TWI436406B - Method of wafer level transient sensing, threshold comparison and arc flag generation/deactivation - Google Patents

Description

Method for instantaneous sensing of wafer layer, comparison of enthalpy value and generation/cancellation of arc flag

This invention relates to plasma reactors for processing semiconductor workpieces, and to arc detection in such a reactor.

During semiconductor workpiece or wafer processing, the arc generated in the plasma reactor can cause damage to the workpiece or render it unusable or adversely affect the reactor chamber. Therefore, arc detection is detected to prevent the plasma reactor from processing other wafer systems necessary to avoid damage to a series of wafers. In a physical vapor deposition (PVD) plasma reactor, the arc detection is directed to detecting an arc at the sputtering target at the top of the reactor. Such arc detection is accomplished by monitoring the output of a high voltage D.C. power supply coupled to the top of the reactor to sputter the target. Instantaneous voltage or current can react to arcing. This method of detection provides a reliable means of clearly indicating the arcing at or near the sputter target at the top of the reactor. However, this type of detection does not reliably detect arcing at the wafer (wafer level). Arc). Detecting wafer-level arcing can be particularly difficult because of the RF noise caused by the RF power supplied to the wafer support pedestal around the wafer, and in some reactors, RF noise is also present. It may be caused by the RF power supplied to the conductive coils on the side walls of the chamber. Another challenge is the wide range of dynamic changes in the instantaneous voltage or current or noise system, which is caused, for example, by the RF generator conversions required for a program solution. This transient due to switching is now necessary for transients caused by wafer level arcing. A difference.

Typically, components in the reactor chamber of a plasma reactor can be damaged or degraded by contact with the plasma. In a PVD reactor, the consumables that may be damaged may include a sputter target at the top of the reactor, an internal sidewall coil, and a program ring kit surrounding the wafer support pedestal, the kit including an electrostatic chuck (electrostatic chuck) , ESC). These consumables become more susceptible to arcing when such consumables are degraded or physically altered. Therefore, how to determine when to replace the consumables to complete the replacement before the arc phenomenon occurs is a problem to be solved.

The present invention provides a method for processing a semiconductor wafer in a type of plasma reactor comprising an RF or electrical power generator and an electrostatic chuck having at least one sink electrode. The method includes: sensing an instantaneous voltage or current on a conductor coupled to the wafer, and providing a first comparator for performing the sensed instantaneous voltage or current with a threshold value stored in the comparator Comparison. The method further includes: transmitting an arc flag signal output by the comparator whenever the sensed instantaneous voltage or current exceeds the threshold value, and returning the arc flag signal to turn off the power generator.

Figure 1A illustrates a PVD reactor having a system for effectively sensing wafer level arcing. The reactor includes a chamber 100 that is A cylindrical sidewall 102 defines a reactor top 104 and a bottom 106. A target 110 is provided inside the chamber 100 at the top 104; an RF coil 112 is placed at the sidewall 102; and a wafer support pedestal 114 extends upwardly from the bottom 106. A vacuum exhaust pump 116 evacuates the chamber 100 through an exhaust pump 埠 118 at the bottom 106. A program gas supply 119 that supplies a process gas and introduces the gas into the chamber 100.

In one embodiment, the wafer support pedestal 114 can include an electrostatic chuck (ESC) 122 for supporting the semiconductor wafer or workpiece 120 on the upper surface of the pedestal 114. The ESC 122 can include an insulating layer 124 on a conductive mount 126. In the embodiment shown in FIG. 1A, the ESC 122 is a bipolar holder having two electrodes 128, 130 in the insulating layer 124 and a conductive center pin 132 that contacts the back side of the wafer 120. A sink voltage supply 134 provides a D.C. voltage that is inverted but of the same size between the center pin 132 and the electrodes 128, 130. FIG. 1B illustrates a specific embodiment, which is a variation of the embodiment of FIG. 1A, wherein the ESC 122 is a monopolar chuck having a single electrode 128, the diameter of which is generally equivalent to a workpiece or wafer 120. The diameter. In the particular embodiment of Figure 1B, the center pin 132 may not be present. In addition to these differences, the embodiments of Figures 1A and 1B contain the same structural features, and the description of these same features with reference to Figure 1A below can also be used to illustrate the embodiment of Figure 1B, and therefore will not be heavy for the sake of brevity. Overwrite instructions.

Referring again to FIG. 1A, the D.C. power system is supplied to the sputter target 110 by a high voltage D.C. power generator 136. The low frequency RF power is provided by an RF power generator 140 to the coil 112 via an RF matching impedance 138. RF Power generator 140 is coupled to one of the RF inputs of matched impedance 138. In one embodiment, the RF matching impedance 138 may have a low power D.C. input (not shown) in addition to the RF input. In the embodiment of FIG. 1A, RF bias power having a suitable frequency (eg, low frequency and/or high frequency) is provided by an RF power generator through a bias matching impedance 142 and blocking capacitors 144, 146. ESC electrodes 128, 130. An RF blocking filter 150 is coupled between the ESC electrode, the center pins 128, 130, 132 and the D.C. sink voltage supply 134, which blocks the sink voltage supply 134 from the RF power. In the specific embodiment of FIG. 1B, RF bias power having a suitable frequency (eg, low frequency and/or high frequency) is provided by RF bias power generator 148 through bias matching impedance 142 and blocking capacitor 144. To a single ESC electrode 128.

Referring again to Figure 1A, a reactor controller 152 is used to control the operation of all of the active components in the reactor. Specifically, FIG. 1A shows that the ON/OFF command is transmitted from the controller 152 to each of the power generators 136, 140, and 148, to the gas supplier 119, to the vacuum exhaust pump 116, and to the ESC suction. Seat voltage supply 134. Although not shown in the diagram of FIG. 1A, other active components in the reactor are likewise controlled by controller 152, which includes, for example, a coolant pump, a lid interlock, a lift pin actuator, A pedestal lift actuator, a gas valve opening, a wafer processing robot, and the like.

Wafer level arc detection:

It is difficult to detect the plasma arc at the wafer because of the presence of RF. Noise and harmonics, as well as large variations in instantaneous voltage or current due to non-arc phenomena (power generator switching) and arcing. This problem can be solved by detecting a change in current or voltage at the RF bias power input of the ESC 122. An RF sensor 154 is disposed (or connected) to an RF conductor 155 (eg, an inner conductor of a 50 ohm coaxial cable), and the RF sensor 154 is coupled to the RF bias generator 148 and RF bias. The impedance 142 operates. In one embodiment, RF sensor 154 is included within matching impedance 142 and is disposed at an internal coaxial output connector (not shown) that connects coaxial cable 155. The RF sensor 154 is capable of detecting an RF current or an RF voltage and generating a voltage signal that is proportional to the detected current (or the detected voltage). The voltage signal is processed by a signal conditioner 156 to generate an output signal that is filtered and peak detected and scaled to fit a predetermined range. An arc detection comparator 158 compares the magnitude of the output signal to a predetermined threshold. If the output signal size exceeds the threshold value, the arc detection comparator will output an arc flag to the reactor controller 152. Reactor controller 152 turns off active components in the reactor, such as power generators 136, 140, and 148, in response to this arc flag.

Referring now to Figure 2, the sensor 154 can be an RF current sensor. In this particular embodiment, sensor 154 includes a ferrous salt ring 160 that surrounds RF conductor 155; and a conductive (eg, copper) coil 162 that surrounds a portion of the ferrous salt ring 160. One end 162a of coil 162 can be electrically floating while the other end 162b is the output terminal of sensor 154. One of the advantages of the ferrous salt ring 160 and the coil 162 structure is that the current through the coil 162 It is weakly coupled to the RF current through the RF power type conductor 155. Therefore, the induced voltage generated by the coil 162 is attenuated, and the instantaneous change or peak value of the current through the conductor 155 is limited to a small dynamic range. There is a related characteristic that the weak coupling limits the amount of power or current that the sensor 154 can draw from the RF power of the conductor 155. Therefore, the loading effect of the sensor 154 on the RF current of the conductor 155 is negligible.

Figure 3 illustrates the different modes of operation of the signal conditioner 156. The signal conditioner 156 includes a peak detector 164; an RF filter 166 for removing noise and providing a clean signal; a size adjustment circuit 168 for providing a predetermined range; and a high impedance converter 170 for To control the signal size range, a high impedance isolation is provided between the output of the signal conditioner 156 and the sensor 154. A specific embodiment of the signal conditioner 156 is shown in FIG. In the specific embodiment of FIG. 2, peak detector 164 includes a diode rectifier 164a and a capacitor 164b in the drawing. In another embodiment, the peak detector can include other circuit components to provide an output level indicative of a true peak. The RF filter 166 is shown in the drawing as a π-network comprising a pair of shunt capacitors 166a, 166b and a series inductor 166c. The size adjustment circuit 168 is shown in FIG. 2 as a voltage divider comprising a pair of resistors 168a, 168b whose output voltage is adjusted by the ratio of the resistance of the resistor 168a to the sum of the resistance values of the resistors 168a and 168b. Zoom out. Converter 170 is shown in FIG. 2 to include an operational amplifier 171 that provides an output signal within a range that is determined by the gain of the amplifier (e.g., 0-10V). The gain can be determined by a variable feedback resistor 172 coupled to the input and output of the amplifier. Amplifier 171 For a high input impedance, it isolates the signal conditioner 156 from the load at the output of the signal conditioner.

FIG. 4 illustrates an embodiment of the sensor 154 for detecting the RF voltage on the RF conductor 155. The sensor 154 includes a resistor separation circuit 154a, 154b that is directly connected between the conductor 155 and the ground potential. The series resistance of the resistor separation circuits 154a, 154b is relatively high (million ohms). This avoids high power conversion to ground. Resistor 154a is 10-100 times smaller than resistor 154b such that the voltage detected by peak detector 164 is very small relative to the voltage across RF conductor 155. It provides a high input impedance to the sensor 154, thereby avoiding drawing a large current from the RF conductor 155. The signal conditioner 156 described above with reference to FIGS. 2 and 3 can also be used to adjust the output signal of the RF voltage sensor 154 of FIG.

FIG. 5A illustrates a variation of the embodiment of FIG. 1A in which arc detection is performed on ESC electrodes 128, 130. The RF bias power generator 148 and the RF bias matching impedance 142 of FIG. 1A are not shown in the legend of FIG. 5A. However, when RF bias power is supplied to the ESC electrodes 128, 130, RF bias power is required. Generator 148 and RF bias match impedance 142. Alternatively, RF bias power is not provided to the ESC electrodes 128, 130. The sensor 154 of Figure 1A is replaced by a voltage sensor 174 in Figure 5A. Voltage sensor 174 is connected across ESC center pin 132 (which connects the semiconductor workpiece or wafer 120) and a reference point. The reference point can be a ground point or one of the ESC electrodes 128 or 130. The voltage sensor 174 is a differential amplifier, and the two input ends thereof are respectively connected to the center pin 132 and the reference point. (for example, grounding point). The instantaneous voltage on the wafer 120 appears to form a large differential signal between the two inputs of the differential amplifier 174. The output signal of the amplifier is proportional to the differential signal and the output signal is provided to the signal conditioner 156. The output signal of the signal conditioner 156 is tested by the arc detection comparator 158 to compare the output signal with a predetermined threshold value, as in the specific embodiment of FIG. 1A.

Figure 5B illustrates a similar variant for Figure 1B, in which sensor 154 of Figure 1B is replaced by differential amplifier 174 in Figure 5. In the embodiment of Figure 5B, the two input terminals of the differential amplifier 174 are coupled to a single ESC electrode 128 and an appropriate reference voltage (e.g., a ground point). The RF bias power generator 148 and the RF bias matching impedance 142 of FIG. 1B are not shown in the legend of FIG. 5B, but when the RF bias power is supplied to the ESC electrode 128, an RF bias power generator is required. 148 and RF bias match impedance 142. Alternatively, no RF bias power is provided to the ESC electrode 128. The instantaneous voltage on the voltage wafer 120 appears to form a large differential signal between the two inputs of the differential amplifier 174. The output signal of the amplifier is proportional to the differential signal and the output signal is provided to the signal conditioner 156. The output signal of the signal conditioner 156 is tested by the arc detection comparator 158 to compare the output signal with a predetermined threshold value, as in the specific embodiment of FIG. 1A.

FIG. 6A illustrates a variation of the embodiment of FIG. 5A in which current sensor 176 replaces voltage sensor 174. Current sensor 176 includes a ferrous salt ring 178 surrounding central conductor 132 and a conductive coil 180 surrounding the ring 178. One end 180a of coil 180 is the output of current sensor 176 and is coupled to the input of signal conditioner 156. FIG. 6B illustrates a variation of a particular embodiment for FIG. 5B in which current sensor 176 ' replaces voltage sensor 174. Current sensor 176 ' includes a ferrous salt ring 178 ' that surrounds a conductor connected to a single ESC electrode 128; and a conductive coil 180 ' that surrounds the ring 178 ' . One end 180a ' of coil 180 ' is the output of current sensor 176 ' and is coupled to the output of signal conditioner 156.

Referring again to FIG. 1A, a second RF sensor 184 is coupled to an RF power type conductor 185 that is coupled between the RF generator 140 and the RF matching impedance 138 for the sidewall coil 112. The second RF sensor 184 can be an RF current sensor (as in Figure 2) or an RF voltage sensor (as in Figure 4). The output of the second RF sensor 184 is provided to a second signal conditioner 186, which may be of the same type of circuit as the signal conditioner 156 of Figures 2 and 3. A second arc detection comparator 188 compares the output signal of the signal conditioner with a particular threshold to determine if an arc is generated. If an arc is generated, comparator 188 will generate an arc flag to controller 152. A third sensor 190 is coupled to the output of the D.C. power generator 136. The output of the third sensor 190 can be provided to a third signal conditioner 192. The third arc detection comparator 194 compares the output signal of the signal conditioner 192 with a particular threshold to determine if an arc is generated. Its output an arc flag is transmitted to the program controller 152.

Controller 152 can include a memory 152a for storing a sequence of instructions and a microprocessor 152b for executing the instructions. These instructions represent A program can be downloaded to the controller memory 152a for operation of the reactor. In response to one of the characteristics, an arc flag is received in response to any of the arc detection comparators 158, 188 or 194, and the program will instruct the controller 152 to turn off the power generators 136, 140 and 148. This program will be further explained later in this manual.

Program controller operation

The operational flow description of the program controller 152 of FIG. 1A is shown in the flowcharts of FIGS. 7A and 7B, and the program scheme can be downloaded and stored in the controller memory 152a (blocks 300 of FIGS. 7A and 7B). The reactor assembly history (e.g., the number of used hours for each consumable in the reactor) can also be downloaded to controller memory 152a (block 302). The controller then initiates the in-reactor process (block 304). In the current procedural step, controller 152 performs the RF power settings required by the program (i.e., provides RF power to ESC 122 and RF power to coil 112). Based on these power settings, the controller 152 predicts the level of RF noise that each of the sensors 154, 184, and 190 will encounter. For each sensor, controller 152 determines to assign an appropriate arc detection comparison threshold to each of comparators 158, 188, and 194 based on the level of noise (block 306 of Figures 7A and 7B). For a particular sensor, an arc is considered to occur if a detected voltage (or current) level exceeds the assigned threshold. Alternatively, the controller 152 may define a warning level threshold that is lower than the arc detection threshold.

After the comparison thresholds of each of the sensors 154, 184, and 190 have been set, each threshold value depends on the relevant used hours of the consumable component of the reactor. A correction is made (block 308). The correction can be achieved based on historical data representing the general useful life of each consumable component in the reactor. For example, sensor 154 detects the arc phenomenon closest to wafer 120, at which point the state of the consumable component closest to the wafer will have the greatest impact, such as a program loop kit surrounding the ESC (not shown in FIG. 1A). Therefore, the arc detection comparison threshold of the sensor 154 is corrected according to the used hours of the program ring kit. Similarly, the sensor 184 detects an arc phenomenon at the sidewall coil 112. Therefore, the value assigned to the sensor 184 will be corrected based on, for example, the number of hours the coil 112 has been used. In general, it will be repaired as the consumables have been used, because when the consumables are worn during exposure to the plasma and the surface becomes rough, it is easy to suffer or cause more RF noise and harmonics. . Correcting the arc detection threshold based on the number of hours of use of the consumable can be achieved based on empirical data representing the history of a large number of consumable component samples.

In one embodiment, the next step will determine if the value of the upset is at or too close to the expected voltage or current level of a true arcing phenomenon (block 310). If so ("Yes" branch of block 310), a flag is output (block 311) to the user and/or to program controller 152. In a specific embodiment, this flag allows program controller 152 to shut down the reactor. In this way, it is possible to identify the position of the corresponding sensor whose 槛 value has exceeded, and to identify the reactor consumable closest to the reactor, thereby notifying the user that the consumables have been replaced for a replacement period.

If the modified threshold is not too high ("NO" branch of block 310), then the corrected thresholds are passed to arc detection comparators 158, 188 and 194 for use in the current program step (block 312). . According to the program plan, Controller 152 can identify the instantaneous current controlled by the program at a particular time (block 314), such as when starting or stopping the RF power generator. During the execution of the current program step, controller 152 monitors whether each arc detection comparator 158, 188, and 194 transmits an arc flag (block 316). In the current step, each of the comparators 158, 188, and 194 continuously compares the output signals of the signal conditioners 156, 186, and 192 with the thresholds received from the controller 152, respectively. The comparator will transmit an arc flag to controller 152 whenever the output signal value of the signal conditioner exceeds the threshold used. For example, controller 152 can sample the comparator output signal at a rate of 30 MHz. A determination is made as to whether an arc flag has been issued for each sample of comparators 158, 188, and 194 (block 318). If no flag is detected ("NO" branch of block 318), then controller 152 determines if the current program step has been completed (block 320). If the determination is not complete ("NO" branch of block 320), then controller 152 returns to the monitoring step of block 316. Otherwise, ("YES" branch of block 320) controller 152 branches to a program step (block 322) below the program protocol and returns to block 306.

If an arc flag is detected ("YES" branch of block 318), it is determined that the detected instantaneous voltage or current has only exceeded the warning level threshold or has exceeded the arc threshold level (block 324). This determination is made based on the content of the flag issued by a particular comparator. If only the warning level is exceeded ("YES" branch of block 324), controller 152 records this phenomenon and establishes a connection relationship with the current wafer (block 326). Controller 152 then determines if the number of warnings for the current wafer is too high (block 328). If the number of warnings for the wafer exceeds a predetermined number ("Yes" branch of block 328), then A flag is sent (block 330) and the controller 152 can shut down the reactor. Otherwise ("No" branch of block 328), the controller returns to the step of block 316.

If the arc flag indicates a full arc phenomenon, i.e., the arc threshold has been exceeded ("NO" branch of block 324), it is determined whether it coincides with the power conversion time identified in the step of block 314. If consistent ("YES" branch of block 332), the flag is treated as an error indication and ignored (block 334), and the controller returns to the monitoring step of block 316. Otherwise ("No" branch of block 332), the arc flag is treated as a correct message. Controller 152 uses the contents of the arc flag to identify the location of the sensor that detected the arcing phenomenon and record it in the body (block 338). The controller sends an "OFF" command to each of the power generators 136, 140, and 148 (block 340). The arc flag can include digital information to identify a particular comparator that has an arc flag sent. This information is output to the user interface by controller 152, which establishes a connection relationship between the sensor location and the consumable component (block 342). This feature allows the user to better identify the consumable components that need to be replaced in the reactor chamber. For example, if controller 152 determines that the arc flag is issued by comparator 188, it identifies the consumable component closest to the RF power monitored by the comparator, i.e., sidewall coil 112. For an arc flag transmitted by comparator 158, the closest consumable component is around those components of the wafer, particularly the program ring kit, and controller 152 will, for example, associate this arc flag with this program ring. A connection relationship is established between the suites. For an arc flag sent by comparator 194, the associated component is the top target and the controller establishes a coupling relationship between the arc flag and the top target. Thus, in a particular embodiment, the controller 152 can target Different arc flags provide a list of different possible candidate replacement consumables for the user.

The procedure of one of the embodiments illustrated in Figures 7A and 7B includes dynamically adjusting the arc detection comparison threshold in each of the plasma program steps. Depreciation is further adjusted based on the number of hours the consumable component has been used. Controller 152 can frequently update the thresholds of each of comparators 158, 188, and 194 as needed. By comparing the thresholds with such dynamic adjustments, the minimum threshold for a particular wafer program step can be sought to optimize the sensitivity of each of the comparators 158, 188, and 194. Whenever the noise condition (for example) is improved, the value can be repaired, and when, for example, the RF power level rises and the degree of noise increases, the value can be repaired. Increasing the threshold can avoid false arc indications that occur when the noise level approaches the arc detection threshold. In a specific embodiment, the procedures of Figures 7A and 7B further include the steps of performing the steps of identifying the arc position and identifying corresponding possible consumable components in the associated arcing phenomenon. Controller 152 communicates such information to the user to facilitate efficient management of consumables and more accurate selection of consumables to be replaced.

In one embodiment, the programs of Figures 7A and 7B are implemented as software instructions, and the software instructions can be downloaded to the controller memory 152a. Thus, in this particular embodiment, all smart actions are performed by controller 152, while the arc detect comparator only performs the compare function. However, in another embodiment, arc detection comparators 158, 188, and 194 can include their own internal processors and memory to allow them to perform certain functions in the procedures of Figures 7A and 7B.

Refurbishment to improve control and communication:

The procedures of Figures 7A and 7B are followed by frequent two-way communication between the controller 152 and each of the arc detection comparators 158, 188 and 194. Controller 152 periodically transmits the updated comparison threshold to a particular number of comparators 158, 188, and 194, with different values being downloaded to different comparators. Comparators 158, 188, and 194 transmit an arc flag whenever an arc is detected. The arc flag includes an identifier of an individual comparator that transmits the arc flag. The controller responds to one of the correct arc flags transmitted by any of the arc detection comparators 158, 188, and 194, and further transmits an ON/OFF command to the power generators 136, 140, and 148. The arc detection characteristics of Figure 1A (as implemented in Figures 7A and 7B) are intentionally added to the plasma reactor that has been operated in a zone. For reactors already installed in this zone, a custom communication network is installed on each reactor to meet each of the aforementioned communication requirements, which would be cost prohibitive. In order to reduce costs, communication will be carried out using the communication system already existing on the reactor. In some embodiments, an existing communication system is capable of complying with and promoting all of the communication requirements of the arc detection features of Figures 1 and 7.

In some reactors, a local area network (LAN) is provided through which the controller communicates with each of the active devices and sensors on the reactor. Fig. 8 illustrates a regional network structure of the reactor type shown in Fig. 1A. An interface device is coupled to each of the active devices controlled by controller 152. The interface device converts the received digital command into an action to turn off the active device. For example, in Figure 8, interface devices 355, 357, and 359 are coupled to power generators 136, 140, and 148, respectively. These media The face device can turn off the generators in response to the received digital commands. A local area network (LAN) 360 is provided. This area network is a multi-conductor transmission channel or cable having a plurality of I/O ports 361, 362, 363, 364, 365, 366 and 367, and which can be implemented as a multi-conductor connector. Each device communicating over regional network 360 has a memory and limited processing capabilities to allow it to store and transmit a unique address on regional network 360. Thus, each of the control interfaces 355, 357, 359 and each of the comparators 158, 188, 194 has conventional processing circuitry in response to the regional network protocol and stores its own device address. Each device 158, 188, 194, 355, 357, and 359 on the local area network only responds to the received message destined for its device address. In addition, each device attaches its own device address to its transmission data on the local area network. Each device 158, 188, 194, 355, 357 and 359 passes through its own multi-conductor cable 371, 372, 373, 374, 375, 376 and 377, respectively, at 埠361, 362, 363, 364, 365, 366 and 367 is coupled to the area network 360. Comparators 158, 188, and 194 may not be provided on the reactor disposed in the region having such a regional network. Thus, the arc detection system communication characteristics of FIG. 1A can be implemented in the reactor by identifying the remaining (unused) ports on the existing area network 360 (eg, 埠363, 365, and 366). ), and the comparators 158, 188, and 194 are connected to the above-described ports in the manner shown in FIG.

When the local area network 360 is activated, the device addresses of all devices on the local area network 360 (i.e., the comparators 158, 188, 194 and control interfaces 355, 357, 359) can be intelligently assigned by the controller 152 using conventional techniques. . In the system of Figure 8, the controller 152 transmits a message to the user, for example. In contrast to the comparator, the message has instructions to request that a particular threshold be downloaded to implement the procedures of Figures 7A and 7B. Each comparator responds to an arcing phenomenon by transmitting a message containing the address of the comparator device to controller 152 and transmitting a message indicating the occurrence of an arcing phenomenon. Controller 152 can respond to a correct arcing phenomenon by transmitting a message to each power generator control interface 355, 357, 359 that includes a command to request that the respective generator be turned off. The location of the sensor that sent the flag is estimated by the controller 152 based on the device address of the corresponding arc detection comparator. Controller 152 can provide this information to the user at user interface 153 of controller 152.

In other reactors, a local area network is not provided or available, and a custom digital input/output (DI/O) network is provided, as shown in Figure 9. In the DI/O network of Figure 9, each device communicates with the controller 152 via the device-specific transmission channel (and vice versa). The DI/O network on the existing reactors is individually communicated with the controller 152 using DI/O relays 401, 402, 404, 406, respectively, and individual security points are monitored. Specifically, for example, the DI/O relay 401 transmits a signal every time the cover 101 of the chamber 100 is turned on, and the DI/O relay 402 transmits a signal whenever the RF power cable is disconnected from the side wall coil, and the DI/O relay 404 The signal is sent whenever the RF bias power cable is disconnected, and the DI/O relay 406 sends a signal whenever the DC power cable is disconnected from the top target. The inputs A, B, D and F of the controller 152 receive the signals transmitted by these relays, as shown in the legend of Figure 9. Controller 152 transmits an ON/OFF command to each of power generators 136, 148, and 140 via dedicated transmission channels J, K, and L, as shown in FIG.

The communication characteristics of Figure 1A can be implemented in the DI/O network of Figure 9, with three additional DI/O relays that can cooperate with the arc detection comparators 158, 188 and 194. In the example shown in Figure 9, the existing DI/O relays 403, 405, and 407 are coupled to the outputs of the arc detection comparators 188, 158, and 194, respectively. Each time one of the arc detection comparators 158, 188 or 194 sends an arc flag, the DI/O relay connected to the comparator will send a signal to inform the controller 152. The controller 152 derives the identifier of the arc detection comparator that sends the arc flag based on the position of the cable or channel carrying the signal. This information can be communicated to the controller user interface 153 to manage the replacement of consumables.

Early reactors currently installed in a zone may not have a regional network or a DI/O network. In such a reactor, the arc detection system of Figure 1A can be implemented in a basic form that utilizes a 24 volt safety interrupt circuit provided in such a reactor to implement the detection system. This circuit ensures that the power generator is turned off immediately whenever the chamber cover is open or whenever the power cable connected to the chamber is interrupted. Referring to Fig. 10, power generator 136 has an interlocking device 501 having a interlocking device 502 and power generator 140 having a chaining device 503. Each power generator 136, 148, and 140 can only operate when its interlocking device continuously detects a 24 volt DC potential on a circuit conductor 504. Circuit conductor 504 connects all interlocks 501, 502, 503 in series to a 24 volt DC supply 506. The series circuit conductor 504 is disconnected by a number of simple switching relays 510, 512, 514, 516, 518, 520 and 522. Therefore, each relay itself can interrupt the generator interlocks 501, 502, A series connection between 503 and 24 volt supply 506 is used to shut down the reactor. The relay 510 opens its connection each time the chamber cover 101 is opened. The relay 512 opens its connection whenever the connection between the RF power cable and the side wall coil 112 is interrupted. Relay 516 opens its connection whenever the connection between the RF power cable and ESC 122 is interrupted. Relay 522 opens its connection whenever the connection between the RF power cable and the top target is interrupted. The chamber 100 can be automatically turned off in response to arc detection of any of the three arc detection comparators 158, 188, and 194, wherein three additional relays are connected in series along the circuit conductor 504 and can be used to separate The output signals of the comparators 158, 188 and 194 are received. Figure 10 shows that the three relays (i.e., relays 514, 518, and 520) can be coupled to the outputs of comparators 188, 158, and 194, respectively. Whenever any of the comparators 188, 158, 194 detects a voltage (or current) that exceeds its predetermined threshold, it will send an arc flag in the form of a voltage to cause the respective relays 514, 518, respectively. Or 520 opens its link. This will interrupt the 24 volt path of conductor 504, causing each interlocking device 501, 502, 503 to turn off associated power generators 136, 148, and 140, respectively.

The specific embodiment of the RF matching impedance 138 shown in FIG. 1A has a single RF input and a single RF output. However, in another embodiment, the RF matching impedance 138 may additionally have a low power DC input (not shown). In the picture). In this embodiment, one of the foregoing types of additional arc sensors and threshold comparators can be coupled to a low power D.C. input of an RF matching impedance 138, not shown.

The reactor of Figure 1A or 1B has been described above in terms of various sensors A single sensor in 154, 184, 190, etc. performs arc detection, however the determination of arc detection may also be based on several (or possibly all) of the sensors. For example, it has been explained that the controller 152 of the specific embodiment of the first, eighth or ninth embodiment transmits the response to the arc according to the output signal of any of the sensors 154, 184 or 190 through the comparators 158, 186 or 194, respectively. phenomenon. However, in one embodiment, the controller 152 of the first, eighth or ninth embodiment is programmed to combine at least two (or more) threshold comparators 158, 186 and to determine based on the combined signals. . The output signals can be combined by the processor 152 in accordance with linear, polynomial or more complex mathematical functions. In this embodiment, controller 152 is programmed to respond to the combined signals to determine if an arc is detected or to decide whether to shut down the reactor. In yet another embodiment, the individual output signals of the sensors 154, 184, 190 can be combined first and then processed by a threshold comparator. The individual output signals of at least two of the sensors 154, 184, 190 can be combined according to linear, polynomial or more complex mathematical functions. The resulting combined signal is then provided to a single comparator (e.g., comparator 186) and the output signal of the single comparator is provided to controller 152.

The foregoing description is directed to specific embodiments of the invention, and other specific embodiments of the invention may be made without departing from the basic scope of the invention. The scope of the invention is defined by the scope of the following claims.

100‧‧‧ chamber

101‧‧‧ chamber cover

102‧‧‧ side wall

104‧‧‧ top

106‧‧‧ bottom

110‧‧‧ Target

112‧‧‧RF coil

114‧‧‧Base

116‧‧‧Vacuum exhaust pump

118‧‧‧Exhaust pump埠

119‧‧‧ gas supply

120‧‧‧Workpiece

122‧‧‧Electrostatic suction seat

124‧‧‧Insulation

126‧‧‧Electrical seat

128, 130‧‧‧ electrodes

132‧‧‧conductive central pin

134‧‧‧Voltage supply

136‧‧‧D.C. Power Generator

138, 142‧‧‧ Matched impedance

140, 148‧‧‧RF power generator

144‧‧‧ Capacitance

146‧‧‧ Capacitance

150‧‧‧RF blocking filter

152‧‧‧ Controller

152a‧‧‧ memory

152b‧‧‧Microprocessor

153‧‧‧User interface

154‧‧‧RF sensor

154a, 154b‧‧‧resistance

155‧‧‧RF conductor

156‧‧‧Signal regulator

158‧‧‧Arc Comparator

160‧‧‧ ferrous salt ring

160a, 160b‧‧‧ coil end

162‧‧‧ coil

164‧‧‧peak detector

164a‧‧ Diode Rectifier

164b‧‧‧ capacitor

166‧‧‧RF filter

166a, 166b‧‧‧ capacitor

166c‧‧‧Inductance

168‧‧‧Size adjustment circuit

168a, 168b‧‧‧resistance

170‧‧‧ converter

171‧‧Amplifier

172‧‧‧Responsive resistance

174‧‧‧ voltage sensor

176, 176 ' ‧ ‧ current sensor

178, 178 ' ‧ ‧ ferrous salt ring

180,180 ' ‧‧‧ Conductive coil

180a, 180a ' ‧‧‧ coil end

184‧‧‧RF sensor

185‧‧‧RF power conductor

186‧‧‧Signal regulator

188, 194‧‧‧ arc comparator

190‧‧‧ sensor

192‧‧‧Signal regulator

355, 357, 359‧‧‧ control interface

360‧‧‧Network

361~367‧‧‧I/O埠

371~377‧‧‧Multi-conductor cable

401, 402‧‧‧DI/O relay

404, 406‧‧‧DI/O relay

501, 502, 503‧‧ ‧ interlocking devices

504‧‧‧Circuit conductor

506‧‧24 volt DC supply

510, 512, 514‧‧‧Switch relay

516, 518‧‧‧Switch relay

520, 522‧‧‧Switch relay

In the method provided by the present invention, the method embodiment can be "invention content" The description of the paragraphs is obtained and understood, and the specific description of the invention, which is summarized in the "Summary of the Invention", is described with reference to the accompanying drawings. It is to be noted, however, that the appended claims are intended to illustrate

1A and 1B illustrate a plasma reactor having bipolar and monopolar electrostatic chucks, respectively, which have specific wafer level arc detection and auto-shutdown characteristics.

Fig. 2 is a schematic view showing an RF current sensor circuit of the reactor in Fig. 1A.

Figure 3 is a block diagram illustrating the signal conditioner of the reactor of Figure 1A.

Fig. 4 is a schematic view showing an RF voltage sensor circuit of the reactor in Fig. 1A.

5A and 5B respectively illustrate a modified schematic view of a specific embodiment of FIGS. 1A and 1B, in which a wafer level arc detecting circuit is provided on the electrostatic chuck, and a voltage sensor is used.

6A and 6B respectively illustrate a modified schematic view of a specific embodiment of FIGS. 1A and 1B, in which a wafer level arc detecting circuit is provided on an electrostatic chuck, and a current sensor is used.

Figures 7A and 7B collectively establish a complete flow diagram illustrating the operational flow of the reactor controller of any of the foregoing specific embodiments.

Figure 8 illustrates the application of the arc sensing and communication characteristics refurbishment of Figure 1A to a reactor having a regional network.

Figure 9 illustrates the application of the arc sensing and communication characteristics refurbishment of Figure 1A to a reactor having a digital input/output network.

Figure 10 illustrates the application of the arc sensing and communication characteristics refurbishment of Figure 1A to a reactor having a D.C. safety interlocking loop.

In order to facilitate the understanding of the present invention, the same reference numerals are used to refer to the same elements. The drawings in the attached drawings are schematic and are not to scale.

Claims (14)

A method of detecting an arc in a plasma reactor, the plasma reactor comprising an RF or electric power generator for processing a semiconductor workpiece or wafer carried on a workpiece support base, the base having At least one electrode, the method comprising the steps of: sensing a first instantaneous voltage or current coupled to the semiconductor of the wafer; providing a first comparator for storing the instantaneous voltage or current Comparing a threshold value in the comparator; each time an instantaneous voltage or current is sensed to exceed the threshold value, transmitting an arc flag signal sent by the comparator; and echoing the arc flag signal, And turning off the power generator; downloading a program scheme, which is executed by the reactor; in each program step of the program scheme, determining a threshold value of the comparator according to the RF power level specified in each step Level, the threshold value exceeds one of the expected noise levels of the program step; at one of each program step, the comparator is replaced with one of the threshold levels determined for each current program step original Depreciation level. The method of claim 1, further comprising the step of: adjusting, according to the use history of the consumables associated with the wafer level arc in the reactor for each procedural step, adjusting the enthalpy determined in the procedural step Value level. The method of claim 2, further comprising the step of: determining whether a threshold value is equal to or exceeding an expected instantaneous voltage or current level of an arc phenomenon after adjusting the threshold value, And send this information to a user interface. The method of claim 1, further comprising the steps of: sensing a second instantaneous voltage or current associated with an RF source power generator at a selected location in the reactor; providing a second comparator, And comparing the second instantaneous voltage or current with a threshold value stored in the second comparator; transmitting the first time when one of the second instantaneous voltages or currents sensed exceeds the threshold value The second comparator sends an arc flag signal; the arc flag signal sent by the second comparator is returned, and the source power generator is turned off; and the comparator is notified to send the arc flag to the user interface. An identifier, or an identifier of a reactor consumable component associated with the comparator that sends the arc flag. The method of claim 4, further comprising the steps of: downloading a program scheme, which is executed by the reactor; and in each program step of the program scheme, for each of the comparators, According to the RF power level specified in each step, decide each One of the comparators has a threshold value that exceeds one of the expected noise levels of the program step; at one of each program step, one of the threshold values determined for each current program step The original threshold value of the comparator is replaced. The method of claim 5, further comprising the steps of: adjusting, in each of the program steps and each of the comparators, the history of the consumables associated with the comparator in the reactor, the step of adjusting the procedure is determined The threshold value. The method of claim 6, further comprising the step of: determining whether a threshold value is equal to or exceeding an expected instantaneous voltage or current level of an arc phenomenon after adjusting the threshold value, And a user interface of the identifier of the corresponding comparator or consumable. A method of monitoring an arc in a chamber of a plasma reactor, the reactor including the chamber having a plurality of plasma power applications and a plurality of power generators coupled to the power applications, and Included as a workpiece support base having a workpiece support surface, the method comprising the steps of: implementing a plasma program according to a program scheme, the program scheme comprising a series of program steps controlled by a program controller; Monitoring voltage or current to the power applications and individual sensors coupled to the workpiece support pedestals; Determining an arc detection threshold for each of the sensors in each of the procedural steps, the value of which is higher than a noise level; the individual sensor is detected by an individual arc detection comparator The output signal is compared with the threshold determined by the individual sensor, and if the output signal exceeds the threshold, an arc detection flag is sent; determining a corresponding sensing that causes an arc detection flag Position of the device and display the location on a user interface; and return the arc flag to turn off the power generator. The method of claim 8, wherein the reactor further comprises a regional network having a plurality of turns, the controller being linked to one of the plurality of devices, the generators comprising a plurality of interfaces, Linking to individual 埠 in the 埠 and identifying by individual device addresses, the method further includes the steps of: linking each of the comparators to other individual 埠 in the 埠 and assigning a unique device The address is given to each of the comparators. The method of claim 9, further comprising the step of: programming the controller to download the thresholds used in the series of program steps to the individual complex comparators of the comparators through the area network . For example, the method described in claim 10 includes the following steps: The controller is programmed to receive the arc flag sent by the comparators and to shut down the generators through the local area network. The method of claim 11, further comprising the step of: programming the controller to identify an arc based on a device address included in an arc flag received through the area network; Flag location. The method of claim 8, wherein the reactor further comprises a digital input/output (DIO) network, the network having a dedicated transmission from an individual DIO sensor relay to the controller Individual complex channels, and individual complex channels dedicated to transmission between the controller and the individual power generators of the reactor, the method further comprising the steps of: outputting the individual complex comparators of the comparators The plurality of relays are coupled to the plurality of sensor relays. The method of claim 12, further comprising the steps of: establishing a relationship between the arc flag positions and corresponding consumable components of the reactor, and identifying the consumable components of each arc flag and Provide a user interface.