Browse Prior Art Database

End Point Detection (EPD) logic

IP.com Disclosure Number: IPCOM000013225D
Original Publication Date: 2002-Jan-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 3 page(s) / 103K

Publishing Venue

IBM

Abstract

Disclosed is a calculation logic for the endpoint monitoring system that is used to detect the end of process, such as the in-situ cleaning of PECVD (Plasma Enhanced Chemical Vapor Deposition) or dry etching of RIE (Reactive Ion Etcher) in a semiconductor manufacturing and a liquid crystal display manufacturing. This calculation logic can provide the error compensation for the threshold that is used for the process end detection and can tell more accurate end time.

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End Point Detection (EPD) logic

   Disclosed is a calculation logic for the endpoint monitoring system that is used to detect the end of process, such as the in-situ cleaning of PECVD (Plasma Enhanced Chemical Vapor Deposition) or dry etching of RIE (Reactive Ion Etcher) in a semiconductor manufacturing and a liquid crystal display manufacturing. This calculation logic can provide the error compensation for the threshold that is used for the process end detection and can tell more accurate end time.

Delta time

Standard Threshold case

Load voltage differential (V/sec)

2

1.6

1.2

0.8

0.4

0

1

0.8

0.6

0.4

0.2

Compansated Threshold case

Standard Threshold

Load voltgae (V)

(b)

0

0 5 10 15 20 25 30 35 40 45 50 55 60


(a)

Figure 1

Figure 1 shows the variety of the endpoint signal that obtained during in-situ cleaning of PECVD after the deposition of different film thicknesses. The left signal is for thinner film deposition and the right signal is for thicker film deposition. In this case, if the threshold that is suitable for the right signal is applied to the left one, this causes some errors in the end time. Figure 2 shows the relationship between deposited film thickness and cleaning end time that was detected by the same threshold, that was fixed threshold, this figure indicates some varieties of the end time in the thinner film thicknesses. Newly developed calculation logic can compensate these varieties.

Cleaning time (sec)

1

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70

50

30

60

40

20

End time (sec)

Thin film

0 0.5 1 1.5 2 2.5

Thickness (nm)

R2 = 0.95 N = 10 y = 23.6 + 17.1x

Figure 2

New calculation logic: The newly developed logic uses the differences of the detection signal slope at initial phase that showed (b) or (a) region in figure 1. Although the end time of figure 2 was calculated using fixed standard threshold as 0.01V/sec, figure 3 showe...