Method for preparing grounding substrate for semiconductor device

A method for preparing a grounding substrate for a semiconductor device, the method comprising:

• 1) polishing a surface of a matrix of a grounding substrate using a 320# sandpaper for texture treatment whereby removing a carbon layer therefrom, and washing the surface of the matrix with anhydrous ethanol;
• 2) providing a cold spray system comprising a spraying device, a spray chamber, and a special fixture disposed in the spray chamber;
• and disposing the matrix on the special fixture;
• 3) using the cold spray system to spray a compressed gas carrying aluminum powder on the surface of the matrix at a supersonic speed to form an aluminum coating, whereby obtaining the grounding substrate, wherein, parameters for a spraying process are as follows:
• a spray distance is between 5 and 50 mm, a gas pressure is between 0.5 and 4.5 megapascal, a gas temperature is between 150 and 500° C., a gas flow rate is between 5 and 50 g/s, a purity of the aluminum powder is above 90%, and a grain size of the aluminum powder is between 200 and 600 meshes;
• 4) disposing the grounding substrate in a heat treatment furnace, raising a temperature therein to between 100 and 500° C., and maintaining the temperature for between 1 and 5 hrs;
• and
• 5) wet polishing the grounding substrate using a scouring pad and ethanol for eliminating color differences on the surface of the matrix.