Methods of manufacturing semiconductive wafers and semiconductive material stencil masks

A method for manufacturing a semiconductive wafer comprising:

• providing a semiconductive material wafer having a front surface and a back surface;
• contacting the front surface with a first fluid;
• contacting the back surface with a second fluid different than the first fluid, at least one of the first and second fluids being configured to etch the semiconductive material of the wafer;
• at least one of the first and second fluids having a measurable characteristic, other than pH, that has a different value than any value of said measurable characteristic in the other of the first and second fluids;
• etching the semiconductive wafer with the at least one of the first and second fluids configured to etch the semiconductive material;
• and
• monitoring the measurable characteristic value in at least one of the first fluid or the second fluid to ascertain etch depth.

A method for manufacturing a semiconductive wafer comprising:

• providing a semiconductive material wafer having a front surface and a back surface;
• contacting the front surface with a first fluid;
• contacting the back surface with a second fluid different than the first fluid, at least one of the first and second fluids having a measurable characteristic that has a different value than any value of said measurable characteristic in the other of the first and second fluids and the first and second fluids converging after an opening is formed extending completely through the substrate;
• and
• monitoring the measurable characteristic value in at least one of the first fluid or the second fluid to ascertain if an opening has formed extending completely through the substrate.

A semiconductive wafer processing method comprising:

• providing a semiconductive material wafer having two opposing surfaces;
• contacting one of said opposing surfaces with a first fluid and contacting the other of said opposing surfaces with a second fluid different than the first fluid, a measurable characteristic, other than pH, having a different value in one of the first and second fluids than the other of the first and second fluids;
• etching the semiconductive wafer while contacting such wafer with the first and second fluids;
• and
• while etching, monitoring the measurable characteristic value in at least one of the first fluid or the second fluid to ascertain penetration of an opening through the semiconductive wafer.