JPS6339960Y2 - - Google Patents

Description

[Detailed description of the invention] This invention is mainly used in semiconductor vapor phase generation equipment (CVD equipment), plasma CVD equipment, plasma etcher, etc. to coat the surface of semiconductor substrates (wafers) by vapor phase thermochemical reactions under reduced pressure conditions. The present invention relates to a filter used in a semiconductor vapor phase processing apparatus that performs processing such as etching.

Among gas phase generation devices (hereinafter referred to as CVD devices), reduced pressure CVD devices are popular because they are easier to mass produce and have better uniformity in film thickness, etc., than normal pressure types. Also, in recent years,
Plasma CVD equipment is becoming popular due to its advantage of lowering the generation temperature, and plasma etchers are becoming popular with the aim of improving the precision of the etching process.
All of these devices use a vacuum pump to maintain the pressure in the reaction chamber suitable for processing the semiconductor substrate, and then introduce a gas suitable for processing the semiconductor substrate inside the reaction chamber to cause a thermochemical reaction. They have in common that they are treated in a vapor phase. 100% of the introduced gas is not used for processing, and some of the gas remains as raw gas or undergoes a chemical reaction in the reaction chamber space and becomes fine powder, which is sucked and exhausted by a vacuum pump, and some of it is This gas is adsorbed on the outer tube wall and other surfaces, forming powder or crystalline precipitates. This precipitate is extremely unstable, and is peeled off by the flow of gas suctioned by the pump and by friction and vibration when the boat moves in and out, and is eventually sucked into the pump.

On the other hand, the pressure range (0.01
Vacuum pumps that can be used at temperatures up to 10 Torr are mainly mechanical pumps such as oil rotary vacuum pumps (rotary pumps) and mechanical booster pumps.
Therefore, suction of precipitates such as powder deteriorates the lubricating oil, damages the sliding parts, blocks the lubricating oil supply port and causes poor lubrication, and fatally shortens the life of the pump. In such cases, the advantage of mass productivity could be lost due to downtime for pump maintenance. Attempts have been made to extend pump life and ease maintenance. The main ones are a device that extends the oil deterioration time by connecting an oil tank to a rotary pump via piping to circulate the oil, and a filter and oil circulation pump installed in the middle of the piping of this device. , a relatively large amount of oil is introduced into the cylinder of a rotary pump by using a device that filters the oil and removes mixed powder, and by using the time that is not used for gas phase treatment.
This is a device that uses the rotation of the pump itself to clean foreign matter inside the cylinder. These are measures against foreign matter that has been sucked into the pump, and are not measures to reduce the amount sucked into the pump.

A filter can be installed in front of the pump to prevent the inhalation of foreign substances, but the pressure conditions for good vacuum gas phase treatment are very delicate, and it is necessary to prevent the passage of the fine powder products mentioned above. Even if a dense filter is provided to prevent this, in extreme cases, clogging may occur within a single processing step, resulting in changes in pressure conditions, making it impossible to perform stable processing. If the filter is made coarser so that it can be used over several processing steps, both the filter must be cleaned or replaced and the pump maintained in a relatively short period of time, which ultimately reduces the amount of maintenance and inspection required. will increase. Therefore, the current situation is to install a filter with a mesh that is coarse enough to block the crystallized coarse solid products in front of the pump, and as a result, the various countermeasures for rotary pumps described above It can be said that this is being carried out.

However, the effects of fine powder products on pumps that do not use oil for pumping action, such as mechanical booster pumps, cannot be alleviated by the above measures, and even with rotary pumps, it is better to dispose of the powder in advance than to suck up a large amount of powder. It goes without saying that it is more rational to prevent suction.

Therefore, the present invention was developed in view of the above points, and it is an attempt to provide a filter that does not become clogged within a short period of time and can be stably used in a practically sufficient number of gas phase treatment steps. It is something to do. An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A. 1 is a first curved pipe having an inlet side pipe end 2 connected to a reaction chamber of a semiconductor vapor phase processing apparatus by an inlet side flange 2a;
is the outlet end of the tube. 4 is a second curved pipe having an outlet side pipe end 5 connected to the vacuum pump through an outlet side flange 5a, and 6 is an inlet side pipe end thereof. The outlet side tube end 3 of the first curved tube 1 and the inlet side tube end 6 of the second curved tube 4 have a concentric double tube structure with outer and inner tubes having different diameters.
A desired number of filter cartridges 7 are connected and attached to the double pipe ends of the first and second bent pipes 1 and 4 in an airtight manner so that they can be exchanged. A gas flow path communicating with the second curved pipe 4 is configured through the pipe. The number of filter cartridges 7 to be used, their mounting structure, and the configuration of the gas flow path are not particularly limited, but may be as shown in the figure, for example. That is, the bases of a plurality of clamp rods 8 having a length determined according to the number of filter cartridges 7 in use are pivotally attached to the flange 3a provided on the outlet side pipe end 3 of the first bent pipe 1. A required number of filter cartridges 7 and end plates 9 are sequentially connected to the double pipe ends of the second curved pipes 1 and 4 via vacuum sealing O-rings 10, and these are inserted into the clamp fitting grooves of the end plates 9. A clamp nut 12 is screwed onto the threaded end portion 11 of the clamp rod 8 inserted into the clamp rod 9a.

In addition, the filter cartridge 7 has first and second pipe bodies 1 connected to the double pipe ends of the first and second curved pipes 1 and 4.
3, 14, annular mesh plates 15a, 15b fitted between one end and the other end of the first and second tubes 13, 14, respectively; and annular mesh plates 15a, 15b.
Partition mesh plates 16a to 16c axially partition the annular space between the first and second tube bodies 13 and 14 sandwiched between
and a filtering material 17 which is filled in the space partitioned by the partitioning mesh plates 16a to 16c, has an extremely large contact area with gas, and has numerous gas passages.

The flange 3a provided at the outlet end 3 of the first curved pipe 1 is provided with a cooling water passage 18, which cools the entire first and second curved pipes 1, 4 and the filter cartridge 7 to provide gas. to promote condensation and crystallization of the product. In addition, a filter material 17 is provided on the end plate 9.
A viewing window 19 is provided to monitor the clogging state of the filter cartridge 7, so that it is possible to know when to replace or clean the filter cartridge 7. A dust meter may be provided instead of the viewing window 19.

Reference numeral 20 designates a guide ring for attaching the filter cartridge 7 that is fitted to the inner circumference of the flange 3a provided at the outlet end 3 of the first bent pipe 1. Although it also plays a supporting role, it may be constructed integrally with the outlet side pipe end 3. Further, as the filtering material 17, for example, a wire mesh, a curved perforated plate, etc., or a pipe-shaped small piece, etc. can be used, and any of these can be used to prevent the innumerable number of particles from coming into close contact with each other during filling and blocking the gas passage. It forms regular gas passages and has an extremely large contact area with gas, making it ideal for removing powdery and crystalline foreign matter contained in gas.

Since the present invention has the above configuration, the first,
If the inlet side pipe end 2 and the outlet side pipe end 5 of the second curved pipes 1 and 4 are connected to the reaction chamber and the vacuum pump through the inlet side flange 2a and the outlet side flange 5a, respectively, the gas leaving the reaction chamber can be From the first curved pipe 1, it passes through the annular mesh plate 15a on the inlet side fitted between the first and second pipe bodies 13 and 14 of the filter cartridge 7, passes through many passages of the filter medium 17, and has a large surface area. Fine powder and crystal foreign substances contained in the gas are removed by contact with the gas. At this time, if a cooling water passage 18 is provided as shown in the figure and cooling water is passed through it, the first and second bent pipes 1 and 4 and the filter cartridge 7
is cooled to promote gas condensation and product crystallization, improving the foreign matter removal effect. The gas from which the foreign matter has been removed passes through the annular mesh plate 15b on the outlet side, passes through the space between it and the end plate 9, and reaches the second pipe body 14 in the center.
It passes through the inside, passes through the second curved pipe 4, and is sucked and exhausted by a vacuum pump. If the filter cartridge cartridge 7 becomes clogged, loosen the clamp nut 12 and remove the threaded end 11 of the clamp rod 8 from the clamp fitting groove 9a of the end plate 9, then remove the filter cartridge 7 and replace it with a new one, or clean and recycle it. You can then install it again. Note that if the mesh plates 15a and 15b are made coarse, the gas flow will not be obstructed and cleaning and regeneration can be easily performed. Also,
The partition mesh plates 16a to 16c uniformly distribute the filtering material 17 in the annular space, and the first and second pipe bodies 13, 1
Although it is useful for fixing 4 together, there is no problem even if it is not provided.

As is clear from the above explanation, according to the present invention, the filter cartridge can be replaced while the first and second curved pipe sections are connected to the reaction chamber and the vacuum pump, that is, while the connection structure of the vacuum evacuation system is maintained. In addition to being easy to clean and regenerate, the use of a filter material that has an extremely large contact area with gas and countless gas passages prevents clogging from occurring over a long period of time, and prevents the semiconductor substrate from becoming clogged. There are effects such as not impairing mass production of phase processing.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A. 1... First curved pipe, 2... Inlet side pipe end, 2a...
...Inlet side flange, 3...Outlet side pipe end, 3a...
...Flange, 4...Second curved pipe, 5...Outlet side pipe end, 5a...Outlet side flange, 6...Inlet side pipe end, 7...Filter cartridge, 8...Clamp rod, 9... ...End plate, 9a...Clamp fitting groove, 10...O-ring for vacuum sealing, 11...Tip thread, 12...Clamp nut, 13...First tube, 14...Second tube, 15a, 15b...
Annular mesh plate, 16a to 16c... Partition mesh plate, 17
...Filtering material.

Claims (1)

[Scope of utility model registration request] In a filter used between a reaction chamber and a vacuum pump of an apparatus that performs gas phase processing on a semiconductor substrate in the reaction chamber by causing a thermochemical reaction by introducing gas while maintaining the reaction chamber under appropriate reduced pressure with a vacuum pump. , an outlet side tube end of the first curved tube having an inlet side tube end connected to the reaction chamber, and an inlet side tube end of the second curved tube having an outlet side tube end connected to the vacuum pump. It has a concentric double pipe structure with outer and inner pipes having different diameters, and the desired number of filter cartridges are connected and installed in an airtight and replaceable manner at the double pipe ends of the first and second curved pipes. , and constitutes a gas flow path communicating from the first curved pipe to the second curved pipe through the filter cartridge, and the filter cartridge has a first pipe connected to the double pipe ends of the first and second curved pipes.
a second tube, an annular mesh plate fitted between one end and the other end of the first and second tubes;
The filter material is filled in the annular space between the first and second tubes sandwiched between two annular mesh plates, has an extremely large contact area with gas, and has numerous gas passages. A filter for semiconductor vapor phase processing equipment.