JPS62154620A - Plasma processor - Google Patents

Abstract

PURPOSE:To measure at good S/N ratio in a plasma processor by mounting an infrared spectroscope on one side and an independent plasma diagnosing infrared ray source on the other of a bell-jar for performing a plasma reaction of a plasma chemical vapor-phase deposition unit to obtain infrared rays having strong intensity. CONSTITUTION:A known infrared spectroscope body 9 and an independent infrared ray source 1 opposed through a bell-jar 12 to the body 9 are mounted on an elevationally movable trestle 11 on both sides of the bell-jar 12 for performing a plasma reaction. The light emitted from the source 1 is transmitted through a mirror system in a cover 4 and a slit 2 into a plasma in the bell-jar 12, and introduced by a mirror system in a cover 5 into the spectroscope 9. The optical path length from the source 1 to the spectroscope 9 can be shortened to approx. 1/2 by mounting the source 1. Thus, light having strong intensity can be introduced to measure at good S/N ratio.

Description

Detailed Description of the Invention (Technical field to which the invention pertains) The present invention relates to the production of various materials including amorphous silicon by plasma chemical vapor deposition, or the production of various materials by plasma etching. This invention relates to a plasma processing apparatus that diagnoses the plasma state during etching and controls the plasma process.

(Prior Art) Conventionally, plasma diagnostic methods include devices using fR quantity analysis, emission spectroscopy, laser-induced fluorescence, coherent anti-Stokes Raman spectroscopy, and the like.

Devices using mass spectrometry have the disadvantage that they do not accurately reflect the state of the plasma because the ionization efficiency of each molecule in the plasma differs. Although devices using emission spectroscopy can directly detect luminescent species in plasma,
Since the luminescent species are a minority component in the plasma, they have the disadvantage of being difficult to capture the entire image of the plasma. Devices using laser-induced fluorescence have the disadvantage that the state of the plasma changes because the plasma is irradiated with a laser and the molecules in the plasma are excited once.

Although devices using coherent anti-Stokes Raman spectroscopy are superior in the above points, they are extremely expensive and difficult to measure because the optical paths of two types of lasers must be aligned. There was a drawback.

On the other hand, there were measurement devices using infrared spectroscopy, but they were limited to model devices.

(1) Dry Process Symposium (J, Nis
hlN15hlza N, Hayasaka+ Pr
oc, Jnd Symp on DryProces
ses+ /910 Plo) (2) Applied technology symposium based on seven ion sources (H, H
amasaki+ M, Hirose and Y.

0saka+ Proc, lr th Symp o
n Ion 5 sources and Ion-Ass
isted Technology+ Tokyo+
/riIr2. P2 Otsu 3) Outline of these devices in Part 1.
As shown in the figure.

/ is an infrared light source, 2 is a sample measurement chamber, 3 is a spectrometer, ≠ is a gas cell, and evening is a high frequency generation electrode. That is, the conventional device has a structure in which an electrode for generating high frequency waves is built into a gas cell attached to an infrared spectrometer to generate plasma. In this structure, due to optical system constraints, it is not possible to separate Hiro's sample gas cell from the reference gas cell, and λ
The size of the sample measurement chamber is determined. Therefore, although a gas cell could be installed, there was a drawback in that it was not possible to install a Versier that performs a plasma reaction such as a practical plasma chemical vapor deposition device. In the method of extracting the side infrared rays to the outside using a mirror, transmitting them through the Verscia of a plasma chemical vapor deposition device, etc., and then guiding them back to the spectrometer in step 3, the optical path length becomes long, so the infrared rays required for infrared absorption analysis are The drawback was that infrared intensity could not be obtained.

(Objective of the Invention) The present invention solves these drawbacks by providing an infrared light source and an infrared spectrometer facing each other with a Pelger in between. This method is characterized by the use of infrared spectroscopy to form a thin film and perform etching processing for diagnosis.

(Structure of the Invention) The main feature of the present invention is that an infrared spectrometer is installed on one side and an independent infrared light source for plasma diagnosis is installed on the other side, sandwiching the Vercia that performs the plasma reaction of the plasma chemical vapor deposition apparatus. shall be. This method differs from the conventional technology in that by installing opposed infrared light sources, it is possible to diagnose plasma in an apparatus that actually performs chemical vapor deposition or etching using plasma. In addition, by installing this independent infrared light source, it is possible to shorten the optical path length of the infrared light emitted from the light source until it passes through the sample and enters the spectrometer, making it possible to obtain strong infrared light. , it has the characteristic of being able to perform measurements with good S/N ratio.

(Embodiment) FIG. 2 shows an embodiment of the present invention, in which l is an infrared light source, C is a slit, and 3 is an infrared transmitting window.

! is the cover, 6 and 7 are Hiro, the nitrogen gas inlet into the J' cover, ♂ is the plane mirror, and ri is the infrared spectrometer body. −
/ is the infrared light source of the infrared spectrometer, ter2 is the spectrometer, IO
is the process control device, 10-/ is the measurement system signal line, io-
1 is a process system control signal line, 1 is a movable stand, 1 is a Versia of a plasma chemical vapor deposition apparatus, and 13 is a bellows.

In the present invention, a ready-made infrared spectrometer main body is placed on both sides of a Versia for carrying out 12 plasma reactions, and an independent infrared light source is placed on a movable mount 1 that can be moved up and down. The structure is set up in The source emitted from the infrared light source at l passes through the mirror system inside the cover≠ and the slit at, and enters the plasma inside Bersia at /,2. passed,
cover! A system of internal mirrors guides the beam to an infrared spectrometer.

Here, which mirror is used to switch between light from the infrared light source Tar 1 with a built-in infrared spectrometer and light from Tar 1, and the infrared spectrometer is adjusted using the infrared light source of Tar 1.

Since an infrared light source has been installed at 1, when the source extracted from the infrared light source at 1 is transmitted through the Versier at 2 and then guided back to the spectrometer at 2, as in the conventional measurement system. Compared to this, the optical path length from the infrared light source l to the infrared spectrometer can be made approximately ten times shorter. Therefore, since high-intensity light can be guided to the spectrometer, good measurement of 8/N is possible.

Further, in this embodiment, the optical system 1Fc≠,j is installed inside the airtight structure cover member, and
2 and /3 are connected by bellows, so by introducing nitrogen gas or dry air from 6.7,
It is possible to prevent infrared rays from being absorbed by carbon dioxide and water in the optical path.

In addition, in this example, a horizontally long slit (for example, height, 2
The distribution of plasma chemical species existing between the upper and lower electrodes of the plasma enhanced chemical vapor deposition apparatus can be investigated by moving the 11 frame up and down.

For example, when attempting to diagnose 5iH4-Ht plasma using this device, SiH4 due to discharge as shown in Figure 3.
Changes in the amount and the formation of a new product 5in)16 in the gas phase shown in the @μ diagram can be investigated. In Figure 3, 2/r'? The changes in the absorbance of S i H4 appearing in I-1 are shown in the discharge (1) when the reaction gas is confined and the discharge (1) while the reaction gas is flowing. (2) was shown. In Figure μ, the solid line at 1 indicates the absorbance of 8 i 1 Ha, which was confirmed to be produced by a wooden fifK, and the broken line at 2 indicates that the presence of Si, H, cannot be detected with a conventional device due to poor 8/N. The results were shown. Furthermore, as described above, the combination of the horizontally elongated slit and the vertically movable mount makes it possible to measure the spatial distribution of these detected plasma components. 12 is a control device that controls the reaction gas supply system of the plasma chemical vapor deposition device and the plasma etching device based on the data obtained by diagnosing the plasma state; /2-1 is the signal line of the measurement system; 12-2 is a control signal line for the process system. By using these devices, it is possible to identify the plasma chemical species generated in Ziperger and to accurately diagnose the distribution of chemical species in the plasma simultaneously during thin film manufacturing and processing processes, so these diagnostic values can be used to improve plasma processing equipment. By controlling the reaction gas supply system, good OVD thin films and etching processes can be easily obtained.

(Effects of the invention) As explained above, if infrared spectroscopy is used for plasma diagnosis, plasma processing equipment can be constructed at a lower cost than other methods. Chemical 9i' can be identified. Another advantage is that by combining a slit and a vertically movable pedestal to allow dry nitrogen to flow through the source, the spatial distribution of chemical species in the plasma can be measured without interference from carbon dioxide or water. There is.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a conventional device, Fig. 2 is a plan view of an embodiment of the present invention, Fig. 3 is a change in the absorbance of SiH depending on the discharge time, and Fig. 81
It is the absorbance of 2H. Fig. 1 L...Infrared light source, K...Sample measurement chamber, 3
...Infrared spectrometer, ≠...Gas cell,! ...High frequency generation electrode WJλ diagram 7...Infrared light source, 2...Slit, 3
...Infrared transmission window 14. ! ...Cover, Otsu, 7.
...Gas inlet, r...plane mirror, r...infrared spectrometer body, ter/...infrared light source, ter! ...Infrared spectrometer /θ...Control device, 1o-i...Measurement system signal line, 10-2...Process system control signal line, //...
...Movable pedestal, /2...Perger, /3...Bellows Figure 3 l...S + H4f Changes in 81 eightsuke with respect to discharge time in a confined system. 2...Change in amount of SiH with respect to discharge time in a system where SiH4'< is flowing. Figure μ l... Wave number tttoc measured with this device
Absorbance of 8i H4-Ht plasma near n. λ: Absorbance of 8iH4-Hz plasma near wave number 11AO (sr') measured with a conventional device.

Claims (2)

[Claims] (1) In a plasma device that performs thin film formation and etching using plasma, through infrared transmission windows facing both sides of the Pelger that generates plasma,
An infrared light source that passes through the plasma from one of the infrared transmission windows, an infrared spectrometer that measures the infrared characteristics after the plasma has passed through the other infrared transmission window and diagnoses the plasma state, and the plasma diagnosis. A plasma processing device consisting of a control device to control thin film formation and processing processes based on values. (2) In the plasma process apparatus described in (1),
In order to measure the plasma distribution inside Peljar, a movable mount that moves the infrared light source and infrared spectrometer up and down at the same time,
A cover member having an airtight structure that covers the periphery of the infrared light source and the infrared spectrometer and has an opening only in the portion facing the infrared transmission window of Pelger, and the opening of the cover member and the infrared transmission window of Pelger are combined. A plasma processing apparatus characterized by comprising a bellows that