JP2765371B2 - Film processing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus used for manufacturing a semiconductor device, and more particularly to a film forming apparatus using a reactive gas.

[0002]

2. Description of the Related Art As one of film forming methods using a reactive gas, there is a chemical vapor deposition (hereinafter, referred to as CVD) method. In general, the CVD method uses a gaseous compound as a silicon wafer (hereinafter simply referred to as a wafer).
In the method of conducting a chemical reaction such as decomposition, oxidation, reduction, etc. in a gas or on the surface of a semiconductor substrate in a gas or on the surface of a semiconductor substrate to form a desired fixed thin film on the substrate, depending on the type of gas or the mixing ratio, Various thin films such as an insulating film, a semiconductor thin film, and a conductor thin film can be formed.

[0003] In recent years, mass production and high precision of semiconductor devices have been developed with the development of new methods and materials of CVD technology. However, the development of VLSI for miniaturization and thinning has not been stopped. As the diameter of wafers increases, the demand for CVD technology has also diversified, and various ideas have been devised.

FIG. 8 is a schematic sectional view of a film forming chamber in a conventional plasma CVD apparatus. In the figure, 1 is a chamber for forming a film forming chamber, 2 is a wafer to be processed, 3 is an electrode, a susceptor on which the wafer 2 is mounted, 4 is a gas supply pipe for supplying a reactive gas, and 5 is a gas supply pipe. A blocker plate for equalizing the concentration of the reactive gas supplied from the gas supply pipe 4 in the chamber 1, a counter electrode 6 for the susceptor 3, and a gas supply hole 7 formed in the counter electrode 6. is there.

Next, the plasma C constructed as described above is used.
A film forming method using a VD apparatus will be described with reference to FIG. First, the wafer 2 is placed on the susceptor 3 in the chamber 1. Next, a reactive gas corresponding to the purpose of film formation is supplied into the chamber 1 from the gas supply pipe 4. At this time, the reactive gas is supplied to the blocker plate 5 and the gas supply holes 7
And flows into the chamber 1. Here, high-frequency power is applied between the susceptor 3 and the counter electrode 6 under a pressure of 0.1 to several Torr. The reactive gas is turned into plasma, and a desired film can be deposited on the wafer 2.

[0006]

The conventional film forming apparatus such as CVD is configured as described above. When a film is deposited on the wafer 2, the film is deposited on the inner wall of the chamber 1 other than the wafer 2 or on the counter electrode 6 or the like. The deposited film also adheres. For this reason, an unnecessary deposited film is removed using a cleaning gas (NF ₃ + O ₂ or the like). However, the counter electrode 6 is shown in FIG.
Since the gas supply holes 7 are formed as shown in (a), the deposited film 8 on the side surfaces of the gas supply holes 7 remains without being removed. Further, cleaning residues (compounds containing Al, F, and O) generated by the cleaning gas also adhere to the side surfaces of the gas supply holes 7 and remain as deposited films 8. FIG.
(B) and (c) are a plan view and a cross-sectional view of the gas supply hole 7 in which the deposition film 8 is deposited on the side surface. As shown in FIG.
As a result, the gas supply hole 7 is closed, so that sufficient gas cannot be supplied into the chamber 1. From this,
The deposition rate decreased, and a stable film thickness could not be obtained when forming a film on the wafer 2. Further, in order to form a film having a desired thickness, the counter electrode 6 is formed in order to prevent the gas supply hole 7 from being clogged.
Had to be replaced frequently.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a film forming apparatus capable of stably supplying gas from a counter electrode and forming a stable film on a wafer. The purpose is to:

[0008]

According to a first aspect of the present invention, there is provided a film forming apparatus comprising: a plurality of opposed electrodes each having a plurality of slits formed in parallel with each other and arranged in parallel at predetermined intervals in a gas flow direction; And the slit plates are arranged so that the slit directions of the adjacent slit plates are inclined with respect to each other so that the reactive gas passes between the slit and the slit plate.

A film forming apparatus according to a second aspect of the present invention includes an electrode stabilizer electrically connected to the counter electrode and disposed at a predetermined interval downstream of the gas. A gas supply hole is formed at a position corresponding to a portion of the electrode stabilizer plate occupied by the slits of the respective slit plates in a direction overlapping the gas flow direction.

[0010]

In the film forming apparatus according to the present invention, the opposing electrode is constituted by a plurality of slit plates formed with a plurality of slits parallel to each other and arranged in parallel at a predetermined interval in the gas flow direction. Since the reactive gas is passed between the slit and the slit plate by arranging the slit directions of the plates so as to be inclined to each other, the gas flow can be made uniform, and the deposition film can be deposited on unnecessary portions during film formation. Since the amount of adhesion can be reduced and dispersed, and the gas supply hole can be prevented from being closed, stable gas supply can be always performed.

An electrode stabilizer is provided which is electrically connected to the opposing electrode and is disposed downstream of the gas at a predetermined interval, and the electrode stabilizer has an area occupied by a slit of each slit plate. Since the gas supply holes are formed at positions corresponding to the portions overlapping in the direction of the gas flow, the gas flow can be further smoothed, and stable discharge can be performed, so that a stable film can be formed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. In addition, the description of the part that overlaps with the description of the related art will be appropriately omitted.

Embodiment 1 FIG. FIG. 1 is a sectional view of a film forming chamber in a plasma CVD apparatus according to one embodiment of the present invention. In the figure, reference numerals 1 to 5 are equivalent to the conventional example. Reference numeral 9 denotes a counter electrode for the susceptor 3. Reference numeral 10 denotes a slit plate, and the counter electrode 9 is formed by stacking several slit plates 10. Reference numeral 11 denotes a slit formed in the slit plate 10.

FIG. 2 is a detailed configuration diagram of the counter electrode 9.
As shown in FIG. 2A, a plurality of slits 11 having a slit width 10a and a slit interval 10b are provided in parallel on the slit plate 10, and each slit plate 10 has a direction of the slit 11 between adjacent slit plates 10. Arranged so that they are inclined to each other, and the slit plate interval 1
A plurality of sheets are stacked while maintaining 0c. Further, as shown in FIG. 2B, the slit width 10a is at least larger than the diameter of the conventional gas supply hole 7, for example, 0.7 mmφ. Next, the slit interval 10b is at least larger than the slit width 10a. The slit plate interval 10c is at least larger than the slit width 10a.

Next, the plasma C thus configured
A film forming method using a VD apparatus will be described with reference to FIG. First, the wafer 2 is placed on the susceptor 3 in the chamber 1. Next, a reactive gas according to the purpose of film formation is supplied into the chamber 1 from the gas supply pipe 4. At this time, the reactive gas passes through the blocker plate 5 and then flows into the chamber 1 through the slits 11 of several slit plates 10 of the counter electrode 9. Here, high-frequency power is applied between the susceptor 3 and the counter electrode 9 under a pressure of 0.1 to several Torr. The reactive gas is turned into plasma, and a desired film can be deposited on the wafer 2.

At this time, since the slit plates 10 are arranged so that the directions of the slits 11 are mutually inclined between the adjacent slit plates 10, when the gas is supplied,
In addition to preventing the reactive gas flow, the deposited film 8 as a reaction product can be prevented from returning back through the slit 11 of each slit plate 10 and adhering to the inner wall of the chamber 1 near the gas supply pipe 4. Further, since several slit plates 10 are overlapped to form the counter electrode 9, each slit width 10a can be made larger than the conventional gas supply hole 7, so that the slit width 10a can be prevented from being blocked by the deposited film 8. Further, by making the slit interval 10b larger than the slit width 10a, the deposited film 8 is prevented from returning through the slit 11 and adhering to the inner wall of the chamber 1 near the gas supply pipe 4. Further, the slit plate interval 10c is set to be large enough for the lateral flowability so that the reactive gas flows more uniformly.

As a result, the rate at which the slit 11 is blocked by the unnecessary deposited film 8 in the counter electrode 9 decreases,
Since the gas supply amount is stable, a film can be stably formed on the wafer 2. Further, since the hole clogging rate of the slit 11 due to the deposited film 8 is reduced, the frequency of replacing the counter electrode 9 can be reduced, so that the economic efficiency and the working rate can be improved.

Embodiment 2 FIG. In the first embodiment, the counter electrode 9 has an example in which several slit plates 10 are configured so that the directions of the slits 11 are mutually inclined between the adjacent slit plates 10, as shown in FIG. 3. 11 formed in the slit plate 10 as shown in FIG.
Are 90 degrees between adjacent slit plates 10.
Several slit plates 10 may be overlapped so as to form an inclination angle of degrees. At this time, the cross-sectional shape of the gas passage 12 of the slit 11 in the gas flow direction formed by the plurality of slit plates 10 of the counter electrode 9 is square.

The structure of the counter electrode 9 shown in FIG. 3 is installed below the counter electrode 9 shown in the first embodiment, and
When used in combination with the structure of the counter electrode 9 described above, the amount of deposition of the deposited film on the inner side surface of the gas through passage 12 can be reduced, and the gas can be supplied more stably, and a uniform film can be formed.

Embodiment 3 FIG. Further, in the second embodiment, the example in which the cross section of the gas passage 12 of the slit 11 has a square shape is shown. However, as shown in FIG. And the cross-sectional shape of the gas passage 12 may be a regular hexagon. In this case, the gas passage 12 is wider than in the case of the second embodiment, so that the clogging of the hole by the deposited film 8 can be further prevented.

Embodiment 4 FIG. In the first embodiment, the slit plates 10 constituting the opposing electrode 9 have the same slit plate interval 10c, but as shown in FIG.
May be gradually narrowed from the lower part to the upper part in the counter electrode 9. This is because the amount of the deposited film 8 gradually decreases from the lower part to the upper part of the counter electrode 9, and the counter electrode 9 can be reduced.

Embodiment 5 FIG. In the first embodiment, the counter electrode 9 is configured only by stacking several slit plates 10. However, as shown in FIG. An electrically connected electrode stabilizer 13 may be attached. At this time, the electrode stabilizer 13 is provided with a plurality of gas supply holes 14 having an arbitrary shape that matches the sectional shape of the gas passage 12 of the slit 11 and is slightly larger than the sectional shape of the gas passage 12. As a result, gas can be supplied stably and plasma can be generated stably with good distribution.

Further, the shape of the gas supply hole 14 is arbitrary, but is circular as shown in FIG. 6A in the second embodiment, and is regular hexagon as shown in FIG. 6B in the third embodiment. By making the cross-sectional shape of the gas passage 12 of the slit 11 and the shape of the gas supply hole 14 match, the gas flow can be performed more smoothly.

Embodiment 6 FIG. Further, in the first and second embodiments,
3, 4, and 5, the cross-sectional shapes of the slit 11 of the slit plate 10 and the gas supply hole 14 of the electrode stabilizer 13 are rectangular, but as shown in FIGS. The cross-sectional shape of the supply hole 14 may be a trapezoid. In this case, as shown in FIG. 7C, the deposited film 8 mainly adheres to the slit 11 and the tapered portion 15 on the inner surface of the gas supply hole 14, so that the slit 11 and the gas supply hole 14 can be prevented from being blocked. Stable gas supply can be performed regardless of the amount of deposition of the deposited film 8.

Embodiment 7 FIG. Further, in the above embodiment, the CVD
Although the apparatus has been described, the present invention is not limited to this, and the same effects as those of the above embodiment can be obtained by any film forming apparatus such as a reactive sputtering apparatus that forms a film by introducing a reactive gas into the inside. .

[0026]

As described above, according to the present invention, the opposing electrode is constituted by a plurality of slit plates formed with a plurality of slits parallel to each other and arranged in parallel at a predetermined interval in the gas flow direction. Since the reactive gas is disposed between the slit and the slit plate by arranging the slit directions of the slit plate to be inclined with respect to each other, a stable gas supply can always be performed,
There is an effect that a stable film can be formed.

An electrode stabilizer electrically connected to the opposing electrode and disposed at a predetermined interval downstream of the gas is provided, and the electrode stabilizer has an area occupied by a slit of each slit plate. Since the gas supply hole is formed at a position corresponding to the portion overlapping in the direction of the gas flow, the gas flow can be further smoothly performed, stable discharge can be performed, and there is an effect that a stable film can be formed. .

[Brief description of the drawings]

FIG. 1 is a sectional view of a film forming chamber in a plasma CVD apparatus according to a first embodiment of the present invention.

FIG. 2 is a detailed explanatory view of a counter electrode shown in FIG.

FIG. 3 is a plan view showing a structure of a counter electrode according to a second embodiment of the present invention.

FIG. 4 is a plan view showing a structure of a counter electrode according to a third embodiment of the present invention.

FIG. 5 is a sectional view showing a structure of a counter electrode according to a fourth embodiment of the present invention.

FIG. 6 is a plan view showing a structure of an electrode stabilizer according to a fifth embodiment of the present invention.

FIG. 7 is a perspective view and a sectional view showing shapes of a slit and a gas supply hole of an electrode stabilizer according to a sixth embodiment of the present invention.

FIG. 8 is a sectional view of a film forming chamber in a conventional plasma CVD apparatus.

FIG. 9 is a diagram illustrating details of a conventional counter electrode.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Chamber 2 Wafer 3 Susceptor 9 Counter electrode 10 Slit plate 11 Slit 12 Gas penetration path 13 Electrode stabilizer 14 Gas supply hole

Claims (2)

(57) [Claims] A susceptor, which is one electrode on which a semiconductor substrate is mounted, and a counter electrode having a gas passage portion facing the susceptor in a chamber, wherein a reactive gas is passed through the gas passage portion of the counter electrode. In the film forming apparatus, a voltage is applied between the susceptor and the counter electrode to form a film on the semiconductor substrate. A plurality of slit plates arranged in parallel at a predetermined interval in the direction of, the reactive gas is arranged so that the directions of the slits of the adjacent slit plates are inclined with respect to each other, and the reactive gas is passed between the slit and the slit plate. A film forming apparatus characterized by passing through. 2. An electrode stabilizer, which is electrically connected to a counter electrode and is disposed downstream of the gas at a predetermined interval from the gas stabilizer, and wherein the electrode stabilizer has an area occupied by a slit of each slit plate. 2. The film forming apparatus according to claim 1, wherein a gas supply hole is formed at a position corresponding to a portion overlapping in a gas flow direction.