JPH07142392A - Semiconductor film forming device - Google Patents

Abstract

PURPOSE:To obtain uniform thickness of a film formed on a wafer, by changing a pair of a gas supply line and a gas exhaust line for supply and exhaust of a reacting gas with another pair of the gas supply line and the gas exhaust line. CONSTITUTION:The inside of a vacuum chamber 1 is kept under vacuum and the heating of the inside of the vacuum chamber 1 is stabilized by a heater 2. In the stabilized state, a secondary exhaust line valve 18, a secondary supply line valve 16, a slow exhaust line valve 12 and a secondary slow exhaust line valve 20 are closed, and a supply line valve 5 and an exhaust line valve 8 are opened, and a reacting gas is supplied from a gas supply line 4 and exhausted from a gas exhaust line 6. When a half of the wafer processing time is elapsed, the secondary exhaust line valve 18 is opened, the supply line valve 5 is closed, the secondary supply line valve 16 is opened and the exhaust line valve 8 is closed. As a result, the direction of the flow of the reacting gas is reversed during the forming of the film on the wafer 3 and uniform thickness of the film formed on the wafer 3 is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film forming apparatus which is one of semiconductor manufacturing apparatuses.

[0002]

2. Description of the Related Art A conventional semiconductor film forming apparatus will be described with reference to FIG.

A heater 2 is provided above and below a vacuum chamber 1 for accommodating a wafer 3, a gas supply line 4 is connected to the ceiling surface of the vacuum chamber 1, and the gas supply line is provided on the bottom surface of the vacuum chamber 1. A gas exhaust line 6 is communicated with the side opposite to the side with which 4 is communicated.

The gas supply line 4 is connected to a reaction gas supply source (not shown), and a supply line valve 5 is provided in the middle of the gas supply line 4. An exhaust pump 7 is provided at the downstream end of the gas exhaust line 6, and an exhaust line valve 8 and a conductance valve 9 are provided in the gas exhaust line 6 from the upstream side.

A slow exhaust line 11 is provided between the vacuum chamber 1, the exhaust line valve 8 and the conductance valve 9, and a slow exhaust line valve 12 and a needle valve are provided in the middle of the slow exhaust line 11 from the upstream side. 13 are provided.

A pressure detector 10 is installed in the gas exhaust line 6.
The pressure detected by the pressure detector 10 is input to the pressure controller 14, and the pressure controller 14 controls the opening by adjusting the opening of the conductance valve 9 based on the detected pressure.

When a wafer is set in the vacuum chamber 1 by a wafer transfer device (not shown), the vacuum chamber 1 is closed. The exhaust pump 7 is driven with the supply line valve 5, the exhaust line valve 8 and the slow exhaust line valve 12 closed. The slow exhaust line valve 12 is opened, the flow passage opening is adjusted by the needle valve 13, and the exhaust flow rate is adjusted while the vacuum chamber 1 is being adjusted.
Is exhausted slowly. When the inside of the vacuum chamber 1 is exhausted to a required pressure, for example, about 100 Pa to 200 Pa, the slow exhaust line valve 12 is closed and the exhaust line valve 8 is opened to perform main exhaust. The conductance valve 9 adjusts the exhaust flow rate in the main exhaust.

When the inside of the vacuum chamber 1 becomes a vacuum state of 0.5 Torr or less and the heating of the inside of the vacuum chamber 1 by the heater 2 becomes stable, the supply line valve 5 is opened and the reaction gas is supplied from the gas supply line 4. Supplied. The reaction gas has a high temperature in the vacuum chamber 1, and a reaction product is deposited on the surface of the wafer 3 by a chemical vapor deposition reaction to form a thin film. The gas after the reaction is the gas exhaust line 6
Then, the exhaust flow rate is controlled by the conductance valve 9, and the exhaust gas is exhausted by the exhaust pump 7.

When the thin film formation is completed, the exhaust line valve 8
Is closed, the inside of the vacuum chamber 1 is filled with an inert gas through an inert gas filling line (not shown), and when the inside of the vacuum chamber 1 is returned to atmospheric pressure, the vacuum chamber 1 is opened and a wafer transfer device (not shown) is used. Are unloaded.

[0010]

In the above conventional semiconductor film forming apparatus, the reaction gas introduced into the ceiling flows in one direction from one end side to the other end side of the bottom surface, and the film thickness of the thin film deposited on the wafer is There is a tendency that the reaction gas supply side becomes thicker and the exhaust side becomes thinner, and there is a problem from the viewpoint of uniform film quality and stable product quality.

In view of such circumstances, the present invention aims to provide a semiconductor film forming apparatus in which the film thickness formed on a wafer is uniform.

[0012]

According to the present invention, a plurality of pairs of gas supply lines and gas exhaust lines are provided in a vacuum chamber as a pair, and a gas flow generated by a pair of gas supply line and gas exhaust line and another pair. Of the gas supply line and the gas flow line generated by the gas exhaust line intersect with each other, and a plurality of pairs of the gas supply line and the gas exhaust line are provided in the vacuum chamber to form a pair. A pressure detector is provided in the line, a conductance valve is provided in each of the plurality of exhaust lines, and a pressure controller that performs the conductance valve opening control based on a signal from the pressure detector is provided, and a pair of gas supply lines are provided. The gas flow generated by the gas exhaust line and the gas flow generated by the other gas supply line and the gas exhaust line are configured to intersect with each other, and a plurality of gas pairs are formed. A line valve is provided in each of the supply line and the gas exhaust line, the gas flow can be selected by opening and closing the line valves in combination, and at least one conductance valve is PID-controlled, and at least one remaining is controlled to a fixed opening degree. It is characterized by the provision of a container.

[0013]

[Function] When the reaction gas is supplied, the gas flow is changed by changing the pair of gas supply line and gas exhaust line used for supplying and exhausting the reaction gas to another pair of gas supply line and gas exhaust line. In addition, the film thickness on the wafer is made uniform, and the pressure fluctuation caused by the opening and closing of the line valve when changing the gas flow, PID control for one of the conductance valves and fixed opening control for the other This suppresses pressure fluctuations.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

A first embodiment of the present invention will be described with reference to FIG.

In FIG. 1, the same components as those shown in FIG. 4 are designated by the same reference numerals.

A heater 2 is disposed above and below the vacuum chamber 1, a gas supply line 4 is connected to a ceiling surface of the vacuum chamber 1, and a side of the bottom surface of the vacuum chamber 1 is connected to the gas supply line 4. A gas exhaust line 6 is connected to the opposite side of the.

A reaction gas supply source (not shown) is connected to the gas supply line 4, and a supply line valve 5 is provided in the middle of the gas supply line 4.

The auxiliary gas supply line 1 is provided on the top surface of the vacuum chamber 1 at a position symmetrical to the communicating position of the gas supply line 4.
5, the auxiliary gas supply line 15 is provided with an auxiliary supply line valve 16, and the auxiliary gas exhaust line 17 is provided on the floor of the vacuum chamber 1 at a position symmetrical to the communicating position of the gas exhaust line 6.
And an auxiliary exhaust line valve 18 is provided in the auxiliary gas exhaust line 17.

The gas exhaust line 6 and the auxiliary gas exhaust line 17 are joined together, a conductance valve 9 is provided downstream of the joining position, and an exhaust pump 7 is connected to the conductance valve 9.

A slow exhaust line 11 is provided between the vacuum chamber 1, the exhaust line valve 8 and the conductance valve 9, and a slow exhaust line valve 12 and a needle valve 13 are provided in the middle of the slow exhaust line 11 from the upstream side. Is provided, and the vacuum chamber 1 and the position of the auxiliary gas exhaust line 17 downstream of the auxiliary exhaust line valve 18 are connected by an auxiliary slow exhaust line 19, and the auxiliary slow exhaust line 19 is connected to the auxiliary slow exhaust line valve from the upstream side. 20, auxiliary needle valve 21
Are provided in sequence.

A differential pressure detection line 22 is provided between the upstream side position of the exhaust line valve 8 and the upstream side position of the auxiliary exhaust line valve 18.
And a differential pressure detector 23 connected to the differential pressure detection line 22.
Is provided, and the signal from the differential pressure detector 23 is applied to the pressure controller 1
Enter in 4. The pressure controller 14 is the differential pressure detector 23.
The opening of the conductance valve 9 is adjusted by the signal from the.

The operation will be described below.

When the vacuum chamber 1 is evacuated after the wafer 3 is loaded, the supply line valve 5 and the auxiliary supply line valve 1
6, the exhaust line valve 8 and the auxiliary exhaust line valve 18 are closed, the slow exhaust line valve 12 and the auxiliary slow exhaust line valve 20 are opened, and the valve openings of the needle valve 13 and the auxiliary needle valve 21 are adjusted slowly. Then, the inside of the vacuum chamber 1 is brought into a vacuum state. For slow exhaust, only one of the slow exhaust line 11 and the auxiliary slow exhaust line 19 may be used.

When the pressure in the vacuum chamber 1 is reduced to the required pressure, the exhaust line valve 8 and the auxiliary exhaust line valve 18 are opened to exhaust.

When the inside of the vacuum chamber 1 becomes a vacuum state of 0.5 Torr or less and the heating of the inside of the vacuum chamber 1 by the heater 2 becomes stable, first, the auxiliary exhaust line valve 18, the auxiliary supply line valve 16 and the slow exhaust line are provided. The valve 12 and the auxiliary slow exhaust line valve 20 are closed, the supply line valve 5 and the exhaust line valve 8 are opened, and the reaction gas is introduced from the gas supply line 4 and exhausted from the gas exhaust line 6.

The reaction gas flows from the upper part to the lower part so as to traverse the vacuum chamber 1.

When half the processing time of the wafer 3 has elapsed, the auxiliary exhaust line valve 18 is opened, then the supply line valve 5 is immediately closed, the auxiliary supply line valve 16 is opened, and the exhaust line valve 8 is closed. In this state, the gas flow flows in the opposite direction to the first half of the wafer processing.

As described above, since the flow of the reaction gas changes in the opposite direction during the film formation on the wafer, the film thickness deposited on the wafer is made uniform.

In the above-described embodiment, two gas supply lines and two gas exhaust lines are provided so as to be switched during the film formation of the wafer. However, pressure fluctuation occurs when the valves are switched. Therefore, the pressure difference between the gas exhaust line 6 and the sub gas exhaust line 17 is detected by the differential pressure detector 23, and the exhaust flow rate of the exhaust pump 7 is adjusted by the pressure controller 14 to adjust the opening degree of the conductance valve 9. I am doing that.

Other embodiments including suppression of pressure fluctuation will be described below.

In the embodiment shown in FIG. 2, the gas supply line 25 is divided into the gas supply line 4 and the sub gas supply line 15, and the conductance valve 9 and the sub gas exhaust line 17 are connected to the gas exhaust line 6 and the sub gas exhaust line 17, respectively. An auxiliary conductance valve 26 is provided, and the conductance valve 9 and the auxiliary conductance valve 26 are connected to the differential pressure detector 23.
The pressure controller 14 adjusts the opening degree of the conductance valve 9 and the sub-conductance valve 26 in accordance with the detection result from (1) to control the pressure in the vacuum chamber 1.

The pressure control in this embodiment will be described.

Either the conductance valve 9 or the sub-conductance valve 26 is connected to the differential pressure detector 23.
The opening degree is controlled by the pressure controller 14 while monitoring the signal from, and the pressure control is performed by the PID control. Further, the other conductance valve is not subjected to PID control, but is a fixed opening degree control for gradually changing the valve opening degree from a predetermined opening degree. However, the relationship between the two conductance valves is not fixed and can be replaced as appropriate.

Further details will be described.

The conductance valve 9 in each steady state when the reaction gas is flowing from the gas supply line 4 toward the gas exhaust line 6 and from the sub gas supply line 15 toward the sub gas exhaust line 17, The opening degree of the sub-conductance valve 26 is obtained. That is, when the auxiliary supply line valve 16 and the auxiliary exhaust line valve 18 are closed and the reaction gas is flowing through the gas supply line 4 and the gas exhaust line 6, the opening degree of the conductance valve 9 is 45 with respect to the pressure value of 0.5 Torr. %, And when the supply line valve 5 and the exhaust line valve 6 are closed and the reaction gas is flowing through the auxiliary gas supply line 15 and the auxiliary gas exhaust line 17, the pressure value is 0.
The opening of the conductance valve 26 for 5 Torr is 42
The respective opening degrees of 45% and 42% when the percentage is set to% are stored in the memory.

Next, the flow direction of the gas from the gas supply line 4 to the gas exhaust line 6 at the set pressure value of 0.5 Torr is changed from the auxiliary gas supply line 15 to the auxiliary slow exhaust line 19.
Table 1 below shows the state of pressure control at the timing of switching to the flow direction to.

[0038]

[Table 1]

By performing the pressure control sequence as shown in Table 1 above, the pressure fluctuation in the reaction chamber can be minimized. Also, when the flow of the reaction gas is changed to the flow from the gas supply line 4 to the gas exhaust line 6, the pressure fluctuation can be suppressed in the same sequence.

In the embodiment shown in FIG. 3, each gas exhaust line 6,
The auxiliary gas exhaust line 17 is provided with an exhaust pump 7 and an auxiliary exhaust pump 27, respectively. When the inside of the vacuum chamber 1 is evacuated by the auxiliary exhaust pump 27, the ultimate vacuum is increased and the exhaust gas after the reaction is exhausted. Since the amount of inflow is also halved, the pump life is extended, the maintenance cycle is extended, the downtime of the apparatus is reduced, and the operation rate of the apparatus is improved.

In each of the above embodiments, two pairs of gas supply lines and gas exhaust lines are provided so that the gas flows face each other. However, three pairs or more are provided so that the gas flows radially intersect, and the gas flows are sequentially provided. It goes without saying that you can change it. Further, although each of the above-described embodiments shows the single-wafer type semiconductor film forming apparatus, it is needless to say that the present invention can be applied to a batch type semiconductor film forming apparatus for simultaneously processing a plurality of sheets.

[0042]

As described above, according to the present invention, the flow of the reaction gas during the wafer film formation process is changed, so that the film thickness is made uniform and the film quality is improved, and the flow of the reaction gas is changed. The excellent effect of suppressing pressure fluctuation due to opening and closing of the valve at the time is exhibited.

[Brief description of drawings]

FIG. 1 is a schematic view showing an embodiment of the present invention.

FIG. 2 is a schematic view showing another embodiment of the present invention.

FIG. 3 is a schematic view showing still another embodiment of the present invention.

FIG. 4 is a schematic view showing a conventional example.

[Explanation of symbols]

 1 Vacuum Chamber 4 Gas Supply Line 5 Supply Line Valve 6 Gas Exhaust Line 8 Exhaust Line Valve 9 Conductance Valve 15 Sub Gas Supply Line 16 Sub Supply Line Valve 17 Sub Gas Exhaust Line 18 Sub Exhaust Line Valve 26 Sub Conductance Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mamoru Sueyoshi 3-14-20 Higashi-Nakano, Nakano-ku, Tokyo Inside Kokusai Electric Co., Ltd.

Claims (4)

[Claims] 1. A plurality of pairs of gas supply lines and gas exhaust lines are provided in a vacuum chamber in pairs, and gas flows generated by one pair of gas supply lines and gas exhaust lines and other pairs of gas supply lines and gas exhaust lines. A semiconductor film forming apparatus, characterized in that it is configured so that the gas flow produced by 2. A pressure control, wherein a pressure detector is provided in an exhaust line, a conductance valve is provided at a downstream position where a plurality of exhaust lines are joined, and the conductance valve opening control is performed based on a signal from the pressure detector. The semiconductor film forming apparatus according to claim 1, further comprising a container. 3. A pressure detector is provided in the exhaust line, a conductance valve is provided in each of the plurality of exhaust lines, and a pressure controller for performing the conductance valve opening control based on a signal from the pressure detector is provided. Item 1. The semiconductor film forming apparatus according to item 1. 4. A vacuum chamber is provided with a plurality of pairs of gas supply lines and gas exhaust lines, pressure sensors are provided at the exhaust lines, and conductance valves are provided at the plurality of exhaust lines, respectively. And a gas flow generated by the pair of gas supply lines and the gas exhaust line, and a gas flow generated by the other pair of gas supply lines and the gas exhaust lines. Are configured to intersect with each other, line valves are provided for each of a plurality of pairs of gas supply lines and gas exhaust lines, the gas flow can be selected by opening and closing the combination of line valves, and at least one conductance valve is PID-controlled, and the rest A semiconductor film forming apparatus, characterized in that a controller for controlling a fixed opening degree of at least one of the above is provided.