Design and Pressure Optimized Control of an Electro-Hydraulic Servo Leveling System with Moment Compensation for Silver Sintering Packaging Equipment

The simultaneous sintering of chips with different specifications generates differential auxiliary sintering pressures, which create eccentric loads on the substrate. These loads disrupt the horizontal alignment of the chip-loading mold and adversely affect sintering quality. To overcome the challenge, an electro-hydraulic servo leveling system featuring active moment compensation is developed, incorporating high-precision pressure control to counteract the influence of eccentric loading. The system design is guided by static analysis to identify the eccentric load distribution, resulting in an optimized mechanical configuration. A feedforward-based Nussbaum gain backstepping adaptive controller is proposed to compensate for multiple nonlinear disturbances, including time-varying hydraulic parameters and external loads, while a feedforward strategy is integrated to improve the dynamic response of the pressure control loop. The effectiveness of the moment compensation leveling system and control algorithm has been validated through simulations and physical experiments on silver sintering equipment. The results show that the baseline deviation of the lower mold platform is reduced by 95%, achieving micron-level precision (≤5 μm). The proposed control algorithm reduces the dynamic tracking error by 42.4% and the steady-state fluctuation error by 50.6%. The introduction of the moment compensation leveling system to the existing silver sintering equipment addresses the issue of chip fracture caused by eccentric loading. The shear strength of the sintered layer is increased by 40.6%, and the thickness uniformity is improved by 65.8%. This study contributes to improved packaging quality and efficiency for power semiconductors, providing a theoretical basis for the development of advanced sintering equipment.