KR20050061118A - Semiconductor processing apparatus using rf power - Google Patents

Abstract

A semiconductor processing apparatus using RF power is provided. The semiconductor processing apparatus efficiently measures the reflected power reflected from the process chamber by the RF power applied in the process and stops the entire process at the abnormal limit value of the semiconductor processing apparatus with respect to the reflected power. The control circuit part which protects a board | substrate is provided.

Description

Semiconductor processing apparatus using RF power

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor processing apparatus, and more particularly, to a semiconductor processing apparatus using radio frequency (R.F.) power.

When introduced into a process apparatus for processing semiconductor substrates using RF power, the process gas is ignited with plasma in response to an RF or electromagnetic field. The RF field is supplied by a reactive impedance element, typically an array of electrodes or a coil, coupling both the magnetic and electrostatic RF fields with the process gas. The reactive impedance element is connected to an RF power signal generator having a frequency and sufficient power so that the gas is ignited with the RF plasma. The connection between the RF power signal generator and the reactive impedance element is usually made by a matching network using relatively long coaxial cables. The matching circuit includes a pair of variable reactances that are tuned to control the tuning of the load including the reactive impedance element and RF plasma and to match the load driving the impedance of the RF power signal generator. When the match is reached, the impedance seen by examining the RF power signal generator output termination is approximately equal to the impedance observed in the cable.

The load represented by the RF power signal generator is subject to substantial changes. The load is relatively high impedance before the gas is ignited in the RF plasma state. In response to the ignited plasma, the load impedance is substantially lowered due to the presence of charge carriers, ie electrons and ions, in the excited plasma.

The ignited plasma impedance also changes substantially due to changes in the plasma flux that are a result of the plasma density and the plasma charge particle velocity. However, it is rather difficult to match the RF power signal generator to the load in order to provide effective power transfer from the RF power signal generator to the load.

Since matched circuit reactances change at the same time to perform matching, the plasma often becomes unstable and the flux of the plasma changes its amplitude unpredictably.

1 is a block diagram illustrating a power flow of a semiconductor processing apparatus using RF power.

As shown in FIG. 1, the RF signal of the RF power signal generator 101 is incident to the matching circuit 102 before being incident to the process chamber 103. The matching circuit 102 is a load facing the process chamber 103 from the RF generator 101, and adjusts the load between the generator 101 and the chamber 103 to transfer the maximum power, uniformity and reflected power of the RF plasma. To protect the process line from the circuit. However, as described above, this matching operation is difficult to predict due to a change in plasma flux, which is a result of plasma density and plasma charge particle velocity. The conventional semiconductor substrate processing apparatus directly displays the value of the reflected power on the monitor 104 so that the user 105 can know the state of the process chamber 103. However, when the value displayed on the monitor 104 is greater than the threshold value or the semiconductor device may be damaged, the user may be inadvertently aware of the process and proceed with the process.

2 is a flowchart illustrating a method of controlling power flow of a conventional semiconductor processing apparatus.

Referring to FIG. 2, the start of the semiconductor processing apparatus 100 starts as a definition of the user 105 (S101). Step S101 is a manual input step in which the user inputs the RF power signal according to the optimum condition of the process. Step S102 is a step of signal generation and signal transmission in the RF power signal generator with a manual input in S101. Step S103 represents a sensing step in the matching circuit. Step S104 is a step of monitoring the sensed signal in step S103, which continues to S101. As shown in the regulation of the conventional power flow, it can be seen that the semiconductor processing apparatus can control the movement only by the manual signal of the user. The disadvantage of such equipment is that even if the reflected power value is above the threshold value or the value of the semiconductor device may be damaged, it may not be detected due to user's carelessness and the operation of the process equipment may be continued to damage the device and the semiconductor substrate.

The present invention displays the reflected power value in the process chamber to which the RF power is applied to the monitor and detects the occurrence of the critical reflected power that can affect the entire semiconductor substrate process line and forcibly stops the process line. It is to provide a semiconductor processing apparatus.

In the semiconductor processing apparatus according to the present invention for achieving the above technical problem, the RF power generator for generating the RF power, the process chamber in which the RF power is applied from the RF power generator to produce a semiconductor substrate, RF power A matching circuit unit for matching respective loads between the process chamber and the process chamber, a current sensing unit for measuring the reflected power reflected from the process chamber at the matching circuit unit, a monitor for numerically notifying the measurement signal of the current sensing unit, and a measurement signal of the current sensing unit. And a control circuit unit capable of receiving and holding or stopping a process made in the process chamber.

Specific details of other embodiments are included in the detailed description and the drawings.

Advantages and features of the present invention, and methods of achieving the same will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and the present embodiments are intended to complete the disclosure of the present invention, and those skilled in the art to which the present invention pertains. It is provided to fully inform the scope of the invention, and the invention is defined only by the claims. Like reference numerals refer to like elements throughout.

FIG. 3 is a block diagram conceptually illustrating power movement between an RF power signal generator and a process chamber constituting a semiconductor processing apparatus according to an embodiment of the present invention, and a relationship thereof.

Referring to FIG. 3, a semiconductor processing apparatus according to an exemplary embodiment of the present invention may include an RF power signal generator 301 and a process chamber 303, and may be disposed between the RF power signal generator 301 and the process chamber 303. The matching circuit unit 302 is connected to adjust the transfer state of the RF power. The matching circuit unit 302 includes a current sensing unit 304 formed of a PCB RF sensor for sensing the reflected power 309 as a current signal therein. The current signal 311 is transmitted from the current sensing unit 304 to the monitor 305 and the control circuit unit 314. The signal transmitted to the monitor 305 is monitored as a signal 312 identifiable by the user 306, and the user controls the semiconductor processing apparatus 300 based on this signal 312.

The control circuit unit 314 receives the current signal 311 from the current sensing unit 304 in the same manner and transmits the same to the RF power signal generator 301 and the process chamber 303 of the semiconductor processing apparatus 300 as a constant signal. Transmit hold / stop signal.

In detail, the RF power signal generator 301 generates an electric field that changes with time in the process chamber 303 by using an RF power source, which is a high frequency voltage source, thereby exciting gas. Signal to generate / maintain plasma. The electrical impedance inside the process chamber 303 has an element that can be changed by the environment formed inside the process chamber 303. In particular, in the case of a plasma chamber to which a high frequency voltage source is applied, such a variable factor is large. Done.

For example, in the case of performing a sputtering process with a target used as a deposition material, the impedance inside the chamber changes as the target is corroded.In the etching or ashing process, the inside of the chamber with respect to the size and required etching rate of the substrate to be processed Depends on gas concentration, temperature, etc. The ideal high frequency matching in the chamber system is such that the internal impedance of the RF power signal generator 301 and the internal impedance of the process chamber 303 are equal. To this end, the matching circuit 304 matches the impedances of the RF power signal generator 301 and the process chamber 303 to increase the utilization of power. As shown in FIG. 3, the incident power 307 is applied to the process chamber 303 as the incident power 308 at a predetermined magnitude through the matching circuit unit 304. However, even if the matching circuit unit 303 from the RF power signal generator 301 facilitates impedance matching, the reflected power 309 in the process chamber 303 is present due to the above-described causes. In this case, the matching circuit unit 302 drives the current sensing unit 304 in the matching circuit unit 302 to protect the semiconductor processing apparatus 300 to measure the reflected power 309 as a current amount. The sensed current signal 311 is transmitted to the monitor 305 and the control circuitry 314. The signal at the monitor 305 is known to the user 306 as a signal 312 that can be identified by the user. At this time, the user 306 manually adjusts the incident power 307 of the RF power signal generator 301 of the semiconductor processing apparatus 300 again to achieve an optimal environment for the process. In addition, the current signal 311 from the current sensing unit 304 is transmitted to the control circuit unit 314 in addition to the monitor 305. In the control circuit unit 314, the reflected power 309 of the process chamber 303 is processed into the process chamber. Any threshold based on the incident strength 308 applied to the 303, the matching circuit 302, and the RF power signal generator 301 can withstand or exceeds the threshold, and the user 306 may exceed it. If it is not recognized, the control circuit unit 314 generates a signal forcibly driving the semiconductor processing apparatus 300. This signal is a signal for holding / stopping the process of the semiconductor processing apparatus 300 based on the threshold value. In addition, the control circuit unit 314 is distinguished from the monitor 305 and is driven only as the current signal 311 of the PCB RF sensor 304, and becomes a final circuit unit that protects the semiconductor processing apparatus 300.

4 is a flowchart illustrating a method of controlling power flow of a semiconductor device according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described in more detail with reference to FIG. 4.

The start of the semiconductor processing apparatus 300 begins with the definition of the user 306.

Step S401 is a manual input step of inputting the RF power signal according to the optimum conditions of the user's process. Step S402 is a step of signal generation and signal transmission in the RF power signal generator according to the manual input. In step S403, a sensing step of the PCB RF sensor, which is the current sensing unit 304 in the matching circuit unit 302, is shown. In step S404, the sensed signal in step 3 is monitored 305, which is followed by step S401. As a result of the monitoring, when the reflected power exceeds the threshold, the device is manually stopped (S401 and S405). In step S406, the control circuit unit 314 receives a signal sensed by the current sensing unit 304 in the matching circuit unit 302 and operates in step S403. Any threshold based on the incident power 308 that is applied to the process chamber 303 and the history strength that the matching circuit 302 and the RF power signal generator 301 can withstand is applied to the process chamber 303. The semiconductor processing apparatus 300 is automatically stopped when a loop is performed in step S406 to maintain the process compared with the value or when the compared signal is greater than or equal to a threshold value. The incident power 308, the matching circuit 302, and the RF power signal generator 301 to which the reflected power of the semiconductor processing apparatus 300 is applied to the process chamber 303 are provided by the forced stop step S407. When the threshold value is exceeded based on the withstand strength, it serves to protect the semiconductor processing apparatus 300.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may be embodied in other specific forms without changing the technical spirit or essential features of the present invention. I can understand. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

The semiconductor processing apparatus according to the present invention includes a semiconductor processing apparatus and a process including a control circuit unit capable of efficiently measuring the reflected power reflected from the process chamber during the process to stop the whole process at the abnormal limit value of the semiconductor processing apparatus with respect to the reflected power. The semiconductor substrate can be protected safely.

1 is a block diagram showing a power flow of a semiconductor processing apparatus using a conventional RF power.

2 is a flowchart illustrating a method of controlling power flow of a semiconductor processing apparatus using conventional RF power.

3 is a block diagram illustrating a power flow of a semiconductor processing apparatus using RF power according to an embodiment of the present invention.

4 is a flowchart illustrating a method of controlling power flow of a semiconductor processing apparatus using RF power according to an embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

300: semiconductor processing apparatus 301: RF power signal generator

302: matching circuit part 303: process chamber

304: current sensing unit 305: monitor

306: user 307: incident power to the matching circuit

308: incident power to the process chamber 309: reflected power

311: current signal 312: user identifiable signal

313: user control signal 314: control circuit

315: hold / stop signal

Claims (2)

An RF power generator for generating RF power; A process chamber in which an RF power is applied from the RF power generator to produce a semiconductor substrate; A matching circuit for matching respective loads between the RF power and the process chamber; A current sensing unit measuring reflected power reflected from the process chamber in the matching circuit; A monitor device for numerically informing the measurement signal of the current sensing unit; And And a control circuit unit capable of holding or stopping the process made in the process chamber in response to the process signal of the current sensing unit. The semiconductor processing apparatus of claim 1, wherein the control circuit unit stops the process chamber when the reflected power is greater than or equal to the monitor device to stop the process chamber.