Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/46—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids
  • H01L23/473—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements involving the transfer of heat by flowing fluids by flowing liquids
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/095—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00 with a principal constituent of the material being a combination of two or more materials provided in the groups H01L2924/013 - H01L2924/0715
  • H01L2924/097—Glass-ceramics, e.g. devitrified glass
  • H01L2924/09701—Low temperature co-fired ceramic [LTCC]

Definitions

• the invention relates to a micro heat exchanger for the transfer of high area-specific amounts of heat according to the first and the use of the same as a fluid cooler for an electronic component according to the seventh claim.
• heat loss-dependent quantities of heat often occur, which can be reliably dissipated using suitable coolants.
• the amount of heat is usually dissipated via heat-conducting solids and / or fluidic coolant flows, e.g. air, oil or water cooling.
• Known coolants for microelectronics usually include heat sinks which are directly connected to the electronic component to be cooled and which, via a cooling rib, pass on the amount of heat absorbed to an inflowing fluid, preferably air.
• the heat sinks capture the amount of heat to be dissipated due to their good thermal conductivity and a relatively large heat capacity and thus to a certain extent compensate for locally occurring temperature fluctuations.
• Known coolants for microprocess engineering include, for example, fluidic heat exchangers such as microcrossflow or Counterflow heat exchanger with a large number of fluid channels connected in parallel. These often have a microstructuring of the fluid channels, which can be expected on the one hand due to the large specific heat transfer area that results and the short heat transfer paths to be bridged, a high specific heat transfer rate.
• fluidic heat exchangers such as microcrossflow or Counterflow heat exchanger with a large number of fluid channels connected in parallel.
• the object of the invention is to propose a fluidic micro heat exchanger for the transfer of high area-specific amounts of heat, which does not have the limitations and disadvantages of the aforementioned systems and which is characterized in particular by a low flow resistance for a fluidic temperature control medium.
• the invention preferably also has a specific heat quantity dissipation that remains constant over a predetermined heat transfer range and a temperature level that remains constant over the surface.
• Another object of the invention is to propose a fluid cooler for an electronic component.
• micro heat exchanger according to the first and a use according to the seventh claim solved.
• the dependent claims referring to these represent advantageous refinements of the micro heat exchanger.
• the micro heat exchanger comprises the aforementioned heat transfer area, one supply channel structure and one discharge channel structure each for at least one heat transfer medium in the micro heat exchanger and a number of passages as the only connection for each heat transfer medium between the supply and discharge channel structures.
• the heat transfer area comprises, as an alternative to a heat transfer component between the heat energy source and the aforementioned heat transfer medium, preferably a heat transfer surface, more preferably an external heat transfer surface of the micro heat exchanger for connecting a component to be temperature-controlled with the aforementioned heat energy source.
• the connection can be made by a non-positive, positive or material connection, the heat transfer in positive and positive connections can be improved by a heat coupling medium such as a thermal fluid or thermal paste.
• a cohesive connection is carried out, for example, by soldering or gluing in the context of a material composite and, if the thermal conductivities and heat capacities of the materials used are coordinated, is similar to the aforementioned embodiment with a one-piece heat transfer component.
• An essential feature of the invention relates to the arrangement of the inlet and outlet channel structures for each heat transfer medium and the passages to one another.
• the aforementioned channel structures are intertwined in an alternating order and have separating walls which are bridged by the passages.
• the dividing walls like the channel structures, preferably extend over the entire heat transfer area, the passages being connected in parallel in large numbers as far as possible into the heat transfer area will.
• the separating walls are preferably as long as possible, the passages being distributed over the entire length.
• the dividing wall preferably also has a constant thickness over the entire length in which it is bridged by passages. As advantageous as preferably, all passages have the same dimensions with regard to cross section, length and relative arrangement to the heat transfer area.
• a first advantage of this design is that a high branching of the heat transfer medium flow in the channel structures and a further, i.e. even higher branching of the heat transfer medium flow in the passages, the specific area available for heat transfer is significantly increased, the maximum possible heat transfer in the passages being possible. Since the passages also expose themselves in the heat transfer area, in the same way over the entire heat transfer area, heat transfer takes place consistently predominantly in the passages in an advantageously practically uniform manner over the entire heat transfer area. Additional masses for temperature compensation in the heat transfer area, which would not only disadvantageously increase the heat transfer paths to or from the heat transfer medium and the power losses, but also increase the structural dimensions of the micro heat exchanger, are therefore not required or only to a significantly lesser extent.
• the passages and the channel structures in summa preferably have a larger cross section than the inlets and outlets of the micro heat exchanger, the passage cross sections in summa more preferably exceeding the summed up channel cross sections of the inlet or outlet. More preferably exceeds the length of each passage is by no means five times, more preferably twice its maximum cross-sectional dimension. It is essential, however, that the dimensions of the passages are designed in such a way that a starting flow that is not hydrodynamically and thermally developed is established.
• this three-dimensional, locally non-formed start-up flow has a flow vector with an additional component perpendicular to the heat-transferring wall, which locally increases the heat transfer between the wall and the fluid.
• the flow resistance remains low in this area due to the dimensions of the passages. If there is predominantly a laminar flow in the inlet and outlet channels, the heat transfer is advantageously concentrated even more strongly on the areas of the passages.
• micro heat exchanger essentially depend on the intended use, whereby they preferably adapt to the geometric dimensions of the components to be cooled, such as an adapted microreactor or an electronic component, the fineness of the channel structures, fluid guides, passages and walls being consistent determines the application and the specific amount of heat to be transferred.
• the range of size and fineness is primarily limited by the manufacturing process, whereby the flow through the heat transfer fluid must always be guaranteed. For example, minimal contamination or inhomogeneities in the fluid must not lead to blockages in the fluid guides (possible limitation of the fineness downwards).
• the manufacturing of the structures in the micro heat exchanger involves mechanical cutting or embossing, erosive (e.g. electrical, thermal or mechanical) or chemically caustic manufacturing processes, but also injection molding processes, deposition processes (e.g. galvanic) ), known microstructuring methods or a combination of the aforementioned methods.
• erosive e.g. electrical, thermal or mechanical
• chemically caustic manufacturing processes but also injection molding processes, deposition processes (e.g. galvanic) ), known microstructuring methods or a combination of the aforementioned methods.
• micro heat exchangers for the temperature control of chemical reactions, for example in a microreactor, or of physical or electronic processes, for example in an electronic circuit, a light source (for example incandescent lamp, discharge processes, etc.) or in a shield for a heat or cold source (protective shield without temperature control of the source itself) within the scope of the invention.
• the micro heat exchanger is attached from the outside to one or more or on all sides of a corresponding device for carrying out the above-mentioned processes or is integrated in this device, the respective heat transfer area with the passages in the micro heat exchanger not only on one side but also on both sides can be connected to a channel structure.
• Ia and b a basic arrangement of the inlet and outlet channel structures and the passages of a first embodiment in a perspective view and in a plan view
• FIGS. 2a and b show a basic arrangement of the inlet and outlet channel structures and the passages of a second embodiment in a perspective representation and in a top view
• FIGS. 4a and b show two sectional representations of the micro heat exchanger shown in FIG. 3 orthogonal to the inlet and outlet channel structures, 5 shows a sectional representation corresponding to FIGS. 4 a and b of an alternative structural design,
• FIGS. 4 a and b shows a sectional illustration corresponding to FIGS. 4 a and b of an alternative structural design for use as a fluid cooler for electronic components on a printed circuit board
• FIG. 7a to d are top views of the structured foils of a micro heat exchanger according to a second embodiment
• FIG. 8 shows a sectional view of the embodiment shown in FIG. 7 a to d.
• FIGS. 1a and b Exemplary arrangements of the inlet duct structures 1, outlet duct structures 2 and the passages 3 via the separating walls 4 are shown in principle in FIGS. 1a and b.
• the two channel structures 1 and 2 are formed in an alternating sequence by alternating parallel channels which, arranged in one plane, each have a distribution volume 5 and 6 for the inlet 7 and outlet 8.
• the separating walls are approximately the same thickness over the entire wall length, the bridging passages having the same dimensions as possible in all passages in order to achieve the same or similar flow conditions and only opening into the channel structures and not into the distribution volumes.
• the flow directions 9 of the heat transfer medium through the arrangement are shown by a number of arrows.
• the heat transfer medium changes several times back and forth between the aforementioned sections of the channel structures 1 and 2 during the flow through the arrangement, a quantity of heat being emitted or absorbed at each passage. It is irrelevant and in any case within the scope of this invention whether the inlet channel structure 1 and the outlet channel structure 2, as in FIG. 2a, are only aligned with one another in the same channel through a barrier 10, while the adjacent channel is closed on both sides with the partial sections and are only connected via passages 3 to the aforementioned inlet and outlet channel structures 1 and 2 or, as shown in FIG. 2b, the arrangement of the inlet and outlet channel structures 1 and 2 as in FIGS. 1a and b or also in FIGS. 3a and b are arranged alternately. In the variant shown in FIG.
• part of the barriers 10 takes on the function of the separating walls 4.
• the temperature in the heat transfer medium also changes with each flow of passengers.
• the aim of the second embodiment is to achieve the highest possible thermal efficiency with high surface-specific performance and low flow resistance.
• the passage length corresponds to the bridging distance (thickness) of the walls 4.
• the passage cross-section is dimensioned such that on the one hand the lowest possible flow resistance occurs, on the other hand the highest possible heat transfer is made possible directly and not indirectly via additional elements such as lateral cross-sectional boundaries or cooling fins to the adjacent heat transfer areas 13 (cf. for example Fig. 4a) . Consequently, the cross-section of the passages is chosen to be as large as possible.
• the ratio of width / height of the cross section in favor of the largest possible heat transfer area directly to the just extending heat transfer areas is as large as possible, ie over 1, preferably over 3, more preferably over 5.
• the passages are as shown in Fig. Ia and 2a , limited by webs (placed on the walls 4 between the passages 3). These act like spacers to the heat transfer areas not shown in FIGS. 1a and 2a and correspond in height to those of the passage cross sections. They serve as lateral boundaries of the passages and basically represent a flow barrier. Consequently, these webs are kept as narrow as possible in their lateral dimensions and preferably have a maximum of 50% of the width of the adjacent passages. Due to the desired large ratio of width / height of the passages, the heat transfer predominantly takes place directly into the heat transfer areas, while only a small amount of heat is transferred via the lateral surfaces of the webs.
• the webs are not designed as cooling fins, which absorb the majority of the amount of heat transferred and then pass them on via the cooling fin base, ie indirectly to the heat transfer areas 13 (see, for example, FIG. 4 a).
• the webs unlike cooling fins, do not play a significant role in heat transfer and can therefore also consist of a poorly heat-conducting material.
• the aforementioned length of the plurality of passages which is small in comparison to the cross section, is a parallel connection of a plurality of inlet flows.
• inlet currents As the flow path increases, a steady state of flow with a heat-insulating boundary layer, ie the length of a passage increases, the heat transfer efficiency decreases, but also the flow resistance.
• a short length consequently equally preferably gives high heat transfer and low flow resistance.
• the residence time of the heat transfer fluid and the Graetz number are very short, which leads to an increase in the Nusselt number. Due to this parallel connection of the passages and the short passage length, the pressure loss is low. Typical dimensions of the
• Passages are e.g. 0.05 to 0.2, preferably 0.1 to 0.15 mm for the height, 0.5 to 1.5 mm, preferably 0.8 to 1.0 mm for the passage width and 0.3 to 1.0 mm, preferably 0.5 to 0.6 mm for the passage length or the thickness of the walls 4.
• the micro heat exchanger comprises the carrier plate 11 shown in FIG. 3a with the aforementioned inlet and outlet channel structures 1 and 2, the separating wall 4 and the distribution volumes 5 and 6 as incorporated recesses and the inlet and outlet 7 and 8 as openings.
• a circumferential groove 14 for receiving an adhesive and / or sealant 15 for an overlying cover film 11 is provided on the carrier plate around the aforementioned depressions.
• the passages 3, on the other hand, are incorporated into the cover film 12 as grooves that are oriented orthogonally to the channel structures 1 and 2 (for example mechanically), their extension area forming the aforementioned heat transfer area 13.
• the corresponding cross section orthogonal through the channel structures 1 and 2 and at the height of the passages 3 is shown in Fig.4a.
• the carrier plate 11 is preferably made from a bad and the cover sheet 12 from a good thermal conductor material.
• This choice of material has the advantage that the heat transfer takes place in the passages while it is in the channel structures is prevented as far as possible.
• a thermal insulation film with openings is congruently inserted between the carrier plate and the cover sheet and is congruent with the passages, which can also be used to weld the carrier plate to the cover film.
• a different thermal expansion behavior and an associated tendency to shear stresses or relative movements can be expected in the aforementioned pairing of materials, which complicates permanent welding or makes the aforementioned additional circumferential groove 14 necessary for bonding or pressing together.
• a form-fitting degree engaging in the circumferential groove 14 can also be provided to prevent it from sliding sideways on the cover film. In a further embodiment variant, this degree can also be designed as a press fit for joining the carrier plate and cover film.
• FIG. 4b shows a heat transfer area 13 with two-sided arrangement of two of the aforementioned heat exchangers. It is particularly suitable as a counterflow heat exchanger in connection with the aforementioned second embodiment (cf.
• Carrier plate 11 and cover film 12 preferably consist of the same or thermally connectable materials, preferably a metal, a metal alloy or a plastic, and are preferably connected to one another in a fluid-tight manner using a diffusion welding process.
• the unstructured base region 17 of the carrier plate 11 was made as thin as possible and thus elastically flexible in the context of this exemplary embodiment.
• the height of the walls 4 and thus the depth of the duct preferably exceeds structures 1 and 2 the strength of the floor area, preferably by twice.
• the inlets and outflows not shown in FIG. 5 do not have to penetrate the floor area as in the exemplary embodiments shown in FIGS. 3 and 4, but can also open, for example, at the front through the carrier plate 11 or through the cover film 12 into the micro heat exchanger .
• FIGS. 4 a and b and 5 show a sectional illustration corresponding to FIGS. 4 a and b and 5 of an alternative structural design for use as a fluid cooler for electronic components on a printed circuit board.
• the micro heat exchanger shown has only perforated or unstructured plates or foils.
• the carrier plate 11 is made up of a base plate 19 which is unstructured except for the openings for the inlet and outlet 7 or 8 (corresponding to the floor area) and an attached, in the area of the inlet channel structures 1, outlet channel structures 2 and the distribution volumes 5 and 6 for the inlet 7 or drain 8 perforated structure plate 20 assembled.
• the cover film 12 is composed of an unstructured heat-conducting film 21 and a structural film 22 which is open in the area of the passages.
• the arrangement of the openings in the structural film and the structural plate follows the aforementioned design principles for the fluid guides (channel structures with walls, passages, distribution volumes etc.) in the aforementioned exemplary embodiments and are shown by way of example in FIGS. 3a and b.
• Diffusion welding as a tried and tested joining process for the layer structure of the micro heat exchanger.
• the micro heat exchanger shown in FIG. 6 is placed on a circuit board 23, the supply and discharge lines 7 and 8 projecting through the circuit board.
• the electronic component 24 itself comprises an electronic circuit 25, such as a processor, which produces the amount of heat to be dissipated and is placed directly on the heat-conducting film 21.
• the electronic component further comprises a housing 26 and electrical contact strands 27 for connecting the circuit to conductor tracks on the circuit board.
• FIG. 7a to d and 8 show a second embodiment of the micro heat exchanger. It is essential that the supply channel structure 1 and the discharge channel structure 2, each with associated distribution volumes 5, 6, extend over at least two, in the exemplary embodiment three, levels. As with the aforementioned design variants, the heat transfer area 13 and the passages 3 are integrated in the cover film 12 (cf.
• FIG. 7d there is a film 29 with the inlet channel structure 1 and the outlet channel structure 2 under the cover film, comprising a multiplicity of channels arranged parallel to one another (cf. FIG. 7c).
• the inlet and outlet channel structures are intertwined as channels in an alternating order.
• the passages 3 in the cover film 12 and the inlet channel structure 1 and the outlet channel structure 2 in the film 29 are preferably oriented orthogonally to one another with their respective open channel structures on one another (cf. FIGS. 7c and d and 8).
• the distribution volumes 5 and 6 for the inlet 7 and the outlet 8 are not arranged in a level to the side of the channel structures 1 and 2, but in at least one separate level below the level with the channel structures 1 and 2. They like the channel structures, preferably consist of one film 29 per level processed channels.
• the channels per level that is to say also per film, are - as shown in FIGS. All channel structures in the foils have connection openings 28, ie openings through the foils 29 in the bottom region of the channels, which selectively connect the respective distribution volumes only to the respective underlying distribution volumes with the same affiliation to inlet 7 or outlet 8.
• a heat transfer medium for example water or oil, consequently flows through all levels after passing through the inlet and, after passing through passages 3, enters the channel fractions belonging to the outlet. These are forwarded again through all levels in the reverse order to sequence 8 (cf. Fig. 8).
• the flow path from the inlet via the distribution volumes (inlet) 5 (with passage through the connection openings 28), inlet duct structure 1, passages 3 to the outlet duct structures 2 is exemplified in FIG. 8 with a branching arrow
• a feature of this embodiment relates to the layout of the channels in the levels.
• the channels preferably intersect perpendicularly (see FIGS. 7 a to c) with the channels of the respectively adjacent plane, the foils or planes with each plane in the direction of the heat transfer area (13) comprising an increasing number of channels, which are preferably becoming ever finer.
• the channels are arranged in an alternating sequence, preferably parallel to one another (cf. FIGS. 7 a to c) and in each case connected to the respective channels of the supply channel structure or discharge channel structure via the connection openings 28.
• the first of the foils 29 and the cover foil 12 applied to them comprise the actual heat transfer structure, while the remaining foils 29 lying below comprise the distribution volumes.
• the foils are preferably made of a metal that is corrosion-resistant for the cooling medium such as water (e.g. VA steel, brass, etc.) and are connected to each other using a diffusion welding process.
• the particular advantage of this second embodiment lies in the good scalability of the design.
• the inlet and outlet of the micro heat exchanger is branched at each level, i.e. By adding or deleting, practically any branching can be realized with fine branching gradations.
• the material in the heat transfer area is not necessarily a very must have good thermal conductivity and can therefore be selected in favor of higher corrosion resistance and thus the service life.
• the range of materials for the micro heat exchanger not only extends to corrosion-resistant metals, but also other materials such as glasses, plastics or ceramics.

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• Physics & Mathematics (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Computer Hardware Design (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Power Engineering (AREA)
• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
• Heat-Exchange Devices With Radiators And Conduit Assemblies (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)

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• 2005
  • 2005-12-09 DE DE102005058780A patent/DE102005058780A1/de not_active Ceased
• 2006
  • 2006-12-08 KR KR1020087002055A patent/KR20080075078A/ko not_active Withdrawn
  • 2006-12-08 JP JP2008543742A patent/JP5135225B2/ja not_active Expired - Fee Related
  • 2006-12-08 WO PCT/EP2006/011849 patent/WO2007065705A1/de not_active Ceased
  • 2006-12-08 EP EP06829445.3A patent/EP1958254B1/de not_active Not-in-force
• 2008
  • 2008-02-08 US US12/069,397 patent/US8047273B2/en active Active

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