KR102170403B1 - Apparatus and method for monitoring plasma process - Google Patents

Abstract

The present invention relates to an apparatus and a method for monitoring a plasma process. The present invention includes: an optical sensor module installed in a reaction chamber of the plasma process and sensing light from a light source unit; the light source unit irradiating the inside of the reaction chamber with monitoring light in accordance with control by a main control unit; and the main control unit controlling the operation of the plasma reaction chamber by analyzing the measurement result of the optical sensor module. The optical sensor module senses the light from the light source unit and includes a light sensor module including a color sensor sensing a specific ion or radical difference caused by the light emitted by the light source unit and an automatic gain adjustment amplifier amplifying a signal from the color sensor by using the amplification time constant by stage received from a self-stage recognition unit and adjusting the amplification gain in accordance with each process stage. The main control unit includes the self-stage recognition unit. The self-stage recognition unit determines which stage corresponds to the current region in the total plasma process recipe, calculates a tailored amplification time constant corresponding to the stage, and provides it to the automatic gain adjustment amplifier. According to the present invention, even a plasma-less process can be appropriately monitored. In addition, it is possible to sense in real time a fine process change regardless of the process recipe having a large inter-process stage plasma flux in the plasma process. As a result, it is possible to achieve detailed and sophisticated plasma process monitoring and control.

Description

Plasma process monitoring device and method {APPARATUS AND METHOD FOR MONITORING PLASMA PROCESS}

The present invention relates to a plasma process monitoring apparatus and method, and more specifically, a pumping process that does not generate plasma in a plasma process composed of multiple stages, an etching process using radicals, a deposition process, and a cleaning process while monitoring each process step. The present invention relates to an apparatus and method for monitoring a plasma process to enable precise and detailed process control by detecting minute process changes in real time despite process recipes having a large difference in plasma flux between them.

In general, the manufacturing process of a semiconductor integrated circuit is composed of various unit processes such as a cleaning process, an ion implantation process, a photo process, a deposition process, an etching process, and chemical mechanical polishing.

Among the manufacturing processes of semiconductor integrated circuits, the plasma process is an essential process for manufacturing micro semiconductor integrated circuits, and is currently widely used for various surface treatment processes including etching and deposition processes in semiconductor and display panel production. In the etching process using plasma, the unpredictable change of the process input parameter may affect the line width of the fine pattern and the inclination of the sidewall, thereby preventing accurate and fine implementation of the integrated circuit. Therefore, there is a need for a plasma process monitoring method capable of observing the presence or absence of an abnormality occurring during the plasma process in real time and accurately confirming.

Until now, technologies for plasma process monitoring include Langmuir Probe using electrostatic probes, Self-Excited Electron Spectroscopy (SEERS), and plasma process monitoring using light. Optical Emission Spectroscopy (OES), etc. are being used. However, the Langmuir probe method has a disadvantage in that the sensor is inserted inside the reaction chamber and the metal tip is exposed to plasma, and the luminescence analysis method (OES) is derived in a format that makes it difficult to intuitively interpret or judge the measurement result, and the amount of data is vast. As a result, the sampling rate is limited, and the SEERS technology has a limitation in that the sensitivity of the sensor is lowered, so it is difficult to accurately and quickly grasp the state of the plasma process.

On the other hand, in determining the sensitivity of the photosensor for detecting the state of the plasma process, conventionally, regardless of the process step, the entire process has been fixed as one amplification gain and used. In this method, even if there is a plasma deviation in each step, the focus is on an important region or the sensitivity is adjusted based on the step with the highest plasma intensity. For example, as shown in FIG. 1, assuming that the plasma process proceeds from step 1 to step 4 (S1, S2, S3, S4), based on the amplifier gain in the third step (S3) If the gains of all steps are set equal, low signals such as the second step (S2) and the fourth step (S4) cannot be properly expressed. Conversely, if the fourth step (S4) is set as a reference, In the third step (S3 area), a problem of being saturated is bound to occur.

Due to this phenomenon, according to the conventional method of monitoring the stage with the strongest plasma intensity, cleaning of a remote plasma source (RPS), comparison of conditions before/after discharging wafers, and a cleaning process with relatively weak plasma intensity. Since it becomes almost impossible to observe minute changes in the process such as, there is a serious problem in that it is impossible to precisely monitor and analyze the entire steps of the plasma process.

KR 1020120141027 A

The present invention is to solve the problems of the prior art described above, and one object of the present invention is to accurately detect abnormal state of plasma in the reaction chamber in real time by detecting minute changes in all steps in the plasma process recipe. It is to provide a plasma process monitoring apparatus and method capable of.

Another object of the present invention is to monitor the difference due to radicals or ions inside the chamber by supplying the light source itself to the pumping process, the etching process using radicals, the deposition process, and the cleaning process in which plasma does not occur because RF power is not supplied. It is to provide a plasma process monitoring apparatus and method capable of accurately monitoring the entire process.

Another object of the present invention is to provide a plasma process monitoring apparatus capable of securing flexibility of a device structure by independently configuring an optical sensor module or integrally configuring an optical sensor module on a master board.

One aspect of the present invention for achieving the above object,

An optical sensor module installed in the reaction chamber of the plasma process to detect light emitted from the light source unit;

A light source unit for irradiating monitoring light into the reaction chamber according to the control of the main control unit; And

And a main control unit for controlling the operation of the plasma reaction chamber by analyzing the measurement result of the optical sensor module,

The optical sensor module detects the light emitted from the light source and uses a color sensor that detects a difference between specific ions or radicals due to the light irradiated by the light source and an amplification time constant for each step received from the self-step recognition unit. Including an optical sensor module consisting of an automatic gain adjustment amplifier that amplifies the signal from the color sensor and adjusts the amplification gain according to each process step,

Wherein the main control unit includes a self-step recognition unit that determines which stage of the entire plasma process recipe corresponds to the current region, calculates an amplification time constant suitable for the corresponding stage, and provides it to the automatic gain adjustment amplifier. It relates to a monitoring device.

In the present invention, the optical sensor module and the main control unit may be installed independently of each other, or may be integrated into one master board, and the optical sensor module may be installed in a viewport of a plasma reaction chamber.

The optical sensor module includes an optical sensor module consisting of a plurality of RGB sensors consisting of an R-channel sensor, a G-channel sensor, and a B-channel sensor, or a single element, and the optical sensor module is a photodiode, a phototransistor, or a photo vacuum tube. It can be a type.

The main control unit may include an A/D converter for converting a light sensing signal generated from an optical sensor module into a digital signal; A color analysis unit for converting the light sensing signal converted into a digital signal into numerically quantified RGB optical data; A comparison unit comparing the RGB optical data transmitted from the color analysis unit with the RGB optical data in a normal state; And a data storage unit for storing step-by-step reference data and process allowable range data of the plasma process.

The main control unit may further include a real-time display unit displaying process parameter related data inside the reaction chamber under the control of the main control unit.

In the plasma process monitoring apparatus of the present invention, in the color analysis unit of the main control unit, the size of the light detection signal measured from the optical sensor module is divided into R channel data, G channel data, and B channel data, and is quantified, and the comparison unit The R channel, G channel, and B channel data transmitted from the color analysis unit and the R channel, G channel, and B channel data of the process allowable range are compared for each same channel, and when comparing the data, any one of each channel data Even if it is out of the process allowable range, it may be configured to determine that the plasma in the reaction chamber has reached an abnormal state.

The apparatus may further include a warning unit that generates a warning sound or a warning light according to a signal transmitted from the main control unit.

The color analysis unit divides the size of the RGB signal measured from the optical sensor module into R-channel data, G-channel data, and B-channel data, respectively, and quantifies color data, saturation data, and brightness data through a combination of these data. And the color, saturation, and brightness data transmitted from the color analysis unit in the comparison unit and the color, saturation, and brightness data in the process allowable range are compared for each of the same type. When comparing the data, any one of each data Even if it is out of the process allowable range, it may be configured to determine that the plasma in the reaction chamber has reached an abnormal state.

Another aspect of the present invention is a method for monitoring a plasma process in the plasma process monitoring apparatus of the present invention, the method

Determining whether plasma is present in the corresponding region by the main control unit;

If it is determined that the corresponding region has no plasma, measuring the concentration of ions or radicals in the reaction chamber by irradiating monitoring light into the reaction chamber by a light source unit;

Determining which stage of the entire plasma process recipe corresponds to the current region and controlling the automatic gain adjustment amplifier to adjust the amplification time constant in the optical sensor module according to the corresponding stage; And

When amplifying the measured value from the optical sensor module, a plasma process monitoring method comprising the step of amplifying the measured value of the corresponding step using an amplification time constant suitable for each process step supplied from the self-step recognition unit It is about.

In the plasma process monitoring method of the present invention, the measured photosensitive data is divided into R-channel data, G-channel data, and B-channel data, respectively, and then quantified, and then measured in real time: R-channel data, G-channel data, and B-channel data. And determining that the plasma in the reaction chamber has reached an abnormal state when any one of them is out of the process allowable range.

The plasma process monitoring method of the present invention compares the measured hue, saturation, and brightness data with the hue, saturation, and brightness data within the process allowable range, and when any one of the data is out of the process allowable range, the reaction chamber And determining that the internal plasma has reached an abnormal state.

The plasma process monitoring method of the present invention,

A step of measuring a change amount of RGB optical data according to a process input parameter, the step of individually measuring a change amount of R channel data, G channel data, and B channel data;

Calculating and storing a reference value from RGB optical data; And

It may further include calculating the process allowable range based on the reference value.

The plasma process monitoring method of the present invention may further include generating a warning signal when it is determined that the RGB optical data value obtained during the plasma process is outside the process allowable range.

According to the present invention, it is possible to accurately monitor a pumping process that does not generate plasma, an etching process using radicals, a deposition process, and even a cleaning process by supplying a light-emitting source by itself and monitoring the difference due to radicals or ions inside the reaction chamber.

According to the present invention, in a process in which several steps in the same recipe exist, even when the difference in plasma flux by step is large, minute process changes in the chamber can be immediately detected for all steps, and plasma in the reaction chamber can be It can detect abnormal state.

In addition, according to the present invention, by detecting a minute change in a process input parameter to determine the presence or absence of a process abnormality, it is possible to prevent in advance from transferring a defective wafer caused by an error process to the next process. The defect rate of the etching process, the deposition process, and the cleaning process can be greatly reduced, and more detailed and sophisticated plasma process control can be implemented.

Further, according to the present invention, by expanding the usable range of the plasma process monitoring device, it is possible to monitor the semiconductor manufacturing process regardless of the presence or absence of plasma.

1 is a graph showing the difference in plasma flux of several steps within the same recipe of a plasma process.
2 is a schematic diagram showing a plasma process system to which a plasma process monitoring apparatus according to the present invention is applied.
3 is a block diagram of a plasma process monitoring apparatus according to an embodiment of the present invention.
4 is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention.
5 is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention.
6 is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention.
7 is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention implemented in a system-on-chip form including an optical sensor module, a main control unit, and a light source unit.
FIG. 8 is a graph of a three-dimensional representation of an RGB optical data space in a process allowable range on a 3-axis coordinate.
9 is a schematic diagram for explaining a method of measuring the amount of light output from a light source unit in a section without plasma.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

In the drawings, each component may be exaggerated for clarity. Throughout the specification, portions denoted by the same reference numerals represent the same components.

In the present specification, when a component is referred to as being "connected" or "connected" to another component, it may be directly connected or connected to the other component, but other components exist in the middle. It should be understood that it may be possible.

The terms used in the present specification are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present application, terms such as "comprise" or "comprise" are intended to designate the existence of disclosed features, numbers, steps, actions, components, parts, or combinations thereof, but one or more other features or numbers It is to be understood that it is not intended to exclude the possibility of the presence or addition of, steps, actions, components, parts, or combinations thereof.

The plasma process monitoring apparatus of the present invention may collect light generated from plasma through the viewport 140 provided on the side wall of the reaction chamber 100 during the etching or deposition process, and the collected light is an optical sensor. It is transmitted to the module 230 to measure and monitor the state of the plasma according to the plasma process process.

Referring to FIG. 2, the plasma processing apparatus includes a reaction chamber 100 forming a reaction space, a process gas injection unit 130 in which a process gas is injected into the semiconductor wafer W on the stage 110, and an RF power supply unit 120. ), etc.

The reaction chamber 100 performs a substrate processing process. For example, the substrate treatment process may be any one of various semiconductor processes such as a deposition process, an etching process, an ion implantation process, a nicking process, or a cleaning process. Each of the processes may be performed in a low vacuum/high vacuum atmosphere or an atmospheric pressure atmosphere according to process conditions. The reaction chamber 100 is a reaction space maintained in a sealed state or a vacuum state in a plasma treatment process, and has an internal space 110 of a predetermined size, and is made of a material having excellent wear resistance and corrosion resistance. A viewport 140 for observing the plasma state from the outside may be formed on the sidewall of the reaction chamber 100. Preferably, a lens (not shown) for condensing light generated from the plasma and amplifying the intensity of the light may be included.

In the present invention, the reaction chamber 100 is a plasma etching chamber, a deposition chamber, a spin-rinse chamber, a metal plating chamber, a cleaning chamber, a bevel edge etching chamber, a physical vapor deposition (PVD) chamber, a chemical vapor deposition (CVD) chamber, and ALD. It may be a (atomic layer deposition) chamber, an atomic layer etch (ALE) chamber, an ion implantation chamber, etc., but is not limited thereto.

3 is a block diagram of a plasma process monitoring apparatus according to an embodiment of the present invention, FIG. 4 is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention, and FIG. 5 is an optical sensor module of FIG. It is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention in which a main control part is included in one master board, and FIG. 6 is a N-CH optical sensor module of FIG. 6 and a main control part included in one master board. , Is a block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention.

The plasma process monitoring apparatus of the present invention includes an optical sensor module 230 attached to the viewport 140 of the reaction chamber of the plasma process to detect light emitted from the light source unit; A light source unit 400 for irradiating monitoring light into the reaction chamber according to the control of the main control unit; And a main control unit 300 for controlling the operation of the plasma reaction chamber by processing the signal transmitted from the optical sensor module 230.

The light source unit 400 may be disposed adjacent to the color sensor 231 so as to irradiate the color sensor 231 with light of a uniform amount of light. The light source of the light source unit 400 may include various members that emit light, such as an LED, a halogen lamp, a xenon lamp, and a laser device.

The light source unit 400 may irradiate standard light, which is a reference value for correcting the measurement value of the amount of light output from the optical sensor module 200. The standard light is light having a uniform amount of light, and the color sensor of the optical sensor module 230 ( The light source unit 400 is controlled to be turned on and off according to a signal from the main control unit 300, and applied by the main control unit 300 to irradiate a uniform amount of light. The voltage can be controlled.

In the period without plasma, the light source unit 400 is separated from each other with the reaction chamber interposed between the light emitting unit and the light receiving unit as shown in Fig. 9(a), and is installed in a straight line facing each other, so that the reaction chamber at the light receiving unit is The amount of light incident through is read, or as shown in Fig. 9(b), the light emitting unit and the light receiving unit are included in one module, and the light amount reflected from the reaction chamber wall is read by the light receiving unit. Can be.

The color sensor 231 detects a difference between specific ions or radicals due to the light irradiated by the light source unit 400. The amount of light reaching the color sensor 231 of the optical sensor module 230 varies depending on the amount of light absorbed by ions or radicals in the reaction chamber 100. In addition, since the absorption amount is influenced by the movement of ions or radicals in the reaction chamber, in the end, a difference occurs in the amount of light reaching the optical sensor module 230 according to the concentration of specific ions or radicals in the reaction chamber. And, using this difference, the concentration of the component to be analyzed can be calculated.

The optical sensor module 230 includes an optical sensor module composed of a color sensor 231 and a self-gain adjustment amplifier 233, and only one optical sensor module 230 may be disposed in one reaction chamber 100. , But is not necessarily limited thereto. A plurality of optical sensor modules 230 may be disposed in one reaction chamber 100 to detect light in a plurality of regions of the reaction chamber 100, respectively, and may be configured to transmit the light to the main control unit 300. In addition, the optical sensor module 230 may be disposed in each of the plurality of reaction chambers 100 and configured to transmit the light detected by each optical sensor module 230 to one main control unit 300.

In the plasma process monitoring apparatus according to the present invention, the optical sensor module 230, as shown in Figs. 3 and 4, is a structure independently installed on the side of the reaction chamber 100, or in Figs. 5 and 6 As shown, since the optical sensor module 230 is configured to be installed in the master board, which is the main control unit 300, the flexibility of the device structure can be secured.

3, in the plasma process monitoring apparatus according to an embodiment of the present invention, the optical sensor module 230 detects the light emitted from the light source unit 100 and the amplification correction received by the self-step recognition unit It includes an automatic gain adjustment amplifier 233 capable of amplifying the signal from the color sensor 231 by using the number and adjusting the amplification gain according to each process step, and the main control unit 300 is Includes a self-stage recognition unit 332 that determines which stage of the plasma process recipe corresponds to, calculates the amplification time constant in the automatic gain adjustment amplifier 233 according to the corresponding stage, and provides it to the automatic gain adjustment amplifier 233 do.

The main control unit 300 receives EMS information from the reaction chamber of the plasma process, the FDC server, or through the process information external input unit 390, for information on which stage of the entire plasma process recipe corresponds to the current area. can do. Alternatively, information on the process may be directly input from the user through the key input unit 362.

The self-step recognition unit 332 stores standard (DNA) data in a normal state, so in the etching and deposition process, the data in the current working state and the standard (DNA) data in a normal state are compared, and the tolerance range If it escapes, an alarm may occur.

The automatic gain adjustment amplifier 233 may be a programmable gain amplifier (PGA) or a voltage gain adjustment circuit (VGA).

The color sensor 231 includes a plurality of R-channel sensors, G-channel sensors, and B-channel sensors or a single device, and the color sensor 231 may be a photodiode, a phototransistor, or a photo vacuum tube type. At this time, it may be configured to extend from 2 channels to N channels at a wavelength in the range of 150 nm to 1500 nm according to the corresponding process.

The optical sensor module 230 includes the optical sensor module 230 as shown in FIG. 3 and N channels (eg, 8-channels) as shown in FIG. 4 in a certain range according to the method of dividing the light area. It can be divided into an N-CH optical sensor module 240 whose wavelength is set by size. Referring to FIG. 3, the optical sensor module 230 according to an embodiment of the present invention receives light generated from plasma gas in the reaction chamber in red, green, and blue colors by the RGB color sensor 231, and It includes an automatic gain adjustment amplifier 233 capable of amplifying the blue minute signal and adjusting the amplification gain according to each process step according to the control of the main control unit 300. The automatic gain adjustment amplifier 233 amplifies the light detected by the optical sensor module 230 by using the amplification time constant supplied from the self-step recognition unit 332 of the main control unit 300. The amplification time constant used here may be in the form of analog voltage, current/digital form in binary form.

The automatic gain adjustment amplifier 233 plays a role of amplifying by a certain amplification time constant in order to convert the light sensed by the optical sensor module 230 into an electrical signal in order to convert it into more accurate optical data, At this time, a customized amplification time constant is individually assigned for each plasma process to amplify.

On the other hand, in the structure of the RGB color sensor 231, the sensor for each RGB channel is grouped by the same acceptable color, so that the shape, which is divided into three parts of R, G, and B receiving areas, is repeated It can be provided in a structure that is. Here, since there may be a difference in sensitivity for each RGB channel, the distribution of sensors for each RGB channel disposed on the entire RGB color sensor 231 may vary, but is not limited thereto.

Referring to FIG. 4, the N-CH optical sensor module 240 of another embodiment of the present invention includes an N-CH color sensor 241 that detects light generated from plasma gas in a reaction chamber and a micro signal received as N signals. It includes an N-CH automatic gain adjustment amplifier 243 that amplifies The N-CH optical sensor module 240 may include an N-CH optical filter (not shown). 4, the N-CH optical sensor module 240 uses the signal obtained from the N-CH color sensor 241 and the amplification time constant supplied from the self-stage recognition unit 332 of the main control unit 300. Then, it amplifies through the N-CH automatic gain adjustment amplifier 243.

In addition, the RGB color signal and the N-CH color signal generated from the optical sensor module 230 and the N-CH optical sensor module 240 are analog electrical signals, and are generated without limiting the bandwidth of the signal. Different electrical signals may be generated according to the change.

The main control unit 300 analyzes in real time the components and concentrations of ions or radicals inside the reaction chamber based on the signal received from the optical sensor module 230, and compares the analyzed data with a reference value to the reaction chamber 100. It monitors the presence or absence of abnormalities in the plasma process in progress. The main control unit 300 processes a signal transmitted from the optical sensor module 230 to control the operation of the plasma reaction chamber 100 or output a signal indicating the state of the reaction chamber 100 to the real-time display unit 360 do.

The presence or absence of plasma is linked to the equipment and receives the plasma-on (RF ON) signal, or if it is not linked with the equipment as an alternative, the standard signal (DNA) of the process is input, so the sensor value when plasma is present. And, it can be detected by comparing the sensor value when there is no plasma.

The main control unit 300 is an equipment that transmits and receives electrical signals to and from the optical sensor module 230, stores received information, analyzes it, and controls the optical sensor module 230, and includes a computer, a microprocessor, a signal processor, or other information. A processing terminal device may be used, and a display device may be included. To this end, an application may be mounted and executed in the main control unit 300. The main control unit 300 can receive electrical signals through wired and wireless communication with the optical sensor module 230, and can store and calculate the received electrical signal and transmit the result value to the optical sensor module 230 for control. I can.

The main control unit 300 includes an A/D converter 331 for converting a light sensing signal generated from the optical sensor module 230 into a digital signal; A color analysis unit 336 for converting the light detection signal converted into a digital signal into numerically quantified RGB optical data; A comparison unit 337 for comparing the RGB optical data transmitted from the color analysis unit 336 with the previously stored RGB optical data; And a data storage unit 335 for storing step-by-step reference data and process allowable range data of the plasma process. The data storage unit 335 stores data sensed by the optical sensor module 230, reference data, and optical data within a process allowable range. The data storage unit 335 may be an immutable data storage device such as a floppy disk drive or a fixed disk drive, which may be local or remote.

The main control unit 300 may, in some implementations, be integrated into, coupled to, or otherwise networked to, a computer coupled to, or part of a computer in some implementations. For example, the main control unit 300 may be in the "cloud" or may be part or all of a fab host computer system, which may enable remote access for wafer processing.

The main control unit 300 may include a real-time display unit 360 provided to allow a user to immediately check the state of the process chamber by displaying process parameter related data inside the process chamber on a screen. The real-time display unit 360 enables the display of process parameter related data inside the plasma processing chamber in real time on a screen according to a signal transmitted from the main control unit 300. The real-time display unit 360 may be a display device 361 such as an LCD display device, a touch panel, and a touch screen. The real-time display unit 360 may include a key input device 362 or a communication port 363. The real-time display unit 360 may be configured to display user interfaces described herein.

Information displayed externally through the real-time display unit 360 includes the elapsed time and progress of the process, the process input parameters and actual process variables of the reaction chamber 100, real-time RGB color and N-CH color optical data acquired from the plasma, and Information such as the RGB color of the process allowable range and the N-CH optical data space may be included, but is not limited thereto. The display unit 361 of the real-time display unit 360 may function as an input unit such as a touch pad, and through this, it is possible to input not only a sensor option value, but also a recipe input, a step setting, and an emission brightness value input.

The main control unit 300 may transmit and receive electrical signals through wired/wireless communication with the optical sensor module 230, store and calculate the received electrical signal, and transmit the result value to the optical sensor module 230 for control. .

The main processor 340 includes the process input parameters of the reaction chamber and the actually measured process variables (gas pressure, gas flow rate, applied power), RGB optical data and N-CH optical data transmitted from the color analysis unit 336. A signal for determining whether the plasma transmitted is normal or not is input from the and comparison unit 337, and transfers the process input parameter and actual process variable values, and RGB and N-CH optical data to the real-time display unit 360.

Here, when the plasma state is normal, the main processor 340 additionally transmits a signal indicating that the plasma state is normal to the state diagnosis unit 370. However, when the plasma state is abnormal, the main processor 340 transmits a warning generation signal to the warning unit 380 and additionally transmits a signal indicating that the plasma state is abnormal to the state diagnosis unit 370.

The plasma process monitoring apparatus of the present invention may include a process information external input unit 390 that receives information about a plasma process recipe from the apparatus when the plasma process monitoring apparatus is interlocked with the plasma process apparatus. The process information external input unit 390 may communicate with the input/output board 350.

Preferably, the plasma process monitoring apparatus of the present invention may include a processing method of generating a control signal for changing the state of plasma to a normal state and transmitting it to the reaction chamber 100, thereby reducing the defective rate of the plasma process. I can. Here, the control signal may include a signal for changing the amount and pressure of the reaction gas, the processing time, the strength of the applied power, and whether the main control unit 300 of the reaction chamber 100 is operated.

The A/D converter 331 may convert the light quantity measured by the color sensor 231 into an analog-to-digital conversion and output it. That is, an individual A/D converter 331 may be provided for each RGB color and N-CH color channel, or a plurality of A/D converters 331 may parallel the entire RGB color signal and N-CH color signal. It can be prepared in a way that is connected and processed. A/D converter 331 may be provided in plural in order to quickly convert analog RGB color signals and N-CH color signals in real time.

In addition, when the RGB color signal and the N-CH color signal generated by the optical sensor module 230 through the A/D converter 331 are converted into digital signals, 0 to 255 per each RGB color and N-CH color channel In addition to the conventional 8-bit RGB color signal and N-CH color signal system with color expression levels between, more extended 10-bit (0-1023), 12-bit (0-4095), or 14-bit (0-8195) ), 16 bits (0 to 65535), 20 bits (0 to 1048575), or 24 bits (0 to 16777215) system, through which it is possible to express minute changes in the signal, but is not limited thereto. .

The color analysis unit 336 maps the digital RGB color and N-CH color signals transmitted from the A/D converter 331 to R channel data, G channel data, B channel data, and N-channel data to 3D coordinates ( mapping) to generate basic RGB color and reference value-CH color optical data used in the comparison unit 337 to be described later. That is, the digital RGB color signal and the reference value-CH color signal transmitted from the A/D converter 331 are separated for each channel (R channel data, G channel data, B channel data, reference value channel data) and recombined into a data bundle. Is done.

Alternatively, the color analysis unit 336 converts the separated digital data for each RGB color and reference value-CH color channel into hue (H: Hue), saturation (S: Saturation), and brightness (B: Brightness), It can also be provided in a way that is tied in dimensional coordinates. Here, the hue has a value of 0 to 360, and the maximum size of saturation and brightness is provided according to the number of bits determined by the A/D converter 310.

Preferably, process progress time data may be included in the 3D data bundle, and since the process progress time data is included together, the state of plasma according to the process progress can be traced, through which the precision of the plasma process Can increase.

The comparison unit 336 includes real-time RGB optical data ((R, G, B) or (H, S, B) coordinate data) transmitted from the color analysis unit 337 and stored in the data storage unit 335. It is a component for comparing RGB optical data acquired from plasma in a normal state.

Meanwhile, the comparison unit 337 includes the R-channel data, G-channel data, and B-channel data (or H data, S data, and B data) of the RGB and N-CH optical data values measured in real time. G, B (or H, S, B) data and the same type are compared and judged, and when any one of the optical data values is out of the normal range, a signal that determines that the current plasma state is abnormal is generated. . Here, the RGB optical data of the process allowable range as a criterion for determination may be obtained from past normal process data or pilot process data before the present process. RGB optical data in the process allowable range, which is a criterion for determining whether the plasma process is normal, is stored in the data storage unit 335.

8 is a graph showing three-dimensional coordinates of the RGB and N-CH optical data space of the plasma process allowable range. Referring to FIG. 8(a), when the RGB and N-CH optical data values measured in real time are included in the RGB and N-CH optical data space within the process allowable range (A), the current plasma state is in a normal state. Is judged to be. On the other hand, if the RGB and N-CH optical data values measured in real time are not included in the RGB and N-CH optical data space within the process allowable range (B), it is determined that the current plasma state is abnormal. This applies equally to the case where RGB optical data is provided as HSB coordinate data, and as shown in FIG. 8(b), the color, saturation, and brightness transmitted from the color analysis unit 336 in the comparison unit 337 When comparing the data and the color (H), saturation (S), and brightness (B) data of the process allowable range by the same type, if any of the data is out of the process allowable range, the plasma in the process chamber is in an abnormal state (D ), and if the HSB optical data values measured in real time are included in the HSB optical data space within the process allowable range (C), it is determined that the current plasma state is in a normal state. At this time, even if the same state is displayed, since the coordinate values expressed in RGB and the coordinate values expressed in HSB are different from each other, the shape of the process allowable range has a different shape depending on which coordinate axis is expressed.

For example, if the R channel data in the process allowable range is 20 to 37, G channel data is 33 to 50, and B channel data is 79 to 81, the RGB and N-CH optical data values measured in real time are (21, 42, 80), it is determined that the current plasma state is normal. However, when the RGB and N-CH optical data values measured in real time are outside the process allowable range, such as (19, 35, 81), the current plasma state is determined to be abnormal.

Since the state of the plasma changes according to the progress of the plasma process in the reaction chamber, the RGB and N-CH optical data in the process allowable range for each process step changes with the passage of time, which is the three-dimensional shape of FIG. It can be expressed in a form in which the size and location change according to.

The self-step recognition unit 332 determines which stage of the entire recipe corresponds to the current region based on the value obtained from the comparison unit 337. The self-stage recognition unit 332 calculates and provides an amplification time constant value for controlling the automatic gain adjustment amplifier 233 of the optical sensor module 230.

A plasma process monitoring apparatus according to an embodiment of the present invention may include an optical sensor module 230 and a power supply unit 310 supplying power to the main control unit 300. The power supply unit 310 is driven by supplying power to the optical sensor module 230 and the main control unit 300, and specifically, can supply sufficient DC power to operate the optical sensor module 230 and the main control unit 300. . In one embodiment, the main control unit 300 and the power supply unit 310 are separated, but depending on the embodiment, the main control unit 300 and the power supply unit 310 may be integrally formed.

The plasma process monitoring apparatus according to an embodiment of the present invention inputs and outputs an electric signal transmitted between a separate PC 500 controlling a plasma process outside the plasma process monitoring apparatus and the main control unit 300 of the plasma process monitoring apparatus. An input/output board 350, which is a wired/wireless communication port, may be additionally included.

The plasma process monitoring apparatus of the present invention may further include a warning unit 380 that generates a warning sound or a warning light according to a signal transmitted from the main processor 340. The warning unit 380 is a component that turns on the warning siren and the warning lamp according to the warning generation signal of the main processor 340 when the plasma state is abnormal. The warning unit 380 is installed outside of the reaction chamber 100 or in a control facility and space that oversees the entire process, and immediately informs the user of an abnormality in the plasma process.

On the other hand, when the optical sensor module 230 is installed in the main control unit 300, as shown in Figs. 5 and 6, the optical sensor module 230 is integrated in the main control unit 300 It can be composed of. That is, the optical sensor module 230 according to the present invention is provided in the above-described configuration and is installed outside the reaction chamber 100 and connected to the main control unit 300 or the optical sensor module 230 is the main control unit 300 (Eg, one master board) may be installed in a built-in structure to be formed integrally.

7 is a schematic block diagram of a plasma process monitoring apparatus according to another embodiment of the present invention. The plasma process monitoring apparatus of the above embodiment includes a system-on-chip (SoC), and the optical sensor module 230, the main control unit 300, and the light source unit 400 may be configured as a system-on-chip. . The plasma process monitoring apparatus of this embodiment can be miniaturized and can be installed regardless of the installation environment.

Next, the operation of the plasma process monitoring apparatus described above will be described. A stage 110 to which a semiconductor wafer W is fixed is provided in the reaction chamber 100, and when the semiconductor wafer W is fixed to the stage 110, the reaction gas is supplied through the process gas injection unit 130. Is injected. Thereafter, when power is applied to the inside of the reaction chamber 100 by the RF power supply unit 120, the reaction gas applied to the inside of the reaction chamber is changed to a plasma state, and the semiconductor wafer undergoes photographic and deposition processing in other unit processes. Dry etching or deposition process for (W) is performed.

When plasma is formed in the reaction chamber 100 and light is emitted through the viewport 140 of the reaction chamber 100, the light is transmitted to the color sensor 231 of the optical sensor module 230 through a lens unit (not shown). Condensed. The lens unit may be disposed at the front end of the optical sensor module 230 so as to collect the emitted light of the plasma. The collected light is transmitted to the color sensor 231 to measure the state of plasma according to the plasma process. The optical sensor module 230 individually receives red, green, blue, and light according to each process from the light generated from the plasma gas in the reaction chamber by the color sensor, and automatically acquires the signal obtained from the color sensor 241. Amplification is performed through an adjustable amplifier 233. At this time, amplification is performed using the amplification time constant supplied from the self-stage recognition unit 332 of the main control unit 300. The optical sensor module 230 outputs an amplified electric signal corresponding to the measured value of the amount of light of the plasma emitted light to the A/D converter 331, and the A/D converter 331 is a main control unit 300 through the communication unit 338. ).

The main control unit 300 numerically quantifies the current plasma state inside the process chamber by individually analyzing the RGB color signal and the N-CH color signal converted to a digital signal, and the signal transmitted from the color analysis unit 336 and The RGB and N-CH color signal values obtained from the steady state plasma are compared. The main control unit 300 generates a control signal for controlling the operation of the process chamber by combining the data transmitted from the optical sensor module 230 and the signal transmitted from the comparison unit, or a signal indicating the state of the process chamber Transmit.

The self-stage recognition unit 332 controls the amplification time constant value of the automatic gain adjustment amplifier 233 for each pre-inputted recipe, and uses its own step recognition program for recipes that are not input. Controls the amplification time constant value of the automatic gain adjustment amplifier 233.

As described above, the plasma process monitoring apparatus according to the present invention immediately detects minute process changes in the chamber for all stages, even when the difference in plasma flux for each stage is large in a plasma process in which several stages in the same recipe exist. It can detect, and in real time, it is possible to detect an abnormal state of the plasma in the reaction chamber. Accordingly, it is possible to immediately detect a minute change in state inside the reaction chamber in real time, thereby reducing the defect rate of the wafer etching process due to abnormal plasma conditions, and enabling more detailed and accurate plasma process monitoring.

Next, a plasma process monitoring method according to an embodiment of the present invention will be described. In monitoring the plasma process in the plasma process monitoring apparatus of the present invention described above, the main control unit 300 determines whether there is plasma in the corresponding region, and when it is determined that the corresponding region does not have plasma, the light source unit in the reaction chamber By irradiating the monitoring light, the difference in the concentration of specific ions or radicals in the reaction chamber is measured. It determines which stage of the entire plasma process recipe the current area corresponds to, controls the automatic gain adjustment amplifier to adjust the amplification time constant in the optical sensor module according to the corresponding stage, and amplifies the measured value from the optical sensor module. At this time, the measured value of the step is amplified using the amplification time constant suitable for each process step supplied from the self-step recognition unit.

In the method of the present invention, the light-sensing data measured by the optical sensor module is divided into R channel data, G channel data, and B channel data, respectively, and then quantified, and then R channel data, G channel data and B channel measured in real time. If any of the data is out of the process allowable range, it is determined that the plasma in the reaction chamber has reached an abnormal state.

The method compares the measured hue, saturation, and brightness data with the hue, saturation, and brightness data within the process allowable range, and if any one of the data is out of the process allowable range, the plasma in the reaction chamber is in an abnormal state. It includes determining that it is early.

In the method of the present invention, the step of measuring a change amount of RGB optical data according to a process input parameter, comprising the steps of individually measuring the change amount of R channel data, G channel data, and B channel data; Calculating and storing a reference value from RGB optical data; And calculating a process allowable range based on the reference value.

When it is determined that the RGB optical data value obtained during the plasma process is out of the process allowable range in the method of the present invention, a warning signal for driving the warning unit may be generated.

One or more embodiments of the present invention may also be fabricated in computer-readable code on a computer-readable medium. A computer-readable medium is any data storage device capable of storing data that can be later read by a computer system. Examples of computer-readable media are hard drives, network attached storage (NAS), ROM, RAM, compact disc-ROM (CDROMs), CD-Rs (CD-recordable), CD-RWs (CD-rewritable). , Magnetic tape and other optical and non-optical data storage devices. Computer-readable media may include computer-readable tangible media distributed through a network-coupled computer system such that computer-readable code is stored and executed in a distributed manner.

Although the method operations have been described above in a specific order, other housekeeping operations may be performed between operations, operations may be adjusted so that operations occur at slightly different times, or operations may be in the direction in which the processing of the overlay operation is desired. It should be understood that it may be distributed in a system that allows processing operations to occur at various intervals associated with processing as long as they are performed.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be interpreted as being included in the scope of the present invention.

100: reaction chamber 140: viewport
200: optical sensor module
231: color sensor 233: automatic gain adjustment amplifier
241: N-CH color sensor 243: N-CH automatic gain adjustment amplifier
300: main fisherman 331: A/D converter
336: color analysis unit 332: self-level recognition unit
337: comparison unit 340: main processor
380: warning unit 360: real-time display unit
390: process information external input unit 400: light source unit

Claims (15)

An optical sensor module installed in the reaction chamber of the plasma process to detect light emitted from the light source unit;
A light source unit for irradiating monitoring light into the reaction chamber according to the control of the main control unit; And
And a main control unit for controlling the operation of the plasma reaction chamber by analyzing the measurement result of the optical sensor module,
The optical sensor module detects the light emitted from the light source and uses a color sensor that detects a difference between specific ions or radicals due to the light irradiated by the light source and an amplification time constant for each step received from the self-step recognition unit. Including an optical sensor module consisting of an automatic gain adjustment amplifier that amplifies the signal from the color sensor and adjusts the amplification gain according to each process step,
Wherein the main control unit includes a self-step recognition unit that determines which stage of the entire plasma process recipe corresponds to the current region, calculates an amplification time constant suitable for the corresponding stage, and provides it to the automatic gain adjustment amplifier. Monitoring device.
The apparatus of claim 1, wherein the automatic gain adjustment amplifier is a programmable gain amplifier (PGA) or a voltage gain adjustment circuit (VGA).
The method of claim 1, wherein the self-step recognition unit stores standard (DNA) data in a normal state, so in the etching and deposition process, the data in the current working state and the standard (DNA) data in the normal state are compared and allowed. Plasma process monitoring apparatus, characterized in that configured to generate an alarm when out of the error range.
The method of claim 1, wherein the color sensor includes an optical sensor module including a plurality of RGB sensors including an R channel sensor, a G channel sensor, and a B channel sensor, or a single element, and at this time, 150 nm~ The plasma process monitoring apparatus, characterized in that it is configured to be expandable from 2 to N channels at a wavelength within a range of 1500 nm, and wherein the color sensor is a photodiode, a phototransistor, or a photo vacuum tube type.
The method of claim 1, wherein the main control unit,
A/D converter for converting the light sensing signal generated from the optical sensor module into a digital signal; A color analysis unit for converting the light sensing signal converted into a digital signal into numerically quantified RGB optical data; A comparison unit comparing the RGB optical data transmitted from the color analysis unit with the RGB optical data in a normal state; And a data storage unit for storing step-by-step reference data and process allowable range data of the plasma process.
The plasma process monitoring apparatus of claim 5, wherein the main control unit further comprises a real-time display unit for displaying process parameter related data inside the reaction chamber under the control of the main control unit.
The apparatus according to claim 5, wherein, in the color analysis unit of the main control unit, the size of the light detection signal measured from the optical sensor module is divided into R channel data, G channel data, and B channel data to be digitized, and the comparison unit In the R, G, B channel data transmitted from the color analysis unit and the R channel, G channel, and B channel data of the process allowable range are compared for each same channel, when comparing the data, any one of each channel data is processed. When out of the allowable range, plasma process monitoring apparatus, characterized in that it is configured to determine that the plasma in the reaction chamber has reached an abnormal state.
The plasma process monitoring apparatus according to claim 3, wherein the apparatus further comprises a warning unit for generating a warning sound or a warning lamp according to a signal transmitted from the main control unit.
The color analysis unit according to claim 5, wherein the size of the RGB signal measured from the optical sensor module is divided into R-channel data, G-channel data, and B-channel data, and then quantifies the color data through a combination of each data. Data, saturation data, and brightness data are converted, and the color, saturation, and brightness data transmitted from the color analysis unit in the comparison unit are compared with the color, saturation, and brightness data in the process allowable range by the same type. When any one of the data is out of the process tolerance range, it is determined that the plasma in the reaction chamber has reached an abnormal state.
In the plasma process monitoring apparatus of claim 1, a method for monitoring a plasma process, the method
Determining whether plasma is present in the corresponding region by the main control unit;
If it is determined that the region does not contain plasma, measuring a concentration of a specific ion or radical in the reaction chamber by irradiating monitoring light in the reaction chamber by a light source unit;
Determining which stage of the entire plasma process recipe corresponds to the current region and controlling the automatic gain adjustment amplifier to adjust the amplification time constant in the optical sensor module according to the corresponding stage; And
When amplifying the measured value from the optical sensor module, a plasma process monitoring method comprising the step of amplifying the measured value of the corresponding step using an amplification time constant suitable for each process step supplied from the self-step recognition unit .
The method of claim 10, wherein the method
After dividing the measured light-sensing data into R-channel data, G-channel data, and B-channel data, respectively, and quantifying them, any one of the R-channel data, G-channel data, and B-channel data measured in real time is out of the process allowable range. If so, the plasma process monitoring method comprising the step of determining that the plasma in the reaction chamber has reached an abnormal state.
The method of claim 10, wherein the method
The measured hue, saturation, and brightness data are compared with the hue, saturation, and brightness data within the process allowable range, and if any of the data is out of the process allowable range, it is determined that the plasma in the reaction chamber has reached an abnormal state. Plasma process monitoring method comprising the step of.
The method of claim 10, wherein the method
A step of measuring a change amount of RGB optical data according to a process input parameter, the step of individually measuring a change amount of R channel data, G channel data, and B channel data;
Calculating and storing a reference value from RGB optical data; And
The plasma process monitoring method, further comprising the step of calculating a process allowable range based on the reference value.
14. The plasma process monitoring method of claim 13, further comprising generating a warning signal when it is determined that the RGB optical data value obtained during the plasma process is out of the process allowable range.
The method of claim 10, wherein the method is provided in a form in which the light-emitting part and the light-receiving part are separated in a plasma-free area and face each other in a straight line to read the amount of light incident on the light-receiving part through the reaction chamber from the light-receiver And measuring the amount of light output from the light source unit by reading the amount of light reflected from the reaction chamber and the light receiving unit in one module.

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