JP6927829B2 - Bonded structure and semiconductor package - Google Patents

Description

The present invention relates to a bonding structure and a semiconductor package including a bonding material interposed between a metal terminal and a line conductor.

As a semiconductor package on which a semiconductor element such as an optical semiconductor element is mounted, a package including a substrate on which the semiconductor element is mounted and a metal terminal fixed to the substrate is known. The mounting of the semiconductor element on the substrate and the fixing of the metal terminal are performed, for example, via an insulating member such as a dielectric substrate.

In this case, in the semiconductor package, the signal terminals are joined and fixed to the dielectric substrate via a brazing material such as gold-tin or tin-silver. The signal terminal is a metal lead pin terminal or the like. A metal layer is provided in advance on the surface of the dielectric substrate to which the brazing material is bonded (see, for example, Patent Document 1).

International Publication No. 2017/033860 Japanese Unexamined Patent Publication No. 9-330949

In a semiconductor package, it is required to improve the reliability of electrical and mechanical connection between a signal terminal and a substrate such as a dielectric substrate. Further, a joining structure effective for improving such connection reliability is required.

The joining structure of one aspect of the present invention joins a metal terminal having an end portion, a line conductor in which the end portion of the metal terminal is located, and the end portion of the metal terminal and the line conductor. It has a joint that is Further, the joint portion contains metal particles, and is between the metal particles and the metal particles with the first joint material including a portion located between the end portion of the metal terminal and the line conductor. It contains a gap located, and has a second joint material interposed between the first joint material and the line conductor, and the first joint material has a gap located between the metal particles. Further included, the proportion of the voids in the second bonding material is larger than the proportion of the voids in the first bonding material .

The semiconductor package according to one aspect 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, and the substrate. It penetrates from the second surface to the first surface, has a metal terminal having an end on the first surface side, contains metal particles, and has the end of the metal terminal and the line conductor. It is equipped with a bonding material that is interposed between the and. Further, it has a bonding structure having the above configuration between the end portion of the metal terminal and the line conductor.

According to the bonding structure of one aspect of the present invention, the possibility of mechanical destruction of the bonding structure due to thermal stress, such as cracks in the bonding material, can be reduced.

According to the semiconductor package of one aspect of the present invention, since it has the bonding structure having the above configuration, it is possible to provide a semiconductor package having high mechanical and electrical connection reliability between the metal terminal and the signal line.

It is sectional drawing which shows the junction structure of embodiment of this invention. It is sectional drawing which shows the A part of FIG. 1 enlarged. It is sectional drawing which shows the modification of FIG. (A) is a perspective view of the semiconductor package according to the embodiment of the present invention, and (b) is a perspective view seen from the opposite side of (a). (A) is a plan view of the semiconductor package according to the embodiment of the present invention, and (b) is a cross-sectional view taken along line XX of (a). It is sectional drawing which shows the main part in the joint structure of another embodiment of this invention in an enlarged manner. It is sectional drawing which shows the bonding structure of another embodiment of this invention.

The bonded structure and the semiconductor package of the embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view showing a joint structure according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing an enlarged portion A of FIG. 1, and FIG. 3 is a cross-sectional view showing a modified example of FIG. It is a figure. Further, FIG. 4A is a perspective view of the semiconductor package according to the embodiment of the present invention, and FIG. 4B is a perspective view seen from the opposite side of FIG. 4A. 5 (a) is a plan view of the semiconductor package according to the embodiment of the present invention, and FIG. 5 (b) is a cross-sectional view taken along the line XX of FIG. 5 (a).

The joining structure C of the embodiment of the present invention has a metal terminal 1 having an end portion 1a, a line conductor 2, and a joining portion 3 for joining the end portion 1a of the metal terminal 1 and the line conductor 2. ing. In the joint portion 3, the end portion 1a of the metal terminal 1 and the line conductor 2 are thus joined to each other. The joint portion 3 contains metal particles, and includes a first joint material 3a including a portion located between the end portion 1a of the metal terminal 1 and the line conductor 2, and the metal particles and voids located in the metal particles. It contains 4a and has a second bonding material 3b interposed between the first bonding material 3a and the line conductor 2. When the joint portion 3 is conductive, the metal terminal 1 and the line conductor 2 are mechanically and electrically connected to each other via the joint portion 3. The end portion 1a of the metal terminal 1 is the tip end of the metal terminal 1 and a portion close to the tip end, and is, for example, a portion located on the first surface 5a side of the substrate 5 in the semiconductor package described later.

The bonding structure C includes, for example, a metal terminal 1 for external connection, a line conductor 2 electrically connected to a semiconductor element, and a substrate 5 in which the metal terminal 1 and the line conductor 2 are arranged in a predetermined positional relationship. It is used for joining a metal terminal 1 and a line conductor 2 via a joining portion 3 in a semiconductor package. In the semiconductor package 10 of the embodiment of the present invention, the metal terminal 1, the line conductor 2, the joint portion 3 interposed between the metal terminal 1 and the line conductor 2, the metal terminal 1 and the line conductor 2 are arranged. Further, it has the bonding structure C of the above-described embodiment between the metal terminal 1 and the line conductor 2.

Further, in the examples shown in FIGS. 4 and 5, the semiconductor package 10 further includes an insulating plate 6 in which the line conductor 2 is actually arranged and fixed to the substrate 5, and a submount bonded to the insulating plate 6. Has 7 and. The substrate 5 has a first surface 5a and a second surface 5b opposite to the first surface, and has a through hole 5c that penetrates the substrate 5 in the thickness direction between the first surface 5a and the second surface 5b. have. The metal terminal 1 penetrates the substrate 5 from the second surface 5b to the first surface 5a through the through hole 5c. The end portion 1a of the metal terminal 1 is located on the first surface 5a side. The insulating plate 6 is located on the first surface 5a side of the substrate 5, so that the line conductor 2 is arranged on the first surface 5a side of the substrate 5. On the first surface 5a side of the substrate 5, the end portion 1a of the metal terminal 1 and the line conductor 2 are joined to each other via the joining structure C having the above configuration.

The semiconductor package 10 airtightly seals a semiconductor element (not shown) such as an optical semiconductor element. The semiconductor element is mounted on the insulating plate 6 and electrically connected to the line conductor 2. If the first surface 5a side of the substrate 5 on which the semiconductor element is mounted is sealed with a metal case (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 input / output of an optical signal is used.

In the bonding structure C of the embodiment, the metal terminal 1 has a function as a conductive path for external connection in the semiconductor package 10 as described above, for example. In this case, the metal terminal 1 is an elongated strip-shaped or rod-shaped lead (pin) terminal. The metal terminal 1 is made of, for example, a metal material such as an iron-nickel-cobalt alloy, an iron-nickel alloy, or an alloy material containing copper. When the metal terminal 1 is made of, for example, an iron-nickel-cobalt alloy, the ingot (lump) of the iron-nickel-cobalt alloy is subjected to metal processing appropriately selected from rolling, punching, cutting, etching and the like. Can be manufactured by.

The metal terminal 1 may be one in which a plurality of metal terminals 1 are arranged side by side and fixed to the substrate 5, as in the examples shown in FIGS. 4 and 5, for example. In the examples shown in FIGS. 4 and 5, a pair of metal terminals 1 for signal transmission are arranged so as to penetrate the substrate 5. Each metal terminal 1 has an end portion 1a located on the first surface 5a side of the substrate 5.

In the examples shown in FIGS. 4 and 5, the ground terminal 8 is arranged alongside the pair of metal terminals 1. The ground terminal 8 can be manufactured by the same method using the same metal material as the metal terminal 1. Details of the configurations and functions of the metal terminal 1 and the ground terminal 8 in the semiconductor package 10 will be described later.

The metal terminal 1 is, for example, linear with a length of 1.5 to 22 mm and a diameter of 0.1 to 1 mm. For signal transmission, the diameter of each metal terminal 1 is 0.15, considering the mechanical strength of the pair of metal terminals 1, matching of characteristic impedance (hereinafter, simply referred to as impedance), and miniaturization of the semiconductor package 10. It shall be ~ 0.25 mm. When the diameter of the metal terminal 1 is 0.15 mm or more, for example, it is easy to suppress bending of the metal terminal 1 when handling the semiconductor package 10, which is advantageous in improving workability and the like. Further, if the diameter of the metal terminal 1 is 0.25 mm or less, the diameter of the through hole 5c through which the metal terminal 1 penetrates can be suppressed to be small, so that the substrate 5 can be downsized, that is, the semiconductor package 10 can be downsized. Is effective.

The line conductor 2 has a function as, for example, a conductor for connecting semiconductor elements in the semiconductor package 10. The electrical connection between the semiconductor element and the line conductor 2 is made via a low melting point brazing material such as a bonding wire or solder. In the case of a bonding wire, the semiconductor element is bonded to the line conductor 2 by sequentially bonding a bonding wire such as a gold wire or an aluminum wire to the semiconductor element (electrode) and the line conductor 2 by a bonding method such as a ball bond method. Can be electrically connected to. The line conductor 2 and the metal terminal 1 are joined to each other via a joint portion 3 to form a conductive path that electrically connects the semiconductor element and the external electric circuit.

As described above, the line conductor 2 is formed on the surface of the insulating plate 6, for example. The insulating plate 6 is fixed to the first surface 5a side of the substrate 5, and the line conductor 2 is located on the first surface 5a side of the substrate 5. On the first surface 5a side, the end portion 1a of the metal terminal 1 is located on the line conductor 2, and both are joined to each other via a joining portion 3 described later.

The line conductor 2 is a metal material appropriately selected from metal materials such as tungsten, molybdenum, manganese, copper, silver, gold, palladium, platinum, rhodium, nickel and cobalt, or a metal material of an alloy containing these metal materials. Is formed by. The line conductor 2 can be formed in the form of a metallized layer, a plating layer, a thin film layer, or the like. The line conductor 2 is formed on the insulating plate 6 as described above, and when it contains a thin layer of gold, copper, nickel, silver or the like, titanium, chromium, tantalum, niobium, nickel-chromium alloy, nitrided. It may further include an adhesive metal layer such as tantalum. The close contact metal layer is located between the insulating plate 6 and the thin film layer, and has a function of improving the adhesion of the line conductor 2 to the insulating plate 6.

The thickness of the line conductor 2 is 0.1 in consideration of, for example, reduction of electrical resistance and suppression of internal stress.
It is set to about 5 μm. The thickness of the adhesive metal layer is set to about 0.01 to 0.2 μm in consideration of improving the adhesiveness to the insulating plate 6 and suppressing internal stress. The line conductor 2 may further include a diffusion suppression layer that suppresses mutual diffusion between the close contact metal layer and the thin film layer. The diffusion suppression layer can be formed of, for example, a metal material such as platinum, palladium, rhodium, nickel, or a titanium-tungsten alloy. The thickness of the diffusion suppression layer is set to about 0.05 to 1 μm in consideration of, for example, the suppression of mutual diffusion and the suppression of electrical resistance in the line conductor 2.

Further, when the line conductor 2 is arranged on the surface of the insulating plate 6 by the metallization method, it is appropriately selected from metal materials such as tungsten, molybdenum, manganese, copper, silver, gold, platinum and palladium. It may contain a metallic material. In this case, for example, the line conductor 2 can be formed by firing a metal paste prepared by kneading tungsten powder with an organic solvent, a binder, or the like with an insulating plate 6.

The insulating plate 6 is formed of, for example, a ceramic insulating material such as an aluminum oxide-based sintered body, an aluminum nitride-based sintered body, a silicon nitride-based sintered body, or a glass-ceramic sintered body. The insulating plate 6 can be manufactured as follows, for example, when it is made of an aluminum oxide sintered body. First, an appropriate organic solvent and solvent are added and mixed with raw material powders such as aluminum oxide, silicon oxide, calcium oxide and magnesium oxide to prepare a slurry. Next, the slurry is formed into a sheet by a doctor blade method, a calendar roll method, or the like to obtain a ceramic green sheet (hereinafter, also referred to as a green sheet). After that, the green sheet is punched into a predetermined shape, and if necessary, a plurality of green sheets are laminated and fired at a predetermined temperature of about 1300 to 1600 ° C. The insulating plate 6 can be manufactured by the above steps.

When the line conductor 2 is made of a metallized layer such as tungsten, a manufacturing method is used in which a metal paste for the metallized layer (line conductor 2) is printed on the surface of a green sheet to be an insulating plate 6 in a predetermined pattern and simultaneously fired. You may. In this case, the insulating plate 6 and the line conductor 2 can be integrally manufactured. Therefore, it is effective in improving the strength and productivity of the joint between the line conductor 2 and the insulating plate 6.

The joint portion 3 interposed between the end portion 1a of the metal terminal 1 and the line conductor 2 is made of, for example, a metal material such as silver, copper, gold and palladium, or a metal material such as an alloy containing these metal materials. Contains metal particles. The metal particles are bonded to each other by metal bonding to form a unified shape as a joint portion 3. Further, the metal particles are bonded to each other with the metal components contained in the metal terminal 1 and the line conductor 2, respectively. As a result, the metal terminal 1 and the line conductor 2 are joined via the joint portion 3. In addition, in FIG. 2 and FIG. 3, the portion where a large number of metal particles are gathered is shown as a columnar portion (columnar portion 4b). Further, the first joining material 3a and the second joining material 3b may be formed of the above-mentioned metal materials having the same composition as each other. In this case, the presence of the voids 4a characterizes the configuration of the second bonding material 3b.

Of the joints 3, the first joint 3a has a function of ensuring mechanical strength, bondability, and conductivity as the joint 3 that mechanically and electrically connects the metal terminal 1 and the line conductor 2. doing. That is, the first joining material 3a can be regarded as a bulk portion or a main body portion of the joining portion 3. The voids 4a exist as a plurality of columnar spaces between the columnar portions 4b. Each of the voids 4a is located so as to extend from the line conductor 2 to the first joining member 3a.

Further, the second joining material 3b has a function of firmly joining the first joining material 3a to the line conductor 2 and relaxing stress such as thermal stress. That is, the gap 4a of the second bonding material 3b absorbs and relaxes the thermal stress generated between, for example, the metal terminal 1 and the bonding portion 3. Since the gap 4a is located along the joint interface between the end portion 1a of the metal terminal 1 and the joint portion 3, the surface portion of the joint portion 3 can be easily deformed in the gap 4a. By this deformation, for example, the thermal stress generated between the insulating plate 6 which is the base on which the line conductor 2 or the line conductor 2 is located and the metal terminal 1 can be absorbed and relaxed. Therefore, the possibility of mechanical destruction of the joint structure C due to thermal stress, such as a crack in the joint portion 3, can be reduced. That is, it is possible to provide a highly reliable joint structure C for electrical and mechanical connection between the metal terminal 1 and the line conductor 2.

The void 4a exists in an area ratio of about 30 to 70% of the joining interface where the line conductor 2 and the second joining member 3b of the joining portion 3 are in contact with each other in consideration of the relaxation of the thermal stress. In other words, the second joining material 3b of the joining portion 3 does not have to be actually joined to the line conductor 2 in an area of about 30 to 70% of the surface facing the line conductor 2. In other words, the second joining material 3b may be actually joined within a range of about 30 to 70% of the surface facing the line conductor 2. When the area ratio of the void 4a portion is about 30% or more, the thermal stress can be effectively absorbed and relaxed. Further, when the area ratio is 70% or less, the actual joint area of the joint portion 3 (second joint material 3b) with respect to the line conductor 2 can be increased to effectively improve the joint strength between the two. can.

Further, the second bonding material 3b containing the voids 4a as described above may contain about 20 to 60% of the voids 4a as a volume ratio. As a result, it becomes easy to position the void 4a at an area ratio of about 30 to 70% of the joining interface where the line conductor 2 and the second joining member 3b of the joining portion 3 are in contact with each other. The thickness of the second bonding material 3b may be, for example, about 1 to 50 μm. Further, the thickness of the second joint member 3b in the thickness of the entire joint portion 3 (the dimension of the joint portion 3 located between the line conductor 2 facing each other and the end portion 1a of the metal terminal 1) is, for example, It may be about 5 to 20%.

The ratio of the voids 4a in the joint portion 3 of the second bonding material 3b or the like can be measured, for example, as the ratio of the voids 4a existing in a certain area by observing the cross section of the joint portion 3. Further, the ratio of the voids 4a of the joint portion 3 can also be known by measuring the porosity or the void ratio. Specific examples thereof include a C1 scanning method using image processing and analysis software, an immersion method in which the void 4a is saturated with a liquid, and the volume of the liquid entering the void 4a is measured. As will be described later, even when the first joining material 3a contains the voids 4a, the proportion of the voids 4a can be measured by various methods as described above.

In the examples of FIGS. 3 and 4, the voids 4a such as columns are located between the columnar portions 4b formed by bonding a large number of metal particles to each other, but the voids 4a are not limited to this form. For example, the void 4a having an elliptical shape or an indefinite shape having a smaller area in cross-sectional view may be used. In this case, the gap 4a includes both those located so as to be in contact with the line conductor 2 or the first joining material 3a and those existing as a closed space inside the second joining material 3b. It may also contain only one of them.

Further, the dimension of the void 4a (distance between the surfaces of the columnar portions 4b facing each other across the void 4a) is as small as about 1 μm in consideration of suppressing the entry of corrosive components such as water into the void 4a. It should be.

For the dimensions of the void 4a, conditions such as the particle size of the metal particles, the joining conditions such as the heating temperature at the time of joining, the material of the metal particles, and the magnitude and direction of the external force such as gravity acting on the joining portion 3 at the time of joining are appropriately adjusted. do it. For example, if it is desired to increase the relaxation of the thermal stress on the insulating plate 6, the dimension of the gap 4a may be increased to improve the heat transfer property through the joint portion 3 between the line conductor 2 and the metal terminal 1.

The metal terminal 1 and the line conductor 2 are joined via the joint portion 3 as follows, for example. First, particles of the above metal material such as silver (actually, an aggregate of a large number of particles) are kneaded together with an organic solvent and a binder to prepare a paste. Next, the end portion 1a of the metal terminal 1 is aligned with a predetermined portion of the line conductor 2 with this paste sandwiched between them, and temporarily fixed with a jig or the like. Then, these are heated in an electric furnace or the like to sinter the metal particles in the paste. At this time, polymerization or the like may occur between the binder components. That is, the bonding portion 3 may include a bonding action by a polymer of an organic component in addition to the metal bonding between the metal particles. The temperature of joining with the paste containing the binder component is set to, for example, about 200 to 300 ° C.

Further, the metal particles in the bonding portion 3 are fine particles having a particle size of about 1 μm or less (so-called submicron particles, sub-nano particles, etc.) in consideration of the ease of bonding between the metal particles, the strength of bonding, and the like. It may be a nanoparticle) or a mixture of microparticles and micron-sized metal particles. The paste to be the joint portion 3 may contain an organic resin component that polymerizes with each other when such fine particles are used as metal particles. Examples of such an organic resin component include a polymerizable carboxylic acid derivative and the like.

Further, the bonding portion 3 does not have to contain metal particles which are fine particles, and may be a polycrystalline body containing crystal particles such as silver or copper as metal particles. Also in this case, the void 4a can be generated by a method such as increasing the content of the organic component in the paste relatively.

In the joint structure C of the embodiment, for example, as shown in FIG. 3, the joint portion 3 may further have a third joint material 3c. The third bonding material 3c is mainly composed of the same metal material as the metal particles described above, and is composed of a thin layer (unsigned as a thin layer) located along the surface of the line conductor 2. In the third bonding material 3c, the main component metal material is contained, for example, about 80% by mass or more.

This thin layer (third joint material 3c) includes a portion interposed between the second joint material 3b and the line conductor 2. FIG. 3 shows an example in which the third joining material 3c is located along the entire surface of the joining interface between the line conductor 2 and the second joining material 3b. The third bonding material 3c contains, for example, the same metal material (for example, palladium, tungsten, platinum, titanium, etc.) contained in the line conductor 2 in addition to the same metal material as the metal particles as the main component. It may have the same composition as that of the second bonding material 3b.

The thin layer forming the third bonding material 3c is, for example, a metal layer having a thickness of about 0.1 to 10 μm. The presence of such a thin layer at the joint portion 3 can effectively reduce the possibility of corrosion of the line conductor 2 due to the adhesion of moisture.

The thin layer can be formed, for example, by adjusting the heating temperature and time at the time of joining the metal terminal 1 and the line conductor 2 via the joint portion 3 (paste described above). For example, the above-mentioned joining temperature may be set to about the upper limit (300 ° C., etc.) of the joining temperature of the paste serving as the joining portion 3 so that the metal terminal 1 and the line conductor 2 are joined. Due to the heat at this time, components such as silver in the joint portion 3 wet and spread along the surface of the end portion 1a of the metal terminal 1 to form a thin layer.

Further, in the example shown in FIG. 3, the diffusion layer 9 is located at the interface portion between the third bonding material 3c and the line conductor 2. The diffusion layer 9 contains both the components of the third bonding material 3c and the line conductor 2. That is, the diffusion layer 9 includes one or more kinds of metal materials such as tungsten, molybdenum, manganese, copper, silver, gold, palladium, platinum, rhodium, nickel and cobalt forming the line conductor 2, and a third kind. It contains one or more metal materials such as silver, copper, gold and palladium forming the bonding material 3c (metal particles and the like).

The diffusion layer 9 includes, for example, the metal material of the line conductor 2 and the metal material of the third bonding material 3c that are in contact with each other due to the heat applied at the time of joining the line conductor 2 and the metal terminal 1 via the bonding material 3. Is generated by mutual diffusion. Further, the diffusion layer 9 may be formed by diffusing a metal material having a relatively low melting point such as silver or copper into a metal material having a relatively high melting point such as tungsten, palladium or platinum. ..

The presence of the diffusion layer 9 containing both components together between the line conductor 2 and the third joint material 3c of the joint portion 3 causes the line conductor 2 and the third joint material 3c to be separated from each other. Effectively improves joint strength. Thereby, the joint strength between the line conductor 2 and the joint portion 3 and the metal terminal 1 can be improved. Therefore, the junction structure C suitable for manufacturing the semiconductor package 10 which is advantageous for improving the electrical connection reliability between the semiconductor element and the external electric circuit via the metal terminal 1 can be obtained.

Further, in the example shown in FIG. 3, the first bonding material 3a further includes a void 4a interposed between the metal particles. Further, in this case, the ratio of the voids 4a in the second joint material 3b is larger than the ratio of the voids 4a in the first joint material 3a. In this case, the relatively large proportion of the voids 4a present characterizes the configuration of the second bonding material 3b with respect to the first bonding material 3a. In this case, the volume ratio of the void 4a in the first bonding material 3a is, for example, about 1 to 30%, and the volume ratio of the void 4a in the second bonding material 3b (about 20 to 60% described above, etc.). Set to a value smaller than.

In each of the above examples, the second joining material 3b is located in a region of the line conductor 2 facing the metal terminal 1 via the joining portion 3 (hereinafter, also referred to as an facing region). That is, the gap 4a contained in the second joint material 3b is located at the joint portion of the line conductor 2 and the metal terminal 1 via the joint portion 3. When the second bonding material 3b (that is, the gap 4a) is located in the facing region, the thermal stress can be effectively relaxed in the facing region where the thermal stress is likely to be concentrated in the line conductor 2 and the joint portion 3. can. Therefore, the joint structure C can be obtained, which is particularly advantageous for relaxing thermal stress and is effective for improving reliability.

In order to position the second bonding material 3b containing the voids 4a in the opposite region, for example, the viscosity of the paste to be the bonding portion 3, the type and content of components such as an organic binder, the bonding temperature, the heating time at the time of bonding, and The type of metal material contained in the line conductor 2 may be adjusted so that the metal particles are bonded to the shape of the columnar portion 4b or the like at a position away from the line conductor 2. For example, if an organic binder having a relatively low polymerization start temperature is used, the paste tends to solidify at the initial stage of joining, so that bonds between metal particles are likely to occur in the bulk of the paste, and the paste and the line conductor 2 Bonds between metal particles are unlikely to occur near the interface of. Therefore, the portion where the bond between the metal particles is likely to occur is the first bonding material 3a, and the portion where the bond between the metal particles is unlikely to occur is the second bonding material 3b. As a result, for example, a joint portion 3 having a form as shown in FIG. 3 is formed, and a joint structure including the joint portion 3 is formed.

Further, in each of the above examples, when the metal particles are silver particles, it is advantageous in the following points. That is, it is advantageous for thermal conductivity at the junction 3 (that is, heat dissipation of the junction structure C and the semiconductor package 10 including the junction structure C), reduction of electrical resistance in the signal transmission line including the line conductor 2 and the metal terminal 1, and the like. be. Further, there is an advantage that it is difficult to remelt even in a heat load process for mounting a semiconductor element or joining a metal case, and there is little outgassing.

The silver particles in this case may be so-called sterling silver containing 99.9% by mass or more of silver, or may contain a trace amount of other components such as copper or gold. Further, not all of the metal particles need to be silver particles, and for example, both silver particles and copper particles may be contained in the metal particles.

When the metal particles are copper particles or contain copper particles, the possibility of ion migration is reduced, the economic efficiency is improved, etc., as compared with the case where all the metal particles are silver particles. Is advantageous.

In each example of the above embodiment, the joining structure C may further include an auxiliary joining portion 3A interposed between the first joining member 3a and the metal terminal 1 (particularly the end portion 1a). The auxiliary joint portion 3A has the same composition as any of the second joint material 3b and the third joint material 3c. In the example shown in FIG. 6, between the first joint material 3a of the joint portion 3 and the metal terminal 1, the auxiliary second joint material 3bb having the same composition as the second joint material 3b and the same as the third joint material 3c. Both with the auxiliary third bonding material 3cc of the composition of are located. That is, the auxiliary joint portion 3A in this example has an auxiliary second joint material 3bb and an auxiliary third joint material 3cc. FIG. 6 is an enlarged cross-sectional view showing a main part of the joint structure C and the semiconductor package 10 in the joint structure of another embodiment of the present invention. In FIG. 6, the same parts as those in FIGS. 1 to 5 are designated by the same reference numerals.

The "same composition" in this case is not limited to a configuration in which the types and contents of the metal materials are the same, and the configuration including the voids 4a and the columnar portion 4b is the second bonding material 3b and the auxiliary second bonding material. The case where 3bb is similar to each other is also included. At this time, the metal components of the second joining material 3b and the auxiliary second joining material 3bb may be slightly different from each other. That is, as a structure, the auxiliary second joining material 3bb may be the same as the second joining material 3b. However, the numerical values such as the volume ratio of the voids 4a may be slightly different between the second joining material 3b and the auxiliary second joining material 3bb.

As described above, the semiconductor package of the embodiment of the present invention has the following configuration. That is, the semiconductor package 10 of the present embodiment has a substrate 5 having a first surface 5a and a second surface 5b opposite to the first surface 5a, a line conductor 2 located on the first surface 5a side of the substrate 5, and a substrate. A metal terminal 1 that penetrates from the second surface 5b to the first surface 5a of 5 and has an end portion 1a on the first surface 5a side, and a metal particle, and includes the end portion 1a of the metal terminal 1 and a line conductor. It has a joint portion 3 interposed between the two. Further, the semiconductor package 10 of the present embodiment has a bonding structure C having any of the above configurations between the end portion 1a of the metal terminal 1 and the line conductor 2.

According to the semiconductor package 10 of the above-described embodiment, since the junction structure C having any of the above configurations is provided, the semiconductor package 10 having high mechanical and electrical connection reliability between the metal terminal 1 and the line conductor 2 is provided. be able to.

The first surface 5a side of the substrate 5 is the side sealed by the metal case described above. The end 1a of the semiconductor element and the metal terminal 1 is sealed in the space formed between the substrate 5 and the metal case. Further, in the examples shown in FIGS. 4 and 5, the sealing material (unsigned) is located in the through hole 5c of the substrate 5. The sealing material has a function of closing the gap between the metal terminal 1 and the through hole 5c. The sealing material 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 soda glass, and those obtained by adding a ceramic filler for adjusting the coefficient of thermal expansion and the relative permittivity to these glasses. This insulating material can be appropriately selected in consideration of impedance matching (relative permittivity) in the metal terminal 1 and reliability of sealing.

The submount 7 is provided on the first surface 5a of the substrate 5 and has a substrate mounting surface parallel to the first surface 5a. In the semiconductor package 10, the submount 7 has a function of conducting heat generated by electronic components mounted on the insulating plate 6 to the substrate 5. That is, the submount 7 has a function as a heat radiating material that dissipates heat to the outside of the semiconductor package 10.

The submount 7 may be formed integrally with the substrate 5 and may include a cooling member (for example, a Pelche element). When the submount 7 is integrally formed with the substrate 5, the submount 7 is made of the same metal material as the substrate 5. As a result, the heat dissipation property of the semiconductor package 10 is effectively ensured.

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

For example, as shown in FIG. 7, the joint portion 3 is not joined to the pin terminal 1 in a wide range of the end portion 1a facing the line conductor 2 from the tip end (right end in FIG. 7) of the pin terminal 1. It may be. In this case, the joint portion 3 smoothly forms the fillet F from the center of the tip portion of the pin terminal 1 to the line conductor 2 facing the end portion 1a. Note that FIG. 7 is a cross-sectional view showing a joining structure of another embodiment of the present invention. In FIG. 7, the same parts as those in FIGS. 1 to 5 are designated by the same reference numerals.

In the example shown in FIG. 7, the presence of the fillet F can also improve the joint strength of the joint portion 3 with respect to the line conductor 2. Therefore, the joint structure C and the semiconductor package 10 that are effective in improving the joint strength and connection reliability between the line conductor 2 and the metal terminal 1 via the joint portion 3 can be obtained.

1 ・ ・ Metal terminal 1a ・ ・ End 2 ・ ・ Line conductor 3 ・ ・ Joint 3A ・ ・ Auxiliary joint 3a ・ ・ 1st joint 3b ・ ・ 2nd joint 3bb ・ ・ Auxiliary 2nd joint 3c ・・ Third joint material 3cc ・ ・ Auxiliary third joint material 4a ・ ・ Void 4b ・ ・ Columnar part 5 ・ ・ Substrate 5a ・ ・ First surface 5b ・ ・ Second surface 5c ・ ・ Through hole 6 ・ ・ Insulation plate 7 ・・ Sub mount 8 ・ ・ Ground terminal 9 ・ ・ Diffusion layer
10 ... Semiconductor package C ... Bonding structure F ... Fillet

Claims (8)

With metal terminals with ends,
With the line conductor where the end of the metal terminal is located,
It is provided with a joint portion for joining the end portion of the metal terminal and the line conductor.
The joint contains metal particles and is located between the metal particles and the metal particles with a first bonding material including a portion located between the end of the metal terminal and the line conductor. It contains a gap and has a second bonding material interposed between the first bonding material and the line conductor .
The first bonding material further contains voids located between the metal particles.
A bonding structure in which the proportion of the voids in the second bonding material is larger than the proportion of the voids in the first bonding material. With metal terminals with ends,
With the line conductor where the end of the metal terminal is located,
It is provided with a joint portion for joining the end portion of the metal terminal and the line conductor.
The joint contains metal particles and is located between the metal particles and the metal particles with a first bonding material including a portion located between the end of the metal terminal and the line conductor. It contains a gap and has a second bonding material interposed between the first bonding material and the line conductor.
The joint portion is mainly composed of the same metal material as the metal particles and is composed of a thin layer located along the surface of the line conductor, and is interposed between the second joint material and the line conductor. junction structure that further have a third bonding material containing portion are. The bonding structure according to claim 2, wherein a diffusion layer containing both the components of the third bonding material and the line conductor is interposed at the interface portion between the third bonding material and the line conductor. The invention according to any one of claims 1 to 3 , wherein at least one of the voids in the first bonding material and the voids in the second bonding material includes a columnar space located between the metal particles. Joint structure. The joining structure according to any one of claims 1 to 4, wherein the second joining member is located in a region of the line conductor facing the metal terminal via the joining portion. The bonding structure according to any one of claims 1 to 5, wherein the metal particles are silver particles. It is interposed between the first joining material and the metal terminal, and the second joining material and the third joining material.
The joining structure according to claim 2 or 3 , further comprising an auxiliary joining portion having the same composition as any of the joining materials. 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 and
It penetrates from the second surface to the first surface of the substrate, and is provided with a metal terminal having an end portion on the first surface side.
It contains metal particles and includes a joint that is interposed between the end of the metal terminal and the line conductor.
A semiconductor package having the bonding structure according to any one of claims 1 to 7, between the end of the metal terminal and the line conductor.

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