JPH05326417A - Apparatus for forming cvd thin film - Google Patents

Abstract

PURPOSE:To reduce the amount of particles which adhere to a semiconductor substrate when a thin film is deposited. CONSTITUTION:In a head 7 from which a reaction gas is blown off, a head cover 6 is evacuated. In addition, the outside of the head cover 6 is covered with an evacuation cover 3 and evacuated in the same manner. The lower part of a tray 12 on which a semiconductor substrate 2 conveyed from a semiconductor-substrate cassette 1 is placed and which is moved is evacuated. Respective evacuated gases are collected in one place, sucked by means of a fan 9 and connected to a chemical evacuation part 11. A particle counter 8 is connected to a tube so that particles inside the evacuation cover 3 can be monitored. Information at the particle counter 8 is sent to a computer 10. When the number of particles inside the evacuation cover 3 is increased, the fan 9 is adjusted by means of the computer 10 so that the number of particles is always the same inside the evacuation cover 3.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to CV in semiconductor manufacturing.
The present invention relates to a D thin film forming apparatus.

[0002]

2. Description of the Related Art In recent years, it has become more and more important to control particles in a device in semiconductor manufacturing.

An example of a conventional CVD thin film forming apparatus will be described below with reference to the drawings. FIG. 3 shows a conventional CV
It is a schematic diagram of a D thin film forming device. In FIG. 3, 1 is a semiconductor substrate cassette, 3 is an exhaust cover, 4 is an exhaust pipe, 5 is a depot chamber, 9 is a fan, 11 is an outlet for chemical exhaust, 13
Is an inverter and 14 is an exhaust pressure measurement point.

The operation of the CVD thin film forming apparatus having the above structure will be described below. The particles and gas generated in the exhaust cover 3 pass through the exhaust pipe 4 and the fan 9
Is exhausted to the chemical exhaust 11. Exhaust pipe 4
There is an exhaust pressure measurement point 14 on the way, and if there is a case where the exhaust pressure decreases at this point, a signal is sent, the inverter 13 adjusts the fan 9 to increase the exhaust amount, and the exhaust pressure measurement point must be set. The exhaust pressure is kept constant.

As another conventional technique, there is one in which a particle counter is attached in the thin film deposition portion (Japanese Patent Laid-Open No. 62-099470). This uses a particle counter for the purpose of controlling particles in the thin film deposition portion after the completion of thin film formation.

[0006]

However, in the above-mentioned structure, since the exhaust amount is adjusted only by the value of the exhaust pressure in the exhaust pipe, particles are generated during the thin film deposition more than the exhaust amount. In that case, there was a problem that the particles stayed in the exhaust cover.

In another conventional example, the exhaust control by the particle counter is not performed all the time but after the thin film formation is completed, and therefore it is impossible to prevent the particles generated during the thin film deposition from adhering to the semiconductor substrate.

The present invention solves such conventional problems,
Provided is a CVD thin film deposition apparatus having a function of keeping the number of particles in an exhaust cover constant during thin film deposition and controlling the number of particles deposited on a semiconductor substrate.

[0009]

In order to solve the above problems, a CVD thin film forming apparatus of the present invention comprises a deposition chamber, a thin film deposition unit in the deposition chamber for depositing a thin film on a semiconductor substrate, An exhaust device for exhausting particles in the thin film deposition part, a particle counter for measuring particles in the deposition part, and a computer for receiving a signal of the number of particles from the particle counter and controlling the exhaust device by the signal are provided. It is a thing.

[0010]

According to the present invention, even if a large amount of particles are generated when depositing a thin film, the present invention directly samples the particles in the exhaust cover and monitors the number of particles, so that the exhaust amount can be adjusted in real time. It is possible to maintain a constant number of particles.

FIG. 2 is a graph showing the correlation between the number of particles in the exhaust cover and the number of particles adhering to the semiconductor substrate. As can be seen from this graph, there is a strong correlation between the number of particles in the exhaust cover and the number of particles attached to the semiconductor substrate.

Therefore, according to the present invention, the number of particles adhering to the semiconductor substrate can be controlled by the constitution.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A CVD thin film forming apparatus according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view of a CVD thin film forming apparatus according to an embodiment of the present invention. In FIG. 1, 1 is a semiconductor substrate cassette, 2 is a semiconductor substrate, 3 is an exhaust cover, 4 is an exhaust pipe, 5 is a depot chamber, 6 is a head cover, 7 is a head, 8 is a particle counter, and 9 is an exhaust device. The fan, 10 is a computer, 11 is a chemical exhaust port, and 12 is a tray. A head cover 6 is attached to the outer side of the head 7, and the exhaust cover 3 covers the outer side where some of these heads 7 are lined up. From the exhaust cover 3 through the exhaust pipe 4, the fan 9 is connected to the chemical exhaust 11. Also, a tube is connected to the particle counter 8 through the exhaust cover 3,
The signal is fed back from the computer 10 to the fan 9.

The operation of the CVD thin film deposition apparatus configured as described above will be described below with reference to FIG.

The semiconductor substrate 2 contained in the semiconductor substrate cassette 1 is carried on a tray 12 and conveyed, and when it passes under the head 7, a reaction gas ejected from the head 7 causes a reaction to deposit a thin film. During the deposition of the thin film, the head cover 6 covering the outside of the head 7 is also evacuated, but most of the particles generated in the gas phase are not exhausted and remain in the exhaust cover 3. Therefore, although the inside of the exhaust cover 3 is also exhausted, the amount of particles generated varies depending on the reaction gas, the tray 12, and the state on the semiconductor substrate 2 flowing below. Therefore, when a larger amount of particles than usual is generated, the remaining amount that is not exhausted remains in the exhaust cover 3 or adheres to the semiconductor substrate 2. When depositing a thin film, the particle counter 8 monitors the amount of particles in the exhaust cover 3, and the signal is sent to the computer 1.
When the measured number of particles is equal to or smaller than a predetermined amount, the exhaust amount is not changed, and when the measured number is equal to or larger than the predetermined amount, the fan 9 is adjusted to increase the exhaust amount. By doing so, the inside of the exhaust cover 3 is always kept at a constant number of particles.

Here, the effect will be described again using the correlation graph between the number of particles in the exhaust cover and the number of particles on the semiconductor substrate in FIG. As the number of particles in the exhaust cover increases, the number of particles attached on the semiconductor substrate also increases, and the relationship is almost linear. Therefore, if the number of particles in the exhaust cover 3 is adjusted to be constant as in the embodiment of the present invention, the number of particles attached to the semiconductor substrate 2 can be controlled.

[0018]

As described above, according to the present invention, a particle counter is installed in the exhaust cover during thin film deposition, and if the signal from the particle counter is high, the exhaust amount in the exhaust cover is increased to control the exhaust amount in real time. By providing the function, the number of particles in the exhaust cover can be constantly controlled and the number of particles attached to the semiconductor substrate can be controlled.

[Brief description of drawings]

FIG. 1 is a schematic view of a CVD thin film deposition apparatus according to an embodiment of the present invention.

FIG. 2 is a diagram showing a correlation between the number of particles in an exhaust cover and the number of particles on a semiconductor substrate.

FIG. 3 is a schematic view of a conventional CVD thin film deposition apparatus.

[Explanation of symbols]

 1 Semiconductor Substrate Cassette 2 Semiconductor Substrate 3 Exhaust Cover 4 Exhaust Pipe 5 Depot Chamber 6 Head Cover 7 Head 8 Particle Counter 9 Fan 10 Computer 11 Chemical Exhaust 12 Tray 13 Inverter 14 Exhaust Pressure Measurement Point

Claims (1)

[Claims] 1. A deposition chamber, a thin film deposition unit in the deposition chamber for depositing a thin film on a semiconductor substrate, an exhaust device for exhausting particles in the thin film deposition unit, and measuring particles in the deposition unit. A CVD thin film forming apparatus comprising: a particle counter and a computer that receives a signal of the number of particles from the particle counter and controls the exhaust device by the signal.