KR20040110820A - Low pressure chemical vapor deposition apparatus used in manufacturing semiconductor devices - Google Patents

Abstract

PURPOSE: A low pressure chemical vapor deposition apparatus for manufacturing a semiconductor device is provided to prevent a breakage of an outer tube by reducing an amount of gas vaporized on an upper surface of the outer tube. CONSTITUTION: A low pressure chemical vapor deposition apparatus includes a flange(200), an inner tube(120), an outer tube(140), a boat(300), and a shielder(500). The flange includes at least one gas inlet and a gas injecting hole. The inner tube is supported by the flange and has a cylindrical form with open upper and lower portions. The outer tube is supported by the flange and includes an open lower portion which encloses a perimeter of the inner tube with a spacing from the inner tube and a convex outer portion. The boat is moved to the inner tube and contains a plurality of semiconductor wafers. The shielder is positioned between the upper portion of the outer tube and an upper plate of the boat to minimize a region formed below an upper surface of the outer tube.

Description

LOW PRESSURE CHEMICAL VAPOR DEPOSITION APPARATUS USED IN MANUFACTURING SEMICONDUCTOR DEVICES

The present invention relates to an apparatus for manufacturing a semiconductor device, and more particularly to a low-pressure chemical vapor apparatus for performing a deposition process for a plurality of wafers.

The chemical vapor deposition process used in the semiconductor manufacturing process is a process of depositing a certain thin film on a semiconductor substrate by decomposing a gaseous compound and then chemically reacting. Recently, the uniformity of the deposited film is good and a large amount of wafers is used. The low pressure chemical vapor deposition apparatus which can not only simultaneously process but also have low production cost due to low gas consumption is mainly used.

FIG. 1 is a view illustrating a general low pressure chemical vapor apparatus, and the low pressure chemical vapor deposition apparatus includes an inner tube 640, an outer tube 660, and a boat 680 placed on a flange 620. The inner tube 640 has a cylindrical shape with the top and bottom open, the side of the outer tube 660 is formed in a cylindrical shape surrounding the inner tube 640, the upper surface 664 of the outer tube It has a rounded shape.

In general, the process gas supplied from the reaction gas supply pipe 622 inserted through the flange 620 is deposited in the wafers W mounted in the boat 680 while flowing into the inner tube 640 and flowing upward, and remaining. Gas flows down through the space between the inner tube 640 and the outer tube 660 and is exhausted through the exhaust pipe 624. The upper surface 664 of the outer tube generally has a convex rounded shape to the top to prevent breakage at low pressure.

Due to the above-described shape, the distance between the top plate 682 of the boat and the top surface 664 of the outer tube is the distance between the boat 680 and the inner tube 640 and the inner tube 640 and the outer tube sidewall 666. ) Wider than the gap between This causes the process gas to move relatively slowly in the space between the top plate 682 of the boat and the top surface 664 of the outer tube, and a relatively large amount of process gases are deposited on the upper surface 664 of the outer tube. Later, the film deposited on the upper surface 640 of the outer tube causes stress, which causes cracks in the surface of the upper surface 640 of the outer tube. This causes particles and breaks in the outer tube during the process.

An object of the present invention is to provide a low-pressure chemical vapor deposition apparatus that can prevent the deposition of a large amount of process gas on the upper plate of the outer tube due to the slow movement of the process gas under the upper plate of the outer tube.

1 is a cross-sectional view of a general low pressure chemical vapor deposition apparatus;

2 is a cross-sectional view of a low pressure chemical vapor deposition apparatus according to an embodiment of the present invention;

3A and 3B are a front view and a plan view, respectively, of the protection portion of FIG. 2;

4 is a cross-sectional view of a low pressure chemical vapor deposition apparatus according to another embodiment of the present invention; and

5A and 5B are front and plan views, respectively, of the protection part of FIG. 4.

Explanation of symbols on the main parts of the drawings

100: reaction chamber 120: outer tube

122: outer tube upper surface 140: inner tube

200: flange 300: boat

312 boat top plate 500 protector

520: upper body 540: lower body

In order to achieve the above object, the low pressure chemical vapor deposition apparatus of the present invention is supported by a flange having at least one gas inlet and a gas exhaust port, a cylindrical inner tube which is supported by the flange and whose upper and lower sides are opened, and is supported by the flange. An outer tube which surrounds the outer periphery of the inner tube at a distance from the inner tube and has an open lower portion and an upper portion of the upper convex shape, and a plurality of semiconductor substrates, and the inner tube of the inner tube during the process Have a boat moved to. In addition, the protective part is located between the upper surface of the outer tube and the upper surface of the boat to minimize the size of the space formed below the upper portion of the outer tube.

In one embodiment, the protective part has an upper body having a convex shape, a lower body coupled to a lower portion of the upper body and formed in a flat plate shape, protruding downward on the bottom of the upper body and placed on an upper sidewall of the inner tube. Protuberances are formed.

According to another example, the protective part has a lower body having a cylindrical shape of the same size as the upper plate of the boat and an upper body extending upward from the lower body and convexly rounded upwards, At the bottom of the body, projections are placed on the top plate of the boat.

Hereinafter, embodiments of the present invention will be described in more detail with reference to FIGS. 2 to 5. In the drawings, the same reference numerals are given to components that perform the same function.

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.

2 is a view showing a schematic configuration of a vertical furnace type low pressure chemical vapor deposition apparatus according to an embodiment of the present invention. Referring to FIG. 2, the low pressure chemical vapor deposition apparatus 10 has a reaction chamber 100, a boat 300, a flange, and a shield 500.

The reaction chamber 100 includes an inner tube 120, an outer tube 140, and a flange 200 as a deposition process. The inner tube 120 is made of quartz and has a hollow cylindrical shape with both top and bottom open. The outer tube 140 is made of quartz, and has an upper side and an open side surface 124 and an upper surface 122 sealing the open upper portion. The side surface 124 of the outer tube has a cylindrical shape to surround the inner tube 140, the upper surface 122 of the outer tube has a convex rounded shape toward the top to prevent breakage at low pressure. . A heater 600 may be installed outside the outer tube 120 to maintain the inside of the reaction chamber 100 at a high temperature during the process.

The flange 200 has a cylindrical shape, and a through hole 250 that is a moving passage of the boat is formed at the center thereof. A pedestal 220 protruding outward is formed at the outer upper end of the flange 200 to support the outer tube 120, and a disk-shaped pedestal 240 for supporting the inner tube 140 is protruded inward at the inner central portion. It is.

One side of the flange 200 is formed with an inlet 260 into which the process gas supply pipe 262 is inserted. Process gas is introduced into the inner tube 140 to form a deposition film on the wafers (W) mounted on the boat (300). Inlet 260 may be formed in a larger number depending on the type of process. A purge gas injection port (not shown) connected to the purge gas supply pipe may be formed below the inlet 260. The purge gas serves to remove air in the reaction chamber 100 to prevent a natural oxide film from being formed on the wafer W, and nitrogen gas may be used as the purge gas. On the side of the flange 200 facing the inlet 260, an exhaust port 280 is formed which is connected to the exhaust pipe 282 to form a low pressure atmosphere and discharge gas during the process.

The boat 300 is for mounting a plurality of wafers W, and has a top plate 312, a bottom plate 314, and connecting rods 320, and is made of quartz. The upper plate 312 and the lower plate 314 are formed in a circular flat plate, and approximately three to four connecting rods 320 having a long length are disposed between the upper plate 312 and the lower plate 314. One end of each of the connecting rods 320 may be coupled to the upper plate 312, and the other end may be coupled to the lower plate 314. Each connection rod 320 may be formed with protrusions 322 on which an edge of the wafer W is placed.

Below the lower plate 314 of the boat is disposed a moving device 400 for lifting the boat 300 up and down. The moving device 400 is coupled to the support rods 440 supporting the boat 300 and the support rods 440 and moved up and down by a driving unit (not shown), such as a cylinder, to a motor (not shown). It has a support plate 460 rotated by. The boat 300 is moved into the inner tube through a through hole 250 formed in the flange 200 from a load lock chamber (not shown) disposed below the reaction chamber 100.

A plurality of heat sinks 420 are coupled to the support rod 440 to maintain a constant temperature in the reaction chamber 100. In a general low pressure chemical vapor deposition apparatus, the heat sinks are densely arranged in a position from the center to the bottom of the support rod to form a large empty space under the bottom plate of the boat. This slows the movement of the process gas, which causes a large amount of process gas to deposit on the bottom plate of the boat. These are later acted as particles. In order to prevent this, in the present embodiment, the heat sinks 420 are uniformly disposed up and down from one end of the support rod 440 to the other end. As a result, process gases may flow at a uniform speed from the bottom to the top in the inner tube 140.

In addition, as described above, the upper surface 122 of the outer tube has a rounded shape to protrude upward, and the upper plate 312 of the boat has a flat shape. Therefore, a wide space is formed between the upper plate 312 of the boat and the upper surface 122 of the outer tube, the process gas flowing from the bottom in the inner tube flows at a slow speed in the space. As a result, a large amount of process gas is deposited on the upper surface 122 of the outer tube. The deposited film is then cracked, which causes the outer tube 120 to break.

In order to prevent this, in the present embodiment, a protective part 500 is disposed between the upper surface 122 of the outer tube and the upper plate 312 of the boat and has a predetermined volume. 3A and 3B are front and plan views, respectively, of the protection part 500 shown in FIG. 2. 3A and 3B, the protection part 500 is made of quartz and has an upper body 520 and a lower body 540. The upper body 520 has a convex upward shape like the upper surface 122 of the outer tube, a plurality of protrusions 522 placed on the upper end of the inner tube 140 on the lower edge of the upper body 520 Is formed. A cylindrical lower body 540 having a lower surface having the same size as the upper plate 312 of the boat is positioned below the upper body 520. The lower body 540 may be manufactured integrally with the upper body 520 to extend down into the upper body 520, or may be attached to the upper body 520 after being manufactured separately from the upper body 520. The volume of the protective part 500 is smaller than or equal to the space formed between the upper surface 122 of the outer tube and the upper body 520 of the protective part than the space between the inner tube 140 and the side surface 124 of the outer tube. It is formed to.

The process gas flowing from the lower part to the upper part of the inner tube 140 passes through the space between the protrusions 522 formed in the upper body 520 of the protective part, and then the upper body 520 of the protective part and the upper surface 122 of the outer tube. It flows through the space between and the space between the inner tube 140 and the side surface 124 of the outer tube, and is exhausted to the outside through the exhaust pipe 280. At this time, since the process gas is rapidly moved in the space between the upper body 520 of the protection unit and the upper surface 122 of the outer tube, the amount of process gas deposited on the upper surface 122 of the outer tube is very small compared to the general apparatus. .

4 is a cross-sectional view of the low pressure chemical vapor deposition apparatus 10 'according to another embodiment of the present invention, and FIGS. 5A and 5B are front and plan views of the protection part 500' of FIG. The protection part 500 'is placed on the top plate 312 of the boat, unlike the embodiment described above. The lower body 540 'has a cylindrical shape having the same lower surface as the upper plate 312 of the boat, and the upper body 520' has a shape projecting to round upwards like the upper surface 122 of the outer tube. The lower surface of the upper body 520 'has the same size as the lower surface of the lower body 540'. The lower surface of the lower body 540 ′ may be provided with a plurality of protrusions 542 protruding downward and placed on the top plate 312 of the boat.

In the device of the present invention, since the protective part 500 'is disposed between the upper surface 122 of the outer tube and the upper plate 312 of the boat, the process gas is directly below the upper surface 122 of the outer tube. Compared to the flow faster, this reduces the amount of process gas deposited on the upper surface 122 of the outer tube.

According to the present invention, it is possible to significantly reduce the amount of process gas deposited on the upper surface of the outer tube, thereby preventing the outer tube from being damaged due to cracks.

Claims (4)

In the low pressure chemical vapor deposition apparatus used in the manufacture of semiconductor devices, A flange having at least one gas inlet and a gas outlet; A cylindrical inner tube supported by the flange and having upper and lower openings; An outer tube supported by the flange and surrounding the outer circumference of the inner tube at a distance from the inner tube, and having an open lower part and an upper part of which is convex; A boat which is movable into the inner tube and mounts a plurality of semiconductor substrates; And Low pressure chemical vapor deposition apparatus characterized in that it comprises a protection portion located between the upper surface of the outer tube and the top plate of the boat to minimize the space formed below the upper surface of the outer tube. The method of claim 1, The protection unit, An upper body having a convexly rounded shape upward; Low pressure chemical vapor deposition apparatus is coupled to the lower portion of the upper body, having a lower body formed in a flat plate shape. The method of claim 2, The upper body protrudes downward from the lower edge of the lower body, and has protrusions placed on the upper sidewall of the inner tube, The lower body has a low pressure chemical vapor deposition apparatus, characterized in that having a cylindrical shape of the same size as the upper plate of the boat. The method of claim 2, The lower body protrudes downward, low pressure chemical vapor deposition apparatus characterized in that it has protrusions that are placed on the upper plate of the boat.