KR20050050788A - Deposition apparatus and deposition method - Google Patents

Abstract

The present invention relates to a low pressure chemical vapor deposition apparatus, the apparatus having a reaction chamber, a load lock chamber, a boat on which wafers are mounted, and a pressure regulator. When the boat between the reaction chamber and the load lock chamber is moved, the pressure controller adjusts the pressure of the load lock chamber so that the pressure difference between them is maintained within the set range. Pressure adjustment is performed by measuring the pressure difference between the reaction chamber and the load lock chamber by the differential pressure sensor, and controlling the flow rate of the purge gas supplied to the load lock chamber in consideration of the measured value.

Description

DEPOSITION APPARATUS AND DEPOSITION METHOD

The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly, to a deposition apparatus having a reaction chamber and a load lock chamber, and depositing a predetermined material on a wafer.

Low pressure chemical vapor deposition, which is used in a semiconductor manufacturing process, is a process of depositing a predetermined thin film on a semiconductor substrate by chemical reaction after decomposing a gaseous compound. In recent years, low pressure chemical vapor deposition apparatuses that have good uniformity of a deposited film, which can process a large amount of wafers at the same time, as well as low production cost due to low gas consumption, are mainly used.

The low pressure chemical vapor deposition apparatus generally used has a reaction chamber and a load lock chamber, and an opening and closing valve is installed between the reaction chamber and the load lock chamber to open and close a moving path of a boat loaded with wafers. When wafers are loaded into a boat located in the load lock chamber, an on-off valve is opened and the boat is moved to the reaction chamber. The on-off valve is closed and the process is performed, after which the boat is moved from the reaction chamber to the load lock chamber. The reaction chamber and the loadlock chamber must be maintained at the same pressure when the shutoff valve is opened and the boat is moved. If a large pressure difference occurs between them, the gas flow changes irregularly and particles are generated on the inner wall or boat of the reaction chamber, which contaminates the wafer.

It is an object of the present invention to provide a deposition apparatus that can prevent particles from being generated due to a pressure difference in the reaction chamber and the load lock chamber when the on-off valve is opened and the boat is moved between the reaction chamber and the load lock chamber.

In order to achieve the above object, the present invention deposition apparatus has a load lock chamber, a reaction chamber, a blocking portion, and a pressure adjusting portion. The load lock chamber is connected to an exhaust line provided with a pump to maintain the inside at a predetermined pressure, and a gas inflow line for introducing a predetermined gas into the load lock chamber, and a boat for mounting semiconductor substrates is located therein. The reaction chamber has a gas inlet line for introducing a predetermined gas therein and an exhaust line provided with a pump for maintaining the inside at a process pressure. The blocking unit opens and closes the movement path of the boat between the reaction chamber and the load lock chamber. The pressure control unit measures the pressure of the reaction chamber and the load lock chamber before the boat passage is opened, and adjusts the pressure difference between the reaction chamber and the load lock chamber according to the measured value, the reaction Pressure control of the chamber and the load lock chamber is performed by adjusting the amount of gas supplied to the reaction chamber or the amount of gas supplied to the load lock chamber.

In one embodiment, the pressure control unit is a gas inlet of the load lock chamber in accordance with the differential pressure sensor for measuring the pressure difference in the exhaust line of the load lock chamber and the pressure difference in the exhaust line of the reaction chamber and the differential pressure sensor It has a control unit for controlling the mass flow meter for adjusting the amount of gas supplied to the line.

Preferably the load lock chamber is adjusted to have a pressure of at least 0.5 KPa higher than the reaction chamber.

In addition, in the deposition method of the present invention, the pressure difference between the load lock chamber and the reaction chamber is measured, the purge gas is supplied to the load lock chamber or the reaction chamber, and the pressure difference between the load lock chamber and the reaction chamber is set within a range. Adjusting a gas flow rate supplied to the load lock chamber or the reaction chamber in consideration of the measured value, opening a moving path of a boat on which semiconductor substrates are mounted in the load lock chamber and the reaction chamber, And moving the boat between the load lock chamber and the reaction chamber.

In addition, the deposition method of the present invention comprises the steps of mounting the semiconductor substrates in the boat located in the load lock chamber, purge gas supplied to purge the interior of the load lock chamber, exhaust of the fluid in the load lock chamber, Measuring a pressure difference between the reaction chamber positioned above the load lock chamber and the load lock chamber, and purge gas is supplied into the load lock chamber, and a gas flow rate supplied to the load lock chamber is determined by the load lock chamber and the reaction chamber. Adjusting the pressure value within the set range in consideration of the measured value, opening a moving path of a boat having semiconductor substrates mounted in the load lock chamber and the reaction chamber, and moving the boat to the reaction chamber Blocking the movement path of the boat by a blocking plate installed in the boat, wherein the semiconductor substrate is in the reaction chamber. Depositing a predetermined material on the substrate, measuring a pressure difference between the reaction chamber and the load lock chamber, and purge gas is supplied into the load lock chamber, and a gas flow rate supplied to the load lock chamber is reacted with the load lock chamber. Adjusting the pressure value within the chamber in consideration of the measured value, lowering the boat into the load lock chamber, and blocking the movement path of the boat between the load lock chamber and the reaction chamber. It includes.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIGS. 1 to 2. The embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shape of the elements in the drawings are exaggerated to emphasize a clearer description.

1 schematically shows a low pressure chemical vapor deposition apparatus 1 according to a preferred embodiment of the present invention. Referring to FIG. 1, the apparatus 1 has a reaction chamber 100, a load lock chamber 200, a boat 300, and a pressure regulator 400. The reaction chamber 100 provides a space in which the deposition process is performed, and the load lock chamber 200 is provided below the reaction chamber 100 and selectively provides a space in communication with the reaction chamber 100. The load lock chamber 200 blocks contact with external air when loading semiconductor substrates such as the wafer W into the reaction chamber 100, thereby preventing the native oxide film from growing on the wafer W. FIG.

The load lock chamber 200 has a cylindrical shape having a hole formed in the center of the upper surface thereof, and an opening / closing valve 220 for opening and closing a passage through which the wafers W are received between the outside and the load lock chamber 200 at one side central portion thereof. Is installed. An inlet port 262 through which purge gas is introduced to purge the inside of the load lock chamber 200 is formed at a lower end of one side of the load lock chamber 200, and a purge gas inlet 280 is formed at the inlet port 262. Connected. The purge gas inlet 280 is provided with an inlet line 282 connected to the inlet port 262 and a mass flow controller (MFC) 284 for controlling the flow rate of the gas flowing in the inlet line 282. do. Nitrogen gas may be used as the purge gas. An exhaust port 264 is formed at the other lower end of the load lock chamber 200, and the exhaust port 264 forces fluid in the load lock chamber 200 to maintain a predetermined vacuum in the load lock chamber 200. An exhaust line 292 to which the suction pump 294 is connected is connected. Each of the inflow line 282 and the exhaust line 292 is provided with a valve for opening and closing the inner passage.

The reaction chamber 100 is placed perpendicular to the top surface of the load lock chamber 200. The reaction chamber 100 has an outer tube 110 and an inner tube 120 made of quartz as part of a deposition process. The inner tube 120 has a cylindrical shape with both the upper and lower portions open, and the outer tube 110 is installed to surround the inner tube 120 and has a cylindrical shape with the lower portion open. Outside the outer tube 110, a heater 160 for pyrolyzing the reaction gases introduced into the reaction chamber 100 and heating the reaction chamber 100 to a temperature at which a chemical reaction may occur is disposed. Heater 160 may be adjusted to approximately 450 to 840 ℃.

The inner tube 120 and the outer tube 110 are disposed below the flange 130 is formed with a hole in the center. A support 132 on which the outer tube 110 is placed is formed at an upper end of the flange 130, and a support 134 on which the inner tube 120 is placed protrudes from an inner wall of the flange 130. An O-ring (not shown) may be installed between the outer tube 110 and the flange 130 to seal the inside of the reaction chamber 100 from the outside. One side of the flange 130 is a reaction gas inlet lines (not shown) to which reaction gases are supplied, and a purge gas inlet line to which purge gas such as nitrogen is supplied to prevent a natural oxide film from being formed on the wafer W. A plurality of ports 136 to which 182 is connected are formed. The purge gas inlet line 182 is provided with a mass flow meter (MFC) 184 for controlling the amount of nitrogen gas supplied into the reaction chamber 100. An exhaust port 138 is formed at the other side of the flange 130, and an exhaust line 192 having a pump 194 is connected to the exhaust port 138. During the process, the reaction chamber 100 is maintained at a predetermined vacuum by the pump 194 and the reaction by-products in the reaction chamber 100 are exhausted through the exhaust line 192. Reaction gas inlet lines, purge gas inlet line 182, and exhaust line 192 are each provided with a valve for opening and closing their internal passage.

The boat 300 is a portion in which the wafers W on which the process is performed are mounted. The boat 300 mounts about 50 to 100 wafers W at a time. The boat 300 has an upper pedestal 320 positioned to be spaced apart from the lower pedestal 340 horizontally and facing the lower pedestal 340. A plurality of vertical supports 360 are installed between the lower support 340 and the upper support 320, and slots into which the edges of the wafer W are inserted are formed in each vertical support 360. Under the boat 300, a driving unit (not shown) for moving the boat 300 up and down and rotating it is coupled. As the driving unit, various driving apparatuses such as a stepping motor or a hydraulic cylinder may be used. The boat 300 moves through the load lock chamber 200 and the space in the reaction chamber 100 by the driving unit. The blocking unit 240 has an opening / closing valve 242 and a blocking plate 244 as a part for opening and closing the moving path 270 of the boat 300 between the load lock chamber 200 and the reaction chamber 100. The on-off valve 242 is located between the load lock chamber 200 and the reaction chamber 100, the blocking plate 244 is coupled to the lower end of the boat 300 is raised and lowered with the boat 300. While the boat 300 is located in the load lock chamber 200, the moving path 270 of the boat 300 is blocked by the opening / closing valve 242, and when the boat 300 is moved to the reaction chamber 100, the boat The movement path 270 of the 300 is blocked by the blocking plate 244.

If the pressure difference between the load lock chamber 200 and the reaction chamber 100 is large while the boat 300 is moved between the load lock chamber 200 and the reaction chamber 100, the flow of air flow becomes turbulent. As a result, the reaction by-products scatter from the inner wall of the inner tube 120 to act as particles. The pressure control unit 400 is to prevent this, and controls the pressure difference between the load lock chamber 200 and the reaction chamber 100 to be within a predetermined value before the on-off valve 242 is opened. The pressure regulator 400 has a differential pressure sensor 420 and a controller 440. The differential pressure sensor 420 is connected to the branch pipe 452 branched from the exhaust line 192 connected to the reaction chamber 100 and the branch pipe 462 branched from the exhaust line 292 connected to the load lock chamber 200. To calculate the pressure difference between them. Each branch line 452, 462 is provided with an on-off valve (454, 464). The controller 440 automatically adjusts the amount of gas supplied to the load lock chamber 200 to maintain the pressure difference between the reaction chamber 100 and the load lock chamber 200 in consideration of the pressure difference transmitted from the differential pressure sensor 420. To control the mass flow meter 284. According to an example, the pressure of the load lock chamber 200 may be adjusted to be maintained at 0.5 KPa or more than the pressure of the reaction chamber 100, and then the moving path 270 of the boat 300 may be opened.

A flow meter (not shown) may be installed in the exhaust line 292 of the load lock chamber, and the flow meter may be adjusted for pressure control in the load lock chamber 200. However, in this case, it is difficult to precisely control the exhaust flow rate, so that the pressure in the load lock chamber 200 is not precisely adjusted, and it is very cumbersome because the worker has to do it manually. On the contrary, when the flow rate of the nitrogen gas supplied to the load lock chamber 200 is adjusted, not only the pressure in the load lock chamber 200 can be precisely adjusted, but also the mass flow meter 284 can be easily controlled automatically. Therefore, as described in this embodiment, the pressure control in the load lock chamber 200 is achieved by controlling the flow rate supplied into the load lock chamber 200 by controlling the mass flow meter 284 installed in the purge gas inlet line 282. desirable.

In the present embodiment, the pressure difference between the load lock chamber 200 and the reaction chamber 100 measures the pressure in the exhaust line 292 connected to the load lock chamber 200 and the exhaust line 192 connected to the reaction chamber 100. It has been described as being made by the differential pressure sensor 420. However, unlike this, a sensor for measuring the pressure in the load lock chamber 200 and a sensor for measuring the pressure in the reaction chamber 100 are respectively installed, and the measured values are transmitted to the control unit 440 in the control unit 440. The pressure difference can be calculated.

In addition, in the present embodiment, the adjustment of the pressure difference between the load lock chamber 200 and the reaction chamber 100 has been described as being made by controlling the amount of nitrogen gas supplied to the load lock chamber 200. Alternatively, however, adjustment of the pressure difference may be achieved by controlling the amount of nitrogen gas supplied to the reaction chamber.

2 is a flowchart sequentially showing how a deposition process is performed using the apparatus 1 described above. Referring to FIG. 2, an opening / closing valve 220 installed on a sidewall of the load lock chamber 200 is opened, and wafers W loaded on a cassette (not shown) are moved by a transfer robot (not shown). 300) (step S11). When all of the wafers W are mounted, the opening / closing valve 220 is closed, and nitrogen gas is supplied into the load lock chamber 200 to purge the inside of the load lock chamber 200 (step S12). When the nitrogen gas approaches the normal pressure, the on / off valve provided in the exhaust line 292 is opened and the nitrogen gas in the load lock chamber 200 is exhausted by the operation of the pump 294 (step S13). Thereafter, the pressure difference between the load lock chamber 200 and the reaction chamber 100 is measured by the differential pressure sensor 420 (step S14), and nitrogen gas is introduced into the load lock chamber 200 from the purge gas inlet line 262. . At this time, the control unit 440 controls the mass flow meter 284 to adjust the amount of nitrogen gas so that the pressure difference between the load lock chamber 200 and the reaction chamber 100 is maintained within the set range (step S15). Thereafter, the on-off valve 242 which opens the moving path 270 of the boat 300 is opened (step S16). The boat 300 is elevated into the reaction chamber 100, and the moving path 270 of the boat 300 is closed by the blocking plate 244 (step S17). Thereafter, a deposition process is performed in the reaction chamber 100 (step S18). When the deposition process is completed in the reaction chamber 100, the pressure difference between the reaction chamber 100 and the load lock chamber is again measured (step S19), and the pressure difference between the reaction chamber 100 and the load lock chamber 200 is set within the set range. The nitrogen gas of the amount adjusted so that it may become inside is supplied to the load lock chamber (step S20). The boat 300 descends to the load lock chamber 200 (step S21), and the opening / closing valve 242 is closed to block the moving path 270 of the boat 300 (step S22).

According to the present invention, since the pressure difference between the reaction chamber and the load lock chamber is maintained to be in a predetermined range before the boat movement path between the reaction chamber and the load lock chamber is opened, the flow of air can be kept constant when the boat is raised and lowered. Therefore, there is an effect that can prevent the generation of particles.

In addition, according to the present invention, since the pressure in the load lock chamber is adjusted by adjusting the amount of nitrogen gas supplied to the load lock chamber, pressure control can be accurately performed.

In addition, according to the present invention there is an effect that the pressure adjustment can be made automatically because the mass flow meter is adjusted in the control unit in consideration of the pressure difference measured by the differential pressure sensor.

1 is a view schematically showing a low pressure chemical vapor deposition apparatus according to an embodiment of the present invention;

FIG. 2 is a flowchart sequentially illustrating a deposition method using the apparatus of FIG. 1.

Explanation of symbols on the main parts of the drawings

100: reaction chamber 110: outer tube

120: inner tube 130: flange

184: mass flow meter 194: pump

200: load lock chamber 242: on-off valve

244: blocking plate 284: mass flow meter

294: pump 300: boat

400: pressure regulator 420: differential pressure sensor

440: control unit

Claims (6)

A deposition apparatus for depositing a predetermined material on semiconductor substrates, A load lock chamber having a boat on which semiconductor substrates are mounted, and an exhaust line to which a pump for maintaining the interior at a predetermined pressure is connected, and a gas inflow line for introducing a predetermined gas therein; A reaction chamber connected to the load lock chamber and providing a space in which a deposition process is performed on a semiconductor substrate, and having a gas inlet line for introducing a predetermined gas therein and an exhaust line connected with a pump for maintaining the inside at a process pressure Wow; A blocking unit for opening and closing the boat movement path between the reaction chamber and the load lock chamber; The pressure control unit for measuring the pressure of the reaction chamber and the load lock chamber before the moving path of the boat is opened, and adjusts the pressure difference between the reaction chamber and the load lock chamber according to the measured value, Pressure control of the reaction chamber and the load lock chamber is made by adjusting the amount of gas supplied to the reaction chamber or the amount of gas supplied to the load lock chamber. The method of claim 1, The pressure control unit, A differential pressure sensor for measuring a pressure in an exhaust line of the load lock chamber and a pressure difference in an exhaust line of the reaction chamber; And a controller for controlling a mass flow meter for adjusting the amount of gas supplied to the gas inflow line of the load lock chamber according to the value measured by the differential pressure sensor. The method according to claim 1 or 2, And the load lock chamber is adjusted to have a pressure of 0.5 KPa or higher than the reaction chamber. Measuring the pressure difference between the load lock chamber and the reaction chamber; Supplying purge gas to the load lock chamber or the reaction chamber; Adjusting a gas flow rate supplied to the load lock chamber or the reaction chamber in consideration of the measured value such that the pressure difference between the load lock chamber and the reaction chamber is within a set range; Opening a moving path of a boat on which semiconductor substrates are mounted in the load lock chamber and the reaction chamber; And And the boat is moved between the loadlock chamber and the reaction chamber. The semiconductor substrates are mounted in a boat located in the loadlock chamber; Purge gas is supplied to purge the inside of the load lock chamber; Evacuating fluid in the loadlock chamber; Measuring a pressure difference between the reaction chamber located above the load lock chamber and the load lock chamber; Purge gas is supplied into the load lock chamber, and the gas flow rate supplied to the load lock chamber is adjusted in consideration of the measured value such that a pressure difference between the load lock chamber and the reaction chamber is within a set range; Opening a moving path of the boat on which the semiconductor substrates are mounted in the load lock chamber and the reaction chamber; Moving the boat to the reaction chamber and blocking the moving path of the boat by a blocking plate installed in the boat; And And depositing a predetermined material on the semiconductor substrate in the reaction chamber. The method of claim 5, The method, Measuring a pressure difference in the reaction chamber and the load lock chamber; Purge gas is supplied into the load lock chamber, and the gas flow rate supplied to the load lock chamber is adjusted in consideration of the measured value such that a pressure difference between the load lock chamber and the reaction chamber is within a set range; The boat is lowered into the loadlock chamber; And And the movement path of the boat is blocked between the load lock chamber and the reaction chamber.