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DE-102024212247-B3 - Method for manufacturing a semiconductor unit and method for manufacturing a semiconductor device

DE102024212247B3DE 102024212247 B3DE102024212247 B3DE 102024212247B3DE-102024212247-B3

Abstract

Method for manufacturing a semiconductor unit (100) for a power converter, the method comprising a step of providing a printed circuit board apparatus comprising a printed circuit board (108) in which a power semiconductor (104) arranged on a substrate (102) is embedded, a step of removing a part of the printed circuit board (108) in order to at least partially expose a side of the substrate (102) facing away from the power semiconductor (104), and a step of forming a coolant guide structure (106) for guiding a liquid coolant in the substrate (102) starting from the side of the substrate (102) facing away from the power semiconductor (104).

Inventors

  • Sven Hutschneider
  • Andreas Zibold

Assignees

  • ZF FRIEDRICHSHAFEN AG

Dates

Publication Date
20260513
Application Date
20241220

Claims (11)

  1. A method (900) for manufacturing a semiconductor unit (100) for a power converter (1108), the method (900) comprising the following steps: Providing (902) a printed circuit board apparatus (200) comprising a printed circuit board (108) in which a power semiconductor (104) arranged on a substrate (102) is embedded; Removing (904) a portion of the printed circuit board (108) to at least partially expose a side of the substrate (102) facing away from the power semiconductor (104); and Forming (906) a coolant guide structure (106) for guiding a liquid coolant in the substrate (102) starting from the side of the substrate (102) facing away from the power semiconductor (104).
  2. Procedure (900) according to Claim 1 , wherein in step (904) of removal the part of the circuit board (108) is removed by drilling or milling.
  3. Method (900) according to one of the preceding claims, wherein in step (906) of forming a substrate layer (402) remains between the coolant guide structure (106) and the power semiconductor (104).
  4. Method (900) according to one of the preceding claims, wherein in step (906) of forming the coolant guide structure (106) is formed by etching in the substrate (102).
  5. Method (900) according to one of the preceding claims, wherein in step (902) of provisioning the substrate (102) is a silicon substrate, and/or wherein the power semiconductor (104) comprises an aluminum gallium nitride layer or a gallium nitride layer.
  6. Method (900) according to one of the preceding claims, wherein in step (902) of provisioning the printed circuit board (108) has at least one via (112) for electrically contacting a terminal of the power semiconductor (104).
  7. Method (900) according to one of the preceding claims, wherein in step (906) of the forming process a contact section (116) for electrically contacting the power semiconductor (104) via the substrate (102) remains adjacent to the coolant guide structure (106).
  8. Method (900) according to one of the preceding claims, wherein in the removal step (904) a further part of the printed circuit board (108) adjacent to the part of the printed circuit board (108) is removed in order to form a guide channel (1210) for guiding the liquid coolant along the printed circuit board (108).
  9. Method (900) according to one of the preceding claims, wherein in the provisioning step (902) the printed circuit board device (200) is provided, which has the printed circuit board (108) in which at least one additional power semiconductor (1200) arranged on an additional substrate (1204) is embedded, in the removal step (904) an additional part of the printed circuit board (108) is removed in order to at least partially expose a side of the additional substrate (1204) facing away from the additional power semiconductor (1200), and in the forming step (906) an additional coolant guide structure (1206) for guiding the liquid coolant in the additional substrate (1204) is formed starting from the side of the additional substrate (1204) facing away from the additional power semiconductor (1200).
  10. Method (1000) for manufacturing a semiconductor device (800) for a power converter (1108), wherein the method (1000) comprises the following steps: providing (1002) a first semiconductor unit (100) and a second semiconductor unit (100'), which are manufactured using a method (900) according to one of the Claims 1 until 9 manufactured units; and joining (1004) the first semiconductor unit (100) and the second semiconductor unit (100'), wherein the coolant guide structure (106) of the first semiconductor unit (100) and the coolant guide structure (106') of the second semiconductor unit (100') are arranged opposite each other to form a common cooling channel (802).
  11. Procedure (1000) according to Claim 10 , wherein the coolant guide structure (106) and the further coolant guide structure (106') are joined together directly or using intermediate pieces (804) in step (1004) of joining.

Description

The present invention relates to a method for manufacturing a semiconductor unit and to a method for manufacturing a semiconductor device. Additionally, a semiconductor unit, a power converter, an electric axle drive, and a motor vehicle are presented. Electrical components carrying current, such as power semiconductors, typically heat up, which is why cooling the components is common practice. State of the art is in US 2019 / 0 123 030 A1 , US 2024 / 0 162 116 A1 and US 2020 / 0 105 644 A1 revealed. Against this background, the present invention provides an improved method for manufacturing a semiconductor unit, an improved method for manufacturing a semiconductor device, an improved semiconductor unit, an improved power converter, an improved electric axle drive, and an improved motor vehicle according to the main claims. Advantageous embodiments are described in the dependent claims and the following description. The presented approach offers a way to increase the cooling surface area for electrical components, thereby improving heat dissipation. This can advantageously reduce the risk of malfunctions due to overheating. A method for manufacturing a semiconductor unit for a power converter is presented, wherein the method comprises a step of providing a printed circuit board apparatus having a printed circuit board in which a power semiconductor arranged on a substrate is embedded. The method further comprises a step of removing a portion of the printed circuit board to at least partially expose a side of the substrate facing away from the power semiconductor, and a step of forming a coolant guide structure for guiding a liquid coolant in the substrate from the side of the substrate facing away from the power semiconductor. The printed circuit board (PCB) assembly can represent a circuit carrier that may include one or more embedded power semiconductors. A power semiconductor, together with the substrate, can be, for example, a power transistor, such as a GaN-on-Si transistor, or another component suitable for high electrical currents or voltages. For the power converter mentioned as an example, the PCB assembly could include six or twelve embedded power transistors. The power semiconductor can be a component consisting of layers of different semiconductor materials with varying band gaps, such as gallium nitride (GaN), aluminum gallium nitride (AlGaN), or aluminum indium nitride (AlInN). Thus, the power semiconductor can be a high-electron mobility transistor (HEMT). The substrate can be silicon. The power semiconductor structures can be grown or deposited onto the substrate. The layered structure of the power semiconductor and substrate can also be referred to as a bare die, which may be embedded into the PCB. The printed circuit board (PCB) assembly can, for example, be designed as a blank that can be machined to produce the semiconductor unit. The PCB itself can be designed, for example, as a printed circuit board (PCB) that can serve as a substrate for electronic components. The coolant flow structure can advantageously form a plurality of cooling channels, thus creating a multitude of contact surfaces for the liquid coolant. This allows the liquid coolant to flow directly through a section of the substrate, resulting in very efficient heat dissipation. According to one embodiment, the portion of the circuit board can be removed by drilling or milling during the removal step. Advantageously, known methods can be used, thereby saving manufacturing costs. During the insertion step, a substrate layer can remain between the coolant conduction structure and the power semiconductor. This substrate layer prevents direct contact between the liquid coolant and the power semiconductor. Advantageously, this allows the use of any liquid coolant, thus reducing costs. Furthermore, the remaining substrate layer eliminates the need for electrical insulation of the coolant. According to one embodiment, the coolant guide structure can be formed in the substrate by etching during the forming step. Advantageously, the coolant guide structure can be introduced into the substrate very precisely by laser etching or fluid etching. In the provisioning step, the substrate can be a silicon substrate. Thus, one can rely on a A substrate known in connection with semiconductors can be used. The power semiconductor can have an aluminum gallium nitride layer and a gallium nitride layer. Advantageously, this material combination allows for high electrical conductivity and enables high operating voltages. According to one embodiment, during the molding step, the coolant guide structure can be formed in the substrate in a rib-like, labyrinthine, or pin-like manner. The coolant guide structure advantageously increases the cooling surface area between the liquid coolant and the substrate. Furthermore, the flow direction of the liquid coolant can be controlled. During the assembly step, the printed circuit board (PCB) can have at least