JPH02224237A - Vacuum treatment method - Google Patents

Abstract

PURPOSE:To prevent foreign matter from adhering to the substance to be treated by providing an exhaust pipe and a leakage pipe separately. CONSTITUTION:In the vacuum treatment method to treat the substance (wafer) 2 to be treated, which is stored in the chamber 3 after the inside of a chamber 3 is put in nearly vacuum conditions, and then to dissolve the vacuum state inside the chamber 3, the vacuum state inside the chamber 3 are dissolved using an introduction passage 9A for treatment gas to be filled in the chamber 3, different from a passage 5 for exhaust of chamber to put the inside of the chamber 3 in a nearly vacuum state. That is, an opening/closing valve 13 is installed in the middle of a gas introduction pipe 9a, and the gas introduction pipe 9A is also used as a leakage pipe to open it to the air (outside the chamber 3) by communicating with an air open pipe 15. Hereby, broken pieces adhering to an exhaust pipe, etc., are not scattered even by leakage action, and it can prevent the broken pieces from adhering to the substance to be treated such as a wafer 2, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a processing method such as plasma etching, vapor deposition, etc. carried out in the manufacturing process of a semiconductor device.

For example, plasma etching, which is performed as part of the manufacturing process of semiconductor devices, uses plasma (Freon plasma) to etch polysilicon or nitride films formed on the surface of a wafer. Alternatively, the process may be carried out in a substantially vacuum chamber filled with a small amount of CF, gas, or the like.

FIG. 1 shows a conventional apparatus for performing this plasma etching, in which a wafer 2, which is an object to be processed, is placed on a stage 1 that is moved up and down by a vertical movement mechanism (not shown).
When the wafer 2 is moved upward, the lower opening 3a of the chamber 3, which is formed in an inverted cup shape, is closed and the wafer 2 is set in the sealed space. A pair of concentric cylindrical electrodes 4, 4' for generating plasma are disposed within this chamber 3, and an exhaust pipe 5 for discharging air within the chamber to the outside of the chamber is opened for communication. This exhaust pipe 5 is connected to a vacuum pump 6, and a part thereof is connected to a leak pipe 8 having a three-way switching valve 7 interposed therein. 9 is a gas pipe through which processing gas flows into the chamber.

It is connected to a gas source 11 via a valve 1o.

Further, 12 is a seal ring.

Therefore, in this device, after the stage 1 was moved up to seal the inside of the chamber 3, the vacuum pump 6 was activated to make the inside of the chamber 3 into a vacuum state, and on the other hand, an appropriate gas was filled into the chamber 3 through the gas pipe 9. Later, a discharge is generated between the electrodes 4 and 4' to generate plasma, and the wafer 2 is etched. After the etching is completed, the on-off valve 7 is opened to leak air into the chamber 3, eliminating the vacuum state. This makes it possible to take out the wafer 2 (downward movement of the stage).

However, in processing methods using such conventional equipment, the same pipe line is used for exhaust gas and leakage inside the chamber, so wafer debris and post-etching products existing in the chamber are If the debris is sucked in with the air during exhaust and adheres to the inner wall of the exhaust pipe 5, the debris may be scattered into the chamber again by the leaked air flowing in the opposite direction along the inner wall during leakage. When such a phenomenon occurs, there is a risk that debris may adhere to the wafer and damage the wafer.

Such a problem may also occur in a vapor deposition apparatus having a similar apparatus configuration.

Therefore, an object of the present invention is to provide a vacuum processing method in which debris attached to an exhaust pipe or the like is not scattered into a chamber due to leakage, and in which debris can be prevented from adhering to objects to be processed such as wafers. It's about doing.

The gist of the present invention to achieve this object is to provide a vacuum processing method in which the inside of a chamber is brought into a substantially vacuum state, a workpiece stored in the chamber is processed, and then the vacuum state inside the chamber is eliminated. , characterized in that the vacuum state in the chamber is eliminated by using an introduction path for a processing gas to be filled into the chamber, which is separate from a path for exhausting the inside of the chamber to bring the inside of the chamber into a substantially vacuum state. It is in the vacuum processing method.

Hereinafter, the present invention will be described in detail based on the drawings.

FIG. 2 is a diagram showing a plasma etching apparatus used in carrying out the processing method of the present invention.

Reference numeral 1 denotes a stage that can be moved up and down by a vertical movement mechanism (not shown), and a wafer 2, which is an object to be processed (an object to be etched), is placed on its upper surface. Reference numeral 3 denotes an inverted cup-shaped chamber whose lower opening 3a is sealed to form a sealed space inside when the stage 1 moves upward, and is fixed to a support frame (not shown in Figure 1). A pair of concentric cylindrical electrodes 4, 4' for plasma generation is housed within this chamber 3. Further, an exhaust pipe 5 for discharging the air inside the chamber 3 to the outside of the chamber is opened and communicated with the upper bottom of the chamber 3, and is connected to a vacuum pump 6. On the other hand, near the bottom of the chamber 3 is a gas introduction pipe 9A for flowing a processing gas such as CF4 gas into the chamber.
The gas source 11 is connected to the gas source 11 through open communication. In this embodiment, an on-off valve 13 is interposed in the middle of the gas introduction pipe 9A, so that the gas introduction pipe 9A is communicated with the atmosphere release pipe 15 and is also used as a leak pipe for opening to the atmosphere (outside the chamber). It has become. 12 is a sealing member.

According to the above configuration, by moving the stage 1 upward, the lower opening 3a of the chamber 3 is sealed by the action of the sealing member 12, and a sealed space is formed within the chamber 3. Then, if the on-off valve 7A is opened and the vacuum pump 6 is activated,
The air inside the chamber is exhausted to the outside of the chamber 3 through the exhaust pipe 5, and the inside of the chamber 3 is brought into a vacuum or substantially vacuum state. In the case of plasma etching, usually 10-3 mmH
It should be around g.

In this state, or by operating the on-off valve 13, the gas introduction pipe 9
A is connected to the gas source 11, and when a voltage is applied between the electrodes 4 and 4' with some gas flowing into the chamber, plasma is generated and the polysilicon and nitride formed on the surface of the wafer 2 are generated. Etch the membrane.

After the etching is completed, the on-off valve 7A is opened.

10, operate the on-off valve 13, and then open the gas introduction pipe 9.
By communicating A with the atmosphere, air flows into the chamber 3 through the gas introduction pipe 9A, eliminating the vacuum state within the chamber. therefore.

This eliminates the pressure difference between the upper and lower surfaces of the stage 1, allowing the stage to move downward.

Now, looking at the movement of air in this embodiment, when air is discharged, air passes through the exhaust pipe 5, and therefore pieces of AHA adhere to the inner wall of the exhaust pipe, but when a leak occurs, the air passes through the exhaust pipe 5.
Since air flows into the chamber through A, air does not flow through the exhaust pipe in the event of a leak, thus preventing debris adhering to the inner wall of the exhaust pipe from scattering and adhering to wafers, etc., as in the conventional case. can do.

As a result, for example, during ion implantation in the next process, it is possible to prevent visitors from visiting the ion implantation site due to adhesion of foreign matter, thereby improving the manufacturing yield of semiconductor devices.

In addition, as a leak pipe, as shown by the imaginary line in Fig. 2,
The atmosphere opening pipe 15A having the on-off valve 14 interposed therein may be independently opened and communicated with the other side of the chamber 3.

In addition, as shown in FIG. 3, the present invention can be similarly implemented in a horizontal chamber apparatus.
Or equivalent parts are given the same reference numerals.

Furthermore, although the above embodiments are exemplified by an etching device,
The same method can be applied to other vacuum processing apparatuses such as vapor deposition apparatuses.

As described above, according to the present invention, since the exhaust pipe and the leak pipe are provided independently, it is possible to prevent foreign matter attached to the exhaust pipe during exhaust from being scattered during leakage, and to prevent foreign matter from entering the object to be processed. This has the effect of preventing adhesion and improving the manufacturing yield of semiconductor devices.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional device, FIG. 2 is a schematic perspective view of a device used in carrying out the present invention, and FIG. 3 is a cross-sectional view of a device used in another embodiment. 1... Stage, 2... Wafer, 3.
... Chamber, 4 ... Electrode, 5 ... Exhaust pipe, 6 ... Vacuum pump, 9, 9A gas introduction pipe, 11 ... Gas source, 13 ...・On-off valve,
14...Opening/closing valve, 15...Atmospheric release pipe, X...
・Fragments, etc. Figure 1, f Figure 3/Z Figure

Claims (1)

[Claims] 1. In a vacuum processing method in which the inside of the chamber is brought into a substantially vacuum state, a workpiece stored in the chamber is processed, and then the vacuum state inside the chamber is eliminated, in order to bring the inside of the chamber into a substantially vacuum state. A vacuum processing method characterized in that the vacuum state in the chamber is eliminated by using an introduction path for a processing gas to be filled into the chamber that is separate from a path for exhausting the inside of the chamber.