JP2000173927A - Parallel plate type cvd film formation equipment and method of forming the film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a parallel plate type CVD film formation equipment which can prevent generation of particles due to the peeling of a CVD film. SOLUTION: This CVD film formation equipment has, in a reaction chamber, an upper parallel plate 60 having a hollow part 38 inside, a lower parallel plate 28 which is located below the upper plate face to face with it to be mounted with a wafer, and a lifter 30 for moving the lower plate up and down against the upper one. The upper plate is provided with a first gas inlet 36 and a second gas inlet 62, both being formed on an upper face of the plate, and a shower head 64 extended over almost the entire surface of a lower face. The shower head has partition walls 74 for separating a peripheral region from a central region. A first cleaning gas is let in through the first gas inlet and is passed through the hollow part to be diffused from the central region of the shower head. The second gas inlet is connected to a gas lead-in pipe 66 which is passed through the hollow part and has a gas outlet 68 in the peripheral region of the shower head. A second cleaning gas which is different in composition from the first gas is introduced through the second gas inlet and is diffused into the reaction chamber from the peripheral region of the shower head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a parallel plate type CVD.
The present invention relates to a film forming apparatus and a method of forming a CVD film, and more particularly to a parallel plate type CVD film forming apparatus and a method of forming a CVD film which prevent generation of particles due to peeling of the CVD film.

[0002]

2. Description of the Related Art There are various types of CVD film forming apparatuses for forming a thin film on a wafer by a CVD method.
Although having features, a parallel plate type CVD film forming apparatus having a relatively simple structure and easy operation is widely used as one of the CVD film forming apparatuses.

Here, the configuration of a conventional parallel plate type CVD film forming apparatus will be described with reference to FIGS. FIG. 4 shows C
FIG. 5 is a plan view illustrating the overall configuration of a VD film forming apparatus, FIG. 5 is a schematic cross-sectional view illustrating the structure of a reaction chamber of a conventional parallel plate type CVD film forming apparatus, and FIG. 6 is a structure of an upper parallel plate and a lower parallel plate. FIG. 7A is a perspective view of a shower head, and FIG. 7B is a plan view of the shower head. The conventional CVD film forming apparatus 10 uses a CV
A reaction chamber 12 for forming a D film, a load lock chamber 16 communicating with the reaction chamber 12 via a first gate valve 14 and having a wafer transfer robot 15, and a wafer adjacent to the load lock chamber 12. It has a positioning chamber 18 and a second gate valve 20 provided at a wafer loading / unloading port of the load lock chamber 16. The wafer positioning chamber 18 is a room for adjusting the direction of the wafer to be fed into the reaction chamber 12 with reference to the orientation flat of the wafer. The cassette 22 containing the wafer W is disposed in front of the load lock chamber 12 via the second gate valve 20.

As shown in FIG. 5, the reaction chamber 12 has a chamber 24 having an opening communicating with the load lock chamber 16 via a first gate valve 14 on one of the side walls, and an upper portion in the chamber 24. Upper parallel flat plate 26, and a lower parallel flat plate 28, which is paired with the upper parallel flat plate 26, is disposed below and opposed to the upper parallel flat plate 26, and has a wafer mounted thereon.
And a lifter 30 for raising and lowering the lower parallel plate 28 toward the upper parallel plate 26. In addition, a reaction chamber 12 is provided on a side wall of the reaction chamber 12 opposite to the first gate valve 14.
The exhaust system is connected to a vacuum pump (not shown), an exhaust pipe 32 connecting the vacuum pump to the reaction chamber 12, and an APC device 34 ( Automatic pressure control device for the reaction chamber 12). Reaction chamber 1 through the internal hollow portion of parallel plate 26
The gas inlet 36 for introducing the gas into the upper parallel plate 26
Is provided on the upper surface.

[0005] As shown in FIG.
The inside is a hollow plate-shaped electrode, which has a gas inlet 36 at the upper center, and a baffle plate 40 at a position facing the gas inlet 36 in the hollow portion 38 inside, and a shower below the baffle plate 40. A head 42 is provided to allow gas to flow out while being dispersed. The gas inlet 36 includes a reaction gas inlet 44 for introducing a film forming reaction gas, an inert gas inlet 46 for introducing an inert gas, and a cleaning gas inlet 48 for introducing a cleaning gas. As shown in FIGS. 7A and 7B, the shower head 42 has a large number of gas outlet holes 50 formed in a dish-shaped curved plate formed of a part of a spherical surface.
As shown in FIG. 7, the gas outlet holes 50 have a substantially uniform distribution. The lower parallel plate 28
As shown in FIG. 6, the wafer W is housed in a central recess with the film-forming surface thereof facing upward.

The gas introduced from the gas inlet 36 collides with the baffle plate 40 and is uniformly dispersed toward the periphery of the hollow portion 38, and passes between the side wall of the chamber 24 and the outer edge of the baffle plate 40 to shower. Head to the head 42, the shower head 42
Impacts the wafer in a uniform distribution through a number of gas outlet holes 50, and then is exhausted from chamber 24 by an exhaust system.

Referring to FIGS. 4 to 6, a conventional CVD method for forming a CVD film using the above-mentioned parallel plate type CVD film forming apparatus 10 (hereinafter, referred to as CVD film forming apparatus 10) will be described. The film method will be described. (1) The second of the load lock chamber 16 of the CVD film forming apparatus 10
A cassette 22 accommodating a Si wafer is set in front of the gate valve 20 of FIG. (2) First, the second gate valve 20 is opened, and the wafer W is loaded into the load lock chamber 15. (3) A vacuum pump (not shown) dedicated to the load lock chamber 12 is activated to reduce the pressure in the load lock chamber 12 to the reaction chamber 1.
Vacuum suction is performed so that the pressure becomes almost the same as the pressure in 2. (4) After the load lock chamber 12 is evacuated to a reduced pressure, the orientation flat of the wafer W is aligned in the wafer alignment chamber 18.

(5) Open the first gate valve 14,
The wafer W is transferred into the reaction chamber 12 by the transfer robot 15. The wafer W is placed on the lower parallel flat plate 28 in the reaction chamber 12, as shown in FIG. (6) The pressure in the reaction chamber 12 is increased by a CVD film, for example, metal C.
The pressure is adjusted to a pressure suitable for the formation of the VD film, and a reaction gas is flown into the reaction chamber 12 to form a CVD film on the wafer W. (7) After the formation of the CVD film, the inside of the reaction chamber 12 is evacuated by an exhaust system. (8) In order to completely remove the reaction gas in the reaction chamber 12, an inert gas is introduced from the inert gas inlet 46 to purge the inside of the reaction chamber 12.

(9) The inside of the reaction chamber 12 is evacuated again,
The pressure is made the same as that of the load lock chamber 16. (10) Open the first gate valve 14 and set the reaction chamber 1
Then, the wafer W is unloaded from the load lock chamber 16 to the load lock chamber 16. (11) The inside of the load lock chamber 16 is brought to the same pressure as the atmospheric pressure by introducing an inert gas into the load lock chamber 16. (12) Unload the wafer W from the load lock chamber 16,
Collected in cassette 22. (13) In the process of forming a metal CVD film on a wafer in the reaction chamber 12, a film is simultaneously generated and adhered to the side wall of the reaction chamber 12. Therefore, the CV of at least one wafer
Each time the D film is formed, a cleaning gas is introduced into the reaction chamber 12 from the cleaning gas inlet 48, and the reaction chamber 1
2. Remove the deposits on the side walls of No. 2. Thus, the step of forming a CVD film on one wafer is completed.

Incidentally, the above-mentioned conventional parallel plate type CV
In the D film forming apparatus, as shown in FIG. 8, the CVD film is formed not only on the upper surface of the wafer but also on the side surface, but not on the back surface of the wafer. For this reason, there is a problem that the CVD film is peeled off due to various impacts applied to the side surface of the wafer when the wafer is transferred. In particular, in a metal-based CVD film having a large stress, the phenomenon of film peeling was remarkable. When the film is peeled off, particles are generated and often hinder the subsequent process.

Therefore, conventionally, the following method has been adopted in order to prevent this film peeling. That is, after a resist film is formed on the entire surface of the wafer, only the resist film at the peripheral portion of the wafer is removed using a photolithography process to expose the CVD film at the peripheral portion of the wafer, and then the exposed CVD film at the peripheral portion of the wafer. Is removed by a dry etching apparatus. As described above, by previously removing the CVD film in the peripheral portion of the wafer that causes the film peeling,
Conventionally, a method for preventing the occurrence of film peeling of a CVD film has been adopted.

[0012]

However, the above-mentioned conventional method for preventing film peeling requires processing by several devices between the CVD film forming step and the dry etching step. There has been a problem that peeling occurs and causes generation of particles. In addition, in the photolithography process and the dry etching process, it is necessary to use an exposure apparatus and a dry etching apparatus, respectively.
There is a problem that it is difficult to economically form a CVD film.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a parallel plate type CVD film forming apparatus and a method of forming a CVD film which prevent generation of particles due to peeling of the CVD film.

[0014]

In order to achieve the above object, a parallel plate type CVD film forming apparatus according to the present invention comprises an upper parallel plate having a hollow portion therein, and a lower plate facing the upper parallel plate. A lower parallel flat plate on which a wafer is placed and a lifter for raising and lowering the lower parallel flat plate toward the upper parallel flat plate are provided in the reaction chamber, and the upper parallel flat plate introduces a gas containing a first cleaning gas. A first gas inlet provided at the center of the upper surface, and a shower head extending over substantially the entire lower surface. The gas is introduced from the gas inlet and dispersed from the shower head via the hollow portion. Parallel plate type CV which is made to flow while flowing
In the D film forming apparatus, the upper parallel plate is connected to the second gas inlet provided separately from the first gas inlet and the second gas inlet, and penetrates through the hollow portion to form a gas into the shower head peripheral region. A second gas inlet pipe having an outlet; and a shower head having a partition partitioning a shower head peripheral area and a shower head central area, and a second gas inlet having a different composition from the first cleaning gas through the second gas inlet. The cleaning gas is introduced.

In the parallel plate type CVD film forming apparatus of the present invention,
After the CVD film is formed on the wafer in the reaction chamber, an inert gas is introduced and flows out from the central region of the shower head,
The reaction chamber is purged to remove reaction gas from the reaction chamber. Next, after the lower parallel plate is brought closer to the upper parallel plate by activating the lifter, while the outflow of the inert gas from the shower head is continued, the first cleaning gas is supplied from the second cleaning gas inlet. A different second cleaning gas is introduced and flows out of the area around the showerhead. Since the wafer central region is maintained at a positive pressure due to the outflow of the inert gas, the second cleaning gas flows along the peripheral portion of the wafer having a low pressure. The film is etched away. Preferably, as the second cleaning gas, an etching gas for etching a CVD film formed on a wafer by a parallel plate type CVD film forming apparatus is introduced.

A method for forming a CVD film according to the present invention is a method for forming a CVD film on a wafer by using the above-mentioned parallel plate type CVD film forming apparatus according to the present invention.
Forming a VD film on the wafer, introducing an inert gas to flow out of the central region of the shower head to purge the reaction chamber, and removing the reaction gas from the reaction chamber; A step of bringing the lower parallel plate closer to the upper parallel plate; and, while keeping the lower parallel plate closer to the upper parallel plate, flowing out the inert gas from the central region of the shower head while maintaining the second cleaning gas inlet. Introducing a second cleaning gas different from the first cleaning gas from the above, and letting it flow out of the peripheral area of the shower head; and, after unloading the wafer from the reaction chamber, introducing the first cleaning gas. Cleaning the chamber wall of the reaction chamber.

[0017]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. Embodiment Example This embodiment is an example of an embodiment of a CVD film forming apparatus according to the present invention, and FIG. 1 shows a main part of the CVD film forming apparatus of this embodiment, that is, a configuration of an upper parallel plate. FIG. 2A is a schematic cross-sectional view, FIG. 2A is a perspective view of a shower head provided on the upper parallel flat plate of this embodiment, and FIG. 2B is a plan view of the shower head. Except for the configuration of the upper parallel flat plate and the shower head, the CVD film forming apparatus of the present embodiment is
It has the same configuration as the conventional CVD film forming apparatus 10 shown in FIGS.

The upper parallel plate 60 provided in the CVD film forming apparatus of this embodiment is different from the upper parallel plate 26 shown in FIG. 6 in addition to the cleaning gas inlet 48 as shown in FIG. Second cleaning gas inlets 62 provided at two locations on the upper surface of the upper parallel plate 26 that are opposed to each other.
And a shower head 64 having a different configuration from the conventional shower head 42 shown in FIG. The introduction pipe 66 connected to the second cleaning gas inlet 62 penetrates through the hollow portion 38 in the upper parallel plate 60, and has a gas outlet 68 on the periphery of the shower head 64.

As shown in FIG. 2, the shower head 64 has a cylindrical partition wall 74 for dividing the shower head peripheral region 70 from the shower head central region 72 in addition to the structure of the conventional shower head 42 shown in FIG. Have.
A large number of gas outlet holes 50 are provided in the shower head peripheral region 70 and the shower head central region 74 with a uniform distribution similarly to the conventional shower head 42.

Next, a method for forming a CVD film using the CVD film forming apparatus of the embodiment will be described with reference to FIGS. First, a CVD film is formed on a wafer in the reaction chamber 12 in the same procedure as the above-described conventional film forming method. (1) After the completion of the CVD film formation, an inert gas, for example, a nitrogen gas is introduced from the inert gas inlet 46 to purge the inside of the reaction chamber 12 in order to completely remove the reaction gas in the reaction chamber 12. I do. (2) Next, the lifter 30 is activated to activate the lower parallel plate 28.
Close to the upper parallel plate 60, and make the distance at most 1 m.
m or less. (3) Next, a second cleaning gas different from the first cleaning gas is introduced from the second cleaning gas inlet 62 while the inert gas flows out from the central region 72 of the shower head 64, The water flows out from the peripheral area 70 of the shower head 64. At this time, the wafer central region has a positive pressure due to the outflow of the inert gas, and the second cleaning gas flows along the peripheral portion of the wafer having a low pressure and flows into the central region of the wafer having a high pressure. Nothing happens. Therefore, the second cleaning gas flows along the periphery of the wafer. Thus, the CVD film formed on the peripheral portion of the wafer is removed by etching as shown in FIG.

Thereafter, the wafer W is unloaded from the reaction chamber 12 in the same manner as in the conventional film forming method described above, and then the reaction chamber 12 is cleaned with a first cleaning gas. In the present embodiment, since the second cleaning gas has already been introduced for removing the CVD film in the peripheral portion of the wafer, the wall surface of the chamber 24 of the reaction chamber 12 is considerably cleaned by this. The amount of the first cleaning gas to be introduced is small, and the cleaning time is short.

[0022]

According to the present invention, CVD of a peripheral portion of a wafer is performed.
Since the film is removed in advance in the reaction chamber, generation of particles due to peeling of the CVD film is suppressed. In addition, before the wafer is unloaded from the reaction chamber, the CVD film adhering to the side wall of the reaction chamber is also removed by the second cleaning gas, so that generation of particles can be minimized. In addition, the method of the present invention can remove the CVD film at the peripheral portion of the wafer by a much easier and simple process than the conventional method of removing the CVD film at the peripheral portion of the wafer by photolithography and etching.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing a main part of a CVD film forming apparatus according to an embodiment, that is, a configuration of an upper parallel plate.

FIG. 2A is a perspective view of a shower head provided on an upper parallel flat plate of the CVD film forming apparatus of the embodiment, and FIG.
(B) is a plan view of the shower head.

FIG. 3 shows a CVD film formed by the CVD film forming apparatus of the embodiment.
It is a wafer sectional view showing the shape of a film.

FIG. 4 is a schematic plan view illustrating an overall configuration of a CVD film forming apparatus.

FIG. 5 is a schematic sectional view showing a structure of a reaction chamber of a conventional parallel plate type CVD film forming apparatus.

FIG. 6 is a schematic sectional view showing the structure of an upper parallel plate and a lower parallel plate provided in a reaction chamber of a conventional parallel plate type CVD film forming apparatus.

FIG. 7A is a perspective view of a shower head, and FIG.
(B) is a plan view of the shower head.

FIG. 8 is a sectional view of a wafer showing a shape of a CVD film formed by a conventional CVD film forming apparatus.

[Explanation of symbols]

10: conventional CVD film forming apparatus, 12: reaction chamber, 14
... First gate valve, 15 Transfer robot, 16
...... Load lock chamber, 18 Wafer alignment chamber, 2
0 ... second gate valve, 22 ... cassette, 24 ...
... chamber, 26 ... upper parallel plate, 28 ... lower parallel plate, 30 ... lifter, 32 ... exhaust pipe, 34 ... A
PC device, 36 gas inlet, 38 hollow part, 40
... baffle plate, 42 ... shower head, 44 ... reactive gas inlet, 46 ... inert gas inlet, 48 ... cleaning gas inlet, 50 ... gas outlet hole, 60 ... CVD film formation of the embodiment Upper parallel plate provided on the device, 62... Second
Cleaning gas inlet, 64 ... shower head,
66 ... introduction pipe, 68 ... gas outlet, 70 ... showerhead peripheral area, 72 ... showerhead central area, 7
4. Partition wall.

Claims (4)

[Claims] An upper parallel plate having a hollow portion therein;
A lower parallel plate, which is disposed below and opposed to the upper parallel plate, on which a wafer is placed, and a lifter, which raises and lowers the lower parallel plate toward the upper parallel plate, is provided in the reaction chamber. A first gas inlet provided at the center of the upper surface for introducing a gas containing a cleaning gas of
And a shower head extending over substantially the entire lower surface, wherein a gas is introduced from a gas inlet, and is allowed to flow out from the shower head through a hollow portion while being dispersed from the shower head. The upper parallel plate is connected to the second gas inlet provided separately from the first gas inlet, and the second gas inlet, and has a gas outlet penetrating through the hollow portion and having a gas outlet in a peripheral region of the shower head. A second cleaning gas having a composition different from that of the first cleaning gas through a second gas inlet; A parallel plate type CVD film forming apparatus characterized by being introduced. 2. The parallel plate type etching apparatus according to claim 1, wherein the second cleaning gas is an etching gas for etching a CVD film formed on a wafer by a parallel plate type CVD film forming apparatus. CVD film forming equipment. 3. The parallel plate type CV according to claim 1 or 2.
A method of forming a CVD film on a wafer using a D film forming apparatus, comprising the steps of forming a CVD film on a wafer in a reaction chamber, and introducing an inert gas to flow out of a central region of a shower head. Purging the reaction chamber to remove the reaction gas from the reaction chamber, starting the lifter to bring the lower parallel plate closer to the upper parallel plate, and bringing the lower parallel plate closer to the upper parallel plate. A second cleaning gas different from the first cleaning gas is introduced from the second cleaning gas inlet while continuing the outflow of the inert gas from the central region of the shower head, and from the peripheral region of the shower head. A step of introducing a first cleaning gas after the wafer is unloaded from the reaction chamber and cleaning the chamber wall of the reaction chamber. And a method for forming a CVD film. 4. The CVD film according to claim 3, wherein the second cleaning gas is an etching gas for etching a CVD film formed on a wafer by a parallel plate type CVD film forming apparatus. Film formation method.