JPH04107917A - Reduced pressure treatment apparatus for semiconductor substrate - Google Patents

Abstract

PURPOSE:To see that the dust such as reactant, etc., does not flow back from an exhaust pipe to a chamber by providing a trap between a chamber and a gate valve, and projecting fins alternately in the direction of the center from the inwalls on both sides of a barrel, and inclining the fins in the direction of the downstream side of the substrate flowing in the barrel while overlapping them. CONSTITUTION:A trap 7, which prevents the reverse flow of dust, comprises a cylindrical barrel 71 and plural pieces of semicircular fins 72 provided inside the barrel 71. And the tips of fins 72, which are projecting alternately in the direction of the center from the inwalls on both sides of the barrel 71, are overlapped with each other at the center of the barrel 71, and the fins 72 are inclined in the direction of the downstream side of the gas flowing inside the barrel 71. Putting it in this constitution, when the pressure inside the chamber is reduced, the reactants are exhausted out of the exhaust pipe together with the substrate, but when returning the inside of the chamber to normal pressure, the reactants are intercepted by the fins, and do not flow in the chamber.

Description

[Detailed Description of the Invention] [Summary] Regarding the reduced pressure processing equipment for semiconductor substrates, especially the low pressure CVD equipment, dust such as reactants that inhibit the normal processing of semiconductor substrates,
The purpose of this device is to provide a decompression processing device that prevents backflow of dust from the exhaust system piping to the chamber.It consists of a cylindrical body and multiple fins installed inside the body, and a trap to prevent dust from flowing back into the chamber and gate valve. The tips of the fins provided between the body parts and protruding alternately from both inner walls of the body part toward the center are connected to the body part 71.
The fins overlap each other in the center, and the fins are configured to be inclined in the downstream direction of the gas flowing inside the body.

[Industrial application field]

The present invention relates to a reduced-pressure processing apparatus for semiconductor substrates, and particularly to a low-pressure CVD apparatus (low-pressure chemical vapor deposition apparatus).

As a means of forming various thin films on semiconductor substrates in the manufacture of semiconductor devices, a low-pressure CVD method is used to lower the pressure inside a chamber in which the semiconductor substrate is housed, feed a reactive gas, and form thin films through chemical changes in the reactive gas at high temperatures. is used.

However, in low-pressure CVD apparatuses that form thin films through chemical changes in reactive gases, powder-like reactants are generated in locations other than the semiconductor substrate, and if such reactants adhere to the semiconductor substrate, it may cause defects. That is, the low-pressure CVD apparatus must be able to easily remove reactants adhering to the inside of the chamber, exhaust system piping, etc., and must not allow the reactants to flow back into the chamber from the exhaust system piping, etc.

[Conventional technology]

FIG. 2 is a schematic diagram showing the main parts of a conventional low-pressure CVD apparatus.

In the figure, a conventional low-pressure CVD apparatus has a chamber 2 that houses a semiconductor substrate 1, and a pump 3 that decompresses the inside of the chamber 2, which are connected in series via a gate valve 4, and are used to assist in finely adjusting the exhaust volume. Valve 5 is gate valve 4
A switching valve 6 is connected in parallel with the gate valve 4 and opens on the upstream side of the gate valve 4 for returning the inside of the chamber 2 to normal pressure.

When the semiconductor substrate 1 is placed inside the chamber 2, the lid (not shown) is closed, and the pump 3 is activated and the gate valve 4 or the auxiliary valve 5 is opened, the inside of the chamber 2 is depressurized and the chamber 2 is opened from the opposite side. Reactant gas is pumped into the chamber. Further, when the gate valve 4 and the auxiliary valve 5 are closed and the switching valve 6 is opened, nitrogen gas or the like flows in through the switching valve 6, and the inside of the chamber 2 returns to normal pressure.

[Problem to be solved by the invention]

However, in the case of low-pressure CVD equipment that forms thin films through chemical changes in reactant gases, powder-like reactants are generated in places other than the semiconductor substrate, and when the pressure inside the chamber is reduced, the reactants are mixed with gases in the exhaust system piping. , for example, flows into valves such as gate valves, auxiliary valves, switching valves, etc., and pipes connecting the chamber and these valves, and is deposited thereon. When the pressure inside the chamber is returned to normal pressure, the reactants flow into the chamber together with nitrogen gas and the like. That is, there is a problem in that the generated reactants travel back and forth within the chamber and the exhaust system piping, and as the process is repeated, the amount increases and adheres to the semiconductor substrate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a reduced pressure processing apparatus in which dust such as reactants that inhibit normal processing of semiconductor substrates does not flow back into the chamber from the exhaust system piping.

[Means to solve the problem]

FIG. 1 is a schematic diagram showing a reduced pressure processing apparatus according to the present invention. The same objects are represented by the same symbols throughout the figures.

The above problem is a depressurization processing device in which a chamber 2 and a pump 3 for depressurizing the inside of the chamber 2 are connected in series via a gate valve 4. A trap 7 that prevents backflow of dust is provided between the chamber 2 and the gate valve 4, and the tips of the fins 72 are formed by protruding alternately from both inner walls of the body part 71 toward the center. , body part 7
overlap each other in the center of 1, and
This is achieved by the depressurization processing apparatus for semiconductor substrates of the present invention in which the fins 72 are inclined in the downstream direction of the gas flowing inside the body portion 71.

[For production]

In Fig. 1, the trap is made up of a cylindrical body and a plurality of fins installed inside the body, and a trap is provided between the chamber and the gate valve to prevent dust from flowing backwards, and a trap is provided between the chamber and the gate valve, extending from the inner walls of both sides of the body toward the center. The depressurization processing device of the present invention has tips of alternately protruding fins that overlap each other at the center of the body, and the fins are inclined in the downstream direction of the gas flowing inside the body. At this time, the reactants are discharged together with the gas into the exhaust system piping, but when the pressure inside the chamber is returned to normal pressure, the reactants are blocked by the fins and do not flow into the chamber. That is, it is possible to realize a reduced pressure processing apparatus in which dust such as reactants that inhibit normal processing of semiconductor substrates does not flow back into the chamber from the exhaust system piping.

〔Example〕

Embodiments of the present invention will be described in more detail below with reference to FIG.

In the figure, a reduced pressure processing apparatus according to the present invention, for example, a low pressure CV
In device D, a chamber 2 and a pump 3 are connected in series via a gate valve 4, and the chamber 2 and the gate valve 4 are connected in series.
A trap 7 is removably provided between them. An auxiliary valve 5 for finely adjusting the exhaust amount is connected in parallel with the gate valve 4, and a switching valve 6 for returning the inside of the chamber 2 to normal pressure is open between the gate valve 4 and the trap 7.

The trap 7 that prevents backflow of dust has a cylindrical body part 71
The tips of the fins 72, which are made up of a plurality of semicircular fins 72 provided inside the body part 7I and alternately protrude from both inner walls of the body part 71 toward the center, are connected to the body part 71.
The fins 72 overlap each other at the center, and the fins 72 are inclined in the downstream direction of the gas flowing inside the body part 71.

The semiconductor substrate l is placed inside the chamber 2, the lid (not shown) is closed, the pump 3 is activated, and the gate valve 4 and the auxiliary valve 5 are opened. A reactant gas is fed into the chamber 2. At this time, reactants flow into the exhaust system piping together with the gas via the trap 7 and are deposited therein.

In addition, gate valve 4 and auxiliary valve 5 are closed and switching valve 6 is closed.
When opened, nitrogen gas or the like flows in through the switching valve 6, and the inside of the chamber 2 returns to normal pressure. At this time, reactants deposited in the exhaust system piping try to flow into the chamber 2, but unlike gas, such reactants have the property of moving along the wall surface and flow through the fins 72 inside the body section 71. Since the gas is inclined in the downstream direction, the movement of reactants is blocked by the trap 7 and cannot flow into the chamber 2.

In this way, it consists of a cylindrical body and a plurality of fins installed inside the body, and a trap to prevent backflow of dust is provided between the chamber and the gate valve, and the traps are arranged alternately from the inner walls on both sides of the body toward the center. The tip of the fin that protrudes from
In the depressurization treatment apparatus of the present invention, in which the fins overlap each other in the center of the body part and are inclined in the downstream direction of the gas flowing inside the body part, when the pressure inside the chamber is reduced, the reactant is removed from the exhaust system piping together with the gas. However, when the inside of the chamber is returned to normal pressure, the reactants are blocked by the fins and do not flow into the chamber.

That is, it is possible to realize a reduced pressure processing apparatus in which dust such as reactants that inhibit normal processing of semiconductor substrates does not flow back into the chamber from the exhaust system piping.

It should be noted that in conventional depressurization processing equipment, such as low-pressure CVD equipment, it was necessary to periodically interrupt the process and clean not only the inside of the chamber but also the inside of the exhaust system piping including the valve, but with the depressurization of the present invention, In the case of processing equipment, processing can be restarted simply by replacing the trap, and traps in which reactants have accumulated can be cleaned during processing. That is, it is possible to shorten the stop time of the decompression processing apparatus and increase the operating rate.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a reduced pressure processing apparatus in which dust such as reactants that inhibit normal processing of semiconductor substrates does not flow back into the chamber from the exhaust system piping.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a reduced pressure processing apparatus according to the present invention. FIG. 2 is a schematic diagram showing the main parts of a conventional low pressure CVD apparatus. In the figure, 1 is a semiconductor substrate, 2 is a chamber, 3 is a pump,
4 is a gate valve, 5 is an auxiliary valve, 6
7 represents a switching valve, 7 represents a trap, 71 represents a body portion, and 72 represents a fin.

Claims (1)

[Claims] A depressurization processing apparatus comprising a chamber (2) and a pump (3) for decompressing the inside of the chamber (2), which are connected in series via a gate valve (4). body part (7
1) and a plurality of fins (72) provided inside the body portion (71), the trap (72) prevents backflow of dust.
7) is provided between the chamber (2) and the gate valve (4), and the tips of the fins (72), which are alternately protruded from both inner walls of the body part (71) toward the center, are connected to the body part (71). Department (71
) overlap each other in the center, and
A reduced pressure processing apparatus for semiconductor substrates, characterized in that the fins (72) are inclined in the downstream direction of the gas flowing inside the body (71).