Patent Application
20240258134
The present disclosure relates to a semiconductor manufacturing apparatus and a method for manufacturing a semiconductor manufacturing apparatus.
JP 2020-150020 A discloses a technique for suppressing the temperature of each terminal, which protrudes from a sealing resin body sealing a semiconductor device, when a current is flowed therethrough by changing the width of the terminal.
However, the foregoing method of changing the width of each terminal has a limitation in reducing the temperature of the terminal due to restrictions on the terminal in the thickness direction.
To solve the foregoing problem, it is a primary object of the present disclosure to provide a semiconductor manufacturing apparatus that can suppress a temperature rise of the apparatus by devising the shapes of terminals.
It is a secondary object of the present disclosure to provide a method for manufacturing a semiconductor manufacturing apparatus that can suppress a temperature rise of the apparatus by devising the shapes of terminals.
The features and advantages of the present disclosure may be summarized as follows.
According to one aspect of the present disclosure, a semiconductor manufacturing apparatus comprises a semiconductor module including a semiconductor device, a sealing material adapted to seal the semiconductor module, and a second terminal to be arranged outside the sealing material. The semiconductor module includes a first terminal that is electrically connected to the semiconductor device and extends to outside of the sealing material, and the first terminal is joined to the second terminal outside the sealing material. A thickness of the second terminal in a direction perpendicular to a joined face of the first terminal and the second terminal is defined as a thickness of the second terminal, and a thickness of the first terminal at a portion extending from the sealing material in the direction perpendicular to the joined face is defined as a thickness of the first terminal. The thickness of the second terminal is greater than the thickness of the first terminal.
According to another aspect of the present disclosure, a method for manufacturing a semiconductor manufacturing apparatus, comprises a first step of sealing a semiconductor module including a semiconductor device using a sealing material; and a second step of joining a first terminal that is electrically connected to the semiconductor device and extends to outside of the sealing material to a second terminal arranged outside the sealing material, thereby electrically connecting the first terminal and the second terminal. A thickness of the second terminal in a direction perpendicular to a joined face of the first terminal and the second terminal is defined as a thickness of the second terminal, and a thickness of the first terminal at a portion extending from the sealing material in the direction perpendicular to the joined face is defined as a thickness of the first terminal. The thickness of the second terminal is greater than the thickness of the first terminal.
Other and further objects, features and advantages of the invention will appear more fully from the following description.
The sealing material 140 is adapted to seal the semiconductor module 110. The material of the sealing material 140 is desirably the one that can improve the reliability of the semiconductor module 110. For example, a thermosetting resin material is used. As a sealing method, transfer molding is used, for example.
The semiconductor module 110 is sealed with the sealing material 140. The semiconductor module 110 includes a plurality of first terminals 130. The first terminals 130 are terminals for electrically connecting the semiconductor module 110 to the second terminals 120. The first terminals 130 are extended to the outside of the sealing material 140 so as to be joined to the respective second terminals 120 outside the sealing material 140. Joining the corresponding terminals outside the sealing material 140 can suppress the self-heating of the terminals when a current is flowed therethrough, and thus can suppress a temperature rise of the semiconductor manufacturing apparatus 100. For the joining, laser welding is used.
The first terminals 130 are broadly classified into main terminals and signal terminals. Each main terminal is electrically connected to an emitter electrode or a collector electrode of each semiconductor device 111 included in the semiconductor module 110. Meanwhile, each signal terminal is electrically connected to a signal input portion of each semiconductor device 111. The signal input portion is a gate electrode, for example. For each of the main terminals and the signal terminals, a copper material with a thickness of 0.64 mm may be used, for example.
The second terminals 120 are arranged outside the sealing material 140, and are joined to the respective first terminals 130 of the semiconductor module 110. For the second terminals 120, a material with a high heat capacity is preferably used. For example, copper is used.
In
The semiconductor device 111 is not limited to the one formed of silicon, and may be the one formed of a wide-band-gap semiconductor with a band gap wider than that of silicon. Examples of the wide-band-gap semiconductor include silicon carbide, a gallium nitride-based material, and diamond. A semiconductor device formed of such a wide-band-gap semiconductor has a high withstand voltage and high tolerable current density, and thus can be reduced in size. Using such a semiconductor device with a reduced size can also achieve a reduction in the size and an increase in the integration degree of the semiconductor manufacturing apparatus 100 incorporating the semiconductor device. In addition, since the semiconductor device has high heat resistance, radiating fins of a heat sink can be reduced in size, and a water-cooled portion can be formed as an air-cooled portion. Thus, the semiconductor manufacturing apparatus 100 can be further reduced in size. Further, since the semiconductor device has a low power loss and thus has high efficiency, the semiconductor manufacturing apparatus 100 can also be increased in efficiency. Although all of the semiconductor devices 111 are desirably formed of a wide-band-gap semiconductor, it is acceptable as long as one of the semiconductor devices 111 is formed of a wide-band-gap semiconductor, and the advantageous effects described in the present embodiment can be obtained even with such a configuration. This point is also common to all of the following embodiments.
A jointing material 112 is arranged between each semiconductor device 111 and a metal pattern 113, between each semiconductor device 111 and each first terminal 130, and between each first terminal 130 and the metal pattern 113. The jointing material 112 is preferably a member with high electrical conductivity and high thermal conductivity. For example, using lead-free solder, which has the role of a buffer material for reducing stress in addition to the foregoing characteristics, can improve the reliability of the semiconductor manufacturing apparatus 100. Besides, sintered silver may be used.
To design the heat radiation of the metal pattern 113, using a copper material with high thermal conductivity can improve the heat radiation property. For example, using copper with a thickness of 3 mm can diffuse heat in a direction perpendicular to the thickness direction, and thus can efficiently radiate heat. However, the thickness is not limited thereto, and copper with a thickness of 0.8 mm or 0.25 mm may also be used.
An insulating layer 114 is arranged between the metal pattern 113 and a metal member 115. Using the insulating layer 114 made of a resin that is resistant to deformation can suppress the generation of cracks even when small deformation of the member has occurred due to the heat cycle, for example. In addition, using a material with high thermal conductivity can improve the property of radiating heat from the metal pattern 113 to the metal member 115 via the insulating layer 114, and thus can suppress a temperature rise of the semiconductor manufacturing apparatus 100. For example, the insulating layer 114 is a resin containing highly thermal conductive fillers and having a thermal conductivity of greater than or equal to 10 W/m□K. The material of the insulating layer 114 is not limited to a resin, and any one of AlN, Al2O3, and Si3N4 may be used.
To design the heat radiation of the metal member 115, using a copper material with high thermal conductivity can improve the heat radiation property. For example, a copper foil with a thickness of 0.105 mm is used.
It should be noted that the thickness a of each second terminal 120 is the thickness of the second terminal 120 in a direction perpendicular to the joined face where the second terminal 120 is joined to each first terminal 130. In addition, the thickness b of each first terminal 130 is the thickness of the first terminal 130 at a portion extending from the sealing material 140 in the direction perpendicular to the joined face.
Herein, it is also possible to set the width of each second terminal 120 to be greater than the width of each first terminal 130 to make the area of the cross-section of each second terminal 120 to be larger than the area of the cross-section of each first terminal 130. However, since it is often the case that each first terminal 130 is placed on each second terminal 120 during the manufacturing steps, the width of each second terminal 120 is preferably smaller than the width of each first terminal 130 from the perspective of workability.
Thus, in the present disclosure, the thickness of each terminal is adjusted so that the area of the cross-section of the terminal is adjusted. This can improve the workability in the manufacturing steps and the heat radiation property of the semiconductor manufacturing apparatus 100 at the same time.
Herein, the thermal resistivity of each first terminal 130 becomes higher in proportion to the length c of the first terminal 130, and is inversely proportional to the area g of its cross-section (hereinafter referred to as a cross-sectional area g). That is, as the length c is greater and the cross-sectional area g is smaller, the amount of heat generated by the first terminal 130 when a current is flowed therethrough would increase. Since the cross-sectional area g of the first terminal 130 is represented by the product of the width d and the thickness b (d×b), it is preferable to increase the width d to increase the cross-sectional area g. Setting the width d of the first terminal 130 to be greater than the length c can cancel the thermal resistivity generated in proportion to the length c.
As described in the first embodiment, the width of each second terminal 120 is preferably set smaller than the width d of each first terminal 130 from the perspective of workability. That is, the area (c×d) of the upper surface of each first terminal 130 is preferably set larger than the area f of the joined face 150 of each first terminal 130 and each second terminal 120. That is, c×d>f is preferably satisfied.
Thus, for each first terminal 130, c×d>f and d>c are more preferably satisfied.
The drawings of the present embodiment are common to those of the second embodiment. In a semiconductor manufacturing apparatus 300 of the present embodiment, the cross-sectional area g=d×b of the extending portion of each first terminal 130 is set smaller than the area f of the joined face 150 of each first terminal 130 and each second terminal 120 (f>g).
As described in the first embodiment, each first terminal 130 and each second terminal 120 are joined together by laser welding. Setting the cross-sectional area g=d×b of each first terminal 130 to be smaller than the area f of the joined face 150 can suppress the transmission of heat, which is applied to the to-be-joined portion during welding, to each semiconductor device 111 within the sealing material 140 via the first terminal 130.
Each second terminal 120 is partially cut off on the side of the joined face 150, and thus has a U-shape. This can reduce the heat capacity of each second terminal 120, and thus can reduce the heat flowing into the semiconductor module 110.
The shape of each second terminal 120 is not limited to a U-shape, and it is acceptable as long as each second terminal 120 is partially cut off on the side of the joined face where the second terminal 120 is joined to each first terminal 130.
In the second step, laser joining is performed by emitting the beam 11 of the laser 10 from the side of the first terminal 130. Performing laser welding from the side of the first terminal 130, which is thinner than the second terminal 120, can reduce the output of the beam 11. This can reduce the heat flowing into the semiconductor module 110. In the semiconductor manufacturing apparatus 700, the thickness a of each second terminal 120 is greater than the thickness b of each first terminal 130 as in the first embodiment.
However, in the second step of the present embodiment, laser welding is performed by emitting the beam 11 from the side of the second terminal 120.
Herein, in the semiconductor manufacturing apparatus 800, the thickness a of each second terminal 120 needs to be greater than the thickness b of each first terminal 130 as described above. In the present embodiment, laser welding is performed from the side of the second terminal 120 that is thicker than the first terminal 130. Thus, even if the dent 820 is generated, the degree of the generated dent 820 can be suppressed as long as the laser 10 with the ordinary output is used. That is, it is possible to guarantee that the thickness h of the dent 820 is greater than or equal to the thickness b of the first terminal 130. Therefore, the semiconductor manufacturing apparatus 800 can be manufactured that can efficiently radiate heat, which has been generated by the semiconductor module 110, toward the second terminal 120.
As described above, the present disclosure can provide a semiconductor manufacturing apparatus and a method for manufacturing a semiconductor manufacturing apparatus that can suppress a temperature rise of the apparatus by devising the shapes of terminals.
The technical features described in the present disclosure may be combined as appropriate. Alternatively, some of the technical features of the present disclosure may be extracted to provide a new semiconductor manufacturing apparatus and a method for manufacturing the same that are different from those of the present disclosure.
Obviously many modifications and variations of the present disclosure are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.
The entire disclosure of Japanese Patent Application No. 2023-13151, filed on Jan. 31, 2023 including specification, claims, drawings and summary, on which the convention priority of the present application is based, is incorporated herein by reference in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-013151 | Jan 2023 | JP | national |
