal plate is brazed or welded. It may be joined and sealed from the outside.
Further, the box-shaped body has a cylindrical shape or a polygonal pillar shape in outer shape, and after the light emitting element is mounted on the mounting portion, the light emitting element is sealed from the outside.
Further, the light emitting element is, for example, a laser diode (LD) or a light emitting diode (LED).
The substrate, lead pin, and box-shaped body are, for example, Kovar (Fe-29% Ni-17% Co), 42 alloy (Fe-42% Ni), 194 alloy (Cu-2.3% Fe-0). It consists of .03% P) and so on.

Further, the surfaces of the substrate, the lead pin, and the box-shaped body are sequentially coated with a gold film having a required thickness, for example, via a nickel film having a required thickness.
Further, the first through holes are formed in a pair of circular shapes or the like at positions separated from each other on the substrate.
Further, the ceramic member is made of alumina, aluminum nitride, mullite and the like.
Further, a plurality (two or more) of the second through holes are formed in parallel and linearly on the ceramic member.
In addition, the metallized layer is made of tungsten (hereinafter, simply referred to as W), molybdenum (hereinafter, simply referred to as Mo), or the like.

The present invention also includes a light emitting element mounting package (claim 2) in which the metallized layer is formed so as to be separated from an opening on the facing surface side of the second through hole.
According to this, the following effect (3) can be obtained.
(3) Since the metallized layer formed on the peripheral side of the facing surface of the ceramic member is separated from the opening of the second through hole that opens in the facing surface, the ceramic member is placed on the front surface or the back surface of the substrate. When fixing around the first through hole in the above, the brazing material or the like arranged along the metallized layer inadvertently comes into contact with the lead pin, making it difficult for problems such as a short circuit to occur.

Further, in the present invention, the light emitting device is formed by joining the substrate and the ceramic member via the metallized layer and a brazing material layer arranged along the metallized layer. A mounting package (claim 3) is also included.
According to this, since the substrate and the ceramic member are firmly bonded to each other via the metallized layer and the brazing material layer, the effects (2) and (3) can be obtained more reliably.
In the brazing material layer, silver brazing (for example, Ag—Cu alloy) is exemplified.

Further, in the present invention, the substrate and the mounting portion of the light emitting element are separate bodies, and the mounting portion of the light emitting element is included in a radiator having a higher thermal conductivity than the substrate. A package for mounting a light emitting element (claimed) having a third through hole penetrating between the front surface and the back surface, and the radiator is fixed to the substrate in a posture of being inserted into the third through hole. Item 4) is also included.
According to this, the heat radiating body having the mounting portion of the light emitting element has a higher thermal conductivity than the substrate and is inserted and fixed in the third through hole, so that the heat radiating body is mounted on the mounting portion later. The heat generated by the light emitting element can be effectively dissipated to the outside of the package via the heat radiating body (hereinafter referred to as effect (4)).
The heat radiating body is made of, for example, a copper, silver, or aluminum alloy, or an alloy based on any one of these.

Further, in the present invention, the third through hole has an arc shape, a rectangular shape, a square shape, or a circular shape in a plan view, and the radiator has an arc pillar shape made of a thermally conductive metal. It has a rectangular parallelepiped shape, a cubic shape, or a cylindrical shape, and has a flange that enables joining with the periphery of the opening of the third through hole on the back surface of the substrate along the periphery of the bottom surface thereof. An element mounting package (claim 5) is also included.
According to this, the heat radiating body is joined to the flange integrally held along the periphery of the bottom surface of the main body and the periphery of the opening of the third through hole on the back surface of the substrate via a brazing material or the like. Therefore, the above-mentioned effects (2) and (4) can be surely achieved.

In addition, the present invention also includes a light emitting device mounting package (claim 6) in which the difference in linear expansion coefficient between the substrate and the ceramic member is 5 ppm (K ^{-1) or less.}
According to this, since the difference in the coefficient of linear thermal expansion between the ^{ceramic member and the substrate is relatively small, 5 ppm (K -1} ) or less, the heat applied to the joint portion between the ceramic member and the substrate is applied. Since the stress is relaxed, the effect (2) can be obtained more reliably.

(A) and (B) are perspective views showing one form of the light emitting element mounting package of the present invention visually different from each other. (A) is a vertical cross-sectional view taken along the line XX in FIG. 1 (A), and (B) is a vertical cross-sectional view taken along the line YY in FIG. 1 (A). (C) is a perspective view showing a radiator. (A) and (B) are perspective views showing the facing front surface side and the facing back surface side of the ceramic member individually. A vertical sectional view showing a usage state of the above package. (A) and (B) are perspective views showing different forms of light emitting element mounting packages with different visual senses. A vertical sectional view showing a usage state of the above package.

Hereinafter, embodiments for carrying out the present invention will be described.
1 (A) and 1 (B) are perspective views showing one form of a light emitting element mounting package (hereinafter, simply referred to as a package) 1a visually from diagonally above or diagonally below, and FIG. 2 (A) is a perspective view. , FIG. 1 (A) is a vertical cross-sectional view taken along the line of arrow XX.
As shown in FIGS. 1 (A), 1 (B), and 2 (A), the package 1a has a substrate 2 having a front surface 3 and a back surface 4 facing each other, and the package 1a projects upward from the surface 3 side of the substrate 2. The mounting portion 7a of the light emitting element, which is the upper surface of the heat radiating body 6, the ceramic plate (ceramic member) 9 arranged on the surface 3 side of the substrate 2, and the ceramic plate 9 and the substrate 2 are individually penetrated. Moreover, it is provided with a pair of lead pins 20 supported by the substrate 2.

The substrate 2 is made of, for example, Kovar, and has a front surface 3 and a back surface 4 having a circular shape in a plan view, and a circumferential side surface 5 located between them. As shown in FIGS. 1B and 2A, a pair of round first through holes 11 are adjacent to each other between the front surface 3 and the back surface 4 of the substrate 2. Further, one third through hole 13 having an arc shape in a plan view penetrates between the front surface 3 and the back surface 4 at different positions of the substrate 2.
Further, the heat radiating body 6 is made of copper, and as shown in FIGS. 2B and 2C, the main body 7 having an arc prism shape including the mounting portion 7a of the light emitting element on the upper surface, and the main body 7 It integrally has a flange 8 projecting from the bottom surface to the peripheral side by a certain width. The heat radiating body 6 is joined between the flange 8 and the back surface 4 by a brazing material layer described later in a posture in which the main body 7 is inserted into the third through hole 13 of the substrate 2 from the back surface 4 side. ..
The heat radiating body 6 and the third through hole 13 may be omitted, and the mounting portion of the light emitting element may be set on any of the surface 3 of the substrate 2.

Further, the ceramic plate 9 is made of, for example, alumina, and as shown in FIGS. 3A and 3B, a rectangular facing surface 10 facing the surface 3 of the substrate 2 and the facing surface 10 It has facing back surfaces 15 having similar shapes facing each other, and a pair of round second through holes 12 penetrate in parallel between the facing front surface 10 and the facing back surface 15.
The difference in linear expansion coefficient between the alumina constituting the ceramic plate 9 and the Kovar constituting the substrate 2 is 5 ppm (K ^-1 ) or less.
In the facing surface 10, the metallized layer 14 covers almost the entire surface of the facing surface 10 so as to be separated from each opening of the pair of second through holes 12 and individually surround the pair of second through holes 12. Is formed. On the other hand, a ring-shaped conductor portion 16 is individually formed around each opening of the second through hole 12 on the facing back surface 15 via a narrow ring-shaped ceramic portion 17. Has been done.
The metallized layer 14 and the conductor portion 16 are made of W or Mo.

In addition, the lead pin 20 is also made of Kovar, and as shown in FIG. 2 (A) and FIG. It integrally has an extended disk-shaped flange portion 22.
As shown in FIGS. 2A and 4, the lead pin 20 and the ceramic plate 9 are arranged on the conductor portion 16 and each of the conductor portions 16 on the facing back surface 15 of the ceramic plate 9. The peripheral side of the lower surface of each of the flange portions 22 of the lead pin 20 and the facing back surface 15 are joined via the brazing material layer 18.
The brazing material layer 18 is made of, for example, silver brazing.

Further, the metallized layer 14 formed on the facing surface 10 side of the ceramic plate 9 and the front brazing material layer 18 arranged along the metallized layer 14 are interposed on the surface 3 side of the substrate 2 and the ceramic plate. 9 is joined. That is, the lead pin 20 is supported by the substrate 2 via the ceramic plate 9, and the shaft portion 21 thereof is located near the center of the first through hole 11 of the substrate 2 and the ceramic plate 9. It continuously penetrates the vicinity of the center of the second through hole 12.
Then, as shown in FIG. 4, a light emitting element 19 such as a laser diode is mounted on the mounting portion 7a of the radiator body 6, and the light emitting element 19 and the upper end portions of the pair of lead pins 20 are connected to each other. Between them, they can be individually conducted via a pair of bonding wires 23.

In addition, as shown in FIG. 4, above the surface 3 of the substrate 2, a metal (for example, Kovar) having a cylindrical shape as a whole and an open bottom surface is formed on the peripheral side of the surface 3. The flange 25 of the cap 24 is joined by brazing or the like. As a result, the cap 24 can reliably seal the upper end side portion of each lead pin 20 including the ceramic plate 9, the light emitting element 19, and the flange portion 22 from the outside.
The ceiling plate of the cap 24 is formed with a through hole 26 with a lens (not shown) in order to emit the light emitted by the light emitting element 19 to the outside. Further, the lead pin 20 can be electrically connected to the outside by inserting the shaft portion 21 into an external connection terminal on the motherboard side such as a printed circuit board (not shown).

5 (A) and 5 (B) are the same perspective views showing the package 1b having a form different from that of the package 1a, and FIG. 6 is a vertical cross-sectional view showing the usage state thereof.
As shown in FIGS. 5A and 5B, the package 1b includes a similar substrate 2, a radiator 6, a ceramic plate 9, and a pair of lead pins 20.
In the package 1b, as shown in FIGS. 5B and 6, the ceramic plate 9 is joined to the back surface 4 side of the substrate 2 in the same manner as described above, and the second through hole in the ceramic plate 9 is formed. A pair of lead pins 20 are individually joined to each vicinity of 12 via the flange portion 22.

Therefore, as shown in FIG. 6, the shaft portion 21 of the lead pin 20 is formed in the vicinity of the center of the first through hole 11 of the substrate 2 and the second through hole of the ceramic plate 9 located coaxially below the center. It continuously penetrates the vicinity of the center of 12.
Further, as shown in FIG. 6, a light emitting element 19 is mounted on the mounting portion 7a of the heat radiating body 6, and a pair of bonding wires are formed between the light emitting element 19 and each of the upper ends of the pair of lead pins 20. It is individually conductive via 23.
Then, by disposing the same metal cap 24 above the surface 3 of the substrate 2, the light emitting element 19 can be sealed from the outside.

According to the packages 1a and 1b, the lead pin 20 continuously penetrates the first through hole 11 provided in the substrate 2 and the second through hole 12 provided in the ceramic plate 9. An electrical connection with the light emitting element 19 to be mounted on the mounting portion 7a on the surface 3 side of the substrate 2 can be directly obtained via the bonding wire 23. Therefore, it is possible to supply a sufficient current as the electric power to be input to the light emitting element 19 increases.
Further, the lead pin 20 is joined (fixed) to and fixed around the opening on the opposite back surface 15 side in the second through hole 12 of the ceramic plate 9 via the flange portion 22 extending in the radial direction thereof. The ceramic plate 9 is fixed to the periphery of the first through hole 11 provided in the substrate 2 via the metallized layer 14 and the brazing material layer 18.

Therefore, the lead pin 20 is referred to as a joint surface between the flange portion 22 and the facing back surface 15 of the ceramic plate 9, and a joint surface between the facing surface 10 of the ceramic plate 9 and the front surface 3 or the back surface 4 of the substrate 2. Since it is supported by the substrate 2 via the two joint surfaces (planes), the airtightness inside the packages 1a and 1b can be reliably and easily maintained without managing strict dimensional intersections as in the past. Can be done.
Further, since the metallized layer 14 formed on the facing surface 10 of the ceramic plate 9 is separated from the opening of the second through hole 12 that opens in the facing surface 10, the ceramic plate 9 is placed on the substrate 2. When fixing around the first through hole 11 on the front surface 3 or the back surface 4, the brazing material 18 arranged along the metallized layer 14 carelessly contacts the lead pin 20 and causes a short circuit or the like. Is less likely to occur.

Moreover, since the heat radiating body 6 having the mounting portion 7a of the light emitting element 19 has a higher thermal conductivity than the substrate 2 and is inserted and fixed in the third through hole 13, the mounting portion will be described later. The heat generated by the light emitting element 19 mounted on the 7a can be effectively dissipated to the outside through the heat radiating body 6.
In addition, since the difference in linear expansion coefficient between the ceramic plate 9 and the substrate 3 is 5 ppm (K ^-1 ) or less, the thermal stress applied to the joint between the ceramic plate 9 and the substrate 3 is relaxed. ing.
Therefore, according to the packages 1a and 1b, the effects (1) to (4) can be surely achieved.

Further, according to the light emitting element mounting package 1a, since the ceramic plate 9 is arranged on the surface 3 side of the substrate 2, the ceramic plate 9 and the substrate 2 are joined by a surface to ensure airtightness. Also in the form, it is possible to reduce the height of the entire package 1a. Further, in the light emitting element mounting package 1b, a recess deeper than the thickness of the ceramic plate 9 is formed on the back surface 4 side of the substrate 2, and the ceramic plate 9 is joined in the recess to form the substrate 2 and the ceramic plate. Even in this embodiment in which the airtightness is ensured by joining the 9 to the surface, it is possible to reduce the height of the entire package 1b. In addition, since the ceramic plate 9 and the substrate 2 are joined by a surface, the opening width of the recess is formed sufficiently larger than the width of the ceramic plate 9, so that it is not necessary to strictly control the dimensional accuracy of the recess. ..

The present invention is not limited to the above-mentioned forms.
For example, the substrate 2, the lead pin 20, and the cap 24 may be made of 42 alloy or 194 alloy.
Further, the substrate may have a shape in which the front surface and the back surface thereof are rectangular (square or rectangular) in a plan view.
Further, the ceramic plate 9 may be made of any one of aluminum nitride, mullite, and glass-ceramic.

Further, the first through hole 11 and the second through hole 12 may be 4, 6, 8, 10, or even 12 or more, respectively, and the ceramic plate 9 corresponds to these. May be used in combination of two or more.
Further, the flange portion 22 of the lead pin 20 may have a regular polygonal shape including a rectangular shape in a plan view.
Further, the light emitting element may be a light emitting diode or the like.
In addition, any of alumina, silicic acid, boron oxide, zinc oxide, lead oxide, calcia, palladium, platinum, copper, gold, or carbon may be used for the brazing material (bonding material) layer.

Further, in the above-described embodiment, the ceramic member is a plate-shaped ceramic plate 9, but the ceramic member may have a structure having at least a plate-shaped portion that can be joined to the substrate 2 on a surface. For example, it may be a ceramic member having a tubular portion that is individually erected from the facing surface 10 of the ceramic plate 9 and is formed so as to surround the opening of each second through hole 12 on the facing surface 10 side. According to this form, the tubular portion is inserted into each of the first through holes 11 formed in the substrate 2, and the plate-shaped portion of the ceramic member is joined to the substrate 2 in a plane to form the present package. The airtightness of the inside can be ensured, and an inadvertent short circuit due to contact between the inner wall surface forming the first through hole 11 and the lead pin 20 penetrating the first through hole 11 can be prevented.

Further, in the above-described embodiment, the difference in the coefficient of linear expansion between the ceramic member and the substrate 2 is set to 5 ppm (K ^-1 ) or less, but as long as the airtightness is ensured at the joint between the ceramic member and the substrate 2. In, it is not limited to this. For example, when the maximum linear length in the joint between the ceramic member and the substrate 2 is 5 mm or less, airtightness is ensured even if ^{the difference in the coefficient of linear expansion is larger than 5 ppm (K -1).} It is possible to join them together.
Further, when the ceramic member and the substrate 2 are joined on the surface, the difference in the coefficient of linear expansion is made larger than ^{5 ppm (K -1) by interposing a member that relieves stress between the two objects.} Even so, it is possible to join with ensured airtightness.

According to the present invention, it is possible to reliably provide a light emitting element mounting package capable of easily increasing the input power to the light emitting element mounted on the surface side of the substrate and reliably maintaining the airtightness inside the package. ..

1a, 1b ... Package for mounting a light emitting element 2 ……………… Substrate 3 ……………… Front side 4 ……………… Back side 6 ……………… Heat radiator 7a ………… Mounting part 8 ………… … Flange 9 ……………… Ceramic plate (ceramic member)
10 ………… Facing front surface 11 ………… 1st through hole 12 ………… 2nd through hole 13 ………… 3rd through hole 14 ………… Metallized layer 15 ………… Facing back surface 18… ……… Brazing material layer 19 ………… Light emitting element 20 ………… Lead pin 21 ………… Shaft 22 ………… Brim

Claims (6)

A substrate having a front surface and a back surface and having a mounting portion of a light emitting element on the front surface or having a separate mounting portion arranged on the front surface side, a lead pin supported by the substrate, and the above. A package for mounting a light emitting element, comprising a facing surface facing either the front surface or the back surface of a substrate and a ceramic member having a facing back surface facing the facing surface.
A first through hole is formed between the front surface and the back surface of the substrate to allow the lead pin to pass through.
The ceramic member has a second through hole penetrating between said opposed surfaces and opposed rear surface, the opposite surface has a metallization layer openings formed enclose the second through hole ,
The lead pin, said first through-hole and the second through hole and penetrations, and a flange portion extending radially from the shaft portion of the Ridopi down, via a brazing material layer, opposite the back surface of the ceramic member It is fixed around the opening of the second through hole on the side and
The shaft portion of the lead pin and the inner peripheral surface of the second through hole of the ceramic member face each other without the brazing material layer.
The ceramic member is fixed to the periphery of the opening on the front surface side or the back surface side in the first through hole of the substrate via the metallize layer.
A package for mounting a light emitting element. The metallized layer is formed so as to be separated from an opening on the opposite surface side of the second through hole.
The package for mounting a light emitting element according to claim 1. The bonding between the substrate and the ceramic member is formed via the metallized layer and a brazing material layer arranged along the metallized layer.
The package for mounting a light emitting element according to claim 1 or 2. The substrate and the mounting portion of the light emitting element are separate bodies, the mounting portion of the light emitting element is included in a radiator having a higher thermal conductivity than the substrate, and the substrate is located between the front surface and the back surface thereof. The radiator has a third through hole that penetrates the third through hole, and the radiator is fixed to the substrate in a posture of being inserted into the third through hole.
The package for mounting a light emitting element according to any one of claims 1 to 3, wherein the package for mounting a light emitting element. The third through hole has an arc shape, a rectangular shape, a square shape, or a circular shape in a plan view, and the radiator has an arc pillar shape, a rectangular parallelepiped shape, a cube shape, or a thermally conductive metal. It has a cylindrical shape and has a flange along the periphery of the bottom surface thereof, which enables joining with the periphery of the opening of the third through hole on the back surface of the substrate.
The package for mounting a light emitting element according to claim 4. The difference in coefficient of linear expansion between the substrate and the ceramic member is 5 ppm (K ^-1 ) or less.
The package for mounting a light emitting element according to any one of claims 1 to 5, wherein the package for mounting a light emitting element.

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