JPH07109038B2 - Etching processing device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an etching processing apparatus,
In particular, the present invention relates to an etching processing apparatus capable of accurately monitoring progress or completion of etching processing in a dry etching processing apparatus using glow discharge plasma.

[Prior Art] With the recent progress in ultra-miniaturization of semiconductor integrated circuits, so-called dry etching processing technology has been developed so that related materials can be processed with high precision and ultra-fineness. Has been put to practical use at the production site of.

By the way, when this dry etching technique is applied, it is difficult to completely control the purity of the gas selected for plasma generation, and the surface temperature of the material to be subjected to the etching tends to fluctuate. Due to the fact that the etching process is performed, the speed of the etching process varies. Therefore, it is generally necessary to monitor the progress and end of the etching process by some method. As means for performing such monitoring, for example, means for monitoring the intensity at a specific wavelength portion in the emission spectrum of the plasmatized gas, ions of a specific mass number, etc. Means for monitoring the detected intensity based on the corresponding mass spectrum are known. This is described in the magazine “Metal surface technology” Vol. 30, No. 5, 1979, p.
l, Al-based alloys, Si, SiO _{2 and the} like have been described for performing dry etching.

FIG. 2 is a block diagram showing a conventional etching processing apparatus having an etching end point detecting function. In FIG. 2, (1) is a vacuum chamber in which an appropriate etching process is performed on a predetermined workpiece. (2) is an etching control unit for controlling the overall operation of the etching processing apparatus.
A window portion (3) is provided at an appropriate position of the vacuum chamber (1) and is for monitoring the internal state of the vacuum chamber (1). (4) is a photoelectric exchange unit for converting the spectrum light corresponding to the progress of the etching process into an electric signal. Reference numeral (5) is an etching end detection unit for detecting the end point of the etching process based on the electric signal from the photoelectric conversion unit (4).

Next, the operation of the above conventional example will be described. First, a target work piece is housed in the vacuum chamber (1), and a required etching process for the work piece is started. Then, the spectral light generated in the vacuum chamber (1) corresponding to the progress of the etching process is applied to the photoelectric conversion section (4) through the window section (3) and converted into a corresponding electric signal, and then the etching is performed. It is applied to the end point detector (5). Then, the output from the etching end point detection unit (5) is applied to the etching control unit (2), and the overall control of the etching processing apparatus is performed.

Now, it is assumed that some product is generated in the vacuum chamber (1) in the process of the above-described etching process and the window portion (3) is fogged. As a result, the apparent intensity of the spectrum light generated in the vacuum chamber (1) changes, and the electric signal output correspondingly also changes, resulting in an error in detecting the etching end point. There is. In such a case, although the operator of the etching apparatus can take some measures by visually monitoring the state of the window portion (3), the window portion (3) is fogged. It is impossible to accurately correct the error in detecting the end point due to. Further, when the window portion (3) is extremely cloudy, it may be impossible to detect the electric signal from the photoelectric conversion portion (4).

[Problems to be Solved by the Invention] A conventional etching apparatus is configured as described above,
Since it is operated, the level of the electric signal detected when the inner surface of the window part for monitoring the internal state of the vacuum chamber becomes cloudy due to the products generated in the vacuum chamber. Therefore, a situation may occur in which the judgment necessary for the etching process becomes erroneous, or the detection of the electric signal itself becomes impossible. For this reason, it is necessary to stop the operation of the etching processing apparatus at the discretion of the operator who is operating the etching processing apparatus, or to remove the fog on the window as a maintenance work for the etching processing apparatus. However, there are problems such as the need for proper judgment by the operator in charge, the reduction in the overall working efficiency of the etching processing apparatus, and the like.

The present invention has been made in order to solve the above-mentioned problems, and monitors the fog condition of the window portion, and the progress of the etching process according to the result of monitoring the fog condition. Can be corrected,
Further, even if some fogging occurs in the window part, it is possible to accurately monitor the progress and end of the etching process. The function of detecting the fogging of the window part and the correction of the progress of the etching process are performed. An object is to obtain an etching processing apparatus having an etching end point detecting device having a function.

[Means for Solving Problems] The spectral intensity of plasma excitation light generated during etching processing on a workpiece in a vacuum chamber is monitored through a window portion provided in the vacuum chamber to determine the end point of the etching processing. In the etching processing apparatus, which is adapted to detect, a normal light storage unit in which a signal corresponding to the spectral intensity of normal light in which the fog of the window is within a predetermined range is stored in advance as a reference signal, and an actual condition from the window And a reference signal from the normal light storage unit to produce an output indicating the degree of fogging according to the result of comparison, and an actual output from the window unit based on the output of the fog monitoring unit. Equipped with an etching end point detection device including an etching end point detection unit that corrects the signal and detects the end point of the etching process It is characterized by that.

[Operation] In the present invention, the fogging monitor section in the attached etching end point detecting device is provided with the reference from the actual signal from the window part provided in the vacuum chamber and the normal light storage section in the etching end point detecting device. The signal of the above is compared, and a required correction command signal is applied to the etching end point detecting section in the etching end point detecting device depending on the result of the comparison.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a block diagram showing an etching processing apparatus provided with an etching end point detecting apparatus according to an embodiment of the present invention. In FIG. 1, (1) is a vacuum chamber in which an appropriate etching process is performed on a predetermined workpiece. (2) is an etching control unit for controlling the overall operation of the etching processing apparatus. A window portion (3) is provided at an appropriate position of the vacuum chamber (1) and is for monitoring the internal state of the vacuum chamber (1). Reference numeral (4) is a photoelectric conversion unit, and the spectral light corresponding to the progress of the etching process is converted into an electric signal, that is, the spectral intensity of the plasma excitation light generated during the etching process on the workpiece in the vacuum chamber (1). Is for converting into electric signals. Reference numeral (5) is an etching end point detection unit, which is an actual signal from the window unit (3) based on an output signal from a fog monitor unit (7) described later with respect to an electric signal from the photoelectric conversion unit (4). It is for correcting the signal and detecting the end point of the etching process.

Reference numeral (6) is a normal light storage unit that stores an electric signal output from the photoelectric conversion unit (4) as a reference signal when the cloudiness of the window unit (3) is within a predetermined allowable range. It is for storing. (7) is a fog monitor section, which is an actual electric signal from the photoelectric conversion section (4) and corresponding stored contents in the normal light storage section (6) (ie, a reference signal).
For producing an output indicating the degree of fogging depending on the result. Here, an etching end point detecting device (8) is constituted by the etching end point detecting part (5), the normal light storage part (6) and the fog monitoring part (7). Now, it is assumed that the window portion (3) is fogged while the etching processing apparatus having the above-described configuration is performing a required operation. And the degree of this cloudiness
For example, it is about 60% compared to a completely clear state, and the level of the electric signal applied from the photoelectric conversion part (4) to the etching end point detection device (8) side is the level at the normal time. Depending on the result of comparing the actual electric signal from the photoelectric conversion unit (4) with the reference signal from the normal light storage unit (6) by the fogging monitor unit (7), it may decrease by as much as 40%. An output indicating the degree of fogging is generated, and the actual electric signal from the photoelectric conversion unit (4) is corrected based on the output of the fogging monitor unit (7).
The etching end point detector (5) is corrected,
The end point of the etching process is accurately detected, and the degree of fogging of the window section (3) is accurately monitored based on the signal output from the fogging monitor section (7) to the etching control section (2). You can

[Effects of the Invention] As described above, in the etching processing apparatus according to the present invention, the spectral intensity of the plasma excitation light generated during the etching processing of the workpiece in the vacuum chamber is provided in the vacuum chamber. In an etching treatment apparatus which is designed to detect the end point of etching processing by monitoring through a window portion, a signal corresponding to the spectral intensity of normal light in which the fog in the window portion is within a predetermined range is stored in advance as a reference signal. An optical storage unit,
A fog monitor unit that generates an output indicating the degree of fog according to the result of comparing the actual signal from the window unit with the reference signal from the normal light storage unit, and based on the output of the fog monitor unit, Equipped with an etching end point detection device that consists of an etching end point detection part that corrects the actual signal from the window part to detect the end point of the etching process. Even if the level of the electrical signal of the etching process is lowered, it is not impossible to detect the end point of the etching process, and the end point of the etching process can be accurately detected. This has the effect of significantly improving the overall working efficiency of the device.

[Brief description of drawings]

FIG. 1 is a block diagram showing an etching processing apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing a conventional example. (1) is a vacuum chamber, (2) is an etching control unit,
(3) is a window part, (4) is a photoelectric conversion part, (5) is an etching end point detection part, (6) is a normal light storage part, (7)
Is a fogging monitor, and (8) is an etching end point detection device. In each drawing, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. The end point of the etching process is detected by monitoring the spectral intensity of the plasma excitation light generated during the etching process on the workpiece in the vacuum chamber through a window provided in the vacuum chamber. In the etching processing apparatus, a normal light storage unit that stores in advance a signal corresponding to the spectral intensity of normal light whose fog is within a predetermined range as a reference signal, an actual signal from the window unit, and the normal signal A fog monitor unit that generates an output indicating the degree of fog according to the result of comparison with the reference signal from the optical storage unit, and corrects the actual signal from the window unit based on the output of the fog monitor unit. An etching end point detection device including an etching end point detection unit that detects the end point of the etching process is provided. Etching processing apparatus.