Process of manufacturing a coldplate for semiconductor cooling applications and coldplate

Abstract

The present invention relates to a process of manufacturing a coldplate (100) for semiconductor cooling applications, with the steps • providing a base plate (102), • 3D screen printing a cooling structure layer (104) on top of the base plate (102) with a build rate between 15 and 8,500 cm³ per hour to form a first three-dimensional cooling structure (106) within the coldplate (100) having critical dimensions between 25 and 200 µm and an aspect ratio between 1 and 80, wherein the first three-dimensional cooling structure (106) comprises at least one area (108) with a microstructure including a network of channels (110) for guiding a cooling agent, and two or more three-dimensional features (112) which contribute to the formation of boundaries of the channels of the network of channels (110).

Description

[0001] CR0006P-WG

[0002] Process of manufacturing a coldplate for semiconductor cooling applications and coldplate

[0003] The invention relates to the field of semiconductor devices and more precisely to the cooling of semiconductor devices. More specifically, a process of manufacturing a coldplate for semiconductor cooling applications is disclosed as well as a coldplate for semiconductor cooling applications.

[0004] Background of the Disclosure

[0005] In semiconductor devices, heat management is a significant contributor to improving performance. Overheating of a semiconductor device typically negatively impacts device performance, efficiency and reliability: High temperatures lead to an increase in leakage currents, which result in power losses and an increase in sheet resistance due to self-heating degradation. Higher device temperature and temperature swings can be directly correlated to a reduction in the mean time before failure. In addition to silicon logic devices, such as central processing units (CPUs), graphics processing units (GPUs), tensor processing units (TPUs), field programmable gate arrays (FPGAs) and other application-specific integrated circuits (ASICs), this trend of rising heat fluxes and their negative impact on performance and reliability also holds for power electronic, optoelectronics and RF electronics, on silicon and other semiconductors such as GaAs, SiC, GaN, etc. any of these examples are exemplary embodiments.

[0006] Coldplates for cooling semiconductor elements and devices usually comprise very small sized cooling structures. Moreover, cooling structures can be formed and configured to match the power map of specific semiconductor elements or devices for ensuring a very high cooling performance based on the specific power map of the semiconductor element or device. This can result in very complex regular and / or irregular structures. Manufacturing of such structures can be challenging due to the complexity and small size. Hence, there is a need for suitable manufacturing processes allowing manufacturing of coldplates which fulfill the aforementioned requirements,

[0007] The present application seeks to provide a process of manufacturing a coldplate for semiconductor cooling applications with which the above-mentioned structures can be manufactured precisely and efficiently. The present application further seeks to provide a respective coldplate for semiconductor cooling applications that is suitable for sufficiently

[0008] August 28, 2025 1 / 44 cooling semiconductor devices or elements.

[0009] Brief Summary of the Disclosure

[0010] This object is achieved by the subject matter of the independent claims. Advantageous embodiments are defined in the dependent claims, in this description and in the Figures.

[0011] An observation underlying the present disclosure is that the above-mentioned complex and small structures cannot be manufactured satisfactorily by standard manufacturing techniques, such as CNC milling or skiving.

[0012] To address this issue and provide a suitable solution, a process of manufacturing a coldplate for semiconductor cooling applications is provided, the process comprising the following steps:

[0013] • Providing a base plate; and

[0014] • 3D screen printing at least one cooling structure layer on top of the base plate with a build rate, including depositing and curing the at least one cooling structure layer, between 15 and 8,500 cm3per hour (in words between fifteen and eight thousand five hundred) to form a first three-dimensional cooling structure within the coldplate having critical dimensions between 25 and 200 pm and an aspect ratio between 1 and 80, wherein the first three-dimensional cooling structure comprises at least one area with a microstructure including a network of channels for guiding a cooling agent, and two or more three-dimensional features which contribute to the formation of boundaries of the channels of the network of channels.

[0015] By using 3D screen printing, i.e. depositing and curing at least one or multiple layer / s, at least for the step of forming the at least one cooling layer structure of a coldplate for semiconductor applications and by choosing the parameters of the 3D screen printing and the cooling structure, namely build rate, critical dimensions, and aspect ratio, as specified above, the inventors have established a solution that enables precise and efficient manufacturing of coldplates for semiconductor cooling applications. In other words, by this process coldplates can be produced with sufficient economically efficient throughput which coldplates are suitable for being used to efficiently cool semiconductor devices and / or elements.

[0016] Due to the complexity and small size, known manufacturing techniques are not precise enough or do not offer sufficient design freedom for manufacturing the cooling structures of coldplates in a way that the coldplates work as they should regarding their cooling performance and / or do not

[0017] August 28, 2025 2 / 44 have sufficient throughput, when trying to manufacture small and precise enough structures.

[0018] 3D screen printing, which can also be referred to as additive screen printing, can advantageously combine the principles of traditional screen printing with additive manufacturing techniques to create three-dimensional structures. It can be used for various applications, including electronics, biomedical devices, and advanced manufacturing.

[0019] In preparation of the 3D screen printing, an initial pre-step can be the design preparation. In this pre-step, a desired 3D structure can be designed, e.g., using CAD (Computer Added Design) softwares. A resulting 3D model can then be digitally sliced into a plurality of layers, which will guide the 3D screen printing process. Each layer of the 3D model can be converted into a 2D pattern that can be printed / deposited sequentially.

[0020] The next pre-step can be stencil preparation. In this step the stencils are created for each layer of the 3D model. For example, a photosensitive emulsion can be applied to a screen and exposed to UV light through a film positive of the design. Exposed areas harden, while unexposed areas are washed away, creating a stencil for each layer.

[0021] The next pre-step can be the material preparation. The materials used can vary depending on the application. The material’s viscosity can be important for proper layer formation. Thicker pastes can be used for building up layers, while thinner pastes can be used for applying finer details.

[0022] After that, the 3D screen printing process can be performed. The 3D screen printing involves depositing and curing material layer by layer to build up the 3D structure. Each layer corresponds to a stencil, and the material is deposited through the stencil onto the substrate.

[0023] After all layers have been 3D screen printed, a final curing or more precisely sintering process can be performed as a post-step to solidify and stabilize the entire structure.

[0024] Hence, the process can involve not only a curing after depositioning of each layer, as part of the 3D screen printing step / s, but also a (final) curing of the coldplate in the form of sintering. The curing between depositioning the individual layers is to solidify the layer to a certain extent in order to allow depositioning of the next layer on top thereof. (Final) Curing or more precisely sintering after 3D screen printing joins the particles in the paste into a solid object.

[0025] In an embodiment, the process can comprise the additional step of providing a cover layer on top of the first three-dimensional cooling structure, after 3D screen printing the first three- dimensional cooling structure. The cover layer can be part of the coldplate or can be part of an external component or device, such as the device or element to be cooled. The cover layer can be or form a cover and / or a manifold and / or lid and / or connection structure to an inlet or outlet.

[0026] August 28, 2025 3 / 44 For example in one coldplate assembly, a coldplate having a base plate and a three- dimensional cooling structure can be 3D screen printed, subsequently sintered, for example into solid copper, and then bonded to a manifold, such as a copper manifold, using e.g. brazing or diffusion bonding, such that coolant can flow via a tube or other connector or supply into and out of the coldplate.

[0027] In another example, a 3D screen printed coldplate having a base plate and a three-dimensional cooling structure can be provided with a cover layer directly 3D screen printed on top of the cooling structure. This cover layer can function as a roof or cover over the cooling features and / or help to define the inlets and outlets for cooling agent. The cover layer can be a cover and / or a manifold and / or lid and / or connection structure.

[0028] In an embodiment, the base plate can be 3D printed, i.e. , by depositing and curing at least one or multiple base plate layer / s. Thus, a monolithic base plate and three dimensional cooling structure can be formed, which can be advantageous for providing a stable and leak tight coldplate for semiconductor cooling applications.

[0029] In an embodiment, the at least one cooling structure layer can be printed directly or indirectly on top of the base plate. Printing the at least one cooling structure layer directly on top of the base plate, i.e. on a top surface of the base plate, can be advantageous for achieving a stable bonding between the base plate and the at least one cooling structure. However, it is also possible to print the at least one cooling structure indirectly onto the base plate. In this case, an additional layer or element can be provided between the base plate and the at least one cooling structure.

[0030] The at least one cooling structure layer, each layer of the three-dimensional cooling structure, and / or each layer of the complete coldplate can be printed, including depositing and curing the at least one or each cooling structure layer, with a build rate between 25 and 7,500 cm3per hour, or between 50 and 7,000 cm3per hour, or between 100 and 6,500 cm3per hour, or between 150 and 6,000 cm3per hour, or between 200 and 5,000 cm3per hour, or between 250 and 3,500 cm3per hour, or between 500 and 2,000 cm3per hour, or with a build rate between 700 and 1 ,750 cm3per hour. The build rate can be at least 15 cm3per hour, or at least 25 cm3per hour, or at least 50 cm3per hour, or at least 100 cm3per hour, or at least 150 cm3per hour, or at least 200 cm3per hour, or at least 250 cm3per hour, or at least 500 cm3per hour, or at least 700 cm3per hour. The build rate can 8,500 cm3per hour or less, or 7,500 cm3per hour or less, or 7,000 cm3per hour or less, or 6,500 cm3per hour or less, or 6,000 cm3per hour or less, or 5,000 cm3per hour or less, or 3,500 cm3per hour or less, or 2,000 cm3per hour or less, or 1 ,750 cm3per hour or less.

[0031] Alternatively or in addition, the at least one cooling structure layer, each layer of the three-

[0032] August 28, 2025 4 / 44 dimensional cooling structure, and / or each layer of the complete coldplate can be screen printed, including depositing and curing the at least one or each cooling structure layer, with a build rate of between 25 and 4,500 cm3per hour, or between 40 and 4,000 cm3per hour, or between 50 and 3,500 cm3per hour, or between 60 and 3,000 cm3per hour, or between 70 and 2500 cm3per hour, or between 80 and 2000 cm3per hour, or between 90 and 1 ,500 cm3per hour, or between 100 and 1 ,000 cm3per hour. The build rate can be at least 15 cm3per hour, or at least 25 cm3per hour, or at least 40 cm3per hour, or at least 50 cm3per hour, or at least 60 cm3per hour, or at least 70 cm3per hour, or at least 80 cm3per hour, or at least 90 cm3per hour, or at least 100 cm3per hour. The build rate can be 8,500 cm3per hour or less, or 4,500 cm3per hour or less, or 4,000 cm3per hour or less, or 3,500 cm3per hour or less, or 3,000 cm3per hour or less, or 2,500 cm3per hour or less, or 2,000 cm3per hour or less, or 1 ,500 cm3per hour or less, or 1 ,000 cm3per hour or less. Optionally, the build rate may refer to a build rate of one printing machine.

[0033] In an embodiment, several printing machines can be utilized simultaneously. Using several machines may contribute to providing a build rate of between 50 and 7,500 cm3per hour, or between 80 and 7,000 cm3per hour, or between 100 and 6,500 cm3per hour, or between 120 and 6,000 cm3per hour, or between 140 and 5,000 cm3per hour, or between 160 and 3,500 cm3per hour, or between 180 and 2,000 cm3per hour, or between 200 and 1 ,750 cm3per hour. The build rate can be at least 30 cm3per hour, or at least 80 cm3per hour, or at least 100 cm3per hour, or at least 120 cm3per hour, or at least 140 cm3per hour, or at least 160 cm3per hour, or at least 180 cm3per hour, or at least 200 cm3per hour. The build rate can be 8,500 cm3per hour or less, or 7,500 cm3per hour or less, or 7,000 cm3per hour or less, or 6,500 cm3per hour or less, or 6,000 cm3per hour or less, or 5,000 cm3per hour, or 3,500 cm3per hour, or 2,000 cm3per hour or less, or 1 ,750 cm3per hour or less.

[0034] Critical dimensions for semiconductor coldplates here and as known in the present technical field refer to horizontal 2D structures of the cooling structure features, such as channels and elements, in particular cooling structure widths of the channels for cooling agent flow and features forming the channels. Critical dimensions do not include the thickness / heights of the cooling structure layer or other layers of the coldplate. Critical dimensions therefore refer to the 2D design, size and shape of the three-dimensional structure to ensure proper heat dissipation. These dimensions are crucial in determining the efficiency and effectiveness of the coldplate in cooling semiconductor devices.

[0035] In other words, critical dimensions can be those that are essential for a part's functionality, assembly, and performance. The critical dimensions as specified by the inventors have been determined by considering design requirements, manufacturing capabilities, material properties, and application-specific needs of coldplates for semiconductor cooling applications. Ensuring

[0036] August 28, 2025 5 / 44 that these dimensions are met and maintaining control over critical dimensions is key to producing high-quality, reliable parts.

[0037] Providing a three-dimensional cooling structure within the coldplate having critical dimensions between 25 and 200 pm can mean that the 3D screen-printing process can be performed with a resolution between 25 and 200 pm to realize and fulfill such critical dimensions.

[0038] In an embodiment, the coldplate, in particular the three-dimensional cooling structure, can have critical dimensions between 30 and 150 pm, more preferably between 40 and 100 pm and especially 50 pm. The coldplate or three-dimensional cooling structure can comprise critical dimensions of at least 25 pm, or at least 30 pm, or at least 40 pm, or of 50 pm. Additionally or alternatively, the coldplate or three-dimensional cooling structure can comprise critical dimensions of 200 pm or less, or of 150 pm or less, or of 100 pm or less.

[0039] The aspect ratio can be understood as a mathematical ratio that describes the proportional relationship between the three-dimensional cooling structure’s width and height.

[0040] In an embodiment, the aspect ratio of the three-dimensional cooling structure can be between 2 and 70, or between 5 and 65, or between 10 and 60, or between 20 and 55. The aspect ratio can be at least 2, or at least 5, or at least 10, or at least 20. The aspect ratio can be 70 or less, or 65 or less, or 60 or less, or 55 or less.

[0041] In an embodiment, the aspect ratio of the three-dimensional cooling structure can be between 2 and 70, or between 3 and 65, or between 4 and 60, or between 5 and 55. The aspect ratio can be at least 2, or at least 3, or at least 4, or at least 5. The aspect ratio can be 70 or less, or 65 or less, or 60 or less, or 55 or less, or 50 or less.

[0042] In an embodiment, the aspect ratio may be between 2 and 21, or between 2.5 and 19, or between 3 and 17, or between 3.5 and 15. The low aspect ratio may be at least 2, or 2.5, or 3, or 3.5. The low aspect ratio may be 21 or less, or 19 or less, or 17 or less, or 15 or less.

[0043] Build rate, critical dimensions and aspect ratio are each interrelated and dependent to each other. For example, a too high build rate and / or too high aspect ratios can be detrimental to ensuring very small critical dimensions. Critical dimensions of the cooling structure can be small if the aspect ratio is sufficiently low. Inventors of the present solution have considered relationships and dependencies between these parameters and have implemented optimal values for coldplates for semiconductor cooling applications. It is to be mentioned that for other applications respective values and critical parameters can be substantially different due to application requirements and interrelations between the parameters.

[0044] In an embodiment, the microstructure of the first three-dimensional cooling structure can

[0045] August 28, 2025 6 / 44 CR0006P-WG comprise three-dimensional features with protruding or projecting elements that extend into the layer deposition direction.

[0046] Typical cooling agents can be, but are not limited to:

[0047] Water

[0048] Water-glycol mixtures;

[0049] Dielectric fluids;

[0050] Mineral oils;

[0051] Specialty coolants.

[0052] Refrigerants (HFO, CFG, etc.).

[0053] In an embodiment, the cover layer can serve the purpose to directly cover the cooling structure. Alternatively, the cover layer can indirectly cover the cooling structure.

[0054] According to an embodiment, the first three-dimensional cooling structure can be formed by 3D screen printing at least two or multiple cooling structure layers, directly or indirectly, on top of each other. This means that the coldplate can have more than one three-dimensional cooling structure. For example, the coldplate can have a sandwich structure with multiple three- dimensional cooling structures between the base and the cover plate. The coldplate can have more than one three-dimensional cooling structure laterally adjacent to each other.

[0055] The process can further comprise a drying or curing step, wherein a drying or curing time is between 10 s and 30 s. The drying or curing step can occur after printing at least one cooling structure layer. The drying or curing time can be between 12 s and 25 s, or between 15 s and 20 s. The drying or curing step serves the purpose of curing and stabilizing material properties and ensures dimensional stability and allows secure depositing of subsequent layers.

[0056] According to an embodiment, a 3D screen printing time to print at least one cooling structure layer is between 0.1 and 3s.

[0057] Alternatively or in addition, the process can comprise a drying or curing step, wherein a drying or curing time is between 2 s and 200 s. The drying or curing step can be performed after printing at least one cooling structure layer. The drying or curing time can be between 2 s and 200 s, or between 5 s and 180 s, or between 7.5 s and 160 s, or between 10 s and 150 s. A minimum drying or curing time may be 2 s, or 5 s, or 7.5 s or 10 s. A maximum drying or curing time may be 200 s, 180 s, 160 s or 150 s. The drying or curing step can serve the purpose of curing and stabilizing material properties and contribute to ensuring dimensional stability and

[0058] August 28, 2025 7 / 44 CR0006P-WQ allows securing depositing of subsequent layers.

[0059] According to an embodiment, a 3D screen printing time to print and / or to deposit at least one cooling structure layer can be between 0.1 s and 100 s, or between 1 s and 75 s, or between

[0060] 2 s and 60 s, or between 3 s and 50 s. A minimum printing time may be 0.1 s, or 1 s, or 2 s or

[0061] 3 s. a maximum printing time may be 100 s, or 75 s, or 60 s or 50 s.

[0062] This can increase the efficiency of the manufacturing process due to the fact that a sufficient number of cooling structure layers, and thus a sufficient number of coldplates, can be manufactured in one time interval, e.g. per hour.

[0063] In an embodiment, at least one further three-dimensional cooling structure is formed within the coldplate by providing, preferably 3D screen printing, an intermediate base plate on top of the first three- dimensional cooling structure, and

[0064] 3D screen printing at least one, at least two or multiple further cooling structure layers on top of the intermediate base plate, the intermediate base plate preferably being provided with at least one inlet and / or at least one outlet for distributing cooling agent between the cooling structures.

[0065] The at least one further three-dimensional cooling structure can comprise at least one area with a microstructure including a network of channels for guiding a cooling agent, and / or two or more three dimensional features which contribute to the formation of boundaries of the channels of the network of channels. Microstructures of adjacent cooling structures can be different or similar to each other.

[0066] Providing at least one further three-dimensional cooling structure can increase the cooling efficiency of the coldplate.

[0067] In an embodiment, the coldplate is a metal coldplate, preferably a copper coldplate. Alternatively, other possible, but not limiting, materials can be copper carbon composites (e.g. with graphene, diamond, carbon nanowires). Such materials can match the coefficient of expansion to Silicon and increase the thermal conductivity. Further alternative materials can be silicon carbide as well as aluminum nitrite and / or aluminum.

[0068] To enhance the mechanical properties, the coldplate can comprise impurities comprising oxygen and / or carbon.

[0069] In the coldplates, a controlled amount of oxygen impurities can lead to the formation of oxides,

[0070] August 28, 2025 8 / 44 CR0006P-WQ which can enhance the mechanical strength and durability of the coldplate. For example, aluminum alloy containing small amounts of oxygen can form aluminum oxide, which improves wear resistance and hardness.

[0071] Similar to oxygen, carbon can also influence the mechanical properties of the coldplate. In some cases, carbon can increase the hardness and tensile strength, improving the durability of the coldplate under mechanical stress.

[0072] Regarding the cooling effect of the coldplate, the intentional use of oxygen and / or carbon impurities can influence the thermal conductivity of the coldplate.

[0073] Additionally, the impurities comprise oxygen between 0.005 and 0.009 wt.%, or 0.006 and 0.008, and / or comprise carbon between 0.020 and 0.030 wt.%, or 0.024 and 0.026 wt.%.

[0074] Alternatively or in addition, the impurities can comprise oxygen between 0.001 wt.% and 0.050 wt.%, or between 0.003 wt.% and 0.040 wt.%, or between 0.005 wt.% and 0.030 wt.%, and / or carbon between 0.001 wt.% and 0.050 wt.%, or between 0.003 wt.% and 0.040 wt.%, 0.005 wt.% and 0.025 wt.% and / or nitrogen between 0.00005 wt.% and 0.007 wt.%, or between 0.00008 wt.% and 0.006 wt.%, or between 0.0001 wt.% and 0.005 wt.%.

[0075] A minimum amount of oxygen may be 0.001 wt.%, or 0.003 wt.%, or 0.005 wt.%. A maximum amount of oxygen may be 0.050 wt.%, or 0.040 wt.%, or 0.030 wt.%. A minimum amount of carbon may be 0.001 wt.%, or 0.003 wt.%, or 0.005 wt.%. A maximum amount of carbon may be 0.050 wt.%, or 0.040 wt.%, or 0.025 wt.%. A minimum amount of nitrogen may be 0.00005 wt.%, or 0.00008 wt.%, or 0.0001 wt.%. A maximum amount of nitrogen may be 0.007 wt.%, or 0.006 wt.% or 0.005 wt.%.

[0076] These values can be chosen to achieve a balance between the advantages and potential drawbacks mentioned above.

[0077] According to an embodiment, the base plate and / or the cover layer can be provided with a build rate higher than the build rate by which the three-dimensional structure is provided. It can for example be between 1.5 and 10 times the build rate of the three-dimensional structure, or 2.0 to 8.0 times, or 3.0 to 6.0 times.

[0078] According to an embodiment, the base plate and / or the cover layer is provided by 3D screen printing, preferably with a build rate between 100 and 12,000 cm3per hour, or between 250 and 10,000 cm3per hour, or between 500 and 9,000 cm3per hour. Here, the build rate for the base plate and / or the cover layer can also be higher than for the three-dimensional structure.

[0079] August 28, 2025 9 / 44 Alternatively, the base plate and / or the cover layer are provided by metal injection molding or by pouring paste into a mold for a first base layer and scrape off residue to create a flat layer, and then remove the mold, or by using a metallic foil. The base layer may correspond to the base plate.

[0080] In embodiments, the base plate and / or the cover layer is provided as a separate part and is bonded to the at least one cooling structure layer, respectively. Bonding can be realized by brazing or copper-copper diffusion bonding. In other words, the term separate part can be understood in a way that the base plate and / or the cover layer are distinct from the at least one cooling structure layer.

[0081] This can provide more flexibility regarding the manufacturing of the parts.

[0082] The base plate, as well as the intermediate base plates, can be provided with at least one inlet and / or at least one outlet for guiding cooling agent to and / or from the cooling structure within the coldplate.

[0083] In an embodiment, the cover layer is provided with at least one inlet, at least one outlet, and / or multiple orifices for guiding cooling agent to and / or from the cooling structure within the coldplate.

[0084] Non-limiting examples for such orifices are holes or slits.

[0085] This embodiment can enable an easy guidance of the cooling agent.

[0086] According to an embodiment, the process comprises 3D screen printing at least one inlet and / or at least one outlet, preferably at least one inlet connector and / or at least one outlet connector, for distributing cooling agent to and / or from the three-dimensional cooling structures.

[0087] This embodiment can lead to a further improved manufacturing process as further parts, preferably the complete coldplate assembly, are manufactured by 3D screen printing.

[0088] The inlet connector can be the inlet of the base plate and / or the inlet of the cover layer and / or the inlet of the intermediate base plate and / or the inlet of a lid arrangement. The outlet connector can preferably be the outlet of the base plate and / or the outlet of the cover layer and / or the outlet of the intermediate base plate and / or the outlet of a lid arrangement.

[0089] The process can further comprise providing, for example 3D screen printing, a manifold structure within the coldplate for distributing cooling agent within the coldplate. The manifold structure can be provided on top of the cover layer.

[0090] As an alternative to 3D screen printing, metal injection molding can be used for providing,

[0091] August 28, 2025 10 / 44 especially manufacturing, the manifold structure within the coldplate.

[0092] In an embodiment, the process further comprises providing, for example 3D screen printing, a lid arrangement within the coldplate.

[0093] In one embodiment, the lid arrangement can have at least one inlet and / or at least one outlet, the lid arrangement can have a first lid with at least one inlet and a second lid with at least one outlet. The lid arrangement can be provided as an outer top layer of the coldplate. Optionally, the first lid may correspond to the cover layer. Optionally, the second lid may correspond to a most outer layer of the coldplate of other embodiments, wherein the most outer layer is configured to be arranged farthest away from the semiconductor arrangement, wherein in other embodiments, the most outer layer may be described as a lid arrangement.

[0094] In an embodiment, the process may comprise arranging the first three-dimensional cooling structure between the lid arrangement and the base plate. In this arrangement, the lid arrangement covers the first three-dimensional cooling structure, while the base plate supports the first three-dimensional cooling structure. This can contribute to providing a cavity for the first three-dimensional cooling structure to dissipate heat to a cooling agent flowing through the cooling structure.

[0095] In an embodiment, the first three-dimensional cooling structure is at least partially supported by the lid arrangement. To support the first three-dimensional cooling structure, the lid arrangement and the first three-dimensional cooling structure can be formed at least partially monolithic. For example, a portion of the first three-dimensional cooling structure can be coupled to the lid arrangement. This can contribute to providing a rigid coldplate, which can contribute to withstanding high pressures that could other wise cause the coldplate to burst.

[0096] In an embodiment, the process comprises providing the first three-dimensional cooling structure with an aspect ratio between 6 and 21 , or between 7 and 19, or between 8 and 17, or between 9 and 15. In this embodiment, a minimal aspect ratio can be 6, 7, 8 or 9, while a maximum aspect ratio can be 21 , or 19, or 17, or 15. Alternatively, the aspect ratio may be between 6 and 60, or between 7 and 55, or between 8 and 50, or between 9 and 45, or between 10 and 40, or between 10.5 and 35, or between 11 and 30. In the alternative, a minimal aspect ratio may be 6, or 7, or 8, or 9, or 10, or 10.5 or 11 , while a maximal aspect ratio may be 60, or 55, or 50, or 45, or 40, or 35, or 30.

[0097] A coldplate having such an aspect ratio can in some cases be difficult to manufacture, since the first three-dimensional cooling structure is prone to collapsing when being sintered. By providing a lid arrangement to support the first three-dimensional cooling structure, the first three- dimensional cooling structure is supported, which can contribute to facilitating the sintering

[0098] August 28, 2025 11 / 44 process while contributing to preventing collapsing of the first three-dimensional cooling structure.

[0099] In an embodiment, the process comprises providing the lid arrangement with at least one surface for bonding with the manifold. Additionally or alternatively, the surface for bonding with the manifold can be configured to be coupled with the manifold. Connecting the lid arrangement to the manifold can contribute to strengthening the lid arrangement and the manifold as both, the lid arrangement and the manifold, support each other. Furthermore, the surface for bonding with the manifold can contribute to facilitating a coupling of the manifold to the lid arrangement.

[0100] In an embodiment, the process comprises providing the lid arrangement with a thermal contact surface. Accordingly, the lid arrangement comprises another thermal contact surface, which increases the thermal contact surface to dissipate heat from or to the cooling agent. This can contribute to achieving good heat dissipation.

[0101] Alternatively, metal injection molding can be used for providing, namely manufacturing, the lid arrangement within the coldplate.

[0102] The benefit of the above-mentioned manufacturing steps of 3D screen printing the manifold structure and the lid arrangement can be seen in the further steps which are performed with the same method. This further enhances efficiency of the process and provides a stable and precisely manufactured structure.

[0103] The process can comprise the further step of curing the coldplate by sintering, thermal curing, UV curing, electron beam curing, chemical curing, microwave curing, induction curing, room temperature curing, or a combination thereof.

[0104] To ensure a high stability, leak-tightness and a high thermal conductivity, the material of the at least the first three-dimensional cooling structure, or the complete coldplate, can have a relative density of at least 95%, or at least 97%, or at least 99%, after curing. The relative density can be 99.99% or less.

[0105] Here, the relative density can be understood as the inversion of porosity and refers to the material of the manufactured product, e.g. the coldplate. For example, the relative density of at least 95% means that at most 5% voids are contained in the material after curing. By providing respective relative density, a coldplate can be provided that has optimal tightness for use of the coldplates to cool semiconductor devices and prevents unwanted diffusion.

[0106] Advantageously, the channels of the network of channels are interconnected, to allow efficient distribution of the cooling agent within the cooling structure.

[0107] August 28, 2025 12 / 44 According to an embodiment, the two or more three-dimensional features comprise protrusions, regularly shaped fins, irregularly shaped fins, walls, pins and / or pillars.

[0108] By means of the protrusions, the heat can be transferred more efficiently.

[0109] The at least one cooling structure layer can have a thickness between 10 pm and 300 pm, or between 25 pm and 250 pm, or between 40 pm and 200 pm, or between 50 pm and 160 pm. The at least one cooling structure layer can have a thickness or 10 pm or more, or 25 pm or more, or 40 pm or more, or 50 pm or more. The at least one cooling structure layer can have a thickness of 300 pm or less, or 250 pm or less, or 200 pm or less, or 160 pm or less.

[0110] Each cooling structure layer has the above-specified thickness.

[0111] The thickness can also be understood as the height of the at least one cooling structure layer. A plurality of cooling structure layers together can form the thickness of a three-dimensional cooling structure.

[0112] The at least one cooling structure layer may comprise at least one three-dimensional cooling structure which may at least partially comprise at least one cooling channel.

[0113] The at least one cooling channel may have a colling channel height corresponding to the thickness of the total number of the cooling structure layers, in particular to the thickness of the plurality of the layers being deposited in a manufacturing process to form the cooling structure layer.

[0114] Alternatively or in addition, the cooling channel heigh may be between 0.1 mm and 4 mm, or between 0.2 mm and 3.5 mm, or between 0.3 mm and 3 mm, or between 0.4 mm and 2.5 mm, or between 0.5 mm and 2 mm, or between 0.6 mm and 1.8 mm. The cooling channel height may be at least 0.1 mm, or at least 0.2 mm, or at least 0.3 mm, or at least 0.4 mm, or at least 0.5 mm, or at least 0.6 mm. The cooling channel height may be at most 4 mm, or at most 3.5 mm, or at most 3 mm, or at most 2.5 mm, or at most 2 mm, or at most 1.8 mm.

[0115] According to an embodiment, the base plate and / or the cover layer and / or the intermediate base plates can each have a thickness between 10 pm and 2 mm, or between 20 pm and 1.5 mm, or between 40 pm and 1.2 mm, or between 50 pm and 1.0 mm. The base plate and / or the cover layer and / or the intermediate base plates can each have a thickness of 10 pm or more, or 20 pm or more, or 40 pm or more, or 50 pm or more. The base plate and / or the cover layer and / or the intermediate base plates can each have a thickness of 2 mm or less, or 1.5 mm or less, or 1.2 mm or less, or 1.0 mm or less.

[0116] The complete coldplate can have a thickness between 100 pm and 10 mm, or between 200 pm

[0117] August 28, 2025 13 / 44 CR0006P-WQ and 8 mm, or between 400 pm and 7 mm, or between 500 pm and 5 mm, or 700 pm and 3 mm. The complete coldplate can have a thickness of 100 pm or more, or 200 pm or more, or 400 pm or more, or 500 pm or more, or 700 pm or more. The complete coldplate can have a thickness of 10 mm or less, or 8 mm or less, or 7 mm or less, or 5 mm or less, or 3 mm or less.

[0118] The complete coldplate can have a cross-sectional surface area between 25 mm2and 10,000 mm2, or 50 mm2and 5,000 mm2, or 100 mm2and 3,000 mm2. The complete coldplate can have a cross-sectional surface area of 25 mm2or more, or 50 mm2or more, or 100 mm2or more. The complete coldplate can have a cross-sectional surface area of 10,000 mm2or less, or 5,000 mm2or less, or 3,000 mm2or less.

[0119] These values can ensure a suitable balance between an efficient cooling of semiconductor applications and a small size of the elements of the coldplate and therefore the coldplate itself.

[0120] According to an embodiment, the first cooling structure has a surface roughness Ra between 0.2 pm and 3.0 pm, or between 0.4 pm and 2.5 pm, or between 0.7 pm and 2.0 pm. The first cooling structure can have a surface roughness Ra of 0.2 pm or more, or 0.4 pm or more, or 0.7 pm or more. The first cooling structure can have a surface roughness Ra of 3.0 pm or less, or 2.5 pm or less, or 2.0 pm or less.

[0121] Additionally or alternatively, the first cooling structure can have a surface roughness Ra between 0.2 pm and 5.0 pm, or between 0.4 pm and 4.25 pm, or between 0.7 pm and 3.5 pm. The first cooling structure can have a surface roughness Ra of 0.2 pm or more, or 0.4 pm or more, or 0.7 pm or more. The first cooling structure can have a surface roughness Ra of 5.0 pm or less, or 4.25 pm or less, or 3.5 pm or less.

[0122] These surface roughness values Ra of the first cooling structure can also apply to each further cooling structure, the base plate, intermediate base plates and / or cover layer. It can be achievable by 3D screen printing.

[0123] The surface roughness can be understood as the arithmetic average of profile height deviations from the mean line.

[0124] The above-mentioned values regarding the surface roughness can refer to a surface roughness after the curing step and before any possible (maybe optional) further post-processing step.

[0125] In an embodiment, at least two, at least three, at least four or more than four coldplates can be manufactured simultaneously within one process.

[0126] This can increase overall manufacturing performance to enhance the efficiency of manufacturing the coldplates and can thus be more cost efficient.

[0127] August 28, 2025 14 / 44 CR0006P-WQ

[0128] Additionally or alternatively, at least the first three-dimensional cooling structure that is formed within the coldplate comprises a plurality of gaps having a longitudinal extension. The 3D screen printing can be performed in the direction of the longitudinal extension of the plurality of gaps. In other words, the material can be applied substantially in the direction of the longitudinal extension of the gaps, not transversely to the longitudinal extension. By this, three-dimensional features with a uniform height are achievable, in particular for small structures, and accuracy of the printing can be increased.

[0129] In an embodiment, in a transition region between the base plate and the cooling structure, and / or in a transition region between the cooling structure and the cover layer, at least one step is formed for providing a stepped, graduated or semi-continuous transition between the base plate and the cooling structure layer. Such a configuration can increase stability of the overall structure and can enable higher aspect ratios.

[0130] In an embodiment, the 3D screen printing comprises applying a paste having a particle size distribution of: d10 = between 5.0 pm and 8.0 pm, or 5.5 pm to 7.5 pm, or 6.0 pm to 7.0 pm, d50 = between 9.0 pm and 12.0, or 9.5 pm and 11.5 pm, or 10.0 pm and 11.0 pm, d90 = between 15.0 pm and 18.0 pm, or 15.5 pm and 17.5 pm, or 16.0 pm and 17.0 pm, wherein the paste can comprise spherical particles. Respective particle size distribution allows advantageous flowability of the paste in view of the structures to be formed therewith. Respective particle size distribution reduces or prevents leaks in the cooling structure.

[0131] In an embodiment, the 3D screen printing comprises applying a paste having a particle size distribution of: d10 = between 2.5 pm and 5.0 pm, or 3 pm to 5.0 pm, or 3.5 pm to 4.5 pm, d50 = between 5 pm and 11 , or 6 pm and 10 pm, or 7.0 pm and 9 pm, d90 = between 10 pm and 16 pm, or 11 pm and 15 pm, or 12 pm and 14 pm, wherein the paste can comprise spherical particles. Respective particle size distribution can contribute to advantageous flowability of the paste in view of the structures to be formed therewith. Respective particle size distribution can contribute to reducing or preventing leaks in the cooling structure.

[0132] August 28, 2025 15 / 44 CR0006P-WQ

[0133] In an embodiment, the 3D screen printing comprises applying a paste with particles, wherein a ratio R between an average particle diameter davg and the critical dimensions CD of the three- dimensional cooling structure is between 0.02 and 0.8, or between 0.04 and 0.6, or between 0.05 and 0.5. The ratio R between an average particle diameter davg and the critical dimensions CD of the three-dimensional cooling structure can be 0.02 or more, or 0.04 or more, or 0.05 or more. The ratio R between an average particle diameter davg and the critical dimensions CD of the three-dimensional cooling structure can be 0.8 or less, or 0.6 or less, or 0.5 or less. This ratio R can advantageously contribute to forming complex three-dimensional structures with the specified critical dimensions and aspect ratio.

[0134] An aspect of the disclosure relates to a coldplate for semiconductor cooling applications.

[0135] The features, advantages, effects and embodiments explained with regard to the process apply respectively to the coldplate and vice versa.

[0136] The coldplate comprises a base plate, and a first three-dimensional cooling structure disposed on top of the base plate, the first three- dimensional cooling structure having critical dimensions between 25 and 200 pm and an aspect ratio between 1 and 80, wherein the first three-dimensional cooling structure comprises at least one area with a microstructure including a network of channels for guiding a cooling agent, and two or more three-dimensional features which contribute to the formation of boundaries of the channels of the network of channels wherein the first three-dimensional cooling structure comprises at least one 3D screen printed cooling structure layer.

[0137] In an aspect, the disclosure relates to a coldplate for semiconductor cooling applications comprising:

[0138] - a 3D screen printed component, that comprises at least one base layer and one channel structure layer which together constitute a core of the coldplate, the core being preferably made of copper,

[0139] - a manifold connected to the core, such as by diffusion bonding, brazing, a gasket, and / or adhesive, the manifold being preferably made of copper, wherein the the manifold is fluidically coupled to the core to provide at least one path for cooling

[0140] August 28, 2025 16 / 44 agent that can enter, and one path for cooling agent that can leave the core, wherein optionally at least one inlet and / or one outlet connector is attached to manifold, such that the manifold and core combined create a closed path for fluid between the inlet and outlet connector.

[0141] The following embodiments refer to each aspect.

[0142] In an embodiment, the base plate and the first three-dimensional cooling structure can be 3D screen printed.

[0143] In an embodiment, a manifold can be attached to the base plate and / or the three-dimensional cooling structure, such as by diffusion bonding, brazing, a gasket, or / or adhesive.

[0144] In an embodiment, the manifold can be fluidically coupled to the base plate and / or the three- dimensional cooling structure to provide at least one path for the cooling agent that enters, and one path for the cooling that leaves the three-dimensional cooling structure.

[0145] In an embodiment, at least one inlet and / or one outlet connector can be attached to the manifold, such that the manifold and the base plate and / or the three-dimensional cooling structure combined create a closed path for cooling agent between the inlet and outlet connector.

[0146] According to an embodiment, the coldplate is at least partially or completely made of a material comprising impurities with oxygen and / or carbon. The impurities can comprise oxygen between 0.005 and 0.009 wt.%, or 0.006 and 0.008, and / or comprise carbon between 0.020 and 0.030 wt.%, or 0.024 and 0.026 wt.%

[0147] Additionally or alternatively, the coldplate can be at least partially or completely made of a material comprising impurities with oxygen and / or carbon. The impurities can comprise oxygen between 0.001 wt.% and 0.050 wt.%, or between 0.003 wt.% and 0.040 wt.%, or between 0.005 wt.% and 0.030 wt.%, and / or carbon between 0.001 wt.% and 0.050 wt.%, or between 0.003 wt.% and 0.040 wt.%, 0.005 wt.% and 0.025 wt.% and / or nitrogen between 0.00005 wt.% and 0.007 wt.%, or between 0.00008 wt.% and 0.006 wt.%, or between 0.0001 wt.% and 0.005 wt.%. A minimum amount of oxygen may be 0.001 wt.%, or 0.003 wt.%, or 0.005 wt.%. A maximum amount of oxygen may be 0.050 wt.%, or 0.040 wt.%, or 0.030 wt.%. A minimum amount of carbon may be 0.001 wt.%, or 0.003 wt.%, or 0.005 wt.%. A maximum amount of carbon may be 0.050 wt.%, or 0.040 wt.%, or 0.025 wt.%. A minimum amount of nitrogen may be 0.00005 wt.%, or 0.00008 wt.%, or 0.0001 wt.%. A maximum amount of nitrogen may be 0.007 wt.%, or 0.006 wt.% or 0.005 wt.%.

[0148] August 28, 2025 17 / 44 In an embodiment, the material of the at least first three-dimensional cooling structure, or the complete coldplate, has a relative density of at least 95%, preferably at least 97%, more preferably at least 99%.

[0149] According to an embodiment, the at least first three-dimensional cooling structure, or the complete coldplate, comprises or is made of copper.

[0150] The coldplate can be a metal coldplate. The coldplate can be a copper coldplate.

[0151] According to an embodiment, the base plate and / or the cover layer is a separate part. The base plate and / or the cover layer can be bonded to the at least one cooling structure layer, by brazing or copper-copper diffusion bonding.

[0152] In an embodiment, the base plate comprises at least one inlet and / or at least one outlet for guiding cooling agent to and / or from the cooling structure within the coldplate.

[0153] The cover layer can comprise at least one inlet, at least one outlet, and / or multiple orifices for guiding cooling agent to and / or from the cooling structure within the coldplate.

[0154] According to an embodiment, the coldplate can comprise a manifold structure within the coldplate, such as on top of the cover layer, for distributing cooling agent within the coldplate.

[0155] The coldplate can comprise a lid arrangement within the coldplate.

[0156] In one embodiment, the lid arrangement has at least one inlet and / or at least one outlet. The lid arrangement can have a first lid having at least one inlet and a second lid having at least one outlet. The lid arrangement can constitute an outer layer of the coldplate.

[0157] The channels of the network of channels can be interconnected.

[0158] The two or more three-dimensional features can comprise protrusions, regularly shaped fins, irregularly shaped fins, walls, pins and / or pillars.

[0159] In an embodiment, the at least one cooling structure layer has a thickness between 10 pm and 300 pm, or between 25 pm and 250 pm, or between 40 pm and 200 pm, or between 50 pm and 160 pm. The at least one cooling structure layer can have a thickness or 10 pm or more, or 25 pm or more, or 40 pm or more, or 50 pm or more. The at least one cooling structure layer can have a thickness of 300 pm or less, or 250 pm or less, or 200 pm or less, or 160 pm or less.

[0160] The base plate and / or the cover layer and / or the intermediate base plates can each have a thickness between 10 pm and 2 mm, or between 20 pm and 1.5 mm, or between 40 pm and 1.2 mm, or between 50 pm and 1.0 mm. The base plate and / or the cover layer and / or the intermediate base plates can each have a thickness of 10 pm or more, or 20 pm or more, or 40

[0161] August 28, 2025 18 / 44 m or more, or 50 pm or more. The base plate and / or the cover layer and / or the intermediate base plates can each have a thickness of 2 mm or less, or 1.5 mm or less, or 1.2 mm or less, or 1.0 mm or less.

[0162] According to a preferred example, the coldplate has a thickness between 100 pm and 10 mm, or between 200 pm and 8 mm, or between 400 pm and 7 mm, or between 500 pm and 5 mm, or 700 pm and 3 mm. The complete coldplate can have a thickness of 100 pm or more, or 200 pm or more, or 400 pm or more, or 500 pm or more, or 700 pm or more. The complete coldplate can have a thickness of 10 mm or less, or 8 mm or less, or 7 mm or less, or 5 mm or less, or 3 mm or less..

[0163] The complete coldplate can have a cross-sectional surface area between 25 mm2and 10,000 mm2, or 50 mm2and 5,000 mm2, or 100 mm2and 3,000 mm2. The complete coldplate can have a cross-sectional surface area of 25 mm2or more, or 50 mm2or more, or 100 mm2or more. The complete coldplate can have a cross-sectional surface area of 10,000 mm2or less, or 5,000 mm2or less, or 3,000 mm2or less.

[0164] In an embodiment, the first cooling structure has a surface roughness Ra between 0.2 and 3.0 pm, or between 0.4 pm and 2.5 pm, or between 0.7 pm and 2.0 pm. The first cooling structure can have a surface roughness Ra of 0.2 pm or more, or 0.4 pm or more, or 0.7 pm or more. The first cooling structure can have a surface roughness Ra of 3.0 pm or less, or 2.5 pm or less, or 2.0 pm or less.

[0165] In an embodiment, the first cooling structure can have a surface roughness Ra between 0.2 pm and 5.0 pm, or between 0.4 pm and 4.25 pm, or between 0.7 pm and 3.5 pm. The first cooling structure can have a surface roughness Ra of 0.2 pm or more, or 0.4 pm or more, or 0.7 pm or more. The first cooling structure can have a surface roughness Ra of 5.0 pm or less, or 4.25 pm or less, or 3.5 pm or less.

[0166] According to another embodiment, at least the first three-dimensional cooling structure that is formed within the coldplate comprises a plurality of gaps having a longitudinal extension.

[0167] In a transition region between the base plate and the cooling structure, and / or in a transition region between the cooling structure and the cover layer, a stepped, graduated or semi- continuous transition between the base plate and the cooling structure layer can be formed.

[0168] In an embodiment, the coldplate comprises a lid arrangement.

[0169] In an embodiment, the lid arrangement comprises at least one inlet and / or at least one outlet- The lid arrangement can have a first lid having at least one inlet and a second lid having at least one outlet. The lid arrangement can be provided as an outer top layer of the coldplate.

[0170] August 28, 2025 19 / 44 Further, the lid arrangement can contribute to covering the first three-dimensional cooling structure. Optionally, the first lid may correspond to the cover layer. Optionally, the second lid may correspond to a most outer layer of the coldplate of other embodiments, wherein the most outer layer is configured to be arranged farthest away from the semiconductor arrangement, wherein in other embodiments, the most outer layer may be described as a lid arrangement.

[0171] In an embodiment, the first three-dimensional cooling structure is arranged between the lid arrangement and the base plate. In other words, the first three-dimensional cooling structure is sandwiched between the base plate and the lid arrangement.

[0172] In an embodiment, the lid arrangement at least partly supports the first three-dimensional cooling structure. Accordingly, the first three-dimensional cooling structure is supported by the base plate and the lid arrangement. This can contribute to providing a rigid cooling plate, wherein the base plate is coupled to the lid arrangement via the first three-dimensional cooling structure. Accordingly, a cooling agent with high pressure can be provided to the cooling plate.

[0173] In an embodiment, the first three-dimensional cooling structure has an aspect ratio of between 6 and 70, or between 7 and 65, or between 8 and 60, or between 9 and 50, or between 10 and 40. A minimal aspect ratio can be 6, or 7, or 8 or 9, or 10. A maximal aspect ratio can be 70, or 65, or 60, or 50, or 40. Such aspect ratios can in some cases cause the first three-dimensional cooling structure to deform during a sintering process. The lid arrangement, however, being coupled to the first three-dimensional cooling structure opposite to the base plate, can contribute to preventing deformation of the first three- dimensional cooling structures by supporting the first three-dimensional cooling structure in a section opposite to the base plate. Accordingly, the lid arrangement can contribute to facilitating manufacturing high aspect ratios of between 6 and 70, or between 7 and 65, or between 8 and 60, or between 9 and 50.

[0174] In an embodiment, the lid arrangement comprises at least one surface for bonding with the manifold. The surface for bonding can be configured to be coupled with the manifold. This can contribute to facilitating connecting the manifold to the lid arrangement.

[0175] In an embodiment, the lid arrangement comprises a thermal contact surface. The thermal contact surface provides another option to dissipate heat to or from a heat source. Accordingly, further options are provided, which can contribute to increasing heat dissipation.

[0176] In an embodiment, the coldplate may comprise a base plate, a cooling structure layer, a cover layer, a manifold structure and a lid arrangement. Optionally, the base plate, the cooling structure layer, the cover layer, the manifold structure and the lid arrangement are arranged in this order.

[0177] August 28, 2025 20 / 44 In an embodiment, the base plate is configured to be connected to a semiconductor arrangement, such that thermal energy can be transferred from the semiconductor arrangement to the coldplate.

[0178] In an embodiment, the cooling structure layer comprises a three-dimensional cooling structure. The three-dimensional cooling structure may comprise cooling structure channels. The cooling structure channels may be in fluidic communication with the inlet being arranged on the lid arrangement. Further, the cooling structure channels may be in fluidic communication with the outlet.

[0179] In an embodiment, the cooling structure layer is arranged between the base plate and the cover layer. The cover layer may comprise at least one inlet orifice and at least one outlet orifice, which are configured to conduct cooling agent to and discharge cooling agent from cooling structure layer.

[0180] In an embodiment, the cover layer may comprise at least one unsupported cover layer overhang or protrusion, wherein the unsupported cover layer overhang or protrusion extends between 0.2 mm and 1.8 mm, or between 0.3 mm and 1.5 mm, or between 0.5 mm and 1.2 mm, or between 0.7 mm and 1.1 mm, or between 0.5 mm and 0.7 mm. A minimum extension of the unsupported cover layer overhang or protrusion may be 0.2 mm, or 0.3 mm, or 0.5 mm or 0.7 mm. A maximum extension of the unsupported cover layer overhang or protrusion may be 1.8 mm, or 1.5 mm, or 1.2 mm or 1.1 mm. The unsupported cover layer overhang or protrusion relates to a portion of the cover layer which extends beyond an underlying layer beneath, e.g., the cooling structure layer and / or the cover layer. The extent relates to a distance the unsupported cover layer overhang or protrusion extends beyond the layer beneath.

[0181] In an embodiment, the at least one cover layer orifice may comprise a cover layer orifice width being between 0.1 and 5, or between 0.15 and 4, or between 0.2 and 3, or between 0.25 and 2.5 times a cooling structure layer thickness. The cover layer orifice width may be at least 0.1, or 0.15, or 0.2 or 0.25 times the cooling structure layer thickness. The cover layer orifice width may be at most 5, or 4, or 3 or 2.5 times the cooling structure layer thickness. A ratio of the cover layer orifice width and the cooling structure layer thickness may be determined based on at least one of the following: coolant agent, geometric characteristics, pressure, flow rate, etc.

[0182] In another embodiment, the cover layer orifice width is the same as the cooling structure layer thickness.

[0183] In an embodiment, an extent of the unsupported cover layer overhang may range between 0.1 and 100 times, or between 5 and 90 times, or 25 and 80 times or 40 and 75 times, or 50 and 70

[0184] August 28, 2025 21 / 44 times of a cover layer thickness. The minimum extent of the unsupported cover layer overhang may be 0.1, or 5, or 25, or 40, or 50 times of a cover layer thickness. The maximum extent of the unsupported cover layer overhang may be 100, or 90, or 80, or 75, or 70 times of a cover layer thickness. The cover layer thickness relates to a thickness of the cover layer. The unsupported overhang can be 0.2 mm to 1.0 mm, or 0.3 mm to 0.9 mm, or 0.4 mm to 0.8 mm, or 0.5 mm to 0.7 mm.

[0185] The unsupported overhang can be formed by a plurality of layers, for example 3 to 2000 layers, or 5 to 1500 layers, or 50 to 1250 layers, or 100 to 1000 layers. The unsupported overhang can be formed by at least 3 layers, or at least 5 layers, or at least 50 layers, or at least 100 layers. The unsupported overhang can be formed 2000 layers or less, or 1500 layers or less, or 1250 layers or less, or 1000 layers or less.

[0186] In an embodiment, the cover layer thickness may be between 0.01 and 10, or between 0.05 and 9, or between 0.1 and 8, or between 0.5 and 7, or between 0.75 and 6, or between 1 and 5 times the cover layer orifice width. A minimum cover layer thickness may be 0.01, or 0.05, or 0.1, or 0.5, or 0.75 or 1 times the cover layer orifice width. A maximum cover layer thickness may be 10, or 9, or 8, or 7, or 6 or 5 times the cover layer orifice width.

[0187] In an embodiment, the manifold structure may comprise a manifold structure thickness which is thicker than a cooling structure layer thickness. For example, the manifold structure thickness may be between 1.1 times and 5 times, or between 1.5 times and 4 times, or between 1.75 times and 3.5 times, or between 2 times and 3 times the cooling structure layer thickness. The manifold structure thickness may be at least 1.25, or 1.5, or 1.75 or 2 times the cooling structure layer thickness. The manifold structure thickness may be at most 5, or 4, or 3.5, or 3 times the cooling structure layer thickness. This may contribute to minimizing a pressure drop in the manifold structure

[0188] In an embodiment, the manifold structure may comprise a manifold structure wall having a manifold structure wall aspect ratio of between 1 and 20, or 1 and 18, or 1 and 15, or 1 and 13, or 1 and 11. The manifold structure wall aspect ratio may be at least 1. The manifold structure wall aspect ratio may be at most 20, or 18, or 15, or 13 or 11. Such manifold structure wall aspect ratios may contribute to achieving good mechanical stability.

[0189] In an embodiment, the at least one manifold structure channel may comprise a manifold structure channel width that may be at most 3 times, or at most 2 times, or at most 1.75 times the extent of the unsupported overhang or protrusion, at most 1.5 times, at most 1.25 times the extent of the unsupported cover layer overhang or protrusion. Alternatively or in addition, the manifold structure channel width may be between 0.2 mm and 3.6 mm, or between 0.3 mm and 3 mm, or between 0.5 mm and 2.5 mm, or between 0.7 mm and 2.2 mm. A minimum extension

[0190] August 28, 2025 22 / 44 of the manifold structure channel width may be 0.2 mm, or 0.3 mm, or 0.5 mm or 0.7 mm. A maximum of the manifold structure channel width may be 3.6 mm, or 3 mm, or 2.5 mm or 2.2 mm.

[0191] Additionally or alternatively, the manifold structure channel width may be between 0.2 mm and 1.8 mm, or between 0.3 mm and 1.5 mm, or between 0.5 mm and 1.2 mm, or between 0.7 mm and 1.1 mm. A minimum manifold structure channel width may be at least 0.2 mm, or at least 0.3 mm, or at least 0.5 mm or at least 0.7 mm. A maximum manifold structure channel width may be at most 1.8 mm, or at most 1.5 mm, or at most 1.2 mm or at most 1.1 mm. This may contribute to providing a sufficient mechanical stability.

[0192] In an embodiment, the manifold structure may comprise at least one support structure being configured to support the overhang or protrusion of the cover layer. The unsupported overhang or protrusion may be at least partly in direct proximity of the supported overhang or protrusion. The at least one support structure may contribute to extending the overhang or protrusion of the cover layer and to extending the manifold structure channel width accordingly.

[0193] In an embodiment, the lid arrangement may comprise a lid arrangement thickness which is between 0.1 and 20, or between 0.2 and 18, or between 0.3 and 15, or between 0.5 and 14 times an unsupported lid arrangement overhang of the lid arrangement. The lid arrangement thickness may be at least 0.1, or 0.2, or 0.3, or 0.5 times the unsupported lid arrangement overhang or protrusion. The lid arrangement thickness may be at most 20, or 18, or 15 or 14 times the unsupported lid arrangement overhang or protrusion. The unsupported lid arrangement overhang or protrusion relates to a portion of the lid arrangement that protrudes beyond at least one manifold structure wall. This may contribute to providing a sufficient mechanical stability.

[0194] Alternatively or in addition, the lid arrangement thickness may be between 0.1 and 4, or between 0.2 and 3.5, or between 0.3 and 3, or between 0.4 and 2.75, or between 0.5 and 2.5 times the manifold structure channel width. The lid arrangement thickness may be at lest 0.1, or at least 0.2, or at least 0.3, or at least 0.4, or at least 0.5 times the manifold structure channel width. The lid arrangement thickness may be at most 4, or at most 3.5, or at most 3, or at most 2.75, or at most 2.5 times the manifold structure channel width.

[0195] In an embodiment, the at least one lid arrangement orifice has a lid arrangement orifice width and a lid arrangement orifice length, wherein the lid arrangement orifice width is between is between 0.1 and 5, or between 0.15 and 4, or between 0.2 and 3, or between 0.25 and 2.5 times the lid arrangement orifice length. The lid arrangement orifice width may be at least 0.1, or 0.2 or 0.25 times the lid arrangement orifice length. The lid arrangement orifice width may be at most 5, or 4, or 3 or 2.5 times the lid arrangement orifice length.

[0196] August 28, 2025 23 / 44 In an embodiment, the distance between two lid arrangement orifices may be at least 1 , or 2, or 3, or 4 or 6 times the cover layer thickness. Alternatively or in addition, the distance may be at least 0.25 mm, or 0.5 mm, 0.75 mm or 1 mm.

[0197] In an embodiment, the coldplate may comprise at least two lid arrangement orifices, wherein a distance between two lid arrangement orifices is between 1 and 1 ,000 times, or between 2 and 500 times, or between 3 and 100 times, or between 4 and 75 times, or between 5 and 40 times the cover layer thickness. The distance may be at least 1 , or 2, or 3, or 4 or 6 times the cover layer thickness. The distance may be at most 1 ,000 or 500, or 100, or 75 or 40 times the cover layer thickness. For example, if the colling structure layer thickness is between 0.4 mm and 0.6 mm, the lid arrangement orifice width is between 0.1 mm and 1.5 mm, the manifold structure thickness is between 0.8 mm and 1.8 mm, the manifold structure channel width is between 0.5 mm and 1 mm, and the manifold structure wall thickness is between 0.08 mm and 0.2 mm, the distance between two lid arrangement orifices may be about 1 mm.

[0198] In an embodiment, the coldplate having at least two lid arrangement orifices, wherein a distance between two of the at least two lid arrangement orifices is between 0.25 mm and 50 mm, or between 0.5 mm and 40 mm, or between 0.75 mm and 30 mm, or between 1 mm and 20 mm. The distance may be at least 0.25 mm, or 0.5 mm, 0.75 mm or 1 mm. The distance may be at most 50 mm, or 40 mm, or 30 mm, or 20 mm.

[0199] In one embodiment, at least one of the cover layer orifice and the lid arrangement orifice comprise a slit. The slit may have two extensions being arranged in a plane that are perpendicular to the thickness of the corresponding cover layer or lid arrangement, wherein one of the extensions is greater than the other extension. For example, one extension is at least 2 times, or at least 5 times, or at least 10 times, or at least 20 times, or at least 50, or at least 100 times greater than the other one.

[0200] In an embodiment, the coldplate comprises six, seven, eight, nine, ten, eleven, twelve or more layers. For example, the three-dimensional cooling structure may be formed of several layers, and / or the coldplate may comprise several cover layers and / or several manifold structures.

[0201] Brief Description of the Drawings

[0202] Exemplary embodiments of the invention will be discussed in the following with reference to the attached schematic figures. Same features may be assigned same reference signs throughout the figures.

[0203] Figure 1 shows a block diagram of the process of manufacturing a coldplate for semiconductor cooling applications according to an embodiment of the

[0204] August 28, 2025 24 / 44 invention. Figure 2 shows a coldplate according to one embodiment during the various manufacturing steps of the process according to the invention. Figures 3a-c each show a coldplate for semiconductor cooling applications according to a first embodiment of the invention and indicate various configuration steps of manufacturing the coldplate. Figures 4a-c each show a coldplate for semiconductor cooling applications according to a further embodiment of the invention and indicate show various configuration steps of manufacturing the coldplate. Figures 5a-c show cooling structures of a coldplate for semiconductor cooling applications according to various embodiments of the invention. Figures 6a-b show a cover layer of a coldplate for semiconductor cooling applications according to an embodiment of the invention from above (Figure 6a) and in a cross-sectional side view (Figure 6b). Figures 7a-b show a cover layer of a coldplate for semiconductor cooling applications according to an embodiment of the invention from above (Figure 7a) and in a cross-sectional side view (Figure 7b). Figures 8a-c show a coldplate for semiconductor cooling applications according to an embodiment of the invention in an assembled state (without a lid arrangement) from above (Figure 8a), a lid arrangement of such a coldplate from above (Figure 8b) and the coldplate in a cross-sectional side view (Figure 8c). Figure 9 shows a coldplate for semiconductor cooling applications according to a further embodiment of the invention in an assembled state from above. Figures 10a-b each show a top view of a lid arrangement of a coldplate for semiconductor cooling applications according to a first (Figure 9a) and second (Figure 9b) embodiment of the invention. Figures 11a-b each show a cross-sectional side view of a coldplate for semiconductor cooling applications according to an embodiment (Figure 10a) and another embodiment (10b) in a fully state comprising connector arrangements. Fig. 12 shows a cold plate for semiconductor cooling applications according to an embodiment of the invention in an assembled state.

[0205] August 28, 2025 25 / 44 Fig. 13 shows a schematic view of a cold plate for semiconductor cooling applications according to the embodiment of Fig. 12 of the invention in an assembled state.

[0206] Fig. 14 shows a detailed view of Fig. 13.

[0207] Detailed Description of the Disclosure

[0208] Figure 1 shows a block diagram indicating the steps of a process of manufacturing a coldplate 100 for semiconductor cooling applications.

[0209] The first step 1000 includes providing a base plate 102.

[0210] The second step 2000 includes a 3D screen printing of at least one cooling structure layer 104 directly or indirectly on top of the base plate 102 with a build rate, including depositing and curing the at least one cooling structure layer, of 2,000 cm3per hour to form a first three- dimensional cooling structure 106 within the coldplate having critical dimensions of 60 pm and an aspect ratio of 50. Of course, other examples within the above specified ranges are possible.

[0211] The formed first three-dimensional cooling structure 106 comprises at least one area 108 with a microstructure including a network of channels 110 for guiding a cooling agent, and two or more three-dimensional features 112 which contribute to the formation of boundaries of the channels of the network of channels 110.

[0212] In this example, in the first step 1000, also the base plate 102 is manufactured by 3D screen printing which improves bonding between the base plate and the cooling structure and thus stability of the coldplate.

[0213] In a third step 3000 of the process a cover layer 114 is provided on top of the first three- dimensional cooling structure 106 to directly cover the cooling structure 106.

[0214] A curing step, not shown, can be performed after all layers have been 3D screen printed.

[0215] The curing is performed by sintering, thermal curing, UV curing, electron beam curing, chemical curing, microwave curing, induction curing, room temperature curing, or a combination thereof. After curing, the material of which the coldplate is formed has a relative density of more than 97%.

[0216] The at least one cooling structure layer 104 is 3D screen printed to have a thickness or in other words height of 60pm.

[0217] The coldplate provided in this example has a thickness of 3 mm.

[0218] With view to Figure 2, the aforementioned process is shown and will be explained in more detail

[0219] August 28, 2025 26 / 44 by an example of manufacturing parts of a coldplate 100 according to one embodiment of the invention. Namely, step 1000 of Figure 1 is shown in parts (II) to (IV) of Figure 2 and step 2000 of Figure 1 is shown in parts (V) and (VI).

[0220] As shown in step (I) of Figure 2, a support plate 101 is provided on which the 3D screen printing can be performed.

[0221] As can be seen in part (II) of Figure 2 a stencil 103 is arranged on top of the support plate 101, to also mark the regions in which the base plate 102 will be applied. The stencil 103 is used as a frame for the paste to be applied to form the base plate 102. According to the shown embodiment, the stencil 103 comprises four spaces 105 in which a base plate 102 is formed, respectively. In other words, in this embodiment, four base plates 102 can be printed on top of the support layer 101.

[0222] At part (III) the paste is deposited on the support plate 101 for printing the base plates 102.

[0223] To deposit the base plates 102 paste, here a copper paste, is applied to one side of the support plate 101 and drawn over the stencil 103 using a scraper 107. The paste thereby fills the spaces 105 of the stencil 103 to form the base plates 102.

[0224] After depositing the paste the stencil 103 will be removed so that only the four printed base plates 102 remain on top of the support plate 101 as can be seen in part (IV) of Figure 2.

[0225] Subsequently, as shown in part (V) of Figure 2 a cooling structure layer 104 including a three- dimensional cooling structure 106 is formed on top of each base plate. The printing of the cooling structure layer 104 as well as the three-dimensional cooling structure 106 is performed similarly to the application of the base plate 102 as described above, namely with the help of a further stencil 103. The height of the stencil 103 corresponds to the height of the cooling structure layers 104, so that the preferred dimensions of the cooling structure layer 104 mentioned above can be achieved.

[0226] In part (VI) of Figure 2, the partially formed coldplate 100 is shown which comprises base plate 102 and a cooling structure layer 104 applied on top of the base plate 102. More precisely, four such partially formed coldplates 100 are shown.

[0227] Additionally, a not shown cover layer 114 and / or a lid arrangement 116 and / or further cooling structures and intermediate layers can be applied on top of the cooling structure layer 104 similarly by 3D screen printing. Alternatively, the cover layer 114 and / or the lid arrangement 116 can be applied as separate parts on top of the cooling structure layer 104. For example, the cover layer 114 and / or the lid arrangement 116 then can be arranged and bonded on top of the cooling structure layer 104.

[0228] August 28, 2025 27 / 44 After the part (VI), the support plate 101 will be removed from the base plate 102 as the support plate 101 is only provided for manufacturing but does not form part of the coldplate 100.

[0229] With reference to Figure 3a-c, a sideview of a coldplate 100 for semiconductor cooling applications is shown in different manufacturing steps.

[0230] Figure 3(a) shows the base plate 102. At least one cooling structure layer 104, in the embodiment of Figure 3 exactly one cooling structure layer 104, is applied on top of the base plate 102 by 3D screen printing (Figure 3(b)). As can be seen in Figure 3(b), the cooling structure layer 104 comprises a three-dimensional cooling structure 106 for heat transfer from a semiconductor device to which the coldplate is to be attached during operation. The three- dimensional cooling structure 106 - as shown in Figure 3(b) is therefore a part of the cooling structure layer 104. Alternatively, the three-dimensional cooling structure 106 can be the cooling structure layer 104. In other words, the whole cooling structure layer 104 then comprises and more precisely is formed by the three-dimensional cooling structure 106.

[0231] The three-dimensional cooling structure 106 comprises an area 108 with two or more three- dimensional features 112 for enabling the heat transfer. The three-dimensional features 112 will be explained in more detail with reference to Figure 5.

[0232] At the next step (Figure 3(c)), a cover layer 114 is applied on top of the cooling structure layer 104. In the example of Figure 3, the cover layer 114 serves as a lid arrangement 116.

[0233] The embodiment according to Figure 3 shows the simplest embodiment according to the invention and is manufactured by the process according to the explanations of Figure 1 and / or Figure 2.

[0234] Referring to Figure 4, a further embodiment of a coldplate 100 for semiconductor cooling applications is shown that has been manufactured based on the process as mentioned with regard to Figure 1 and / or Figure 2.

[0235] The overall arrangement of the components is similar to the one described in view of Figure 3. However, there are some slight differences. A support plate 101 is provided on which two base plates 102.1, 102.2 are formed. The base plates 102.1 , 102.2 are, here, 3D screen printed on the surface of the support plate 101 , but - as described with reference to Figure 2 - are later removed therefrom as the support plate 101 is only provided for manufacturing, but does not form part of the coldplate. Hence, Figure 4 indicates parallel or simultaneous manufacturing of more than one coldplate 100 as also shown in Figure 2.

[0236] On top of each base plates 102.1 , 102.2 a cooling structure layer 104 is provided by 3D screen printing (see Figure 4(b)). Additionally, more than one cooling structure layer 104 can be

[0237] August 28, 2025 28 / 44 provided on top of each sub-baseplate 102.1, 102.2 (not shown). The number of cooling structure layers 104 on top of each base plate 102.1 , 102.2 can vary depending on the intended semiconductor application for which the coldplate is manufactured. For ease of understanding, only one cooling structure layer 104 is shown on top of each base plates 102.1 , 102.2. The cooling structure layers 104 each comprise a three-dimensional cooling structure 106, area 108 and three-dimensional features 112.

[0238] According to Figure 4(c), a cover layer 114 is applied by 3D screen printing on top of each cooling structure layer 104. As already mentioned regarding the embodiment shown in Figure 3, the cover layer 114 also in this embodiment serves the purpose of a lid arrangement 116.

[0239] The design shown in Figure 4a-c corresponds to the design in Figure 3a-c in terms of structure and function, so that reference is made in this respect to the explanations to Figure 3a-c.

[0240] Figure 5 shows cooling structure layers 104 of a coldplate 100 for semiconductor cooling applications according to various embodiments.

[0241] With reference to Figure 5(a) an embodiment of the cooling structure layer 104 is shown. The cooling structure layer 104 3D screen printed on top of the base plate 102 comprises a three- dimensional cooling structure 106. In more detail, the main area of the cooling structure layer 104 comprises the three-dimensional cooling structure 106.

[0242] Further, the three-dimensional cooling structure 106 comprises an area 108 with a plurality of three-dimensional features 112. The area 108 is graphically indicated by the dashed line. The three-dimensional features 112 are fins forming boundaries of an irregular network of channels 110 specifically designed for an intended application.

[0243] In Figure 5(b), the cooling structure layer 104 3D screen printed on top of the base plate 102 comprises a three-dimensional cooling structure 106. In more detail, the main area of the cooling structure layer 104 comprises the three-dimensional cooling structure 106.

[0244] Further, the three-dimensional cooling structure 106 comprises an area 108 with a plurality of three-dimensional features 112. The area 108 is graphically indicated by the dashed line. The three-dimensional features 112 are configured as slits forming a network of channels 110 as can be seen in Figure 4(b).

[0245] Figure 5(c) shows another embodiment of the cooling structure layer 104. In this embodiment, the cooling structure layer 104 is also applied on top of the base plate 102 by 3D screen printing and comprises a three-dimensional cooling structure 106.

[0246] As can be seen from Figure 5(c), the three-dimensional cooling structure 106 also comprises an

[0247] August 28, 2025 29 / 44 area 108 with a plurality of three-dimensional features 112. Therefore, the general arrangement is similar to the already explained other embodiments of the cooling structure layer 104, especially to the cooling structure layer 104 according to the embodiment as shown in Figure 5(b).

[0248] However, the difference between the embodiments according to Figure 5(b) and Figure 5(c) lies in the design of the three-dimensional features 112. The three-dimensional features 112 according to the embodiment of Figure 5(c) are configured as pins or protrusions that form a network of channels therebetween.

[0249] In addition, and regarding the other features of the coldplate 100, the design shown in Figures 5a-c corresponds to the design shown in Figures 3a-c to 4a-c in terms of structure and function, so that reference is made in this respect to the explanations on Figures 3a-c to 4a-c.

[0250] With respect to Figure 6a-b a cover layer 114 according to an embodiment is shown from above (Figure 6(a)) and in a cross-sectional side view (Figure 6(b)).

[0251] The cover layer 114 is provided by 3D screen printing. In other embodiments, the cover layer 114 can be provided as a separate part and can be bonded to the at least one cooling structure layer 104, for example by brazing or copper-copper diffusion bonding.

[0252] The cover layer 114 according to the embodiment as shown in Figure 6(a)-(b) is provided with multiple orifices 118 for guiding cooling agent to and / or from the cooling structures 104, 106, 112 within the coldplate 100. The embodiment according to Figure 6(a)-(b) shows six orifices 118. However, the number of orifices 118 of the cover plate 114 is not limited to this. Moreover, the cover plate 114 can comprise any other number of orifices 118, like e.g. 2 to 10, preferably 5 to 15 or more preferably 10 to 30 or more. The number of orifices 118 can vary depending on the technical needs of the semiconductor device to be cooled, especially the heat that must be transferred.

[0253] Alternatively, in an embodiment, the cover layer 114 can comprise one inlet and at least one outlet for guiding cooling agent to and / or from the cooling structures 104, 106, 112 within the coldplate 100.

[0254] In addition, and regarding the other features of the coldplate 100, the design shown in Figures 6(a)-(b) corresponds to the design shown in Figures 3(a)-(c) to a-c in terms of structure and function, so that reference is made in this respect to the explanations to Figures 3(a)-(c) to 5(a)- (c).

[0255] With reference to Figure 7(a)-(b), another embodiment with the cover layer 114 and an additional lid 116 is shown from above (Figure 7(a)) and in a cross-sectional side view (Figure

[0256] August 28, 2025 30 / 44 7(b)). The cross-sectional side view according to Figure 7(b) corresponds to the view along the sectional line A shown in Figure 7(a). In the embodiment shown in Figures 7(a) and (b), a manifold structure 117 is provided on top of cover layer 114 for guiding cooling agent to and / or from the cooling structures 104, 106, 112 within the coldplate 100, via multiple orifices 118 within the cover layer 114. The manifold structure 117 can be an additional component or the lid can comprise the manifold structure. The manifold structure 117 has a manifold wall 124, and is configured as a Z-manifold structure, to guide the cooling agent from an inlet (not shown in Figures 7(a) and (b)) via the orifices 118 to an outlet (not shown in Figures 7(a) and (b)).

[0257] In detail, the flow of the cooling agent is as follows: The cooling agent flows from an inlet (not shown in Figures 7(a) and (b)) through an intake side of the manifold (on the left side of the graphical plane in Figure 7(a)) and will be guided by the manifold wall 124 to the orifices 118a-c. The cooling agent then flows through the orifices 118a-c into the three-dimensional cooling structure 106 (not shown in Figure 7(a)) and flows back through the orifices 118d-f to the right side of the manifold structure 117 (viewed with regard to the graphical plane of Figure 7(a)). After passing the orifices 118d-f, the cooling agent escapes through an outlet (not shown in Figures 7(a) and (b)). As can be seen from Figure 7(a) and in view of the above explanation, the manifold wall 124 serves as a boundary between the intake side and outlet side of the manifold in a way that the cooling agent is “forced” to flow through the orifices 118a-f and therefore through the cooling structure 106 thus cooling the semiconductor application in contact with the coldplate.

[0258] In addition, and regarding the other features of the coldplate 100, the design shown in Figures 7(a)-(b) corresponds to the design shown in Figures 3(a)-(c) to 6(a)-(b) in terms of structure and function, so that reference is made in this respect to the explanations to Figures 3(a)-(c) to 6(a)- (b).

[0259] Figure 8(a)-(c) each show a coldplate 100 for semiconductor cooling applications according to an embodiment of the invention in an assembled state from above (Figure 8(a)) and in a cross- sectional side view (Figure 8(c)). Additionally, Figure 8(b) shows a lid arrangement 116 from above comprising an inlet 120 and an outlet 122. The cross-sectional side view according to Figure 8(c) corresponds to the view along the sectional line A shown in Figure 8(a). Alternatively, the inlet 120 and the outlet 122 can be provided on the manifold structure 117. Alternatively, one of the inlet 120 and the outlet 122 can be provided on or in the lid arrangement 116 or manifold structure 117, while the other one is provided on or in the manifold structure 117 or the lid arrangement 116.

[0260] The lid 116 comprises an inlet 120 and an outlet 122 for guiding cooling agent to and / or from

[0261] August 28, 2025 31 / 44 the cooling structures 104, 106, 112 within the coldplate 100, via multiple orifices 118 within the cover layer 114. To this, the lid 116 is provided on top of a manifold structure 117. In alternative examples, the lid can comprise the manifold structure. The manifold structure 117 is similar to the manifold structure of Figures 7a and b. It has a manifold wall 124, and is configured as a Z- manifold structure, to guide the cooling agent from the inlet 120 via the orifices 118 to the outlet 122.

[0262] In detail, the flow of the cooling agent is as follows: The cooling agent flows from the inlet 120 (which can be connected to an connector - not shown) through an intake side of the manifold (on the left side of the graphical plane in Figure 7(a)) and will be guided by the manifold wall 124 to the orifices 118a-c. The cooling agent then flows through the orifices 118a-c into the three-dimensional cooling structure 106 (not shown in Figure 7(a)) and flows back through the orifices 118d-f to the right side of the manifold structure 117 (viewed with regard to the graphical plane of Figure 7(a)). After passing the orifices 118d-f, the cooling agent escapes through the outlet 122. After escaping the outlet 122, the cooling agent can for example flow through a connector (not shown). As can be seen from Figure 7(a) and in view of the above explanation, the manifold wall 124 serves as a boundary between the inlet 120 and the outlet 122 of the lid in a way that the cooling agent is “forced” to flow through the orifices 118a-f and therefore through the cooling structure 106 thus cooling the semiconductor application in contact with the coldplate.

[0263] All shown parts can be 3D screen printed.

[0264] In addition, and regarding the other features of the coldplate 100, the design shown in Figures 8(a)-(c) corresponds to the design shown in Figures 3(a)-(c) to 7(a)-(b) in terms of structure and function, so that reference is made in this respect to the explanations to Figures 3(a)-(c) to 7(a)- (b).

[0265] With reference to Figure 9, a coldplate 100 for semiconductor cooling applications according to a further embodiment of the invention is shown from above.

[0266] In general, the configuration of the coldplate 100 is similar to the configuration of the coldplate 100 as shown and explained with regard to Figures 8(a)-(c).

[0267] A difference between the embodiment shown in Figure 9 to the embodiment shown in Figures 8(a)-(c) is that the manifold structure 117 of the coldplate 100 is provided with enlarged intake and outlet pools 126 to increase the flow distribution of the cooling agent. The enlarged inlet / outlet pool 126 is graphically characterized by the vertical line (viewed in the drawing plane). Due to the geometric arrangement of the inlet / outlet pool 126 the flow distribution of the cooling agent can be increased compared to the embodiment according to Figures 8(a)-(c)

[0268] August 28, 2025 32 / 44 CR0006P-WQ without an inlet / outlet pool 126.

[0269] In addition, and regarding the other features of the coldplate 100, the design shown in Figure 9 corresponds to the design shown in Figures 3(a)-(c) to 8(a)-(c) in terms of structure and function, so that reference is made in this respect to the explanations to Figures 3(a)-(c) to 8(a)- (c).

[0270] A lid arrangement 116 of a coldplate 100 for semiconductor cooling applications according to a a further embodiment of the invention is shown in Figures 10a-b.

[0271] Figure 10(a) shows a first (bottom) part of the lid arrangement 116. Figure 10(b) shows a second (top) part of the lid arrangement 116. Both parts are shown from above. In an assembled state, only the second (top) part could be viewed from above.

[0272] The bottom part of the lid arrangement 116 shown in Figure 10(a) comprises a large intake area 128 that will be in fluidic connection with inlet 120 of the top part for guiding cooling agent via orifices 118d, 118e, 118f of the cover layer to the cooling structure (not shown). Further, the bottom part is provided with walls 129a, 129b, 129c forming channels for guiding cooling agent from the cooling structure via orifices 118a, 118b, 118c of the cover layer to outlets 122a, 122b, 122c of the top part.

[0273] Referring to Figures 11a-b, a cross-sectional view of a coldplate 100 for semiconductor cooling applications according to a first embodiment (Figure 11(a)) and a second embodiment (11(b)) in a fully assembled state comprising connector assemblies 130 is shown.

[0274] Figure 11(a) shows a cross-sectional view of a coldplate 100 according to a first embodiment. In this embodiment, the connector assembly 132 only comprises one connector, which can - depending on the technical and mechanical structure of the coldplate 100 and / or the device to be cooled - serve as an inlet connector 132 or an outlet connector 134, for distributing cooling agent to and / or from the three-dimensional cooling structure 106.

[0275] Preferably, the connector assembly 132 can be provided by 3D screen printing.

[0276] With regard to Figure 11(b), a second embodiment of the coldplate 100 with a different connector assembly 130 is shown.

[0277] According to this embodiment, the connector assembly 130 comprises two connectors, namely an inlet connector 132 and an outlet connector 134 for distributing cooling agent to and / or from the three-dimensional cooling structure 106.

[0278] In addition, and regarding the other features of the coldplate 100, the design shown in Figure 11(a)-(b) corresponds to the design shown in Figures 3(a)-(c) to 10(a)-(b) in terms of structure

[0279] August 28, 2025 33 / 44 and function, so that reference is made in this respect to the explanations to Figures 3(a)-(c) to 10(a)-(b).

[0280] Further, all the above-mentioned features of the embodiments can - if they are not declared as alternatives - combined with each other to further embodiments without leaving the scope of the present invention. For example, the coldplate 100 according to Figures 11(a)-(b) can also comprise a cover layer 114 according to the example as shown in Figure 7(a)-(b).

[0281] In the above described embodiments the first three-dimensional cooling structure 106 can be, at least partially, structurally coupled to the lid arrangement 116. In other words, the first three-dimensional cooling structure 106 can be sandwiched between the lid arrangement 116 and the base plate 102.

[0282] By providing the first three-dimensional cooling structure 106 between the lid arrangement 116 and the base plate 102, the first three-dimensional cooling structure 106, the lid arrangement 116 and the base plate 102 support each other, which can contribute to providing a sufficiently rigid coldplate 100. Therefore, high pressures of cooling agent can be provided to the coldplate 100, which can contribute to sufficient heat dissipation.

[0283] High aspect ratios, such as between 6 and 60, between 7 and 50, between 8 and 10 or between 9 and 30, of the first three-dimensional cooling structure 106 the lid arrangement 116 being structurally connected to the first three-dimensional cooling structure 106, can contribute to preventing deformation of the first three-dimensional cooling structure 106 during a sintering process. In particular, the first three-dimensional cooling structure 106 is structurally supported by the base plate 102 and the lid arrangement 116. This can contribute to facilitating a production process, as the first three-dimensional cooling structure 106 is supported by the lid arrangement 116 during production.

[0284] Further, the lid arrangement 116 may comprise a not depicted thermal contact surface, which allows heat dissipation to or from the cooling agent. Accordingly, another thermal contact surface is provided, which contributes to dissipating heat.

[0285] The lid arrangement 116 can be provided with a not depicted surface for bonding with the manifold structure 117. The surface helps to facilitate connecting the lid arrangement 116 to the manifold structure 117. Optionally, the surface can be adapted to match a design of the manifold structure 117.

[0286] Fig. 12 shows an embodiment of a coldplate 100 for semiconductor cooling applications. The coldplate 100 comprises a base plate 102, a cooling structure layer 104, a cover layer 114, a manifold structure 117 and a lid arrangement 116.

[0287] August 28, 2025 34 / 44 The base plate 102 supports the cooling structure layer 104 which may comprise at least one three-dimensional cooling structure (not depicted). The three-dimensional cooling structure may form at least one cooling channel, which is configured to conduct a cooling agent. The cooling agent may be introduced into and discharged from the cooling structure channels by means of the cover layer 114.

[0288] The cover layer 114 may comprise several orifices 118, wherein at least one of the orifices 118 may be an inlet orifice 118 and at least one of the orifices 118 may be an outlet orifice 118. The inlet orifice 118 and outlet orifice 118 are configured to introduce or discharge cooling agent into or from the at least one cooling structure.

[0289] The cover layer 114 may comprise at least one unsupported cover layer overhang or protrusion, which protrudes beyond the three-dimensional cooling structure. This unsupported cover layer overhang or protrusion may be arranged within the vicinity of the inlet orifice 118 and / or the outlet orifice 118. For example, the inlet orifice 118 and / or the outlet orifice 118 may be smaller than a portion of the cooling channel being arranged in the vicinity of the inlet orifice 118 and / or the outlet orifice 118.

[0290] The unsupported cover layer overhang or protrusion may comprise an extent, which may be between 0.2 mm and 1.8 mm, or between 0.3 mm and 1.5 mm, or between 0.5 mm and 1.2 mm, or between 0.7 mm and 1.1 mm. A minimum extension of the unsupported cover layer overhang may be 0.2 mm, or 0.3 mm, or 0.5 mm or 0.7 mm. A maximums extension of the unsupported cover layer overhang may be 1.8 mm, or 1.5 mm, or 1.2 mm or 1.1 mm.

[0291] Optionally, the unsupported cover layer overhang or protrusion may be in vicinity of a supported cover layer overhang protrusion, which is supported by a not depicted support structure. The support structure contributes to extending the overhang or protrusion compared to the unsupported cover layer overhang protrusion.

[0292] Further, the cover layer 114 may be arranged between the cooling structure layer 104 and the manifold structure 117.

[0293] The manifold structure 117 may comprise a manifold structure thickness, which may be thicker than the cooling structure layer 104 thickness. Alternatively, the manifold structure thickness may be same or smaller than the cooling structure layer 104 thickness.

[0294] Further, the manifold structure 117 may comprise at least one manifold structure channel 117a. Cooling agent being discharged from the cooling structure 104 is transferred via the at least one manifold structure channel 117a to a not depicted outlet. The at least one manifold structure channel 117a may be at least partially defined by the cover layer 114, the lid arrangement 116 and at least one manifold structure wall 117b. Optionally, the at least one manifold structure wall

[0295] August 28, 2025 35 / 44 117b may comprise a manifold structure wall aspect ratio, which refers to a ratio of the manifold structure wall’s 117b height and the manifold structure wall’s 117b width. The manifold structure wall aspect ratio may be between 1 and 20, or 1 and 18, or 1 and 15, or between 1 and 13, or between 1 and 11. The manifold structure wall aspect ratio may be at least 1. The manifold structure wall aspect ratio may be at most 20, or 18, or 15, or 13 or 11.

[0296] Optionally, the manifold structure wall 117b may separate the at least one manifold structure channel 117a from at least one inlet channel 136 which fluidly connects an inlet 120 of the lid arrangement 116 and the cooling structure layer 104 in particular the cooling structure channels. Optionally, a design of the at least one inlet channel 136 may correspond to a design of the inlet 120. For example, in case the inlet 120 is a slit, the inlet channel 136 may be also a slit.

[0297] Further, the manifold structure channel 117a may comprise a manifold structure channel width 117c, which may correspond to a maximum suitable overhang of the manufacturing process, as the lid arrangement 116 comprises an unsupported lid arrangement overhang, which covers the manifold structure channel 117a without being supported. For example, if the maximum allowable overhang may be 0.5 mm the manifold structure channel width 117c may be 1 mm.

[0298] Optionally, support structures may support a supported lid arrangement overhang, to extend the manifold structure channel width 117c.

[0299] The lid arrangement 116 may comprise several inlets 120, which are configured to conduct a cooling agent via the at least one inlet channel 136 to the cooling structure layer 104. The lid arrangement 116 may define at least one side of the manifold structure channels 117a, wherein a width of the manifold structure channels 117a may correspond to a double of a maximum allowable overhang. The maximum allowable overhang may depend on a material, on geometric characteristics, on a thickness of the lid arrangement 116, etc.

[0300] Optionally, the cold plate 100 may comprise additional layers, such that the cold plate may comprise 6, 7, 8, 9, 10, 11 , or 12 layers. For example, least one of the above described layers may be split into several sub-layers, which may contribute to facilitating production of the cooling plate 100.

[0301] Fig. 13 shows an embodiment of the coldplate 100 according to the above described embodiment of Fig. 12. The coldplate 100 comprises several layers, in particular the base layer 102, the cooling structure layer 104, the cover layer 114, the manifold structure 117 and the lid arrangement 116. The lid arrangement 116 comprises several inlets 120 and the outlet 122.

[0302] The inlets 120 are configured to conduct a cooling agent to the manifold structure 117, while the manifold structure 117 is configured to conduct the cooling agent to the cooling structure layer 104. The cooling structure layer 104 may comprise at least one not depicted three-dimensional

[0303] August 28, 2025 36 / 44 cooling structure, which is configured to transfer heat to the cooling agent. The cooling agent is utilized to transfer heat to a heat dump. The heated cooling agent is transferred from the cooling structure layer 104 through the manifold structure 117, in particular through the manifold structure channels 117a, to the outlet 122. Fig. 14 depicts a detailed view of Fig. 13, showing in particular the lid arrangement 116 having several inlets 120, the manifold structure 117 having several manifold structure channels 117a and several manifold structure walls 117b, the cover layer 114 having several orifices 118 and the cooling structure layer 104.

[0304] August 28, 2025 37 / 44

Claims

CR0006P-WQClaims1. Process of manufacturing a coldplate (100) for semiconductor cooling applications, the process comprising the steps• providing a base plate (102),• 3D screen printing at least one cooling structure layer (104) on top of the base plate (102) with a build rate, including depositing and curing the at least one cooling structure layer, between 15 and 8,500 cm3per hour to form a first three-dimensional cooling structure (106) within the coldplate (100) having critical dimensions between 25 and 200 pm and an aspect ratio between 1 and 80, wherein the first three-dimensional cooling structure (106) comprises at least one area (108) with a microstructure including a network of channels (110) for guiding a cooling agent, and two or more three-dimensional features (112) which contribute to the formation of boundaries of the channels of the network of channels (110).

2. Process according to claim 1 , further comprising the step of providing a cover layer (114) on top of the first three-dimensional cooling structure (106).

3. Process according to claim 1 or 2, wherein the first three-dimensional cooling structure (106) is formed by 3D screen printing at least two or multiple cooling structure layers (104), directly or indirectly, on top of each other.

4. Process according to at least one of the preceding claims, further comprising a drying or curing step, wherein a drying or curing time is between 2 s and 200 s, or between 10 s and 30 s, and / or the drying step occurs after printing at least one cooling structure layer (104).

5. Process according to at least one of the preceding claims, wherein a 3D screen printing time to print at least one cooling structure layer (104) is between 0.1 and 3s.

6. Process according to at least one of the preceding claims, wherein at least one further three-dimensional cooling structure (106) is formed within the coldplate (100) by providing, preferably 3D screen printing, an intermediate base plate on top of the first three-dimensional cooling structure (106), and3D screen printing at least one, at least two or multiple further cooling structure layers (104) on top of the intermediate base plate,August 28, 2025 38 / 44CR0006P-WQ the intermediate base plate preferably being provided with at least one inlet and / or at least one outlet for distributing cooling agent between the cooling structures.

7. Process according to at least one of the preceding claims, wherein the coldplate (100) is a metal coldplate, preferably a copper coldplate.

8. Process according to at least one of the preceding claims, wherein the base plate (102) and / or the cover layer (114) is provided by 3D screen printing, preferably with a build rate between 100 and 12,000 cm3per hour.

9. Process according to at least one of the preceding claims, wherein the base plate (102) and / or the cover layer (114) is provided as a separate part and is bonded to the at least one cooling structure layer (104), preferably by brazing or copper-copper diffusion bonding.

10. Process according to at least one of the preceding claims, wherein the base plate (102) is provided with at least one inlet and / or at least one outlet for guiding cooling agent to and / or from the cooling structure within the coldplate (100).

11. Process according to at least one of the preceding claims, wherein the cover layer (114) is provided with at least one inlet (120), at least one outlet (122), and / or multiple orifices (118) for guiding cooling agent to and / or from the cooling structure within the coldplate (100).

12. Process according to at least one of the preceding claims, comprising 3D screen printing at least one inlet and / or at least one outlet, preferably at least one inlet connector (132) and / or at least one outlet connector (134), for distributing cooling agent to and / or from the three- dimensional cooling structures (106).

13. Process according to at least one of the preceding claims, further comprising providing, preferably 3D screen printing, a manifold structure (124) within the coldplate (100) for distributing cooling agent within the coldplate (100), preferably providing the manifold structure (124) on top of the cover layer (114).

14. Process according to at least one of the preceding claims, further comprising providing, preferably 3D screen printing, a lid arrangement (116) within the coldplate (100).

15. Process according to claim 14, wherein the lid arrangement (116) has at least one inlet (128) and / or at least one outlet, the lid arrangement (116) preferably having a cover layer (114) having at least one inlet and a lid arrangement having at least one outlet, preferably providing the lid arrangement (116) as an outer top layer of the coldplate (100).

16. Process according to claim 14 or 15, wherein the first three-dimensional cooling structure (106) is arranged between the lid arrangement (116) and the base plate (102).August 28, 2025 39 / 4417. Process according to at least one of claims 14 to 16, wherein the first three-dimensional cooling structure (106) is at least partially supported by the lid arrangement (116).

18. Process according to at least one of claims 14 to 17, wherein the first three-dimensional cooling structure (106) has a high aspect ratio of between 6 and 70, or between7 and 65, or between 8 and 60, or between 9 and 50, or between 10 and 40.

19. Process according to at least one of claims 14 to 18, wherein the lid arrangement (116) is provided with at least one surface for bonding with the manifold (117).

20. Process according to at least one of claims 14 to 19, further comprising providing the lid arrangement (116) with a thermal contact surface.

21. Process according to at least one of the preceding claims, comprising the further step of curing the coldplate (100), wherein the curing is performed by sintering, thermal curing, UV curing, electron beam curing, chemical curing, microwave curing, induction curing, room temperature curing, or a combination thereof.

22. Process according to at least one of the preceding claims, wherein the channels of the network of channels (110) are interconnected.

23. Process according to at least one of the preceding claims, wherein the two or more three- dimensional features (112) comprise protrusions, regularly shaped fins, irregularly shaped fins, walls, pins and / or pillars.

24. Process according to at least one of the preceding claims, wherein the at least one cooling structure layer (104) has a thickness between 25 and 300 pm.

25. Process according to at least one of the preceding claims, wherein the base plate (102) and / or the cover layer (114) has a thickness between 10 pm and 2.0 mm.

26. Process according to at least one of the preceding claims, wherein the coldplate (100) has a thickness between 100 pm and 10 mm, and a cross-sectional surface area between 25 and 10,000 mm2.

27. Process according to at least one of the preceding claims, wherein at least two, at least three, at least four or more than four coldplates (100) are manufactured simultaneously within one process.

28. Process according to at least one of the preceding claims, wherein at least the first three- dimensional cooling structure (106) that is formed within the coldplate (100) comprises aAugust 28, 2025 40 / 44CR0006P-WC plurality of gaps having a longitudinal extension, and wherein the 3D screen printing is performed in the direction of the longitudinal extension of the plurality of gaps.

29. Process according to at least one of the preceding claims, wherein in a transition region between the base plate (102) and the cooling structure layer (104) at least one step is formed for providing a stepped, graduated or semi-continuous transition between the base plate (102) and the cooling structure layer (104).

30. Process according to at least one of the preceding claims, wherein the 3D screen printing comprises applying a paste having a particle size distribution of: d10 = between 5.0 pm and 8.0 pm, or 5.5 pm to 7.5 pm, or 6.0 pm to 7.0 pmpreferably 6.8425 pm, d50 = between 9.0 pm and 12.0, or 9.5 pm and 11.5 pm, or 10.0 pm and 11.0 pmpreferably 10.9138 pm, d90 = between 15.0 pm and 18.0 pm, or 15.5 pm and 17.5 pm, or 16.0 pm and 17.0 pm or d10 = between 2.5 pm and 5.0 pm, or 3 pm to 5.0 pm, or 3.5 pm to 4.5 pm, d50 = between 5 pm and 11 , or 6 pm and 10 pm, or 7.0 pm and 9 pm, d90 = between 10 pm and 16 pm, or 11 pm and 15 pm, or 12 pm and 14 pm wherein preferably the paste comprises spherical particles.

31. Process according to at least one of the preceding claims, wherein the 3D screen printing comprises applying a paste with particles, wherein a ratio R between an average particle diameter davgand the critical dimensions CD of the three-dimensional cooling structure (106) is between 0.02 and 0.8, preferably between 0.04 and 0.6, more preferably between 0.05 and 0.5.

32. Coldplate (100) for semiconductor cooling applications, the coldplate (100) comprising a base plate (102), a first three-dimensional cooling structure (106) disposed on top of the base plate (102), the first three-dimensional cooling structure (106) having critical dimensions between 25 and 200 pm and an aspect ratio between 1 and 80, wherein the first three-dimensional coolingAugust 28, 2025 41 / 44CR0006P-WC structure (106) comprises at least one area (108) with a microstructure including a network of channels (110) for guiding a cooling agent, and two or more three-dimensional features (112) which contribute to the formation of boundaries of the channels of the network of channels (110), wherein the first three-dimensional cooling structure (106) comprises at least one 3D screen printed cooling structure layer (104).

33. Coldplate (100) according to claim 26, wherein the base plate (102) and the first three- dimensional cooling structure (106) are 3D screen printed.

34. Coldplate (100) according to claim 26 or 27, wherein a manifold (117) is attached to the base plate (102) and / or the three-dimensional cooling structure (106), such as by diffusion bonding, brazing, a gasket, or / or adhesive.

35. Coldplate (100) according to at least one of claims 26 to 28, wherein the manifold (117) is fluidically coupled to the base plate (102) and / or the three-dimensional cooling structure (106) to provide at least one path for the cooling agent that enters, and one path for the cooling that leaves the three-dimensional cooling structure (106).

36. Coldplate (100) according to at least one of claims 26 to 29, wherein at least one inlet and / or one outlet connector (132, 134) is attached to the manifold (117), such that the manifold (117) and the base plate (102) and / or the three-dimensional cooling structure (106) combined create a closed path for cooling agent between the inlet and outlet connector (132, 134).

37. Coldplate (100) according to at least one of claims 26 to 30, being at least partially formed of a material comprising impurities comprising oxygen and / or carbon.

38. Coldplate (100) according to at least one of claims 26 to 31, wherein the impurities comprise oxygen between 0.005 and 0.009 wt.% and / or comprise carbon between 0.020 and 0.030 wt .% and / or comprise nitrogen between 0.00005 wt.% and 0.007 wt.%.

39. Coldplate (100) according to at least one of claims 26 to 32, wherein the material of the at least first three-dimensional cooling structure (106), preferably the complete coldplate (100), has a relative density of at least 95%, preferably at least 97%, more preferably at least 99%.

40. Coldplate (100) according to at least one of claims 26 to 33, wherein the first cooling structure has a surface roughness Ra between 0.2 and 3.0 pm or between 0.2 pm andAugust 28, 2025 42 / 4441. Coldplate (100) according to at least one of claims 26 to 34, comprising a cover layer (114) disposed on top of the first three-dimensional cooling structure (106).

42. Coldplate (100) according to at least one of the claims 32 to 41 , comprising a lid arrangement (116).

43. Coldplate (100) according to claim 42, wherein the lid arrangement having at least one inlet( 120) and / or at least one outlet (122), the lid arrangement (116) preferably having a cover layer (104) having at least one inlet and a lid arrangement (116) having at least one outlet, preferably the lid arrangement (116) being formed as an outer top layer of the coldplate (100).

44. Coldplate (100) according to claim 42 or 43, wherein the first three-dimensional cooling structure (106) is arranged between the lid arrangement (116) and the base plate (102).

45. Coldplate (100) according to at least one of claims 42 to 44, wherein the lid arrangement (116) at least partly supports the first three-dimensional cooling structure (106).

46. Coldplate (106) according to at least one of claims 42 to 45, wherein the lid arrangement (116) comprises at least one surface for bonding with the manifold (117).

47. Coldplate (100) according to at least one of claims 42 to 46, wherein the lid arrangement(116) comprises a thermal contact surface.

48. Coldplate (100) according to at least one of claims 43 to 47, wherein the cover layer (114) may comprise at least one unsupported cover layer overhang, wherein the unsupported cover layer overhang extends between 0.2 mm and 1.8 mm, or between 0.3 mm and1.5 mm, or between 0.5 mm and 1.2 mm, or between 0.7 mm and 1.1 mm.

49. Coldplate (100) according to at least one of claims 42 to 48, wherein a manifold structure(117) may comprise a manifold structure thickness which is thicker than a cooling structure layer (104) thickness.August 28, 2025 43 / 44

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