Etching apparatus
A system and method of etching a semiconductor device are provided. Etching solution is sampled and analyzed by a monitoring unit to determine a concentration of components within the etching solution, such as an oxidant concentration. Then, based upon such measurement, a makeup amount of the components may be added be a makeup unit to the etching solution to control the concentration of the components within the etching system.
1. A system for etching a semiconductor device comprising:
a primary etch tank configured to hold an etchant;
a monitoring unit comprising an oxidant analysis unit; and
a makeup unit comprising:
an oxidant storage unit for storing an oxidant;
a base storage unit for storing a base; and
a surfactant storage unit for storing a surfactant;
a mixing unit coupled to a first output from the oxidant storage unit, a second output from the base storage unit, and a third output from the surfactant storage unit.
2. The system of claim 1 , wherein the oxidant analysis unit is an oxidation reduction potential measurement unit.
3. The system of claim 1 , wherein the oxidant analysis unit is an optical spectrum analysis unit.
4. The system of claim 3 , wherein the optical spectrum analysis unit is a UV absorption spectrum analysis unit.
5. The system of claim 1 , wherein the oxidant analysis unit comprises:
an oxidation reduction potential measurement unit; and
an optical spectrum analysis unit.
6. The system of claim 1 , wherein the oxidant is H 2 O 2 .
7. The system of claim 1 , further comprising:
a recirculation line; and
a by-pass line connected to the recirculation line and to the monitoring unit.
8. A system for etching a semiconductor device comprising:
an etching tank configured to hold an etchant with an inlet port, and outlet port, and a makeup port;
a recirculation line connected to the inlet port and the outlet port, the recirculation line comprising a filter to remove an oil chemical-reaction by-product, wherein the etching tank and the recirculation line are an etching system;
a by-pass line connected between the etching system and a monitoring system, the monitoring system comprising an oxidant analysis unit; and
a makeup unit in communication with the monitoring system, the makeup unit comprising an oxidant makeup storage unit.
9. The system of claim 8 , wherein the makeup unit is in communication with the monitor system through a microcontroller.
10. The system of claim 8 , wherein the monitoring system further comprises a cooler.
11. The system of claim 8 , wherein the makeup unit further comprises:
a makeup base storage unit; and
a makeup surfactant storage unit.
12. The system of claim 8 , wherein the outlet port is an overflow reservoir.
13. The system of claim 8 , wherein the oxidant analysis unit further comprises:
an oxidation reduction potential measuring unit; and
an optical spectrum analysis unit.
14. The system of claim 13 , wherein the monitoring system further comprises a surfactant measurement unit.
15. A system for etching a semiconductor device, the system comprising:
an etching tank configured to hold an etchant;
a recirculating pump to pump etchant through a recirculation line;
a monitoring unit comprising:
a sample valve connected to the recirculation line;
an oxidant analysis unit connected to the sample valve, wherein the oxidant analysis unit comprises an oxidation reduction potential measurement unit;
a makeup unit comprising:
an oxidant storage unit with a first outlet;
a base storage unit with a second outlet;
a surfactant storage unit with a third outlet;
a mixing unit coupled to the first outlet, the second outlet and the third outlet, the mixing unit comprising a fourth outlet; and
an makeup line connecting the fourth outlet to the etching tank.
16. The system of claim 15 , further comprising a solvent makeup line connected to the mixing unit.
17. The system of claim 15 , further comprising a controller connected to both the monitoring unit and the makeup unit.
18. The system of claim 15 , further comprising a chilling unit connected to an output of the sample valve.
19. The system of claim 15 , wherein the makeup unit is a titration unit.
20. The system of claim 15 , wherein the etching tank further comprises a weir.