JPH079889B2 - Semiconductor wafer heat treatment equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a semiconductor wafer heat treatment apparatus for performing a predetermined heat treatment on a semiconductor wafer in a reaction tube.

(Prior Art) As an example of a peripheral technology of heat treatment such as oxidation, diffusion, and deposition in a semiconductor wafer process, satisfying the requirement of ultra-dust-free and atmosphere control in a loading system to a furnace body in a semiconductor wafer process Examples of technologies include USPAT. No. 4459104 and USPAT. No. 4543059.

Further, a rubber O-ring has been already used as a sealing material in the joint portion forming these reaction tubes.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional technique, when the treatment is performed at a relatively low temperature, good performance is obtained, but in the diffusion and the oxidation treatment performed in the high temperature, From the viewpoint of heat resistance, chemical resistance, etc., there is a risk of contamination in the reaction tube, so it was difficult to use the above-mentioned rubber O-ring.
Further, the conventional sealing material may generate dust due to thermal denaturation, which is not preferable in terms of cleanliness.

The present invention has been made in view of the above problems, and provides a semiconductor wafer heat treatment apparatus that does not undergo thermal denaturation even when a heat treatment reaction step is repeatedly performed and has improved contact contamination, and aims to solve the above problems. With the goal.

(Means for Solving the Problem) In order to achieve the above object, according to the present invention, in a heat treatment apparatus configured to perform a predetermined heat treatment on a semiconductor wafer in a reaction tube, a process tube forming the reaction tube and The process tube has a cantilever tube which can be inserted from the tip of the process tube from an opening end formed at one end of the process tube, and a gas supply port is provided at the other end of the process tube. A flange is formed at the open end, the tip of the cantilever tube is open, and a flange is formed in the vicinity of the rear end of the cantilever tube so as to be in close contact with the flange. At the rear end of the tube is a gas inlet that communicates with the inside of the cantilever. A holding table for arranging a plurality of semiconductor wafers, which are the objects to be processed, is provided therein, and further, on the joint surface between the flange portion and the flange,
There is provided a semiconductor wafer heat treatment apparatus characterized in that an O-ring made of glassy carbon is provided.

(Embodiment) An embodiment in which the device of the present invention is applied to an oxidation device and a diffusion device will be described in detail below with reference to the drawings.

A gas supply port (3) is provided at one end of a heat-resistant reaction tube, for example, a quartz process tube (2) arranged in the heat treatment furnace (1), and the gas supply port (3) is The gas supply system is connected to various reaction gas supply systems and purge gas supply systems necessary for the wafer process.

At the other end of the process tube (2), a flange portion (4) is formed on the outer circumference of the tip. The cantilever tube (5) is inserted from the flange portion (4) side, and the insertion operation in such a case is performed by the load station (6). The lower side of the load station (6) has a C-channel structure that supports a straight track on which a carriage is mounted.

The reaction gas is exhausted from the side of the scavenger (7) of the process tube (2) and the cantilever tube (5), which are reaction tubes, and is guided to an exclusion device (not shown).

A plurality of semiconductor wafers (8) are placed in a cantilever tube (5) having a gas inlet (9) on the opposite side of the furnace, and are made of a heat-resistant and highly clean material such as quartz. It is placed on a holding table (10).

The furnace side of the cantilever tube (5) is opened for inserting a holding table (10) containing a large number of standing semiconductor wafers (8) and for introducing gas into the semiconductor wafers (8). On the opposite side, two flanges (11) and (12) made of quartz, for example, are provided.

In the state of FIG. 1 (b) in which the cantilever tube (5) is inserted into the process tube (2) on the front flange (11) near the furnace side, the flange portion (4) of the process tube (2) and the front flange are O-ring made of glassy carbon (1) that hermetically seals the reaction vessel on the joint surface with (11)
3) is narrowly installed.

On the other rear flange (12), an O-ring (14) made of, for example, graphite is used so that it can be cantilevered on one end side of the cantilever tube (5). Since this part is outside the reaction vessel, normal graphite is used in this embodiment.

When a semiconductor wafer oxide film is formed using such an apparatus, in the state shown in FIG. 1 (a), for example, an inert gas such as a purge gas is supplied from each of the gas supply port (3) and the gas introduction port (9). The first in the state that the gas nitrogen gas is flowing
As shown in FIG. 2B, the cantilever tube (5) is inserted, mounted and then heated to a predetermined temperature by the heat treatment furnace (1).

Next, oxygen gas is introduced to create an oxygen atmosphere in each process tube (2) and cantilever tube (5). At this time, an inert gas such as nitrogen is used as the purge gas for the oxygen gas.

The semiconductor wafer (8) in a high temperature state, that is, silicon is very susceptible to contamination by metal alkaides and ions, which reduces the yield and life of the semiconductor.

Therefore, it is necessary to create a high-pressure atmosphere around the semiconductor wafer (8) to minimize particles from entering the cantilever tube (5) or adhering to the semiconductor wafer (8). Therefore, it is necessary to eliminate all the elements that generate dust.

In this embodiment, glassy carbon is used as a sealing material, specifically, an O-ring (13).
Then, slowly move the cantilever tube (5) until the O-ring (13) provided on the front flange (11) of the cantilever tube (5) faces the flange portion (4) of the process tube (2). The heat treatment reaction proceeds.

Next, the outline of glassy carbon will be described. Glassy carbon is produced by solid-phase thermal decomposition (carbonization) of organic substances, and includes what is called cellulose carbon, glassy carbon, hydrocarbon, and polymer carbon.
An example of the manufacturing method is as shown in FIG. The characteristics of glassy carbon are shown in the chart of FIG.

(Effect of the Invention) As described above, according to the semiconductor wafer heat treatment apparatus of the present invention, the O-ring made of glassy carbon is used at the joint surface between the flange portion of the process tube and the flange of the cantilever tube. Since there is no thermal denaturation even if the heat treatment reaction step is repeatedly performed and the sealing property of the joint is improved, the contamination of the process tube is suppressed and the heat treatment of the semiconductor wafer with a high rate by the reaction gas is performed. It is possible. Further, since contact damage is also prevented, even if the flange portion of the process tube and the flange of the cantilever tube are adhered to each other, the hermeticity is not impaired.

Moreover, since the gas supply port is provided at the other end of the process tube and the gas introduction port is provided at the rear end of the cantilever tube, when inserting the cantilever tube into the process tube, It is possible to perform such insertion operation while purging at the same time. Further, since a scavenger is provided near the outside of the above-mentioned joint surface, for example, an inert gas at the time of purging may diffuse into the reaction tube. It can be prevented.

[Brief description of drawings]

FIG. 1 is an explanatory view of an apparatus according to an embodiment of the present invention, FIG.
1 is an explanatory view showing a side surface and a cross section of an O-ring used in the embodiment of FIG. 1, FIG. 3 is a flow chart showing an example of a method for producing glassy carbon, and FIG. 4 shows characteristics of glassy carbon. It is a chart. In the figure, 1 is a heat treatment furnace, 2 is a process tube, 3 is a gas supply port, 4 is a flange portion, 5 is a cantilever tube, 7 is a scavenger, 8 is a semiconductor wafer, 9 is a gas introduction port, and 10 is a holder. 11 is a flange and 13 is an O-ring.

Claims (1)

[Claims] 1. A heat treatment apparatus configured to perform a predetermined heat treatment on a semiconductor wafer in a reaction tube, wherein a process tube constituting the reaction tube and an opening end formed at one end of the process tube are used for the process. There is a cantilever tube that can be inserted from the tip of the cantilever tube, a gas supply port is provided at the other end of the process tube, and a flange portion is formed at the opening end. Is formed, and a flange is formed near the rear end of the cantilever tube so as to be in close contact with the flange portion, and further, a gas introduction port communicating with the cantilever is provided at the rear end of the cantilever tube. In addition, a plurality of semiconductor wafers to be processed are arranged and held in the cantilever tube. A semiconductor wafer, wherein a base is provided, an O-ring made of glassy carbon is provided on a joint surface between the flange portion and the flange, and a scavenger is provided near the outside of the joint surface. Heat treatment equipment.