TW201334022A - Gas distribution system and authentication method applied to plasma processing apparatus - Google Patents

Abstract

A gas distribution system and an authentication method applied to a plasma processing apparatus are disclosed, wherein, by adding a shunted channel onto one of the at least two gas channels the present invention is capable of calculating the actual flow of an un-shunted channel through measuring the atmospheric pressure of the reaction chamber. By comparing the actual measured value with the post-shunting theoretic measurement value, the working conditions of a gas shunt regulator can be determined, in which the test values can be measured multiple times in the same channels to obtain high-precision accuracy data, or a measurement can be carried out on one channel, followed by a re-measurement on the output airflow of the gas supply source or another gas channel, the re-measurement value and the first measurement value are compared to offset the influence caused by variables such as temperature.

Description

Gas distribution system and verification method applied to plasma processing device

The present invention relates to the field of semiconductor manufacturing, and more particularly to a multi-channel gas distribution system applied to a plasma reaction chamber.

Plasma processing equipment is required for semiconductor equipment. Plasma equipment includes RF supply systems and gas supply systems. As wafer sizes are now generally 12 inches, even larger sizes are under development. In order to obtain a uniform processing effect in a large-area plasma reaction chamber, it is necessary to supply different flow rates of gas to different regions of the reaction chamber to offset the different processing effects caused by other hardware parameters. A plurality of reaction gases are precisely controlled by a flow controller (MFC) connected in series on each gas, and finally mixed into a reaction gas through a mixing chamber. After the mixing is completed, the pipes or chambers which are isolated from each other are distributed to different gas supply regions, and the separated reaction gases have a set ratio. Nowadays, the industry often uses the same plasma processing equipment, such as a plasma etching machine, to process a variety of different processes. To achieve the best processing results when performing different processing, the processing gas flowing onto the wafer has different flow rates. proportion. However, the flow rate of the mixed gas in front is precisely controlled by MFC. The ratio of the gas flow rate to different reaction zones is not accurately measured or verified. If there is a deviation or the offset after long-term use, the corresponding processing effect will be synchronized. deviation. Therefore, the prior art requires a system or method to accurately measure the shunt accuracy of the shunt.

In view of the above problems in the background art, the present invention proposes a gas distribution system applied to a plasma reaction chamber and a verification method thereof.

The invention discloses a gas distribution system applied to a plasma processing device, the plasma processor comprising a reaction chamber and a gas distributor, the gas distributor comprising at least two independent gas distribution regions for supplying treatment to different regions of the reaction chamber a gas, an air suction device is connected to the reaction chamber to discharge the processing gas in the reaction chamber; a gas supply source supplies the control gas at a controlled flow rate; and a gas flow divider is received and processed through the gas supply passage connected to the gas supply source a gas splitter that splits the process gas and supplies it to two separate gas distribution zones of the gas distributor through first and second gas passages; the first gas passage further includes a first switching valve connected to the gas The reaction chamber, and a bypass passage, are connected to the suction device through a first bypass switch valve.

The second gas passage includes a second switching valve connected to the reaction chamber, and a bypass passage is communicated to the suction device through a second bypass switch valve.

The invention can also be used to divide the reaction gas gas stream into three ways to supply at least three zones of the reaction chamber, in which case at least two or more actual gas flows are required to obtain an accurate gas flow distribution ratio, so at least two of them. The gas passages should include a bypass passage. For example, the first pass through the reaction chamber is supplied with air, and the second and third paths each include a switchable bypass passage connected to the air suction device. After setting the gas flow distribution ratio, first bypass the gas of the second third path, and measure the flow rate of the first gas passage by measuring the reaction gas pressure once or twice according to the foregoing method; secondly bypassing the third gas passage, again The measured values of the flow rate in the first and second passage opening conditions are measured and obtained. The flow rate of the second path can be obtained by subtracting the two. The flow value of the third passage can be obtained by subtracting the measured values of the first and second flows from the total flow value. The partitioning of other more airflows can also be verified in the same way. Of course, it is better to connect each of the gas passages of the two or more gas splitting outlets to a bypass passage. The test sequence and method may have More choices.

The specific embodiments of the present invention will be further described by the following examples and the accompanying drawings.

100‧‧‧reaction chamber

10‧‧‧ gas supply

11‧‧‧ Valve

20‧‧‧ gas shunt regulator

210‧‧‧ Valve

211‧‧‧ Valve

220‧‧‧ valve

221‧‧‧ Valve

1 is a system structural diagram of an embodiment of the present invention

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view showing the structure of a gas distribution system for a plasma processing apparatus of the present invention. A gas supply source 10 provides one or more gases at a controlled flow to mixing ratio. A plurality of gas flow controllers within the gas supply 10 can precisely control and regulate different gas flows. The reaction gas output from the gas supply source 10 flows to a downstream gas split regulator 20, and the output reaction gas is divided into at least two outputs to be supplied to different regions of the downstream reaction chamber 100. The reaction gas supplied to the first region of the reaction chamber is connected to an output of the gas split regulator through the first gas conduit. The reaction gas supplied to the second region of the reaction chamber is connected to the other output end of the gas ratio regulator through the second gas conduit. By controlling the output gas flow ratio of the two output ends of the gas split regulator, it is possible to adapt to the different distribution requirements of the reaction gas in the reaction chamber 100 by different processing processes. Each of the first and second gas conduits further includes a valve 210, 220 that can be controlled to open and close. A bypass gas line is also included at the front end of the valve inflowing gas, and is connected to the suction device through a controllable opening and closing bypass valve 211, 221. In addition, upstream of the gas split regulator, a valve 11 for controlling opening and closing is connected to the suction device.

In the operation of the gas distribution system for a plasma processing apparatus of the present invention, two modes are included: a plasma processing mode and a gas flow verification mode. Disconnecting the valves 11, 211, 221 in the plasma processing mode while closing the valves 210 and 220 such that the entire reaction chamber outputs a certain ratio of gas to different regions of the reaction chamber 100 according to the gas shunt regulator, flowing through the first The gas of the gas pipe and the second gas pipe may be 50%: 50% or 30%: 60%, and any ratio may be used. In the airflow verification mode, in order to verify whether the gas split regulator splits the reaction gas at a set rate, it is necessary to flow at least one gas bypass between the exhaust devices to verify. For example, to verify the flow rate through the first gas pipeline, when the upstream gas flow output is 2000 sccm, if the gas split regulator is set to a ratio of 1:1, the first gas flows accurately. The flow rate of the body pipe should be 1000 sccm. At this time, the valve 210 can be opened, the valve 211 is opened to allow the reaction gas in the first gas pipe to flow into the reaction chamber, and the opening valve 221 is opened 220 to prevent the reaction gas in the second gas pipe from flowing into the reaction chamber and directly flowing into the air suction device. This has the same operating state for the gas split regulator 20 as in the plasma processing mode, and the two gases do not interfere with each other, interfering with the measurement results.

The flow rate through the first gas line can be measured using the formula of PV = nRT. Wherein P represents the gas pressure in the reaction chamber, and V represents the volume of the container in the present invention, that is, the internal space of the reaction chamber, which is a fixed value that can be measured. n represents the amount of gas, which is the product of flow and time, which varies with time and flow. R is a constant that embodies the proportional relationship between different parameters. T refers to the temperature of the reaction chamber, and the gas pressure of the gas increases as the temperature inside the reaction chamber increases.

When measuring the flow rate through the first gas pipe, the gas is supplied to the reaction chamber at the above 1000 sccm, and after a certain time, for example, 10 seconds or 30 seconds, the theoretical gas amount is obtained, and then the temperature value in the reaction chamber is measured. The formula PV=nRT The theoretical pressure P value in the reaction chamber can be known that the flow rate of the gas split regulator 20 on the first gas pipe can be known by comparing the measured gas pressure with the barometric pressure meter having the reaction chamber itself. Is it accurate? Since the total flow rate of the inflow gas split regulator is known, the measured flow rate Xsccm is alleviated, and the flow rate through the second gas pipe is (2000-X) sccm.

Since the airflow from the front-end gas supply source may also have a slight error, such as the set value is 2000sccm, the actual value may be offset between 1950~2050, in order to offset the theoretical value with error and the actual measured flow value. The problem is that the flow rate of the output gas of the gas supply source 10 can be measured at the same time. During the measurement, the valves 210, 220 can be opened at the same time, or one of them can be turned off to ensure that the valves 211, 221 are disconnected so that all the gas flows into the reaction chamber, and the measured flow rate is obtained by the above-mentioned method of measuring the gas pressure, and then compared with the measured value after the gas splitting. If the split is 50% of the total airflow, the two values should also be 1:50%, otherwise the gas There is an error in the shunt regulator.

In some cases, the temperature value T is unstable. For example, when the power is turned on and after a long period of operation, the temperature in the reaction chamber changes greatly, which may cause the actual measured air pressure deviation to cause misjudgment. In order to offset this error, the split ratio of the gas split regulator can be adjusted after completing one measurement, for example from 50%:50% to 40%:60%, again. Since the two measurement times are short apart, the temperature hardly changes, so the ratio of the theoretical air pressure P1=n1RT/V measured for the first time to the theoretical air pressure P2=n2RT/V for the second time measurement P1: P2=n1 :n2, so in the case where the gas inflow time is known, the measured air pressure ratio is the ratio of the two measured flows. That is, if the measured air pressure ratio is 50% of the theoretical ratio: 40%, it means that the gas shunt regulator works normally.

In addition to testing the first gas line at two different flow ratios, it is also possible to measure the operation of the gas split regulator in the second gas line. As with the measurement of the first gas conduit, in this case the valve 210 needs to be closed and the valve 211 is opened to allow the first conduit gas to flow directly into the extraction device. At the same time, the valve 220 is opened, and the valve 221 is closed to allow the gas in the second gas pipe to directly flow into the reaction chamber. Then, the same method as testing the first gas pipe is used to obtain the actually measured flow rate according to the magnitude of the reaction chamber air pressure, and then compared with the set theoretical value to finally determine whether the gas shunt regulator works normally.

The invention adds a bypass channel to one of the at least two gas channels, and can calculate the actual flow rate of the unbypassed gas channel by measuring the reaction chamber pressure according to the reaction chamber gas pressure measured in the public PV=nRT. By comparing the actual measured value with the theoretical measured value after the split, the operation of the gas split regulator can be judged. The test value may be that the measurement is performed multiple times on the same channel to obtain high-precision data, or the measurement of one channel may be performed on the output airflow of the gas supply source 10 or another gas channel, and the measurement will be performed again. The value is compared to the first measurement to counteract the effects of variables such as temperature.

The invention can also be used to divide the reaction gas gas stream into three channels to the reaction chamber. In embodiments of at least three zones, it is necessary to test at least two or more actual gas flows to obtain an accurate gas flow distribution ratio, so at least two of the gas channels include a bypass passage. For example, the first pass through the reaction chamber is supplied with air, and the second and third paths each include a switchable bypass passage connected to the air suction device. After setting the gas flow distribution ratio, first bypass the gas of the second third path, and measure the flow rate of the first gas passage by measuring the reaction gas pressure once or twice according to the foregoing method; secondly bypassing the third gas passage, again The measured values of the flow rate in the first and second passage opening conditions are measured and obtained. The flow rate of the second path can be obtained by subtracting the two. The flow value of the third passage can be obtained by subtracting the measured values of the first and second flows from the total flow value. The partitioning of other more airflows can also be verified in the same way. Of course, it is better to connect each of the gas passages of the two or more gas splitting outlets to a bypass passage. The test sequence and method may have More choices.

Although the present invention has been described in detail by the preferred embodiments thereof, it should be understood that the foregoing description should not be construed as limiting. Various modifications and alterations of the present invention will be apparent to those skilled in the art. Therefore, the scope of the invention should be limited by the scope of the appended claims.

100‧‧‧reaction chamber

10‧‧‧ gas supply

11‧‧‧ Valve

20‧‧‧ gas shunt regulator

210‧‧‧ Valve

211‧‧‧ Valve

220‧‧‧ valve

221‧‧‧ Valve

Claims (8)

A gas distribution system applied to a plasma processing apparatus, the plasma processor comprising a reaction chamber and a gas distributor, the gas distributor comprising at least two independent gas distribution regions for supplying processing gas to different regions of the reaction chamber, An air suction device is connected to the reaction chamber to discharge a processing gas in the reaction chamber; a gas supply source supplies a control flow of the processing gas; and a gas flow divider is connected to a gas supply passage of the gas supply source Receiving a process gas; the gas splitter splits the process gas and supplies it to two independent gas distribution zones of the gas distributor through a first gas passage and a second gas passage; wherein the first gas passage further A first switching valve is coupled to the reaction chamber, and a bypass passage is coupled to the extraction device via a first bypass switch valve. The gas distribution system applied to the plasma processing apparatus according to claim 1, wherein the gas flow divider further comprises a third gas passage connected to the reaction chamber through a third switching valve, and a bypass passage through A third bypass switch valve is coupled to the aspirator. A gas distribution system applied to a plasma processing apparatus according to claim 1, wherein the second gas passage includes a second switching valve connected to the reaction chamber, and a bypass passage through a second bypass switch valve Connected to the aspirator. A verification method applied to a gas distribution system of a plasma processing apparatus, the plasma processor comprising a reaction chamber and a gas distributor, the gas distributor comprising at least two independent gas distribution regions supplying different regions of the reaction chamber Processing gas, a gas shunt regulator supplies gas to at least two gas distribution regions of the gas distributor through at least two gas passages, and an air suction device is connected to the reaction chamber to discharge the treatment in the reaction chamber gas; Providing a processing gas having a set flow value; diverting the processing gas having the set flow value into a first partial processing gas and a second partial processing gas, causing the first portion of the processing gas to flow into the reaction chamber, the first a two-part process gas directly flows into the pumping device; measuring a first portion of the gas pressure flowing into the reaction chamber, and calculating the first portion of the process gas flow rate; and comparing the measured first portion of the gas flow rate value with a gas flow reference And determining a shunt state of the gas shunt regulator, wherein the airflow reference value is the set flow value. A verification method applied to a gas distribution system of a plasma processing apparatus, the plasma processor comprising a reaction chamber and a gas distributor, the gas distributor comprising at least two independent gas distribution regions supplying different regions of the reaction chamber Processing gas, a gas shunt regulator supplies gas to at least two gas distribution regions of the gas distributor through at least two gas passages, and an air suction device is connected to the reaction chamber to discharge the treatment in the reaction chamber a gas; providing a processing gas having a set flow value; diverting the processing gas having the set flow value into a first partial processing gas and a second partial processing gas, causing the first portion of the processing gas to flow into the reaction chamber The second portion of the process gas flows directly into the pumping device; the gas pressure of the reaction chamber is measured, and the first portion of the process gas flow rate is calculated; and the first portion of the gas and the second portion of the process gas ratio are adjusted again. Calculating the gas pressure of the reaction chamber, calculating the gas flow rate of the first portion; comparing the values obtained by two measurements The shunt regulator bypass gas state. The verification method applied to the plasma processing apparatus gas distribution system according to claim 4, further comprising an overall air flow measuring step: Passing a first portion of the gas and a second portion of the gas output from the gas flow regulator into the reaction chamber, measuring the gas pressure of the reaction chamber and calculating an overall gas flow rate; using the overall gas flow rate as a gas flow reference value, and measuring The resulting first partial gas flow rate value is compared to determine the gas split regulator split state. The verification method applied to the plasma processing apparatus gas distribution system according to claim 4, further comprising a second partial processing gas flow rate measuring step: the first partial gas outputted by the gas distribution regulator directly flows into the air suction device a second portion of the gas flows into the reaction chamber, the reaction chamber gas pressure is measured and the second portion of the process gas flow rate is calculated; and the second portion of the process gas flow rate is used as a flow rate reference value and the first portion of the process gas flow rate is compared Determining a shunt state of the gas shunt regulator. The verification method applied to the gas processing system of the plasma processing apparatus according to claim 4 or 5, wherein the plasma processing mode is entered after determining that the gas shunt regulator is in a normal state, and the reaction chamber is different according to the process requirement. The area is supplied with a reaction gas that sets the flow rate.