JPH0478136B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an excitation emission intensity measurement device that receives light emission from an excited element and measures its intensity.

2. Description of the Related Art Recently, with the development of vacuum equipment, thin film formation is almost always carried out in a vacuum. In particular, magnetron sputtering has significantly improved its ability to form thin films and is now replacing vacuum evaporation. On the other hand, in the ion plating method, a part of the evaporation material can be ionized and accelerated by an electric field, so that it is possible to form a thin film firmly adhered to the substrate to be evaporated. However, when forming a thin film using these methods, the problem is how to measure the thin film and the rate of thin film formation. Particularly when forming an alloy thin film with a constant composition, the thin film formation rate is very important. Conventionally, these amounts have been determined by using a quartz crystal resonator, depositing a thin film-forming substance on the resonator, and reading the amount from changes in the oscillation frequency. However, with this method, it is impossible to continuously measure a large amount of thin films.

Therefore, recently, attempts have been made to measure the above-mentioned film formation rate, etc. from the amount of light emitted by elemental excitation by plasma. For example, when a thin film is formed by a sputtering method or a plasma deposition method, light emission is clearly observed. In this method, since the luminescent material is constantly supplied, the luminescence phenomenon does not stop, and by making effective corrections, it is possible to continuously and accurately control the thin film formation rate and composition of a large amount of thin films.

In fact, the sputtering method has already been put to practical use, such as in the formation of ITO Nesa films. Conversely, when a thin film formed on a substrate is removed by plasma etching, the end point is detected using a light emission monitor.

On the other hand, for vapor deposition that does not involve an excited luminescence phenomenon, a light emitting source such as a hollow cathode lamp is used, and the material element absorbs the light from the light source and is excited, making use of the atomic absorption phenomenon. A method is used to measure the material element vapor concentration from the absorbed amount.

Problems to be Solved by the Invention However, when attempting to measure the thin film formation rate, etc. from the plasma emission intensity, a problem opposite to that of a quartz crystal resonator occurs. That is, there is a problem in that material in the plasma is scattered by the plasma and enters the light inlet for observing the plasma emission intensity, thereby staining the observation window. An example of this is shown in FIG. In Figure 3, 1 is a plasma light emitter, 2 is an observation light inlet, 3 is a condensing lens, and 4
5 is an observation light introduction tube, 5 is an observation window, and 6 is a bell jar wall. In this example, an observation window 5 is installed in a part of the bell jar wall 6. In this case, the material scattered by the plasma emitter 1 passes through the observation light introduction port 2 and directly adheres to the observation window 5. Therefore, the light transmittance of the observation window 5 changes,
In this state, it was impossible to observe plasma emission with high precision over a long period of time.

To solve this problem, an attempt was made to install a light-transmitting film 7 just in front of the observation window 5 and gradually roll it up to prevent the observation window 5 from getting dirty, as shown in FIG. was. 8 is a film roll. However, in this case, since the translucency of light is utilized, most of the material is organic film, and metal films cannot be used. Therefore, there is no problem if the plasma emission to be observed is on the longer wavelength side than 350 nm, but the emission wavelength of most materials is on the short wavelength side (for example, Te = 200 nm, pd =
250nm, p=250mm, etc.). When such emission wavelengths are included, the transmission characteristics of the organic film become substantially zero, making it no longer possible to measure the emission intensity.

For this reason, some methods have been adopted in which a mirror is installed in the observation light introduction tube up to the observation window, and the emitted light is reflected by this mirror, and sputter gas is sprayed onto this mirror to prevent the adhesion of material particles. It is being However, according to our experiments, with this method, adhesion cannot be prevented unless gas is blown at a rate of 40 c.c. or more per minute, which puts a considerable load on a normal exhaust system, making it impractical.

In the case of vapor deposition, a hollow cathode lamp 9 is shown in FIG.
This shows the atomic absorption method using . In this case, since there are two observation windows 5, contamination of the upper air becomes a more serious problem. Note that 10 is a vapor deposition vapor.

Means for Solving the Problems In order to solve the above problems, the excitation emission intensity measuring device of the present invention includes an observation light introduction tube forming a substantially L-shaped observation light introduction path, and an observation light introduction tube that forms a substantially L-shaped observation light introduction path. It has a structure that includes a metal thin film that is placed at a corner of the introduction tube and has a good reflectance for the emission wavelength of the excited element, and a winding means that winds up the metal thin film at a predetermined speed. be.

Effect According to the above configuration, the material particles that have entered the observation light introduction path adhere to the metal thin film, so that
It is possible to prevent measurement errors caused by fluctuations in light transmittance due to material particles during plasma emission adhering to the observation window. Furthermore, since the metal thin film is wound up at a predetermined speed by the winding means, the excitation light can always be reflected by the metal thin film to which less material particles are attached, making it possible to perform measurements with high precision.

Embodiment Hereinafter, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of the main parts of an excitation emission intensity measuring device according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the main parts, which are the same as the components shown in FIGS. 3 to 5. The same reference numerals are given to the constituent elements, and the explanation thereof will be omitted. In FIGS. 1 and 2, 11 is a metal thin film, and 12 is a winding motor. An observation light introduction tube 4 consisting of a hollow tube with one L-shaped end located near the plasma light emitting body 1 is provided, and a thin hole is formed at the tip of this observation light introduction tube 4 to be used for observation. This is the light introduction port 2. At the corner of the observation light introduction tube 4, there is an observation light introduction port 2.
The metal thin film 11 is arranged at a predetermined angle so that the light from the observation window 5 passes through the condensing lens 3 and the observation window 5.

Next, the operation will be explained. First, a considerable portion of the material particles scattered by the plasma light emitter 1 is blocked by the wall around the observation light introduction port 2 . However, some particles enter the observation light introduction tube 4 through the observation light introduction port 2. On the other hand, the emitted light of the plasma is reflected by the metal thin film 11 for reflection, and guided into the outside atmosphere through the observation window 5 while being focused by the focusing lens 3. Most of the material particles that have entered the observation light introduction cylinder 4 adhere to the metal thin film 11. Therefore, material particles cannot enter further.

Note that it is preferable to use aluminum as the metal thin film 11. This is because aluminum has a reflectance of approximately 95% or more over a wavelength range of 200 nm to 1 μm. Further, the metal thin film 11 does not need to be entirely made of metal. i.e. on a regular film base
It is most preferable to use an aluminum coating with a thickness of 500 Å or more.

Now, by introducing such a metal thin film 11 little by little, the plasma emitted light is constantly reflected by a fresh surface to which no material particles have adhered, thereby preventing a decrease in reflectance due to the adhesion of material substances. It becomes possible to do so.

Specific examples will be described below.

Specific Example When a PD film is formed by a sputtering method, the emission wavelength of PD is 250 nm. The observation light inlet was installed right next to the target. The diameter of the observation light introduction port was 2 mm, and the diameter of the observation light introduction tube was 30 mm. The metal thin film used was a 50 μm polyester film with 1000 Å of aluminum vapor-deposited, and was wound at a speed of 1 cm per minute. A condensing lens with f=150 was used. This method made it possible to clearly measure plasma emission intensity.

Specific Example PD was deposited by vapor deposition. In this case, a PD hollow cathode lamp was used as the light source. The structure shown in FIGS. 1 and 2 was also used on the light source side. By using the excitation emission intensity measurement device having the above structure on both the light emitting side and the light receiving side, measurement errors due to dirt on the observation window were completely eliminated.

Effects of the Invention As described above, according to the present invention, the observation window is not contaminated by material particles. Therefore,
For example, sputtering equipment, ion plating equipment, plasma etching equipment, plasma C, V,
When receiving light emitted from plasma in a device D or the like, it is possible to stably measure the emitted light intensity by installing the excitation emitted light intensity measuring device according to the present invention in the light receiving section. In addition, in cases where there is no self-luminescence, such as in a vapor deposition device, it is possible to stably measure the amount of light absorption by using a hollow cathode lamp or the like and installing the excitation emission intensity measuring device according to the present invention on the light emitting side and the light receiving side. Become.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of a main part of an excitation emission intensity measurement device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of the same main part, and FIGS. FIG. 3 is a vertical cross-sectional view of the main parts of the measuring device. 4... Light introduction tube for observation, 8... Film roll, 11... Metal thin film, 12... Winding motor.

Claims (1)

[Claims] 1. An observation light introduction tube that forms a substantially L-shaped observation light introduction path, and a metal that is arranged at a corner of the observation light introduction tube and has a good reflectance for the emission wavelength of the excited element. An excited emission intensity measuring device comprising a thin film and a winding means for winding up the metal thin film at a predetermined speed.