JPH04136175A - Thin film forming device - Google Patents

Abstract

PURPOSE:To prevent the generation of dust, etc., due to the reaction of the unreacted gas and to obviate the damage of a vacuum pump for an exhaust gas by forming a part of the exhaust pipe of the device for forming a thin film on a substrate by the reaction of the raw gas with a quartz tube provided with a heater. CONSTITUTION:Substrates 4 are placed on a substrate holder 5 and set in a reaction tube 3, the tube 3 is evacuated, gaseous SiH4 1 and gaseous N2O 2 are introduced, the substrate 4 is heated or plasma is produced in the tube 3, hence the raw gas enters into a reaction, and a thin film is formed on the substrate 4. In this case, the unreacted gas in the tube 3 is exhausted by a vacuum pump 9 through an exhaust pipe 6, introduced into an unreacted gas reaction chamber 10 from a gas inlet 11 and heated by a heater 13, hence the unreacted SiH4 and N2O undergo a reaction, and a film 15 is formed on a quartz sheet 14. Consequently, the concn. of the unreacted raw gas leaving an exhaust port 12 is reduced, and the generation of dust by the reaction at the other part of the exhaust pipe 6 is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application Invention 1 Relating to a thin film forming apparatus having a mechanism for introducing gas into a reaction chamber and exhausting gas from the reaction chamber Conventional technology Examples of conventional thin film forming apparatuses is shown in Figure 7. In the figure, 1 is an inlet for 5iH gas, which is a raw material gas required to cause a reaction and form a thin film, and 2 is an inlet for NtO gas, which is similarly used as a raw material gas 7). 3 is SiH
4 is a reaction tube for mixing gas and Neo gas and causing a reaction by heating, etc. 4 is a substrate on which a thin film is to be formed, and 5 is a substrate holder for fixing the substrate 4. , 6 is an exhaust pipe for exhausting the gas in the tube so as to keep the pressure and gas flow in the reaction tube 3 constant, and 7 is an exhaust pipe for introducing N2 gas to adjust the amount of exhaust by the exhaust pipe 6. 9 is a vacuum pump for evacuation.

In the conventional thin film forming apparatus configured as described above (
Above: The substrate 4 is arranged on the substrate holder 5, and the reaction tube 3 is placed in a vacuum state, and source gas is introduced from the aS i Ha gas inlet 1 and the Neo gas inlet 2.
In this state, the substrate 4 is heated or plasma is generated in the reaction tube 3 to cause a reaction of the source gas and form a thin film on the substrate 4. During this time, the unreacted gas in the reaction tube 3 is pumped up using a vacuum pump. 9 through the exhaust pipe 6 to keep the gas flow and pressure in the reaction tube 3 constant. In addition, the pressure inside the reaction tube 3 is controlled to a desired value by controlling the exhaust amount by the amount of N2 gas introduced from the balance N2 introduction lower. The gas exhausted through the exhaust pipe 6 contains a large amount of unreacted raw material gas, and a reaction naturally occurs within the exhaust pipe 6 to form the product 8. At this time, the exhaust pipe 6 is heated. If the product is not completely coated, it will not form a perfect film, but will float or adhere to the wall as a powder, or it will form a rough film and adhere to the wall, but these products will be removed due to backflow of nitrogen gas, etc. Blows into the reaction chamber 3 in the form of powder or film fragments that have peeled off from the wall surface.By directly adhering to the substrate 4 or once adhering to the inner wall of the reaction chamber 3 and then re-adhering to the substrate 4, defects in the thin film and the substrate may be caused. This may cause defects in the device formed on the top.
If the product enters the vacuum pump 9, 1
If a large amount of unreacted gas passes through the vacuum pump 9, it may cause the pump to malfunction.
If these unreacted gases are harmful, they must be removed using a toxic gas treatment device before being discharged into the atmosphere. Yes The conventional thin film forming apparatus has the above-mentioned problems such as the need to replace the poisonous gas treatment agent more frequently and the cost. It is an object of the present invention to provide a thin film forming device that prevents the generation of dust such as film fragments and does not cause deterioration of a vacuum pump and a toxic gas processing device.

Means for Solving the Problems The present invention includes a reaction chamber, a mechanism for introducing raw material gas into the reaction chamber, a mechanism for exhausting the gas in the reaction chamber from the reaction chamber, and a mechanism for removing unreacted gas from the exhaust gas. A thin film forming apparatus having a reaction chamber for forming a film by reacting gases is also a feature of the present invention. A quartz tube is used as a part of the evacuating mechanism, and a quartz tube is used as a part of the evacuating mechanism, and a quartz plate or the like is placed in a pipe made of quartz or a re-reaction chamber.

Effect of the present invention With the above-described configuration, the present invention accelerates the reaction by applying thermal energy or electrical energy from plasma to the unreacted gas, thereby reducing the amount of unreacted gas. The product does not become a powder or a coarse film, but forms a thin film that adheres to the wall surface, so no dust is generated. Embodiment (Example 1) FIG. 1 is a sectional view of a thin film forming apparatus shown in Embodiment 1 of the present invention. Raw material SiH
4 gas inlet, 2 is the raw material Neo
The gas inlet 3 is a reaction tube, in which a substrate holder 5 is installed, and the substrate 4 is placed on the holder.The reaction chamber is evacuated by a vacuum pump 9 through an exhaust pipe 6. A reaction chamber l in which unreacted gas is reacted in the middle of the exhaust pipe 6
As shown in Figure 2, a quartz plate 14 constitutes the wall surface of the unreacted gas reaction chamber 10 (see Figure 2). Even if it has a structure, the gas introduced into the unreacted gas reaction chamber 10 from the gas inlet 11 is heated by the heater 13 as an energy source for reacting the unreacted gas. According to
The unreacted 5iHa and NsO reacted and the quartz plate 14
By this, the concentration of unreacted raw material gas in the gas exiting from the exhaust port 12 is reduced, and it is possible to prevent it from reacting in other parts of the exhaust pipe 6 and becoming a source of dust. Although it is possible to extend the life of the exhaust gas treatment device by reducing the concentration of unreacted gas, the film 15 deposited in the unreacted gas reaction chamber 10 is removed from the heater 13.
Because the film is heated by 1 unreacted gas reaction chamber 10
Cleanliness can be easily maintained by removing and cleaning the entire body (Example 2) Fig. 3 shows a cross-sectional view of the unreacted gas reaction chamber 10 of the second embodiment of the present invention. ] 4 is quartz K for forming a film; 16 is an RF electrode that is an energy source for causing a reaction; The film I5 is deposited on the surface of the quartz plate 14. As a result, the concentration of unreacted gas in the gas exiting from the exhaust port 12 is reduced, and reactions at other locations can be prevented. By using an RF electrode, unreacted gas can be treated at low temperatures, and there is no need to consider thermal effects on other locations (C).
By using not only F discharge but also a heating structure, it is possible to more efficiently cause the unreacted gas to react, thereby making the formed film difficult to peel off (Example 3). FIG. 4 shows a sectional view of the inside of the unreacted gas reaction chamber of the third embodiment of the present invention. In the figure, I3 is a heater for heating unreacted gas, 14 is a quartz plate that becomes a substrate on which a film is formed, and 17 is an inlet for 02 gas. By introducing 02 gas, the oxidation of unreacted 5iHa gas is promoted and the unreacted gas is removed more efficiently.In this way, by introducing a gas that easily reacts with unreacted raw material gas. Unreacted gas can be removed even more efficiently (Example 4) Figure 5 shows a parallel plate plasma C shown in Example 4 of the present invention.
A is a cross-sectional view of the VD device. In the figure, 1 is the introduction μ of SiH4 and NHs gases, which are raw material gases, and 3 is the reaction i.
18 is an upper electrode for generating plasma;
19 is a lower electrode. Although the substrate 4 is placed on the lower electrode 19 and the inside of the reaction chamber 3 is evacuated by the vacuum pump 9 through the exhaust pipe 6, the apparatus shown in the figure uses the plasma generated by the upper electrode I8 and the lower electrode 19. Plasma CVD equipment for forming silicon nitride film
Even if unreacted gas such as 5iHJ is exhausted, an unreacted gas reaction chamber 1O is provided in the middle of the exhaust pipe 6 to remove unreacted gas from the exhaust gas and prevent dust from adhering to other walls. Prevents deterioration of adsorbent. In this way, similar effects can be obtained by providing a place where unreacted gas is reacted in various reaction systems other than CVD equipment using thermal reaction (Example 5). Figure 6 shows an example of the present invention. In the cross-sectional view of the thin film forming apparatus shown in 5, 13 is a heater, 14 is a quartz plate, and 20 is a quartz tube.
The plate, which was made in the US and had not been heated, reacted and adhered to the tube wall.In that case, dust was generated due to backflow of N2, etc., and the substrate inside the reaction chamber 4. Therefore, in this embodiment, a part of the exhaust pipe 6 is made into a quartz tube 20, and by heating it with a heater 13, the unreacted gas is deposited as a film with good adhesion on the wall of the quartz tube 2o. By providing the quartz plate 14 inside, the unreacted gas adheres as a film, which increases the removal efficiency of the unreacted gas.
In this embodiment, the same effect can be obtained by modifying a part of the exhaust pipe 6 without specifically providing a reaction chamber for unreacted gas as described above.

Effects of the Invention Invention 1: A reaction chamber, a mechanism for introducing raw material gas into the reaction chamber, a mechanism for exhausting the gas in the reaction chamber from the reaction chamber, and a mechanism for reacting unreacted gas in the exhaust gas. (a) A quartz tube should be used as part of the exhaust mechanism.

By having a mechanism for heating the quartz tube, the amount of untreated gas in the exhaust pipe is reduced, the generation of dust such as powder or film fragments is prevented, and a thin film forming device that does not degrade vacuum pumps and toxic gas processing equipment is provided. can also

[Brief explanation of drawings]

Fig. 1 is a sectional view of a thin film forming apparatus shown in Embodiment 1 of the present invention. Fig. 2 is a sectional view of an unreacted gas reaction chamber shown in Embodiment 1 of the present invention. Fig. 3 is shown in Embodiment 2 of the invention. FIG. 4 is a cross-sectional view of the unreacted gas reaction chamber according to the third embodiment of the present invention. FIG. 5 is a cross-sectional view of the parallel plate plasma CVD apparatus according to the fourth embodiment of the present invention. Figure 6 is a cross-sectional view of a thin film forming apparatus shown in Example 5 of the present invention. Figure 7 is a cross-sectional view of a conventional thin film forming apparatus.
3... Reaction tube, 4... Substrate, 5... Substrate holder, 6... Exhaust pipe, 9-... Vacuum pump, 1
0... Unreacted gas reaction i 13... Heater,
14...Quartz plate, 15...Sedimentary wind 16...R
F Den Kaede 17...02 Gas introduction n 18...Upper type [19...Lower electric photography 20...Quartz Kan agent's name Patent attorney Akira Okaji and 2 others Fig. Fig. Lead Fig. Rattan figure

Claims (4)

[Claims] (1) A reaction chamber, a mechanism for introducing a raw material gas into the reaction chamber, a mechanism for exhausting the gas in the reaction chamber from the reaction chamber, and forming a film by reacting unreacted gas in the exhaust gas. A thin film forming apparatus having a reaction chamber. (2) The thin film forming apparatus according to claim 1, wherein the reaction chamber for forming the film by reacting unreacted gas in the exhaust gas has a quartz plate and a heater inside. (3) The thin film forming apparatus according to claim 1, wherein the reaction chamber in which the film is formed by reacting unreacted gas in the exhaust gas forms a plasma state therein. (4) A reaction chamber, a mechanism for introducing raw material gas into the reaction chamber, and a mechanism for exhausting the gas in the reaction chamber from the reaction chamber, using a quartz tube as a part of the exhausting mechanism, A thin film forming apparatus characterized by having a mechanism for heating a quartz tube.