Polishing Device for Indium Phosphide Substrate, and Polishing Process

A polishing process for an indium phosphide substrate, which is implemented on the basis of the polishing device for an indium phosphide substrate, characterized in that the polishing process comprises the following steps:

• step (1):
• putting an indium phosphide substrate (5) into a substrate slot (17-1) of the planet gear (17-1);
• step (2):
• by virtue of the cathode lifting mechanism, enabling the polishing cloth (13) positioned on the lower end surface of the cathode disc (1) to contact the indium phosphide substrate (5), and keeping a polishing pressure between the cathode disc (1) and the graphite electrode plate (9) within a range of 40-400 g/cm2;
• step (3):
• injecting the electrolyte into the electrolyzer (3) through the polishing liquid injection assembly until the electrolyte immerses the cathode disc (1);
• step (4):
• driving, by virtue of the anode rotation driving mechanism and the cathode rotation driving mechanism, the cathode disc (1) and the graphite electrode plate (9) to rotate according to opposite directions, and at the same time, starting to inject polishing liquid through the polishing liquid injection assembly;
• and after the cathode disc (1) and the graphite electrode plate rotate (9) for 2-3 min, initiating the agitator (4), turning on the polishing DC power supply (20), and opening the stop valve of the electrolyte discharge pipe (12);
• step (5):
• after 9-12 min, turning off the polishing DC power supply (20) and shutting down the driving of the anode rotation driving mechanism and the cathode rotation driving mechanism;
• separating the cathode disc (1) from the graphite electrode plate (9) by virtue of the cathode lifting mechanism;
• positioning the indium phosphide substrate (5) above a liquid level of the electrolyte (6) by virtue of the anode lifting mechanism;
• and taking out the indium phosphide substrate (5);
• step (6):
• testing the roughness of a surface of the indium phosphide substrate (5) facing to an anode;
• when the roughness cannot meet a requirement, putting the indium phosphide substrate (5) into the substrate slot (17-1) in statu quo, and repeating the steps (2), (4) and (5);
• and when the roughness meets the requirement, reversing the indium phosphide substrate (5), putting the same into the substrate slot (17-1), and repeating the steps (2), (4) and (5);
• step (7):
• after polishing of both sides of the indium phosphide substrate (5) is completed, stopping the polishing liquid injection assembly from injecting the polishing liquid and the electrolyte, stopping the motion of the agitator (4), and emptying the electrolyte;
• and
• step (8):
• cleaning, drying and packaging the indium phosphide substrate (5) that meets a polishing requirement.