A machine to etch facets of wafers in a column


The machine is used to etch facets of semiconductor wafers (up do the diameter of 4“) with a mixture of nitric acid, hydrofluoric acid and acetic acid. After the etching process is over, the wafers are rinsed in a triple upstream cascade with demineralised water and they are dried with air blown by means of flat nozzles.

The etch tub is filled with a mixture of nitric acid, hydrofluoric acid and acetic acid in an adjustable ratio. The etch tub is manufactured from the material PVDF. The etch tub is closed with an automatic lid.

The machine is equipped with a manipulator which enables semiautomatic operation. The manipulator is located in the etching space, separated from the operator with transparent covers and with sliding door. The manipulator ensures movement of a clamping fixture with wafers in horizontal and vertical direction. Having the fixture with wafers been immersed in the chemical bath, a vertical movement of an arm is carried out by means of a compressed-air cylinder for better washing and this movement is completed with controlled shocks in order to remove superficial bubbles. While the clamping fixture is moving from the rinse tub into the etch tub, the surface of the hook is blown with pressure air from four nozzles.

(The machine is used in Czech Republic by Swiss customer.)