JPH04196313A - Semiconductor manufacturing equipment - Google Patents

Abstract

PURPOSE:To prevent the blowing up of dust in a chamber and to contrive improvement in productivity by a method wherein the exhaust speed and the air-feeding speed in the chamber are decreased when the air exhaust and feeding operation are started, and the above-mentioned speeds are increased when the exhaust or feeding of air is going to be finished. CONSTITUTION:A controlling device 4 controls an exhaust system in such a manner that the exhaust speed S is reduced when pressure is high (at the starting of exhaust) based on the measured value of a pressure sensor 3, and the exhaust speed S is increased when the pressure is low (when exhaust operation is going to be finished). Under the above-mentioned condition, the pressure in a load lock chamber is always monitored by the pressure sensor, the absolute value of the pressure changing ratio in the load lock chamber is made small, and the blowing up of dust is prevented. As a result, the evacuation and feeding of air of the load lock chamber can be conducted in an efficient manner, and productivity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Applicability] The present invention relates to a semiconductor manufacturing apparatus having a load lock chamber on at least one of a wafer load side and a wafer unload side of a vacuum processing chamber.

[Conventional technology]

There is usually a
The load lock chamber is connected to prevent direct contact between the inside of the processing chamber and the outside air.

Here, Japanese Patent Laid-Open No. 60-238133 discusses whether it is possible to improve the productivity of semiconductor devices by evacuating the load lock chamber in a short time. A method has been proposed to solve the above problem by reducing the volume of the load lock chamber.

[Invention or problem to be solved]

However, if the volume of the load lock chamber is made small as in the conventional example above, the absolute value of the rate of pressure change will increase, especially at the start of exhaust and air supply, and the dust in the load lock chamber will be blown up and the semiconductor substrate There was a problem that dust could easily adhere to the surface.

On the other hand, as a method to solve this problem,
In Japanese Patent No. 128538, a semiconductor substrate to be processed is supported on a disk-shaped base, and this is pressed against a lid on the upper surface of a load-lock chamber, and the semiconductor substrate is housed in a recess formed in the lid and shielded from the load-lock chamber. However, depending on the method, the mechanical moving parts become a source of dust generation, and the above-mentioned problem cannot necessarily be solved. In addition, this method does not prevent dust from being stirred up; once dust is stirred up, it takes a long time for the dust to settle down again, resulting in a decrease in productivity. There were also points.

In order to avoid such dust being stirred up, if the exhaust and intake speeds are lowered, the time required for exhaust and intake becomes longer, which leads to a problem in that the production efficiency of semiconductor devices decreases.

Therefore, the present invention was made in consideration of these problems, and an object of the present invention is to prevent dust from being stirred up in the load lock chamber, and to efficiently exhaust and supply air to the load lock chamber. An object of the present invention is to provide a semiconductor manufacturing apparatus that can improve productivity.

[Means to solve the problem]

In order to solve the above problems by achieving the above object, the present invention includes a vacuum processing chamber and a load lock chamber installed on the wafer loading side or the wafer unloading side of the vacuum processing chamber. In a semiconductor manufacturing apparatus in which an exhaust device and an intake device are connected to each load lock chamber, a pressure sensor is provided that constantly monitors the pressure state within each load lock chamber, and based on the pressure detection value of this pressure sensor, Continuously control the exhaust or intake speed of the exhaust device or intake device so that the exhaust or intake speed is decreased at the start of exhaust or air supply, and increased as the exhaust or intake speed approaches the end of exhaust or air supply. and exhaust or intake speed control means.

[Effect]

The amount of dust kicked up by exhaust and air supply increases as the absolute value of the pressure change rate in the load lock chamber increases at the start of exhaust and air supply.The absolute value of the pressure change rate in the load lock chamber increases depending on the exhaust speed. , when the air supply speed is constant, it increases at the start of exhaust and air supply, and decreases as it approaches the end of exhaust and air supply.

Under these conditions, the present invention constantly monitors the load lock chamber pressure with a pressure sensor so that the exhaust or intake control device reduces the exhaust speed or air supply speed at the start of exhaust or air supply. , the absolute value of the pressure change rate in the load lock chamber is reduced, thereby preventing dust from being stirred up.

Moreover, at the end of exhaust or air supply, even if the pressure change rate in the load lock chamber is increased, the effect of dust kick-up is small. To improve exhaust or air supply efficiency by shortening air time.

〔Example〕

A first embodiment of the present invention will be described based on FIGS. 1 to 3. This embodiment shows an example in which the control device of the present invention is attached to an exhaust device of a load lock chamber.

FIG. 1 shows a configuration diagram around a load lock chamber of a semiconductor manufacturing apparatus. A vacuum pump 2 for evacuating the chamber IA is connected to a load lock chamber IA attached to the wafer load side of the vacuum processing chamber (not shown). Also, in the same room I
A is equipped with a pressure sensor 3 that constantly detects the pressure within the same chamber, and is further equipped with a control device 4 that controls the operation of the vacuum pump 2 based on information from the pressure sensor 3. Based on the measured value of the pressure sensor 3, this control device 4 reduces the pumping speed S when the pressure is high (at the start of pumping), and increases the pumping speed S when the pressure is low (at the end of pumping). The exhaust device 3 is controlled so as to. This control is performed by, for example, using a microcomputer to perform arithmetic processing that shows the pressure P-exhaust speed S characteristic as shown in FIG.

On the other hand, the pressure P in the load lock chamber IA and the time T required for evacuation are as follows.

P= (Po-Pa)exp(--t) 10 PaV However, S: Pumping speed (A/min: I■ = Internal volume of load lock chamber [A) Pl: Target pressure (torr) Pa: Attainment of pump Pressure (torr) PO: Normal pressure (torr) These results are shown in FIG. 3 as a pressure reduction characteristic diagram in the load lock chamber. The figure shows the ultimate pressure Pa of the vacuum pump 2, from normal pressure Po to low pressure P.

This shows the state where the pressure is reduced.

In method A of the present invention, the pumping speed S is reduced when the pressure P is high, and is increased as the pressure P decreases, so that the rate of pressure change at the start of pumping is small as α1, and the pumping speed S is increased when the pressure P is low. Sometimes it becomes as large as α2. Therefore, it can be seen that the pressure change rate exhibits an upwardly arched pressure reduction characteristic as shown by the solid line in the figure.

On the other hand, when we look at conventional method B, which performs pumping at a constant pumping speed S, as shown by the dotted line in the figure, the absolute value of the rate of pressure change at the start of pumping is as large as β1. Or, conversely, it becomes small to β2 at the end of exhaust, and as a result, it can be seen that the exhaust time T8 becomes long.

Therefore, depending on the method of the present invention, by controlling the pumping speed S, the absolute value 1 dP/cltl of the time change amount of the pressure P in the load lock chamber IA is made smaller at the start of pumping compared to the conventional method B. , and the exhaust time TA was changed to conventional method B.
It can be seen that the exhaust time T is set to be shorter than the exhaust time T.

A second embodiment of the present invention will be described with reference to FIGS. 4 to 6. In this embodiment, the control device of the present invention is attached to an air supply device of a load lock chamber.

FIG. 4 shows a configuration diagram around the load lock chamber of the semiconductor manufacturing apparatus, or a mass flow controller 5 is housed in place of the vacuum pump 2 of the first embodiment. And the control device of this embodiment! 4, based on the measured value of the pressure sensor 3, decreases the air supply speed R when the pressure is low (at the start of air supply), and increases the air supply speed R when the pressure is high (at the end of air supply). The air supply device 5 is controlled to do so.

As in the first embodiment, the pressure P-
This is done by the control device 4 performing arithmetic processing that indicates the air supply speed R characteristic.

Then, the pressure P, Th, and leak (air supply) time T in the load lock chamber IB can be determined as follows.

However, R: Supply air speed [β/m1n] -Pb: Back pressure of supply gas (back pressure of leak gas) (torr) P2: Pressure before leak (torr) In general, the back pressure of leak gas pb and The normal pressure Po is set equally.

FIG. 6 shows a pressure increase characteristic diagram in the load lock chamber in this state. This figure shows a state in which the pressure is increased from low pressure P2 to normal pressure Pc under the back pressure Pb of leak gas from the mass flow controller 5. However, in this case, the back pressure Pb of the leak gas and the normal pressure Po are assumed to be the same pressure.

Here, conventional method B, which supplies air at a constant air supply rate R, is shown as a comparative example, or depending on the conventional method B, the pressure increase characteristic as shown by the dotted line in the figure is shown, and the absolute value of the rate of pressure change is The slope becomes β3 with a steep slope at the beginning of air supply, and the slope becomes β4 with a gentle slope at the end of air supply.

On the other hand, the pressure increase characteristic of method A of the present invention exhibits a downwardly arched pressure increase characteristic as shown by the solid line in the same figure, and this pressure change rate is gradual as α3 at the start of air supply, and At the end of Qi, it shows a steep tendency like α4. Therefore,
Method A of the present invention can make the absolute value 16P/'dtl of the rate of pressure change in the load lock chamber IB smaller than the conventional method B at the start of air supply, and also allows the air supply time TA to be reduced from the conventional air supply time. It can be made shorter than T.

For other configurations and functions of this embodiment, please refer to Part 1.
Since this is the same as the embodiment, the explanation will be omitted.

As described above, depending on the semiconductor manufacturing apparatus of these embodiments, when exhausting and supplying air to the load lock chambers IA and IB,
The absolute value of the rate of pressure change at the start of exhaust and air supply can be made small. Therefore, in order to obtain the effect of preventing dust from being stirred up within the same room, it is possible to prevent quality deterioration of semiconductor substrates and the like to be processed.

Furthermore, by increasing the absolute value of the pressure change rate at the end of exhaust and air supply, efficient exhaust and air supply can be achieved, which reduces the exhaust and air supply times compared to conventional control methods. Productivity can be improved by making it shorter.

Note that the control of the exhaust and air supply speeds is not limited to those shown in these embodiments, and any control that increases the speed at the start of exhaust and air supply and decreases the speed at the end,
For example, the pressure change rate may be controlled to be constant, and the control may be determined by taking into consideration the shape and structure of the container.

〔Effect of the invention〕

Therefore, depending on the semiconductor manufacturing apparatus of the present invention, the indoor exhaust speed and air supply speed may be reduced at the start of exhaust or air supply, which have a large effect on the stirring up of dust, and the exhaust speed and air supply speed may be reduced. Alternatively, by increasing the size toward the end of the air supply, the exhaust and air supply of the load lock chamber can be efficiently performed, and the time for exhaust and air supply can be reduced, thereby improving the productivity of semiconductor devices. I can do it.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration around the load lock chamber of the semiconductor manufacturing equipment of the first embodiment, FIG. 2 is a graph showing pressure-pumping speed control characteristics, and FIG. 3 is a graph showing pressure reduction characteristics according to the same example. Fig. 4 is a diagram showing the configuration around the load lock chamber of the semiconductor manufacturing equipment of the second embodiment, Fig. 5 is a graph showing the pressure-air supply speed control characteristics, and Fig. 6 shows the pressure increase characteristics according to the same embodiment. It is a graph. IA, IB...Load lock chamber, 2...Vacuum pump, 3...Pressure sensor, 4...Control device, 5...Mass flow controller Patent applicant Kawasaki Steel Corporation

Claims (1)

[Claims] (1) It has a vacuum processing chamber and a load lock chamber installed on the wafer loading side or wafer unloading side of the vacuum processing chamber, and each load lock chamber is connected to an exhaust device and an intake device. In semiconductor manufacturing equipment,
A pressure sensor constantly monitors the pressure state in each of the load lock chambers, and based on the pressure detection value of this pressure sensor, the exhaust or air supply speed is reduced at the start of exhaust or air supply, and the exhaust or air supply approaches the end of exhaust or air supply. 1. A semiconductor manufacturing apparatus comprising: exhaust or intake speed control means for continuously controlling the exhaust or intake speed of the exhaust device or the intake device so that the exhaust or intake speed increases as the exhaust or intake speed increases.