<p>Efficient thermal management in high-power electronic devices requires cooling channel designs that provide high heat removal while satisfying strict spatial and manufacturing constraints. This study presents a two-stage hierarchical topology optimization framework for cooling channels based on the Moving Morphable Components (MMC) method. The optimization is performed sequentially: in the first stage, only wall components are optimized to establish the global flow network and insignificant components are removed; in the second stage, the global structure is fixed and fin components are optimized to improve local thermal performance. The method is coupled with a two-layer thermofluid model using the Brinkman approximation and solved with the adjoint sensitivity approach. Across multiple inlet pressure conditions, the proposed framework consistently generates designs with clear functional separation. The results demonstrate that the two-stage optimization strategy effectively reduces the thermal objective while maintaining the intended role allocation between global flow-channel formation and local heat-transfer enhancement. Compared with a density-based topology optimization, the proposed method achieves a comparable final objective value using a simpler and more interpretable component-based representation, producing geometries that are more controllable and suitable for manufacturing-oriented design modifications.</p>