Semiconductor packaging stem

Abstract

To provide a stem for semiconductor packaging that can reduce variations in the thickness of the sealing portion that seals the leads. [Solution] The semiconductor package stem comprises a first eyelet having a first through-hole, a second eyelet bonded to the first eyelet and having a second through-hole communicating with the first through-hole, leads inserted into the first and second through-holes, and a sealing portion that seals the leads within the first through-hole. In plan view, the opening area of ​​the second through-hole is smaller than the opening area of ​​the first through-hole, and the dielectric constant around the leads within the second through-hole is smaller than the dielectric constant of the sealing portion.

Description

Technical Field

[0001] The present invention relates to a stem for semiconductor packages. Background Art

[0002] In a stem for a semiconductor package on which a semiconductor element is mounted, for example, a structure is known in which a large-diameter first hole is provided on the lower surface side of a disk-shaped eyelet, a small-diameter second hole is provided on the upper surface side, the first hole and the second hole are communicated with each other, a lead is inserted therethrough, and a sealing portion for sealing the lead is provided in the first hole. Prior Art Documents Patent Documents

[0003] Patent Document 1 Japanese Unexamined Patent Publication No. Hei 6-29451 Summary of the Invention Problems to be Solved by the Invention

[0004] In the stem for semiconductor packages as described above, it is difficult to control the thickness of the sealing portion located in the first hole of the eyelet to a value as designed. Variations in the thickness of the sealing portion affect the characteristic impedance of the lead.

[0005] The present invention has been made in view of the foregoing points, and an object of the present invention is to provide a stem for a semiconductor package that can reduce variations in the thickness of a sealing portion that seals a lead. Means for Solving the Problems

[0006] The semiconductor package stem comprises a first eyelet having a first through-hole, a second eyelet bonded to the first eyelet and having a second through-hole communicating with the first through-hole, leads inserted into the first and second through-holes, and a sealing portion that seals the leads within the first through-hole. In plan view, the opening area of ​​the second through-hole is smaller than the opening area of ​​the first through-hole, and the dielectric constant around the leads within the second through-hole is smaller than the dielectric constant of the sealing portion. [Effects of the Invention]

[0007] According to the disclosed technology, it is possible to provide a stem for semiconductor packaging that can reduce variations in the thickness of the sealing portion that seals the leads. [Brief explanation of the drawing]

[0008] [Figure 1] This figure illustrates a stem for a semiconductor package according to the first embodiment. [Figure 2] This is a cross-sectional view illustrating a stem for a semiconductor package according to the first embodiment. [Figure 3] This is a cross-sectional view illustrating a cap attached to a semiconductor package stem according to the first embodiment. [Figure 4] This is a cross-sectional view illustrating a semiconductor package stem according to Modification 1 of the First Embodiment. [Figure 5] This is a cross-sectional view illustrating a semiconductor package stem according to a modified example 2 of the first embodiment. [Figure 6] This figure illustrates a semiconductor package stem according to the second embodiment. [Figure 7] This is a cross-sectional view illustrating a stem for a semiconductor package according to the second embodiment. [Figure 8] This is a cross-sectional view illustrating a semiconductor package stem according to a modified example 1 of the second embodiment. [Figure 9] This is a cross-sectional view illustrating how a cap is attached to a stem for a semiconductor package according to Modification 1 of the second embodiment. [Modes for carrying out the invention]

[0009] The embodiments for carrying out the invention will be described below with reference to the drawings. In each drawing, the same reference numerals are used for identical components, and redundant explanations may be omitted.

[0010] <First Embodiment> Figure 1 is an example of a semiconductor package stem according to the first embodiment, where Figure 1(a) is a perspective view and Figure 1(b) is a plan view. Figure 2 is an example of a semiconductor package stem according to the first embodiment, where Figure 2(a) shows a cross-section along line AA in Figure 1(b) and Figure 2(b) shows a cross-section along line BB in Figure 1(b).

[0011] Referring to Figures 1 and 2, the semiconductor package stem 1 has an eyelet 10, leads 21, 22, 23, 24, and sealing portions 31 and 32. The semiconductor package stem 1 can be used, for example, as a stem for an optical communication laser.

[0012] Furthermore, unless there is a need to distinguish between lead 21, lead 22, lead 23, and lead 24, they will simply be referred to as "leads."

[0013] The eyelet 10 includes a first eyelet 11 and a second eyelet 12 joined on the first eyelet 11. The first eyelet 11 can be made of, for example, iron, Kovar, or a nickel-iron alloy. The material constituting the second eyelet 12 may be the same as the material constituting the first eyelet 11, or it may be a material with high thermal conductivity such as copper.

[0014] The first eyelet 11 comprises, for example, a main body portion 11a and a flange portion 11f. The main body portion 11a is, for example, disc-shaped. The diameter of the main body portion 11a is not particularly limited and can be appropriately determined depending on the purpose, but for example, it may be φ3.8 mm, φ5.6 mm, or φ9.0 mm.

[0015] In the present application, the term "disk shape" refers to an object having a substantially circular planar shape and a predetermined thickness. There is no limitation on the ratio of thickness to diameter. The term also includes objects partially formed with recesses, protrusions, through-holes and the like. Further, in the present application, the term "in planar view" refers to viewing an object from the normal direction of the upper surface of the eyelet 10, and the term "planar shape" refers to the shape of an object viewed from the normal direction of the upper surface of the eyelet 10.

[0016] The flange portion 11f is a plate-shaped member annularly protruding outward from the lower end of the side surface of the main body portion 11a in planar view. The flange portion 11f is, for example, ring-shaped. The width of the flange portion 11f can be, for example, approximately 0.5 mm to 0.8 mm. The flange portion 11f can be formed integrally with the main body portion 11a, for example. Note that the main body portion 11a does not necessarily need to include the flange portion 11f.

[0017] The main body portion 11a is provided with through-holes 11x and 11y penetrating from the upper surface to the lower surface. In the illustrated example, one elongated through-hole 11x in planar view and two circular through-holes 11y in planar view are provided in the main body portion 11a.

[0018] The second eyelet 12 is, for example, disk-shaped. The lower surface of the second eyelet 12 is bonded to the upper surface of the first eyelet 11 by, for example, a metal brazing material (silver solder, gold-tin alloy, etc.) or a conductive adhesive. Note that the upper surface of the first eyelet 11 refers to the upper surface of the main body portion 11a. The diameter of the lower surface of the second eyelet 12 can be, for example, the same as the diameter of the upper surface of the first eyelet 11. The diameter of the lower surface of the second eyelet 12 may be smaller than the diameter of the upper surface of the first eyelet 11.

[0019] The second eyelet 12 is provided with through holes 12x and 12y that penetrate from the top surface to the bottom surface. In the illustrated example, the second eyelet 12 is provided with one elongated through hole 12x and two circular through holes 12y in plan view. Through hole 12x communicates with through hole 11x, and through hole 12y communicates with through hole 11y. In plan view, the opening area of ​​through hole 12x is smaller than the opening area of ​​through hole 11x. In plan view, the opening area of ​​through hole 12y may be the same size as the opening area of ​​through hole 11y. Here, the opening areas of through holes 11x and 11y are defined at a position in the plane including the top surface of the first eyelet 11. Also, the opening areas of through holes 12x and 12y are defined at a position in the plane including the top surface of the second eyelet 12.

[0020] The thickness of the eyelet 10 can be, for example, about 0.4 mm to 2 mm. Preferably, the thickness of the eyelet 10 is 0.8 mm or more, and preferably, the thickness of the main body portion 11a of the first eyelet 11 is 0.45 mm or more. By making the thickness of the main body portion 11a 0.45 mm or more, it becomes easier to ensure airtightness by providing a sealing portion 31 inside the through hole 11x. The thickness of the flange portion 11f can be, for example, 0.2 mm to 0.3 mm.

[0021] Leads 21 and 22 are inserted into through holes 11x and 12x with their longitudinal direction oriented in the thickness direction of the eyelet 10. Leads 21 and 22 are sealed around the periphery of the sealing portion 31 within the through hole 11x, but are not sealed around the periphery of the sealing portion 31 within the through hole 12x. Within the through hole 12x, the area around leads 21 and 22 is air. The thickness of the sealing portion 31 is, for example, the same as the thickness of the first eyelet 11. The upper surface of the sealing portion 31 is, for example, flush with the upper surface of the first eyelet 11. The lower surface of the sealing portion 31 is, for example, flush with the lower surface of the first eyelet 11.

[0022] Leads 23 and 24 are inserted into through holes 11y and 12y with their longitudinal direction oriented in the thickness direction of the eyelet 10. Leads 23 and 24 are sealed around the periphery of the sealing portion 32 within the through hole 11y, but are not sealed around the periphery of the sealing portion 32 within the through hole 12y. Within the through hole 12y, the area around leads 23 and 24 is air. The thickness of the sealing portion 32 is, for example, the same as the thickness of the first eyelet 11. The upper surface of the sealing portion 32 is, for example, flush with the upper surface of the first eyelet 11. The lower surface of the sealing portion 32 is, for example, flush with the lower surface of the first eyelet 11.

[0023] Each lead protrudes upward from the upper surface of the eyelet 10. The amount of protrusion is, for example, about 0.1 mm to 0.3 mm. Each lead also protrudes downward from the lower surface of the eyelet 10. The amount of protrusion of each lead from the lower surface of the eyelet 10 is, for example, about 6 to 10 mm. Each lead is made of a metal such as an iron-nickel alloy or Kovar, and a gold plating or the like may be formed on the surface of each lead.

[0024] Leads 21 and 22 are positioned adjacent to each other and serve as pathways for signals electrically connected to the light-emitting element when the light-emitting element is mounted on the semiconductor package stem 1 and used as a semiconductor package. Leads 23 and 24 serve as pathways for signals electrically connected to, for example, the power supply or elements and sensors mounted on the semiconductor package stem 1. Elements and sensors mounted on the semiconductor package stem 1 include, for example, Peltier elements and temperature sensors. The number of leads is not limited and may be increased or decreased as needed.

[0025] The wire diameter of each lead is, for example, approximately 0.2 mm to 0.6 mm. As described above, leads 21 and 22 serve as the path for signals that are electrically connected to the light-emitting element mounted on the semiconductor package stem 1. Therefore, in order to increase the impedance, it is preferable that leads 21 and 22 have the thinnest possible wire diameter. Considering strength and impedance, it is preferable that the wire diameter of leads 21 and 22 be 0.2 mm to 0.25 mm.

[0026] On the other hand, it is preferable to make the leads 23 and 24 used for power supplies etc. somewhat thicker to reduce impedance, and specifically, taking into consideration the size of the product, it is preferable to make them 0.3 mm or more and 0.6 mm or less in diameter. Thus, in the semiconductor package stem 1, it is preferable that the wire diameter of the leads that serve as the path for signals electrically connected to the light-emitting elements mounted on the semiconductor package stem 1 is thinner than the wire diameter of the other leads.

[0027] The sealing portions 31 and 32 are made of an insulating material such as glass. The materials of sealing portion 31 and sealing portion 32 may be the same or different. When glass is used for sealing portion 31, the dielectric constant of the glass is preferably 4 or more and 7 or less, more preferably 4 or more and 6 or less, and even more preferably 4 or more and 5 or less. Examples of glass with a dielectric constant of 4 or more and 7 or less include glass containing Na2O, BaO, and SiO2, and glass containing Na2O, Al2O3, B2O3, and SiO2. Furthermore, in order to obtain good high-frequency characteristics, the tanδ of the glass used for sealing portion 31 is 5 × 10⁻¹⁰. -4 The following are preferable.

[0028] To seal leads 21 and 22 with the sealing portion 31, first, leads 21 and 22, along with the uncured material that will become the sealing portion 31, are placed in the through-hole 11x of the first eyelet 11. Then, the uncured material that will become the sealing portion 31 is sandwiched from above and below by flat plates or the like, and cured to form the sealing portion 31. This makes it possible to make the upper surface of the sealing portion 31 flush with the upper surface of the first eyelet 11, and the lower surface of the sealing portion 31 flush with the lower surface of the first eyelet 11. In other words, it is possible to realize a semiconductor package stem 1 that can reduce variations in the thickness of the sealing portion 31 that seals leads 21 and 22.

[0029] Furthermore, to reduce variations in the thickness of the sealing portion 31, it is not necessary to place high-melting-point glass above and below the sealing portion 31 within the semiconductor package stem 1, nor is it necessary to apply a treatment to the inner wall surface of the through-hole 12x that makes it difficult to bond with the uncured material that will become the sealing portion 31. Therefore, variations in the thickness of the sealing portion 31 can be reduced without increasing processing costs or decreasing yield.

[0030] Furthermore, in the semiconductor package stem 1, a sealing portion 31 made of an insulating material such as glass with a dielectric constant higher than that of air is arranged around the leads 21 and 22 within the through hole 11x. In addition, within the through hole 12x, the area around the leads 21 and 22 is air. With this structure, a predetermined characteristic impedance (e.g., 50Ω) can be achieved when the opening area of ​​the through hole 12x is smaller than the opening area of ​​the through hole 11x in a plan view. Moreover, since the opening area of ​​the through hole 12x is smaller than the opening area of ​​the through hole 11x, it becomes easier to secure the upper surface area of ​​the second eyelet 12 while achieving the predetermined characteristic impedance, and the arrangement of semiconductor elements and the like becomes easier.

[0031] Furthermore, the dielectric constant around the leads 21 and 22 within the through hole 12x may be something other than air, as long as it is lower than the dielectric constant of the sealing portion 31. For example, a resin with a lower dielectric constant than the sealing portion 31 may be placed around the leads 21 and 22 within the through hole 12x. In this case, the leads 21 and 22 can be more firmly fixed to the eyelet 10.

[0032] Figure 3 is a cross-sectional view illustrating a semiconductor package stem with a cap attached according to the first embodiment. As shown in Figure 3, the semiconductor package stem 1 can be used after mounting semiconductor elements etc. on the eyelets 10 and then attaching the cap 150 to the eyelets 10.

[0033] The cap 150 is made of a metal such as iron, iron-nickel alloy, or Kovar, and has an opening 150x in the approximate center when viewed from above. The transparent member 160 is made of a material such as glass and is fixed to the cap 150 with low-melting-point glass or adhesive so as to close the opening 150x. The cap 150 has a flange portion 150f that protrudes outward in an annular shape from the lower end of its side surface when viewed from above.

[0034] The cap 150, to which the transparent member 160 is fixed, is positioned such that the flange portion 150f is located on the flange portion 11f of the first eyelet 11, and can be joined to the eyelet 10 by resistance welding or the like. This allows the eyelet 10 and the cap 150 to which the transparent member 160 is fixed to form an airtight space.

[0035] <Variations of the first embodiment> A modified example of the first embodiment shows a semiconductor package stem in which the shapes of the first and second eyelets differ from those of the first embodiment. In the modified example of the first embodiment, descriptions of components that are the same as those described in the previously described embodiment may be omitted.

[0036] Figure 4 is a cross-sectional view illustrating a semiconductor package stem according to Modification 1 of the First Embodiment. The semiconductor package stem 1A shown in Figure 4 differs from the semiconductor package stem 1 in that the first eyelet 11 and the second eyelet 12 have a recessed structure in which they fit together.

[0037] In the semiconductor package stem 1A, the upper surface of the first eyelet 11 is provided with a protrusion 111 that projects relative to the upper surface of the sealing portion 31. The lower surface of the second eyelet 12 is provided with a recess 121. The protrusion 111 of the first eyelet 11 engages with the recess 121 of the second eyelet 12.

[0038] The protrusions 111 and recesses 121 can be provided, for example, on the outer circumference of the eyelet 10 in a plan view. The protrusions 111 and recesses 121 can be provided in an annular shape on the outer circumference of the eyelet 10 in a plan view. The protrusions 111 and recesses 121 can be provided, for example, in a portion of the outer circumference of the eyelet 10 in a plan view. In this case, the uneven structure of the first eyelet 11 and the second eyelet 12 can serve to prevent the rotation of the first eyelet 11 and the second eyelet 12.

[0039] The convex portion 111 and the concave portion 121 may be provided in any region other than the outer circumference of the eyelet in a plan view.

[0040] Figure 5 is a cross-sectional view illustrating a semiconductor package stem according to a modification 2 of the first embodiment. The semiconductor package stem 1B shown in Figure 5 differs from the semiconductor package stem 1A shown in Figure 4 in the uneven structure of the first eyelet 11 and the second eyelet 12.

[0041] In the semiconductor package stem 1B, the upper surface of the first eyelet 11 is provided with a recess 112 that is recessed relative to the upper surface of the sealing portion 31. Additionally, the lower surface of the second eyelet 12 is provided with a protrusion 122. The recess 112 of the first eyelet 11 engages with the protrusion 122 of the second eyelet 12.

[0042] The recesses 112 and protrusions 122 can be provided, for example, on the outer circumference of the eyelet 10 in a plan view. The recesses 112 and protrusions 122 can be provided in an annular shape on the outer circumference of the eyelet 10 in a plan view. The recesses 112 and protrusions 122 can be provided, for example, in a portion of the outer circumference of the eyelet 10 in a plan view. In this case, the recessed and convex structures of the first eyelet 11 and the second eyelet 12 can serve to prevent rotation of the first eyelet 11 and the second eyelet 12.

[0043] The recessed portion 112 and the protruding portion 122 may be provided in any region other than the outer circumference of the eyelet in a plan view.

[0044] As shown in Figures 4 and 5, the first eyelet 11 and the second eyelet 12 have a recessed structure that allows them to fit together, making it easy to align the second eyelet 12 with the first eyelet 11 when joining the second eyelet 12 onto the first eyelet 11.

[0045] <Second Embodiment> Figure 6 illustrates a semiconductor package stem according to the second embodiment, where Figure 6(a) is a perspective view and Figure 6(b) is a plan view. Figure 7 is a cross-sectional view illustrating a semiconductor package stem according to the second embodiment, where Figure 7(a) shows a cross-section along the CC line in Figure 6(b), and Figure 7(b) shows a cross-section along the DD line in Figure 6(b).

[0046] Referring to Figures 6 and 7, the semiconductor package stem 2 includes an eyelet 50, leads 61, 62, 63, 64, 65, 66, sealing portions 71 and 72, and a substrate 80. The semiconductor package stem 2 can be used, for example, as a stem for an optical communication laser. The substrate 80 is provided as needed.

[0047] The eyelet 50 includes a first eyelet 51 and a second eyelet 52 joined to the first eyelet 51. The lower surface of the second eyelet 52 is joined to the upper surface of the first eyelet 51 by, for example, a metal brazing material (silver brazing, gold-tin alloy, etc.) or a conductive adhesive. The materials of the first eyelet 51 and the second eyelet 52 can be selected from, for example, the materials exemplified as the materials of the first eyelet 11 and the second eyelet 12. The thickness of the first eyelet 51 and the second eyelet 52 can be, for example, the same as the thickness of the first eyelet 11 and the second eyelet 12.

[0048] The first eyelet 51 and the second eyelet 52 are, for example, disc-shaped. The diameter of the first eyelet 51 is, for example, the same as the diameter of the second eyelet. The diameters of the first eyelet 51 and the second eyelet 52 are not particularly limited and can be appropriately determined depending on the purpose, but for example they are φ3.8 mm, φ5.6 mm, or φ9.0 mm. The first eyelet 51, like the first eyelet 11, may have a flange portion that protrudes outward in an annular shape from the lower end of its side surface in a plan view.

[0049] The first eyelet 51 is provided with through holes 51x and 51y that penetrate from the top surface to the bottom surface. In the illustrated example, the first eyelet 51 is provided with one through hole 51x that is approximately semicircular in plan view and five through holes 51y that are circular in plan view.

[0050] The second eyelet 52 is provided with through holes 52x and 52y that penetrate from the top surface to the bottom surface. In the illustrated example, the second eyelet 52 is provided with one through hole 52x that is approximately semicircular in plan view and five through holes 52y that are circular in plan view. The through hole 52x communicates with the through hole 51x, and the through hole 52y communicates with the through hole 51y. In plan view, the opening area of ​​the through hole 52x is smaller than the opening area of ​​the through hole 51x. In plan view, the opening area of ​​the through hole 52y may be the same as the opening area of ​​the through hole 51y. Here, the opening areas of the through holes 51x and 51y are defined at a position in the plane including the top surface of the first eyelet 51. Also, the opening areas of the through holes 52x and 52y are defined at a position in the plane including the top surface of the second eyelet 52.

[0051] The second eyelet 52 is provided with a substrate placement portion 55. The substrate placement portion 55 is a columnar member that protrudes from the upper surface of the second eyelet 52. The side of the substrate placement portion 55 facing the lead 61 is a substrate fixing surface for fixing the substrate 80. The substrate placement portion 55 is, for example, a rectangular parallelepiped, but it can be any shape as long as it can fix the substrate 80. The substrate placement portion 55 can be integrally formed with the portion of the second eyelet 52 excluding the substrate placement portion 55 by press working or the like. Considering the processability in press working, it is preferable that the thickness of the portion of the second eyelet 52 excluding the substrate placement portion 55 is 0.8 mm or more.

[0052] The substrate 80 is fixed to the substrate fixing surface of the substrate placement section 55. The front surface of the substrate 80 (the side facing the leads 61) is provided with wiring including, for example, signal patterns and ground patterns. The back surface of the substrate 80 (the side facing the substrate placement section 55) is provided with, for example, a solid ground pattern. The ground pattern on the front surface and the ground pattern on the back surface of the substrate 80 can be electrically connected via through-holes that penetrate the substrate 80.

[0053] The back side of the substrate 80 is fixed to the substrate fixing surface of the substrate placement area 55 with a conductive material such as a metal brazing material (for example, a gold-tin alloy). As a result, the grounding pattern on the back side of the substrate 80 is electrically connected to the substrate placement area 55, and the substrate placement area 55 becomes GND potential (reference potential).

[0054] The substrate 80 is made of, for example, ceramics. More specifically, the substrate 80 is made of, for example, aluminum oxide (alumina) or aluminum nitride. The signal pattern and ground pattern can be formed from, for example, tungsten, titanium, gold, etc. Gold plating or the like may be formed on the surface of the signal pattern and ground pattern.

[0055] The lead 61 is inserted into the through holes 51x and 52x with its longitudinal direction oriented in the thickness direction of the eyelet 50. The lead 61 is sealed around its periphery by the sealing portion 71 within the through hole 51x, but not within the through hole 52x. Within the through hole 52x, the area around the lead 61 is air. The thickness of the sealing portion 71 is, for example, the same as the thickness of the first eyelet 51. The upper surface of the sealing portion 71 is, for example, flush with the upper surface of the first eyelet 51. The lower surface of the sealing portion 71 is, for example, flush with the lower surface of the first eyelet 51.

[0056] Leads 62-66 are inserted into through holes 51y and 52y with their longitudinal direction oriented in the thickness direction of the eyelet 50. Leads 62-66 are sealed around the periphery of the sealing portion 72 within the through hole 51y, but not within the through hole 52y. Within the through hole 52y, the area around leads 62-66 is air. The thickness of the sealing portion 72 is, for example, the same as the thickness of the first eyelet 51. The upper surface of the sealing portion 72 is, for example, flush with the upper surface of the first eyelet 51. The lower surface of the sealing portion 72 is, for example, flush with the lower surface of the first eyelet 51.

[0057] Each lead protrudes upward from the upper surface of the eyelet 50. Each lead also protrudes downward from the lower surface of the eyelet 50. The amount of protrusion of each lead from the upper and lower surfaces of the eyelet 50 can be, for example, the same as in the first embodiment. The material of leads 61-66 can be, for example, the same as that of leads 21-24.

[0058] The portion of lead 61 that protrudes upward from the upper surface of the eyelet 50 is electrically connected to the signal pattern on the substrate 80 by a conductive bonding material 90 such as a metal brazing material (e.g., gold-tin alloy). Lead 61 serves as a path for signals that are electrically connected to the light-emitting element mounted on the semiconductor package stem 2 via the signal pattern. Leads 62 to 66 serve as paths for signals that are electrically connected to, for example, a power supply or elements and sensors mounted on the semiconductor package stem 2. Elements and sensors mounted on the semiconductor package stem 2 include, for example, Peltier elements and temperature sensors. The number of leads is not limited and may be increased or decreased as needed.

[0059] The wire diameter of each lead is, for example, approximately 0.2 mm to 0.6 mm. As described above, the lead 61 is the path through which signals electrically connected to the light-emitting element mounted on the semiconductor package stem 2 pass. Therefore, in order to increase the impedance, it is preferable that the wire diameter of the lead 61 be as thin as possible. Considering strength and impedance, it is preferable that the wire diameter of the lead 61 be 0.2 mm to 0.25 mm.

[0060] On the other hand, it is preferable to make the leads 62-66 used for power supplies etc. somewhat thicker to reduce impedance, and specifically, taking into consideration the size of the product, it is preferable to make them 0.3 mm to 0.6 mm in diameter. Thus, in the semiconductor package stem 2, it is preferable that the wire diameter of the leads that serve as the path for signals electrically connected to the light-emitting elements mounted on the semiconductor package stem 2 is thinner than the wire diameter of the other leads.

[0061] The sealing portions 71 and 72 can be made of the same insulating material as the sealing portions 31 and 32, for example. The dielectric constant around the lead 61 within the through hole 52x may be something other than air, as long as it is lower than the dielectric constant of the sealing portion 71. For example, a resin with a lower dielectric constant than the sealing portion 71 may be placed around the lead 61 within the through hole 52x. In this case, the lead 61 can be fixed more firmly to the eyelet 50.

[0062] The semiconductor package stem 2 can achieve the same effects as the semiconductor package stem 1.

[0063] <Variations of the second embodiment> A modified example of the second embodiment shows a semiconductor package stem with a different eyelet shape from that of the second embodiment. In the modified example of the second embodiment, descriptions of components that are the same as those described in the previously described embodiment may be omitted.

[0064] Figure 8 is a cross-sectional view illustrating a semiconductor package stem according to Modification 1 of the second embodiment, and shows the cross-section corresponding to Figure 7. The semiconductor package stem 2A shown in Figure 8 differs from the semiconductor package stem 2 in that, in a plan view, the second eyelet 52 is smaller than the first eyelet 51.

[0065] In the semiconductor package stem 2A, the first eyelet 51 is exposed in an annular shape on the outer circumference of the second eyelet 52 when viewed from above. For example, the planar shape of the first eyelet 51 is circular, and the planar shape of the second eyelet 52 is a smaller diameter circle than the first eyelet 51, and the two are arranged concentrically.

[0066] Thus, by arranging the eyelet 51 in an annular shape exposed on the outer circumference of the second eyelet 52 in a plan view, it becomes easy to attach a cap to the eyelet 50. This will be explained below with reference to Figure 9.

[0067] Figure 9 is a cross-sectional view illustrating a semiconductor package stem with a cap attached, according to Modification 1 of the second embodiment. As shown in Figure 9, the semiconductor package stem 2A can be used by attaching a cap 150, similar to that in Figure 3, to the eyelet 50 by resistance welding or the like after mounting semiconductor elements or the like to the eyelet 50. This allows for the formation of an hermetically sealed space between the eyelet 50 and the cap 150 to which the transparent member 160 is fixed.

[0068] Although preferred embodiments have been described in detail above, the embodiments are not limited to those described above, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of the claims. For example, in the semiconductor package stems 2 and 2A, a recessed structure in which the first eyelet and the second eyelet fit together may be provided, similar to the semiconductor package stem 1A or 1B. [Explanation of symbols]

[0069] 1,1A,1B,2,2A Semiconductor package stems 10.50 eyelets 11.51 First eyelet 11a Main body 11f flange section 12.52 Second eyelet 11x,11y,12x,12y,51x,51y,52x,52y through hole 21,22,23,24,61,62,63,64,65,66 Lead 31, 32, 71, 72 Sealing section 55 Substrate placement section 80 circuit boards 90 Conductive bonding material 111,122 Convex parts 112,121 recess 150 caps 150f flange section 150x aperture 160 Transparent component

Claims

1. A first eyelet provided with a first through hole, A second eyelet is joined to the first eyelet and has a second through hole that communicates with the first through hole, Leads inserted into the first through hole and the second through hole, The device has a sealing portion that seals the lead within the first through hole, In a plan view, the opening area of ​​the second through-hole is smaller than the opening area of ​​the first through-hole. A stem for a semiconductor package, wherein the dielectric constant around the lead within the second through-hole is smaller than the dielectric constant of the sealing portion.

2. The semiconductor package stem according to claim 1, wherein the upper surface of the sealing portion is flush with the upper surface of the first eyelet, and the lower surface of the sealing portion is flush with the lower surface of the first eyelet.

3. The upper surface of the first eyelet is provided with a protrusion that projects relative to the upper surface of the sealing portion. The stem for a semiconductor package according to claim 1 or 2, wherein the protrusion engages with a recess provided on the lower surface of the second eyelet.

4. The upper surface of the first eyelet is provided with a recess that is recessed relative to the upper surface of the sealing portion. The semiconductor package stem according to claim 1 or 2, wherein the recess engages with a protrusion provided on the lower surface of the second eyelet.

5. The semiconductor package stem according to claim 1 or 2, wherein the first eyelet comprises a main body portion and a flange portion that protrudes outward in an annular shape in a plan view from the lower end of the side surface of the main body portion.

6. The semiconductor package stem according to claim 1 or 2, wherein, in a plan view, the first eyelet is exposed in an annular shape on the outer circumference of the second eyelet.

7. The third through hole provided in the first eyelet, A fourth through-hole is provided in the second eyelet and communicates with the third through-hole, The second lead inserted into the third through hole and the fourth through hole, It has a second sealing portion that seals the second lead within the third through hole, The semiconductor package stem according to claim 1 or 2, wherein, in a plan view, the opening area of ​​the fourth through-hole is the same as the opening area of ​​the third through-hole.

8. The semiconductor package stem according to claim 7, wherein the wire diameter of the lead is thinner than the wire diameter of the second lead.

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