JPH05152218A - Surface treatment equipment - Google Patents

Abstract

PURPOSE:To form a film equally by spraying a treating gas against a body to be treated with uniform concentration and a uniform flow. CONSTITUTION:Three parting plates 32, 34, 36 are disposed inside a gas chamber 24 at regular intervals in the vertical direction, and gas-flow control chambers 44, 46, 48 at three stages having approximately the same flow-path area are parted. WF6, N2 gas and H2 gas introduced into a gas introducing chamber 26 from gas supply pipes 2g, 30 are introduced together into the gas-flow control chamber 44 at an uppermost stage, and mixed uniformly in the chamber 44. A mixed treating gas (WF6, N2, H2) is admitted into the gas-flow control chamber 46 at an intermediate stage, the flow of the gas is regulated into a gas flow having equal concentration and an equal flow in the radial direction by the second parting plate 34 as the bottom of the chamber 46, and the gas is passed through the gas-flow control chamber 48 at a lower stage at a comparatively fast flow rate, and sprayed against a semiconductor wafer 12 as a fine gas flow from each vent hole 36a of the third parting plate 36.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for spraying a processing gas onto an object to be processed to perform a predetermined surface treatment.

[0002]

2. Description of the Related Art CVD (Chemical Vapor Deposition) is a technique in which a predetermined source gas is supplied to the surface of an object to be processed and its decomposition or reaction product is deposited on the surface of the object to be processed to form a film. .. In order to form a uniform film in CVD, it is necessary to uniformly distribute the source gas over the entire surface of the object to be processed.

In a general single-wafer CVD apparatus, as shown in FIG. 5, an object to be processed, for example, a semiconductor wafer 104 is arranged in the lower center of a processing chamber 102 in a processing container 100, and the semiconductor wafer 104 is heated. While heating from the back side by 106, the source gas is blown onto the surface of the semiconductor wafer 104 from directly above through the porous plate 108.

The perforated plate 108 is a disk having a diameter slightly larger than that of the semiconductor wafer 104 and provided with a large number of ventilation holes 108a. The gas chamber 11 is divided from the processing chamber 102.
It is attached to the lower gas outlet 110a of 0. A raw material gas to be a constituent element of film formation is supplied to a gas introduction chamber 112 communicating with the upper part of the gas chamber 110 from a gas supply source (not shown) via gas supply pipes 114 and 116.

For example, when forming a tungsten film, WF6 gas diluted to a predetermined concentration with a carrier gas (eg, N2 gas) is supplied from one gas supply pipe 114 at a predetermined flow rate, and the other gas supply pipe is supplied. H2 gas having a predetermined concentration is supplied from 116 at a predetermined flow rate.

WF6 and N2 supplied from the gas supply pipes 114 and 116 to the gas introduction chamber 112 having a relatively small flow passage area.
The gas and the H2 gas are guided from there to the gas chamber 110 having a large flow passage area, and mixed with each other in the chamber. Then, each vent hole 10 of the perforated plate 108 at the gas chamber outlet 110a
From 8a, the mixed source gas (WF6, N2, H2) is blown out toward the wafer 104 directly below.

Even in a general single-wafer type plasma etching apparatus, an etching gas such as CF4 is blown to the object to be processed by using a gas chamber and a perforated plate similar to those in the above-mentioned single-wafer type CVD apparatus. I have to.

[0008]

As described above, in the conventional single-wafer CVD apparatus, plasma etching apparatus, etc., the processing gas is distributed from the gas chamber 110 so as to be uniformly distributed over the entire surface of the object to be processed. The processing gas is blown through the perforated plate 108.

However, in the conventional device, the perforated plate 10 is used.
There was a risk that the processing gas would not be blown out as a uniform flow (laminar flow) from each of the ventilation holes 108a of No. 8 and a vortex would be generated.
Further, in the case of using a plurality of processing gases like CVD, in the conventional apparatus, the plurality of processing gases are blown out from the respective ventilation holes 108a of the perforated plate 108 at a non-uniform concentration without being mixed well in the gas chamber 110. There was something.

In the conventional apparatus, when the processing gas enters the gas chamber 110 having a large flow passage area through the gas inlet 112 having a relatively small flow passage area, the flow of the processing gas is diffused and disturbed in the horizontal direction, and the porous gas is left as it is. Each ventilation hole 108a of the plate 108
It is thought that vortices will be generated because they come out more. Also,
Although the processing gas flows into the gas introduction chamber with a considerable force from the gas supply pipe, in the conventional apparatus, the processing gas flowing into the gas introduction chamber 112 immediately blows out from the perforated plate 108 with the same force, which is also a vortex. It is considered to be one of the causes of the generation, and moreover, it is considered to be the cause of the poor mixing of a plurality of process gases.

As described above, in the conventional apparatus, it is difficult to uniformly blow a plurality of completely mixed processing gases over the entire surface of the object to be processed, and it is difficult to form a uniform film.

The present invention has been made in view of the above problems, and an object thereof is to provide a processing apparatus for spraying a processing gas with a uniform concentration and a uniform flow onto an object to be processed to form a uniform film. To do.

[0013]

In order to achieve the above object, the processing apparatus of the present invention introduces a processing gas from a gas supply pipe into a gas chamber defined within a processing container, and from an outlet of the gas chamber. In the processing apparatus in which the processing gas is blown toward the object to be processed, a plurality of partition plates each provided with a large number of vent holes are arranged in the gas chamber at predetermined intervals in the gas flow direction. It is configured as follows.

[0014]

In the present invention, the processing gas flowing in from the gas supply pipe is temporarily blocked by the first partition plate of the gas chamber and then flows out to the second partition plate side. When a plurality of processing gases are supplied, the processing gases move and collide in the first chamber defined by the first partition plate and are mixed with each other. For example, when the gas chamber has a cylindrical shape, the second partition plate has ventilation holes having a pattern of uniform density in the radial direction on the axis, and the processing gas from the first partition plate side is uniformly distributed in the radial direction. Rectify the flow (laminar flow). As a result, the processing gas is blown out from the second partition plate with a uniform concentration and a uniform flow. By disposing the third partition plate, in which the smaller vent holes are provided at high density, on the downstream side of the second partition plate, the gas flow can be finely blasted onto the object to be processed.

[0015]

Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a single-wafer CV according to an embodiment of the present invention.
FIG. 2 is a vertical cross-sectional view showing the configuration of the D device, and FIGS. 2 to 4 are plan views showing the vent hole patterns of the first, second, and third partition plates in the CVD device of the embodiment, respectively.

In FIG. 1, the single-wafer CVD of this embodiment is performed.
The apparatus has a cylindrical processing container 10 made of, for example, aluminum, and a semiconductor wafer 12 as an object to be processed is arranged in the center of the processing container 10. This CVD
In the apparatus, the quartz plate 14 is used as a susceptor (wafer mounting table).
To use. The quartz plate 14 is a support plate 1 having a bottomed cylindrical shape.
The semiconductor wafer 12 is mounted on the quartz plate 14 by being attached to the circular opening 16a of the six. The back surface of the quartz plate 14 faces a heating halogen lamp 22 installed outside the processing container 10 via a quartz plate 20 attached to a circular opening 10a in the center of the bottom surface of the processing container 10. During the film forming process, the light from the halogen lamp 22 passes through the quartz plate 20, further passes through the quartz plate 14, and enters the back surface of the semiconductor wafer 12 to heat the semiconductor wafer 12.

A circular opening 1 is formed in the center of the upper surface of the processing container 10.
0b is provided, and the bottomed cylindrical gas chamber 24 is vertically attached so as to close the opening 10b. The gas chamber 24 is made of a material having a high thermal conductivity, for example, a copper alloy, has an annular mounting flange 24a at the upper end peripheral portion, and is provided with an annular water passage 24b for flowing cooling water therein. It is partitioned from the processing chamber 11 in the container 10. A large vent hole 24c for introducing gas is provided in the central portion of the upper surface of the gas chamber 24, and a gas introduction chamber 26 is connected and mounted on the vent hole 24c. Two gas supply pipes are provided in the gas introduction chamber 26. The gas discharge ports of 28 and 30 are facing.

For example, when a tungsten film is formed on the semiconductor wafer 12 in this CVD apparatus, WF6 gas diluted with N2 gas to a predetermined concentration is supplied from one gas supply pipe 28 at a predetermined flow rate. H2 gas is supplied from the other gas supply pipe 30 at a predetermined flow rate.

Inside the gas chamber 24, three partition plates 32, 34, 36 are horizontally mounted at a predetermined interval in the vertical direction. First partition plate 32 at the top
Is, for example, an aluminum plate having a plate thickness of 20 mm and having a large number of holes, for example 153 holes, in the plate surface in a pattern as shown in FIG. It is arranged at a position 20 mm below, for example, from the inner upper surface through the spacer 38. The middle second partition plate 34 has a plate thickness of, for example, 10 mm, and has a large number of, for example, 2 on the plate surface in a pattern as shown in FIG.
52 holes, circular shape, for example, ventilation hole 34 with a diameter of 0.7 mm
It is an aluminum plate provided with a and is arranged at a position, for example, 20 mm below from the lower surface of the first partition plate 32 via the spacer 40. The third partition plate 36 in the lowermost stage has a plate thickness of, for example, 3 mm, and is provided with a large number of 1740 holes on the plate surface in a pattern as shown in FIG. An aluminum plate from the lower surface of the second partition plate 34, for example, 20 mm
It is arranged on the lower surface of the gas chamber 24 at a lower position. These 3
Step partition plates 32, 34, 36 and spacers 38, 4
0, three stages of gas flow control chambers 44, 46, 48 each having an appropriate flow passage area are defined in the gas chamber 24.

Outside the gas chamber 24, heat insulating spacers 50 and 54 are provided between the gas chamber 24 and the upper surface of the processing container 10 and between the upper surface of the gas chamber 24 and the gas introduction chamber 26, respectively. Is provided.

Next, the operation of the CVD apparatus having such a structure will be described. During the film forming process, the halogen lamp 22 below the semiconductor wafer 12 placed on the quartz susceptor 14 is used.
While heating the wafer 12 with more light energy, the mixed process gas (WF6, N2, H2) is supplied from the upper gas chamber 24.
Is sprayed on the wafer 12. Gas generated in the film forming process and excess processing gas are sent to a removing device (not shown) from an exhaust port 56 provided on the bottom surface of the processing container 10 via a gas exhaust pipe. Desirably, four or more exhaust ports 56 are provided so that the processing gas is uniformly exhausted to the circumference of the wafer 12.

In the present CVD apparatus, the gas supply pipe 28,
The WF6, N2 gas and H2 gas introduced into the gas introduction chamber 26 from 30 are introduced together from the gas introduction chamber 26 to the uppermost gas flow control chamber 44 of the gas chamber 24, where they are uniformly mixed. .. That is, since the first partition plate 32 provided at the bottom of the gas flow control chamber 44 has a large plate thickness and a small aperture ratio, it has a low conductance and a large differential pressure with the gas flow control chamber 46. Cause This allows
The WF6, N2 gas, and H2 gas that have entered vigorously from the gas introduction chamber 26 move and collide in the gas flow control chamber 44 so that they are once blocked, and mix well with each other. Thus, the uppermost gas flow control chamber 44 and the first gas flow control chamber 44
The partition plate 32 has a buffer function for uniformly mixing the processing gas. Since the ventilation holes 32a of the first partition plate 32 are distributed in a grid pattern as shown in FIG. 2, the mixed processing gas (WF6, N2) having a constant flow rate and concentration per unit area from each ventilation hole 32a is formed. , H2) is discharged to the gas flow control chamber 46 side in the middle stage.

The mixed processing gas (WF6, N2, H2) that has entered the middle gas flow control chamber 46 is a gas of uniform concentration and uniform flow in the radial direction by the second partition plate 34 at the bottom of this chamber 46. It is rectified into the flow. That is, since the ventilation holes 34a of the second partition plate 34 are distributed symmetrically in the radial direction on the axis as shown in FIG. 3, the mixed processing gas (WF6, N2) in the cylindrical gas chamber 24 is formed. , H2) concentration and flow are homogenized radially in axial symmetry. In this way, the middle gas flow control chamber 46 and the second partition plate 3 are
4 has a gas flow rectification function. Since the plate thickness of the second partition plate 34 is also relatively large, there is some buffer effect in the gas flow control chamber 46, and the mixing degree of the mixed process gas (WF6, N2, H2) is further strengthened here.

The mixed process gas (WF6, N2, H2) discharged from the middle gas flow control chamber 46 is the lower gas flow control chamber 48.
Through the vent holes 36a of the third partition plate 36 with a more uniform flow and a more uniform concentration, and the water is poured evenly over the entire surface of the semiconductor wafer 12 immediately below. Since the third partition plate 36 is a thin plate and has a large aperture ratio, it has a large conductance, and since the ventilation holes 36a are small holes and have a high density, the gas flow of the mixed processing gas (WF6, N2, H2) becomes fine. .. In this way, the lower gas flow control chamber 48 and the third partition plate 36 have a gas flow subdivision function.

However, the ventilation holes 3 of the second partition plate 34
It is possible to omit the third partition plate 36 and the lower gas flow control chamber 48 by decreasing the diameter of 6a and increasing the density. Further, the first partition plate 32 can also be configured by a porous ceramic plate, a metal particle sheet, or the like, and the ventilation hole pattern of the first partition plate 32 has the same axis symmetry as the second partition plate 34. It is also possible to use a pattern of. In addition, it is possible to select any pattern as the ventilation hole pattern of each partition plate if necessary, and also select the plate thickness and the mounting interval of each partition plate to any thickness and interval. You can Further, the diameter and the number of ventilation holes can be arbitrarily selected.
The gas flow control chamber may be filled with beads, glass wool, or the like.

Further, although two processing gases are introduced in the above-mentioned embodiment, one processing gas may be introduced, and the present invention is not limited to the CVD apparatus and other surface treatments such as a plasma etching apparatus. It is also applicable to devices.

[0027]

As described above, according to the processing apparatus of the present invention, a plurality of partition plates each having a large number of ventilation holes are provided in the gas flow direction in the gas chamber for receiving the processing gas from the gas supply pipe. By disposing the treatment gas at a predetermined interval, it is possible to blow the processing gas to the object to be processed with a uniform concentration and a uniform flow, and it is possible to form a uniform film on the object to be processed.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing the structure of a single-wafer CVD apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a vent hole pattern of a first partition plate in the CVD apparatus of the embodiment.

FIG. 3 is a plan view showing a vent hole pattern of a second partition plate in the CVD apparatus of the embodiment.

FIG. 4 is a plan view showing a vent hole pattern of a third partition plate in the CVD apparatus of the embodiment.

FIG. 5 is a vertical cross-sectional view showing the configuration of a conventional typical single-wafer CVD apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Processing container 12 Object to be processed (semiconductor wafer) 24 Gas chamber 26 Gas introduction chamber 28 Gas supply pipe 30 Gas supply pipe 32 First partition plate 34 Second partition plate 36 Third partition plate 44 First gas flow Control room 46 Second gas flow control room 48 Third gas flow control room

Claims (1)

[Claims] 1. A surface treatment apparatus in which a processing gas from a gas supply pipe is introduced into a gas chamber defined in a processing container, and the processing gas is blown toward an object to be processed from an outlet of the gas chamber. A surface treatment apparatus, characterized in that a plurality of partition plates each having a large number of ventilation holes are arranged in the gas chamber at predetermined intervals in the gas flow direction.