METHOD FOR MANAGING UV IRRADIATION FOR CURING SEMICONDUCTOR SUBSTRATE

• US 20090023229A1
• Filed: 07/19/2007
• Published: 01/22/2009
• Est. Priority Date: 07/19/2007
• Status: Active Grant

• Current Assignee: ASM Japan K.K. (ASM International NV)
• Original Assignee: ASM Japan K.K. (ASM International NV)
• Inventors: MATSUSHITA, Kiyohiro, KAGAMI, Kenichi
• Granted Patent: US 7,501,292 B2
• Time in Patent Office: Days
• US Class Current: 438/7
• CPC Class Codes: H01L 21/67115 mainly by radiation
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

A method for managing UV irradiation for curing a semiconductor substrate, includes: passing UV light through a transmission glass window provided in a chamber for curing a semiconductor substrate placed in the chamber; monitoring an illuminance upstream of the transmission glass window and an illuminance downstream of the transmission glass window; determining a timing and/or duration of cleaning of the transmission glass window, a timing of replacing the transmission glass window, a timing of replacing a UV lamp, and/or an output of the UV light based on the monitored illuminances.

Claims

1. A method for managing UV irradiation for curing a semiconductor substrate, comprising:

passing UV light through a transmission glass window provided in a chamber for curing a semiconductor substrate placed in the chamber;

monitoring an illuminance upstream of the transmission glass window and an illuminance downstream of the transmission glass window to monitor UV light transmissivity of the transmission glass window; and

determining a timing and/or duration of cleaning of the transmission glass window, a timing of replacing the transmission glass window, a timing of replacing a UV lamp, and/or an output of the UV light based on the monitored UV light transmissivity of the transmission glass window.

2. The method according to claim 1, wherein the monitoring step comprises measuring the illuminance upstream of the transmission glass window by an illuminometer provided upstream of the transmission glass window and the illuminance downstream of the transmission glass window by an illuminometer provided downstream of the transmission glass window, thereby obtaining a transmissivity of the UV light.

3. The method according to claim 1, wherein the passing UV light step and the monitoring step are performed at least at one time selected from the group consisting of a start of curing of the semiconductor substrate, an end of curing of the semiconductor substrate, a start of cleaning of the transmission glass window, and an end of cleaning of the transmission glass window.

9. The method according to claim 3, wherein the passing UV light step and the monitoring step are repeated after a different semiconductor substrate is loaded in the chamber.

10. The method according to claim 9, wherein the determining step comprises comparing the illuminances monitored downstream of the transmission glass window in the respective monitoring steps, thereby determining the timing of replacing the transmission glass window.

11. The method according to claim 9, wherein the determining step comprises comparing the illuminances monitored in the respective monitoring steps, thereby determining the timing of cleaning the transmission glass window.

12. The method according to claim 1, wherein the passing UV light step and the monitoring step are performed frequently or continuously during cleaning, thereby determining an endpoint of the cleaning.

13. The method according to claim 3, wherein the determining step comprises determining the output of the UV light, and the method further comprises increasing the output of the UV light based on the determined output of the UV light determined to maintain the illuminance of the UV light passing through the transmission glass window.

14. The method according to claim 1, wherein the determining step comprises determining the timing of cleaning by setting a threshold value of illuminance to initiate cleaning and comparing the monitored illuminance downstream of the transmission glass window with the threshold value of illuminance.

16. The method according to claim 1, wherein the UV light has a wavelength of 170 nm to 300 nm.

4. A method for managing UV irradiation for curing a semiconductor substrate, comprising:

passing UV light through a transmission glass window provided in a chamber for curing a semiconductor substrate placed in the chamber;

monitoring an illuminance upstream of the transmission glass window and an illuminance downstream of the transmission glass window; and

determining a timing and/or duration of cleaning of the transmission glass window, a timing of replacing the transmission glass window, a timing of replacing a UV lamp, and/or an output of the UV light based on the monitored illuminances,

wherein the passing UV light step and the monitoring step are performed at least at one time selected from the group consisting of a start of curing of the semiconductor substrate, an end of curing of the semiconductor substrate, a start of cleaning of the transmission glass window, and an end of cleaning of the transmission glass window,

wherein the determining step comprises;

comparing the illuminance downstream of the transmission glass window with a first reference value;

comparing the illuminance upstream of the transmission glass window with a second reference value;

determining to initiate cleaning of the transmission glass window if the illuminance downstream of the transmission glass window is equal to or lower than the first reference value and the illuminance upstream of the transmission glass window is not equal to or lower than the second reference value; and

determining to replace the UV lamp if the illuminance upstream of the transmission glass window is equal to or lower than the second reference value.

5. The method according to claim 4, wherein when the cleaning is initiated, the passing UV light step and the monitoring step are repeated during the cleaning and the determining step further comprises:

comparing the illuminance downstream of the transmission glass window monitored with a third reference value; and

determining to end cleaning of the transmission glass window if the illuminance downstream of the transmission glass window is equal to or higher than the third reference value.

6. The method according to claim 5, wherein when the illuminance downstream of the transmission glass window is not equal to or higher than the third reference value, the determining step further comprises:

comparing the illuminances consecutively monitored downstream of the transmission glass window; and

determining to end cleaning of the transmission glass window if a difference between the consecutively monitored illuminances downstream of the transmission glass window is equal to or less than a standard value.

7. The method according to claim 6, wherein the determining step further comprises:

determining to increase the output of the UV light to compensate for a differenced between the illuminance downstream of the transmission glass window at the end of the cleaning and the third reference value.

8. The method according to claim 7, wherein the determining step further comprises:

comparing the illuminance downstream of the transmission glass window upon the increase of the output of the UV lamp with a fourth reference value; and

determining to replace the transmission glass window if the illuminance downstream of the transmission glass window upon the increase of the output of the UV lamp is equal to or lower than a standard value.

15. A method for managing UV irradiation for curing a semiconductor substrate, comprising:

passing UV light through a transmission glass window provided in a chamber for curing a semiconductor substrate placed in the chamber;

monitoring an illuminance upstream of the transmission glass window and an illuminance downstream of the transmission glass window; and

determining a timing and/or duration of cleaning of the transmission glass window, a timing of replacing the transmission glass window, a timing of replacing a UV lamp, and/or an output of the UV light based on the monitored illuminances,

wherein the determining step comprises determining the timing of replacing the transmission glass window by setting a threshold value of illuminance to replace the transmission glass window and comparing the monitored illuminance downstream of the transmission glass window with the threshold value of illuminance.

17. A method for curing a semiconductor substrate by UV light, comprising:

(i) curing a semiconductor substrate placed in a chamber by passing UV light through a transmission glass window provided in the chamber, in an atmosphere of a gas selected from the group consisting of Ar, CO, CO₂, C₂H₄, CH₄, H₂, He, Kr, Ne, N₂, O₂, Xe, alcohol gases, and organic gases;

(ii) cleaning the transmission glass window using a cleaning gas;

(iii) monitoring an illuminance upstream of the transmission glass window and an illuminance downstream of the transmission glass window during step (i) and/or (ii), thereby determining a timing and/or duration of cleaning of the transmission glass window, a timing of replacing the transmission glass window, a timing of replacing a UV lamp, and/or an output of the UV light based on the monitored illuminances; and

(iv) according to step (iii), controlling the timing and/or duration of step (ii), replacing the transmission glass window, replacing the UV lamp, and/or increasing the output of the UV light in step (i).