Etching apparatus

• US 9,490,133 B2
• Filed: 01/24/2013
• Issued: 11/08/2016
• Est. Priority Date: 01/24/2013
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Inventors: Bao, Tien-I, Lee, Wan-Yu, Kuo, Ying-Hao, Chen, Hai-Ching
• Primary Examiner(s): Choi, Calvin
• Application Number:
  US13/749,119
• Publication Number:
  US 20140206110A1
• Time in Patent Office: 1,384 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: C09K 13/04 containing an inorganic acid
• CPC Class Codes: G01N 21/33 using ultraviolet light G01N21/39 takes precedence
• CPC Class Codes: H01L 21/0206 during, before or after processing of insulating layers
• CPC Class Codes: H01L 21/306 Chemical or electrical treatment, e.g. electrolytic etching to form insulating layers H01L21/31
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/30608 Anisotropic liquid etching H01L21/3063 takes precedence
• CPC Class Codes: H01L 21/31133 by chemical means
• CPC Class Codes: H01L 21/67075 for wet etching
• CPC Class Codes: H01L 21/67086 with the semiconductor substrates being dipped in baths or vessels
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

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.

Claims

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 H₂O₂.

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.