JP2009076499A - Substrate having lead, semiconductor package, and method of manufacturing substrate having lead - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a substrate having a lead, a semiconductor package and a method of manufacturing the substrate having a lead, capable of improving junction strength of the lead while maintaining electric characteristics in a wide band. <P>SOLUTION: The substrate having a lead has: a base substrate 11 on which a rear metallizing section 26 is formed; and the lead 30 that has a junction section 31 joined to the rear metallizing section 26 and an extension section 32 extended from the junction section 31 to separate from the rear metallizing section 26, has a step section 34 as a space formation section for forming a gap between the junction section 31 and the rear metallizing section 26, and is joined to the rear metallizing section 26 by silver solder 20 as a jointing material arranged in the gap. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a substrate with a lead used in, for example, a high-frequency semiconductor package, a semiconductor package, and a method for manufacturing the substrate with a lead, and particularly relates to a method for improving the bonding strength of a lead.

  A microstrip line is known as a transmission line system for a high-frequency semiconductor package. Some of these transmission line systems use metal foil leads (see, for example, Patent Document 1). For example, as shown in FIGS. 10 and 11, a metal lead is joined to a metallized portion formed on the surface of a ceramic substrate by silver brazing. In order to reduce the thickness of a high-frequency semiconductor package, it is necessary to make the ceramic plate thin. However, in order to obtain a desired impedance, the metallization width of the surface is determined according to the thickness of the substrate. Then, the width W of the metallized portion on the surface and the width of the lead are set narrow. For this reason, the area of the joint portion between the silver solder and the lead is reduced, and it becomes difficult to maintain a desired joint strength. Therefore, when the upward tensile force F is generated as shown in FIG. 11, there may be a disadvantage that the lead is peeled off from the end portion side of the joining portion.

In view of this, as shown in FIGS. 12 and 13, the ceramic substrate is formed in a multilayer structure, a notch is provided in the ceramic plate on which the surface metallized part is formed, and the metallized part is formed on the side surface of the notch. However, a technique for improving the bonding strength is provided by storing silver brazing in the notch and forming a meniscus at the end of the bonding site.
JP 2003-51575 A

  However, the above technique has the following problems. In other words, in the above structure, the metallized portion on the side surface is electrically connected to the metallized portion on the surface and is continuously formed. Therefore, electrically, the same as when the stub is extended and formed on the metallized portion on the surface. An effect occurs, and electrical characteristics deteriorate. In particular, this effect becomes significant in the high frequency band.

  Accordingly, an object of the present invention is to provide a leaded substrate, a semiconductor package, and a method for manufacturing the leaded substrate that can improve the bonding strength of the leads while maintaining the electrical characteristics in a wide band.

  A substrate with leads according to an aspect of the present invention includes a substrate having a metallized portion in which a predetermined region is metallized, a bonded portion bonded to the metalized portion, an extended portion extending from the bonded portion and spaced apart from the metalized portion. And a lead that is joined to the metallized portion by a joining material disposed in the gap, the gap forming portion forming a gap between the jointed portion and the metallized portion. It is characterized by.

  In the leaded substrate according to one aspect of the present invention, the gap forming portion has a step surface extending in a direction intersecting with a main surface direction of the substrate, and the step surface is located inside an edge of the metallized portion. A meniscus is formed between the edge of the metallized portion and the step surface by the bonding material in a bonded state in which the leads are bonded to the metallized portion.

  The substrate with leads according to an aspect of the present invention is characterized in that the leads are configured such that the thickness on one side is larger than the thickness on the other side across the gap forming portion.

A substrate with leads according to an embodiment of the present invention is characterized in that a notch portion as the gap forming portion is formed on a surface of the lead to be joined to the metallized portion. Includes a substrate on which a first metallized portion metallized on one main surface is formed, a frame-like frame bonded to one main surface of the substrate, and one of the substrates on the inner side of the frame. A semiconductor device disposed on a main surface; a lid member that is bonded onto the frame and hermetically seals a hollow portion formed inside the frame; and A second metallized portion metallized by being connected to the first metallized portion through a via hole penetrating; and a metal plate joined to the other main surface of the substrate; and joined to the second metallized portion And a gap forming portion that forms a gap between the joint portion and the second metallized portion, and an extension portion that is spaced apart from the second metallized portion and extends from the joint portion. And a lead joined to the second metallized portion by a joining material disposed in the gap.

  According to one embodiment of the present invention, there is provided a method of manufacturing a substrate with leads, the step of disposing a bonding material in a metallized portion where a predetermined region of the substrate is metallized, and a distance between the bonded portion bonded to the metallized portion and the metallized portion. And a lead having a gap forming portion that forms a gap between the joint portion and the metallized portion, and the gap forming portion is located inside the edge of the metalized portion. A step of disposing the bonding material on the bonding material, and the bonding material being melted and solidified by heat treatment in a state where the bonding material is disposed in the gap, thereby bonding the lead and the metallized portion. And a process.

  According to the present invention, the bonding strength of a lead can be improved while maintaining electrical characteristics in a wide band.

  A method of manufacturing a substrate with leads, a semiconductor package, and a substrate with leads according to the first embodiment of the present invention will be described below with reference to FIGS. In each figure, the configuration is schematically shown by appropriately enlarging, reducing, or omitting it. In the figure, arrows X, Y, and Z indicate three orthogonal directions. An arrow Z points along the vertical direction and points to the surface side (the other main surface side).

  As shown in FIG. 1 to FIG. 4, the high-frequency semiconductor package 1 is disposed inside a base substrate 11, a frame 13 bonded to the surface (the main surface on the other side) of the base substrate 11, and the frame 13. A semiconductor device 14, a lid member 16 (shown only in FIGS. 3 and 4) that is joined to the frame 13 with solder and hermetically seals the hollow portion 15 in the inner portion of the frame 13 in a reduced pressure state, and the base substrate 11 And a metal plate 17 joined to the back surface (one main surface) side. The transmission system of the high-frequency semiconductor package 1 is a microstrip line.

The base substrate 11 is made of alumina (AL ₂ O ₃ ), for example, and has a rectangular shape with a thickness t1 of about 0.2 mm to 0.3 mm, for example.

  A frame 13 made of a metal material is joined with a silver solder 20 near the periphery of the surface of the base substrate 11. A semiconductor device 14 is mounted on the surface of the base substrate 11 and inside the frame 13.

  On the surface 21 of the base substrate 11, a surface metallized portion 22 made of, for example, a W sintered body and constituting a predetermined wiring pattern connected to the semiconductor device 14 is formed. The line width W1 of the surface metallized portion 22 is determined according to the characteristic impedance, the dielectric constant of the base substrate 11, and the like, and is configured to be, for example, about 0.3 mm here. A via hole 23 penetrating the base substrate 11 across its front and back is formed at the end position of the surface metallized portion 22 in the vicinity of the periphery of the base substrate 11.

  The back side of the base substrate 11 is covered with a metal plate 17. The metal plate 17 is made of, for example, CuW, CuMo, FeNiCo, or the like, and has a thickness t2 of, for example, about 0.2 mm to 0.25 mm. The metal plate 17 is joined to the back surface of the base substrate 11 by, for example, silver solder 20 made of AgCu eutectic. Has been. The peripheral edge of the metal plate 17 is configured in a rectangular shape having a plurality of notches 25 at predetermined locations corresponding to the vicinity of the via holes 23 of the base substrate 11. Therefore, the peripheral edge portion of the base substrate 11 corresponding to the notch 25 is exposed.

  On the exposed portion of the back surface of the base substrate 11, a back surface metallized portion 26 that forms a predetermined wiring pattern from the end portion on the back surface side of the via hole 23 to the edge of the base substrate is formed. Similar to the front surface metallized portion 22, the back surface metallized portion 26 is made of a W sintered body and has a line width W1 of about 0.3 mm. Leads 30 are joined by silver solder 20 near the tip of the back metallized portion 26.

  Next, the bonding structure of the lead 30 will be described with reference to FIGS. In FIGS. 5 to 7, the rear surface is located on the upper side and the front surface is located on the lower side.

  The lead 30 includes a bonding portion 31 bonded to the back surface metallized portion 26 and an extending portion 32 extending away from the back surface metallized portion 26, and has a stepped portion 34 at the end of the bonding portion 31. Yes.

  The lead 30 is formed, for example, by removing one end in the longitudinal direction of a rod-shaped member having a square cross section made of FeNiCo alloy by half etching, so that the thick portion 35 having a large thickness and the thin portion 36 having a small thickness serve as a gap forming portion. It consists of an elongate member which has integrally through the level | step difference part 34 of this. The line width W2 of the elongated member is about 0.2 mm, and is uniform in the thick portion 35, the step portion 34, and the thin portion 36. The step portion 34 and the thin portion 36 of the elongated member are curved as shown in FIGS. 6 and 7 to form the lead 30. The corner portion of the step portion 34 constitutes a smooth curved surface 38.

  The thickness t3 of the thick portion 35 is configured to be about 0.2 mm. The thick portion 35 extends in the X direction, and the front surface side is joined to the back metallized portion 26 by the silver solder 20.

  The thickness t4 of the thin portion 36 is configured to be about 0.1 mm which is 1/2 of t3. Due to the stepped portion 34, the thin portion 36 is separated from the back surface metallized portion 26 by a predetermined distance d1 in the Z direction. An end portion of the thin portion 36 in the vicinity of the stepped portion 34, that is, a base end portion side is joined to the back metallized portion 26 by the silver brazing 20 to constitute a joined portion 31.

  The distal end side of the thin portion 36 is curved, is spaced apart from the back surface metallized portion 26 toward the back surface side, extends in the surface direction including the X direction or the Y direction, and constitutes an extending portion 32. The tip of the extending portion 32 is connected to a mounting substrate (not shown), whereby the high frequency semiconductor package 1 is mounted.

  The lead 30 has an end edge of a step surface 34a formed in the step portion 34 extending in the Z direction at a predetermined distance indicated by d2 from the end edge 11a of the base substrate 11 and the end edge 26a of the back surface metallization portion 26 in the Y direction. It is arranged to be located in. For example, d2 is about 0.2 mm.

  Accordingly, the lead 30 has an overlap portion 42 that covers the back surface metallized portion 26 in a plane direction including the X direction and the Y direction while being separated from the back surface metallized portion in the Z direction, and the lead 30, the back surface metalized portion 26, and the base substrate. 11 is formed with a gap 43 having dimensions of d1 in the Z direction and d2 in the surface direction.

  In the bonding process between the lead 30 and the back surface metallized portion 26 in the present embodiment, first, the silver solder 20 is disposed on the back surface metallized portion 26 by a printing method or the like, and the joint portion 31 of the lead 30 is further disposed on the silver solder 20. Is placed. At this time, the edge on the front surface side of the step surface 34 a, that is, the lower end portion in the drawing, is disposed inside the predetermined distance d 1 with respect to the edge 26 a of the back surface metallized portion 26. In this state, the silver solder 20 is melted and solidified by heat treatment such as heating and cooling, and the lead 30 and the back metallized portion 26 are joined by the silver solder 20. At this time, a part of the silver solder 20 is accumulated in the gap 43, and between the edge 26a of the back surface metallized portion 26 and the surface side of the corner portion of the step portion 34 of the lead 30, that is, the back surface side portion of the step surface 34a. A meniscus 45 is formed.

  The substrate with leads, the semiconductor package, and the method for manufacturing the substrate with leads according to the present embodiment have the following effects. That is, the step 30 is provided in the lead 30 and is offset by a predetermined distance d2 from the back metallized portion 26 and the end of the base substrate 11, so that a gap 43 in which the silver solder 20 accumulates is formed, and the silver solder 20 is joined at the time of joining. Since a larger meniscus 45 is formed, the bonding strength can be improved. Further, since the step portion 34 is provided on the lead 30 side, the length of the back surface metallized portion 26 itself can be maintained, and an electrical influence can be avoided. Since a step is provided on the lead 30 side, manufacturing is easier than using a multi-layer substrate and providing a step on the substrate side. Further, since the entire extending portion 32 is made thin, it is strong against bending, and high strength can be secured even when hard plating is applied.

  In addition, this invention is not limited to the said embodiment as it is. For example, in the above embodiment, the stepped portion 34 is provided as the gap forming portion and the entire extending portion 32 on one end side of the lead is thinly formed. However, as shown in FIG. You may comprise the clearance gap spaced apart from the back surface metallization part 26 in a notch part. Moreover, in the said embodiment, although the level | step-difference part 34 was formed in the lead by half etching, you may form by a press process etc. Further, the present invention is also applicable to the case where the corner portion of the step portion 34 is not a smooth curved surface as shown in FIG. Although the case where the lead 30 is bonded to the back surface metallized portion 26 is illustrated, the present invention is not limited to this, and the present invention can also be applied to the front surface metalized portion 22.

  In addition, in the implementation stage, the constituent elements can be modified and embodied without departing from the spirit of the invention. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.

The top view which shows the high frequency semiconductor package concerning one Embodiment of this invention. The bottom view of the high frequency semiconductor package. The front view of the high frequency semiconductor package. The side view of the high frequency semiconductor package. The perspective view which expands and shows the A section of FIG. The side view which expands and shows the B section of FIG. The perspective view which shows the structure of the lead | read | reed concerning one Embodiment of this invention. The side view which shows the junction part concerning other embodiment. The side view which shows the junction part concerning other embodiment. The perspective view which shows an example of a junction part. The side view which shows an example of a junction part. The perspective view which shows an example of a junction part. The side view which shows an example of a junction part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... High frequency semiconductor package, 11 ... Base substrate, 11a ... Edge, 13 ... Frame, 14 ... Semiconductor device, 15 ... Hollow part, 16 ... Lid member, 17 ... Metal plate, 20 ... Silver brazing, 21 ... Surface, 22 ... front surface metallized part (first metallized part), 23 ... via hole, 25 ... notch part, 26 ... back metallized part (second metallized part), 26a ... edge, 30 ... lead, 31 ... joint part, 32 ... extension Protruding part 34 ... Step part 34a ... Step surface 35 ... Thick part 36 ... Thin part 38 ... Curved surface 42 ... Overlap part 43 ... Gap 45 ... Menicus

Claims (6)

A substrate having a metallized portion in which a predetermined region is metallized;
A joining portion joined to the metallized portion and an extending portion extending from the joining portion and spaced apart from the metallized portion; and a gap forming portion for forming a gap between the metallized portion and the joining portion. And a lead bonded to the metallized portion by a bonding material disposed in the gap. The gap forming portion has a step surface extending in a direction intersecting with the main surface direction of the substrate,
The step surface is disposed inside the edge of the metallized portion,
2. The substrate with leads according to claim 1, wherein a meniscus is formed between an edge of the metallized portion and the stepped surface by the bonding material in a bonded state in which the lead is bonded to the metallized portion. .   3. The substrate with leads according to claim 1, wherein the lead is configured such that a thickness on one side is larger than a thickness on the other side across the gap forming portion.   The substrate with leads according to claim 1, wherein a notch portion as the gap forming portion is formed on a surface of the lead to be joined to the metallized portion. A substrate on which a first metallized portion metallized on one main surface is formed;
A frame-like frame joined to one main surface of the substrate;
A semiconductor device disposed on one main surface of the substrate inside the frame; and
A lid member that is bonded onto the frame and hermetically seals a hollow portion formed inside the frame;
A second metallized portion metallized on the other main surface of the substrate connected to the first metallized portion via a via hole penetrating the substrate;
A metal plate joined to the other principal surface of the substrate;
With
A bonding portion bonded to the second metallized portion and an extending portion extending from the bonding portion apart from the second metallized portion; and a gap between the bonding portion and the second metallized portion. A lead that is bonded to the second metallized portion by a bonding material disposed in the gap,
A semiconductor package comprising: Placing the bonding material on the metallized portion where the predetermined region of the substrate is metallized;
A lead having a gap forming portion for forming a gap between the joint portion and the metallized portion, the joint portion being joined to the metallized portion and an extending portion extending away from the metallized portion. A step of disposing on the bonding material such that the gap forming portion is located inside the edge of the metallized portion;
A step of melting and solidifying the bonding material by heat treatment in a state where the bonding material is disposed in the gap, and bonding the lead and the metallized portion;
A method for manufacturing a substrate with leads, comprising:

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