KR20070066712A - Loadlock chamber of low pressure chemical vapor deposition apparatus - Google Patents

Abstract

A loadlock chamber of an LPCVD apparatus is provided to prevent external air from being introduced into a chamber by making the inner pressure of the chamber having a pressure higher than the atmospheric pressure and maintaining the pressure before a door of the chamber opens to transport a wafer. A shutter(114) for opening/shutting a connection path to a vertical furnace(10) and a door(112) for transporting a wafer are installed in a chamber(110). A pressure gauge(118) measures the inner pressure of the chamber. A nitrogen gas supply source supplies nitrogen gas to the inside of the chamber. A vacuum pump(134) is connected to the chamber by a pumping line(130) in which a main valve(132) is installed. The nitrogen gas is exhausted by an exhaust line(140). The flowrate of the exhaust line is adjusted by a throttle valve(142). Based upon the pressure data measured by the pressure gauge, the main valve and the throttle valve are controlled by a controller(150). The exhaust gas can be purified by a scrubber(138) connected to the vacuum pump and the exhaust line.

Description

LOADLOCK CHAMBER OF LOW PRESSURE CHEMICAL VAPOR DEPOSITION APPARATUS}

1 is a schematic configuration diagram of a load lock chamber provided in the LP CVD apparatus according to the present invention.

** Description of the symbols for the main parts of the drawings **

10: vertical furnace 12: process gas supply line

110: chamber 112: door

114: shutter 116: elevator

118: pressure gauge 120: nitrogen gas source

122: nitrogen gas supply line 124: flow regulator

130: pumping line 132: main valve

134: vacuum pump 138: scrubber

140: exhaust line 142: throttle valve

150: controller

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to manufacturing equipment for semiconductor devices, and more particularly, to a load lock chamber of a low pressure chemical vapor deposition (LP CVD) apparatus.

Generally, a semiconductor device is manufactured by selectively and repeatedly performing a process such as photographing, etching, diffusion, ion implantation, metal deposition, and chemical vapor deposition on a wafer, which is a semiconductor substrate.

Among them, the LP CVD process, which is one of chemical vapor deposition processes, is a process for depositing a predetermined film, for example, a polysilicon film, a silicon nitride film, or a silicon oxide film, on the wafer, and has excellent uniformity of the deposited film at once. It is preferred to reduce the production cost because it is possible to form a high quality deposited film on a large number of wafers.

The LP CVD process is characterized in that the internal pressure of the vertical furnace in which a predetermined film is deposited is maintained at a low pressure, that is, a high vacuum atmosphere, thereby excluding process influences by particles.

However, when the wafer is directly supplied into the vertical furnace, the process conditions inside the vertical furnace to be precisely maintained, that is, the high vacuum atmosphere may be unstable, and the high vacuum atmosphere acts as a stress on the wafer. This can act as a cause of process defects.

Therefore, in general, the LP CVD apparatus, which is an apparatus for performing the LP CVD process, is provided with a load lock chamber connected to the vertical furnace. The load lock chamber is a buffer chamber, which allows the wafer to be exposed to environmental conditions close to the process conditions inside the vertical furnace before the wafer is immediately supplied into the vertical furnace, and the process conditions inside the vertical furnace are influenced from the outside. It acts as a blocking space to block receiving.

The load lock chamber is adjusted to maintain the atmospheric pressure when the wafer is brought in from the outside and the wafer which has been processed is taken out. The load lock chamber is regulated to an atmospheric pressure state by supplying nitrogen gas, which is a purge gas.

In more detail, while supplying nitrogen gas into the load lock chamber through a purge line, the internal gas of the load lock chamber is discharged through an exhaust line, which is a kind of vacuum line. At this time, the valve for opening and closing the exhaust line is maintained in the open state, the nitrogen gas into the load lock chamber while adjusting the amount of nitrogen gas so that the internal pressure of the load lock chamber measured by the pressure gauge is formed at atmospheric pressure state To supply. When the inside of the load lock chamber is formed under the atmospheric pressure through the above process, a door provided at one side of the load lock chamber is opened to carry in or take out the wafer.

By the way, the internal pressure of the load lock chamber formed through the above-described process is expected to be maintained at atmospheric pressure by design, but the pressure is relatively increased by the pressure difference between the internal and external pressure of the load lock chamber when the door is opened due to various factors. From this high outside, a phenomenon in which external air rapidly enters into the load lock chamber may occur. This inflow of external air may contaminate the wafer with the inflow of particles contained therein. In addition, process defects may be caused by forming an unwanted natural oxide film on the wafer surface by oxygen contained in the outside air.

The present invention has been made to overcome the disadvantages of the prior art as described above, to provide a load lock chamber of the LPCVD apparatus to prevent the outside air flow into the load lock chamber when opening the door for loading and unloading the wafer Is a technical task.

The load lock chamber of the LP CVD apparatus according to the present invention for achieving the above technical problem is a chamber provided with a shutter for opening and closing the connection passage to the vertical furnace and the door for loading and unloading the wafer, the internal pressure of the chamber A pressure gauge for measuring a pressure, a nitrogen gas supply source for supplying nitrogen gas into the chamber, a vacuum pump connected to the chamber through a pumping line provided with a main valve, and an exhaust line for exhausting the nitrogen gas from the chamber; And a throttle valve for adjusting the flow rate of the exhaust line, and a controller for controlling the main valve and the throttle valve based on the pressure data measured through the pressure gauge.

In one embodiment, upon opening of the door for loading and unloading the wafer, the internal pressure of the chamber is maintained above atmospheric pressure by adjusting the flow rate of the exhausted nitrogen gas through the control of the throttle valve by the controller. .

In another embodiment, when opening the door for loading and unloading the wafer, the nitrogen gas is blocked by controlling the throttle valve by the controller, and the supply amount of the nitrogen gas supplied into the chamber is controlled. This allows the internal pressure of the chamber to be maintained above atmospheric pressure.

In another embodiment, a scrubber may be further provided to purify the exhaust gas connected to the vacuum pump and the exhaust line.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided to ensure that the disclosed subject matter is thorough and complete, and that the scope of the invention to those skilled in the art will fully convey. On the other hand, the shape and the like of the elements in the accompanying drawings is preferably understood to be somewhat exaggerated for clearer description, the same reference numerals throughout the specification represent the same components.

1 is a schematic configuration diagram of a load lock chamber provided in the LP CVD apparatus according to the present invention.

As shown in FIG. 1, the load lock chamber 100 of the LP CVD apparatus according to the present invention is disposed below the vertical furnace 10 in which the actual LP CVD process is performed. Prior to the description of the load lock chamber 100 according to the present invention briefly described with respect to the longitudinal furnace 10, the longitudinal furnace 10 is composed of a double tube consisting of an inner tube and an outer tube not shown The heater is provided on the outside of the double tube. One side of the vertical furnace 10 is connected to the process gas supply line 12 for supplying the process gas into the inner tube, the other side of the vertical furnace 10 is a low pressure, that is, predetermined A vacuum pump (not shown) for forming in a vacuum state is connected by the pumping line 14.

On the other hand, the load lock chamber 100 is a kind of buffer chamber, before the wafer (W) is immediately supplied into the vertical furnace 10, the environmental conditions close to the process conditions inside the vertical furnace 10 And it also serves as a blocking space to block the process conditions inside the vertical furnace 10 from being influenced from the outside.

The load lock chamber 100 includes a chamber 110 in which a shutter 114 for opening and closing a connection passage with the vertical passage 10 and a door 112 for loading and unloading the wafer W are provided. An elevator for loading and unloading the boat 20 into the vertical furnace 10 by raising and lowering the boat 20 loaded with a plurality of wafers W inside the chamber 110 ( 116 is disposed.

The chamber 110 is connected to a nitrogen gas supply source 120 for supplying nitrogen gas into the chamber 110 through a nitrogen gas supply line 122. The nitrogen gas is supplied when the inside of the chamber 110 is formed at atmospheric pressure, and the purge operation is performed to purge the inside of the chamber 110. The nitrogen gas supply line 122 is provided with a flow regulator 124 for adjusting the supply amount of the nitrogen gas, the flow regulator 124 and the pressure gauge 118 for measuring the internal pressure of the chamber 110 and It is controlled by the connected controller 150.

The chamber 110 is also connected with a vacuum pump 134 through the pumping line 130 to form the inside of the chamber 110 at a low pressure, that is, a predetermined vacuum state. The main valve 132 for adjusting the vacuum degree is installed on the pumping line 130, and the main valve 132 is controlled by the controller 150 described above. The scrubber 138 is connected to the rear end of the vacuum pump 134 through the pumping line 130. The scrubber 138 is for purifying harmful exhaust gas and discharging it into the atmosphere. Mainly used.

The chamber 110 is also connected to an exhaust line 140 for exhausting nitrogen gas supplied into the chamber 110. The exhaust line 140 is connected to the scrubber 138 through the pumping line 130 so that nitrogen gas and other residual gas exhausted through the exhaust line 140 are purged through the scrubber 138 and then atmosphere. To be released. Here, the exhaust line 140 may be directly connected to the scrubber 138. The throttle valve 142 controlled by the controller 150 is installed on the exhaust line 140 to adjust the flow rate of nitrogen gas and the like exhausted through the exhaust line 140.

Hereinafter, the operation of the load lock chamber 100 according to the present invention having the above configuration will be described.

First, prior to opening the door 112 provided on one side of the chamber 110 in order to load the wafer (W), which is a process object, in the boat 20 disposed inside the chamber 110, the chamber 110 The interior is formed at atmospheric pressure.

Looking at the process for forming the inside of the chamber 110 to the atmospheric pressure, while supplying nitrogen gas from the nitrogen gas source 120 into the chamber 110, while exhausting the nitrogen gas through the exhaust line 140 do. In this case, the amount of nitrogen gas supplied into the chamber 110 and the amount of nitrogen gas exhausted through the exhaust line 140 are data on the internal pressure of the chamber 110 measured through the pressure gauge 118. It is controlled through the control of the controller 150 based on this, thereby forming the inside of the chamber 110 to atmospheric pressure.

On the other hand, even though it is confirmed through the pressure gauge 118 that the inside of the chamber 110 is formed at atmospheric pressure, there may be a pressure difference with the outside of the chamber 110, and thus, when the door 112 is opened, From the outside air may be introduced into the chamber 110. In order to prevent this, in the present invention, the internal pressure of the chamber 110 is formed higher than atmospheric pressure before the door 112 is opened to maintain it.

One embodiment for this purpose is to maintain the amount of nitrogen gas supplied through control of the flow regulator 124, the chamber by reducing the amount of nitrogen gas exhausted through the control of the throttle valve 142 The internal pressure of 110 is formed higher than atmospheric pressure to maintain it. In another embodiment, the chamber 110 is controlled by blocking the exhaust of nitrogen gas through the control of the throttle valve 142, and controlling the amount of nitrogen gas supplied through the control of the flow regulator 124. The internal pressure of the is formed higher than atmospheric pressure to maintain it.

Under such a state, even when the door 112 is opened, the internal pressure of the chamber 110 is higher than atmospheric pressure, so that the outside air can be prevented from entering the inside of the chamber 110, thereby preventing the inflow of the outside air. According to the related art, it is possible to prevent a process defect caused by contamination of the wafer W due to particles or the formation of an unwanted natural oxide film on the surface of the wafer.

After the loading of the wafer W into the boat 20 is completed, the door 112 is closed, and the chamber 110 is operated through the operation of the vacuum pump 134 and the control of the main valve 132 by the controller 150. ) Is formed at low pressure, that is, under vacuum. At the same time, the inside of the vertical furnace 10 also forms a vacuum state corresponding to the process conditions by the operation of a vacuum pump (not shown).

When the inside of the vertical furnace 10 and the pressure in the chamber 110 are equal, the shutter 114 is opened and the elevator 116 is operated so that the boat 20 loaded with a plurality of wafers W is loaded. The inside of the vertical furnace 10 is sealed while being loaded into the vertical furnace 10, the vacuum pump 134 stops the pumping operation, and the main valve 132 is closed.

Thereafter, the process gas is introduced into the vertical furnace 10 through the process gas supply line 12, and a predetermined film is deposited on the wafer W. When the deposition is completed, the supply of the process gas into the vertical furnace 10 is stopped and the purge gas is supplied instead, while the pumping action is performed by the vacuum pump to perform the exhaust and purge of unreacted residual gas. When the exhaust and purge action is completed, the boat 20 is unloaded to the outside of the vertical path 10 through the operation of the elevator 116, the shutter 114 is closed.

Subsequently, as described above, the inside of the chamber 110 is formed at atmospheric pressure, and the chamber before the door 112 is opened, as described above, in order to transport the wafer W having the deposition process completed to the outside of the chamber 110. The internal pressure of 110 is formed higher than atmospheric pressure to maintain it. Under such a state, the door 112 is opened to allow the wafer W having the deposition process completed to be carried out of the chamber 110.

As described above, in the detailed description of the present invention has been described with respect to preferred embodiments of the present invention, those skilled in the art to which the present invention pertains various modifications without departing from the scope of the present invention Of course it is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the claims below, but also by the equivalents of the claims.

According to the present invention having the configuration as described above, by maintaining the internal pressure of the chamber higher than the atmospheric pressure prior to opening the door for loading and unloading the wafer so that the outside air does not flow into the chamber when opening the door. do. Therefore, there is an advantage of preventing process defects caused by wafer contamination due to particles caused by inflow of external air or by forming an unwanted natural oxide film on the surface of the wafer.

Claims (4)

A chamber provided with a shutter for opening and closing a connection passage with a vertical passage and a door for carrying in and out of a wafer; A pressure gauge for measuring the internal pressure of the chamber; A nitrogen gas supply source for supplying nitrogen gas into the chamber; A vacuum pump connected to the chamber through a pumping line provided with a main valve; An exhaust line for exhausting the nitrogen gas from the chamber; A throttle valve for adjusting a flow rate of the exhaust line; And a controller for controlling the main valve and the throttle valve based on the pressure data measured by the pressure gauge. The method of claim 1, When opening the door for loading and unloading the wafer, the internal pressure of the chamber is maintained higher than atmospheric pressure by adjusting the flow rate of nitrogen gas exhausted through the control of the throttle valve by the controller. Load lock chamber of LP CVD apparatus. The method of claim 1, When opening the door for loading and unloading the wafer, the exhaust of the nitrogen gas is blocked by controlling the throttle valve by the controller, and the supply amount of the nitrogen gas supplied into the chamber is controlled to control the throttle valve. The load lock chamber of an LP CVD apparatus, characterized in that the internal pressure is maintained above atmospheric pressure. The method of claim 1, And a scrubber connected to the vacuum pump and the exhaust line to purify the exhaust gas.

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