JP2015070053A - Junction assembly apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a junction assembly apparatus capable of obtaining a joined body in which bubbles are less in a solder joint layer, by joining a laminate of at least one joined member and at least one solder material by short time soldering.SOLUTION: A junction assembly apparatus includes in a vacuum oven 11 a metal wire 12, a conveyance stage 13 supporting a laminate 10 of at least one joined member and at least one solder material, and movable in the horizontal direction and the vertical direction, a cooling plate 15 for cooling the laminate via the conveyance stage, a hot plate 16 for heating the laminate via the conveyance stage, an active species gas introduction pipe 17, an inert gas introduction pipe 18, and an exhaust port 113, and further includes on the outside of the oven an AC or DC power supply (not shown) that is heating means for heating the metal wire by electrifying.

Description

  The present invention relates to a joining and assembling apparatus. In particular, the present invention relates to a joining / assembling apparatus that can be joined by a short-time soldering process to obtain a laminate including a solder joining layer with few bubbles in the solder joining layer.

  Conventionally, the following three methods are mainly performed as a method of manufacturing a power semiconductor device. In the first method, first, preliminary soldering is performed using a continuous furnace (tunnel furnace) in a reducing atmosphere, and solder is provided on the back electrode of the silicon chip. Subsequently, a silicon chip is soldered to the insulating substrate through the solder. Thereafter, wire bonding is performed. Then, a silicon chip soldered on an insulating substrate is soldered to a metal base made of copper or the like using a flux in the atmosphere.

  In the second method, the silicon chip and the insulating substrate are soldered using a continuous furnace in a reducing atmosphere. Thereafter, wire bonding is performed. Then, a silicon chip soldered on an insulating substrate is soldered to a metal base using a continuous furnace in a reducing atmosphere.

  In the third method, a silicon chip, an insulating substrate, and a metal base are soldered via flux-cored solder using a vacuum furnace in an inert atmosphere. Thereafter, wire bonding is performed.

  By the way, in a power semiconductor device such as a power module, since a large current flows, the heat generation amount of the silicon chip is as large as several tens to several thousand watts. Therefore, the power semiconductor device is required to have excellent heat dissipation characteristics. However, if air bubbles (voids) exist in the solder joint layer between the silicon chip and the insulating substrate, or the solder joint layer between the insulating substrate and the metal base, these bubbles prevent heat dissipation. This causes a significant decrease in the thickness of the semiconductor device and causes a breakdown of the semiconductor device. Therefore, it is important that bubbles do not exist as much as possible in the solder joint layer.

The reason why bubbles are generated in the solder joint layer is that residual oxides on the surface of the metal member constituting the laminate and dissolved gases such as carbon dioxide in the solder material remain as bubbles when the solder melts. Further, at the time of soldering, adsorbate adsorbed on the surface of a member to be joined such as solder or an insulating substrate, or tin oxide, copper oxide or nickel oxide is reduced, and H ₂ O generated thereby is gasified and remains as bubbles. This is also a cause. Another cause is that the gas generated by vaporization of the flux used during soldering and the flux itself remain in the solder joint layer.

  Therefore, in order to reduce air bubbles in the solder joint layer, in general, oxidation of the surface of the member to be joined is prevented to keep the surface clean, or a solder material having no dissolved gas or a solder material having good wettability is used. Measures such as doing are taken. In addition, measures such as optimizing the soldering profile, controlling deformation of the members to be joined, and soldering in a reduced pressure atmosphere are taken.

  Many proposals regarding soldering methods have also been made. For example, a processing container, means for controlling the atmosphere in the processing container and its pressure by generating a low oxygen concentration atmosphere by evacuation and high-purity gas introduction, and heating means provided in the processing container. A method of performing solder connection by heating a circuit board with a heating unit and controlling the pressure of the atmosphere in a processing container using a soldering apparatus provided is known (for example, see Patent Document 1).

  Furthermore, a laminated body composed of a metal base, a solder plate, an insulating substrate, a solder plate and a silicon chip is placed in a vacuum furnace, and after evacuating the furnace, the furnace is evacuated to a positive pressure hydrogen atmosphere. A method for manufacturing a semiconductor device is also known in which solder is heated and melted after reducing the surface of a member (see, for example, Patent Document 2).

  Also disclosed is a method of treating metal surfaces for dry soldering, where active molecular species are generated using a refractory metal filament grid, thereby removing oxides on the metal surface and then soldering. (For example, see Patent Document 3).

  In addition, examples of application to cleaning of solder before bonding with atomic hydrogen generated by a catalytic decomposition reaction are disclosed (for example, see Non-Patent Document 1 and Non-Patent Document 2). Furthermore, a lead-free solder alloy processing method is characterized in that a lead-free solder alloy mainly composed of tin is finely powdered and reduced and etched using atomic hydrogen generated by the hot wire method. (For example, see Patent Document 4).

Japanese Patent Application Laid-Open No. 8-22469 JP 2003-297860 A US Pat. No. 5,409,543 Japanese Patent No. 4991028

Surface Science Vol. 31, No. 4, pp. 196-201, 2010 Proceedings of the Japan Institute of Electronics Packaging, 22nd, pp.167-168 (2008)

  However, for example, in the method of Patent Document 1, a liquid is used for fixing the mounted component. In this case, it is necessary to perform a pretreatment (application of liquid) in a separate facility before putting into the soldering apparatus. There are disadvantages such as an increase in work time and work time. Further, in the method of Patent Document 2, the hydrogen reduction ability is effectively exhibited at about 300 ° C. or higher, but the reduction of the member to be joined and the solder is insufficient in the temperature range below that, and the joining property deteriorates. May end up. In order to improve the reduction capability of hydrogen gas, there is a method of further increasing the heating temperature, but there is a concern about thermal damage of the silicon chip.

  Since the invention disclosed in Patent Document 3 uses a continuous furnace and cannot achieve a sufficient degree of vacuum, the amount of atomic hydrogen produced is small and the reducing power for metal oxides and the like is not sufficient. Therefore, it is necessary to selectively collect atomic hydrogen on a workpiece using an apparatus for suppressing electrons, which causes a disadvantage that the apparatus becomes complicated and hydrogen and energy loss are large.

  Further, the method disclosed in Patent Document 4 is a method in which only a solder alloy is processed by a rotary drum type device prior to joining, and does not realize an efficient joining assembly including solder joining. The methods disclosed in Non-Patent Documents 1 and 2 are merely experimental methods and cannot be practically applied to efficient mass production of semiconductor devices.

  The present invention has been made in view of the above problems, and a laminated body of at least one member to be joined and at least one solder material is joined by a short-time soldering process, It is an object of the present invention to provide a joint assembly apparatus that can obtain a laminate including a solder joint layer with less bubbles.

  The present invention has been made to solve the above problems. That is, the present invention is a joining and assembling apparatus, which is a transfer stage that supports a laminated body of a metal wire, at least one member to be joined, and at least one solder material, and is movable in the horizontal direction and the vertical direction. A transport plate, a cooling plate and a hot plate that are spaced apart in the horizontal direction, the cooling plate capable of cooling the stack through the transport stage, and the stack through the transport stage. A heatable heat plate, an activated species production gas introduction pipe, an inert gas introduction pipe, and an exhaust port are provided in the vacuum furnace, and heating means for heating the metal wire is provided.

  In the joining and assembling apparatus, the metal wire is a metal selected from tungsten, molybdenum, platinum, nickel, rhenium, or an alloy made of at least one of them, and is heated to 1000 ° C. or higher to generate an active species generation gas. It is preferable that atomic hydrogen can be generated by thermal decomposition of In the joining and assembling apparatus, it is preferable that the metal wire is provided above the decompression furnace and above the hot plate. In the joining and assembling apparatus, it is preferable that the metal wire is provided above the hot plate so as to cover the entire hot plate. In the joining and assembling apparatus, it is preferable that a vertical distance between the metal wire and the transfer stage can be adjusted to 30 mm to 150 mm.

  In the joining and assembling apparatus, the active species generation gas introduction pipe includes a plurality of outlets that guide the active species generation gas to the metal wire, and from the outlet through the metal wire toward the hot plate, It is preferable that the active species product gas is ejected uniformly. Moreover, it is preferable that the joining assembly apparatus further includes a pressure monitoring device in the decompression furnace.

  According to another aspect of the present invention, there is provided a method for operating any one of the above-described joining and assembling apparatuses, wherein the inside of a vacuum furnace in which a laminate including at least one member to be joined and at least one solder material is charged. A primary depressurizing step for evacuating; a hot-wire heating step for generating atomic hydrogen by heating the metal wire after the primary depressurizing step to form a negative pressure hydrogen atmosphere in the decompression furnace; and the hot wire After the heating process, the inside of the vacuum furnace is set to a positive pressure hydrogen atmosphere, heated to a joining temperature to melt the solder material, and after the heating process, the inside of the vacuum furnace is maintained at the joining temperature. And a bubble removal step of removing the bubbles in the solder melt again in a vacuum atmosphere.

  In the air bubble removing step in the operation method of the joining and assembling apparatus, the hot wire heating step of generating atomic hydrogen by heating the metal wire by setting the inside of the vacuum furnace to a negative pressure hydrogen atmosphere is intermittently performed one or more times. It is preferable to include repeatedly.

  In the hot-wire heating step in the operation method of the joining and assembling apparatus, the hydrogen molecular gas may be supplied into the vacuum furnace so as to be supplied toward the laminated body after contacting the metal wire. preferable.

  It is preferable that the operation method of the bonding assembly apparatus further includes a re-reduction step in which the inside of the vacuum furnace is again brought into a positive pressure hydrogen atmosphere while maintaining the bonding temperature after the bubble removing step. In addition, it is preferable that the method further includes a cooling step of rapidly cooling the stacked body while keeping the inside of the decompression furnace in a positive pressure hydrogen atmosphere after the re-reduction step. Further, after the cooling step, a secondary decompression step for evacuating the inside of the decompression furnace, and after the secondary decompression step, the inside of the decompression furnace is changed to a positive pressure inert gas atmosphere, and then the decompression furnace is opened. It is preferable that a process is further included.

  In the operation method of the joining and assembling apparatus, it is preferable that the process from the hot wire heating process to the heating process is repeated a plurality of times. Alternatively, or in addition, it is preferable that the process from the bubble removal process to the re-reduction process is repeated a plurality of times.

  According to the joining and assembling apparatus according to the present invention, in particular, in addition to the conventional solder joining using only hydrogen gas, the activity having unpaired electrons generated by the decomposition of the active species product gas such as hydrogen gas by the metal wire. The seed provides a high oxide reduction effect. By providing the metal wire, in the joining and assembling apparatus according to the present invention, it is possible to realize the reduction of the solder below the solder melting temperature, the auxiliary heating of the joined member, and the oxide reduction of the joined member. . Then, by using the bonding assembly apparatus according to the present invention, for example, when manufacturing a semiconductor device, the solder bonding between the metal base and the insulating substrate and the solder bonding between the insulating substrate and an element such as a silicon chip are reduced. At the same time, it can be carried out in the furnace, and the bubbles in the solder are removed at that time, and the warp of the metal base caused by the joining of different materials is quickly removed. Then, within 10 minutes after the start of the operation of the joining and assembling apparatus, a semiconductor device having a solder joint layer with higher quality and higher reliability than the conventional one and excellent in heat dissipation can be obtained.

  In addition, according to the joining and assembling apparatus according to the present invention, it has a reducing effect in a lower temperature range, for example, 300 ° C. or less, and the amount of hydrogen gas or inert gas used is small, compared to the conventional case. There is no need to use flux. For this reason, it is possible to obtain effects such as shortening of processing time, high bonding quality, operation cost reduction effect, and environmental load reduction. Furthermore, by using the joining and assembling apparatus according to the present invention, it is possible to improve the joining characteristics of the laminated body, thereby eliminating the variation among a plurality of mass-produced products and stabilizing the quality. Have.

FIG. 1 is a diagram schematically illustrating a joining and assembling apparatus according to the present invention. FIG. 2 is a diagram showing a positional relationship between the metal wire 12 and the hot plate 16, and FIG. 2A is a view in the decompression furnace 11 when viewed from above the metal wire 12 toward the furnace bottom. FIG. 2B is a diagram showing a positional relationship between the metal wire 12 and the hot plate 16, and FIG. 2B is a diagram showing a positional relationship between the metal wire 12 and the hot plate 16 when viewed from the front of the decompression furnace. . FIG. 3 is a diagram schematically showing a configuration of a laminated body composed of a body to be joined and solder for performing soldering in the joint assembly apparatus according to the present invention. FIG. 4 is a chart showing an example of the temperature profile, the atmosphere and pressure in the chamber, the metal wire energization, and the processing operation in the operation method of the bonding assembly apparatus according to the present invention.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to the embodiments described below.

  The present invention relates to a joining and assembling apparatus according to an embodiment. FIG. 1 shows a schematic view of a joining and assembling apparatus according to the present invention. A joining / assembling apparatus according to the present invention includes a metal wire 12, a transfer stage 13, a cooling plate 15, a hot plate 16, an activated species generation gas introduction pipe 17, and an inert gas introduction pipe 18 in a decompression furnace 11. And mainly. In the present invention, the active species generating gas refers to a gas that can be catalytically decomposed by the metal wire 12 to generate an element having an unpaired electron having high reducibility. Such active species generating gas is not limited to a specific gas, but in the following description of the present embodiment, hydrogen gas is used as an example of the active species generating gas.

  The decompression furnace 11 is mainly composed of a furnace main body 110 and a lid body 111 which is covered with a packing 112 and keeps the inside of the furnace in an airtight state. The decompression furnace 11 includes a hydrogen molecular gas introduction pipe 17 for supplying a hydrogen molecular gas a into the furnace, an inert gas introduction pipe 18 for supplying an inert gas such as nitrogen gas b into the furnace, and an exhaust. A mouth 113 is provided. A hot plate 16 and a cooling plate 15 are spaced apart from each other at the bottom of the furnace body 110. The transfer stage 13 is configured to be able to go back and forth between the hot plate 16 and the cooling plate 15 by the transfer rail 14. The transfer stage 13 is also configured to be vertically movable by another mechanism (not shown).

  A metal wire 12 is attached to the upper part of the reduced pressure furnace 11, preferably the ceiling part of the reduced pressure furnace 11 constituting the lid 111 and above the hot plate 16. The metal wire 12 is connected to an AC or DC power supply source (not shown) outside the furnace, which is a heating means for heating the metal wire 12 by energization. As the AC or DC power supply source, a power supply device having a function of adjusting the power supplied to the metal wire 12 is provided outside the decompression furnace 11. At this time, the periphery of the metal wire 12 is a heat-resistant member and is configured to ensure insulation. This is because the periphery of the metal wire 12 is very hot and current and voltage are applied. Note that the metal wire 12 does not need to be attached to the ceiling portion of the decompression furnace 11 and is attached to the side wall portion of the decompression furnace 11 as long as the metal wire is located at a predetermined location described later. Alternatively, it may be supported by appropriate means from the bottom of the decompression furnace 11. Moreover, since the metal wire 12 can be deteriorated by heat or oxidation, the metal wire 12 is preferably attached to the decompression furnace 11 in a replaceable manner.

  The metal wire 12 is a linear metal member that can be heated to 1000 ° C. or higher, preferably 1500 ° C. or higher, more preferably 1600 ° C. or higher, and preferably 2000 ° C. or lower. Reducing atomic hydrogen (hydrogen atom) can be generated by catalytic cracking reaction. The metal wire 12 can be used repeatedly a plurality of times. For example, the metal wire 12 can be used repeatedly about 1000 times, but the number of repeated uses is not limited to a specific number. In this specification, the hydrogen molecular gas refers to a gaseous hydrogen molecule, and is used separately from atomic hydrogen generated by heating a metal wire. The material constituting the metal wire may be, for example, tungsten, tantalum, molybdenum, vanadium, platinum, thorium, zirconium, yttrium, hafnium, palladium, nickel, rhenium, or an alloy mainly composed of one or more of these, Although tungsten is preferably used, it is not limited to a specific metal as long as it has the above function.

  The metal wire 12 may have a diameter of, for example, 0.1 mm to 1.0 mm, preferably 0.3 mm to 0.8 mm, but is not limited to such a diameter. The metal wire 12 may be a single wire, or may be a double wire obtained by combining two or more metal wires, and a plurality of metal wires 12 that are single wires or double wires may be provided separately. In addition, such a single or double metal wire 12 may be formed in, for example, a zigzag shape (Z shape, U shape), a spiral shape (spiral shape), a mesh shape, a lattice shape, or a combination thereof as appropriate. It may be what. Although not limited to a specific shape, it is preferable to increase the surface area of the metal wire. This is because the contact area between the hydrogen molecular gas and the metal wire 12 is increased to generate more reducing atomic hydrogen.

  As for the mounting position of the metal wire 12, when the transport stage 13 is at the position B, the vertical distance between the stacked body 10 placed on the transport stage 13 and the metal wire 12 is within 150 mm, It is preferable to set it as 30 mm or more, and it is more preferable to set it as 50-100 mm. The vertical distance between the laminate 10 and the metal wire 12 is the center of the diameter of the metal wire 12 when the laminate 10 and the metal wire 12 are provided so as to be uniform as will be described later. And the distance from the upper surface of the laminate 10 to be heat bonded. Note that the vertical distance between the laminate 10 and the metal wire 12 can also be adjusted by the vertical adjustment mechanism of the transfer stage 13. In particular, it is configured so that a person skilled in the art can appropriately adjust the decomposition activity of the hydrogen molecular gas by the metal wire 12 and the temperature of the solder constituting the laminated body 10 under appropriate conditions described later. .

  In the decompression furnace 11, when the conveyance stage 13 exists in the position B or the position C, it is preferable that it is a positional relationship so that the distance of the metal wire 12 and the laminated body 10 which is a joining object becomes uniform. If the distance between the metal wire 12 and the laminated body 10 is non-uniform, the metal wire 12 is heated to a high temperature, and therefore, the radiant heat to the laminated body 10 is affected, and the temperature of the laminated body 10 may increase. Because. Further, the horizontal positional relationship between the metal wire 12 and the hot plate 16 in the decompression furnace 11 is preferably within the range covering the shape of the laminated body 10 to be joined, and the metal wire is preferably installed rather than one piece. It is more preferable to install the hot plate 16 in a range that covers the entire surface. This is because the hydrogen molecular gas decomposed by contact with the metal wire is generated radially in all directions of the metal wire, but attenuates according to the distance. FIG. 2A is a diagram showing a positional relationship between the metal wire 12 and the hot plate 16 when viewed from above the metal wire 12 in the decompression furnace 11 toward the furnace bottom, and FIG. These are figures which show the positional relationship of the metal wire 12 and the hot plate 16 at the time of seeing from the front of a decompression furnace. In addition, in order to avoid a figure becoming complicated, description of the conveyance stage 13 is abbreviate | omitted. Moreover, the relationship between the metal wire 12 and the hot plate 16 is not necessarily limited to this aspect, and may be installed in a range that covers at least the entire surface of the laminate 10 to be joined.

  In the illustrated embodiment, the metal wire 12 is attached only above the hot plate 16, but in addition to this, the metal wire 12 preferably surrounds the four sides of the hot plate 16, preferably with respect to the heating surface of the hot plate 16. The metal wire 12 may be attached vertically and parallel to the side wall of the vacuum furnace 11. Even in this case, the reduction effect by atomic hydrogen can be obtained by keeping the distance between the metal wire 12 and the laminated body 10 within the appropriate distance range.

  The cooling plate 15 may be one generally used in a typical soldering apparatus as long as it has at least a cooling surface and includes an arbitrary cooling mechanism capable of adjusting the cooling temperature and speed. As an example, the cooling plate 15 may be connected to a chiller 20 that circulates the cooling water d of the cooling plate 15 outside the furnace. In this case, an inlet / outlet (not shown) for circulating cooling water may be provided below the cooling plate 15, preferably at the bottom of the furnace body 110. In addition, the cooling plate 15 may cool a laminated body with another mechanism. The hot plate 16 is generally used in a typical soldering device as long as it has at least a heating surface and has an arbitrary heating mechanism capable of adjusting the heating temperature and speed. Good. For example, the hot plate 16 may be a heater or the like that can heat the laminated body 10 in the range of room temperature to 400 ° C. via the transfer stage 13.

  The cooling plate 15 and the hot plate 16 are spaced apart from each other at the bottom of the decompression furnace 11. The cooling plate 15 and the hot plate 16 are preferably installed with a distance of about 10 mm to 50 mm, for example. Further, it is preferable that the cooling surface of the cooling plate 15 and the heating surface of the hot plate 16 are installed so as to be located at substantially the same height from the bottom in the decompression furnace 11. Moreover, it is preferable that the cooling surface of the cooling plate 15 and the heating surface of the hot plate 16 have substantially the same area. In the illustrated embodiment, the cooling plate 15 and the hot plate 16 are installed separately from the bottom in the decompression furnace 11. This is because heat transfer from the cooling plate 15 and the hot plate 16 to the furnace body is avoided and efficient cooling or heating is performed. However, it can replace with such an installation mode, can arrange | position a suitable heat insulating material, and can also install the cooling plate 15 and the hot plate 16 in contact with the bottom part in the pressure reduction furnace 11. FIG.

  As an optional configuration (not shown), a partition plate functioning as a heat insulating wall may be provided between the cooling plate 15 and the heat plate 16. Further, a heat insulating wall may be provided on the outer periphery of the hot plate 16. With this configuration, it is possible to eliminate a non-uniform temperature portion in a region where the hot plate 16 and the cooling plate 15 are close to each other. With this configuration, a heat retaining effect can be achieved.

  The transfer stage 13 holds the stacked body 10 and functions as a moving unit for the stacked body 10. The transfer stage 13 and its driving mechanism may be those generally used in a typical soldering apparatus. The transfer stage 13 is configured to be movable in the horizontal direction between the hot plate 16 and the cooling plate 15 by the transfer rail 14. That is, it can move in the left-right direction in FIG. 1 and can move between positions A and B and between positions C and D. Further, it is configured to be movable in the vertical direction by a mechanism (not shown), and can move between positions A, B, C, and D. That is, it can also be moved in the vertical direction in FIG. The movable range in the vertical direction of the transfer stage 13 is preferably 0 mm to 50 mm. The movable range is preferably such that the vertical distance between the metal wire 12 and the transfer stage 13 can be adjusted within a range of 30 mm to 150 mm, preferably 50 mm to 100 mm. It is preferable that the conveyance stage 13 includes a detachable heat equalizing plate (not shown) thereon. The soaking plate may hold the laminated body 10 to be joined and can be used for soaking. For example, a soaking plate made of a carbon plate of 2 to 3 mm can be used.

  The hydrogen molecular gas introduction pipe 17 and the inert gas introduction pipe 18 are attached to the decompression furnace main body 111. The hydrogen molecular gas introduction pipe 17 and the inert gas introduction pipe 18 are connected to a hydrogen molecular gas supply source and an inert gas supply source (not shown) outside the furnace, respectively. 17 and an inert gas introduction pipe 18 are supplied. The hydrogen molecular gas introduction pipe 17 is not limited to the hydrogen molecular gas, but may be able to perform the function of introducing other active species generating gas alone or together with the hydrogen molecular gas. Other examples include, but are not limited to, halogen-containing gases such as ammonia, carbon tetrafluoride, and sulfur hexafluoride. Alternatively, another pipe (not shown) for introducing another active species product gas into the vacuum furnace 11 may be provided. The inert gas introduction pipe 18 is typically a nitrogen gas introduction pipe, but may be one that introduces another inert gas.

  The hydrogen molecular gas introduction tube 17 is installed above the metal wire 12, that is, so that the ejection portion is located between the lid 111 and the metal wire 12. Although illustration is omitted in order to avoid complication of the figure, the jet part of the hydrogen molecular gas introduction pipe is provided with piping in a range where the hydrogen molecular gas can be uniformly sprayed on the entire metal wire, and directed toward the metal wire 12. A blowout hole is provided in the opposite direction. In the case of the form shown in FIG. 1, specifically, the blowing holes are provided in the direction directly below. The blown-out hydrogen molecular gas passes through the metal wire 12, is decomposed into atomic hydrogen in the process, and can reach the stacked body 10. On the other hand, the inert gas introduction pipe 18 may be configured so that an inert gas such as nitrogen gas can be substantially uniformly introduced into the furnace 11 to replace the furnace atmosphere. The embodiment is not limited.

  The decompression furnace 11 may be any furnace body that can withstand the inside of the vacuum and can maintain airtightness, and its capacity and the like are not limited. The inside is preferably made of a material that is not easily deteriorated by atomic hydrogen or other active species, and can be made of, for example, stainless steel such as SUS304 or SUS316, stainless steel subjected to surface treatment, or an aluminum alloy. The exhaust port 113 of the decompression furnace 11 is used for evacuating the inside of the furnace, and also contains oxygen-containing compounds, sulfides, chlorides, and the like generated as a result of reduction of the constituent members of the laminate 10 in the furnace. Also serves as an outlet for hydrogen-containing compounds. A pressure reducing device 30 such as a vacuum pump is connected to the exhaust port 113.

  The decompression furnace 11 may further include a pressure measuring device and / or a temperature measuring device (not shown). By monitoring the total pressure in the furnace and optionally the hydrogen partial pressure using a pressure measuring device and / or the temperature of the members constituting the laminate 10 and the metal wire 12 using a temperature measuring device. By monitoring, the reaction in the reduced pressure furnace 11 can be adjusted.

  Such a joining and assembling apparatus is used for solder joining of a laminate of at least one member to be joined and at least one solder material. Typically, an insulated gate bipolar transistor (IGBT) formed by soldering an element such as a silicon chip on an insulating substrate such as a ceramic having a metal circuit board on a metal base. ) A joining and assembling apparatus used for manufacturing a semiconductor device represented by a power module such as a module or an IPM (Intelligent Power Module).

  Next, the joining and assembling apparatus according to the present invention will be described in terms of its operating method. Note that the operation method of the bonding assembly apparatus shown in FIG. 1 according to the present invention can also be understood as a manufacturing method of a laminated body using the bonding assembly apparatus, for example, a semiconductor device. Therefore, the following description also relates to a method for manufacturing a laminate using the joining assembly apparatus shown in FIG.

  That is, according to another aspect of the present invention, there is provided a method for operating a joining and assembling apparatus, wherein a vacuum furnace in which a laminate including at least one member to be joined and at least one solder material is charged is evacuated. After the primary decompression step, after the primary decompression step, the inside of the decompression furnace is set to a negative pressure hydrogen atmosphere, and the metal wire is heated to generate atomic hydrogen, and the hot wire heating step and the hot wire heating step Then, a heating step in which the inside of the vacuum furnace is set to a positive pressure hydrogen atmosphere and heated to a joining temperature to melt the solder material, and after the heating step, the inside of the vacuum furnace is again in a vacuum atmosphere while maintaining the joining temperature. A bubble removing step of removing bubbles in the solder melt, and optionally, a re-reduction step of bringing the inside of the vacuum furnace again into a positive pressure hydrogen atmosphere while maintaining the bonding temperature after the bubble removing step. Before the re-reduction step A cooling step of rapidly cooling the laminate while maintaining a positive pressure hydrogen atmosphere in the vacuum furnace, a secondary pressure reduction step of evacuating the pressure reduction furnace after the cooling step, and the pressure reduction after the secondary pressure reduction step And opening the decompression furnace after setting the inside of the furnace to a positive pressure inert gas atmosphere.

  In the joining and assembling apparatus according to the present invention, a target to be joined is a laminate of at least one member to be joined and at least one solder material, and in particular, a solder material between at least two members to be joined. It is an arbitrary laminated body via. Examples of the laminated body to be bonded include a semiconductor device, a power converter, an energization circuit, a printed wiring board, and the like, but are not limited thereto. In the following, the present invention will be described by taking the manufacture of a semiconductor device as an example, but the operation method of the joining and assembling apparatus according to the present invention is not limited to use in the manufacture of a specific device. Referring to FIG. 3, a laminate 10 to be joined and assembled typically includes an insulating substrate 2 laminated on a metal base 1 via an insulating substrate-metal base joining solder material 3, and A silicon chip 4 is laminated thereon via a silicon chip-insulating substrate bonding solder material 5. In FIG. 3, the silicon chip is described as an example of the semiconductor element. However, the semiconductor element to be bonded in the present invention is not limited to the silicon chip, and includes an SiC chip and a GaN chip. However, it is not limited to these.

  Typical members to be joined (joining base materials) constituting the collector electrode surface of the semiconductor element, the metal base, and the surface of the insulating substrate include gold (Au), copper (Cu), silver (Ag), nickel (Ni ), And / or alloys containing one or more of these as a main component, but are not limited thereto. As a typical solder material, lead-free solder, preferably lead-free solder having a melting point of about 190 to 290 ° C. can be used, more preferably lead-free solder having a melting point of about 210 to 290 ° C. can be used. . In a preferred embodiment, lead-free Sn-containing solder having a melting point of about 190 to 290 ° C. is used. Sn-containing lead-free solder includes Sn solder, Sn-Ag solder, Sn-Cu solder, Sn-Sb solder (melting point: about 190-290 ° C), Sn-Bi system (melting point: about 270 ° C), etc. Is included. More preferred is Sn-Ag solder. Sn-Ag solder includes Sn-Ag, Sn-Ag-Cu, Sn-Ag-Bi, Sn-Ag-Cu-Bi, Sn-Ag-Cu-In, Sn-Ag-Cu-S, and Sn -Ag-Cu-Ni-Ge and the like are included. More preferably, it is Sn-3.5Ag-0.5Cu-0.1Ni-0.05Ge solder or Sn-3.5Ag-0.5Cu solder. Similarly, Sn—Sb solder is also widely used for die bonding of power devices. Sn—Sb solder includes Sn—Sb, Sn—Sb—Ag, Sn—Sb—Ag—Cu, Sn—Sb—Ag—Cu—Ni, and the like. Preferably, Sn-5Sb, Sn-8Sb, Sn-13Sb, Sn-8Sb-3Ag, Sn-8Sb-3Ag-0.5Cu, Sn-8Sb-3Ag-0.5Cu-Ni 0.03-0.07 wt. %. Further, the solder material may be a solder plate or paste solder, and the form is not limited.

  As a preparation, as shown in FIG. 3, a plurality of members to be joined and a solder material are laminated to form a laminated body 10. Next, the laminated body 10 is placed on the transfer stage 13 in the decompression furnace 11. The stacked body 10 can be placed on the transfer stage 13 by an appropriate apparatus or by a person. In the batch type joining and assembling apparatus according to the present invention, the laminate 10 to be joined by one operation may be one as shown in the figure, or may be plural.

  FIG. 4 is a chart showing an example of the temperature profile of the solder constituting the laminated body, the energization of the metal wire, the atmosphere and pressure in the chamber, and the processing operation in the manufacturing method of the semiconductor device using the bonding assembly apparatus according to the present invention. It is. When the laminate 10 is placed on the transfer stage 13 and soldering is started according to the chart shown in FIG. 4, the decompression furnace 11 into which the laminate 10 is charged is sealed, and the decompression device 30 is activated to reduce the pressure in the furnace. Is started (timing T0). During the deaeration process, the transport stage 13 is in a position A in FIG. 1, which is in a standby state away from both the hot plate 16 and the cooling plate 15. In the operation at timings T0 to T8, it is preferable that the decompression device 30 continues the exhaust in the decompression furnace 11 in a state in which it is always operated.

After the primary depressurization step, a hot wire heating step is performed in which the inside of the depressurization furnace is set to a negative pressure hydrogen atmosphere to heat the metal wire in the depressurization furnace to generate atomic hydrogen (timing T1 to T2). Such a process can also be referred to as a primary reduction process in which the bonded member and the solder material are reduced by atomic hydrogen in a negative pressure hydrogen atmosphere. In the present specification, the negative pressure refers to a pressure lower than 101.3 × 10 ³ Pa. The flow rate of the hydrogen molecular gas is controlled by, for example, a mass flow controller.

  In the hot wire heating process, when the degree of vacuum in the vacuum furnace 11 reaches 1 to 10 Pa, for example, 5.7319 Pa, introduction of hydrogen molecular gas into the vacuum furnace 11 is started (timing T1). Further, the transfer stage moves to a position B in FIG. 1 that is above the hot plate 16 and is not directly heated by the hot plate 16. That is, the transfer stage moves to a place where the metal wire and the laminated body can ensure an appropriate positional relationship and distance in the hot wire heating process. When the pressure in the vacuum furnace 11 is 1 to 100 Pa, preferably 1 to 50 Pa, the metal wire 12 is heated by energization. In the chart of FIG. 4, the timing when the metal wire 12 is energized or the timing when it can be energized is indicated as “metal wire energization”. When the temperature of the metal wire 12 reaches, for example, 1600 ° C., the hydrogen molecular gas in the decompression furnace 11 is decomposed to be in the state of atomic hydrogen having a high reducing ability. In another embodiment, the transfer stage moves to a position heated by the hot plate 16, that is, a position C in FIG. However, the metal wire may be energized.

  A preferable heating temperature of the metal wire 12 varies depending on a metal material or an alloy material constituting the metal wire 12. For example, when tungsten is used as the metal wire, the heating temperature can be 1600 to 1800 ° C. The heating duration time (time to timing T1 and timing T2) of the metal wire 12 necessary for the reduction treatment of the surface of each member constituting the laminate 10 can be, for example, 10 seconds to 5 minutes, It can be 30 seconds to 120 seconds. A preferable heating time of the metal wire 12 varies depending on a metal material or an alloy material constituting the metal wire 12. For example, when tungsten is used as the metal wire, the heating time can be 30 seconds to 120 seconds. Further, the distance between the metal wire 12 and the laminated body 10 at this time is preferably 30 to 150 mm, and more preferably 50 to 100 mm. By setting the heating temperature of the metal wire 12, the energization time, and the distance between the metal wire 12 and the laminated body 10 to an appropriate range, contamination of the laminated body 10 due to the metal material constituting the metal wire 12 is prevented. be able to.

  During this time, the pressure in the furnace 11 is continued to be reduced while the flow rate of the hydrogen molecular gas is controlled so that the pressure in the vacuum furnace 11 is maintained at, for example, 1 to 100 Pa, preferably 10 to 50 Pa. As a result, substances generated as a result of the reduction reaction with atomic hydrogen and released into the atmosphere in the reduced pressure furnace, such as water sulfide and hydrogen chloride belonging to water and hydrogen compounds, are discharged outside the reduced pressure furnace 11 as exhaust c. Will be discharged. Further, during the period in which the metal wire 12 is energized, the members constituting the laminate 10 are simultaneously heated by the hot plate 16, and the temperatures of the solder materials 3 and 5 constituting the laminate 10 also depend on the members. However, it becomes about 100-200 degreeC. Thus, in the hot wire heating process, the reduction effect can be realized at a temperature lower than the temperature required for the conventional reduction with hydrogen molecular gas. In the hot-wire heating process, a halogen such as ammonia gas, carbon tetrafluoride, sulfur hexafluoride or the like is used instead of or in addition to the hydrogen molecular gas introduced into the furnace as an atomic hydrogen source. A contained gas can also be used.

At timing T2, energization to the metal wire 12 is stopped, and the metal wire heating is finished. Further, the transfer stage 13 moves from the position B to the position C. After the hot wire heating process, a heating process is performed in which the inside of the decompression furnace is set to a positive hydrogen atmosphere and heated to a bonding temperature to melt the solder material (timing T2 to T3). This step can also be referred to as a secondary reduction step of reducing at least the surface to be joined of each member of the laminate by setting the inside of the vacuum furnace to a positive pressure hydrogen atmosphere after the hot wire heating step. In the present specification, the positive pressure refers to a pressure greater than 101.3 × 10 ³ Pa. In the heating process, a hydrogen molecular gas is introduced into the decompression furnace 11 to make the inside of the furnace a positive pressure hydrogen atmosphere. The laminated body 10 is heated via the transfer stage 13 moved to the position C and is held in that state until the target joining temperature is reached. A constant temperature at timings T3 to T5 in FIG. 4 indicates the junction temperature. The temperature rising rate can be about 1 to 30 ° C. per second, and preferably about 5 to 10 ° C. per second.

  Here, the temperature of the hot plate 16 is preferably about 25 ° C. or more higher than the liquidus temperature of the solder. For example, Sn-3.5Ag solder having a liquidus temperature of 221 ° C. is used as the silicon chip-insulating substrate bonding solder material 5, and the liquidus temperature is 243 as the insulating substrate-metal base bonding solder material 3. In the case of using Sn-8Sb solder at ° C., the temperature of the hot plate 16 can be set to 270 to 280 ° C. in consideration of in-plane variation of the hot plate 16. Further, for example, Sn—Ag solder having a liquidus temperature of 221 ° C. is used as the silicon chip-insulating substrate bonding solder material 5, and the liquidus temperature is used as the insulating substrate-metal base bonding solder material 3. When using Sn-3.0Ag-0.5Cu solder at 219 ° C., the temperature of the hot plate 16 is 245-250 ° C. according to the above description. However, considering that the effect of reducing power of hydrogen molecules is clearly exhibited at 250 ° C. or higher, the heating temperature of the hot plate 16 for sufficiently exhibiting the reducing power is 290 ° C. or higher and 350 ° C. The following is preferable. When the semiconductor element is a SiC chip, the heating temperature of the hot plate 16 may be about 290 ° C. to 500 ° C., for example, but is not limited to a specific heating temperature.

  In the temperature raising process (timing T2 to T3) until the target joining temperature is reached, the pressure in the decompression furnace 11 is positive, so that the hydrogen molecular gas penetrates into the gaps between the members of the laminate 10. It becomes easier and the reduction action by the hydrogen molecular gas proceeds. Therefore, the reduction of each surface of the insulating substrate-metal base bonding solder material 3, the silicon chip-insulating substrate bonding solder material 5, the insulating substrate 2 and the metal base 1 is promoted, and the surface to be bonded, for example, the surface for wire bonding. The wettability such as is secured. In addition, the solder materials 3 and 5 are melted, and bubbles generated at that time are filled with hydrogen molecular gas, whereby the bubbles are activated. That is, the gas component in the bubbles is replaced with hydrogen, and is sufficiently activated by the bubble removal process and the re-reduction process at subsequent timings T3 to T5. While the solder materials 3 and 5 are melted, the oxygen concentration in the vacuum furnace 11 is kept at, for example, 30 ppm or less, preferably 10 ppm or less, and the dew point is kept at -30 ° C. or less, preferably -50 ° C. or less. It is.

  After the heating step, when the constituent members of the laminated body 10 reach the target joining temperature, the bubble removing step is performed in which the inside of the decompression furnace is again in a vacuum atmosphere while the joining temperature is maintained, and the bubbles in the solder melt are removed. (Timing T3 to T4). In the bubble removal step, the decompression in the decompression furnace 11 is started again (timing T3). Then, after the degree of vacuum in the decompression furnace 11 reaches 10 Pa, for example, the decompression is continued for 30 seconds to 1 minute, for example. Thereby, the degree of vacuum in the vacuum furnace 11 reaches approximately 1 Pa. By continuing the pressure reduction, both of the bubbles generated due to insufficient wetting between the solder material and the member to be joined and the bubbles generated by the dissolved gas contained in the solder material are almost removed. Here, the duration of decompression (T3 to T4) is set to 30 seconds to 1 minute because when bubbles are suddenly decompressed, bubbles are generated when the bubbles are rapidly discharged to the outside. This is because there is a concern that the solder scatters and the solder scatters on the solder balls and the outer peripheral portion in the same manner as the action of flipping, and even if the decompression is continued for more than 1 minute, no further bubble removing effect can be obtained. Because.

  During the period from timing T3 to T4, only the decompression may be performed without introducing the hydrogen molecular gas into the decompression furnace 11. Alternatively, after the pressure reduction is started at timing T3, the degree of vacuum is once increased to, for example, about 1 to 10 Pa, and then the heating wire heating process may be performed once or more again by timing T4. That is, after supplying hydrogen molecular gas into the furnace and setting the pressure in the furnace to 1 to 100 Pa, preferably 10 to 50 Pa, the metal wire 12 is energized to perform reduction treatment with atomic hydrogen. At this time, between the timings T3 and T4, the metal wire 12 may be energized only once, or energization and energization stop may be set as one set, and a plurality of sets may be repeated. That is, the hot wire heating process in which the inside of the vacuum furnace 11 is heated to a negative pressure hydrogen atmosphere to heat the metal wire 12 and generate atomic hydrogen may be repeated one or more times. When the energization and the energization stop are repeated as one set, the furnace pressure becomes 1 to 100 Pa, preferably 10 to 50 Pa at the timing when the metal wire 12 is energized, and is close to vacuum at the timing when the energization is stopped. The hydrogen flow rate and the furnace pressure can be controlled so that the pressure is, for example, 1 to 10 Pa. The energization time can be 10 seconds to 5 minutes as described above, and the energization stop time is preferably 30 seconds to 120 seconds. When energizing the metal wire 12 and stopping energization are repeated, the number of repetitions is preferably 2 to 5, but is not limited to a specific number. In FIG. 4, “metal wire energization” from timing T3 to T4 does not necessarily require that energization is continued in this section, but indicates that energization is possible in this section. .

  After the bubble removal step, a re-reduction step is performed again (timing T4 to T5) with the inside of the decompression furnace again set to a positive pressure hydrogen atmosphere while maintaining the bonding temperature. This process is a primary reduction process with atomic hydrogen at timings T1 to T2, a secondary reduction process with hydrogen molecular gas at timings T2 to T3, and is also referred to as a tertiary reduction process. In the re-reduction step, first, hydrogen molecular gas is again introduced into the furnace (timing T4). After the pressure in the vacuum furnace 11 reaches a positive pressure, the hydrogen molecular gas is further introduced continuously for about 30 seconds to 1 minute or more for about 5 minutes (T4 to T5). However, this time is not limited to this time because it varies depending on the size of the laminate to be heated. The reason for continuing the introduction of the hydrogen molecular gas is the tunnel that remains in the solder materials 3 and 5 when the bubbles in the solder materials 3 and 5 are removed from the solder materials 3 and 5 when the decompression is continued for 1 minute as described above. This is because the pores (the traces through which bubbles have passed) are blocked by the reducing action of the hydrogen molecular gas. That is, since the bubbles in the solder materials 3 and 5 are filled with the gas of the oxidizing component, the solder part that comes into contact with the bubbles passes through and is oxidized. For this reason, the solder in the passage of bubbles may not get wet, and tunnel-shaped open bubbles may remain. By performing the re-reduction step at timings T4 to T5, the open molecular bubbles are filled with hydrogen molecular gas, whereby the oxidized inner surface is reduced, the solder wettability is improved, and the open bubbles are filled with the solder. It will be.

  Another reason for continuing the introduction of the hydrogen molecular gas is that the surface tension of the solder material 5 is reduced by the reduction by the hydrogen molecular gas and the heating and holding by the hot plate 16, thereby stabilizing the solder fillet shape. This is to improve the solder crack generation life. If the solidification of the solder material is started immediately after depressurization in the furnace without continuing the introduction of the hydrogen molecular gas, the solder fillet shape becomes non-uniform due to the high surface tension of the solder material, resulting in a temperature cycle. In some cases, the life of solder cracks due to such factors is shortened. In order to reduce the surface tension of the solder material 5, at timings T <b> 4 to T <b> 5, the solder material 5 is heated and held at the joining temperature, the time during which the solder material 5 is exposed to the hydrogen molecular gas is lengthened, or a combination thereof is possible. That's fine. However, even if the introduction of hydrogen molecular gas is continued for longer than 1 minute, there is not much difference in the effect of filling the holes where the bubbles have passed and the effect of stabilizing the solder fillet shape. The duration is preferably 30 seconds to 1 minute.

  In an embodiment of the present invention, the heating process (T1 to T3) from the hot wire heating process may be repeated a plurality of times. That is, the operation at the timings T1 to T3 may be one cycle, and T1 to T3 may be repeated for a plurality of cycles, for example, 2 to 5 cycles. By repeating T1 to T3 for a plurality of cycles, the metal surface can be efficiently modified before the solder is melted.

Or you may repeat the bubble removal process and re-reduction process of timing T3-T5 in multiple times, without repeating operation of said timing T1-T3, or with repetition of operation of T1-T3. As an example, when a large area substrate is bonded or when bubbles are difficult to escape, the operations of the bubble removal process and the re-reduction process of T3 to T5 are set as one cycle, and T3 to T5 are performed in multiple cycles, for example, 2 to 5 cycles. It is good also as a structure to repeat. This is because by repeating the pressure reduction and pressurization in this manner, the molten solder is oscillated and the bubbles are easily removed, so that the bubble removal effect is obtained. However, when the number of repetitions of the bubble removal process is up to 5, the bubble rate decreases as the number increases. However, even if the number of repetitions is 6 cycles or more, no further effect can be obtained.
In addition to these repeating operations, T1 to T5 can be repeated a plurality of times.

  After the re-reduction step, a cooling step is performed in which the stacked body 10 is rapidly cooled while the pressure-reducing furnace 11 is kept in a positive-pressure hydrogen atmosphere (timing T5 to T6). In the cooling process, the transfer stage 13 moves on the rail 14 and is moved from the hot plate 16 to the cooling plate 15 (position D). Thereby, cooling of the laminated body 10 is started (timing T5). The laminated body 10 is cooled at a rate of 300 ° C. per minute, for example. At this time, a positive pressure hydrogen atmosphere is maintained in the furnace.

  The temperature and cooling time of the cooling plate 15 are selected in consideration of the cooling rate (solidification rate) of the solder. That is, in the present embodiment, since the silicon chip 4, the insulating substrate 2, and the metal base 1 having different thermal expansion coefficients are soldered at the same time, the metal base 1 having the largest thermal expansion coefficient when the soldering is completed. May be warped so as to be convex toward the insulating substrate 2 side. Due to the influence, the laminated body 10 joined through the solder joint layer may be warped by about 0.3 mm at the maximum. If this warpage is carried over to the next wire bonding step, it will cause the occurrence of defective electrical characteristics. Therefore, it is necessary to remove the warpage before wire bonding. For this purpose, the solder joint layer between the insulating substrate 2 and the metal base 1 may be creeped in a short time.

  In order to increase the creep rate, the cooling rate is preferably 250 ° C. or more per minute, for example, 300 ° C. per minute. In Japanese Patent Application Laid-Open No. 2003-297860 by the present applicant, if the cooling rate is 250 ° C. or more per minute, the warp of the metal base 1 is in the range of 0 to −0.1 mm within 24 hours (“−” indicates insulation). It is shown that the projection is convex on the substrate 2 side, and the adverse effect on the wire bonding can be eliminated. In other words, when the cooling rate is less than 250 ° C. per minute, the warp of the metal base 1 cannot be sufficiently returned, which may adversely affect wire bonding. Further, if the solder creep is accelerated and the residual stress of the laminated body 10 after joining is removed in the previous step as much as possible, the deformation of the metal base 1 can be stabilized. Accordingly, the temperature and cooling time of the cooling plate 15 are selected so that the cooling rate of the solder is 250 ° C. or more per minute.

  Then, after the cooling step, a secondary pressure reducing step for evacuating the inside of the pressure reducing furnace is performed (timing T6 to T7). In the secondary decompression step, when the temperature of the stacked body 10 reaches, for example, 50 to 60 ° C., the exhaust of hydrogen in the decompression furnace 11 is started (timing T6).

  After the secondary decompression step, the inside of the decompression furnace is set to a positive nitrogen atmosphere, and then the decompression furnace is opened (timing T7 to T8). In such a process, when the degree of vacuum in the decompression furnace 11 becomes 1 to 10 Pa, for example, due to the exhaust of hydrogen, nitrogen gas is introduced into the decompression furnace 11 (timing T7). Then, after the inside of the decompression furnace 11 is replaced with nitrogen gas and the hydrogen concentration in the furnace reaches the explosion limit or less, the decompression furnace 11 is opened (timing T8). A series of operations at timings T0 to T8 in FIG. 4 can be completed within approximately 15 minutes, depending on the number of repeated steps. By this series of operations, a semiconductor device having a high-quality solder joint layer free of bubbles can be obtained. Note that here, a nitrogen atmosphere has been described as an example, but the present invention is not limited to nitrogen, and an inert gas atmosphere can be formed using any inert gas.

  By the way, for example, when the element such as the silicon chip 4 has a size of 5 mm square or less, the size of the silicon chip-insulating substrate bonding solder material 5 is also 5 mm square or less. As described above, if the size of the silicon chip and the solder material is extremely small, it takes time to prepare for soldering, the alignment between the silicon chip 4 and the solder material 5 is not sufficient, and a bonding failure occurs. There is a risk. Therefore, when the silicon chip 4 having such a size is to be soldered, preliminary soldering is performed using the joining and assembling apparatus according to the present invention, and the silicon chip 4 is insulated in advance on the back surface of the silicon chip 4, for example, the collector electrode surface. It is desirable to provide the board bonding solder 5. In particular, when using solder that contains Sn, which is easy to oxidize, and does not contain Pb as the solder material, the oxygen concentration in the vacuum furnace 11 is an extremely low oxygen atmosphere of several tens of ppm or less. The surface oxide film can be reduced as much as possible. Similarly, the silicon chip 4 can be soldered to the insulating substrate 2 through the solder provided on the back surface of the silicon chip 4 by preliminary soldering using the joining and assembling apparatus according to the present invention. Note that the preliminary soldering is not performed only on the element such as the silicon chip 4 having a small size as described above, but is performed on an arbitrary element such as an element such as the silicon chip 4 having a larger size. Even in such a case, the semiconductor device manufacturing method according to the present invention can be effectively applied.

  The semiconductor device manufacturing apparatus and the operation method thereof according to the present invention can be preferably used in manufacturing power modules such as IGBT modules and IPMs.

DESCRIPTION OF SYMBOLS 1 Metal base 2 Insulating substrate 3 Insulating substrate-metal base joining solder material 4 Silicon chip 5 Silicon chip-insulating substrate joining solder material 10 Laminated body 11 Depressurization furnace 110 Furnace body 111 Lid body 112 Packing 113 Exhaust port 12 Metal wire 13 Transport stage 14 Transport rail 15 Cooling plate 16 Hot plate 17 Hydrogen gas introduction tube 18 Inert gas introduction tube 20 Chiller 30 Decompression device a Hydrogen molecular gas b Nitrogen gas c Exhaust d Cooling water

Claims (15)

Metal wire,
A transport stage that supports a laminate of at least one member to be joined and at least one solder material, the transport stage being movable in a horizontal direction and a vertical direction;
A cooling plate and a hot plate that are installed separately in the horizontal direction, the cooling plate capable of cooling the stacked body via the transfer stage, and the hot plate capable of heating the stacked body via the transfer stage When,
An activated species production gas introduction pipe;
An inert gas introduction pipe;
A joining and assembling apparatus comprising an exhaust port in the decompression furnace and a heating means for heating the metal wire.   The metal wire is a metal selected from tungsten, molybdenum, platinum, nickel, rhenium, or an alloy composed of one or more thereof, and is heated to 1000 ° C. or higher to thermally decompose the active species product gas and atomize The joining and assembling apparatus according to claim 1, wherein hydrogen is produced.   The joining and assembling apparatus according to claim 1, wherein the metal wire is provided in an upper part of the decompression furnace and above the hot platen.   The joining assembly apparatus according to claim 3, wherein the metal wire is provided above the hot plate so as to cover the entire hot plate.   The joining and assembling apparatus according to claim 1, wherein a vertical distance between the metal wire and the transfer stage can be adjusted to 30 mm to 150 mm.   The activated species product gas introduction pipe includes a plurality of outlets for guiding the activated species product gas to the metal wire, and the activated species product gas is uniformly distributed from the outlet to the hot plate via the metal wire. The joining assembly apparatus according to any one of claims 1 to 5, wherein   The joining assembly apparatus according to any one of claims 1 to 6, further comprising a pressure monitoring device in the decompression furnace. An operation method of the joining assembly device according to any one of claims 1 to 7,
A primary depressurization step of evacuating the inside of the depressurization furnace into which the laminate including at least one member to be joined and at least one solder material is charged;
After the primary decompression step, the inside of the decompression furnace is set to a negative pressure hydrogen atmosphere, the metal wire is heated to generate atomic hydrogen, a hot wire heating step,
After the hot-wire heating step, the heating step of melting the solder material by heating the inside of the vacuum furnace to a positive pressure hydrogen atmosphere and heating to a bonding temperature;
After the heating step, the operation method of the joining and assembling apparatus includes a bubble removing step of removing the bubbles in the solder melt by making the inside of the decompression furnace a vacuum atmosphere again while maintaining the joining temperature.   9. The bubble removal step includes a hot wire heating step in which the metal wire is heated in a vacuum atmosphere in the vacuum furnace to generate atomic hydrogen, which is intermittently repeated one or more times. The operation | movement method of the joining assembly apparatus of description.   The joining assembly according to claim 8 or 9, wherein in the hot wire heating step, a hydrogen molecular gas is supplied into the decompression furnace so as to be supplied toward the laminated body after contacting the metal wire. How the device works.   The operation method of the joining / assembling apparatus according to any one of claims 8 to 10, further comprising a re-reducing step in which the inside of the decompression furnace is again brought into a positive-pressure hydrogen atmosphere while maintaining the joining temperature after the bubble removing step.   The operation method of the joining / assembling apparatus according to claim 11, further comprising a cooling step of rapidly cooling the stacked body with the inside of the decompression furnace in a positive pressure hydrogen atmosphere after the re-reduction step. After the cooling step, a secondary pressure reducing step for evacuating the inside of the vacuum furnace;
The operation method of the joining and assembling apparatus according to claim 12, further comprising a step of opening the decompression furnace after making the inside of the decompression furnace a positive pressure inert gas atmosphere after the secondary decompression process.   The operation method of the joining and assembling apparatus according to any one of claims 8 to 13, wherein the heating wire heating process to the heating process are repeatedly included a plurality of times.   The operation method of the joining / assembling apparatus according to claim 8, wherein the process from the bubble removal process to the re-reduction process is repeated a plurality of times.

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