JPS58116725A - Cvd apparatus - Google Patents

Abstract

PURPOSE:To realize growth of uniform film by arranging a holding means so that the main suface of wafer is faced downward and by locating a gas injecting means at the lower side of the holding means. CONSTITUTION:A susceptor 12 is closely fixed to a heater block 10 and wafers 14 are held by said susceptor with the main surfaces 18 faced downward by means of hooks 16. At the lower side of susceptor 12, a rail 50 is laid in the arranging direction of wafers 14 and a base 54 is put on the rail 50. At the upper part of base 54, a nozzle 56 is provided with the injection port 58 faced upward and a gas for growth of film is supplied through a pipe 60. In the case of this invention, gas is injected right upward to wafers and therefore a crystal powder formed in the vicinity of injection port of nozzle 56 drops downward and is hardly adhered to the main surface 18 of wafer 14.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides Cv[) (Chemical V ap
orQ epositon) apparatus, comprising a supporting means for supporting a semiconductor wafer for heating, and a gas ejecting means facing the supporting means and ejecting gas toward the main surface of the semiconductor wafer. The present invention relates to a CVD apparatus that forms a vapor phase growth layer on a surface.

Conventionally, in a CVD apparatus, a nozzle serving as a gas jetting means is provided above a susceptor serving as a supporting means. A semiconductor wafer, such as silicon, fixed to a susceptor is heated, and a vapor phase growth layer (Si 02 , P.S.G.
> is formed. Most of the gas ejected from the nozzle crystallizes and adheres to the mirror surface of the wafer, but some of the gas adheres to the vicinity of the nozzle outlet, forming crystalline powder there. Such powder not only adheres to the vicinity of the nozzle, but also often falls onto the wafer or susceptor below as the gas is ejected. The powder that falls onto the tube is trapped therein as the vapor phase growth layer grows.

The powder that falls onto the susceptor gradually accumulates and is scattered when the wafer is placed on the susceptor, and some of the powder is scattered on the wafer and incorporated into the vapor growth layer during the subsequent CVD process.

Powder taken into the vapor phase growth layer causes a thin layer around the layer or deteriorates the adhesion between the wafer and the growth layer. Also, when devices are later manufactured on a wafer, powder in the growth layer may fall off due to contact with the mask during mask alignment, creating holes in the growth layer.
The steep growth of the growth layer around the powder may cause poor adhesion to the resist, and stress may be applied perpendicularly to the mask from protruding powder areas, damaging the mask pattern or damaging the mask. There are many things.

Therefore, the present invention eliminates the drawbacks of the prior art and makes it possible to grow a uniform layer on the main surface of a semiconductor wafer without scattering crystalline powder and incorporating it into the vapor growth layer. The purpose is to provide a CVD device that can.

In the CVOI device according to the present invention, the supporting means is oriented so that the main surface of the semiconductor wafer faces downward, and the gas ejecting means is located below the supporting means, and the gas ejecting means is arranged from below toward the main surface of the semiconductor wafer. Gas is blown out.

Next, embodiments of the CVD apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram conceptually showing one embodiment of a CVOS device according to the present invention, in which a heater block 10 is shown.
A susceptor f12 is fixed in close contact with the susceptor 12, and the susceptor 12 can support a semiconductor wafer 14 such as silicon with the pins 16 or the like with its mirror surface 18 facing downward.

A rail 5o is installed below the susceptor 12 in the direction in which the wafers 14 are arranged, and a base 54 is movable by wheels 52.
is mounted on the rail 5o. A plurality of nozzles 56 are arranged on the upper part of the base 54 with jet ports 58 directed upward, that is, in a direction facing the susceptor 12 . A vibro 0 is connected to the end of the nozzle 56 opposite to the spout 58, which is connected to a cylinder (not shown) outside the base 54.
It is connected to the. As a result, gas containing a substance to be grown by CVD on the mirror surface 18 of the wafer 14, such as 02 and SiH4, is released from the spout 58 onto the wafer 14.
It is ejected towards the mirror surface of 4.

The base 54 can move on the rail 50 in the direction of arrow A. During this movement, the gas flows through the spout 5 of the nozzle 56.
8 and blows directly upward toward the wafer 14.

FIG. 2 shows another embodiment of the CVD @ device according to the present invention,
Elements similar to the embodiment of FIG. 1 are designated with the same reference numerals. In this example, the base 54 is fixed and the susceptor 1
2 and the heater block 10 can be moved in the direction of arrow A each time a wheel 24 mounted on an arm 22 runs on a rail 26.

3A and 3B are cross-sectional views showing another example of a method for mounting the wafer 14 on the susceptor 12. FIG. Susceptor 1
2A is provided with a recess 100 having a size and shape larger than the outer diameter of the wafer 14 at a location where the wafer 14 is mounted, and the wafer 14 is placed in this recess 100 and is held downward by the wafer support plate 102 as shown in FIG. 3A. Then, as shown in FIG. 3B, the support '1f1102 is fixed to the susceptor 12A by the locking member 104.

An opening 106 having a size and shape smaller than the outer diameter of the wafer 14 is provided in the support plate 102 in correspondence with the recess 100 .

Therefore, gas can be blown onto the main surface 18 of the wafer 14 from the nozzle 56 through this opening 106. In this structure, since the wafer 14 is in close contact with the susceptor 12A, the heat transmitted from the heater block 10 via the susceptor 12A is effectively conducted to the wafer 14.

In either embodiment, the heat generated by the heater 10 is transferred to the wafer 1 through the susceptor 12 or 12A.
4 and the temperature required for the CVD reaction is obtained at the surface 18 of the wafer 14. As the nozzle 56 gradually moves relative to the susceptor 12 or 12A, gas is ejected from the ejection port 58 of the lower nozzle 56 toward the susceptor 12 or 12A. The gas blown out from each nozzle 56 is appropriately mixed near the surface 18 of the wafer 14, and chemically reacts with the heat of the surface 18, so that a vapor phase growth layer such as silicon oxide Ill (Si 02 ) is formed on the wafer 14. Formed uniformly on the surface. In this way, the gas is ejected and distributed evenly over all the wafers 14,
A uniform oxide layer is grown on each wafer 14.

In the CVD apparatus according to the present invention, the crystalline powder formed near the spout of the nozzle 56 falls downward, so it is unlikely to adhere to the main surface 18 of the wafer 14. There is some possibility that some of this powder will be blown up and attached to the main surface 18 as the gas blows out, but that chance is very small, and even if it does, the main surface 18 will be facing downward. It is even less likely that it will remain on the surface for long. In addition, since the susceptor 12 or 12A itself faces downward, when the wafer 14 is stacked on the susceptor 12 or 12A, the crystalline powder is transferred to the susceptor 12 or 12A.
Even if it scatters from the wafer 12A, it rarely remains on the main surface 18 of the wafer 14.

Therefore, according to the present invention, a clean film free of crystalline powder can be grown on a semiconductor wafer. Note that gases with specific gravity heavier than air, such as 5iHi,
In the conventional method, where the main surface of the wafer faces upward and the gas is ejected from above to the bottom, there is a high possibility that such gas will remain near the main surface of the wafer. This adversely affects the uniform formation of the film. However, in the CVD apparatus according to the present invention, even in the case of a gas having a specific gravity slightly heavier than air, this gas does not remain in the vicinity of the main surface of the wafer after the nozzle passes, and the vapor phase growth is improved. Uniform formation is achieved.

[Brief explanation of drawings]

1 and 2 are conceptual diagrams showing an embodiment of a CVD apparatus according to the present invention. 3A and 3B are cross-sectional views showing other parts of the susceptor shown in FIG. 1 or 2 mIf. Explanation of symbols of main parts 10... Heater block 12... Susceptor 14... Semiconductor wafer 16... Pawl 26.5o...
Rail 24.52...Wheel 56...Nozzle 58...Spout port 102...Wafer support plate Applicant Pioneer Corporation Agent Patent attorney Motohiko Sunomura ! /Figure/θ

Claims (2)

[Claims] (1) A supporting means for supporting a semiconductor wafer for heating, and a gas ejecting means facing the supporting means and ejecting gas toward the main surface of the semiconductor wafer, In the CVD apparatus for forming a vapor-phase growth layer, the supporting means is disposed with the main surface of the semiconductor wafer facing downward, and the gas ejecting means is positioned below the supporting means so that the main surface of the semiconductor wafer faces downward. A CVD apparatus characterized in that the gas is ejected from below toward. (2) the supporting means supports a plurality of semiconductor wafers;
The CVDI training according to claim 1, wherein either one of the supporting means and the gas ejecting means is movable relative to the other along the arrangement direction of the plurality of semiconductor wafers. .