JPH0355552B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a plasma reactor and a method of using the same. More specifically, in the production of solid-state devices, etc., plasma is characterized by forming a plasma vapor-deposited film on any substrate, causing a plasma reaction between the substrate surface and an introduced gas, or plasma etching the substrate surface. A reactor is provided.

Conventional configurations and their problems Conventionally, many types of CVD equipment have been manufactured.
Two typical examples are shown in FIG.

Fig. 1a shows a horizontal CVD device, which consists of a gas inlet 1, a high-frequency coil 2, a reaction tube 3, an exhaust port 4, a heater 5, and an exhaust port 6.The heater 5 is tilted with respect to the gas flow. It is made so that the CVD films on the plurality of substrates 6 are uniformly applied. However, in this device, although there is little variation in the CVD film within the substrates 6, among the plurality of substrates 6, the film closer to the gas inlet 1 is thicker and the film closer to the exhaust port 4 is thinner. Furthermore, since the heater and the substrate are brought into close contact with each other and the substrate is heated by thermal conduction, if the substrate is bent, temperature unevenness will occur within the substrate, resulting in uneven CVD films.

Figure 1b shows a C-coupled plasma CVD apparatus, which includes a gas inlet 11, a high-frequency electrode 12, and a reaction chamber 1.
3, an exhaust port 14, and a heater 15, and a plurality of substrates 1 are placed on the heater 15 via a susceptor 16.
7 and rotate the susceptor 16 to reduce variations between substrates and improve the drawbacks of the horizontal type.

However, in both methods, because the substrate faces upward, the same reactants (e.g. SiO _{2 ) formed by reactions in the dust and gas that cause pinholes in the CVD film and the same reactants (e.g. SiO 2} ) The disadvantage is that SiO2 particles (formed by SiO ₂ particles) tend to fall and adhere to the surface, which is an obstacle to uniform CVD film formation.

Further, no consideration was given to automation in the placement of the substrates, and since each substrate was placed by hand, there were many cases where the substrates were damaged or dropped.

Purpose of the Invention In view of these problems, the present invention aims to provide a plasma reaction apparatus that can reduce dust on a substrate as much as possible, uniformly and automatically place the substrate, and furthermore, uses the same configuration. plasma
It is an object of the present invention to provide a plasma reaction device that can be used as a CVD device, a plasma oxidation or nitride film forming device, or a plasma etching device, and a method for using the same.

Structure of the Invention In the present invention, a reaction tube equipped with a reaction gas inlet, a plasma generation part, an exhaust port, and a substrate insertion port is installed vertically, and a heater is installed as a heating source outside the reaction tube. A capacitive electrode or coil is installed above the outside of the reaction tube for plasma generation, and multiple substrates with horizontal main surfaces can be placed vertically inside the reaction tube, and they can be taken in and out of the reaction tube from below. The reaction gas inlet is provided at the upper part of the reaction tube, and the exhaust port is provided at the lower part of the reaction tube. Preferably, the holding part is rotatable during the plasma reaction. Furthermore, the present invention provides a plasma reactor characterized by a structure in which a holding part on which a substrate is placed can be inserted so that the surface thereof faces downward while the gas flow inside the reaction tube is directed downward, and a method for using the same. This is what we provide.

DESCRIPTION OF EMBODIMENTS An apparatus according to one embodiment will be described below with reference to the drawings.

FIG. 2 shows a sectional view of a plasma reactor according to an embodiment of the present invention. This device includes a reaction gas inlet 21, a plasma generation section 22, an exhaust port 23,
Heat-resistant packing 24, cooling water pipe 25, furnace body 26, reaction tube 27, resistance heater 28, substrate holding part 29,
A carrier 3 consisting of a board insertion port cover 30 and with a plurality of boards 31 set with their intended surfaces facing downward.
2 can be inserted from the bottom. After fixing the carrier 32, the exhaust port 23 is evacuated to create a vacuum, and the evacuation is continued while introducing the reaction gas from the reaction gas inlet 21. While maintaining a constant state of reduced pressure, the high frequency coil 33 generates plasma. This structure generates plasma to form a plasma CVD film on the surface of the substrate 31, causes the substrate surface to react with the introduced gas, and etches the substrate surface. Note that at this time, the substrate temperature is controlled by the heater 28.

When performing plasma CVD using this device,
For example, when depositing Si ₃ N ₄ on a substrate,
A mixed gas such as SiH ₂ Cl ₂ , NH ₃ , Ar, etc. may be used, and if the substrate is Si, a mixed gas such as O ₂ , Ar, etc. may be used when performing a reaction with the introduced gas, such as oxidation or titanization. to form SiO, NH ₃ , Ar
etc. can be used to form Si ₃ N ₄ . Furthermore, when etching the substrate,
Si can be etched as SiF ₄ using SF ₆ or the like.

In addition, in the plasma reaction apparatus shown in this example,
By rotating the substrate holder 29 during the plasma reaction, variations within the substrate can be made more uniform. In addition, when inserting the substrate, the gas flow inside the reaction tube is directed downwards, and by inserting the holder with the substrate on it so that the surface is facing downward, dust and foreign matter can be prevented from adhering to the substrate surface. can be prevented. Furthermore, by performing plasma etching without inserting a substrate, it is also possible to clean the inner wall of the reactor core tube without removing the reactor core tube.

In addition, in FIG. 2, 34 is a pyrometer, 35 is a gas supply device, 36 is a mechanical booster pump, 37 is a rotary pump, 38 is a loader, 3
Reference numeral 9 indicates a viewing window, arrow A indicates rotation of the substrate holder, and arrow B indicates the reaction gas flow. Moreover, FIG. 2 shows a case where the furnace body 26 is erected almost perpendicularly to the ground.

Effects of the Invention According to this apparatus, (1) Since the inside of the reaction tube 27 is in a reduced pressure state and the target surface of the substrate 31 can be set downward, dust is less likely to adhere to the target substrate surface during the reaction.

(2) When inserting the carrier 32, air flows downward, so dust does not fly up.

(3) Since the substrate 31 is heated by the radiant heat of the reaction tube 27, there is little variation in temperature within the substrate 31 and between the substrates 31, and the uniformity of the plasma reaction is good.

(4) The board 31 can be placed on the carrier 32 automatically.

(5) Since the plasma generating section 22 is located away from the substrate and ionized particles do not directly collide with the surface of the substrate, damage caused by positive ions or electrons can be reduced even when the substrate is a semiconductor element.

(6) Cleaning the inner wall of the core tube is extremely easy.

(7) Since the reaction gas introduction part and the plasma generation part are provided at the top, gas convection inside the reaction tube can be reduced and a uniform discharge state can be obtained, and a large amount of substrates can be taken out and inserted from the bottom of the reaction tube. It is easy to perform and is ideal for automation and mass production.

Demonstrates excellent effects such as

Although the examples show the case where the reaction tube is vertical, the same effect can be obtained even when the reaction tube is tilted.

As described above, the plasma reaction device of the present invention prevents dust from adhering to the substrate as much as possible and has a uniform thickness.
It is possible to form a CVD film, to form an oxide film or a silicon oxide film, and to perform etching.

Furthermore, it is a device that can be fully automated from inserting the substrate to taking out the plasma reaction.

In addition, it is also possible to perform a plasma reaction while applying a stronger magnetic field to the outside of the furnace body of this apparatus so as to be parallel to the substrate surface, and to improve the film quality by the cyclotron movement of electrons. Furthermore, it is also possible to add a grid electrode as shown at 40 in FIG. 2 to introduce only excitons to the substrate side.

[Brief explanation of drawings]

Figure 1a shows the horizontal type that has been used conventionally.
A schematic diagram of a CVD device, FIG. 1b is a schematic diagram of the same vertical CVD device, and FIG. 2 is a schematic diagram of an embodiment of the present invention.
FIG. 2 is a cross-sectional view of the structure of the CVD device. 21... Reaction gas inlet, 22... Plasma generation part, 23... Exhaust port, 26... Furnace body, 27...
Reaction tube, 29...Substrate holder, 31...Substrate, 3
2...Carrier, 30...Board insertion port plug.

Claims (1)

[Scope of Claims] 1. A reaction tube is installed vertically and is heated by an external heating source and is equipped with a reaction gas inlet, a plasma generation section, an exhaust port, and a substrate insertion port, and above the outside of the reaction tube is the A holding part in which a plasma generation electrode or coil is installed, a plurality of substantially horizontal substrates with their main surfaces facing downward can be placed vertically inside the reaction tube, and the holding part can be inserted into and taken out from below inside the reaction tube. A plasma reaction apparatus comprising: the reaction gas inlet port provided at the top of the reaction tube, and the exhaust port provided at the bottom of the reaction tube. 2. The plasma reaction apparatus according to claim 1, wherein the holding part is rotatable from outside the reaction tube. 3. A step of vertically placing a plurality of substantially horizontal substrates with their main surfaces facing downward on a holding part, and a step of inserting the holding part on which the substrates are placed from below into an erected reaction tube; After exhausting the gas inside the reaction tube from the exhaust port at the bottom of the reaction tube, the reaction gas is introduced from above the reaction tube while continuing to exhaust the reaction tube, and a high-frequency electric field is generated above the outside of the reaction tube under a constant pressure. 1. A method of using a plasma reactor, which comprises applying plasma to generate plasma to form a plasma vapor-deposited film on the surface of the substrate, to cause a plasma reaction between the surface of the substrate and the introduced gas, or to perform plasma etching.