JPS63239938A - Manufacturing apparatus for semiconductor device - Google Patents

Abstract

PURPOSE:To block the intrusion of outer air into a reaction furnace sufficiently when semiconductor substrates are carried into and out of the reaction furnace without a large amount of inactive gas, by specifying the gas jetting direction of each gas jetting port, which jets the inactive gas toward the semiconductor substrates that are carried into and out of a semiconductor substrate inputting port. CONSTITUTION:A reaction furnace 21, which heats semiconductor substrates 24, is provided in a semiconductor-device manufacturing apparatus. Jetting ports 31A, which jet inactive gas toward the semiconductor substrates 24 that are carried into and out of a semiconductor- substrate inputting port 23, are provided in the vicinity of the outer parts of the semiconductor- substrate inputting port 23 of the reaction furnace 21. The gas jetting direction of each gas jetting port 31A is set at an angle in the range of about 5-about 80 degrees toward the outside of the semiconductor-substrate inputting port 23, with the opening plane of the semiconductor-substrate inputting port 23 as a reference. For example, two or more shower nozzles 31 are attached to the outside of the semiconductor-substrate inputting port 23 of a vertical type pressure reduced CVD apparatus. The inactive gas is jetted to the semiconductor substrates 24, which are carried into and out of the reaction furnace 21 accompanied by the up and down movement of an elevator 28, through the above described gas jetting ports 31A.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a semiconductor device manufacturing apparatus equipped with a reaction furnace in which a semiconductor substrate is heated, such as a diffusion device or a CVD device. .

(Prior Art) In a semiconductor device manufacturing apparatus equipped with a reaction furnace in which a semiconductor substrate is heated, such as a diffusion device or a CVD device,
When carrying semiconductor substrates into and out of the reactor, outside air tends to enter the reactor through the semiconductor substrate loading port, causing a natural oxide film to form on the semiconductor substrates.

For example, in an element isolation process using selective oxidation, a silicon nitride layer 4 is formed as an oxidation mask on a polysilicon layer 3, as shown in FIG. 5(A). At this time, a natural oxide film 5 is formed on the polysilicon layer 3.

Next, by photophosphorography and dry etching,
The silicon nitride layer 4 is patterned and pre-processed for Fjcld oxidation, but at this time the native oxide film 5 on the polygon silicon layer 3 is etched down to the depths of the silicon nitride layer 4, as shown in FIG. 5(B). If field oxidation is performed in such a state, the effective width of the silicon nitride layer 4 as a mask becomes smaller, as shown in FIG. 5(C).
The pattern conversion difference ΔW between the field oxide film 6 and the silicon nitride layer 4 becomes abnormally large. This creates a high density circuit, which is disadvantageous.

FIG. 6 shows the thickness of the natural oxide film 5 and the pattern conversion difference ΔW.
This figure also shows that the natural oxide film 5
It can be seen that if the thickness is reduced, the pattern conversion difference ΔW is also reduced.

Furthermore, since the natural oxide film 5 acts as a barrier to diffused impurities during the diffusion process, it becomes difficult to control the amount of diffused impurities.

Therefore, in order to reduce the intrusion of outside air into the reactor, which causes the formation of such a natural oxide film, the semiconductor substrates being carried in and out of the semiconductor substrate micro-port are placed near the semiconductor substrate loading entrance of the reactor. There is already known a device that is provided with a gas injection port that injects an inert gas toward the container, and attempts to prevent the intrusion of the outer lid by υF by ejecting gas from the gas injection port.

FIG. 7 shows such a conventional device.

In the figure, a flat conductor J! of a reactor 8 surrounded by a heater 7! A shower nozzle 10 is provided near the periphery of the temporary loading port 9, and inert gas is injected from the gas injection port 10A toward the semiconductor substrate 12 being loaded into the reactor 8.

(Problem to be solved by the invention) However, in such a conventional device, the semiconductor substrate 12
When we investigated the relationship between the concentration of the inert gas (nitrogen) injected from the gas injection port 10A and the concentration of the outside air (oxygen) mixed in when the gas was brought in, we found that the oxygen concentration was It was found that in order to reduce this, it was necessary to increase the amount of nitrogen emitted.

In view of the above circumstances, the present invention sufficiently prevents outside air from entering the reactor when semiconductor substrates are carried into and out of the reactor, without requiring a polygonal inert gas.11. The purpose of the present invention is to provide a semiconductor device manufacturing apparatus that can perform the following steps.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the semiconductor device manufacturing apparatus according to the present invention has a
+ - A gas injection port is provided that injects inert gas toward semiconductor substrates being carried in and out from the conductor substrate loading port, and the gas injection direction of this gas injection port is It is characterized in that it is oriented at an angle within a range of about 5 degrees to about 80 degrees toward the outside of the semiconductor substrate loading port.

(Function) By setting the gas jetting direction of the gas jetting port to an angle within the range described in 1-1, it is possible to sufficiently prevent outside air from entering the reactor without jetting out multiple plates of inert gas. can do.

(Embodiment) FIG. 1 shows a vertical reduced pressure CVD apparatus according to an embodiment of the present invention.

The reactor 21 is composed of a vertically arranged quartz tube, and a flange portion 22 is disposed at the bottom of the reactor 21, and a semiconductor substrate loading port 23 is provided at the bottom of the flange portion 22. The semiconductor 1λ temporary 24 carried into and discharged from the semiconductor substrate loading port 23 into the reactor 21 is oriented horizontally one by one and with a predetermined interval between them.
Several sheets are stacked vertically and held in a quartz boat 25 in a removable manner. The quartz boat 25 is supported by a quartz boat support 26, and a flange portion 27 is attached to the quartz boat support 26. Additionally, the quartz boat support is attached to the elevator 28, and the quartz boat support is attached to the elevator 28.
can move vertically along the elevator support column 29.

At least two shower nozzles 31 are installed around the semiconductor substrate loading port 23, and from the gas injection port 31A of these shower nozzles 31, the elevator 28
Due to the vertical movement of the reactor 21 from the semiconductor substrate loading port 23,
Inert gas is injected toward the semiconductor substrate 24 being carried in and out. The gas injection direction of the gas injection port 31A is within a range of about 5 degrees to about 80 degrees toward the outside of the semiconductor substrate loading port (i.e., vertically downward) based on the opening surface of the semiconductor substrate loading port 23. It is oriented at an angle of .

Further, a heater 32 is provided around the reactor 21 so that the semiconductor substrate 24 inside the reactor 21 is heated.

Next, the operation of this embodiment will be explained.

When the quartz boat 25 in which the semiconductor substrate 24 is set is raised by the elevator 28 and carried into the reactor 21,
Inert gas is blown in the aforementioned direction from the shower nozzle 31 onto the semiconductor substrate 24 passing through the semiconductor substrate loading port 23 . As a result, the outside air remaining in the gaps between the semiconductor substrates 24 set in the quartz boat 25 is purged. Further, the inert gas from the shower nozzle 31 forms a gas curtain to prevent outside air from entering the reactor 21 due to entrainment from the gap between the quartz boat 25 and the semiconductor substrate loading port 23. Furthermore, a heater 32 is provided around the reactor 21 .

FIG. 2 shows the relationship between the gas jetting direction θ of the gas jetting port 31A and the oxygen 7a degrees inside the reactor 21. From this figure, when the gas injection direction of the gas injection port 31A is oriented at an angle within the range of about 5 degrees to about 80 degrees, the oxygen concentration in the reactor 21 is low, and especially at an angle of about 30 degrees to about 60 degrees.
It can be seen that the oxygen concentration decreases markedly when the angle is within the range of 100°.

According to this embodiment, it is possible to sufficiently prevent outside air from entering the reactor 21 when the semiconductor substrate 24 is carried into the reactor 21 without injecting a large amount of inert gas. Can be done.

Furthermore, when the semiconductor substrate 24 is carried out of the reactor 21 from the semiconductor substrate loading port 23, inert gas is ejected from the gas injection port 31A at the above-mentioned angle, so that the semiconductor substrate 24 is heated to a high temperature inside the reactor 21. After the semiconductor substrate 24 is taken out of the furnace, it can be covered with an inert gas for a certain period of time so that it does not come into contact with the outside air immediately. As a result, the formation of a natural oxide film outside the furnace is suppressed, and the cooling effect on the semiconductor substrate 24 can also reduce the oxidation rate. can be suppressed.

Further, since the semiconductor substrate 24 can be cooled, the next manufacturing process can be started quickly, and productivity is also improved.

Next, a horizontal furnace according to another embodiment of the present invention is shown in FIGS. 3 and 4.

The reactor 41 is composed of a quartz tube arranged horizontally, and a flange portion 42 is arranged at one end in the horizontal direction, and a semiconductor substrate loading port 43 is provided in the flange portion 42 . The semiconductor substrates 24 are each oriented vertically and are spaced apart from each other by a predetermined distance.
A plurality of sheets are arranged in a horizontal direction and are detachably held in a quartz boat 45. This quartz boat 45 is detachably held by a quartz fork 461- for taking in and out of the port.

A flange door 47 is attached to the flange portion 42 so as to be openable and closable, and at least two shower nozzles 48 are attached around the semiconductor substrate loading port 43. An inert gas is injected toward the semiconductor substrate 24 that is carried in and out of the reactor 41 from the semiconductor substrate loading port 43 on a quartz fork 46 for loading and unloading. The gas injection direction of the gas injection port 48A is approximately 5 degrees to approximately 80 degrees toward the outside of the semiconductor substrate loading port 43 (i.e., to the left side in the horizontal direction in the figure) with respect to the opening surface of the semiconductor substrate loading port 43. oriented at an angle within the range of

Even in the case of such a horizontal furnace, the same effects as in the case of the vertical furnace can be obtained.

Furthermore, the present invention is applicable not only to CVD apparatuses but also to other semiconductor device manufacturing apparatuses that include heat treatment such as a diffusion furnace.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to sufficiently prevent outside air from entering the reactor when carrying the semiconductor substrate into the reactor, without requiring a large amount of inert gas.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing a vertical reduced pressure CVD apparatus according to an embodiment of the present invention, and Fig. 2 shows the relationship between the angle of the gas injection port and the concentration of oxygen in the reactor in the same vertical reduced pressure CVD apparatus. Graphs, FIGS. 3 and 4 are cross-sectional views showing horizontal reactors according to other embodiments of the present invention, and FIG. 5 shows a process in which a natural oxide film formed by outside air mixed into the reactor becomes a field oxide film. 6 is a graph showing the relationship between the thickness of the native oxide film and the pattern conversion difference ΔW. FIG. 7 is a sectional view showing the conventional semiconductor device manufacturing apparatus.
FIG. 8 is a graph showing the relationship between the oxygen concentration in the reactor and the amount of nitrogen injected from the shower nozzle in a conventional apparatus. 21.41... Reactor, 22.42... Flange portion, 23.43... Semiconductor substrate loading port, 24... Semiconductor substrate, 25.45... Quartz boat, 27.47...
・Flange part, 31.48...Shower nozzle, 31
A. 48A...Gas injection port, 32.33...Heater. Applicant's agent Mr. Sato 65 Figure bμ'' Performance 4tqlrr;! Iin (mu) 6 wards milk 7 Figure X'! A ”* t-f (j/m1n)Kon8 Figure

Claims (1)

[Scope of Claims] 1. In a semiconductor device manufacturing apparatus equipped with a reaction furnace for heating semiconductor substrates, a semiconductor substrate that is carried in and out from the semiconductor substrate loading port is placed near the semiconductor substrate loading port of the reactor. A gas injection port is provided for injecting an inert gas toward the semiconductor substrate, and the gas injection direction of the gas injection port is directed toward the outside of the semiconductor substrate loading port with reference to the opening surface of the semiconductor substrate loading port. A semiconductor device manufacturing apparatus characterized in that the apparatus is oriented at an angle within a range of about 5 degrees to about 80 degrees. 2. The semiconductor device manufacturing apparatus according to claim 1, wherein the reactor is a vertical reactor having a semiconductor substrate loading port provided at the bottom.