JPS612327A - Conductance variable valve of semiconductor manufacturing device - Google Patents

Abstract

PURPOSE:To manufacture the titled valve with large variable ratio of conductance by a method wherein two rotary variable blades are fixed to be superposed while the space of opening formed by the variable blades is made almost proportional to the revolution of said variable blades. CONSTITUTION:Two rotary and variable blades 19 are fixed to the racks 21 in a valve case 20. The variable blades 19 are superposed by superposing parts 23. The space of opening 25 formed by the two variable blades 19 is made proportional to the revolution thereof. The racks 21 are respectively driven by independent driving devices engaged with the gears 22 of variable blades 19. Said space of opening 25 may be changed by shifting the racks 21 to keep the pressure in a reaction chamber 7 constant. Through these procedures, the pressure in reaction chamber 7 may be finely adjusted since the reaction of variable blades 19 and conductance may be made securely proportional to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a variable conductance valve for semiconductor manufacturing equipment.

[Background of the invention]

In semiconductor manufacturing equipment such as plasma etching equipment and plasma CVD equipment, a constant amount of reaction gas is introduced into a reaction chamber, and a variable conductance valve is provided between the reaction chamber and a vacuum pump to maintain the pressure inside the reaction chamber constant. As a result, a special gas atmosphere is created in the reaction chamber, and the sample is processed within the reaction chamber.

FIG. 2 is a schematic diagram showing a microwave discharge plasma etching apparatus. In the figure, 1 is a magnetron, 3 is a discharge region, 2 is a waveguide connecting the magnetron 1 and the discharge region 3, 4 is a solenoid coil provided around the waveguide 2, and 7 is connected to the discharge region 3 8 is a gas introduction valve installed in a conduit for supplying active reaction gas into the discharge region 3, 5 is a sample stage installed in the reaction chamber 7, and 9 is a gas introduction valve installed on the sample stage 5. The etching sample placed therein, 6 a permanent magnet attached under the sample stage 5, 13 a sample exchange chamber attached to the reaction chamber 7, and 12 a vacuum pump connected to the reaction chamber 7 via piping 24. , 10 is a gate valve provided in the pipe 24, and 11 is a variable conductance valve provided in the pipe 24.

In this plasma etching apparatus, a magnetic field is applied to the discharge region 3 by a solenoid coil 4 and a permanent magnet 6, and the discharge region 3 and reaction chamber 7 are controlled by a vacuum pump 12.
After evacuation is performed, a fixed amount of active reaction gas is introduced into the discharge region 3 through the gas introduction valve 8, and when microwaves generated by the magnetron 1 are supplied to the discharge region 3 through the waveguide 2, a discharge is caused. Starting, the etching sample 9 is subjected to plasma etching processing. And reaction chamber 7
The reaction product gas and residual reaction gas are exhausted by a vacuum pump 12 via a gate valve 10 and a variable conductance valve 11, but in this case, the pressure inside the reaction chamber 7 is maintained constant by the variable conductance valve 11.

FIG. 3 is a sectional view showing a conventional variable conductance valve, and FIG. 4 is a sectional view taken along line AA in FIG.

In the figure, 15 is a valve box, 14 is a valve seat fixed to the valve box 15, 14a is a hole provided in the valve seat 14, 17 is a drive device, 16 is a rod attached to the drive device 17, 18
is a valve fixed to the rod 16, and the valve 18 is slidably attached to the valve seat 14.

In this variable conductance valve, the drive device 1
By moving the valve 18 in the direction indicated by the arrow 7 via the rod 16, the opening area of the hole 14a can be changed and the pressure in the reaction chamber 7 can be kept constant. However, since leakage is likely to occur between the valve seat 14 and the valve 18, even if the opening area of the hole 14a is made small, the pressure inside the reaction chamber 7 will drop considerably. cannot be held at a high value, so
Since it is not possible to set a large conductance variable ratio, and a slight movement of the valve 18 causes a large change in conductance, and the amount of movement of the valve 18 is not proportional to the conductance, the pressure inside the reaction chamber 7 is finely adjusted. It is difficult to do so. Furthermore, if the length of the hole 14a increases, the stroke of the valve 18 must be increased, which increases the size of the drive device 17 and reduces its durability and reliability. Furthermore, even if the hole 14a is fully opened, the opening area of the hole 14a is
Since the cross-sectional area of the vacuum pump 12 is smaller than the cross-sectional area of , the evacuation capacity of the vacuum pump 12 cannot be maximized, and rapid evacuation cannot be performed.

[Purpose of the invention]

This invention was made in order to solve the above-mentioned problems. It is possible to have a large conductance variable ratio, it is easy to finely adjust the pressure inside the reaction chamber, and the durability and reliability of the drive device is improved. It is an object of the present invention to provide a variable conductance valve for semiconductor manufacturing equipment that is improved and capable of performing rapid exhaust.

[Summary of the invention]

In order to achieve this object, in the present invention, two variable blades are rotatably attached, and the two variable blades are provided with overlapping portions that are overlapped with each other. The area of the opening and the amount of rotation of the variable blade are made approximately proportional.

[Embodiments of the invention]

1 is a diagram showing a variable conductance valve of a semiconductor manufacturing apparatus according to the present invention, FIG. 5 is a sectional view taken along line BB in FIG. 1, and FIG. 6 is a sectional view taken along line CC in FIG. 1. In the figure,
20 is a valve box, 19 is two variable blades rotatably attached to the valve box 20, 23 is an overlapping part provided on each of the two variable blades 19, and the overlapping parts 23 are overlapped with each other. be done.

Reference numeral 25 denotes an opening formed by two variable blades, and the area of the opening 25, that is, the opening area is proportional to the amount of rotation of the variable blade 19. Reference numeral 21 denotes a rack movably attached to the valve box 20, and each rack 21 is driven by an independent drive device (not shown). 22 is a gear attached to the variable blade 19, and the gear 22 meshes with the rack 21.

In this variable conductance valve, the rack 21
By moving the variable blade 19, the opening area can be changed by rotating the variable blade 19, and the pressure inside the reaction chamber 7 can be kept constant. The overlapping portion 23 of the variable blade 19
are overlapped, and especially when the opening area is small, since the overlapping area of the overlapping portion 23 is large,
The amount of leakage is very small. Therefore, by reducing the opening area, it is possible to effectively suppress the pressure within the reaction chamber 7 from decreasing, and the pressure within the reaction chamber 7 can be maintained at a high value commensurate with the opening area. , the conductance variable ratio can be increased, the conductance will not change greatly due to a slight rotation of the variable blade 19, and the amount of rotation of the variable blade 19 and the conductance can be made reliably proportional, so that the reaction It is easy to finely adjust the pressure within the chamber 7. Furthermore, even if the opening area is increased, there is no need to increase the stroke of the rack 21, so the drive device can be made smaller and its durability and reliability are improved. Furthermore, since the opening area can be made approximately equal to the cross-sectional area of the pipe 24, the exhaust capacity of the vacuum pump 12 can be maximized.
Rapid evacuation is possible. Furthermore, variable wing 1
If 9 has a removable structure, the flow rate of the reaction product gas can be adjusted by attaching a variable blade having an arbitrary shape in place of variable blade 19, such as variable blades 26a and 26b as shown in FIG. , the pressure inside the reaction chamber 7, etc. can be set arbitrarily.

Furthermore, by fixing one variable blade 19 and rotating only the other variable blade 19, the pressure inside the reaction chamber 7 can be made even smaller than when two variable blades 19 are rotated at the same time. It can be changed.

FIG. 8 shows the pressure p in the reaction chamber 7 after a fixed amount of reaction product gas is introduced and the variable conductance valve 11 is completely opened. The opening degree of the conductance valve and the pressure p when it is fully opened when is set to 1.3X10-''Pa.

2 is a graph showing the relationship between the pressure P and the pressure ratio P/P o in the reaction chamber 7. Curve (a) shows the case where one variable vane 19 of the variable conductance vane valve according to the present invention shown in FIG. 1 is rotated, and then the other variable vane 19 is rotated, and curve (b) The case of the conventional variable conductance valve shown in FIG. 3 is shown. The maximum pressure in the reaction chamber 7 in both cases is the same. As is clear from this graph, in the conventional variable conductance valve, the pressure inside the reaction chamber 7 is approximately 1.3
In contrast, in the variable conductance valve according to the present invention, the pressure inside the reaction chamber 7 can be changed only within a range of 1.3 Pa.
It can be varied within a range of 3 Pa, and the variable conductance ratio of the variable conductance valve of the present invention is about 10 times that of the conventional variable conductance valve.

〔Effect of the invention〕

As explained above, in the variable conductance valve for semiconductor manufacturing equipment according to the present invention, the variable conductance ratio can be set to a large value, the pressure inside the reaction chamber can be easily finely adjusted, and the durability of the drive device can be improved. Because reliability is improved and rapid exhaust is possible,
Since the pressure inside the reaction chamber can be controlled reliably and accurately, it is possible to improve the performance of semiconductor manufacturing equipment. As described above, the effects of this invention are remarkable.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a variable conductance valve of a semiconductor manufacturing apparatus according to the present invention, FIG. 2 is a schematic diagram showing a plasma etching apparatus, and FIG. 3 is a sectional view showing a variable conductance valve of a conventional semiconductor manufacturing apparatus. Figure 4 is a cross-sectional view taken along line A-A in Figure 3, Figure 5 is a cross-sectional view taken along line B-B in Figure 1, Figure 6 is a cross-sectional view taken along line C-C in Figure 1, and Figure 7 shows other variable blades. FIG. 8 is a graph showing the relationship between the opening degree of the variable conductance valve and the pressure in the reaction chamber. 7.Reaction chamber

Claims (1)

[Claims] In a variable conductance valve of a semiconductor manufacturing apparatus, which is provided between a reaction chamber into which a quantitative amount of reaction gas is introduced and a vacuum pump, and is used to maintain a constant pressure in the reaction chamber,
A number of variable blades are rotatably attached, and the two variable blades are provided with overlapped portions that overlap each other, and the area of the opening formed by the two variable blades and the amount of rotation of the variable blade are A variable conductance valve for semiconductor manufacturing equipment characterized by almost proportional conductance.