JPH03249177A - Chemical vapor deposition system - Google Patents

Abstract

PURPOSE:To form uniform compd. thin films on the surfaces of substrates in a reaction chamber by providing slits of the shape resembling the sectional shape of a furnace tube on a partition wall forming member which segments the space in the furnace tube to the reaction chamber and a gas chamber and passing reactive gases from the slits. CONSTITUTION:The space in the furnace tube 32 provided in a heater 31 for heating is segmented to the reaction chamber 35 and the gas chamber 36 by the partition wall forming member 37. The semiconductor substrates 34 to be formed with films are disposed in this reaction chamber 35. The slit-shaped apertures 38 having the shape resembling the sectional shape of the furnace tube 32 or the substrate 34 are formed on the partition wall forming member 37 to communicate the two chambers 35, 36. Gaseous raw materials are introduced from a gas introducing pipe 43 into the gas chamber 36 of this chemical vapor deposition(CVD) system and are preheated; thereafter, the gases are supplied from the slits 38 into the reaction chamber 35. The gaseous raw materials are heated to a prescribed temp. by the heater 31 heating and are thereby brought into reaction, by which the compd. thin films are uniformly formed on the substrate 34 surfaces.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application J] The present invention relates to a CVD apparatus, particularly a low pressure CVD apparatus for forming a compound thin film on a semiconductor substrate.

[Prior art and its problems] A schematic diagram of a conventional low pressure CVD apparatus is shown in FIG.
), and a large number of semiconductor substrates (
A holder (3) holding a holder (4) is provided. In the figure of the reactor core tube (2), there is a reaction gas introduction tube (
5) from which a reaction gas is introduced into the inner space of the reactor core tube (2) via a valve (6). A gas outlet pipe (7) is provided on the other end wall.

Although the furnace core tube (2) and the holder (3) are schematically shown in FIG. 7, a part thereof is shown in more detail in FIG. The reactor core tube (2) consists of a tube body (8) mainly made of quartz, and the gas outlet end of this is equipped with an iron gas outlet tube (9).
is integrally fixed, and a connection port (9a) for connecting the outlet pipe (9) to the vacuum pump (see Fig. 7)
7) is formed. The quartz tube (8) is provided with the above-mentioned holder (3), which is provided with circular support members (3a) at both ends (only one end is shown), and between which a plurality of rods (3b) are provided. ) are connected to each other, and a number of aligned grooves (3c) are formed in this, and the peripheral edge of the disk-shaped semiconductor substrate (4) is inserted into this holder (3) and held therein. There is.

The conventional low pressure CVD apparatus is constructed as described above, and the semiconductor substrate (4) is heated to about 400 to 900°C by the heater (1) inside the furnace tube (2). On the other hand, the reaction gas introduced into the inner space of the furnace core tube (2) from the gas introduction tube (5) causes a chemical reaction such as thermal decomposition due to heat, and forms a compound thin film on the surface of the semiconductor substrate (4). The chemical reaction of the reaction gas depends on the supply amount of the gas, the reactor core tube (2)
and the pressure inside the reactor core tube (2).

As described above, a compound thin film is formed on the semiconductor substrate (4). The thickness is relatively thick, and in the inner space of the core tube (2) where the amount of reactant gas is relatively large, the reactant gas reacts in the gas phase and becomes powder. Figure 9 shows another conventional CVD apparatus, and this conventional example also has a vertical furnace core tube (fil) inside the heater fil.
12) is provided, and a holder (13) for supporting a large number of semiconductor substrates (14) is provided inside this.

The holder (13) is supported on a base (15) fixed to the bottom wall (12a) of the core tube (12), and the earthen wall of the core tube (12) is in a sealed state. This reactor core tube (12) has a concentric double structure.

That is, the outer core tube (12bl) and the inner core tube (12c)
), forming an annular passage (18) between them, and a gas introduction pipe (16) attached to the bottom wall (12a).
The reaction gas introduced from ) causes a reaction similar to that in the first conventional example, and is led out to the exhaust system through the passageway (18) as shown by the arrow. This conventional example also has the same drawbacks as the conventional example shown in FIG.

[Problems to be Solved by the Invention] The present invention has been made in view of the above-mentioned problems, and aims to provide a CVD apparatus capable of forming a uniform compound thin film on the surface of a semiconductor substrate disposed in a reactor core tube. purpose.

[Means for solving problems]

The purpose of the above is to
In the VD device, a partition forming member is provided that partitions the inner space of the reactor core tube into a reaction chamber and a gas chamber, and the partition forming member has a shape similar to the cross-sectional shape of the reactor core tube or is disposed in the reaction chamber, and a thin film is formed on the partition forming member. This is achieved by a CVD apparatus characterized in that a slit-like opening is formed that communicates the gas chamber and the reaction chamber, which have a similar shape to the substrate to be processed.

[For production]

The space within the reactor core tube is divided into a reaction chamber and a gas chamber, and the partition forming member for this partition has a similar cross-sectional shape to the reactor core tube for communicating the reaction chamber and the gas chamber, or is disposed in the reaction chamber. Since a slit-shaped opening is formed that has a similar shape to the substrate on which the thin film is to be formed, the reaction gas is introduced into the reaction chamber through this, thereby forming a compound thin film of varying thickness on the surface of the semiconductor substrate. can do.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reduced pressure CVD apparatus according to an embodiment of the present invention will be described below with reference to the drawings. 1 to 3 show the first embodiment. In the figures, a furnace core tube (32) similar to the conventional example is disposed inside the heater (31), but this inner space is filled with a partition wall forming member. (37), the reaction chamber (35) and the gas chamber (
36). The partition forming member (37) has a second
As shown in the figure, it is concentric with the cross section of the reactor core tube (32),
A circular slit (38) is formed that is concentric with and has the same diameter as the semiconductor substrate (34) (circular) on which the thin film is to be formed. A gas introduction pipe (43) is connected to the gas chamber (36) via a valve (39), through which a reaction gas is introduced into the gas chamber. In addition, as shown in FIG. 2, the partition forming member (37) has three circular slits.
8) is formed, for example, assuming that the partition forming member (37) is composed of a disk (37b) and an annular member (37a) as shown in FIG.
a) is directly fixed to the inner peripheral wall of the reactor core tube (32), while the disk (37b) is fixed to the inner peripheral wall of the reactor core tube (32) by a plurality of attachment members (41).
It may be fixed to the inner circumferential wall of 2). or,
Alternatively, the disk (37b) may be fixed to the right end wall (42a) of the reactor core tube (32) at its center via a connecting rod. Note that a gas outlet pipe (40) is connected to the left end wall (42b) as in the conventional case.

The CVD apparatus according to the first embodiment of the present invention is constructed as described above, and its operation will be explained next.

Before introducing the reaction gas into the gas chamber, the valve (39
), first close the reaction chamber (35) and the slit (
The gas chamber (36) communicates with the gas outlet pipe (38) through the gas outlet pipe (38).
The pressure is reduced to a predetermined pressure by a vacuum exhaust system connected to 40). After this, the valve (39) is opened and the reaction gas is supplied into the gas chamber (36) through the gas introduction pipe (43). The reaction gas diffuses into this gas chamber (36) and
is heated by the heater (31) and the slit (38
) into the reaction chamber (long).

The reaction gas is uniformly introduced into the reaction chamber (long) through the slit (38), which has the same diameter as the semiconductor substrate (34).
A compound thin film can be formed on the surface with a varying thickness. In addition, as in the past, introducing gas at a lopsided position in the reaction chamber produced powder due to the reaction in the gas phase, but such powder was not produced at all, and the above-mentioned effects did not occur. After performing this, the reaction gas is led out through the gas outlet pipe (40).

FIG. 4 shows a reduced pressure CVD apparatus according to a second embodiment of the present invention. This embodiment is of a so-called vertical type, and a vertical furnace core tube (70) is arranged inside a heater (51). This consists of an outer core tube (53) and an inner core tube (53).
2), forming an annular passageway (54) between them. Also, in the inner furnace tube (52), there is a holder (56) supporting a large number of semiconductor substrates (56) as in the first conventional example.
55) is arranged vertically and is fixed on a base (57). Furthermore, the bottom wall (58) of the inner core tube (52) is fixed at the same level as the bottom surface of the base (57), and the gas introduction pipe (72) is connected to this via the valve (71). ing. Inside the inner furnace tube (52) is a reaction chamber (73).
) and the gas chamber (74) are defined by a partition wall forming member (59), which is formed by an annular member (59a) and a small-diameter annular member concentric therewith ( 59
b), with an annular slit (60
) is formed. This diameter is a circular semiconductor substrate (56
) is the same as f. In addition, the inner annular member (59b)
is the base (57) of the holder (55) of the semiconductor substrate (56)
The slit (60) may be formed between this and the outer annular member (59a). Also,
The annular passageway (54) forms an annular gas outlet (54a) at the bottom of the furnace tube (70).

It is clear that the second embodiment also has the same effects as the first embodiment, so a detailed explanation thereof will be omitted.

As described above, according to the embodiments of the present invention, a thin compound film with a uniform thickness can be formed on the surface of a semiconductor substrate after a reactive gas is introduced into the reactor core tube. Furthermore, no powder is generated due to chemical reactions within the reactor core tube.

Although each embodiment of the present invention has been described above, the present invention is of course not limited to these (and various modifications can be made based on the technical idea of the present invention).

For example, in the above embodiment, the partition forming member (37) and (
Annular slits (38) (60) are formed in the semiconductor substrate (34) (59) on which a thin film is to be formed.
Although the outer diameter of the core tube (32) is set to be equal to the outer diameter of the core tube (56), it may be larger than this and slightly smaller than the inner diameter of the core tube (32) (52).

Furthermore, the slits do not have to be completely circular but may be polygonal.

Further, in the above embodiment, the annular slits (38) (60) were formed in the partition forming member, but instead of this, as shown in FIG. A small hole (80) may be formed. The slit-like opening according to the present invention has a large number of such small holes (80
) shall also be included.

Further, in the conventional example described above, the annular slit is formed by a concentric central disk or base (57) and an annular member around the outer circumference of the circular slit, but instead of this, two pipes are used. The pipe with a larger diameter may be fixed to the inner circumferential wall of the core tube, and the inner pipe with a smaller diameter concentric therewith may be fixed to a part of the core tube or an end wall of the core tube. The above-mentioned gas chambers (36) (74) may be formed between this inner pipe and the end wall of the core tube.

Furthermore, although a low pressure CVD apparatus was used in the above embodiments, the present invention is of course not limited to this and can be applied to general CVD apparatuses, such as normal pressure CVD apparatuses.

[Effects of the Invention] As described above, according to the CVD apparatus of the present invention, a compound thin film can be formed on the surface of a substrate on which a thin film is to be formed, with a much more uniform thickness than conventional methods.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a reduced pressure CVD apparatus according to a first embodiment of the present invention, FIG. 2 is a plan view of a partition wall forming member in the same embodiment, and FIG. 3 shows a part of the mounting force in FIG. 4 is a schematic sectional view of a reduced pressure CVD apparatus according to a second embodiment of the present invention, FIG. 5 is a plan view of a partition forming member in the same embodiment, and FIG. 6 is a schematic view of a partition forming member in the same embodiment. A plan view showing a modified example, FIG. 7 is a schematic cross-sectional view of a conventional low-pressure CVD apparatus, FIG. 8 is an enlarged cross-sectional view of a part of the conventional example, and FIG. 9 is another conventional low-pressure CVD apparatus. FIG. In the figure, 2) (70)... 41 (56)... 35) (73)... 36) ( 74)・・・・・・・・・ Furnace Core Tube Semiconductor Substrate Reaction Chamber Gas Chamber Partition Forming Member Slit 371 (59) (38) (60) Agent Yasuo Iisaka Figure 1 Figure 2 Figure 3: Reaction chamber 36 Gas chamber 37 Partition forming member 38 Fig. 4 0 Fig. 7 2... Furnace tube 4... Semiconductor device

Claims (1)

[Claims] In a CVD apparatus in which a furnace core tube is provided inside a heating heater, a partition forming member is provided that partitions the inner space of the furnace core tube into a reaction chamber and a gas chamber, and the partition forming member has a shape similar to or similar to the cross-sectional shape of the furnace core tube. A CVD apparatus characterized in that a slit-shaped opening is disposed in the reaction chamber and has a similar shape to a substrate on which a thin film is to be formed, and communicates the gas chamber and the reaction chamber.