DIFFUSION SOLDERING DEVICE AND / OR SINTERING DEVICE, PRESSING TOOL AND SYSTEM FOR JOINING COMPONENTS OF AT LEAST AN ELECTRONIC ASSEMBLY

Description

[0001] The present invention relates to a diffusion soldering device and / or sintering device for joining components of at least one electronic assembly by means of diffusion soldering and / or pressure sintering, comprising an upper tool and a lower tool, between which the assembly is received, wherein the upper tool has at least one pressure cushion filled or fillable with a fluid or a displaceable medium, the internal pressure of which is variable, and at least one, in particular several, plungers in operative connection with the pressure cushion, which are arranged to transmit a pressing force generated by an increase in pressure in the pressure cushion to the assembly and of thermal energy. STAND DER TECHNIK

[0002] Using diffusion soldering and / or sintering devices of this type, a solid workpiece can be produced from a so-called green body, which consists of a fine- or coarse-grained material or mixture of materials, under the influence of heat and pressure. Such diffusion soldering and / or sintering devices serve to mechanically, electrically, and thermally connect components of electronic assemblies. For example, a diffusion soldering and / or sintering device of this type can be used to connect semiconductor components, such as high-performance switching elements or semiconductor assemblies, and a base body, such as a circuit board, a heat sink, or the like, by means of diffusion soldering or pressure sintering.In the field of power electronics, it has become established to provide so-called mold modules, in which various electronic circuits and semiconductor components can be integrated and which are generally equipped with contact pins for connection to an electronic system. These mold modules can be used for encapsulating electronic components, whereby wire-bonded, soldered, or glued microelectronic assemblies can be protected with a thermomechanically adapted, robust encapsulation material.

[0003] In diffusion brazing, atoms of the solid base material mix with atoms of the liquid brazing alloy under pressure. This creates an alloy zone that forms a metallurgical bond between the base material and the brazing alloy. In a variant of pressure sintering, low-temperature pressure sintering, two or more components, particularly electronic components and substrates, can be electrically and / or thermally connected to one another using a joining material, whereby the joining material is sintered. A corresponding device and method are known, for example, from WO 2014 / 135151 A2.

[0004] Currently, joining methods are being developed that represent a combination of a diffusion soldering process and a sintering process, whereby the joining agents used can utilize a combination of a diffusion solder and a sintering paste.

[0005] The required pressing pressures can be up to 650 bar, and temperatures of up to 350 °C are possible.

[0006] Diffusion soldering and / or sintering devices of this type are frequently used in automatic sintering plants, especially automatic multi-chamber sintering plants.

[0007] The sintering or diffusion soldering of the electronic assemblies themselves is achieved by temperature control of the assemblies or their components and the application of pressure mediated by the upper and lower dies. For example, the temperature required for bonding and diffusion in low-temperature pressure sintering with silver is typically between approximately 130°C and 250°C to 300°C, and at a pressure of up to 30 MPa, it takes about 5 to 10 minutes.

[0008] To ensure that the sintered material introduced between the components during pressure sintering forms a layer with as few pores as possible and is parallel, thus guaranteeing a mechanically stable, especially shear-resistant, bond and the desired electrical and thermal conductivity, the bonding layer is compacted by pressure before and during the diffusion process. Towards the end of the sintering process, the pressure and temperature are reduced.

[0009] One challenge lies in applying the pressing force required for diffusion soldering or sintering to the assemblies as uniformly as possible, so that the components of the assemblies are not subjected to local or temporary pressure peaks. Avoiding such local pressure peaks is particularly challenging when diffusion soldering or sintering assemblies in which several electronic components of varying heights are arranged on a substrate or workpiece carrier. For the purposes of this invention, electronic components are understood to include semiconductor components and electronic circuit assemblies, as well as passive electrical components such as cooling elements like cooling plates, printed circuit boards (PCBs), or connection elements such as power pins, e.g., copper pins. An assembly is such a component or a combination of such electronic components.

[0010] In the following, we will mostly refer to pressure sintering; however, this also includes all aspects of diffusion brazing that can be implemented in a similar or comparable way to a pressure sintering process with regard to temperature and pressure application during the joining process.

[0011] In order to enable the most uniform distribution of the pressing force or pressure possible, it was proposed in the prior art to use pressure cushions for generating the pressing pressure, which are in operative contact with several punches of different heights and which transfer the pressing force from the pressure cushion to the assemblies.

[0012] A sintering device of this type is described in DE 10 2007 047 698 B4. Another sintering device with a pressure pad, but without a punch, is disclosed in DE 102014 114 095 B4.

[0013] EP 3 454 364 A1 relates to devices for encapsulating or sintering semiconductor elements and shows an upper tool and a lower tool with an assembly arranged between them. The upper tool includes a pressure application unit in the form of a fluid-fillable pressure pad with variable internal pressure, which interacts with spacers to transmit the pressing force generated by increasing the pressure in the pressure pad to the assembly. The upper tool has a guide frame with guide channels in which the spacers can be moved axially along the pressing force with lateral tilting play. The pressure medium is contained in a pressure chamber, with a diaphragm, a flexible membrane, positioned between the pressure medium and the spacers. This diaphragm covers the guide channels to seal the spacers from the pressure pad. The pressure chamber is connected to a fluid supply to increase the pressure.

[0014] WO 2018 / 122 795 A1 describes a sintering device of the same type, in which the punches are arranged directly in a cylinder without a guide frame, thus eliminating the need for a separate guide frame.

[0015] German patent application DE 10 2017 216 545 A1 describes a sintering device comprising an upper tool and a lower tool for sintering electronic assemblies. A pressure pad includes a cavity and a membrane and is pressurized by a fluid source with variable internal pressure. The pressure pad is connected via the membrane to a press ram for transmitting the pressing force, which is axially guided in a guide frame.

[0016] WO 2016 / 050 466 A1 concerns a sintering device of a similar type, in which a receptacle for a pressure pad is provided in a cylinder-piston arrangement.

[0017] A disadvantage of conventional diffusion brazing or sintering devices is that the pressing pressure or force often cannot be applied uniformly or parallel enough to the assemblies being sintered or diffusion brazed. This can lead to pressure peaks or gradients, as well as parallel sintered layers, which can locally stress individual components or prevent the formation of uniform bonded layers with consistent mechanical, electrical, and / or thermal properties at every point. Another disadvantage of known diffusion brazing or sintering devices can be that the application of the pressing force is not simultaneous or parallel, i.e.,It can happen that the pressing pressure builds up earlier in certain areas than in others, so that the pressing time can vary spatially, which makes controlled process management difficult and can therefore also lead to quality fluctuations. Furthermore, a disadvantage of conventional diffusion brazing or sintering devices with guided press rams is that complex sealing membranes or seals to a pressure chamber or pressure pad must be provided, which are prone to wear and do not allow for quick and cost-effective changeover of the press tool. BESCHREIBUNG DER ERFINDUNG

[0018] The object of the invention is to provide a diffusion soldering and / or sintering device which is designed to generate a spatially and temporally homogeneous pressing force on at least one, in particular a plurality of, assemblies.

[0019] The problem is solved by a diffusion soldering and / or sintering device having the features of claim 1. Advantageous embodiments of the diffusion soldering and / or sintering device are specified in the dependent claims.

[0020] The present invention provides that the upper tool has a guide frame in which the punch(es) are guided axially and displaceably along the direction of the pressing force. The punch(es) are guided in the guide frame in a sealed manner relative to the pressure pad. Thus, the guide frame and the sealed punch(es) guided therein seal the pressure pad against the pressing surface and prevent damage to the pressure pad. The axial guidance of the punch(es) ensures that the pressing force required for diffusion brazing or pressure sintering is transferred with the necessary homogeneity, both spatially and temporally, from the pressure pad to the assembly to be sintered or brazed. The punch(es) can be heated or enable rapid transfer of heat energy to the assembly to be sintered or brazed.The transmission can be selective and faster than previously possible with a large-area single stamp, especially with a single stamp using a pressure pad, particularly a silicone pad. The stamp(s) are thus guided in or against the direction of the pressing force. The stamp(s) can exert selectively adjustable pressing forces, at least through their geometric design, and are directly mechanically coupled to one another.

[0021] The sealing can be achieved either by a sealing membrane between the pressure pad and the guide frame or the top of the punch(es), or by a sealing element of the punch(es) within the punch guide in the guide frame.

[0022] The pressure pad preferably comprises a volume enclosed by a flexible, pliable, and / or stretchable pad membrane and filled with an incompressible or compressible fluid or a displaceable medium such as a gel or similar substance. The fluid or displaceable medium can be present within the pressure pad and / or be supplied or replenished from the outside before or during a diffusion soldering and / or sintering process, for example, via a hydraulic feed. The compensating medium contained within the pressure pad volume is typically a fluid or another viscous medium, i.e., a displaceable substance such as an elastomer, for example, silicone, thermal oil, thermal paste, or thermal grease. Hydraulic oil, silicone, or perfluoropolyether (PFPE) can be used as the fluid, for example.For example, the PFPE designated as Galden HS260 has a boiling point of 260 °C and can be pumped out using a regularly available vacuum pump in the event of a leak in the pressure cushion.

[0023] The pressure pad can also be filled with gas or powder, or be made of a foil such as graphite foil, or of a soft metal, particularly softer than iron, such as aluminum, lead, gold, indium, copper, platinum, silver, zinc, or tin. A thin elastic foil like graphite foil can also be used to ensure parallelism between the upper and lower dies. The fluid can also be a gas, such as nitrogen. Furthermore, the use of other gaseous substances, especially water vapor, is also possible. The fluid can preferably be a gas or another displaceable medium, such as PFPE (Galden), silicone, CO₂, argon, nitrogen, helium, Igumix (a gas mixture), and mixtures or combinations of elastomers, oils, greases, and / or gases.The volume can be self-contained or have an access point through which fluid can be added or removed, as described below in connection with a preferred embodiment.

[0024] Preferably, the pressure pad can be designed as a silicone pad.

[0025] According to an advantageous embodiment of the invention, the upper tool has at least one pressure unit with a receptacle for the pressure pad. The receptacle, which preferably encloses the pressure pad from several sides, holds the pad in both a working position and a rest position in which no pressing force is exerted on the assembly and, with stable support for the pressure pad, ensures a homogenization of the pressing force. Several pressure units can be provided, particularly if each pressure unit accommodates a pressure pad for an individual punch, each individual punch having a relatively large punching surface, as is the case, for example, with soft punches. Unlike hard punches, soft punches consist of a soft material such as silicone or a soft metal on the punching surface.

[0026] According to a further advantageous embodiment, the pressure unit has an opening facing the lower tool, which is covered by the guide frame, with the pressure pad resting on the guide frame. The opening thus allows the pressure pad to come into operative contact with the punch(es) guided in the guide frame. At the same time, the guide frame provides additional support, supplementing the support provided by the receptacle in the pressure unit.

[0027] According to a further advantageous embodiment, the pressure unit comprises a cylinder and a piston movably mounted therein, wherein the cylinder and the piston define the receptacle for the pressure pad such that the volume of the receptacle can be changed by moving the piston. Thus, immersing the piston in the cylinder reduces the volume of the receptacle, thereby increasing the pressure within the pressure pad. This pressure increase generates the pressing force required for diffusion brazing or pressure sintering. The cylinder can also serve as a guide frame if a single punch or a so-called multi-punch, as explained below, is used.

[0028] As the piston moves out of the cylinder, the volume of the receptacle increases again and the pressure in the pressure pad decreases, thus reducing the pressing force.

[0029] In this context, it is preferred if the opening is provided in the piston. The piston is thus located on a side of the pressure unit facing the lower tool and is, for example, designed as a ring piston.

[0030] According to a further advantageous embodiment, the upper and lower tools are movable relative to each other along the direction of the pressing force, with the piston being moved into the cylinder when the upper tool contacts the lower tool or a workpiece carrier resting on the lower tool. In this configuration, the pressing force is generated indirectly, namely by a relative movement between the upper and lower tools. This relative movement can be effected by suitable means, for example, by hydraulic or spindle drives. The displacement of the piston relative to the cylinder is therefore indirect or passive; a direct drive to effect this relative movement between the piston and cylinder is not required. The piston is preferably connected to the guide frame.Thus, the pressure increase in the pressure cushion only occurs when the upper tool comes into contact with the lower tool or a workpiece carrier mounted on it, which carries the electronic assemblies to be sintered.

[0031] According to a further advantageous embodiment of the invention, the pressure pad is connected or connectable to a fluid source for supplying fluid to the pressure pad, wherein the pressure increase is achieved by the supply of fluid. The fluid can be a liquid or a gas. The fluid source can be heated and / or cooled, so that the supplied fluid can be used for heating and cooling. In particular, the fluid source can comprise a heat exchanger, especially a flow-through heat exchanger, for temperature control of the fluid. It is conceivable that liquid metal could also be used as the fluid. Fluids or displaceable metals can, for example, be poured in while hot, then solidify, and after installation in the sintering system, be liquefied by heating the sintering system and thus remain liquid or be liquefied. For example, solder suitable for the sintering process temperature can be used for this purpose.

[0032] Alternatively or additionally to the change in volume of the intake described above by moving the piston within the cylinder, the pressure increase in the pressure cushion can also be achieved by supplying additional fluid to the pressure cushion. The fluid source can be, for example, a pump or another suitable reservoir capable of supplying the fluid. The fluid can be in liquid or gaseous form; for instance, PFPE (Galden) is a suitable fluid that can be advantageously used as a pressure homogenizing fluid in both liquid and gaseous states.If the fluid source is provided in addition to the cylinder / piston arrangement described above, the supply of fluid into the pressure cushion can cause a further increase in pressure, even if further movement of the piston into the cylinder is no longer possible or desirable, for example because a mechanical limitation of the displacement path has become effective.

[0033] PFPE can preferably be used as a fluid in both liquid and, depending on the temperature range, gaseous form, and can be used for both heat transfer and pressure equalization. PFPE is a group of plastics that are typically liquid to pasty at room temperature. In particular, a perfluoropolyether with a boiling point of, for example, 260°C, also known as Galden HS260 (HS260 = 260°C boiling point), is used in vapor phase soldering. A key advantage over thermal oils is that if a membrane in the pressure pad ruptures or leaks, the escaping fluid is harmless to the components. Furthermore, the fluid can be vaporized under vacuum in a vacuum chamber and pumped out of the chamber using a vacuum pump.

[0034] According to a further advantageous embodiment, the guide frame comprises a punch guide plate which has guide channels for the axial guidance of the punch(es). The guide channels preferably extend in the direction of the pressing force at least through the punch guide plate and ensure lateral guidance of the punch(es), thus enabling precise positioning of the punch(es) relative to the components of the assembly. The punch guide plate can be designed as a single piece or as a two- or multi-piece piece.

[0035] According to a further advantageous embodiment, at least one flexible membrane is arranged between the pressure pad and the stamp(s). Here, the membrane serves as a kind of additional mechanical protective layer and, in particular, prevents the pressure pad from being unintentionally damaged by local pressure peaks when the stamp(s) are actuated.

[0036] In this context, it has proven advantageous for the membrane to cover the guide channels. This prevents the pressure pad from being forced into gaps that may exist between the punch(es) and the walls of the guide channels. This ensures that the pressure increase in the pressure pad is fully available to generate the pressing forces acting on the cross-sections of the press punches and does not lead to local bulging of the pressure pad into any gaps or spaces.

[0037] According to a further advantageous embodiment, the guide frame has a membrane retaining plate which is arranged on a side of the punch guide plate facing the pressure pad, wherein the membrane is held between the membrane retaining plate and the punch guide plate. The membrane retaining plate thus fixes the membrane to the punch guide plate and, in particular, also provides additional pretensioning of the membrane.

[0038] In this context, it has proven advantageous if the membrane retaining plate has at least one opening that extends at least across the guide channels. The opening can be designed as a large central opening that covers the punch guide plate only in its circumferential area and fixes the membrane between the membrane retaining plate and the punch guide plate. Preferably, however, the membrane retaining plate has several separate openings, each opening being assigned to a single or, preferably, a group of guide channels. In particular, the size and arrangement of the openings can correspond to the size and arrangement of an associated substrate to which electronic components are to be connected by the diffusion soldering or pressure sintering process. The guide channels are therefore not covered by solid sections of the membrane retaining plate, so that the...the stamps can come into contact with the pressure pad via the membrane.

[0039] According to a further advantageous embodiment, the punch(es) are permanently or detachably connected to the membrane, preferably by bonding. The connection between the punch(es) and the membrane ensures that the punch(es) cannot fall downwards out of the guide frame when the diffusion brazing and / or sintering device is in a rest position in which the upper tool is spaced apart from the lower tool.

[0040] According to a further advantageous embodiment, the upper tool has at least one locking device for the punch(es) which secures the punch(es) against falling out of the guide channels.

[0041] In this context, it has proven advantageous if the membrane is magnetic and the locking device comprises magnetic elements connected to the punch(es), preferably integrated into the punch(es), which hold the punch(es) to the membrane. This allows the magnetic elements to be held detachably or releasably on the membrane. This has the advantage that both the punch(es) and the membrane are reusable when the diffusion soldering and / or sintering device needs to be adapted to other assemblies that have components with different dimensions, particularly different heights, compared to the previously processed assemblies. Compared to permanently bonded punches, this offers the particular advantage that, if necessary, only a portion of the punches needs to be replaced. This reduces setup times and costs. The magnetic membrane can be part of the locking device.The magnetic elements also enable easy reconfiguration of the punch(es) via a quick-change system, allowing them to be adapted to changing assembly configurations. A single or multiple assembly is typically arranged in a workpiece carrier, which is guided through the diffusion brazing and / or sintering device during the machining process. Changing the assembly types or their arrangement within the workpiece carrier necessitates reconfiguration of the punch arrangement. This is significantly simplified and cost-effectively achieved with a quick-change system, particularly when using magnetic elements.

[0042] According to an alternative embodiment, the locking device comprises locking pins which are mounted in the punch guide plate and extend through recesses provided in the punches. This embodiment also allows for the replacement of the punch(es). The locking pins preferably have sufficient clearance in the recesses to ensure the necessary axial displacement of the punches for the diffusion brazing and / or sintering process. For this purpose, the recesses can, for example, be designed as elongated holes. The locking pins preferably extend with their longitudinal axis within a plane defined by the main extension direction of the punch guide plate. Corresponding bearing recesses or grooves for the locking pins can be formed in the punch guide plate, for example, in the form of milled depressions.In order to be able to mount and / or replace the punches or the locking pins, the punch guide plate can be designed in two parts with an upper and a lower punch guide plate.

[0043] According to a further advantageous embodiment of the invention, the punch(es) are received in the guide channels with lateral play. Should the contact surfaces between the components to be sintered and the punch(es) not be exactly parallel due to manufacturing tolerances, the lateral play of the punch(es) in the guide channels allows for a slight tilting of the punch(es) to achieve parallelism between the contact surfaces. This prevents uneven pressure application to the components and reduces the risk of pressure peaks. The play can range from approximately 1 µm to 1 mm and can, in particular, be configured as a parallel gap between the punch and the guide channel.

[0044] The punch(es) typically have a round cross-sectional shape. In another embodiment, the punch(es) can have an elliptical, square, or rectangular cross-section. Preferably, the guide surfaces, i.e., the corner regions of the punch's cross-section, are rounded to prevent local pressure peaks. The punch is bounded by an upper surface facing the pressure pad, a lower surface facing the pressing side and the component to be pressed, and an axial outer shell that is guided in the guide frame. The side surfaces of the outer shell are referred to as guide surfaces and are guided in the guide channel. The edge transitions of the guide surfaces are advantageously rounded to ensure jam-free guidance.A rectangular or square shape, particularly on the underside of the punch, but also on the entire punch cross-section, allows the punch cross-section to be adapted to the typical shape of components to be sintered, especially high-performance semiconductor components with rectangular or square package shapes. This enables a multi-punch unit with a number of adjacent, mutually sealing punches guided together, without any gaps between the punches. Thus, the multi-punch unit forms a closed sealing surface against the pressure pad without the need for limiting walls in the guide frame. The multi-punch unit can be sealed from the pressure pad by a metal foil, and it is also advantageous to magnetically connect the individual punches of the multi-punch unit to the metal foil.

[0045] With regard to the aforementioned embodiment, the guide frame, in particular the punch guide plate, can advantageously have a square or rectangular shape, and the guide channels can have a square or rectangular cross-sectional shape. This achieves a seal of the pressure pad by the guide frame and the punches guided in sealed guide channels, even without the use of an additional sealing membrane. A rectangular or square shape allows for better utilization of the surface area with respect to the pressing force, and also enables the processing of multiple components with the same force per unit area compared to round punches.

[0046] In an advantageous embodiment, one or more guide channels can accommodate a plurality of closely adjacent punches, which are preferably guided by themselves. This embodiment proposes a multi-punch unit as a punch assembly, wherein the guide frame has one or more guide channels, and several punches are guided in a guide channel. The punches are axially guided in the guide channel in a self-sealing manner and have contour shapes that enable a planar seal through the multi-punch surface over the guide channel cross-section. Thus, the punches can have concentric shapes relative to each other, or be guided adjacent to one another in a rectangular or square configuration. Other complex cross-sectional shapes that fill the guide channel are also conceivable.It is advantageous for the punches to have the same or different lengths relative to each other in order to be able to press components with a constant or varying height profile.

[0047] In a further advantageous embodiment, the punch(es) can have a sliding guide insert made of a softer material than the punch material, preferably plastic, on an upper guide side section facing the pressure pad. Preferably, a circumferential punch groove can be provided on the upper punch surface between the upper edge of the sliding guide insert and the upper punch surface. The sliding guide insert can provide an efficient seal between the upper area of ​​the punch, facing the pressure pad, and the guide frame or adjacent punches, and can be replaced cost-effectively when worn. The sliding guide insert can also secure the punch(es) in the guide channels of the guide plate by means of a force-fit or form-fit connection.For efficient sealing, a circumferential die groove, particularly one with sharp edges, at the upper end of the sliding guide insert opposite the surface of the die head has proven effective, allowing the pressure pad to act within this groove. If the sliding guide insert is made of a softer material than the die material, typically plastic versus metal, the die material generally has a higher coefficient of thermal expansion and therefore seals better at higher temperatures. Additionally, the softer material can ensure parallel alignment of the die with the surface of the component or assembly. Through the circumferential die groove, the pressure pad material, e.g., silicone, flows into the groove and presses the sliding guide insert against the outer wall of the guide channel.If the surface of the sliding guide insert facing the punch guide has a low-friction surface contour, such as a profiled shaft surface, the axial punch movement is sealed with reduced resistance, and the sliding guide insert remains in place on the guide side of the punch. The sliding guide insert can preferably be manufactured using 3D printing technology and, in particular, printed or injection-molded directly next to the punch groove onto an upper circumferential section of the punch guide side. A high coefficient of thermal expansion of the sliding guide insert material ensures a reliable seal in the guide channels of the guide plate. The use of the sliding guide insert achieves such a high sealing effect against the pressure pad that a membrane as a sealing element is unnecessary.A multi-stamp unit as described above can be advantageously used as the stamp, with a metal foil at the upper end of the sliding guide insert forming a seal against the pressure pad above it. Furthermore, the individual stamps of the multi-stamp unit can be magnetically attached to the metal foil in a force-fit manner.

[0048] In a further advantageous embodiment, the punch(es) can have a smaller or larger cross-section on the underside of the punch than on the top side. Different surface cross-sections of the top and bottom of the punch allow for pressure increases or decreases and enable efficient sealing of the pressure pad. Areas of the components to be sintered can be pressed with increased or reduced pressure, and the cross-sectional contour of the underside of the punch can also be adapted to specific requirements of the component geometry.

[0049] In a further advantageous embodiment, the piston can be guided in a sealed manner relative to the cylinder and thus be displaceable. The piston serves to increase the pressure in the pressure cushion, which in turn presses the punches from the upper tool towards the lower tool. As the upper and lower tools move together, a pressing force is exerted on the piston, which is movable within the cylinder and supported on the lower tool, particularly the assembly or a workpiece carrier. This pressing force is then transmitted to the pressure cushion. For sealing purposes, the punch(es) in the guide plate can be sealed against the pressure cushion, for example, by a large diaphragm, particularly a metal diaphragm. Alternatively, each punch can be sealed individually or as a group against the pressure cushion in the guide plate, for example, by diaphragm sections or by additional sealing elements on the punches.The punch can be formed by an underside of the pressure pad, in particular a silicone pad, which presses the assembly directly or with the interposition of a process cover such as a sintered film or the like. The sintered film can facilitate parallel alignment of the punch of the upper tool with the surface of the component or assembly on the lower tool. Furthermore, a sintered film prevents the silicone material from adhering to the component surface. Preferably, the piston is designed as a ring piston and more preferably comprises a piston jacket made of a harder material, in particular steel, and a piston sealing insert made of a softer material, in particular plastic, which is positively engaged in the piston jacket.The piston seal insert, made of a softer material, can, through heating and pressurization, seal the pressure cushion in the opening of the pressure chamber in such a way that it cannot be forced out through the gap between the piston and cylinder of the pressure unit. The material of the piston seal insert can be selected to match the pressure, temperature, and material of the pressure cushion, ensuring a seal of the pressure cushion in the cylinder under pressure. Furthermore, due to its compliant, soft properties, the piston seal insert facilitates the parallel alignment of the punch surface on the component surface and serves to align the punch surface of the upper tool with the component surface of the lower tool. The cylinder cross-section is preferably circular to provide a uniform pressure distribution.By using the piston seal insert, elliptical, square, rectangular, polygonal, or other cylinder cross-sectional shapes are also conceivable. These shapes, adapted to the assemblies being machined, enable a compact, space-saving arrangement of assemblies on workpiece carriers and high production throughput even at high temperatures and pressures. Cross-sectional shapes, especially square or rectangular shapes with rounded edges, are preferred to ensure a permanently tight seal between the piston and cylinder against the pressure cushion. The annular piston can have some clearance from the cylinder wall to allow it to slide within the cylinder. The aforementioned seal prevents the pressure cushion material from penetrating the gap between the annular piston and cylinder, even without an intermediate diaphragm.Inside the annular piston, the pressure cushion can be positioned gap-free against the inner wall of the piston seal insert. In this embodiment, the piston is guided gap-free in the guide channel formed by the inner wall of the annular piston.

[0050] In a further advantageous embodiment, the piston jacket can have a sealing seat on its upper surface facing the upper tool, in which a flanged area of ​​the piston sealing insert engages such that a circumferential sealing groove can be formed. Preferably, a pressure cushion on its upper surface can have a circumferential sealing rim which, when pressure is applied to the piston, can be forced into the piston's sealing groove, forming a sealing seam. The engagement of a flanged area of ​​the piston sealing insert with a sealing seat in the piston jacket enables, firstly, a positive-locking connection of the piston sealing insert and, secondly, the formation of a sealing groove that provides space for the pressure cushion to be displaced. This sealing groove thus provides a self-sealing effect of the pressure cushion against the gap between the piston and cylinder.The piston seal insert can be easily replaced in case of wear or conversion.

[0051] In a further advantageous embodiment, the piston and the pressure pad can be assigned to a punch, in particular the punch can be designed as a soft punch and can preferably be provided by the pressure pad, or the piston and the pressure pad can be assigned to a plurality of punches. In this embodiment, it is proposed that one or more pressure units can be arranged in the upper tool, each pressure unit comprising an individual punch. If the pressure unit essentially consists of the cylinder with integrated pressure pads, annular piston, and a guide frame, each pressure unit can form an individual punch. The underside of the pressure pad can, for example, serve as a soft punch, e.g., a silicone punch, but can also be designed as a hard punch with a hard stamping surface.Alternatively, a single, large pressure unit can be arranged in the upper tool, with a plurality of small punches arranged in the guide frame.

[0052] In a subordinate aspect, a press tool, designed as an upper or lower tool of the aforementioned diffusion soldering and / or sintering device, is proposed. This comprises a rigid base plate and either at least one membrane connected to the base plate, which is formed by a flexible membrane, preferably cup-shaped and preferably made of silicone or a steel alloy, or a plurality of membrane sections extending towards the pressing surface, or a guide frame with movably guided, sealed punches therein, and a pressure chamber, which preferably includes a pressure cushion filled with a fluid, arranged in a closed receiving space, which is bounded by the base plate and the membrane or the guide frame with sealing punches, wherein the guide frame closes off the pressure cushion (in the direction of the pressing surface) and guides the punches.The membrane and / or the piston seals seal the pressure chamber or the pressure cushion, preferably made of silicone, against the pressing surface and enable the arrangement of the pistons on the membrane surface or the guide frame, whereby, for example, magnetic attachment is facilitated in the case of metallic membranes, but other connection techniques such as screw connection, welding connection, rivet connection or similar are also conceivable.

[0053] In an advantageous embodiment, a section of the pressure chamber of the press tool described above, in particular at least a section of a pressure cushion housed in the pressure chamber, can be designed to be controllably filled with fluid, and especially with gas. Preferably, the fluid filling can be controlled by means of at least one filling valve. By filling a section of the pressure chamber with fluid, and in particular with gas, a pressing force can be generated by filling the pressure chamber with fluid, in addition to or as an alternative to the pressing force applied mechanically by the press. For example, by introducing atmospheric gas from the process chamber, or optionally purge gas such as nitrogen, into a section of the pressure chamber when the pressure is reduced or the process chamber is vacuumed, the pressure chamber can expand through the membrane or by displacing the sealed press rams.This generates a comparatively low, yet in many cases sufficient, pressure on the components for processes such as bonding, low-pressure sintering with silver or copper, diffusion soldering (up to 0.4 MPa), thermocompression bonding (up to 0.1 MPa), etc., without the need for a hydraulic press to mechanically drive the press rams. Thus, simply by setting a defined process atmosphere in the process chamber and / or the pressure chamber, a precisely metered pressing force can be applied to the component, which would not be achievable with a mechanical press by moving the lower and upper tools relative to each other.

[0054] The aforementioned embodiment allows for the cost-effective and simple provision of a press tool for additional or alternative pressure application to the press drive with minimal effort. This is because the desired and controlled sintering, diffusion soldering, or bonding pressure can be applied to components via the gas pressure and the process atmosphere or vacuum in the process chamber, which is essential for the process. This allows for the compensation of height differences between components on the component.

[0055] No additional force or pressure measuring system is necessary, as a vacuum pressure sensor and a simple software surface conversion are sufficient to achieve a desired and set sintering pressure, diffusion soldering pressure, or bonding pressure.

[0056] Since the vacuum chamber exerts pressure on the component(s) via the press tool, it is possible to continuously monitor whether oxygen is entering the chamber from the outside during the process, as an unexpected increase in chamber pressure can be detected immediately. This ensures that the hot component does not oxidize, especially copper surfaces. Pressure monitoring of the components can be performed using a load cell, which is integrated, for example, into the press drive. This allows, for instance, the detection of a punch jamming.

[0057] In a further, subordinate aspect, a diffusion soldering system and / or sintering system is proposed, comprising the aforementioned diffusion soldering device and / or sintering device and / or the aforementioned press tool. It is proposed that the diffusion soldering device and / or sintering device and / or the press tool be arranged in an atmosphere-tight module of a multi-module system, in particular in a vacuum module, wherein at least one further module is provided as a preheating and / or cooling module. Furthermore, a transport device is provided, which is configured to automatically move at least one workpiece carrier, in particular the lower tool, with at least one assembly through the multi-module system. Adjacent modules of the multi-module system are also to be sealed atmospherically from one another.

[0058] In other words, a multi-module system is proposed, comprising at least one atmosphere-tight module, in particular a vacuum module, which includes the aforementioned sintering or diffusion soldering device and / or the aforementioned press tool. Within this sintering / diffusion soldering module, the sintering and / or diffusion soldering process can be carried out under specifically adjustable atmospheric conditions, in particular under vacuum to eliminate oxidation processes. At least one further module can be configured as a preheating module and / or as a cooling module to reduce process times, as well as for special pre- and / or post-treatment, e.g., for cleaning, in particular with a process gas such as plasma, formic acid, nitrogen, etc., and temperature control. A workpiece carrier, which carries at least one, in particular several, assemblies or components, can be guided through the modules by a transport device, e.g., a conveyor belt system.Nevertheless, the entire lower tooling can be transported through the multi-module system using the transport device. The transition between modules can be sealed airtight, for example, by means of a gas lock, so that the atmosphere, pressure, and temperature can be set separately in each module. The multi-module system can be designed for batch operation in flow production and configured as a continuous flow system, whereby the transport device either moves the assemblies through the multi-module system or moves them in and out again. ZEICHNUNGEN

[0059] Further advantages become apparent from the accompanying drawing description. The drawings illustrate exemplary embodiments of the invention. The drawing, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations. Exemplary embodiments shown for a sintering device can nevertheless be implemented for diffusion soldering devices.

[0060] They show: Figs. 1 und 2 Schematic sectional views of a sintering device according to an exemplary embodiment in various working positions, Fig. 3 a perspective view of the sintering device of Fig. 1 und 2 in a resting position, Fig. 4 a perspective view in partial sectional representation of the sintering device of Fig. 1 bis 3 , Fig. 5 a side view of the sintering device of Fig. 1 bis 4 , Fig. 6 a perspective view of a guide frame of the sintering device of Fig. 1 bis 5 , Fig. 7 a perspective exploded view of the guide frame of Fig. 6 , Fig. 8 a perspective view of a component of the guide frame of Fig. 7 , Figs. 9 und 10 Partial views of the guide frame of Fig. 6 and 7 from different perspectives, Fig. 11 a perspective partial view in sectional view of the guide frame of Fig. 6 and 7 according to a design, Fig. 12 a perspective view of a management framework according to a further development, and Fig. 13 a perspective partial view in sectional view of the guide frame of Fig. 12 ; Fig. 14 an exploded view of a press tool of a sintering device according to an embodiment of the invention; Figs. 15a, 15b a sectional view through variants of the embodiment according Fig. 14 ; Fig. 16 a schematic side view of a sintering device of a further embodiment; Figs. 17a-17c a further pressing tool in several process stages of a sintering device according to an exemplary embodiment; Figs. 18a, 18b Sectional views of sealed press dies according to embodiments of the invention; Fig. 19 an embodiment of a pressing tool with a Fig. 18a depicted sealed press die; Fig. 20 In perspective, a multi-stamp unit of an embodiment with mutually adjacent and mutually sealed, movable stamps; Figs. 21a, 21b Top view and sectional view of a square ring piston with silicone pressure pads of an embodiment of the invention.

[0061] In the following description of exemplary embodiments and configurations, identical or similar elements are designated with the same reference numerals.

[0062] Fig. 1 und 2 Figure 10 shows an exemplary sintering device for joining components of a plurality of electronic assemblies 12 by means of pressure sintering. However, it is also possible to sinter only a single assembly 12. For the sake of clarity, in Fig. 1 und 2 Each shows only a single assembly 12, which comprises a substrate 12A and several electronic components 12B of different sizes.

[0063] The sintering device 10 comprises an upper tool 14 and a lower tool 16, which are adjustable relative to each other along a pressing direction R represented by a double arrow R. For the sake of clarity, further components of the sintering device 10, such as adjustment devices or holding devices for the tools 14 and 16, are not shown.

[0064] The upper tool 14 and the lower tool 16 can be heated, although for the sake of simplicity only a heating device 16 provided on the lower tool 16 is shown here.

[0065] The assemblies 12 to be sintered can, according to one embodiment, be held in a workpiece carrier 18, which preferably can be automatically inserted into the sintering device 10 by means of appropriate transport devices for simplified workpiece change, placed on the lower tool 16 and removed from the sintering device 10 after sintering has taken place.

[0066] The upper tool 14 includes a pressure unit 20, which defines a receiving chamber or receptacle 22 for a pressure pad 24 that completely fills the receptacle 22. The pressure pad 24 defines a volume that is surrounded by a fluid-tight flexible shell or pad membrane and filled with a fluid, for example, an elastomer such as silicone or grease, or a gas. The shell can be made, for example, of a coated glass fiber or aramid fiber fabric (Kevlar). The coating can be made, for example, using polytetrafluoroethylene (PTFE).

[0067] The pressure unit 20 comprises a cylinder 28 in which a piston 30 is displaceably guided along the pressing direction R. The receptacle 22 has an opening 26 on its underside facing the lower tool 16. In this embodiment, the opening 26 extends within the piston 30, so that the piston 30 forms a type of cylindrical ring piston. The receptacle 22 is bounded in the region of the opening 26 by a guide frame 40, which has several guide channels 42 in which one or more punches 60 are displaceably guided axially along the direction of the pressing force, i.e., in the pressing direction R. The punches 60 are preferably made of a highly thermally conductive, resistant material, for example, steel or another metal or metal alloy.The guide frame 40 is attached to the piston 30 by means of suitable connecting elements, for example locking or clamping elements, or screwed to the piston 30, so that the guide frame 40 can be replaced.

[0068] A flexible membrane 50 is arranged between the receptacle 22 and the pressure pad 24, covering the guide channels 42. In the Fig. 1 und 2 In the illustrated embodiment, the membrane is shown as a continuous membrane 50, wherein, according to a modification described in more detail below, the membrane can also be divided into several separate membrane sections 50A ( Fig. 5 and 7 ) may be subdivided. The membrane 50 or the membrane sections 50A may, for example, also be made of a coated glass fiber or aramid fiber fabric (Kevlar) and may be coated using polytetrafluoroethylene (PTFE) or other material.

[0069] The following explains the operation of the sintering device 10. As in Fig. 1 As shown, after the assemblies 12 or the workpiece carrier 18 have been placed on the lower tool 16, the upper tool 14 and the lower tool 16 are first brought closer together, which can be done either by moving the upper tool 14 or the lower tool 16. In the Fig. 1 In the situation shown, the upper tool 14 with the guide frame 40 is just being placed on the lower tool 16, or more precisely on the workpiece carrier 18 which is mounted on the lower tool 16.

[0070] Once the guide frame 40 has been placed on the workpiece carrier 18, the volume of the receptacle 22 is reduced as the upper and lower tools 14, 16 move closer together, since the piston 30 is moved into the cylinder 28. This creates pressure in the pressure pad 24, which moves or displaces the punches 60 out of the guide channels 42 towards the assemblies 12. The cover of the pressure pad 24 and the diaphragm 50 largely conform to the contours of the guide frame 40 and the top surface of the punches 60, respectively.

[0071] As soon as the punches 60 come into contact with the components 12B, a certain pressure builds up, which is initially very low until all components 12B are contacted by their respective punches 60. The pressure pad 24 provides hydraulic compensation, so that a greater pressure increase within the pressure pad 24 only occurs when all punches 60 are in contact with their respective components 12B. This results in a simultaneous and uniform build-up of the pressing force or pressure, ensuring that the pressure sintering of the assemblies 12 is very uniform. The sintering device 10 can be equipped with corresponding sensors to determine the pressing pressure. Heat transfer from a heating device (not shown) provided in the upper tool 14 to the assemblies 12 can occur via several paths: the cylinder 28, the piston 30, the pressure pad 24, the punches 60, the guide frame 40, and the diaphragm 50.A control device (not shown) can control or regulate process parameters such as pressing pressure, pressing time and / or pressing temperature according to a predefined process specification.

[0072] After completion of the sintering process, the upper tool 14 and the lower tool 16 are separated from each other, so that the workpiece carrier 18 with the assemblies 12 is released and can be removed from the sintering device 10.

[0073] With reference to now Fig. 3 bis 13 Various components of the sintering device 10 are described in more detail according to the exemplary embodiment and variations thereof.

[0074] In Fig. 3 The upper tool 14 with the pressure unit 20 and the attached guide frame 40 is shown. The workpiece carrier 18, which holds several electronic assemblies 12 to be sintered in corresponding compartments, is placed on the lower tool 16. To protect the assemblies 12 against dirt or contamination, a film (in Fig. 3 (not visible) arranged, which can be secured against unintentional slippage by a film retaining ring 32. To in turn secure the film retaining ring 32 against slippage, the workpiece carrier 18 can have a corresponding recess or groove 34. The film can improve parallel alignment between the upper tool 14 and the lower tool 16 and compensate for height differences.

[0075] The diameter of the film retaining ring 32 can be selected such that the guide frame 40 rests on the workpiece carrier 18 within the film retaining ring 32 and thus does not come into contact with the film retaining ring 32. Alternatively, the diameter of the film retaining ring can also be selected to be smaller, so that the guide frame 40 rests on the film retaining ring 32, thereby generating the pressing pressure in the pressure unit 20.

[0076] In Fig. 4 is the arrangement of Fig. 3 shown in a side view, showing only the workpiece carrier 18, but not the lower tool 16. Fig. 4 It is already apparent that the guide frame 40 is made up of several plates, which will be explained in more detail below.

[0077] With reference to Fig. 5 The construction of the upper tool 14, including the pressure unit 20 and the guide frame 40, is explained in more detail. The construction of the pressure unit 20 corresponds to the illustration of Fig. 1 und 2 In Fig. 5 and also in Fig. 6 The multi-part structure of the guide frame 40 is illustrated. The guide frame 40 comprises a two-part punch guide plate 46 with an upper punch guide plate 46A and a lower punch guide plate 46B. The guide channels 42 extend through both punch guide plates 46A and 46B. The punches 60 are guided in the guide channels 42 with a certain amount of lateral play, allowing them to tilt within the guide channels 42 to a certain extent. For example, the guide channels 42 and the punches 60 can have a square cross-section, with the side length being 8.00 mm for the guide channels 42 and 7.96 mm for the punches 60. These dimensions are purely exemplary and in no way limiting.

[0078] The piston 30 can be sealed against the cylinder 28 by a sliding guide insert 166, as shown in the Figs. 18a, 18b This is explained in detail. Alternatively, a sealing principle with a piston seal insert, as described in relation to the Figs. 21a, 21b as shown, to be used.

[0079] This moderate clearance ensures that the surfaces of the punches 60 and the assemblies 12 that come into contact can align themselves parallel to each other, if necessary, in order to avoid gradient formation when applying the pressing force and to further improve the homogeneity of the pressing.

[0080] As particularly in Fig. 6 As can be clearly seen, a membrane retaining plate 44 is arranged above the punch guide plate 46, which has several openings 48 that correspond to the respective compartments 36 formed in the workpiece carrier 18 for receiving the assemblies 12. Each opening 48 can span several guide channels 42 and the respective punches 60 arranged therein.

[0081] Each opening 48 is assigned a respective membrane section 50A, which is preferably slightly larger than the assigned opening 48, so that the membrane sections 50A can be clamped and held in position between the punch guide plate 46 and the membrane retaining plate 44.

[0082] The membrane retaining plate 44, the upper punch guide plate 46A and the lower punch guide plate 46B can be screwed together.

[0083] As in Fig. 7 As can be seen, corresponding recesses 54 can be formed on the upper surface of the upper punch guide plate 46A, the size of which is matched to the associated membrane sections 50A. According to one embodiment, the depth of the recesses 54 can be adapted to the thickness of the membrane sections 50A such that the membrane sections 50A protrude slightly upwards from the recesses 54 and can thus be clamped by means of the membrane retaining plate 54.

[0084] According to a Fig. 9 und 10 In the illustrated embodiment, the membrane retaining plate 44 can have a respective circumferential sealing edge 56 for each opening 48, which extends at a distance from the edge of the opening 48 and is designed as a kind of bead that clamps the associated membrane section 50A circumferentially. The sealing edge 56 can either consist of a flexible material that is embedded in the membrane retaining plate 44 or be formed by a corresponding projection provided on the membrane retaining plate 44.

[0085] To prevent the punches 60 from falling out of the guide channels when the upper tool 14 is raised, the sintering device 10 can have a locking device for the punches 60.

[0086] According to one embodiment of such a safety device, the membrane 50 or the membrane sections 50A can be magnetic, which can be achieved, for example, by coating the membrane 50 or the membrane sections 50A with a ferromagnetic or paramagnetic material. Alternatively, the magnetic material can also be embedded in the membrane 50 or in the membrane sections 50A in the form of micro- or nanoparticles.

[0087] Each punch 60 has a magnetic element 62 preferably flush-mounted in one of its end faces facing the membrane 50. These magnetic elements 62, made of a temperature-resistant, permanent magnetic material, interact with the magnetic membrane 50 and thus prevent the punches 60 from falling out of the guide channels 42. For any necessary replacement of the punches 60, they can be released from the membrane 50 by applying a force sufficient to overcome the holding force. In this configuration, the punch guide plate 46 can also be formed as a single piece.

[0088] With reference to now Fig. 12 und 13 A further embodiment of the guide frame 40 is described, which features an alternative locking device for the punches 60. The punches 60 are provided with elongated recesses 64 through which elongated locking pins 66 extend. The locking pins 66 are held in short grooves 52 formed on the upper side of the lower punch guide plate 46B. To ensure secure retention of the locking pins 66, corresponding grooves (not shown) can also be provided on the underside of the upper punch guide plate 46A. The locking pins 66 can be clamped between the upper punch guide plate 46A and the lower punch guide plate 46B.

[0089] The recesses 64 in the punches 60 are dimensioned such that the axial displacement of the punches 60 necessary for the sintering process is provided. The locking pins 66 can have a round or rectangular cross-section. A single locking pin 66 can also extend through several punches 60 if this is necessary due to space constraints.

[0090] According to another aspect of the invention, Fig. 14 und 15a or 15b a press tool 70 for an embodiment of a sintering device 10. The press tool 70 is shown without the guide frame 40 and punch 60, which would have to be added in the direction of the pressing surface 92. The press tool 70 can be configured as either an upper or a lower tool and comprises a base plate 72 and a cylindrical wall section 74 extending away from the base plate 72. The square shape of the base plate 72 and the cylindrical shape of the wall section 74 shown in the exemplary embodiment are purely illustrative and can each have different shapes.

[0091] A cavity defined by the base plate 72 and the wall section 74 is closed by a metallic membrane 50. The membrane 50 can be flat or cup-shaped, for example, manufactured by deep drawing from a metal membrane or a metal foil, with a steel alloy, for example a chromium-nickel steel alloy, being the preferred material for the membrane 50. Punches 60 can be arranged on the pressing surface 92 of the membrane 50, for example, by magnetic attachment. The membrane 50 encloses the cavity on its side facing away from the base plate 72, in which, for example, a pressure pad 90 can be accommodated. Alternatively, a support structure, for example a mechanically soft or liquid metal, a fluid chamber, or a silicone pad, can also be accommodated in the cavity.The membrane 50 can have a circumferential edge section that extends laterally to the wall section 74 and is clamped, for example, between the base plate 72 and a clamping ring 84. The clamping ring 84 can be screwed to the base plate 72, in particular attached to the open section of the wall section 74, and can secure the preferably cup-shaped edge section of the membrane 50. Alternatively, the membrane 50 can be attached directly to the wall section 74. A ring piston 76 can be inserted in a circumferential groove arranged in the clamping ring 84, which can interact with an inner circumferential surface of the wall section 74 as a cylinder and with the pressure pad 90 in the manner described above to build up pressure.

[0092] The cavity formed between the base plate 72 and the membrane 50 defines a fully enclosed receiving space for a pressure pad or pressure chamber 90. This receiving space can, for example, form a pressure chamber 90 filled with a fluid, such as silicone or oil, or contain a pressure pad 90, which can be, for example, an oil-filled pad, a silicone pad, or something similar. The pressure pad 90 can, for example, have threaded inserts that allow it to be screwed to the base plate 72.

[0093] The thickness of the membrane 50 is chosen such that, in the area of ​​a pressing surface 92, which interacts with the components of an electronic assembly to be joined via the punches 60 (not shown), the membrane 50 exhibits sufficient elasticity to deform to a suitable extent and to provide pressure equalization between adjacent components via the pressure pad 90. The membrane 50 can have a uniform thickness or areas of varying thickness. Thus, the membrane 50 can be thickened or thinned in certain areas, thereby exhibiting a structure corresponding to different pressure zones depending on the arrangement of the components 130 to be pressed or the arrangement of the punches 60. The size relationships in the illustration Fig. 14 und 15a, 15b are not necessarily to scale. In particular, the thickness of the membrane 50 may also be smaller than shown. Furthermore, a multitude of individual membranes 50a may each individually cover opening areas 48 of a guide frame 40, as shown in Fig. 5 is shown.

[0094] With reference to Fig. 16 A further embodiment of a sintering device 10 is described, wherein the features described in this context are combined with the features of the sintering device 10 described above according to Figs. 1 bis 15 can be implemented as well as being used in other, similar sintering devices.

[0095] The in Fig. 16 The sintering device 10, shown schematically and not to scale, comprises a press yoke 112, which receives the upper tool 120, and a press ram 114 located below the press yoke 112, which receives the lower tool 122. These components can be moved relative to each other in the direction R by means of a drive to apply a pressing force to the components 130 of an electronic assembly to be joined, which are arranged between the upper tool 120 of the press yoke 112 and the lower tool 122 of the press ram 114. The drive can act on both the press yoke 112 and the press ram 114 and can, for example, be designed as a hydraulic press with a press drive 34.An upper press tool 70, designated as upper tool 120, for example as a hard or soft tool, is arranged on the underside of the press yoke 112. A graphite foil 140 is provided between the press yoke 112 and the upper tool 120. This foil facilitates pressure and gradient compensation between the press yoke 112 and the upper tool 120, as well as supporting parallel alignment and height compensation. The graphite foil 140 can be adapted in type and thickness such that, acting like an elastic foil, it can achieve a predictable alignment between the upper hard tool 120 and a lower tool 122 when a pressing force is applied between the upper and lower tools. Thus, precise parallel alignment of the upper and lower tools can be achieved by means of the graphite foil 140.

[0096] The upper tool 120 can be a hard tool or a soft tool with an elastic sintered pad 24. A previously described upper tool 14 or the one described in the Figs. 15a, Fig. 15b The press tool shown, 70, or a combination thereof, is shown. Fig. 16 As an example, a press tool 70 with rotating ring pistons 126 for pressing a sintering pad 24 is shown as the upper tool 120, wherein the sintering pad 24 acts on individual punches 60, guided in openings 48 of a punch guide plate 46, via a membrane 50. The punches 60 are aligned with the components 130 to be sintered.

[0097] On the upper side of the press ram 114 is a heating plate 124, which may have one or more heating devices as well as one or more cooling devices. The lower tool 122 is arranged on the upper side of the heating plate 124 and has a receptacle on its surface for an elastic pressure pad 90. Alternatively or additionally, a pressure pad 24 in a soft tool configuration can be provided in the upper tool 120, so that the upper hard tool 120 and / or the lower tool 122 can be operated by a press tool 70, as shown in the Figs. 14, 15a oder 15b will be displayed, replaced.

[0098] The components or elements 130 to be joined are arranged on the pressure pad 90. A press tool 70 with a continuous metal membrane 50 and punches 60 guided in openings 48 of a guide frame are arranged in the upper tool and can exert a sintering pressure on the components 130. Optionally, one or more release films can be provided below and above the components 130 to prevent them from sticking to the pressure pad 90 or the punches 60.

[0099] The Figs. 17a bis 17c show an embodiment of a diffusion soldering and / or sintering device 10 with a single assembly 12 with a component 130 in combination with a press tool 70, as is found, for example, in the Fig. 8 The process chamber 160 comprises an upper tool 14 and a lower tool 16. The upper tool 14 is enclosed in a press yoke 120.

[0100] A press drive 34 is arranged in the lower tool 16. This drive, via a press ram 114, can exert a feed force on a component 130, which is mounted in a workpiece carrier (not shown), relative to the press tool 70 arranged in the upper tool 14. Several components 142, for example, power semiconductor components such as IGBTs or similar, are arranged on the component 130 of the assembly 12. The components 142 of the component 130 can have different heights and are to be connected on the component 130 in a diffusion soldering, bonding, or sintering process, for example, with a cooling structure and connecting leads. For this purpose, the component 130 can be covered with a process cover (not shown), such as a film or similar material, to prevent contamination and for protection. Fluid channels 156 for temperature control, i.e., for guiding a heating or cooling fluid such as oil or air, are integrated into the press yoke 120.

[0101] In the press tool 70, a heating plate 124 is arranged as a heating device 17, which may have fluid channels for heating and / or cooling. The heating plate 124 defines a pressure chamber 90 at its lower boundary, in which a pressure cushion may be inserted. The pressure chamber 90 has a chamber section 144 that can be filled with fluid in a controllable manner. The fluid can be a gas or a liquid. In this embodiment, it is provided that the chamber section 144 is filled with atmospheric gas from the process chamber 160, for example, with a cleaning gas such as nitrogen or with air. For this purpose, two filling valves 146 are provided in the press yoke 120, which, via valve actuators 148, enable a fluid-tight closing or opening of the chamber section 144 of the pressure chamber 90 relative to the process chamber 160.

[0102] The pressure chamber 90 is further delimited towards the lower tool by a metal diaphragm, designated as diaphragm 50. The metal diaphragm can, for example, be a steel diaphragm, such as a cup-shaped sheet of steel. By filling the chamber area 144 with fluid, the metal diaphragm can be forced downwards towards the process chamber 160.

[0103] A multi-punch unit 150 is arranged below the membrane 50. The multi-punch unit 150 comprises a guide plate 154, which accommodates and guides several press punches 152. The press punches 152 serve to selectively apply pressing force to predefined areas of the component 130 and can be adapted in shape and size to the various geometric dimensions of the components 142 into which the pressing force is to be applied. When pressure is applied, i.e., when the press drive 34 is activated, the press punches 152 are moved within the guide frame 154 towards the component 130 to selectively apply the pressing force.

[0104] In the Figs. 17a bis 17c In the depicted process, pressure is to be applied – independently of any pressing force generated by the press drive 34 – by means of a bulging of the membrane 50 due to a pressure difference between process chamber 160 and fluid-fillable chamber areas 144 of the pressure chamber 90. The magnitude of the pressure force is determined by the pressure difference between chamber area 144 and process chamber 160; this causes the membrane 50 to be displaced towards the lower tool 16 and thereby exerts pressure on the component 130.

[0105] In the first process step, as shown in Fig. 17a The fluid valves 146 are in an upper position, so that chamber area 144 is in fluid communication with process chamber 160. In the second process step, process chamber 160 is vacuumed, which also leads to the vacuuming of chamber area 144. The first and second process steps are in Fig. 17a depicted.

[0106] In the subsequent third process step, the process chamber 160 is flooded with a cleaning gas such as nitrogen, which penetrates the chamber area 144 of the fluid chamber 90. Then, in the fourth process step, the filling valves 146 are fluid-tightly separated from the process chamber 160 by means of the valve actuators 148. Following this, in the fifth process step, the press drive 34 is activated until a workpiece carrier (not shown) with the component 130 and a process cover (also not shown) is adjacent to the multi-punch unit 154. Steps three to five are described in Fig. 17b shown.

[0107] In the subsequent sixth process step, illustrated in Fig. 17c The process chamber 160 is evacuated. Due to the pressure difference between chamber area 144 of pressure chamber 90 and process chamber 160, the membrane 50 bulges downwards, displacing the press rams 152 within the guide frame 154 towards the component 130, so that selective pressure is applied to the individual components 142. Height differences of the components 142 can be compensated for, and the pressing force can be finely metered depending on the pressure difference.

[0108] This pressurization, resulting from the pressure difference between process chamber 160 and pressure chamber 90, can be applied alternatively or additionally to a pressing force exerted by the press drive 34. The pressures generated in this way are generally lower and more finely controllable than those achieved through mechanical pressure application by the press drive 34. This effectively supports bonding, diffusion brazing, or low-pressure sintering processes.

[0109] In the Figs 18a, 18b Two embodiments of sealed press dies 152 are shown. In the Fig. 18a A press ram 152, made of a hard material such as steel, is axially mounted and guided in a guide channel 42 of a guide frame 40. A pressure pad 24, e.g., made of silicone, and / or a pressurizable pressure chamber 90 are arranged above the guide frame 40. The pressure chamber 90 is sealed by the guide frame 40 and the press ram 152, which is sealed in the direction of the pressure pad 24 or the pressure chamber. The press ram 152 has a lower surface 170 facing a component 12B to be pressed and an upper surface 168 facing the pressure pad 24 or the pressure chamber 90. The cross-sectional shape of the press ram 152 is preferably square or rectangular and may have rounded corners, so that at least one lower surface 170 can be adapted to the size of a component 12B to be pressed.The axial circumference of the press ram 152 has a ram guide side 162 that abuts the inner surface of the guide channel 42, and this guide side has a ram guide side section 164 in the region of the ram's upper surface 168. The ram guide side section 164 can be radially recessed and, along its circumference, accommodate a sliding guide element 166 to fill the recess, acting as a sealing insert. The sliding guide element 166 is preferably made of a heat-resistant plastic, silicone, or some other material softer than that of the press ram 152, in particular a material with a higher coefficient of thermal expansion than the ram material. A suitable material is, for example, a high-temperature thermoplastic, especially a polyetheretherketone or polyimide, which is marketed under the brand names PEEK, Tecapeek, or Vespel.Furthermore, materials, particularly plastics, with high electrical and thermal conductivity, such as graphite, can be used. Preferably, the sliding guide element 166 is injection-molded along the punch guide side section 164 or printed directly onto it using a 3D printing process. At the transition between the upper surface of the sliding guide element 166 and the upper surface of the punch 168, a preferably circumferential punch groove 174 is formed in the upper surface of the punch 168, through which the pressure pad 24 penetrates and, upon thermal expansion due to heating of the press punch 152, displaces the upper surface of the sliding guide element 166 towards the cylinder wall of the guide channel 42, thus improving the seal.

[0110] In the exemplary embodiment of the Fig. 18a The area of ​​the bottom of the die (170) is smaller than the area of ​​the top of the die (168), so that the pressing pressure can be increased. In contrast, in the Fig. 18b An embodiment of a press punch 152 is shown, the underside of which 170 is enlarged compared to the top side 168 in order to reduce the pressing pressure or to be able to press an enlarged area of ​​a component 12B.

[0111] Also shown in an enlarged view in Fig. 18b A partial perspective cross-sectional view of the sliding guide insert 166 is shown. On the side facing the cylinder wall of the guide channel 42, the sliding guide element 166 has a friction-reducing surface contour 176, e.g. a groove contour, so that the friction during an axial movement of the press ram 152 is reduced against the outer wall of the guide channel 42.

[0112] The Fig. 19 shows another embodiment of a press tool 70, in which, by way of example, a tool as in Fig. 18a The press die shown is used. Typically, several such press dies are mounted in a common guide frame or in several guide frames within the press tool 70. The press tool comprises an upper tool 14 and a lower tool 16. A workpiece carrier 18 can be mounted in the lower tool 16. A substrate 12A and a component 12B can be arranged on the workpiece carrier 18 as the assembly 12 to be joined. Optionally, a process cover, e.g., a temperature-resistant film, can be temporarily positioned between the assembly 12 and the upper tool 14 during the sintering or pressing process (not shown).

[0113] The upper tool 18 comprises a guide frame 40, which includes one or more press rams 152 mounted in guide channels 42. The guide frame seals a pressure cushion 24 located above it against the assembly 12. The pressure cushion 24, or a pressure chamber 90, can be pressurized or depressurized via a filling valve 146. Two or more positioning elements 172, e.g., indexing rods, serve to position the upper tool 14 relative to the lower tool 14 and to fix a process cover. The positioning elements 172 can be extended and retracted via a traversing unit (not shown).

[0114] The lower tool 16 can include a transport frame for receiving a workpiece carrier 18, which can be automatically transported through the sintering device 10 on a transport unit (not shown). The workpiece carrier can be inserted into and removed from the lower tool 16. The transport frame can be made of an electrically conductive, pressure-resistant material such as stainless steel, and may, for example, have connecting strips made of a weight-reduced, also electrically conductive material such as an aluminum alloy.

[0115] In addition, Fig. 20 Figure 1 shows a perspective view of an embodiment of a multi-punch unit 150, as it can be used in a press tool 70. Typically, each press punch 152 is guided in a guide channel 42 of a guide frame 40. In this embodiment, several press punches are guided axially relative to one another and in a common guide channel 42. The press punches are axially displaceable relative to each other. Sealing against a pressure chamber 90 (not shown) or a pressure pad 24 can be achieved via a previously described membrane 50 or membrane sections 50A, or via sliding guide inserts 166, which are provided for each press punch 152. Advantageously, a metal membrane can be used, with the individual press punches 152 being magnetically attached to the metal membrane in a force-fit manner. With adapted lengths and sizes of the individual press punches 152, the multi-punch unit 150 enables pressing or...Sintering of assemblies 12 with closely adjacent structures of varying heights. A pressure-resistant mask can also be placed on a lower tool 16, allowing individual press punches 152 to penetrate while retaining other press punches 152. This enables flexible adaptation to different assemblies 12 by using a pressure mask on the lower tool 16 instead of modifying the guide frame 40 of the upper tool. This allows for flexible and cost-effective adaptation to varying pressing or sintering tasks, especially for small production runs. It is advantageous to use a multi-punch unit 150 instead of a single punch 152 in the [tool / machine / machine / machine]. Figs. 18a, 18b to use the depicted concept of a stamp seal. Instead of the one in the Figs. 18a, 18b The single punch 152 shown can thus be used in a plurality of small single punches 152, which are preferably sealed against the pressure pad 24 by a metal membrane on the upper side of the punch 168. The single punches 152 can adhere magnetically to the metal membrane. Thus, very small component sizes of a few millimeters, e.g., with an edge length of 5 mm or less, of a complex component 142 can be pressed onto a component 130 using small single punches 152 of a multi-punch unit 150, where individual sealing of the small single punches 152 would not be possible or only possible with difficulty.

[0116] Finally, they show Figs. 21a, 21b An embodiment of a square piston 30 as an annular piston 76 with a pressure pad 24 as a silicone pad of an embodiment. Due to the square shape of the piston surface, which forms the lower pressure pad side 180, space-saving piston shapes adapted to the usual shape of the assemblies, in particular power semiconductors such as IGBTs, can be provided. The lateral edges of the guide faces of the annular piston 76 are rounded to avoid stress concentrations in the area of ​​the cylinder wall and to ensure the sealing effect of the piston 30 in the cylinder 28. Fig. 21a Figure 1 shows a top view and a sectional view AA of a piston 30 as a rectangular ring piston 76 with rounded side edges or guide faces. The piston 30 comprises a piston jacket 184 made of a hard material such as steel and a piston seal insert 186 made of a soft material, preferably plastic, which is positively inserted therein. The soft material facilitates parallel alignment of the punch 60 with respect to the surface of the component 130 or the assembly on the lower tool 16. The sectional view AA shows a section through the piston 30 in the specified viewing direction of the top view, folded upwards. The piston 30 has a piston top 198 through which the Fig. 21b The illustrated soft cushion 24, which simultaneously forms a punch 60 as a soft punch, is penetrated and exits onto a piston underside 196 as the piston 30 is inserted into a cylinder 28 (not shown). This occurs because the piston 30 reduces the volume of the pressure cushion 24 by supporting itself on the assembly 12, a workpiece carrier 18, or the lower tool 16, while the upper tool 14 moves towards the lower tool 16. On the piston top side 198, the piston jacket 184 of the annular piston 76 has a sealing seat 200 in the form of a protruding circumferential edge. A sealing groove 188 is formed by the positive insertion of the piston sealing insert 186 from the piston top side 198. This groove is bounded on the piston sealing insert side 186 by a flange area 190 that fits into the sealing seat 200.A soft pressure pad 24 penetrates the sealing groove 188 when pressurized, preventing the pressure pad from entering a gap between piston 30 and cylinder 28. The circumferential upper edges around the top surface 198 of the annular piston 76, particularly along the sealing seat 200, are sharp to improve the sealing effect, while the circumferential lower edges on the underside 196 of the annular piston 76 are rounded to avoid stress concentrations on the component or assembly.

[0117] In the Fig. 21b Figure 1 shows a bottom view and a sectional view BB of a pressure pad 24, which in this embodiment is designed as a punch 60, a so-called soft punch. The sectional view BB is to be understood as a downward-folded representation along the section line BB of the top bottom view. The pressure pad 24 can be designed as a silicone punch and can have a recess in its interior for a hard punch insert, e.g., a metal block. The underside 180 of the pressure pad can form a punch pressing surface. A sealing rim 192 is formed on the top side 182 of the pressure pad. After an initial pressing operation, a sealing seam 194 is formed by the displacement of the material of the sealing rim 192 of the pressure pad 24 into the sealing groove 188 of the piston 30, which effectively seals the top side 182 of the pressure pad against the piston 30 and the cylinder 28 (not shown). BEZUGSZEICHENLISTE

[0118] 10 Sintering device 12 Assembly 12A Substrate 12B Component 14 Upper tool 16 Lower tool 17 Heating device 18 Workpiece carrier 20 Pressure unit 22 Mounting 24 Pressure pad 26 Opening 28 Cylinder 30 Piston 32 Film retaining ring 34 Press drive 40 Guide frame 42 Guide channel 44 Membrane retaining plate 46 Punch guide plate 46A Upper punch guide plate 46 Lower punch guide plate 48 Opening 50 Membrane 50A Membrane section 52 Groove 54 Recess 56 Sealing edge 60 Punch 62 Magnet element 64 Recess 66 Locking pin 70 Press tool 72 Base plate 74 Wall section 76 Ring piston 84 Clamping ring 90 Pressure pad 92 Pressing surface 112 Press yoke 114 Press punch 120 Upper tool 122 Lower tool 124 Heating plate 126 Ring piston 130 Component,Component 140 Elastic film / graphite foil 142 Component on component 144 Fillable chamber area of ​​the fluid chamber 146 Filling valve 148 Valve actuator 150 Multi-punch unit 152 Press punch 154 Guide frame 156 Fluid channels for temperature control 160 Process chamber 162 Punch guide side 164 Punch guide side section 166 Sliding guide insert 168 Punch top 170 Punch bottom 172 Positioning element 174 Circumferential punch groove 176 Friction-reducing surface contour 180 Pressure pad bottom 182 Pressure pad top 184 Piston sleeve 186 Piston sealing insert 188 Sealing groove 190 Sealing insert flange area 192 Pressure pad sealing edge 194 Pressure pad sealing seam 196 Piston bottom 198 Piston top 200 Piston jacket sealing seat , Pressing direction

Claims

1. Diffusion soldering device and / or sintering device (10) for connecting components of at least one electronic assembly (12) by means of diffusion soldering and / or pressure sintering, with an upper tool (14, 120) and a lower tool (16, 122) between which the at least one assembly (12) is held, wherein the upper tool (14, 120) has at least one pressure pad (24, 90) filled or fillable with a fluid or with a displaceable medium whose internal pressure is variable and at least one, in particular several, plungers (60, 152) in operative connection to the pressure pad (24, 90) and configured for transmission of a press force generated by a pressure increase in the pressure pad (24, 90) to the assembly (12), wherein the upper tool (14, 120) has a guide frame (40, 154) in which the plunger(s) (60, 152) is / are guided axially movably along the effective direction of the press force, whereby the plunger(s) (60, 152) are guided movably in the guide frame (40, 154) while sealed against the pressure pad (24, 90), whereby the upper tool (14, 120) has at least one pressure unit (20) with a receptacle (22) for the pressure pad (24, 90), characterized in that Diffusion soldering device and / or sintering device (10) according to claim 2 or 3, characterized in that the pressure unit (20) has a cylinder (28) and a piston (30) movably held therein, wherein the cylinder (28) and the piston (30) define the receptacle (22) for the pressure pad (24, 90) such that the volume of the receptacle (22) is variable by movement of the piston (30).

2. Diffusion soldering device and / or sintering device (10) according to claim 1, whereby the pressure unit (20) has an opening (26) facing the lower tool (16, 122) and covered by the guide frame (40, 154), the pressure pad (24, 90) resting on the guide frame (40, 154).

3. Diffusion soldering device and / or sintering device (10) according to claim 2, whereby the opening (26) is provided in the piston (30).

4. Diffusion soldering device and / or sintering device (10) according to claim 1 or 3, whereby the upper tool (14, 120) and the lower tool (16, 122) are movable relative to one another along the effective direction of the press force, wherein the piston (30) is moved into the cylinder (28) when the upper tool (14, 120) contacts the lower tool (16, 122) or a workpiece carrier resting on the lower tool (16, 122).

5. Diffusion soldering device and / or sintering device (10) according to any of the preceding claims, whereby the pressure pad (24, 90) is connected or connectable to a fluid source for supplying fluid into the pressure pad (24, 90), wherein the pressure increase can be effected by the supply of fluid.

6. Diffusion soldering device and / or sintering device (10) according to any of the preceding claims, whereby the guide frame (40, 154) comprises a plunger guide plate (46) having guide ducts (42) for axial guidance of the plunger(s) (60, 152).

7. Diffusion soldering device and / or sintering device (10) according to claim 6any of the preceding claims, cwhereby at least one flexible membrane (50, 50A) covering the guide ducts (42) is arranged between the pressure pad (24, 90) and the plunger(s) (60, 152).

8. Diffusion soldering device and / or sintering device (10) according to claim 7, whereby the guide frame (40, 154) has a membrane holding plate (44) which is arranged on a side of the plunger guide plate (46) facing the pressure pad (24, 90), wherein the membrane (50, 50A) is held between the membrane holding plate (44) and the plunger guide plate (46).

9. Diffusion soldering device and / or sintering device (10) according to claim 8, whereby the membrane holding plate (44) has at least one penetration (48) which extends at least over the guide ducts (42).

10. Diffusion soldering device and / or sintering device (10) according to any of claims 7 to 9, whereby the plunger(s) (60, 152) is / are permanently or detachably connected to the membrane (50, 50A), preferably bonded.

11. Diffusion soldering device and / or sintering device (10) according to any of claims 6 to 10, whereby the upper tool (14, 120) has at least one securing device for the plunger(s) (60, 152) which secures the plunger(s) (60, 152) against dropping out of the guide ducts (42).

12. Diffusion soldering device and / or sintering device (10) according to claims 10 and 11, whereby the membrane (50, 50A) is magnetic and that the securing device comprises respective magnetic elements (62) connected to the plunger(s) (60, 152), preferably integrated into the plunger(s) (60, 152), which hold the plunger(s) (60, 152) on the membrane (50, 50A).

13. Diffusion soldering device and / or sintering device (10) according to claim 11 or 12, whereby the securing device comprises respective securing pins (66) mounted in the membrane holding plate (44) and extending though recesses (64) provided in the plunger(s) (60, 152).

14. Diffusion soldering device and / or sintering device (10) according to any of claims 6 to 13, whereby the plunger(s) (60, 152) are held in the guide ducts (42) with lateral clearance.

15. Diffusion soldering device and / or sintering device (10) according to any of the above claims, whereby the plunger(s) (60, 152) can have a square or rectangular cross-section, wherein the guidance sides (162) of the plunger(s) (60, 152) are preferably rounded.

16. Diffusion soldering device and / or sintering device (10) according to claims 6 and 15, whereby the guide frame (40, 154), in particular the plunger guide plate (46), has a square or rectangular shape, and the guide ducts (42) have a square or rectangular cross-sectional shape.

17. Diffusion soldering device and / or sintering device (10) according to claim 6, whereby one or more guide ducts (42) holds a plurality of closely adjacent plunger(s) (60, 152) that are preferably guidable along each other.

18. Diffusion soldering device and / or sintering device (10) according to any of the above claims, whereby the plunger(s) (60, 152) have a sliding guide insert (166) made of a softer material, preferably plastic, than the plunger material on an upper guidance side section (164) facing the pressure pad (24, 90), wherein an all-round plunger groove (174) is provided preferably on the plunger upper side (168) between the upper edge of the sliding guide insert (166) and the plunger upper side (168).

19. Diffusion soldering device and / or sintering device (10) according to any of the above claims, whereby the plunger(s) (60, 152) on the plunger underside (170) have a smaller or larger cross-section than on the plunger upper side (168).

20. Diffusion soldering device and / or sintering device (10) according to any of the above claims 1 bis 4, whereby the piston (30) is guided movably while sealed against the cylinder (24, 90), wherein the piston (30) is preferably formed as an annular piston (76, 126) and preferably comprises a piston skirt (184) of a harder material, in particular steel, and a piston sealing insert (186) of a softer material, in particular plastic, positively held in the piston skirt (184).

21. Diffusion soldering device and / or sintering device (10) according to claim 20, whereby the piston skirt (184) has a sealing seat (200) on its piston upper side (198) facing the upper tool (14, 120), in which seat a flange area (190) of the piston sealing insert (186) engages such that an all-round sealing groove (188) is formed, wherein a pressure pad (24) preferably has on the upper side (182) an all-round sealing edge (192) which, when pressure is applied to the piston (30), can be forced into the sealing groove (188) of the piston (30) with a seal seam (194) being formed.

22. Diffusion soldering device and / or sintering device (10) according to claim 20 or 21, whereby the piston (30) and the pressure pad (24) are associated with a plunger (60, 152), in particular the plunger (60, 152) is designed as a soft plunger and can preferably be provided by the pressure pad (24), or the piston (30) and the pressure pad (24) are associated with a plurality of plungers (60, 152).

23. Press tool (70) designed as an upper tool (14, 120) or a lower tool (16, 122) of a diffusion soldering device and / or sintering device (10) according to any of the preceding claims, comprising a rigid baseplate (72) and either at least one membrane (50, 50A) connected to the baseplate (72) which is formed by a flexible, preferably dish-shaped membrane (50) preferably made from silicone or a steel alloy or a plurality of membrane sections (50A), in the direction of the press surface (92), or a guide frame (40, 154) with at least one, in particular several plungers (60, 152) movably guidable therein, and with a pressure chamber preferably comprising at least one pressure pad (24, 90) filled with a fluid and arranged in a closed receiving space limited by the baseplate (72) and the membrane (50, 50A) or the guide frame (40, 154) with at least one, in particular several sealing plungers (60, 152), wherein the guide frame (40, 154) closes the pressure pad(s) (24, 90) in the direction of the press surface (92) and guides the plunger(s) (60, 152).

24. Press tool (70) according to claim 23, whereby at least one sub-area of the pressure chamber, in particular a sub-area of the pressure pad (24, 90) is controllably fluid-fillable, in particular gas-fillable, and preferably by means of at least one filler valve (146).

25. Diffusion soldering facility and / or sintering facility comprising a diffusion soldering device and / or sintering device (10) according to any of the above claims 1 to 22 and / or a press tool (70) according to claim 23 or 24, whereby the diffusion soldering device and / or sintering device (10) and / or the press tool (70) are arranged in an atmospherically tight module of a multi-module system, in particular in a vacuum module, wherein at least one further module is provided as a preheating and / or cooling module, and wherein a transport device is provided which is configured to automatically move at least one workpiece carrier (18), in particular the lower tool (16), with at least one assembly (12) through the multi-module system, and wherein adjacent modules of the multi-module system are sealable atmospherically tight against one another.