Apparatus and method for etching the surface of a semiconductor substrate

An apparatus for etching the surface of a semiconductor substrate, comprising:

• a texturing tank having an intermediate floor dividing the texturing tank into an upper area and a lower area, a tank inlet to the lower area, a tank outlet from the upper area, the tank inlet and tank outlet disposed proximate to one another on a side of the texturing tank, and a flow path for a process fluid from the tank inlet, through the lower area and upper area, and to the tank outlet;
• a preprocessing area in the flow path comprising a vertically oriented chamber opposite the side of the texturing tank on which the tank inlet and tank outlet are disposed, the preprocessing area connecting the lower area and the upper area passing around the intermediate floor and having a means for removing gasses and bubbles from the process fluid;
• a processing area in the upper area in the flow path, adjacent to and downstream of the preprocessing area;
• an entry diffuser vertically disposed between the preprocessing area and the processing area, the entry diffuser comprising a wall having a plurality of horizontal slots configured to create uniform, laminar flow in the process fluid throughout the processing area;
• an exit baffle vertically disposed between the processing area and the tank outlet proximate to the side of the texturing tank on which the tank inlet and tank outlet are disposed, the exit baffle comprising a wall having a plurality of horizontal slots configured to impede flow of the process fluid exiting the processing area;
• and
• means for introducing the semiconductor substrate into the processing area.