JP2542695B2 - Plasma etching equipment - Google Patents

Description

The present invention relates to a plasma etching apparatus, and more particularly to a plasma etching apparatus having a mass flow controller for controlling the flow rate of an etching gas.

[Conventional technology]

Conventionally, in this type of plasma etching apparatus,
When checking the flow rate of a mass flow controller (hereinafter referred to as MFC) that controls the etching gas (hereinafter referred to as process gas), select 1 of the target process gas piping.
Remove the part, connect the calibration flow meter to that part, flow an inert gas for calibration in the order of MFC from the flow meter for calibration, and compare the flow rate display of the MFC and the flow meter for calibration at this time. I was checking the flow rate. This will be described below with reference to the schematic diagram of FIG.

When checking the flow rate of MFC Remove the pipe from the out side of the gas valve 1b on the target process gas pipe, connect the calibration flow meter to the out side of the gas valve 1b, and make it inert from the upstream side of the process gas pipe for calibration. Let the gas flow. In this state, the MFC flow controller 6 sends a signal of an arbitrary flow rate value to the MFC 2A, and the actual flow rate check is performed by comparing the flow rate value when the set flow rate is flown with the flow rate value of the calibration flow meter.

[Problems to be Solved by the Invention]

In the conventional plasma etching apparatus described above, the gas valve has to be removed and the calibration flow meter has to be connected when the flow rate is checked. For this reason, it is difficult to check the actual flow rate of the MFC, which makes it difficult to detect problems such as clogging of the MFC piping and malfunctions at an early stage.

In contrast to the above-described conventional plasma etching apparatus, the present invention is equipped with a gas line equipped with a mass flow meter (hereinafter referred to as MFM) for checking the actual flow rate of MFC, so that an inert gas for checking is flowed to the MFC. Compared with the MFM flow rate display, the actual flow rate check can be easily performed.

[Means for solving the problem]

A plasma etching apparatus of the present invention has a processing chamber for holding a semiconductor substrate and performing an etching process, a gas pipe for supplying an etching gas to the processing chamber, and a mass flow controller provided in the gas pipe. In the plasma etching apparatus, a check pipe for flowing an inert gas for checking the actual flow rate is provided in the upstream portion of the gas pipe in a branched manner, and the actual flow rate check is provided in the check pipe or the downstream portion of the gas pipe. The mass flow meter is provided.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

 FIG. 1 is a schematic diagram of the first embodiment of the present invention.

The semiconductor substrate 4 is introduced from the transfer chamber 12 connected to the gate valve 11 into the processing chamber 3 which is kept in vacuum by the high vacuum pump 8 and the roughing vacuum pump 13 via the main valve 10 and is placed on the electrode. Retained. The process gases A, C, D are introduced into the processing chamber 3 by gas pipes having MFCs 2A, 2C, 2D, respectively. Then, in particular, a check pipe provided with a mass flow meter 7 for flowing the check inert gas B in the upstream portion of the MFC 2A of the gas pipe for introducing the process gas A.
20 are provided.

Next, the gas flow in the first embodiment configured as described above will be described.

The process gas A, which requires the actual flow rate check, opens the gas valves 1a, 1b, 1c when performing etching, and the MFC2
Flow through A into the processing chamber 3 to etch the semiconductor substrate 4. The flow rate of the process gas A at this time is controlled by the MFC through the MFC flow controller 6 from the flow rate controller 5.

When checking the actual flow rate of the MFC 2A, the gas valves 1a and 1c are closed and the gas valves 1d and 1e are opened. Then, the check inert gas B is sent in the order of MFM7, MFC2A, and gas valve 1e, and flows to the intake side of the high vacuum pump 8. At this time, the flow rate signal controlled by the MFC 2A is sent to the MFC flow controller 6, and at the same time, the flow rate signal measured by the MFM 7 is sent to the MFM flow panel 9. MFC2A, MFM
The signal of 7 is further sent to the flow control device 5, where the MFC is
The flow rates of 2A and MFM7 are checked. A specific actual flow rate check method will be further described.

First, M from the flow controller 5 to the MFC flow controller 6
A signal to send an arbitrary flow rate (for example, 0cc, 10cc, 20cc, 30cc, etc.) within the flow rate below the full scale of FC2A is automatically sent. Inert gas B flowing in the pipe when each arbitrary flow rate is flown
Measure the flow rate with MFM7. Due to this measurement signal, only the flow rate is displayed on the MFM flow panel 9, and the signal of the MFM 7 is further sent to the flow rate control device 5. In this flow control device 5, MFC2
Check the flow rate by comparing the signal sent to A and the signal sent from MFM7. The check result is graphed by the flow rate control device 5, and if it is out of the set standard, an error is displayed and the operator waits for processing, and the operation of product processing cannot proceed.

The timing of the actual flow rate check is the process gas A
When there is no need to control the pressure in the processing chamber 3 without flowing
That is, the gas valve 1c and the main valve 10 are closed. For example, the actual flow rate can be checked while the gate valve 11 is opened and the semiconductor substrate 4 is being transferred between the transfer chamber 12 and the processing chamber 3.

 FIG. 2 is a schematic diagram of the second embodiment of the present invention.

In the second embodiment, the MFM7 is installed on the downstream side of the gas valve 1e, and the check pipe for flowing the check gas B into the pipe for introducing the process gases A, C, D is further provided.
20 connected.

According to the second embodiment configured in this way, the MFC2A,
There is an advantage that the actual flow rate can be checked with one MFM7 for the process gas whose gas flow rate is controlled by 2C and 2D.

〔The invention's effect〕

As described above, according to the present invention, by providing a mass flow meter for checking the actual flow rate and a check piping for flowing the check gas in the process gas piping, it is possible to easily check the actual flow rate of the mass flow controller. The effect is that troubles such as clogging of the controller piping and malfunction can be detected early.

[Brief description of drawings]

1 and 2 are schematic views of the first and second embodiments of the present invention, and FIG. 3 is a schematic view of a conventional example. 1a to 1i …… Gas valve, 2A, 2C, 2D …… MFC, 3 …… Processing chamber, 4 …… Semiconductor substrate, 5 …… Flow control device, 6 …… MF
C Flow controller, 7 ... MFM, 8 ... High vacuum pump, 9 ... MFM flow panel, 10 ... Main valve, 11
...... Gate valve, 12 …… Transfer chamber, 13 …… Roughing vacuum pump, 14 …… High frequency power supply, A, C, D …… Process gas,
B ... Inert gas.

Claims (1)

(57) [Claims] 1. A plasma etching apparatus having a processing chamber for holding a semiconductor substrate and performing an etching process, a gas pipe for feeding an etching gas to the processing chamber, and a mass flow controller provided in the gas pipe. In the above, a check pipe for flowing an inert gas for checking an actual flow rate is provided at an upstream portion of the gas pipe in a branched manner, and a mass flow meter for checking an actual flow rate is provided at a downstream portion of the check pipe or the gas pipe. A plasma etching apparatus comprising: