JPS61110433A - Method for measuring uniformity of etching processing - Google Patents

Abstract

PURPOSE:To measure uniformity of etching processing by utilizing aging of particular light emitting spectrum during the etching of sample to be used for judging the end point of etching. CONSTITUTION:A signal such as a particular light emitting spectrum intensity waveform 8 recorded by a pen recorder 4 with the time is input to an operation apparatus 5. When etching completes even at a point in the sample 2, the particular light emitting spectrum intensity suddenly starts to reduce like a point A. when etching further advances, the particular light emitting spectrum intensity reaches the point B and starts to saturate. Thereby, the time from start of etching to sudden reduce of particular light emitting spectrum intensity and the time from start of etching to start of saturation after sudden reduce of particular light emitting spectrum are obtained and thereby uniformity of etching for sample can be calculated and measured using obtained times.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a) method for measuring etching uniformity, particularly etching processing of a sample that is etched by dry etching such as plasma etching or reactive sputter etching. The present invention relates to an etching process uniformity measuring method suitable for measuring uniformity.

[Background of the invention]

As a technique for monitoring the nibutin state of a sample by dry etching such as plasma etching or reactive sputter etching, there is one example of a technique for monitoring the nibutin state of a sample by dry etching such as plasma etching or reactive sputter etching. A method is known in which the end point of etching is determined based on the change over time in the intensity of a specific emission spectrum of a molecule.

However, such techniques only determine the end point of etching based on the change over time in the intensity of a specific emission spectrum, but do not recognize that the uniformity of the etching process can be measured based on the change over time in the intensity of the specific emission spectrum. Note that the uniformity of the etching process is generally calculated and measured by the variation in the etching rate in each part of the sample during etching. In this case, there is a risk of damaging the etched sample when measuring variations in etching rate.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an etching process uniformity measuring method that can measure the etching process uniformity of a sample based on the temporal change in the intensity of a specific emission spectrum during etching of the sample.

[Summary of the invention]

The present invention calculates and measures the uniformity of the etching process on a sample based on the time from the start of etching until the intensity of a specific emission spectrum begins to rapidly decrease, and the time from the start of etching until the intensity of a specific emission spectrum begins to saturate after a sudden decrease. This method is characterized by the fact that the uniformity of the etching process on the sample is measured by the time-dependent change in the intensity of a specific emission spectrum during the kneeling of the sample, which is used to determine the end point of etching.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 1 and 2.

In FIG. 1, the etching end point of a sample 2 being etched in an etching chamber 1 is measured by an etching end point determination monitor 3, and a specific emission spectrum intensity waveform is recorded by a pen recorder 4. Further, the uniformity of the etching process is calculated by the arithmetic unit 5 using the data measured by the etching end point determination monitor 3, and is displayed on the CRT 6 and stored in the floppy disk 7.

Figure 1! In Figure J2, a signal such as the specific emission spectrum intensity waveform 8 recorded by the pen recorder 4 over time is input to the calculation bag W5.

When etching is completed at even one location within the sample 2 (in all samples in the case of a batch method), the intensity of the specific emission spectrum begins to decrease rapidly as shown at point A in FIG. As the etching progresses further, the specific emission spectrum intensity reaches point B where it begins to saturate. The method of detecting each point A and B may be regarded as Tm+n+TMAX. As another method, Tml n + TM AX may be obtained by performing differentiation once or twice. Tmin, TMAX and sample 2 obtained by this method
Using the film thickness t (nm), the etching rate, that is, the uniformity of the etching process, can be approximately calculated using equation (1).

Furthermore, if t is removed from equation (1), then TMAX and Tmta are obtained, and the uniformity of the etching process is calculated and measured using equation (2).

According to this embodiment, the following effects can be obtained.

(1) The uniformity of the etching process can be measured based on the change over time in the intensity of a specific emission spectrum during etching of a sample used to determine the end point of etching.

(2) The uniformity of the etching process can be measured without damaging the etched sample.

(3) It is possible to provide one piece of information to the inspection process for a sample being etched, such as a semiconductor device, and to improve the reliability of the dry etching apparatus itself.

In addition to this embodiment, simply TMAX Tmin
The value of (sec) may be taken as a data, and the uniformity of the etching process may be calculated and measured using this value.

〔Effect of the invention〕

As explained above, the present invention has the advantage that the uniformity of the etching process can be measured based on the change over time in the intensity of a specific emission spectrum during etching of a sample used for determining the end point of etching.

[Brief explanation of the drawing]

! ! FIG. 1 is a schematic diagram showing an example of a dry etching apparatus embodying the present invention, and FIG. 2 is a schematic diagram of a specific emission spectrum intensity waveform changing over time.

Claims (1)

[Claims] 1. In a method of measuring the uniformity of etching treatment of a sample subjected to dry etching treatment, the time from the start of etching until the intensity of a specific emission spectrum begins to rapidly decrease;
Etching process uniformity characterized by determining the time from the start of etching until the specific emission spectrum intensity suddenly decreases and begins to saturate, and using the determined time to calculate and measure the uniformity of the etching process of the sample. Gender measurement method.