JPH04115531A - Chemical vapor growth device - Google Patents

Abstract

PURPOSE:To enable a reactive generated film with a uniform film thickness to be formed on a wafer by providing a throttle for restricting gas at a gas blow-off hole at a position corresponding to a central part of a semiconductor wafer. CONSTITUTION:A tubular pin 11 is formed in nearly cylindrical shape entirely and its outer diameter is formed to have dimensions for achieving engagement into a large aperture part of a gas blow-out hole 5. Also, this tubular pin 11 is fitted to a gas blow-out hole 5a at a central part of a gas head 4 out of a number of gas blow-out holes 5 which are provided at the gas head 4 and an inner diameter of the pin 11 is changed according to film-forming conditions. Flow of reaction gas which is supplied to a central part of the semiconductor wafer is suppressed by a throttle (tubular pin) and adjusted according to film- forming conditions, a reactive generated film with a uniform film thickness can be formed on a semiconductor wafer.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a chemical vapor deposition apparatus used in a film forming process for forming a reaction product film on a semiconductor wafer in the manufacturing process of semiconductor devices, and particularly relates to This relates to the structure of the supply gas head.

[Conventional technology]

Conventional chemical vapor deposition equipment of this type is shown in FIGS. 9 and 10.
It was configured as shown in the figure.

FIG. 9 is a sectional view showing a schematic configuration of a conventional chemical vapor deposition apparatus, and FIG. 10 is a plan view showing a gas head of the conventional chemical vapor deposition apparatus. In these figures, 1 is a semiconductor wafer (hereinafter simply referred to as a wafer), and 2 is a heating stage that holds this wafer 1. The stage 2 is configured to hold the wafer 1 on its lower surface, and its planar shape is approximately the same as that of the wafer 1. Reference numeral 3 denotes a heater for heating the stage 2 and the wafer 1 to a predetermined temperature, and this heater 3 is attached to the upper part of the stage 2.

Reference numeral 4 denotes a gas head for supplying the reactive gas A to the wafer 1, and this gas head 4 is provided with a large number of gas blowing holes 5 through which the reactive gas A is blown out.
It is arranged below the stage 2 at a distance B from the stage 2. Further, this gas head 4 is disposed on the same axis as the stage 2, and is positioned so that the center of the upper surface of the gas head 4 coincides with the center of the wafer holding surface of the stage 2. The gas blowing holes 5 are arranged in a range corresponding to the outer diameter of the wafer 1 held on the stage 2, and each gas blowing hole 5 is connected to a gas head 4 as shown in FIG.
There are openings arranged in a honeycomb pattern at equal intervals on the upper surface of the holder. Further, the gas blowing hole 5 is formed of a large diameter part that opens on the upper surface of the gas head 4, and a small diameter part that is formed in series below this large diameter part, and the dimensions of each part are determined by the film formation. It is formed with predetermined dimensions to suit the conditions.

6 is a reaction chamber wall that houses the gas head 4 and the like to form a reaction chamber, and 7 is an exhaust port. This exhaust lower is opened along the circumferential direction of the stage 20 at a position facing the side of the stage 2, and is configured so that the reaction gas A is exhausted to the outside of the reaction chamber through this exhaust lower. . Note that arrow C in the figure indicates exhaust.

In the conventional chemical vapor deposition apparatus configured as described above, a reaction is caused on the wafer 1 by supplying the reaction gas A blown out from the gas blowing hole 5 to the wafer 1 that has been preheated in the stage 2. A generated film can be formed.

[Problem to be solved by the invention]

However, in the conventional chemical vapor deposition apparatus, the exhaust port 6 is connected to the stage 2. Since it is located at the radially outer side of the gas head 4 and is provided over the entire circumferential direction, the gas blowing hole 5a provided at the center of the upper surface of the gas head 4 is located at all positions of the exhaust port 6. Since the position is the farthest away, the reaction gas A blown out from this gas blowing hole 5a is difficult to exhaust (and the time it spends floating along the surface of the wafer 1 is longer. The problem is that the reaction product film becomes thicker at the center of the wafer 1 facing the gas blowout hole 5a.

In FIGS. 9 and 10, reference numeral 5b indicates a gas blowing hole located radially outward of the gas head 4 from the gas blowing hole 5a among the many gas blowing holes 5. An example of this is shown in FIG.

FIG. 11 is a schematic diagram showing the film thickness distribution of a reaction product film when a conventional chemical vapor deposition apparatus is used.

As shown in the figure, if the film thickness at the part other than the center of wafer 1 is 10,000, the film thickness at the center of wafer 1 is 1
The number will increase to 4,000 people. The film forming conditions at this time were to use a chemical vapor deposition apparatus at normal pressure, and to use TE01 as the reaction gas A.
(tetraethoxysilane) gas, 03 (ozone) gas, and NZ (nitrogen) gas as a carrier gas.

The configuration of the device is as shown in FIGS. 9 and 10, the stage 2 has a diameter of 6mm, and the heater 3
It was heated to 00° C. and the gap B was set to 7B. The gas blowout hole 5 is formed in a range of φ6" including the center point on the upper surface of the gas head 4, and the large diameter part of φ4mm is
The small diameter part of φ1.5tm was set to 5wm. Further, the gas blowing holes 5 were arranged in a honeycomb shape, with the interval between the gas blowing holes 5 being 61 m, as shown in FIG.

With this device, the carrier N2 gas flow rate in reaction gas A was set to 20
jl! /wlin, and the film thickness distribution shown in FIG. 11 was obtained.

[Means to solve the problem]

In the chemical vapor deposition apparatus according to the present invention, a gas suppression aperture is inserted into each of the gas ejection holes at a position corresponding to the center of the semiconductor wafer, and this aperture is configured to control the flow rate of the reaction gas. The film is formed with dimensions that reduce the amount depending on the film forming conditions.

[For production]

The flow rate of the reaction gas supplied to the center of the semiconductor wafer is suppressed by the throttle and adjusted according to the film forming conditions.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in FIGS. 1 to 5 (a) to 5.
(f) will be explained in detail.

FIG. 1 is a perspective view showing a perforated pin of a chemical vapor deposition apparatus according to the present invention, FIG. Figure (a) ~
(f) is a schematic diagram showing the film thickness distribution on the wafer when using perforated bottles with different hole diameters, and (a) is a schematic diagram showing the film thickness distribution on the wafer when perforated bottles with different hole diameters are used.
．． 0 crane, the same figure (b) is 2°0 fl, the same figure (c) is 1.7
++n, the same figure (d) is 1.5 fl, the same figure (e) is 1.3
Crane, figure (f) is 1. The case of Otm is shown.

Figures 4(a) to 4(d) are schematic diagrams showing the film thickness distribution on the wafer when the gap between the stage and the gas head is changed without changing the perforated bottle. The figure (b) shows 4 cranes, the figure (b) shows 7++++s, the figure (c) shows 10 fins, and the figure (
d) shows the case of 13 cranes. FIGS. 5(a) to 5(f) are schematic diagrams showing the film thickness distribution on the wafer when only the flow rate of the carrier gas is changed, and FIG. 5(a) is a diagram showing the film thickness distribution on the wafer when only the flow rate of the carrier gas is changed. The flow rate is 201! /win, figure (b) is 17.51! /
min, the same figure (c) is 1517 m1n, the same figure (d) is 1
2.51/min.

The figure (e) is 101/ll1in, the figure (f) is 7.5
The case of #/l1lin is shown. In these figures, the same or equivalent members as those explained in FIGS. 9 and 10 are given the same reference numerals and detailed explanations will be omitted. In these figures, reference numeral 11 denotes a perforated bottle serving as a diaphragm, and the perforated bottle 11 is formed into a generally cylindrical shape as a whole, and its outer diameter is such that it can be fitted into the large diameter portion of the gas blowing hole 5. It is formed with. Further, as shown in FIG. 2, this perforated bottle 11 is attached to a gas blowing hole 5a in the center of the gas head 4 among the many gas blowing holes 5 provided in the gas head 4. In addition, the length dimension of this perforated bottle 11 is 5 cranes in this embodiment,
The inner diameter is changed depending on the film forming conditions. FIGS. 3(a) to 3(f) show an example in which a reaction product film is formed on the wafer 1 by changing the inner diameter with the length dimension being five cranes.

In Figs. 3(a) to (f), a perforated bottle 11 with a length 51 and a different inner diameter is used, and a reaction product film with a thickness of 100 mm is formed on the wafer l under the same film forming conditions as before. FIG. 3 is a schematic diagram showing a film thickness distribution when the film is generated.

According to FIGS. 3(a) to (f), when the inner diameter is 3.0 mm, there are 13,500 people at the center of the wafer 1, when the inner diameter is 2.0 mm, there are 12,000 people, and when the inner diameter is 1.0 mm, there are 12,000 people at the center of the wafer 1. 1 for 7H
0000 people, 9100 people if the inner diameter is 1.5 fl,
When the inner diameter is 1.3 fins, there are 8,500 people, and when the inner diameter is 1.0 fins, there are 8,000 people, compared to the case where the perforated bottle 11 is not used under the same film forming conditions as shown in FIG. As the diameter of the hole is reduced by the perforated bottle 11, the film thickness at the center of the wafer 1 gradually decreases, and the film thickness at the center becomes thinner than at the periphery. Under the film forming conditions in this case, as shown in FIG.
When a perforated bottle 11 with an inner diameter of 1.7 gm and a length of 5 fl is used for a, a uniform film thickness distribution can be obtained.

In addition, FIGS. 4(a) to 4(d) show that a perforated bottle 11 with an inner diameter of 1.5 fl and a length of 5H is attached to the central gas blowing hole 5a under the above-mentioned film forming conditions, and the stage 2 and the gas head 4 are connected to each other. FIG. 3 is a schematic diagram showing the film thickness distribution when the gap B between the two layers is changed. According to FIGS. 4(a) to (d), the gap B is 4n
In the case of , the film thickness at the center of the wafer 1 is 8000, when the gap B is 7, it is 9100, and the gear B is Ion.
If gap B is 131'm, there will be 9,500 people, and if gap B is 131'm, there will be 9,800 people. In this way, the film thickness distribution at the center of the wafer 1 changes depending on the gap B, so by using the perforated vials 11 having different inner diameters depending on the degree of the gap B, a uniform film thickness distribution can be obtained.

Further, FIGS. 5(a) to 5(f) show that under the above-mentioned film forming conditions, a perforated bottle 11 with an inner diameter of 1.5+n and a length of 5n is attached to the central gas blowing hole 5a, and the carrier N2 gas in the reaction gas A is FIG. 3 is a schematic diagram showing the film thickness distribution when the flow rate of is changed. According to FIGS. 5(a) to (f), when the carrier N2 gas flow rate is 2012/+in, the film thickness at the center of the wafer 1 is 9100 mm, and when the carrier N2 gas flow rate is 17.51/min, it is 920 mm thick.
0 people, 930o people in case of 151/1lin, 12.
5 j! /min, 9400 people, 1017m1
nO) case 9,600 people, 7.51/win case 9
There will be 800 people. In this way, the film thickness distribution at the center of the wafer 1 changes depending on the flow rate of the carrier N2 gas, so by using the perforated bottle 11 with a different inner diameter depending on the flow rate of the carrier N2 gas, a uniform film thickness distribution can be achieved. can get.

Therefore, as described above, by changing the inner diameter of the perforated bottle 11 according to the film-forming conditions, the flow rate of the reaction gas A supplied to the center of the wafer 1 is suppressed by the perforated bottle 11, and the film-forming conditions It will be adjusted accordingly.

In order to suppress the flow rate of the reaction gas A using the perforated bottle 11, in addition to changing the inner diameter as described above, it is also possible to change the length dimension as shown in FIGS. 6 and 7.

Figures 6 and 7 are diagrams showing other embodiments in which the length of the hole pin is changed, and Figure 6 is similar to Figures 1 to 5 (a).
A cross-sectional view showing a state in which a hole pin having twice the length of the hole pin used in the examples shown in (f) is attached to the gas head, and Figure 7 shows the gas head shown in Figure 6. FIG. 2 is a schematic diagram showing a film thickness distribution on a wafer when a film is formed using a head.

In these figures, the same or equivalent members as those explained in FIGS. 1 and 2 are given the same reference numerals, and detailed explanations will be omitted. The hole pin 11 used in this example has an inner diameter of 2.0 wm and a length of 10 m, and is similar to the hole pin 11 used in the examples shown in FIGS. 1 to 5 (a) to (f). It is said to be twice the length. When a reaction product film is formed on a wafer 1 using a hole pin 11 having twice the length as described above under the same film forming conditions as in the above embodiment, as shown in FIG. The film thickness was 10,800 people. According to FIG. 7, the above-mentioned FIG. 3 (
It can be seen that the film thickness is thinner at the center of the wafer 1 compared to the case where the wide open pin 11 with an inner diameter of 2.0 mm and a length of 5 mm as shown in b) is used. That is, the thickness of the reaction product film formed at the center of the wafer 1 can be changed not only by changing the inner diameter of the hole pin 11 but also by changing its length.

In addition, if the film thickness at the center of the wafer 1 varies over a wide range depending on the film forming conditions, multiple types of hole pins 11 with different lengths, inner diameters, etc. may be attached to the gas head 4 as shown in FIG. It can also be attached to the center of the

FIG. 8 is a sectional view showing another embodiment in which a plurality of hole pins of different lengths are attached to the gas head, and this figure is the same or equivalent to the one explained in FIGS. 1 to 7 above. The same reference numerals are given to the members, and detailed description thereof will be omitted. In FIG. 8, hole pins 11 having different sizes are attached to a gas blowing hole 5a located at the center of the upper surface of the gas head 4 and a gas blowing hole 5b adjacent to the gas blowing hole 5a. Even in this manner, a uniform film thickness distribution can be obtained.

It goes without saying that the shape and dimensions of each part of the film-forming reaction chamber and the type of reaction gas A used in each of the above embodiments are not limited to those described above.

〔Effect of the invention〕

As explained above, the chemical vapor deposition apparatus according to the present invention,
A gas suppression restrictor is inserted into each gas blowout hole at a position corresponding to the center of the semiconductor wafer, and this restrictor is formed with dimensions to reduce the flow rate of the reaction gas depending on the film forming conditions. Therefore, the flow rate of the reaction gas supplied to the center of the semiconductor wafer is suppressed by the throttle and adjusted according to the film forming conditions. Therefore, a reaction product film having a uniform thickness can be formed on the semiconductor wafer.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a perforated pin of a chemical vapor deposition apparatus according to the present invention, FIG. Figure (a) ~
(f) is a schematic diagram showing the film thickness distribution on the wafer when hole pins with different hole diameters are used, and (a) is a schematic diagram showing the film thickness distribution on the wafer when hole pins with different hole diameters are used.
．． 0fi, the same figure (b) is 2°0 crane, the same figure (c) is 1.7
m, Figure (d) shows the case of 1.5 dragon, Figure (e) shows the case of 1.3 crane, Figure (f) shows the case of 1.0 crane. Figures 4(a) to 4(d) are schematic diagrams showing the film thickness distribution on the wafer when the distance between the stage and the gas head is changed without changing the hole pin, and Figure 4(a) is a diagram showing the film thickness distribution on the wafer when the gap between the stage and the gas head is changed without changing the hole pin. is 4fi,
The same figure (b) is 7 cranes, the same figure (c) is 10mm, the same figure (d)
shows the case of 13m. Figures 5(a) to 5(f) are schematic diagrams showing the film thickness distribution on the wafer when only the flow rate of the carrier gas is changed. Figure (b) is 17.51/va
tn-b (C) is 151/1ain, (d)
is 12.5 A'/akin, and (e) is 10 I
t/+in, Fig. 6(f) shows the case of 7.517+nin, Figs. 6 and 7 show other embodiments in which the length of the hole pin is changed, and Fig. 6 shows the case of 7.517+nin. Figures 1 to 5
Figure 7 is a cross-sectional view showing the state in which a hole pin with twice the length of the hole pin used in the embodiment shown in Figures (a) to Cf'' is attached to the gas head. Fig. 8 is a schematic diagram showing the film thickness distribution on a wafer when film formation is performed using the gas head shown in Figure 8. FIG. 9 is a sectional view showing a schematic configuration of a conventional chemical vapor deposition apparatus, FIG. 10 is a plan view showing a gas head of a conventional chemical vapor deposition apparatus, and FIG. The figure is a schematic diagram showing the film thickness distribution of a reaction product film when a conventional chemical vapor deposition apparatus is used. 4... Gas head, 5.5a, 5b... Gas blowing hole, 1... Hole pin.

Claims (1)

[Claims] A gas blowing hole for blowing reactive gas onto the semiconductor wafer has a large number of gas heads provided at a portion facing the main surface of the semiconductor wafer, and the reactive gas sprayed onto the semiconductor wafer is exhausted to the side of the semiconductor wafer. In the chemical vapor deposition apparatus, a gas suppression throttle is inserted into the gas outlet hole at a position corresponding to the center of the semiconductor wafer among the gas outlet holes, and this throttle controls the flow rate of the reaction gas. A chemical vapor deposition apparatus characterized in that it is formed with dimensions that are reduced depending on film conditions.