JPS62130279A - Plasma cvd apparatus - Google Patents

Abstract

PURPOSE:To converge electron along a barrel-shaped magnetic field and to make electron density high density without changing electronic energy distribution by forming the barrel-shaped magnetic field coordination by a magnetic field generating means. CONSTITUTION:Both an anodic electrode 3 and a cathodic electrode 4 are oppo sitely provided and a ring-shaped electromagnet 8 is provided while biting a little spherical part between both electrodes 3, 4 and an electromagnet 9 having same shape as it is provided to an under side of the cathode electrode 4. When connecting these to a DC electric power source 10, a magnetic field is formed as a barrel-shaped magnetic field coordination. Therefore electron generated in a bulgy part A of the barrel-shaped magnetic field is shifted to a recess part B side in accordance with the lines of magnetic force. At this time, since the lines of magnetic force are converged, electron density is made large in the part B and ionization, dissociation and excitation are effectively caused.

Description

[Detailed description of the invention] Technical field The present invention relates to a plasma CVD apparatus.

Conventional technology In general, plasma CVD equipment is a-5 for life-size optical sensors.
It is used as an effective method for producing large area thin films such as i:H large area thin films and thin film transistors (TPT).

FIG. 4 shows a conventional standard plasma CVD apparatus. First, a substrate 2 is placed in the chamber 1 while being supported by an anode electrode 3, and a cathode electrode 4 is provided facing the substrate 2. A high frequency wave from a high frequency power source 5 is applied between the cathode electrode 4 and the anode electrode 3 via a matching circuit 6 and a blocking capacitor 7. As a result, discharge occurs at both electrodes 3.
- Occurs within 1 hour. Then, a cathode drop of ~100 V occurs near the cathode electrode 4, a negative glow portion occurs above it, and an anode dark portion occurs near the anode electrode 3. Here, ionization of the supplied gas occurs in a portion of this negative glow due to electrons accelerated from the vicinity of the cathode electrode 4 and electrons captured within the negative glow by the high frequency electric field. The electrons and ions generated in this negative glow part move toward the electrode and also move toward the wall perpendicular to the electric field due to bipolar diffusion. For this reason, the efficiency of dissociation and excitation of the supplied gas by the generated ions and electrons is reduced. Therefore, the film formation rate is slow. In other words, conventionally, the ionization state inside the chamber is controlled by controlling the supply gas flow rate, pressure, power supply, device shape, etc., but it is important to increase the deposition rate without deteriorating the film properties. Have difficulty.

In this regard, the conventional idea of preventing diffusion by applying a magnetic field parallel to the electrode direction has been changed, for example, by rJournal.
of Non-Crystalline
5olids35&36 (1980) 189
-194J etc. have been attempted.

Purpose The present invention was made in view of the above points, and an object thereof is to obtain a plasma CVD apparatus that can further improve the density of electrons and improve the efficiency of ionization, dissociation, and excitation. .

Structure In order to achieve the above object, the present invention arranges an anode electrode and a cathode electrode in parallel to face each other, and provides magnetic field generating means for forming a barrel-shaped magnetic field configuration parallel to the direction of these electrodes. It is characterized by capturing and converging electrons by magnetic field coordination to generate a discharge with high electron density.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. The same parts as those shown in FIG. 4 will be explained using the same reference numerals. In this embodiment, a ring-shaped electromagnet 8 is provided that is slightly wedged into the periphery between the electrodes 3 and 4, and an electromagnet 9 having the same shape as this electromagnet 8 is provided below the cathode electrode 4 to generate these magnetic fields. An electromagnet 8.9 as a means is connected to a DC power source 10. Such electromagnets 8, 9 generate a magnetic field as shown in FIG. Such a magnetic field is formed as a so-called barrel-shaped magnetic field configuration.

As a result of (2), the electrons generated in the bulge A of the barrel-shaped magnetic field move toward the concave portion B according to the lines of magnetic force.

At this time, the lines of magnetic force converge, so the electron density increases in part B, and ionization, dissociation, and excitation occur more effectively than in the absence of such a magnetic field.

Since the dissociated molecules and radicals are electrically neutral, they are carried as they are onto the substrate 2 along the flow of neutral particles.

In this case, the magnetic field to be generated by the electromagnets 8 and 9 is
The mean free path of neutral particle collision, rL, is the electron Larme
When the radius is r, it is necessary to set λ/rt, >1. The magnetic field that satisfies this is ~1K Gauss in the central part of region B.

Figure 3 shows the film formation speed at the center of the substrate 2, which is expressed as a ratio of 1 by the strength of the magnetic field.
It is one crossing. According to this, although a film formation rate about twice as high can be obtained with the BoO force, the uniformity of the film deteriorates when the magnetic field strength is greater than this.

Effects In the present invention, as described above, a barrel-shaped magnetic field configuration is formed by the magnetic field generating means, so that electrons can be focused along this magnetic field, and the electron density can be increased without changing the electron energy distribution. Therefore, the film formation rate can be improved.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram of magnetic field line distribution showing one embodiment of the present invention.
FIG. 2 is a schematic front view of the entire apparatus, FIG. 3 is a characteristic diagram of film forming speed, and FIG. 4 is a schematic front view showing a conventional example. 3... Anode electrode, 4... Cathode rfE N,
8,9...Electromagnet (magnetic field generating means) 3 J [3 57Figure 33Figure 3 is a diagram

Claims (1)

[Claims] An anode electrode and a cathode electrode are arranged facing each other in parallel, and a magnetic field generating means is provided to form a barrel-shaped magnetic field configuration parallel to the direction of these electrodes, and this barrel-shaped magnetic field configuration captures and converges electrons to generate a high A plasma CVD apparatus characterized by performing electron density discharge.