JPH04320025A - Chemical vapor growth apparatus - Google Patents

Abstract

PURPOSE:To improve uniformity in the thickness of a thin film deposited over the top face of a semiconductor wafer by installing a doughnut-shaped plate of the same thickness as that of the semiconductor wafer in the periphery of the semiconductor wafer. CONSTITUTION:A doughnut-shaped ring plate 17 is formed to such a thickness as to be almost level with the surface of a semiconductor wafer 1 sucked on a wafer stage 3 when sucked by the ringlike plane 3a. The doughnut-shaped plate 17 is transferred into a reaction chamber by a transfer device and sucked by the doughnut-shaped plane 3a of the wafer stage 3. Successively, the semiconductor wafer 1 is sucked by the wafer stage 3. A reaction gas A is jetted at a constant flow speed from reaction gas jet openings 5 of a gas head 4. Therefore, the reaction gas A is decomposed in a near area of the semiconductor wafer 1 to deposit a thin film over the surface of the semiconductor wafer 1. The semiconductor wafer 1 is immediately taken out after a thin film is deposited, and the doughnut-shaped plate 17 is cleared of deposits on its top face and replaced by a new one before turning into waste.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] This invention provides a thermochemical reaction chamber with
A thin film is formed on the surface of the semiconductor wafer placed on the semiconductor wafer heating stage, which is placed opposite to the reaction gas injection holes, by ejecting the reaction gas from the multiple reaction gas injection holes provided in the gas head. The present invention relates to a chemical vapor deposition apparatus for forming.

0002

2. Description of the Related Art FIG. 3 is a sectional view of a main part of a reactor chamber shown in a chemical vapor deposition apparatus disclosed in Japanese Patent Application No. 1-106652. is fixed to a semiconductor wafer heating stage 3 (hereinafter simply referred to as wafer stage 3) heated by a heater 2 by vacuum suction.

The heater 2 is installed inside a wafer stage 3, and the wafer stage 3 is installed vertically facing a gas head 4. Gas head 4 has wafer stage 3
A large number of reactive gas ejection holes 5 are provided facing each other.

Reference numeral 6 denotes a thermochemical reaction chamber, and in the thermochemical reaction chamber 6, the reaction gas nozzle 5 of the gas head 4 is
The reaction gas A ejected at a more constant flow rate is decomposed in the vicinity of the semiconductor wafer 1, and a thin film is formed on the surface of the semiconductor wafer 1. An exhaust chamber 8 is installed above the side wall 7 of the thermochemical reaction chamber 6, and the exhaust chamber 8 is surrounded by an exhaust ring 9. Further, an exhaust port 10 communicating with the exhaust chamber 8 is provided on the side of the thermochemical reaction chamber 6, and an exhaust port 11 communicating with the gas processing chamber (not shown) is provided on the side of the exhaust chamber 8. , and an exhaust flange 12 is provided continuously on the outside of the exhaust port 11.

[0005] The exhaust gas B generated in the chemical reaction chamber 6 is introduced into the exhaust chamber 8 through the exhaust port 10, and then is introduced into the gas processing chamber (not shown) through the exhaust port 11 and the exhaust flange 12. It will be destroyed.

Reference numeral 13 indicates an exhaust resistance plate, and the exhaust port 11
This has the function of adjusting the pumping speed and rectifying the flow. Further, reference numeral 14 denotes a blowing ring, and the blowing ring 14 is provided with a blowing outlet 15 that opens toward the thermochemical reaction chamber 6 side.

A conventional chemical vapor deposition apparatus is constructed as described above, and a semiconductor wafer 1 is carried into a reaction chamber 6 by a transfer device (not shown), and is vacuum-adsorbed onto a wafer stage 3 heated by a heater 2. It is fixed by suction. on the other hand,
A mixed reaction gas A such as silane and oxygen is injected and supplied into the thermochemical reaction chamber 6 at a uniform flow rate from the reaction gas outlet 5 of the gas head 4. Then, the reaction gas A causes a thermochemical reaction to cause SiO2 on the surface of the semiconductor wafer 1.
Form a thin film such as

On the other hand, the exhaust gas B generated by the thermochemical reaction is led to the exhaust chamber 8 through the exhaust port 10, and further,
It is led through an exhaust port 11 and an exhaust flange 12 to a gas treatment device (not shown). In addition, N2 gas C passes through the air outlet 15 of the air outlet ring 14 into the stage gap 16.
The reaction product D is supplied into the thermochemical reaction chamber 6 to prevent the reaction product D from adhering to the side wall or the like.

[0009]

[Problems to be Solved by the Invention] In the conventional chemical vapor deposition apparatus as described above, the thin film formed on the surface of the semiconductor wafer is grown using N2 supplied from the peripheral part of the semiconductor wafer 1.
As shown in Figure 5, due to the influence of the flow of gas C, the film thickness at the periphery of the semiconductor wafer tends to be thicker than at the center, making it extremely difficult to make the film thickness uniform. .

[0010] This invention was made in order to solve the conventional problems, and eliminates the influence of N2 gas C supplied from the stage gap around the semiconductor wafer, and forms a uniform thin film on the semiconductor wafer surface. The purpose of the present invention is to provide a chemical vapor deposition apparatus that makes it possible to form.

[0011]

In the chemical vapor deposition apparatus according to the present invention, a donut-shaped plate having the same thickness as the semiconductor wafer is provided around the semiconductor wafer.

0012

[Operation] In the chemical vapor deposition apparatus configured as described above, of the thin film formed on the surface of the semiconductor wafer, the thicker part around the semiconductor wafer is formed on the donut-shaped plate. , the uniformity of the thickness of the thin film formed on the upper surface of the semiconductor wafer can be significantly improved.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional view of a reactor chamber showing an embodiment of the present invention, and FIG. 2 is a bottom view of a semiconductor wafer. In the figure, since numerals 1 to 16 and A to D are the same as those of the above-mentioned conventional device, the same numerals are given and the explanation thereof will be omitted.

Among these parts, the diameter of the wafer stage 3 is formed to be slightly larger than the diameter of the semiconductor wafer 1 which is suctioned and fixed to the surface of the wafer stage 3. Also, wafer stage 3
On the peripheral edge of the wafer stage 3, a ring-shaped surface 3a having a predetermined width and one step lower than the center is formed continuously in the circumferential direction of the wafer stage 3.

The semiconductor wafer 1 is vacuum-suctioned to the wafer stage 3, and the donut-shaped ring plate 17 is vacuum-suctioned to the ring-shaped surface 3a on the outer periphery of the semiconductor wafer 1. Note that the semiconductor wafer 1 and the donut-shaped plate 17 are fixed by being evacuated using different systems, so that they can be removed separately.

The donut-shaped ring plate 17 has a ring-shaped surface 3
It is formed to a thickness that is approximately flush with the surface height of the semiconductor wafer 1 that is adsorbed on the wafer stage 1 when it is adsorbed on the wafer stage 1, and it is also easy for deposits (mainly SiO2) to come into contact with the air. It is made of a material, such as quartz, whose coefficient of thermal expansion is approximately equal to that of the deposited material to prevent it from peeling off. Furthermore, in order to prevent deposits from adhering to the wafer stage 3, the donut-shaped plate 17 has a substantially L-shaped cross section so that the wafer stage 3 is not exposed in the gap between the donut-shaped plate 17 and the semiconductor wafer 1. It is formed.

In this configuration, the donut-shaped plate 17 is transported into the reaction chamber by a transport device (not shown) and is attracted to the donut-shaped surface 3a of the wafer stage 3. Subsequently, the semiconductor wafer 1 is attracted to the wafer stage 3 by a transfer device (not shown). Then, the reaction gas A is ejected from the reaction gas ejection port 5 of the gas head 4 at a constant flow rate. Therefore, the reaction gas A is decomposed in the vicinity of the semiconductor wafer 1, and a thin film is formed on the surface of the semiconductor wafer 1. Note that the semiconductor wafer 1 is taken out immediately after the thin film is formed.
The donut-shaped plate 17 is replaced with a new one before the deposits attached to its upper surface peel off and become trash.

FIG. 4 shows a donut-shaped plate 17 attached to a semiconductor wafer 1.
This figure shows the shape of a thin film formed on the surface of the semiconductor wafer 1 when it is provided in the peripheral area of the semiconductor wafer 1. Since the thick film thickness seen at the periphery of the semiconductor wafer 1 is formed on the donut-shaped plate 17, the semiconductor wafer 1 and the donut-shaped plate 17
Although there will be some unevenness due to the difference in level between the
It can be seen that a uniform thin film is formed on the surface of the semiconductor wafer 1.

In the above embodiment, a donut-shaped plate having a substantially L-shaped cross section was used, but a simple donut-shaped plate may be used.

[0020]

As explained above, according to the chemical vapor deposition apparatus of the present invention, since the donut-shaped plate having the same thickness as the semiconductor wafer is installed around the semiconductor wafer, the upper surface of the semiconductor wafer This has the effect that a thin film can be formed uniformly.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a reactor chamber of the invention.

FIG. 2 is a bottom view of the wafer stage in FIG. 1;

FIG. 3 is a sectional view of a main part of a conventional reactor chamber.

FIG. 4 is a cross-sectional view showing the shape of a thin film formed on the surface of a semiconductor wafer.

FIG. 5 is a cross-sectional view of a main part showing the shape of a thin film formed on the surface of a conventional semiconductor wafer.

[Explanation of symbols]

1 Semiconductor wafer, 3 Wafer stage (semiconductor wafer heating stage) 4 Gas head, 5 Reaction gas injection hole 6 Thermochemical reaction chamber 17 Donut-shaped plate

Claims (1)

[Claims] Claim 1: A reaction gas is ejected from a plurality of reaction gas ejection holes provided in a gas head in a thermochemical reaction chamber, thereby heating a semiconductor wafer on a semiconductor wafer heating stage provided opposite to the reaction gas ejection holes. A chemical vapor deposition apparatus for forming a thin film on the surface of a semiconductor wafer placed on a substrate, characterized in that a donut-shaped plate having the same thickness as the semiconductor wafer is installed around the semiconductor wafer. Vapor phase growth equipment.