CN117936483A

CN117936483A - Bonding structure, semiconductor package, and semiconductor device

Info

Publication number: CN117936483A
Application number: CN202410061659.1A
Authority: CN
Inventors: 森隆二; 谷口雅彦
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2017-10-26
Filing date: 2018-09-28
Publication date: 2024-04-26
Also published as: JP6978509B2; WO2019082602A1; CN111316425B; JPWO2019082602A1; CN111316425A

Abstract

Provided are a joint structure, a semiconductor package, and a semiconductor device. The present invention relates to a joint structure or the like in which characteristic impedance matching between a metal terminal and a line conductor is easy. The joint structure (C) and the like are provided with: a metal terminal (1) having an end face (1 a); a line conductor (2) having a side surface (2 a) on which a part of the end surface (1 a) of the metal terminal (1) is opposed; and a bonding material (3) that contains metal particles and is configured to cover from a first end (1 b) containing an end surface (1 a) of the metal terminal (1) to a second end (2 b) containing a side surface (2 a) of the line conductor (2), and to be bonded to the metal terminal (1) and the line conductor (2).

Description

Bonding structure, semiconductor package, and semiconductor device

The present application is a divisional application of an application patent application having a filing date of 2018, 9, 28, 2018800683851 and a name of "bonding structure, semiconductor package, and semiconductor device".

Technical Field

The present invention relates to a joint structure for joining a metal terminal and a line conductor, a semiconductor package, and a semiconductor device.

Background

As a semiconductor package for mounting a semiconductor element such as an optical semiconductor element, a device including a substrate on which the semiconductor element is mounted and a lead terminal (metal terminal) fixed to the substrate is known. The mounting of the semiconductor element on the substrate and the fixation of the lead terminal can be performed via an insulating member such as a dielectric substrate.

In this case, in the semiconductor package, the signal terminals are bonded to the dielectric substrate via a solder such as gold-tin or tin-silver, and fixed. The signal terminals are metal lead terminals and the like. A metal layer is provided in advance at a portion bonded to the solder in the surface of the dielectric substrate. The end portion of the lead terminal is bonded to the metal layer so as to face the metal layer along the longitudinal direction of the lead terminal (see, for example, patent document 1).

Prior art literature

Patent literature

Patent document 1: international publication No. 2017/033860

Disclosure of Invention

Problems to be solved by the invention

In recent years, the frequency of signals transmitted through a transmission path formed of a signal terminal and a metal layer has been increased. Therefore, it is continuously demanded to perform matching of the characteristic impedance in the transmission path with higher accuracy. In addition, there is a continuous demand for a bonding structure in which the structure of such a semiconductor package is easy.

Means for solving the problems

The joint structure according to one embodiment of the present invention includes: a metal terminal having an end face; a line conductor having a side surface on which a part of the end surface of the metal terminal is opposed; and a bonding material that includes metal particles, covers a part of the line conductor from the end surface of the metal terminal, and is bonded to the metal terminal and the line conductor.

A semiconductor package according to an embodiment of the present invention includes: a substrate having a first surface and a second surface opposite to the first surface; a line conductor located on the first surface side of the substrate; a metal terminal penetrating from the second surface to the first surface of the substrate and having an end portion on the first surface side; and a bonding material containing metal particles and existing between the end portion of the metal terminal and the line conductor, wherein the bonding structure has the above structure between the end portion of the metal terminal and the line conductor.

A semiconductor device according to an embodiment of the present invention includes: the semiconductor package having the above structure, and a semiconductor element located on the first surface side and electrically connected to the wiring conductor.

Drawings

The objects, features, and advantages of the present invention will become apparent from the following detailed description and the accompanying drawings.

Fig. 1 is a cross-sectional view showing a joint structure according to an embodiment of the present invention.

Fig. 2A is a perspective view of a semiconductor package according to an embodiment of the present invention.

Fig. 2B is a perspective view from the opposite side of fig. 2A.

Fig. 3A is a top view of a semiconductor package of an embodiment of the present invention.

Fig. 3B is a cross-sectional view taken along line X-X of fig. 3A.

Fig. 4 is a cross-sectional view showing a joint structure according to another embodiment of the present invention.

Fig. 5 is a cross-sectional view showing a joint structure according to another embodiment of the present invention.

Fig. 6 is a cross-sectional view showing a joint structure according to another embodiment of the present invention.

Fig. 7 is a cross-sectional view showing a joint structure according to another embodiment of the present invention.

Fig. 8 is a cross-sectional view showing a joint structure according to another embodiment of the present invention.

Fig. 9 is a perspective view of a semiconductor device according to an embodiment of the present invention.

Fig. 10A is a diagram showing a simulation model.

Fig. 10B is a diagram showing a simulation model.

Fig. 10C is a diagram showing simulation results.

Fig. 10D is a diagram showing simulation results.

Symbol description-

1. Metal terminal

1 A. End face

1 B. First end

2. Circuit conductor

2 A. Side

2B··second end

2Bb upper surface (of line conductor)

Bonding Material

4. Substrate

4 A. First side

4B··second side

4 C.through hole

5.Insulating plate

6. Substituted substrates

7. Grounding terminal

8. Gap

10. Semiconductor package

20 Semiconductor device

100. Semiconductor device

C.a junction structure.

Detailed Description

A joint structure and a semiconductor package according to an embodiment of the present invention will be described with reference to the drawings. Fig. 1 is a cross-sectional view showing a joint structure according to an embodiment of the present invention. Fig. 2A is a perspective view of a semiconductor package according to an embodiment of the present invention, and fig. 2B is a perspective view from the opposite side of fig. 2A. Fig. 3A is a top view of the semiconductor package according to the embodiment of the present invention, and fig. 3B is a cross-sectional view taken along line X-X of fig. 3A.

The joint structure C according to the embodiment of the present invention includes: a metal terminal 1 having an end face 1 a; a line conductor 2 having a side surface 2a opposed to the end surface 1 a; and a bonding material 3 that contains metal particles and is provided so as to cover a portion of the line conductor 2 (for example, the second end 2b that contains the side surface 2 a) from the end surface 1a of the metal terminal 1 and to be bonded to the metal terminal 1 and the line conductor 2. The bonding structure C is used for bonding a metal terminal 1 and a line conductor 2 via a bonding portion 3 in a semiconductor package, for example, which includes: a metal terminal 1 for external connection; a wiring conductor 2 electrically connected to the semiconductor element; and a substrate 4, wherein the metal terminals 1 and the line conductors 2 are arranged in a predetermined positional relationship. The semiconductor package 10 according to the embodiment of the present invention includes: the metal terminal 1, the line conductor 2, the bonding material 3 existing between the metal terminal 1 and the line conductor 2, and the substrate 4 on which the metal terminal 1 and the line conductor 2 are disposed, and the bonding structure C of the above embodiment is provided between the metal terminal 1 and the line conductor 2.

In addition, in the example shown in fig. 2A, 2B, 3A, and 3B, the semiconductor package 10 further has: an insulating plate 5 to which the line conductor 2 is actually arranged and fixed to the substrate 4, and a sub-mount (sub-mount) 6 bonded to the insulating plate 5. The substrate 4 has a first surface 4a and a second surface 4b on the opposite side to the first surface 4a, and a through hole 4c penetrating the substrate 4 in the thickness direction is provided between the first surface 4a and the second surface 4 b. The metal terminal 1 penetrates the substrate 4 from the second surface 4b to the first surface 4a through the through hole 4c. The end face 1a of the metal terminal 1 and the first end 1b including the end face are located on the first face 4a side. The insulating plate 5 is located on the first surface 4a side of the substrate 4, and thus the line conductor 2 is disposed on the first surface 4a side of the substrate 4. On the first surface 4a side of the substrate 4, the metal terminal 1 and the line conductor 2 are bonded to each other via the bonded structure C having the above-described structure. That is, a part of the end surface 1a of the metal terminal 1 faces the side surface 2a of the line conductor 2. The bonding material 3 containing metal particles is provided so as to cover the first end 1b containing the end face 1a of the metal terminal 1 to the second end 2b containing the side face 2a of the line conductor 2. The bonding material 3 bonds the metal terminal 1 and the line conductor 2, and the metal terminal 1 and the line conductor 2 are bonded to each other by the bonding material 3.

The semiconductor package 10 hermetically seals a semiconductor device (not shown) such as an optical semiconductor device, for example. The semiconductor element is mounted on the insulating plate 5 and is electrically connected to the line conductor 2. If the first surface 4a side of the substrate 4 on which the semiconductor element is mounted is sealed with a metal CAN (not shown), a so-called TO (Transistor Outline ) -CAN type semiconductor package is formed. When the semiconductor element is an optical semiconductor element, a metal case having an opening for inputting and outputting an optical signal is used.

In the joint structure C of the embodiment, the metal terminal 1 has a function as a conductive path for external connection of the semiconductor package 10 as described above. In this case, the metal terminal 1 is a lead (lead) terminal in the form of an elongated strip or bar. The metal terminal 1 is made of a metal material such as an alloy material including an iron-nickel-cobalt alloy, an iron-nickel alloy, or copper. When the metal terminal 1 includes an iron-nickel-cobalt alloy, for example, it can be manufactured by subjecting an ingot (block) of the iron-nickel-cobalt alloy to a metal process appropriately selected from rolling, blanking, cutting, etching, and the like.

The metal terminals 1 may be, for example, as in the examples shown in fig. 2A, 2B, 3A, and 3B, a plurality of metal terminals 1 may be fixed to the substrate 4 in parallel. In the example shown in fig. 2A, 2B, 3A, and 3B, a pair of metal terminals 1 for signal transmission are disposed so as to penetrate the substrate 4. Each metal terminal 1 has an end 1a located on the first surface 4a side of the substrate 4, and a first end 1b including an end surface 1 a. The portion (hermetically sealed portion) of the metal terminal 1 located on the first surface 4a side of the substrate 4 can also be regarded as the first end portion 1b.

In the example shown in fig. 2A, 2B, 3A, and 3B, the ground terminal 7 is arranged alongside the pair of metal terminals 1. The ground terminal 7 can be manufactured by the same method using the same metal material as the metal terminal 1. Details of the structure and functions of the metal terminals 1 in the semiconductor package 10 are described later.

The metal terminal 1 is, for example, a wire-like terminal having a length of 1.5 to 22mm and a diameter of 0.1 to 1 mm. In the case of signal transmission, the diameter of each metal terminal 1 is set to 0.15 to 0.25mm in consideration of matching of mechanical strength and characteristic impedance (hereinafter, simply referred to as impedance) of the pair of metal terminals 1, miniaturization as the semiconductor package 10, and the like. When the diameter of the metal terminal 1 is 0.15mm or more, for example, bending of the metal terminal 1 during operation of the semiconductor package 10 is easily suppressed, which is advantageous in improving workability and the like. Further, if the diameter of the metal terminal 1 is 0.25mm or less, the diameter of the through hole 4c through which the metal terminal 1 penetrates can be suppressed to be small, and thus the miniaturization of the substrate 4, that is, the miniaturization of the semiconductor package 10 can be effectively achieved.

The line conductor 2 has a function as a conductor for connecting semiconductor elements of the semiconductor package 10, for example. The semiconductor element and the wiring conductor 2 can be electrically connected via a bonding wire, a low melting point solder such as solder, or the like. In the case of a bonding wire, a bonding wire such as a gold wire or an aluminum wire may be sequentially bonded to the semiconductor element (electrode) and the wiring conductor 2 by a bonding method such as ball bonding (ball bonding). This enables the semiconductor element to be electrically connected to the line conductor 2. The wiring conductor 2 and the metal terminal 1 are bonded to each other via the bonding material 3 to form a conductive path for electrically connecting the semiconductor element to an external circuit.

As described above, the line conductor 2 is formed on the surface of the insulating plate 5, for example. The insulating plate 5 is fixed to the first surface 4a side of the substrate 4, and the line conductor 2 is positioned on the first surface 4a side of the substrate 4. The line conductor 2 has a side face 2a on the first face 4a side and has a second end 2b including the side face 2 a. The end face 1a of the metal terminal 1 is located on the first face 4a side so as to face the side face 2a of the line conductor 2. The end face 1a of the metal terminal 1 may be partially opposed to the side face 2a of the line conductor 2. The first end portion 1b of the metal terminal 1 and the second end portion 2b of the line conductor 2 are bonded to each other via a bonding material 3 described later. The joining material 3 is also joined to the end face 1a and the side face 2 a.

The line conductor 2 is formed of, for example, a metal material appropriately selected from the group consisting of tungsten, molybdenum, manganese, copper, silver, gold, palladium, platinum, rhodium, nickel, cobalt, and the like, or an alloy metal material containing these metal materials. The wiring conductor 2 may be formed in the form of a metallization layer, a plating layer, a thin film layer, or the like. The wiring conductor 2 is formed on the insulating plate 5 as described above, and may further include an adhesion metal layer such as titanium, chromium, tantalum, niobium, nickel-chromium alloy, tantalum nitride, or the like when the film layer includes gold, copper, nickel, silver, or the like. The adhesion metal layer is located between the insulating plate 5 and the thin film layer, and has a function of improving adhesion of the line conductor 2 to the insulating plate 5.

The thickness of the line conductor 2 is set to about 0.1 to 5 μm in consideration of, for example, reduction in resistance, suppression of internal stress, and the like. The thickness of the adhesion metal layer is set to about 0.01 to 0.2 μm in consideration of improvement of adhesion to the insulating plate 5, suppression of internal stress, and the like. The wiring conductor 2 may further include a diffusion suppressing layer between the adhesion metal layer and the thin film layer to suppress mutual diffusion between the two layers. The diffusion suppression layer can be formed of a metal material such as platinum, palladium, rhodium, nickel, or titanium-tungsten alloy. The thickness of the diffusion suppressing layer is set to about 0.05 to 1 μm in consideration of, for example, the suppression of the interdiffusion and the suppression of the resistance of the line conductor 2.

When the line conductor 2 is disposed on the surface of the insulating plate 5 by a metallization method, for example, a metal material suitably selected from tungsten, molybdenum, manganese, copper, silver, gold, platinum, palladium, and the like may be included. In this case, for example, a metal paste prepared by kneading tungsten powder together with an organic solvent, a binder, and the like is fired with the insulating plate 5, whereby the wiring conductor 2 can be formed.

The insulating plate 5 is formed of a ceramic insulating material such as an alumina sintered body, an aluminum nitride sintered body, a silicon nitride sintered body, or a glass ceramic sintered body, for example. When the insulating plate 5 includes an alumina sintered body, for example, it can be produced as follows. First, a slurry is prepared by adding an appropriate organic solvent or solvent to a raw material powder such as alumina, silica, calcium oxide, or magnesium oxide, and mixing the mixture. Next, the slurry is formed into a sheet shape by a doctor blade method, a calender roll method, or the like, to obtain a ceramic green sheet (hereinafter, also referred to as green sheet). Thereafter, the green sheet is die cut into a predetermined shape, and a plurality of sheets are stacked as necessary, and fired at a predetermined temperature of about 1300 to 1600 ℃. Through the above steps, the insulating plate 5 can be manufactured.

When the line conductor 2 includes a metallized layer such as tungsten, a method of manufacturing the insulating board 5 by printing a metal paste for the metallized layer (line conductor 2) in a predetermined pattern on the surface of a green sheet and firing the pattern may be used. In this case, the insulating plate 5 and the line conductor 2 can be integrally manufactured. Therefore, the bonding strength between the line conductor 2 and the insulating plate 5 is effective for improvement of productivity and the like.

The bonding material 3 is provided so as to cover the first end portion 1b including the end face 1a of the metal terminal 1 to the second end portion 2b including the side face 2a of the line conductor 2. The bonding material 3 to be bonded to the first end portion 1b of the metal terminal 1 and the second end portion 2b of the line conductor 2 includes, for example: metal particles containing a metal material such as silver, copper, gold, or palladium, or a metal material such as an alloy containing these metal materials. The metal particles are bonded to each other by metal bonds, and are formed into a shape of the joint portion 3. The metal particles are bonded to the metal components contained in the metal terminals 1 and the line conductors 2, respectively. Thereby, the metal terminal 1 and the line conductor 2 are bonded via the bonding portion 3.

In this joint structure C, for example, in a vertical cross section (longitudinal cross section) as shown in fig. 1, the end face 1a of the metal terminal 1 is perpendicular to the surface 2bb of the line conductor 2. The direction in which the surface 2bb faces is set to be the upper direction and the opposite direction is set to be the lower direction, perpendicular to the surface 2bb of the line conductor 2 on the opposite side from the insulating plate 5. When the first surface 4a is viewed from the first surface 4a side of the substrate 4, a left-right direction opposite to the up-down direction is also defined. The surface 2bb of the line conductor 2 is hereinafter referred to as the upper surface 2bb. The upper surface 2bb of the line conductor 2 constitutes a part of the second end 2b of the line conductor 2. The side surface 2a of the line conductor 2 is substantially parallel to the end surface 1a of the metal terminal 1. Therefore, the end surface of the metal terminal 1 and the side surface of the line conductor 2 can be disposed so as to face each other.

The joint structure C of the metal terminal 1 and the line conductor 2 via the joint material 3 constitutes a signal transmission path between the metal terminal 1 and the line conductor 2, that is, between an external circuit connected to the metal terminal 1 and a semiconductor element connected to the line conductor 2. In this case, in order to cope with a high frequency (for example, 40GHz or more) of a signal transmitted through the transmission path, it is necessary to match the impedance between the metal terminal 1 and the line conductor 2. In contrast, in the joint structure C of the embodiment, it is easy to improve the accuracy of such impedance matching. Details of the improvement in the accuracy of impedance matching are as follows.

That is, according to the joining structure C of the embodiment, the end face 1a of the metal terminal 1 and the side face 2a of the line conductor 2 are joined in a state of facing each other by the joining material 3. That is, in the present invention, the term "opposed to each other" means that the metal terminal 1 and the line conductor 2 do not overlap each other in the direction in which signals are transmitted, that is, in the longitudinal direction of the metal terminal 1. In other words, the metal terminal 1 and the line conductor 2 do not overlap each other in a plan view when viewed in a direction perpendicular to the upper surface 2bb of the line conductor 2. Therefore, the resistance change in the transmission path due to the overlapping of the metal terminal 1 and the line conductor 2 is suppressed. This can reduce the variation in characteristic impedance due to the variation in resistance in the longitudinal direction of the transmission path. Accordingly, the joint structure C can be provided which is effective for improving the accuracy of characteristic impedance matching in the transmission path of the high-frequency signal constituted by the metal terminal 1 and the line conductor 2. In the present embodiment, the end face 1a of the metal terminal 1 faces the side face 2a of the line conductor 2, and the end face 1a is in direct contact with the side face 2 a. In addition, in a cross section including the end face 1a of the metal terminal 1 in the vertical direction, the lower surface of the line conductor 2 is located below the metal terminal 1.

The metal terminal 1 and the line conductor 2 are bonded to each other via the bonding material 3, for example, as follows. First, particles of the metal material (actually, an aggregate of a plurality of particles) such as silver are kneaded together with an organic solvent and a binder to prepare a slurry. Next, the end face 1a of the metal terminal 1 is aligned with the side face 2a of the line conductor 2, and the paste is placed on the aligned portion and temporarily fixed by a jig or the like. After that, they are heated by an electric furnace or the like to bond the metal particles in the slurry to each other. In this case, polymerization or the like between the binder components may also occur. That is, the bonding material 3 may contain the effect of bonding of the polymer based on the organic component in addition to the metal bonds between the metal particles. The temperature of the joining based on the slurry containing the binder component is set to, for example, about 200 to 300 ℃.

By such a behavior of metal particles or the like at the time of bonding, the paste diffuses to the upper surface 2bb of the line conductor 2 at the second end portion 2b and the metal terminal 1. This can produce, for example, a joint structure C as shown in fig. 1.

In this case, if the slurry contains organic components that polymerize with each other, the slurry is cured at a relatively low temperature by the polymer of the organic components, and thus the shape of the slurry to be the joining material 3 is easily maintained. Therefore, the first end portion 1b of the metal terminal 1 and the second end portion 2b of the line conductor 2 can be easily bonded via the bonding material 3. Further, since bonding can be performed at a relatively low temperature, bonding can be performed. The workability of joining the metal terminal 1 and the line conductor 2 via the joining material 3 and the productivity as the joined structure C and the semiconductor package 10 are also improved.

In addition, when considering the ease of bonding between metal particles, the strength of bonding, and the like, the metal particles in the bonding material 3 may be fine particles (so-called submicron particles, sub-nanometer particles, nanometer particles) having a particle diameter of about 1 μm or less than 1 μm, or may be a mixture of fine particles and metal particles in micrometer units. When such fine particles are used as the metal particles, the slurry to be the joining material 3 may contain an organic resin component that can polymerize with each other. Examples of such an organic resin component include polymerizable carboxylic acid derivatives and the like.

Fig. 4 is an enlarged cross-sectional view showing a main portion of a joint structure C according to another embodiment of the present invention. In fig. 4, the same portions as those in fig. 1 to 3B are given the same reference numerals. In the example shown in fig. 4, the end face 1a of the metal terminal 1 is opposed to the side face 2a of the line conductor 2 and is separated from each other. A gap 8 exists between the end face 1a and the side face 2a, and the joining material 3 is located in the gap 8. That is, the end face 1a of the metal terminal 1 which is separated from each other and is not directly connected to the side face 2a of the line conductor 2 are connected to each other by the bonding material 3, and are electrically connected to each other. Otherwise, the joint structure C and the semiconductor package 10 of the other embodiment are the same as the joint structure C and the semiconductor package 10 of the above-described embodiment. Regarding the same points, the description is omitted.

In such a case, it is advantageous to effectively alleviate the thermal stress generated between the metal terminal 1 and the line conductor 2. That is, thermal stress may occur between the metal terminal 1 including the metal material and the line conductor 2 fixed to the insulating plate 5 due to a difference in thermal expansion coefficient between the metal terminal 1 and the insulating plate 5. In this case, the bonding material 3 including a metallic material such as silver, which is relatively easy to deform, is present in an amount (volume) of the gap 8 to be filled, that is, in an amount easy to deform. Therefore, thermal stress generated between the metal terminal 1 and the line conductor 2 (insulating plate 5) can be effectively relaxed by the deformation of the bonding material 3.

In this example, since the thermal stress is relaxed as described above, mechanical breakage of the joined structure C due to the thermal stress can be effectively suppressed. Therefore, in this case, the joint structure C can be provided which is effective for improving the accuracy of impedance matching and is also effective for improving the long-term reliability of the joint between the metal terminal 1 and the line conductor 2. In order to obtain such an effect of improving reliability, the joining material 3 preferably contains a metal material having a relatively small elastic modulus (e.g., young's modulus) such as silver or copper. In the case where the bonding material 3 contains silver or copper, it is also advantageous for the on-resistance in the bonding material 3 to be reduced.

Further, if the joining material 3 contains fine particles of silver or the like as described above, it is easy to (macroscopically) deform the joining material 3 due to displacement of the bonds between the fine particles. Therefore, the bonding material 3 is preferably a fine particle containing silver or copper, for example, for improving the bonding reliability.

Further, if the size of the gap 8 is about 10 μm or more in a plan view (as viewed from a direction facing the upper surface of the line conductor 2), the bonding material 3 can be easily positioned between the end surface 1a and the side surface 2a in an amount effective to alleviate the thermal stress. Further, if the gap 8 is about 100 μm or less in a plan view, for example, the possibility that the distance between the end surface 1a of the metal terminal 1 and the side surface 2a of the line conductor 2 increases to such an extent that the joining material 3 is difficult to enter can be reduced. That is, it is advantageous to ensure workability and bonding strength of the metal terminal 1 and the line conductor 2 via the bonding material 3. Therefore, when the gap 8 is set between the end face 1a of the metal terminal 1 and the side face 2a of the line conductor 2, the size of the gap 8 in a plan view may be set to a range of about 10 to 100 μm.

The manner of including such a gap 8 is not limited to the example shown in fig. 4. For example, the bonding material 3 may be bonded so as to surround the lower surface of the metal terminal 1 from the gap 8, or the bonding material 3 may be formed so as to surround the entire circumference (that is, in a ring shape) of the metal terminal 1 at the first end portion 1b of the metal terminal 1.

In the example shown in fig. 1 and 4, the upper outer periphery of the joining material 3 is slightly expanded to the outside. That is, in the longitudinal section, a part of the outer periphery of the joining material 3 is convex outward. This also increases the amount of the bonding material 3, and improves the effect of reducing the on-resistance and relaxing the stress.

The positional relationship between the metal terminal 1 and the line conductor 2, in which the end face 1a and the side face 2a are joined to face each other, is not limited to the examples shown in fig. 1 to 4. For example, the metal terminal 1 may be located below the line conductor 2, or may be connected to the side surface 2a of the line conductor 2 at the center of the end surface 1 a.

However, for example, as shown in fig. 1 and 4, in the joint structure C in which the metal terminal 1 and the line conductor 2 are parallel to each other in the longitudinal direction, the metal terminal 1 is located above the line conductor 2, and the lower portion of the end surface 1a of the metal terminal 1 and the side surface of the line conductor face each other, there are the following advantages. That is, in this case, the metal terminal 1 can be aligned with the line conductor 2 from the upper side, which is the direction in which the line conductor 2 is exposed, and therefore, the alignment operation is easy, and the positional accuracy is also easy to improve. Therefore, the bonding structure C and the semiconductor package 10 are advantageous in terms of improvement in characteristics and productivity.

In this case, the bonding material 3 is also easily formed in a convex shape that expands outward as described above. Therefore, it is easy to produce the joint structure C having a structure advantageous in improving the effect of stress relaxation.

Fig. 5 is an enlarged cross-sectional view showing a main portion of a joint structure C according to another embodiment of the present invention. In fig. 5, the same portions as those in fig. 1 to 3B are given the same reference numerals. In the example shown in fig. 5, the lower surface of the metal terminal 1 is located below the line conductor 2 in a cross section in the up-down direction including the end surface 1a of the metal terminal 1. Otherwise, the joint structure C and the semiconductor package 10 of the other embodiment are the same as the joint structure C and the semiconductor package 10 of the foregoing embodiment. Regarding the same points, the description is omitted.

In this case, when the side surface 2a of the line conductor 2 is opposed to the end surface 1a of the metal terminal 1, the line conductor 2 can be opposed to the end surface 1a over a relatively wide range. In other words, the severity of alignment of the two can be reduced. Therefore, the bonded structure C and the semiconductor package 10 including the bonded structure C can be manufactured more easily.

In this case, the contact resistance can be reduced by bringing the side surface 2a of the line conductor 2 into direct contact with the end surface 1a of the metal terminal 1. In addition, the manufacturing of such a direct contact (connection) structure can be facilitated as described above. Therefore, the impedance can be easily matched, and the on-resistance can be effectively reduced, so that the bonding structure C and the semiconductor package 10 can be provided that are also effective for securing productivity.

Fig. 6 is an enlarged cross-sectional view showing a main portion of a joint structure C according to another embodiment of the present invention. In fig. 6, the same portions as those in fig. 1 to 3B are given the same reference numerals. In the example shown in fig. 6, the bonding material 3 is provided so as to cover the outer periphery of the metal terminal 1 at the first end portion 1b of the metal terminal 1, except for the structure in which the end surface 1a of the metal terminal 1 is opposed to the side surface 2a of the line conductor 2 and the end surface 1a is in direct contact with the side surface 2a, as in the embodiment shown in fig. 1. Otherwise, the joint structure C and the semiconductor package 10 according to the further embodiment are the same as the joint structure C and the semiconductor package 10 according to the foregoing embodiments. Regarding the same points, the description is omitted.

By the end face 1a being opposed to the side face 2a, a change in resistance in the transmission path due to overlapping of the metal terminal 1 and the line conductor 2 is suppressed. On the other hand, as shown in fig. 1, at the first end portion 1b, a part of the lower portion of the peripheral surface is not covered with the joining material 3, and if there is a portion adjacent to air at the metal terminal 1, the impedance locally changes at that portion. The transmission characteristics of the transmitted signal deteriorate due to reflection or the like caused by the change. In the present embodiment, since the joining material 3 is provided so as to cover the outer periphery of the first end portion 1b, it is possible to suppress the variation in impedance in the first end portion 1b and to suppress the deterioration of the transmission characteristics. The joining material 3 covers the outer periphery of the portion of the first end portion 1b protruding from the first face 4 a. The joining material 3 may also be covered in direct contact with the outer periphery.

Fig. 7 is an enlarged cross-sectional view showing a main portion of a joint structure C according to another embodiment of the present invention. In fig. 7, the same portions as those in fig. 1 to 3B are given the same reference numerals. In the example shown in fig. 7, among the metal terminals 1, only the end face 1a is exposed on the first face 4a side of the substrate 4, and the end face 1a of the metal terminal 1 faces the side face 2a of the line conductor 2, and the end face 1a is in direct contact with the side face 2 a. Otherwise, the joint structure C and the semiconductor package 10 of the other embodiment are the same as the joint structure C and the semiconductor package 10 of the foregoing embodiment. Regarding the same points, the description is omitted. As for the positional relationship in the up-down direction in the present embodiment, as in the embodiment shown in fig. 1, the lower surface of the line conductor 2 is located below the metal terminal 1 in a cross section in the up-down direction including the end surface 1a of the metal terminal 1.

The term "metal terminal 1" means that only the end face 1a is exposed on the first face 4a side of the substrate 4, in other words, the first face 4a is flush with the end face 1a, or the end face 1a does not protrude from the first face 4a when viewed in the longitudinal direction of the metal terminal 1. The bonding material 3 is provided so as to cover the exposed end face 1a to the second end 2b including the side face 2a of the line conductor 2. As will be described later, a sealing material containing an insulating material is located in the through hole 4c of the substrate 4. The seal has a function of blocking the gap between the metal terminal 1 and the through hole 4 c. When only the end face 1a is exposed on the first face 4a side, the peripheral surface of the metal terminal 1 in the through hole 4c of the substrate 4 is covered with the seal over the entire circumference, and the end face 1a is covered with the joining material 3, so that there is no portion in contact with air. Thereby, local variations in impedance are suppressed, and deterioration of transmission characteristics can be suppressed.

Fig. 8 is an enlarged cross-sectional view showing a main portion of a joint structure C according to another embodiment of the present invention. In fig. 8, the same portions as those in fig. 1 to 3B are given the same reference numerals. In the example shown in fig. 8, as in the embodiment shown in fig. 7, only the end face 1a of the metal terminal 1 is exposed on the first face 4a side of the substrate 4, and the end face 1a of the metal terminal 1 faces the side face 2a of the line conductor 2, and the end face 1a is in direct contact with the side face 2 a. As for the positional relationship in the vertical direction, as in the embodiment shown in fig. 5, the lower surface of the metal terminal 1 is located below the line conductor 2 in a section including the end surface 1a of the metal terminal 1 in the vertical direction. Otherwise, the joint structure C and the semiconductor package 10 of the other embodiment are the same as the joint structure C and the semiconductor package 10 of the foregoing embodiment. Regarding the same points, the description is omitted.

In the examples of the above embodiments including the other embodiments, the bonding material 3 may be continuously extended from the first end portion 1b of the metal terminal 1 to the portion where the side surface of the upper surface 2bb of the line conductor 2 is connected. In this case, the bonding material 3 spreads and bonds to the line conductor 2 in a relatively wide range, and therefore, it is effective for improving the bonding strength between the bonding material 3 and the line conductor 2. In addition, the bonding strength between the metal terminal 1 and the line conductor 2 via the bonding material 3 can be effectively improved.

In this case, the tip of the portion where the upper surface 2bb of the line conductor 2 is joined in the joining material 3 may have a shape having no corner portion, such as an arc shape or an elliptical arc shape, in a plan view. In this case, the possibility of peeling of the joining material starting from the corner portion can be effectively reduced. Therefore, the bonding strength between the metal terminal 1 and the line conductor 2 via the bonding material 3 can be effectively improved.

Further, in the above examples, when the metal particles are silver particles, it is advantageous in the following aspects. That is, the heat conductivity of the bonding material 3 (that is, the heat release property of the bonding structure C and the semiconductor package 10 including the same), the reduction of the resistance in the signal transmission path including the line conductor 2 and the metal terminal 1, and the like are advantageous. In addition, there are advantages in that remelting is difficult and exhaust gas is small even in a heat loading step for mounting a semiconductor element, bonding a metal case, or the like.

In this case, the silver particles may contain 99.9 mass% or more of silver, which is called pure silver, and may contain a trace amount of other components such as copper and gold. Further, the metal particles may not be all silver particles, and for example, both silver particles and copper particles may be contained in the metal particles.

Further, when the metal particles are copper particles or contain copper particles, it is advantageous in terms of reducing the possibility of ion migration, improving the economical efficiency, and the like, as compared with the case where all of the metal particles are silver particles.

As described above, the semiconductor package according to the embodiment of the present invention has the following structure. That is, the semiconductor package 10 of the present embodiment includes: a substrate 4 having a first surface 4a and a second surface 4b on the opposite side of the first surface 4 a; a wiring conductor 2 located on the first surface 4a side of the substrate 4; a metal terminal 1 penetrating from the second surface 4b to the first surface 4a of the substrate 4 and having an end portion 1b on the first surface 4a side; and a bonding material 3 containing metal particles and existing between an end portion (first end portion) 1b of the metal terminal 1 and the line conductor 2. The semiconductor package 10 of the present embodiment has the joint structure C having any of the above structures between the end portion 1b of the metal terminal 1 and the line conductor 2.

According to the semiconductor package 10 of the above embodiment, since the joint structure C having any of the above structures is provided, it is possible to provide the semiconductor package 10 which is easy to match impedance in the signal transmission path formed by the metal terminal 1 and the line conductor 2 and is effective for improving the transmission characteristics of the high frequency signal.

The first surface 4a side of the substrate 4 is sealed by the metal case. In the space formed between the substrate 4 and the metal case, the semiconductor element and the end portion 1b of the metal terminal 1 are sealed. In the examples shown in fig. 2A, 2B, 3A, 3B, etc., the seal (no symbol) is located in the through hole 4c of the substrate 4. The seal has a function of blocking the gap between the metal terminal 1 and the through hole 4 c. The sealing member is made of an insulating material such as a glass material or a ceramic material. Examples of such insulating materials include glasses such as borosilicate glass and sodium glass, and materials in which a ceramic filler for adjusting the coefficient of thermal expansion or the relative dielectric constant is added to these glasses. The insulating material can be appropriately selected in consideration of impedance matching (relative permittivity) in the metal terminal 1, reliability of sealing, and the like. In fig. 1, 4 and 5, the seal between the metal terminal 1 and the through hole 4c of the substrate 5 is omitted.

The sub-board 6 is provided on the first surface 4a of the board 4, and has a board mounting surface perpendicular to the first surface 4 a. In the semiconductor package 10, the sub-board 6 has a function of conducting heat generated by the electronic components mounted on the insulating board 5 to the board 4, and the like. That is, the submount 6 has a function as a heat sink for radiating heat to the outside of the semiconductor package 10.

The sub-substrate 6 may be formed integrally with the substrate 4, or may include a cooling member (e.g., a peltier element, etc.). In the case where the sub-substrate 6 is integrally formed with the substrate 4, the sub-substrate 6 is composed of the same metal material as the substrate 4. Thereby, the heat release property of the semiconductor package 10 is effectively ensured.

Fig. 9 is a perspective view of a semiconductor device according to an embodiment of the present invention. The semiconductor device according to the embodiment of the present invention has the following structure. That is, the semiconductor device 100 of the present embodiment includes: a semiconductor package 10, and a semiconductor element 20 located on the first surface 4a side of the substrate 4 and electrically connected to the wiring conductor 2. As described above, the semiconductor element 20 is, for example, an optical semiconductor element or the like. The semiconductor element 20 is mounted on the insulating plate 5, and is electrically connected to the line conductor 2 by a bonding wire, solder, or the like.

According to the semiconductor device 100 of the above embodiment, since the semiconductor package 10 having any of the above configurations is provided, it is possible to provide the semiconductor device 100 in which impedance matching is easy and the transmission characteristics of the high-frequency signal are improved.

The present invention is not limited to the examples of the above embodiments, and various modifications are possible within the scope of the gist of the present invention.

For example, the end surface 1a of the metal terminal 1 need not be exactly perpendicular to the upper surface 2bb of the line conductor 2, but may be slightly inclined (about several degrees) depending on the machining accuracy or the like.

The high-frequency signal characteristics of the joined structure (first structure) according to the embodiment shown in fig. 1 and the joined structure (second structure) according to the embodiment shown in fig. 8 were simulated and compared. The point of difference between the first structure and the second structure is: the first structure is a structure in which the first end portion 1b of the metal terminal 1 protrudes from the first surface 4a of the substrate 4; the second structure is a structure in which the first end portion 1b of the metal terminal 1 protrudes from the first surface 4a of the substrate 4.

Fig. 10A and 10B are diagrams showing simulation models, where fig. 10A shows a first structural model a and fig. 10B shows a second structural model B. In the first structural model a, the first end portion 1b of the metal terminal 1 protrudes 50 μm from the first surface 4a of the substrate 4. The second structural model B has the following structure: the first end portion 1b of the metal terminal 1 does not protrude from the first surface 4a of the substrate 4, and only the end surface 1a is exposed on the first surface 4a side of the substrate 4, which corresponds to the model of the embodiment shown in fig. 8 of the present invention.

Fig. 10C and 10D are diagrams showing simulation results, where fig. 10C shows reflection loss (S11), and fig. 10D shows insertion loss (S21). The reflection loss and insertion loss are calculation results obtained by S parameter analysis. The result of the first structural model a is indicated by a broken line, and the result of the second structural model B is indicated by a solid line. As for the reflection loss, the smaller the value (dB) of the vertical axis (lower side of the graph), the smaller the loss, indicating that the transmission characteristics are good; as for the insertion loss, the closer the value (dB) of the vertical axis is to zero (upper side of the graph), the smaller the loss is, indicating that the transmission characteristics are good. As shown in fig. 10C, the higher the frequency, the larger the difference between the first structural model a and the second structural model B, and the second structural model B shows good characteristics. As shown in fig. 10D, the second structural model B shows generally good characteristics in terms of insertion loss.

The present invention can be embodied in other various forms without departing from its spirit or essential characteristics. The foregoing embodiments are therefore merely illustrative in all respects, the scope of the invention being indicated by the scope of the claims, and not limited in any way by the text of the specification. Further, all modifications and changes falling within the scope of the claims are within the scope of the present invention.

Claims

1. A joint structure is provided with:

A metal terminal having an end face;

A line conductor having a side surface on which a part of the end surface of the metal terminal is opposed; and

And a bonding material including metal particles, disposed so as to cover a part of the line conductor from the end surface of the metal terminal, and bonded to the metal terminal and the line conductor.

2. The joint structure according to claim 1, wherein,

The end face of the metal terminal and the side face of the line conductor are separated from each other.

3. The joint structure according to claim 1 or 2, wherein,

The metal terminals and the line conductors are parallel to each other in a longitudinal direction, and the metal terminals are located above the line conductors, and a lower portion of the end faces of the metal terminals and an upper portion of the side faces of the line conductors are opposed to each other.

4. The joint structure according to claim 3, wherein,

The lower end of the metal terminal is located below the line conductor in a cross section including the end surface of the metal terminal in the vertical direction.

5. The joint structure according to claim 3 or 4, wherein,

The bonding material is continuously provided from the end face of the metal terminal to a portion adjacent to the side face of the upper surface of the line conductor.

6. The joint structure according to any one of claims 1 to 5, wherein,

The bonding material is provided to cover an outer periphery of a first end portion including the end face of the metal terminal.

7. A semiconductor package is provided with:

the joint structure of any one of claims 1 to 6; and

A substrate having a first surface and a second surface opposite to the first surface,

The line conductor is located on the first side of the substrate,

The metal terminal penetrates from the second surface to the first surface of the substrate, and has an end surface on the first surface side.

8. The semiconductor package of claim 7, wherein,

The first face is flush with the end face, or the end face does not protrude from the first face as viewed in the length direction of the metal terminal.

9. A semiconductor device is provided with:

The semiconductor package of claim 7 or 8; and

And a semiconductor element located on the first surface side and electrically connected to the line conductor.