JP2007027227A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device having such a structure that can suppress the scattering of solder during manufacturing. <P>SOLUTION: The semiconductor device 10 has such a structure that a supporting body 18 is bonded to the rear face 20 of a substrate 16 formed with storage holes 22 for storing semiconductor components 12 by means of solder 30, and that the semiconductor components 12 are mounted on part of the supporting body 18 which can be seen through the storage holes 22. The substrate 16 has through-holes 26 for connecting the rear face 20 and the principal plane 24 opposite to the rear face at least in the periphery of the storage holes 22. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a semiconductor device and a method for manufacturing the semiconductor device, and more particularly to a method in which components of a semiconductor device are joined by solder.

A semiconductor element that generates heat is mounted on a substrate with low thermal conductivity in a high-frequency power amplifier module with a matching circuit used for communications such as commercial radio and LAN, etc., which has a relatively large power exceeding 1 W. Instead, there are those mounted on a support having high thermal conductivity, for example, a heat sink. For example, in a semiconductor device having a structure in which a heat sink and a back surface of a substrate are bonded by solder, a housing hole (cavity) that can accommodate a semiconductor element (or a semiconductor component having a semiconductor element) is formed in the substrate, and the cavity is formed. Some semiconductor elements or semiconductor components are mounted directly on the heat sink plate that can be seen through, or mounted via a pedestal. The semiconductor element or the semiconductor component is electrically connected to a terminal provided on the cavity edge of the main surface of the substrate. Such a semiconductor device is called a cavity down type semiconductor device. As an example of the cavity down type semiconductor device, there is one of Patent Document 1.
JP-A-11-97567

  However, in a semiconductor device in which a cavity is formed in a substrate that is bonded to a heat sink by solder, the volume of the solder contained in the solder is melted and liquefied or vaporized during the melting of the solder and ejected from the cavity. As a result, flux and molten solder powder may be scattered from the cavity. As a result, molten solder powder or flux may adhere to the main surface of the substrate.

  Therefore, the present invention provides a semiconductor having a structure that suppresses the adhesion of the main surface of the substrate to the solder (flux or molten solder powder) that scatters from the cavity in the heating process when the back surface of the substrate and the support are joined by solder. An object is to provide a device and a method for manufacturing a semiconductor device.

In order to achieve the above object, a semiconductor device according to the present invention includes:
A semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
The substrate has a through hole that communicates at least the back surface and the main surface opposite to the back surface at the periphery of the accommodation hole.

  According to the present invention, since a plurality of through holes that connect the main surface and the back surface are formed at the peripheral portion of the accommodation hole of the substrate, during the melting of the solder, the liquefied or vaporized solder between the substrate and the support body The movement of the flux is dispersed in the accommodation hole and the plurality of through holes. As a result, the amount of flux ejected from the accommodation hole is reduced as compared with the case where a plurality of through holes are not formed in the substrate. As a result, the adhesion of the solder ejected from the accommodation hole to the main surface of the substrate is suppressed.

  First, in this specification, “solder” refers to a mixture of solder powder and flux. The solder powder is, for example, a powder of tin, lead or the like, which joins the members to be joined by melting and solidifying between the members to be joined. On the other hand, the flux refers to, for example, a resin, which improves the wettability of the bonded member and the solder powder melted by removing the surface oxide of the bonded member.

Embodiment 1 FIG.
FIG. 1A shows a top view of a semiconductor device according to an embodiment of the present invention, and FIG. 1B shows a cross-sectional view of the semiconductor device viewed from the A direction in FIG. A semiconductor device denoted by reference numeral 10 in FIG. 1 is a so-called cavity down type semiconductor device, and is generally electrically connected to the semiconductor chip 12, a pedestal 14 on which the semiconductor chip 12 is mounted, and the semiconductor chip 12. And a heat sink 18 to which the substrate 16 is bonded.

  The semiconductor chip 12 is mounted via a pedestal 14 on a portion of the heat dissipation plate 18 that can be seen through a hole (cavity) 22 formed in the substrate 16 in which the rear surface 20 is bonded to the heat dissipation plate 18. The pedestal 14 is made of a material that takes into account the difference in coefficient of linear expansion between the semiconductor chip 12 and the heat sink 18 while being excellent in thermal conductivity. Thereby, the heat generated from the semiconductor chip 12 during driving of the semiconductor device 10 is efficiently transmitted to the heat radiating plate 18.

  The cavity 22 is formed on the substrate 16 in such a size as to sufficiently accommodate the pedestal 14 on which the semiconductor chip 12 is mounted, that is, such that a gap is formed between the inner peripheral surface of the cavity 22 and the pedestal 14. Has been.

  In the substrate 16, a plurality of through holes (holes connecting the main surface 24 and the back surface 20 of the substrate 16) 26 are formed at least at the peripheral edge of the cavity 22. The plurality of through holes 26 are not involved in driving the semiconductor device 10 and function in the manufacture of the semiconductor device 10. The manufacture of the semiconductor device 10 will be described later.

  In addition, the peripheral portion of the cavity 22 of the main surface 24 of the substrate 16 has a connection portion (not shown) that is electrically connected to the semiconductor chip 12 by a bonding wire 28.

  Next, a method for manufacturing the semiconductor device 10, specifically, a method for bonding the substrate 16 and the heat sink 18 will be described.

  The substrate 16 and the heat radiating plate 18 are joined by solder 30. First, cream-like solder (so-called solder paste, which is composed of solder powder and paste-like flux) 30 is applied to either the back surface 20 of the substrate 16 or the bonding surface of the heat sink 18 to the substrate 16. A uniform thickness is applied by a squeegee. Next, the substrate 16 and the heat radiating plate 18 are overlapped via the solder 30. Subsequently, in order to melt the solder 30, for example, the substrate 16 and the heat radiating plate 18 that are superposed via the solder 30 are placed in a furnace and heated.

  In the melting process of the solder 30, the paste-like flux contained in the solder 30 is liquefied or vaporized, and moves (spouts) from between the substrate 16 and the radiator plate 18. At this time, the liquefied or vaporized flux moves to the outside through a plurality of through holes 26 and cavities 22 provided in the substrate 16. The amount of the liquefied or vaporized flux that moves outside through the cavity 22 is smaller than that in the case where the plurality of through holes 26 are not formed in the substrate 16, thereby causing the flux to be ejected from the cavity 22. The amount of molten solder powder and flux scattered from the cavity is also reduced. As a result, the amount of solder (molten solder powder or flux) adhering to the main surface of the substrate 16 is reduced.

  After the solder 30 is sufficiently melted, in order to solidify the solder 30, the substrate 16 and the heat radiating plate 18 in a state of being overlapped with each other through the solder 30 are removed. And the board | substrate 16 and the heat sink 18 are joined. In addition to joining the substrate 16 and the heat sink 18 with the solder 30, the base 14 on which the semiconductor chip 12 is mounted and the heat sink 18 may be joined in the same process.

Embodiment 2. FIG.
In the above-described embodiment, the amount of solder scattered from the cavity is reduced by forming a plurality of through holes in the substrate. In the present embodiment, the amount of solder scattered from the cavity is suppressed by forming a through hole in the heat sink.

  FIG. 2A shows a top view of the semiconductor device according to this embodiment, and FIG. 2B shows a cross-sectional view of the semiconductor device viewed from the B direction in FIG.

  In the semiconductor device denoted by reference numeral 110 in FIG. 2, a different point from the semiconductor device 10 of the first embodiment is a heat radiating plate 118. Therefore, the heat sink 118 will be described.

  The heat radiating plate 118 is a surface (back surface) facing the bonding surface 132 from a surface (bonding surface) 132 bonded to the substrate 116 via the solder 130 at least in a portion facing the peripheral portion of the cavity 122 of the back surface 120 of the substrate 116. ) 134 having a plurality of through holes 136 communicating with each other. The through holes 136 function in the same manner as the plurality of through holes 26 formed in the substrate 16 of the semiconductor device 10 of the first embodiment, and the solder that scatters from the cavity 122 when the substrate 116 and the heat sink 118 are joined by the solder 130. Reduce the amount.

  The layout of the plurality of through holes 26 formed in the substrate 16 in the first embodiment is limited by, for example, the terminals of the bonding wires 28, but the layout of the through holes 136 formed in the heat sink 118 of the present embodiment. Is not greatly limited.

Embodiment 3 FIG.
Unlike the second embodiment, the present embodiment is characterized in that a groove is formed in the heat sink instead of the through hole.

  FIG. 3A shows a top view of the semiconductor device according to this embodiment, and FIG. 3B shows a cross-sectional view of the semiconductor device viewed from the C direction in FIG.

  In the semiconductor device denoted by reference numeral 210 in FIG. 3, a different point from the semiconductor device 110 of the second embodiment is a heat sink 218. Therefore, the heat sink 218 will be described.

  The heat radiating plate 218 is connected to a surface (joint surface) 232 that is joined to the substrate 216 via the solder 230 and communicates with the side surface 238 of the semiconductor device 210 from a portion facing the peripheral edge of the cavity 222 on the back surface 220 of the substrate 216. A plurality of grooves 240 are formed. The groove 240 plays a role of guiding the flux of the solder 230 that is about to move from between the substrate 216 and the heat sink 218 to the side surface 238 and suppressing the amount of flux ejected from the cavity 222. As a result, the amount of solder scattered from the cavity 222 when the substrate 216 and the heat sink 218 are joined by the solder 230 is suppressed.

  Unlike the second embodiment, the semiconductor device of the present embodiment has no through-hole opening formed on the back surface of the heat sink, so that other semiconductor device components can be attached to the back surface of the heat sink.

Embodiment 4 FIG.
The semiconductor device of the present embodiment has a through hole that communicates the side surface of the heat sink from the joint surface of the heat sink, whereas the second embodiment has a through hole that communicates the back surface from the joint surface of the heat sink. There is a feature.

  FIG. 4A shows a top view of the semiconductor device according to this embodiment, and FIG. 4B shows a cross-sectional view of the semiconductor device viewed from the D direction in FIG. 4A.

In the semiconductor device denoted by reference numeral 310 in FIG. 4, a different point from the semiconductor device 110 of the second embodiment is a heat sink 318. Therefore, the heat sink 318 will be described.

  The heat radiating plate 318 has a plurality of through holes 342 that communicate with the side surface 338 of the semiconductor device 310 from at least a portion of the back surface 320 of the substrate 316 facing the peripheral edge of the cavity 322. The through hole 342 functions in the same manner as the plurality of through holes 126 of the semiconductor device 110 of the second embodiment, and suppresses the amount of solder scattered from the cavity 322 when the substrate 316 and the heat sink 318 are joined by the solder 330.

  This embodiment is effective when the size of the semiconductor device is small. The flow path for moving the flux from the joining surface of the heat sink to the side is formed in the same manner as the groove of the third embodiment, but the heat sink of the present embodiment is configured with a through hole. By doing so, a sufficiently large bonding surface with respect to the substrate is secured. When the size of the semiconductor device is reduced in the third embodiment, the area occupied by the groove with respect to the bonding surface increases, and the surface substantially bonded to the substrate decreases. When the substantial joint surface between the heat sink and the substrate is reduced, electrical or thermal connection may not be sufficiently performed, and the semiconductor device may not perform a sufficient function.

  Up to this point, during the melting of solder in the manufacture of semiconductor devices, the amount of flux ejected from the cavity of the substrate is suppressed, thereby suppressing the amount of solder scattered from the cavity and, as a result, adhering to the main surface of the substrate. A semiconductor device having a structure capable of suppressing the amount of solder to be processed has been described. From here, a method for manufacturing a semiconductor device capable of suppressing the amount of solder adhering to the main surface of the substrate will be described.

  The semiconductor device manufacturing method described below is a so-called cavity down type semiconductor device manufacturing method including the semiconductor devices according to the first to fourth embodiments. Therefore, the description of the components of the semiconductor device is omitted.

Embodiment 5. FIG.
FIG. 5A shows a top view of the semiconductor device being manufactured in the manufacturing method of the present embodiment, and FIG. 5B shows a cross-sectional view of the semiconductor device viewed from the E direction in FIG. 5A.

  In the manufacturing method of the semiconductor device of this embodiment, the solder 430 scattered from the cavity 422 of the substrate 416 is adhered to the main surface 424 of the substrate 416 during the bonding of the substrate 416 and the heat sink 418 (during melting of the solder 430). In order to prevent this, the adhesion preventing member 444 is placed on the main surface 424 of the substrate 416. The prevention member 444 is a tape, a seal, or a film that can be attached to and detached from the substrate 416. At least a part that is inconvenient when the solder 430 is attached, for example, a bonding wire around the cavity 422 as shown in FIG. (See FIGS. 1 to 4). Of course, the prevention member 444 has heat resistance that can withstand a high heat environment for melting the solder 430. The prevention member 444 prevents the solder 430 scattered from the cavity 422 from adhering to the main surface 424 of the substrate 416.

Embodiment 6 FIG.
FIG. 6A shows a top view of the semiconductor device being manufactured in the manufacturing method of the present embodiment, and FIG. 6B shows a cross-sectional view of the semiconductor device viewed from the F direction in FIG. 6A.

  In the manufacturing method of the semiconductor device of this embodiment, the solder 530 scattered from the cavity 522 of the substrate 516 is adhered to the main surface 524 of the substrate 516 during the joining of the substrate 516 and the heat sink 518 (during melting of the solder 530). In other words, the cavity 522 is covered with the member 546 in order to capture the solder 530 scattered from the cavity 522 so as not to exit the cavity 522. The member 546 is made of, for example, metal wool, carbon fiber, heat-resistant paper, heat-resistant fiber, etc., which are excellent in heat resistance through which air can pass. The reason why air can pass through the member 546 is to release the flux that is vaporized and jetted into the cavity 522 to the outside. The solder 530 scattered from the cavity 522 is captured by the capture member 546, and as a result, the solder 530 scattered from the cavity 522 is prevented from adhering to the main surface 524 of the substrate 516.

Embodiment 7 FIG.
FIG. 7A shows a top view of the semiconductor device being manufactured in the manufacturing method of the present embodiment, and FIG. 7B shows a cross-sectional view of the semiconductor device viewed from the G direction in FIG. 7A.

  In the manufacturing method of the semiconductor device of the present embodiment, the solder 630 scattered from the cavity 622 of the substrate 616 is adhered to the main surface 624 of the substrate 616 during the bonding of the substrate 616 and the heat sink 618 (melting of the solder 630). In other words, in order to absorb the liquid flux of the solder 630 ejected from the space between the substrate 616 and the heat sink 618 that causes the solder 630 to scatter from the cavity 622, the inner peripheral surface of the cavity 622 is absorbed. A plurality of absorbing members 648 that absorb the flux are disposed along the line. The absorbing member 648 corresponds to, for example, a member that can absorb a liquid using a capillary tube or a capillary phenomenon (for example, a sponge member). The absorbing member 648 absorbs the liquid flux of the solder 630 ejected from between the plate 616 and the heat radiating plate 618 to the cavity 622, thereby reducing the amount of the solder 630 scattered from the cavity 622, and as a result, from the cavity 622. Adhesion of the scattered solder 630 to the main surface 624 of the substrate 616 is suppressed.

Embodiment 8 FIG.
FIG. 8 shows a semiconductor device being manufactured in the manufacturing method of the present embodiment.

  In the manufacturing method of the semiconductor device of this embodiment, the substrate 716 of the solder scattered from the cavity 722 of the substrate 716 during the bonding of the substrate 716 and the heat dissipation plate 718 (during melting of the solder for bonding the substrate 716 and the heat dissipation plate 718). In order to prevent the main surface 724 from adhering to the main surface 724, a blower 752 that generates an airflow 750 that blows away the solder scattered from the cavity 722 away from the semiconductor device 710 is disposed. The airflow 750 flows substantially parallel to the main surface 724 of the substrate 716. The solder scattered from the cavity 722 is blown away from the semiconductor device 710 by the air current 750, and as a result, the adhesion of the solder scattered from the cavity 722 to the main surface 724 of the substrate 716 is suppressed.

  As an improved example of the eighth embodiment, as shown in FIG. 9, an ascending air current 856 is generated on the cavity 822 by the suction device 854, and the solder 830 scattered from the cavity 822 by the ascending air current 856 is separated from the semiconductor device 830. You may make it blow away. Strictly speaking, the solder 830 scattered from the cavity 822 is sucked by the suction device 854.

Embodiment 9 FIG.
FIG. 10 shows a semiconductor device being manufactured in the manufacturing method of the present embodiment.

  In the method for manufacturing a semiconductor device of this embodiment, the solder 930 scattered from the cavity 922 of the substrate 916 during the bonding of the substrate 916 and the heat sink 918 (during melting of the solder 930) to the main surface 924 of the substrate 916. In order to prevent this, the substrate 916 and the heat radiating plate 918 are joined in a chamber 958 having an internal pressure higher than the vapor pressure of the solder 930 flux. The scattering of the solder 930 from the cavity 922 is greatly influenced by the volume expansion due to the rapid evaporation of the paste-like flux of the solder 930 between the substrate 916 and the heat sink 918. In the present embodiment, the internal pressure of the chamber 958 is made higher than the vapor pressure at the temperature at which the flux of the solder 930 vaporizes, thereby suppressing rapid volume expansion of the flux, and thereby the main surface of the substrate 916 from the cavity 922. The amount of solder 930 that scatters to 924 is reduced.

Embodiment 10 FIG.
FIG. 11 shows a semiconductor device being manufactured in the manufacturing method of the present embodiment.

  In the manufacturing method of the semiconductor device of this embodiment, the solder 1030 scattered from the cavity 1022 of the substrate 1016 is adhered to the main surface 1024 of the substrate 1016 during the bonding of the substrate 1016 and the heat sink 1018 (during melting of the solder 1030). In order to prevent this, the substrate 1016 is disposed with the back surface 1020 facing upward, and the heat radiating plate 1018 is joined to the substrate 1016 with solder 1030 from above. The solder 1030 scattered from the cavity 1022 falls due to gravity. Thereby, adhesion of the solder 1030 scattered from the cavity 1022 to the main surface 1024 of the substrate 1016 is suppressed.

  While the present invention has been described with reference to some embodiments, the present invention is not limited to these embodiments. For example, what is joined to the substrate does not have to be a heat sink, and may be anything that supports the substrate and the semiconductor chip (pedestal). Moreover, although a semiconductor chip is mounted on a heat sink via a pedestal, it may be mounted directly on the heat sink. Further, it may be a semiconductor device having all the structures of the second to fourth embodiments.

  Finally, the above-described embodiments can be implemented in combination. For example, the manufacturing method of the fifth to tenth embodiments can be carried out for the manufacture of the semiconductor device having the structure of the first to fourth embodiments. When used together, the adhesion of the solder ejected from the cavity to the main surface of the substrate is further suppressed.

1 is a diagram illustrating a semiconductor device according to a first embodiment of the present invention. It is a figure which shows the semiconductor device which concerns on Embodiment 2 of this invention. It is a figure which shows the semiconductor device which concerns on Embodiment 3 of this invention. It is a figure which shows the semiconductor device which concerns on Embodiment 4 of this invention. It is a figure which shows the manufacturing method of the semiconductor device which concerns on Embodiment 5 of this invention. It is a figure which shows the manufacturing method of the semiconductor device which concerns on Embodiment 6 of this invention. It is a figure which shows the manufacturing method of the semiconductor device which concerns on Embodiment 7 of this invention. It is a figure which shows an example of the manufacturing method of the semiconductor device which concerns on Embodiment 8 of this invention. It is a figure which shows another example of the manufacturing method of the semiconductor device which concerns on Embodiment 8 of this invention. It is a figure which shows the manufacturing method of the semiconductor device which concerns on Embodiment 9 of this invention. It is a figure which shows the manufacturing method of the semiconductor device which concerns on Embodiment 10 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Semiconductor device, 12 Semiconductor components (semiconductor chip), 16 Board | substrate, 18 Support body (heat sink), 20 Back surface, 22 Housing hole (cavity), 24 Main surface, 26 Through-hole, 30 Solder

Claims (8)

A semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
The substrate has a through hole that connects at least a back surface and a main surface facing the back surface at a periphery of the accommodation hole. A semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
The support body has at least one of a through hole or a groove that communicates at least a portion facing the peripheral portion of the accommodation hole on the back surface of the substrate and a portion not joined to the substrate. A method of manufacturing a semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
A semiconductor device characterized in that a member for preventing adhesion of solder ejected from a receiving hole to a main surface of a substrate when the back surface of the substrate and a support are bonded to each other is placed on the main surface of the substrate. Manufacturing method. A method of manufacturing a semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
A method for manufacturing a semiconductor device, wherein when a back surface of a substrate and a support are joined with solder, the housing hole is covered with a member that allows air to pass therethrough and captures the solder ejected from the housing hole. A method of manufacturing a semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
Manufacturing of a semiconductor device characterized in that when a back surface of a substrate and a support are joined with solder, an absorbing member for absorbing solder flux eluted from between the substrate and the support into the accommodation hole is disposed in the accommodation hole. Method. A method of manufacturing a semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
A method of manufacturing a semiconductor device, characterized in that when the back surface of the substrate and the support are joined with solder, the solder ejected from the accommodation hole is blown away or sucked away from the semiconductor device using a blowing means or a suction means. A method of manufacturing a semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
A method for manufacturing a semiconductor device, comprising: joining a back surface of a substrate and a support by solder under a pressure higher than a vapor pressure of a solder flux. A method of manufacturing a semiconductor device in which a back surface of a substrate on which a housing hole for a semiconductor component is formed and a support are joined by solder, and the semiconductor component is mounted on a portion of the support that can be seen through the housing hole,
A method of manufacturing a semiconductor device, wherein when a back surface of a substrate and a support are joined by solder, the substrate is arranged with the back surface facing upward, and the support is joined to the substrate from above by solder.

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