KR20000009190A - Chemical vapor deposition apparatus - Google Patents

Abstract

PURPOSE: A chemical vapor deposition apparatus capable of depositing a thin film on a wafer loaded on a boat in a uniform thickness by making uniform a flow of a reactive gas in an inner pipe is provided. CONSTITUTION: The chemical vapor deposition apparatus comprising: a boat(150), a plurality of wafers are loaded in an inside of the boat(150); a double reaction pipe(110) including a inner pipe(112) for enclosing the boat(150) and an outer pipe(114) arranged at an outer side of the inner pipe(112); a heating source(120) arranged at an outer side of the outer pipe(114) of the double reaction pipe(110) for heating the double reaction pipe(110); a gas supply pipe(130) for supplying reactive gas into the inner pipe(112) of the double reaction pipe(110); and a gas discharge pipe(140) installed between the inner pipe(112) and outer pipe(114) for discharging the reactive gas to an outside of the double reaction pipe(110).

Description

Apparatus for chemical vapor deposition (CVD)

The present invention relates to a chemical vapor deposition apparatus, and more particularly, to a chemical vapor deposition apparatus capable of forming a thin film of a constant thickness on a wafer by uniformly flowing the reaction gas in the inner tube.

In the semiconductor manufacturing process, a deposition process is a kind of material synthesis that obtains a thin film required by solidifying a specific atom or molecule from a source of a gas or vapor phase. (Material Synthesis) process. To manufacture semiconductor devices, various kinds of metal or silicide thin films, such as poly-crystal silicon, oxide film, and nitride film, are required. All of these thin films are formed by a deposition process. .

The deposition process may be referred to as a thin film process, which is roughly classified into a physical vapor deposition (PVD) process and a chemical vapor deposition (CVD) process. The PVD process is deposited only through the conversion of phases without adding or subtracting other components from the source. On the other hand, because CVD processes involve chemical reactions, there is a difference in physicochemical structure between the source and the deposition product.

The CVD process supplies a gas (or vapor) source and a reactant gas containing an element of a target material to be deposited onto a substrate such as a heated wafer, and causes a chemical reaction to form a solid thin film on the substrate and a reaction by-product ( By-product) A series of processes to remove gases. The CVD process may be classified into atmospheric CVD and low pressure CVD processes according to the deposition pressure, or may be classified into thermal CVD, plasma CVD, optical CVD, and laser CVD processes according to energy sources.

Here, the low pressure CVD process is a process of depositing a thin film on the wafer surface of the reacted gas compound by reacting the gas in a vacuum state. The reaction tube of the device used in the low pressure CVD process is a double reaction tube composed of an inner tube and an outer tube made of quartz (SiO ₂ ), and a deposition process is performed in the inner tube.

Hereinafter, a CVD apparatus used for a low pressure CVD process according to the prior art will be described with reference to the accompanying drawings.

Referring to FIG. 1, a vertical CVD apparatus 100 according to the related art is described. The CVD apparatus 100 includes a gas supply pipe 30 through which a reaction gas is supplied, and a double reaction tube 10 connected to the gas supply pipe 30. ), A heating source 20 for heating the double reaction tube 10, a gas discharge tube 40 and a double reaction tube 10 for discharging the exhaust gas containing the reacted remaining reaction gas and unreacted by-products. Including a boat (50) installed in the inside, the bottom portion of the boat 50 has a structure that is stored on the axis of rotation (70). Here, the boat 50 is a means which can load the some wafer 60.

The dual reaction tube 10 is composed of an inner tube 12 and an outer tube 14, which are quartz reaction tubes, and a boat 50 in which a plurality of wafers 60 are vertically stacked is installed inside the inner tube 12. The bottom part of 50 is supported by the rotating shaft 70. In addition, the upper portion of the inner tube 12 is open so that the reaction gas injected into the inner tube 12 deposits a thin film on the wafer 60 installed in the inner tube 12, and the exhaust gas is formed on the upper portion of the inner tube 12. It is discharged to the gas discharge pipe 40 through the exterior 14 via the opening 16. The boat 50 is also made of quartz. Typically, the diameter of the opening 16 is larger than the diameter of the boat 50 so that the exhaust gas can be discharged well through the opening 16 of the inner tube.

The gas supply pipe 30 to which the reaction gas is supplied is connected to the inside of the inner pipe 12 and is installed in parallel with the side surface of the inside of the inner pipe 12. The gas supply pipe 30 has a short length and is provided near the bottom of the boat 50. The reaction gas is supplied upwards from the upper portion of the gas supply pipe 30, and the exhaust gas containing the reaction gas passing through the wafer 60 is discharged to the opening 16 located above the inner tube 12, and the inner tube ( It is discharged through the gas discharge pipe 40 connected between 12 and the appearance (14).

In the CVD process using the CVD apparatus 100 having such a structure, the reaction gas is supplied through the gas supply pipe 30 in a state in which the rotating shaft 70 on which the boat 50 is stored is rotated at a predetermined speed so that the wafer ( Deposition of the necessary thin film on 60), and proceeds to the step of discharging the exhaust gas containing the reaction gas remaining in the reaction through the gas discharge pipe (40) out of the double reaction pipe (10).

By using such a vertical CVD apparatus, the processing capacity of about 10 times can be improved as compared with the conventional CVD apparatus. On the other hand, the vertical CVD apparatus was initially deposited without rotating the boat, but in order to deposit a uniform thin film on the wafer, the deposition process was performed while rotating the boat in one direction.

However, in such a vertical CVD apparatus 100, since the diameter of the opening 16 of the inner tube is larger than the diameter of the boat 50, the time when the reaction gas is stagnated in the wafer 60 loaded on the boat 50 is fixed. This is short. Since most of the reaction gas supplied to the inner tube 12 passes through the opening 16 of the inner tube through the space between the boat 50 and the inner tube 12 and is discharged to the outer surface 14, the inner tube 12 The thickness of the thin film formed in the central portion of the wafer 60 close to the center of the boat 50 is relatively thin as compared to the edge of the wafer 60 close to). That is, since the flow of the reaction gas supplied to the inner tube 12 is not uniform, the thickness of the thin film formed on the wafer 60 becomes thinner from the edge to the central portion.

Accordingly, an object of the present invention is to provide a chemical vapor deposition apparatus capable of depositing a thin film with a constant thickness on a wafer loaded in a boat by making the flow of reaction gas uniform in the inner tube.

1 is a partial cross-sectional view showing a chemical vapor deposition apparatus using a double reaction tube according to the prior art,

2 is a partial cross-sectional view showing a chemical vapor deposition apparatus using a double reaction tube according to an embodiment of the present invention.

Description of the main parts of the drawing

110: double reaction tube 112: inner tube

114: appearance 116: opening

118: gas outlet 120: heating source

130: gas supply pipe 140: gas discharge pipe

150: boat 160: wafer

200: chemical vapor deposition apparatus

In order to achieve the above object, the chemical vapor deposition apparatus according to the present invention includes a boat having a plurality of wafers loaded therein; A double reaction tube composed of an inner tube surrounding the boat and an exterior disposed outside the inner tube; A heating source disposed outside the exterior; A gas supply pipe for supplying a reaction gas to the inner pipe; And a gas discharge tube installed between the inner tube and the outer tube and discharging the reaction gas out of the double reaction tube. In particular, in the chemical vapor deposition apparatus according to the present invention, an opening smaller than the diameter of the boat is formed in the upper portion of the inner tube to uniformly flow the reaction gas in the inner tube, and the inner wall of the inner tube has a predetermined interval. A plurality of gas outlets are formed in the direction in which the wafer is loaded.

The gas outlet formed in the inner tube according to the present invention is preferably formed on the opposite side where the gas supply pipe is installed so that the reaction gas supplied through the gas supply pipe can be uniformly supplied between the wafers loaded on the boat.

The gas outlet formed in the inner tube according to the present invention is preferably formed toward the place where the gas discharge pipe is installed so that the reaction gas can be stably discharged through the gas discharge pipe.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention.

2 is a partial cross-sectional view showing a CVD apparatus 200 using a double reaction tube according to an embodiment of the present invention. Referring to FIG. 2, the CVD apparatus 200 is disposed outside the gas supply pipe 130 into which the reaction gas is injected, the double reaction pipe 110 connected to the gas supply pipe 130, and the double reaction pipe 110. A heating source 120 for heating the double reaction tube 110, a gas discharge tube 140 for discharging the remaining residual gas and unreacted by-products, and a boat 150 installed inside the double reaction tube 110. It includes, the bottom portion of the boat 150 has a structure (축) (축) is stored on the rotating shaft (170).

The double reaction tube 110 is a quartz reaction tube, and includes an inner tube 112 surrounding a boat and an outer side 114 disposed outside the inner tube 112. Inside the inner tube 112, a boat 150 in which a plurality of wafers 160 are stacked is installed, and a bottom portion of the boat 150 is supported on the rotation shaft 170. The upper portion of the inner tube 112 is open so that the reaction gas injected into the inner tube 112 may be discharged to the gas discharge pipe 140 through the exterior 114 through the opening 116 formed at the upper portion of the inner tube 112. have. The boat 150 is also made of quartz.

In particular, the inner tube 112 according to the embodiment of the present invention has an opening 116 formed smaller than the diameter of the boat 150, a plurality of gas outlets 118 through the inner wall of the inner tube 112 is predetermined It has a structure formed vertically at intervals.

The reason why the inner tube 112 is formed as described above is to uniformly flow the reaction gas inside the inner tube 112 so as to deposit a thin film having a predetermined thickness on the wafer 160 loaded on the boat 150. That is, by forming the opening 116 formed on the upper portion of the inner tube 112 smaller than the diameter of the boat 150, the reaction gas supplied to the inner tube 112 is discharged to the outer appearance 114 through the opening 116. You can reduce the amount. In addition, the reduced reaction gas is discharged through the plurality of gas outlets 118 formed on the inner wall of the inner tube 112. Since the gas outlets 118 are formed in the direction in which the wafer 160 is loaded, the wafer 160 The reaction gas flows between the wafer 160 loaded on the boat 150 and the wafer 160 by inducing the flow of the reaction gas in a horizontal direction on both sides of the bottom surface). Can be deposited.

In addition, the gas outlet 118 formed in the inner tube 112 has a gas supply pipe 130 such that the reaction gas supplied through the gas supply pipe 130 may be uniformly supplied between the wafers 160 loaded on the boat 150. It is preferable to form on the opposite side of the installation, and at the same time it is more preferable to form toward the place where the gas discharge pipe 140 is installed so that the gas remaining reacted through the gas discharge pipe 140 can be stably discharged.

The gas supply pipe 130 into which the reaction gas is injected is connected to the inside of the inner tube 112, and is installed in parallel with the side surface of the inner tube 112. The gas supply pipe 130 has a short length and is provided near the bottom of the boat 150. The reaction gas is supplied upward from the top of the gas supply pipe 130 to deposit a thin film on the wafer 160, and the exhaust gas passing through the wafer is the opening 116 and the gas outlet at the top of the inner pipe 112. It is discharged to 118, and is discharged out of the double reaction tube 110 through the gas discharge pipe 140 connected between the inner tube 112 and the exterior 114.

In the CVD process using the CVD apparatus 200 according to an embodiment of the present invention, when the reaction shaft is supplied through the gas supply pipe 130 in a state in which the rotating shaft 170 on which the boat 150 is stored is rotated at a predetermined speed, In addition, the reaction gas moves to the plurality of gas outlets 118 in the inner tube 112 and deposits a thin film on the wafer 160 loaded on the boat 150 to a predetermined thickness, and the opening 116 of the inner tube. And the discharge gas including the reaction gas remaining after the reaction passed through the gas outlet 118 proceeds to the step of discharging out of the double reaction tube 110 through the gas discharge pipe 140.

Therefore, according to the structure of the present invention, since the amount of the reaction gas supplied from the gas supply pipe to the inner pipe is discharged to the outside through the opening of the inner pipe is reduced, and the amount discharged through the gas outlet formed on the inner wall of the inner pipe is increased, The horizontal flow of the reactant gas in the process increases, and the flow of the reactant gas in the inner tube becomes uniform, so that a thin film of uniform thickness can be deposited on the wafer loaded in the boat.

Claims (3)

A boat having a plurality of wafers loaded therein; A double reaction tube comprising an inner tube surrounding the boat and an outer appearance disposed outside the inner tube; A heating source disposed outside the exterior to heat the double reaction tube; A gas supply pipe for supplying a reaction gas to the inner pipe; And A gas discharge pipe installed between the inner pipe and the outer pipe and discharging the reaction gas out of the double reaction pipe; In order to uniformize the flow of the reaction gas in the inner tube, an opening smaller than the diameter of the boat is formed in the upper portion of the inner tube, and the inner wall of the inner tube is disposed at a predetermined interval in the direction in which the wafer is loaded. Chemical vapor deposition apparatus characterized in that a plurality of gas outlet is formed. The chemical vapor deposition apparatus according to claim 1, wherein the gas discharge port is formed on the opposite side of the gas supply pipe. 3. The chemical vapor deposition apparatus as claimed in claim 2, wherein the gas discharge port is formed toward a place where the gas discharge pipe is installed.