CN103515181B

CN103515181B - For the method and apparatus processing substrate in the plasma process system have electrode

Info

Publication number: CN103515181B
Application number: CN201310253580.0A
Authority: CN
Inventors: 约翰·C·小瓦尔考; 布拉德福德·J·林达克
Original assignee: Lam Research Corp
Current assignee: Lam Research Corp
Priority date: 2012-06-22
Filing date: 2013-06-24
Publication date: 2016-06-08
Anticipated expiration: 2033-06-24
Also published as: KR20140000172A; TWI592978B; CN105914123B; KR102133057B1; CN105914123A; CN103515181A; TW201415519A

Abstract

The present invention relates to the method and apparatus for controlling plasma in plasma process system, specifically disclose the method and apparatus for processing substrate in multi-frequency plasma processing chamber. Base RF signal applies pulse between high power levels and low-power level. When base RF signal applies pulse, each in non-base RF generator in response to take the photograph before control signal (proactively) switching between the predefined power level of the first predefined power level and second. Alternately or in addition, when base RF signal applies pulse, each in non-base RF generator is in response to switching between the first predefined RF frequency and the second predefined RF frequency with taking the photograph before control signal. The invention discloses for determining the first and second predefined power levels and/or the technology of the first and second predefined RF frequencies before the production time for non-base RF signal.

Description

For the method and apparatus processing substrate in the plasma process system have electrode

Related application

The application claim is called " FREQUENCYENHANCEDIMPEDANCEDEPENDENTPOWERCONTROLFORMULTI-FREQUENCYRFPULSING " with the name submitted on February 22nd, 2012, attorney is P2301P/LMRX-P222P1, application number is 61/602, the commonly assigned patent application of 040 is correlated with, and it is called " METHODSANDAPPARATUSFORSYNCHRONIZINGRFPULSESINAPLASMAPROC ESSINGSYSTEM " with the name submitted on February 22nd, 2012, attorney is P2296P/LMRX-P221P1, application number is 61/602, the commonly assigned patent application of 401 is correlated with, all above-mentioned apply for reference to being incorporated herein by.

Technical field

The application relates to plasma process system, is especially for the method and apparatus controlling plasma in plasma process system.

Background technology

Cement Composite Treated by Plasma is used to process substrate (such as, wafer or flat board or other substrate) to produce electronic device (such as, integrated circuit or flat faced display) for a long time. In Cement Composite Treated by Plasma, substrate is placed in plasma processing chamber, and plasma processing chamber adopts one or more electrode to carry out excitaton source gas (it can be etchant source gas or deposition source gases) to form the plasma for processing substrate. Electrode can by RF signal excitation, and this RF signal is such as provided by RF generator.

In some plasma process systems, multiple RF signals (some of them can have identical or different RF frequency) are provided to substrate supporting electrode (herein also referred to as bottom electrode or chuck) to generate plasma, go up electrode simultaneously and are grounded. In capacitance coupling plasma process system, for instance, one or more RF signal is provided to bottom electrode, and upper electrode is grounded.

In some applications, multiple RF signal pulse can be applied. For any given RF signal, RF pulse applies to include the pulse frequency of different from RF frequency (and being generally slower than RF frequency) this RF signal to open or close (or, because pulse applies not always to need power to be closed) between high power levels and low-power level alternately.It is said that in general, RF pulse in the past applies to be performed to improve some result (such as improve uniformity or reduce the infringement that etching is relevant).

The pulse of each RF signal applies can be nonsynchronous or synchronization. For lock-out pulse is applied, for instance, if two signal RF1 and RF2 synchronize, then there is the active pulse of the signal RF1 of active pulse for each signal RF2. The pulse of two RF signals can be homophase, or the rising edge of a RF pulse can lag behind the rising edge of another RF pulse, or the trailing edge of a RF pulse can lag behind the trailing edge of another RF pulse, or RF pulse can be out-phase.

If the pulse of each RF signal applies not to be well controlled, then have following risk: can cause that in the transition process of one or more RF signal (vice versa) from low to high the RF power of plasma perturbation is unstable. This is because in such transition process of one or more RF signal, the condition of plasma in process chamber changes. Matching network and/or other RF generator that the condition of plasma that this change can be attempted to compensate for detecting changes detect. The reactive person's character (reactivenature) of this compensation means the period between condition of plasma changes detection and successfully compensates, and there is the RF power perturbation causing plasma unstable.

Fig. 1 illustrates an example of this RF power perturbation, and it can cause the plasma unstable in the transition process of one of pulsed RF signal. In the example of fig. 1,2MHzRF signal produces pulse with 100Hz with the dutycycle of 50% between 2500W and 0W. For purposes of illustration, it is assumed that 60MHzRF signal runs under continuous wave (CW) pattern, do not produce pulse. Along with 2MHzRF signal is converted to high state 104 from low state 102, changing in response to the power provided, indoor condition of plasma changes. When detecting that this condition of plasma changes, 60MHzRF signal is shown as compensating the condition of plasma change that (the compensation circuit by 60MHzRF power supply or matching network) detects.

But, this is that reactivity responds and depend on first detection 2MHz pulsed RF signal (as it was previously stated, it applies pulse with the pulse frequency of 100Hz) the condition of plasma change caused by transformation from low to high. Delay and response subsequently cause the RF power level perturbation shown in reference number 106, and reference number 106 illustrates the of short duration decline after 2MHz from low to high changes in the power level of 60MHzRF signal. After changing from the 2MHzRF of high (110) to low (112), another example of the RF power level perturbation in the 60MHzRF signal come because of the postponing response of 60MHzRF signal is illustrated by reference number 108. Other RF power perturbation is illustrated by such as reference number 114 and 116 in FIG. As shown in Figure 1, these RF power perturbations can in the positive direction or in a negative direction and can have different intensity. Plasma event that is that such perturbation causes instability and/or that be difficult to control, affects result and/or yield of devices.

Additionally, high density, high performance device manufacture in, modern plasma process impose strict result requirement. With traditional constant waveform RF signal or with traditional RF pulse applying method, it is impossible to arrive some process window or these process window are very narrow.

What the pulse of each RF signal applied handle and controls further to improve plasma stability and/or to provide extra technology controlling and process button among multiple purposes of embodiments of the present invention.

Summary of the invention

In one embodiment, the present invention relates to a kind of method for processing substrate in the plasma processing chamber have at least one electrode. Described plasma processing chamber has the multiple RF power supplys being coupled for providing multiple RF signals into described electrode. The method includes making base stage RF pulse signal apply pulse between high power levels and low-power level in the first pulse frequency, described base stage RF pulse signal represents a RF signal of the minimum pulse frequency in the pulse frequency in the plurality of RF signal with the plurality of RF signal, and described first pulse frequency is different from the RF frequency of described base stage RF pulse signal.

The method also includes the subset that control signal is at least sent to the plurality of RF power supply, wherein when processing described substrate, described control signal produces before in the way of the change of one or more room parameter that need not be next to the described applying pulse due to described base pulse signal senses with taking the photograph.

The method includes in response to described control signal, between the first predefined RF power supply certain power level and the second predefined RF power supply certain power level being different from the described first predefined RF power supply certain power level, each in the described subset of multiple described RF power supply is made to apply pulse.

Below in the specific embodiment of the present invention part, and in conjunction with accompanying drawing, these and other feature of the present invention can be described in more detail.

Accompanying drawing explanation

In the accompanying drawings, by way of example but not the present invention will be described in a restricted way, and wherein similar reference number refers to similar element, wherein:

Fig. 1 illustrates the example of such RF power perturbation, and it can cause plasma unstable in the transition process of one of pulsed RF signal.

Fig. 2 illustrate according to the embodiment of the present invention have plasma processing chamber and be arranged to each RF signal pulse apply state power level control simplification capacitance coupling plasma process system.

Fig. 3 illustrates the output figure of effect that to illustrate to take the photograph before between each RF signal (proactively) lock-out pulse applies relative to the time of two RF signals.

Fig. 4 illustrates situation according to an embodiment of the present invention, and wherein 60MHzRF signal has the power level of its pulse adapting to 2MHzRF signal applying state.

Fig. 5 illustrates the situation according to another embodiment of the present invention, and wherein 60MHzRF signal has the power level of its pulse adapting to 2MHzRF signal applying state.

Fig. 6 illustrates the situation according to another embodiment of the present invention, and wherein 27MHzRF signal and 60MHzRF signal have the power level of its pulse adapting to 2MHzRF signal applying state.

Fig. 7 illustrates the specimen page that following true concept map is described: under certain conditions, and non-base RF generator can not export RF power at power demand set point.

Fig. 8 illustrates the method for RF frequency for learning when base stage RF generator applies pulse the optimal tuning for non-base RF generator according to the embodiment of the present invention.

Fig. 9 illustrates the method for optimum RF power flows to the plasma load in plasma chamber when plasma chamber is provided with pulse base RF signal with at least one non-base RF signal according to the embodiment of the present invention.

Detailed description of the invention

Describe the present invention referring now to some embodiments as shown in the drawings of the present invention. In the following description, many details are stated to provide thorough understanding of the present invention. But it will be apparent that to those skilled in the art, the present invention can be implemented in the some or all of situation in not having these details. On the other hand, known processing step and/or structure will not be described in detail to avoid unnecessarily obscuring the present invention.

Various embodiment is described below, including method and technology. It should be kept in mind that the present invention also can contain the manufacture object including computer-readable medium, storage is for implementing the computer-readable instruction of the technology of the present invention on a computer-readable medium. Computer-readable medium can include the such as quasiconductor for storing computer-readable code, magnetic, optomagnetic, light or other form computer-readable medium. Further, the present invention also can contain the device for implementing embodiments of the present invention. Such device can include special and/or programmable circuit to perform the task about embodiments of the present invention. The embodiment of such device include general purpose computer and/or be properly programmed after dedicated computing equipment and can include computer/computing equipment and be applicable to the various tasks about embodiments of the present invention special/combination of programmable circuit.

Embodiments of the present invention relate to the RF power level by arranging one or more upper frequency RF signal with front taking the photograph and front control with taking the photograph pulse apply control Cement Composite Treated by Plasma with the RF power perturbation minimizing in processing procedure method and apparatus. The power level of upper frequency RF signal is determined and is then set individually in response to base stage pulsed RF signal. In other words, the power level of upper frequency RF signal is determined and is then set individually the high impulse for base stage pulsed RF signal and the low pulse for base stage pulsed RF signal.

Term as employed herein, base stage pulsed RF signal represents the low-limit frequency RF signal applying pulse. Such as, if bottom electrode is provided three RF signals (2MHz, 27MHz and 60MHz) and 2MHzRF signal applies pulse, then 2MHzRF signal represents base stage pulsed RF signal, because it is the low-limit frequency RF signal applying pulse. As another example, if to its bottom electrode (2MHz, 27MHz and 60MHz) and 2MHzRF signal with continuous wave (namely plasma processing chamber is provided three RF signals, non-pulsed mode) run and 27MHzRF signal and the applying pulse of 60MHzRF signal, then 27MHzRF signal represents base stage pulsed RF signal.

In order to illustrate term, base stage pulsed RF signal can be identical or different with main RF signal, and main RF signal represents the independent RF signal applying pulse. When multiple RF power supplys apply pulse, the one in described RF power supply can be designated as main RF power supply and independently make its main RF signal pulse. Main RF power supply can send control signal to other RF power supply so that applying impulsive synchronization. Do not require that main RF signal is the RF signal of low-limit frequency. Therefore, 27MHz pulsed RF signal can as the main RF signal of 2MHz pulsed RF signal, and vice versa. But, term as used herein base stage pulsed RF signal is the low-limit frequency RF signal applying pulse. It should be noted at this point that use main RF power supply lock-out pulse between RF power supply to apply simply to make a kind of method of applying impulsive synchronization.External circuit such as can be adopted to apply to the pulse synchronizing between all RF power supplys.

In one or more embodiment, when base RF signal applies pulse, each in other pulsed RF signal the pulse of itself and base stage pulsed RF signal apply to take the photograph before between the first preset power level and second preset power level of state synchronized alternately. First preset power level represents the power level that the high impulse for base RF signal of other pulsed RF signal is established. Second preset power level represents the power level that the low pulse for base RF signal of other pulsed RF signal is established.

For example it is assumed that plasma processing chamber is provided three RF signals applies pulse to its bottom electrode (2MHz, 27MHz and 60MHz) and 2MHz and 27MHzRF signal both with 100Hz. 2MHz base stage pulsed RF signal can apply pulse with 100Hz between 2MHz high power levels and 2MHz low-power level. 27MHzRF signal replaces before the control signal meeting in response to next autonomous RF power supply or external sync control circuit with taking the photograph between the first preset power level (it occurs in response to 2MHz high power levels) and the second preset power level (it occurs in response to 2MHz low-power level).

The preset power level of non-base stage pulsed RF signal (the 27MHzRF signal in such as previous embodiment) is determined and/or establishes reaching some desired result. Further, each in the first preset power level of non-base stage pulsed RF signal and the second preset power level all applies state separately for each pulse of base stage pulsed RF signal and establishes. So, they are determined separately for the condition of plasma during the low state of the high state and base RF signal that are present in base RF signal (the 2MHzRF signal in such as previous embodiment) and/or establish. Once these preset power level are established (such as non-base RF signal, in formula forming process), then when base stage pulsed RF signal applies pulse between its high state and its low state, the non-base RF signal control signal in response to next autonomous RF power supply or from external sync control circuit can replace in process of production (such as, in substrate processes) between the first preset power level and the second preset power level. The fact that the another kind of form of presentation of this situation is that the response of non-base stage pulsed RF signal depends not only upon that base RF signal applies pulse and depend on the state (high or low) of base RF signal.

In one or more embodiment, front take the photograph response and be used to optimize the instability of RF power in pulse applying process. Take the photograph before terminology employed herein or front take the photograph response and refer to that the compensation of RF signal and/or pulse apply to be performed with front taking the photograph rather than perform reactively. As previously discussed, reactive response occurs at matching network or when changing because the pulse of the one in other RF signal applies with the condition of plasma (for example, such as plasma impedance) in the RF power detecting of RF signal correction connection to room. In reactive response modes, after such detection occurs, this matching network or this RF power supply respond to compensate the condition of plasma change detected. Specifically, in reactive response modes, matching network or RF power supply are only made in detection and being responded afterwards.

In contrast, take the photograph in response modes front, the matching network of other RF signal or the response of RF power supply by control signal started with front taking the photograph without etc. to be detected.Such as, external control circuit and/or processor and/or computer can before send control signal with taking the photograph respond based on its knowledge that one or more of pulse in other RF signal is applied behavior/sequential with instructions match network or RF power supply. The detection that this control signal withouts waiting for response the condition of plasma that pulse is relevant is changed occurs. As another embodiment, for the one in pulsed RF signal RF generator can with other RF generator communication to provide control signal thus being begun to respond to by other RF generator. In this case, the RF generator sending control signal can as main RF generator, and other RF generator is as from RF generator. Replace the detection changed in response to article on plasma concrete conditions in the establishment of a specific crime, send control signal before main RF generator with taking the photograph to it from RF generator.

The response of response and/or other RF generator by controlling matching network with front taking the photograph, the RF power come because pulse applies instability and/or plasma perturbation are contracted by the persistent period and/or in intensity. By this way, power perturbation is reduced and plasma stability is enhanced.

With reference to accompanying drawing and discussed below, it is better understood the feature and advantage of embodiments of the present invention.

Fig. 2 illustrates that the capacitance coupling plasma of the simplification with plasma processing chamber 204 according to the embodiment of the present invention processes system 202. Although typical plasma process system can have multiple room, but the purpose in order to set forth merely illustrates a room. Additionally eliminate and well known to a person skilled in the art other details, such as machine transferring arm, Storage Box, gas supply, etc.

In the embodiment of fig. 2, upper electrode 206 is grounded, and the bottom electrode 208 representing substrate holder (substrateholder) or chuck is provided three the RF signals (2MHz, 27MHz and 60MHz) respectively from three RF power supplys 220,222 and 224 by matching network 230. Though it is shown that three RF signals and three RF power supplys, but bottom electrode 208 can be provided that few to one or and desired as many RF signal. Further, although in order to set forth the RF frequency that have selected 2MHz, 27MHz and 60MHz, if but needing to be used as different RF frequencies. Described plasma processing chamber 204 is arranged to dielectric etch.

As it is known by the man skilled in the art, the impedance of RF power supply 220,222 and 224 is carried out mating minimize reflection power and maximize power output by matching network 230 with the impedance of the plasma load in plasma processing chamber. According to the embodiment of the present invention, make the one in RF power supply as RF pulse main power source if RF power supply 220,222 is in 224 in communicating, then this RF power supply can before send control signal with taking the photograph to other RF signal so that front start these other RF signals pulse with taking the photograph applies.

Such as, RF power supply 220 (2MHzRF power supply) can as pulse main power source and via conduit 231 and 232 respectively give RF power supply 222 and 224 send numeral or analog control signal (for example, it can be the signal of telecommunication or optical signal) with instruction RF power supply 222 and 224, the pulse of their pulse applying with main 2MHzRF signal is applied (for example, with the rising edge during 2MHzRF pulse applying, trailing edge or any scheduled time) Tong Bu, without the detection that the condition of plasma waited in plasma process chamber 204 changes.

As another embodiment, RF power supply 222 (27MHzRF power supply) can as pulse main power source and via conduit 234 and 232 respectively give RF power supply 220 and 224 send numeral or analog control signal (for example, it can be the signal of telecommunication or optical signal) with instruction RF power supply 220 and 224, the pulse of their pulse applying with main 27MHzRF signal is applied (for example, with the rising edge during MHzRF pulse applying, trailing edge or any scheduled time) Tong Bu, without the detection that the condition of plasma waited in plasma process chamber 204 changes.

Alternatively, control circuit 250 can be utilized for all three RF power supply 220,222 and 224 and provide control signal, as shown. In this case, it does not have RF power supply may require that to serve as main power source and all can take the photograph ground instruction RF power supply before receiving from control circuit 250 and applies the control signal of pulse. Applying by controlling the pulse of each RF signal with front taking the photograph, RF power perturbation is minimized, as shown in FIG. 3 below.

Fig. 3 illustrates the figure of the output relative to the time of two RF signals: 2MHzRF signal 302 and 60MHzRF signal 304. 2MHzRF signal 302 applies pulse at 100Hz with 50% dutycycle between 2500W and 0W. Clear in order to set forth, in the fig. 3 embodiment, 60MHzRF signal 304 with it for the high impulse of 2MHzRF signal duration be set in first preset power level of 900W and it is for the second preset power level being set in 900W during the low pulse persistance of 2MHzRF signal equally. In the fig. 3 embodiment, 2MHz and the 60MHzRF power supply both producing these RF signals applying pulse receives control signal from common control circuit (control circuit 250 of such as Fig. 2) and thus applies pulse with before taking the photograph in a synchronous manner without the detection waiting that article on plasma concrete conditions in the establishment of a specific crime changes. Alternatively, one (such as, 2MHzRF power supply or 27MHzRF power supply) in RF power supply can as other RF power supply pulse main power source and can before send with taking the photograph control signal with other RF power supply of instruction generally synchronously apply pulse without wait article on plasma concrete conditions in the establishment of a specific crime change detection.

As seen from Figure 3, changing for each high-low of 2MHz base stage pulsed RF signal 302 or low-high, the power perturbation in 60MHzRF signal 304 is held significant lower (in the embodiments of figure 3 lower than 3%). These are illustrated by reference number 320,322,324 and 328. Compared to the situation in Fig. 2 that wherein 60MHzRF power supply runs (that is, compensating) in response to the detection of condition of plasma change in pattern of reactivity, RF power perturbation here is significantly smaller. This is because once power level set point is determined for non-base stage pulsed RF signal, then non-base stage pulsed RF signal can apply pulse between two power setting point and postpones without based on receiving control signal, thus contributing to the output of more stable RF power.

In one or more embodiment, non-base stage pulsed RF signal is (namely, higher RF frequency pulse signal) the first power level and the second power level in each can from one or more measurable plasma processing chamber parameter (for example, such as chuck bias or return RF electric current) dynamically determine. By " dynamically ", it should be appreciated that power level this is determined and such as can be formed at formula or algorithmically be done during verification of machine, or instant (on-the-fly) can complete in processing procedure.First power level of non-base stage pulsed RF signal (corresponding to the power level of non-base stage pulsed RF signal when base stage pulsed RF signal is in its high state) automatically can be determined by algorithm from the sensor measurement of one or more plasma processing chamber parameter and high state for base stage pulsed RF signal is calculated. Similarly, non-base stage pulsed RF signal the second power level (corresponding to when base stage pulsed RF signal in its low state time non-base stage pulsed RF signal power level) automatically can be determined by algorithm from the sensor measurement of one or more plasma processing chamber parameter and low state for base stage pulsed RF signal is calculated.

In this case, during the high state and low state of base stage RF pulse signal, utilize the computer of such as sequencing, sensor measurement based on one or more plasma processing chamber parameter dynamically determines and arranges non-base stage pulsed RF signal (namely, upper frequency pulsed RF signal) power level so that the ability reaching desired technological parameter represents an advantage, because the power level of the upper frequency pulsed RF power signal during the high state of base stage pulsed RF signal and during the low state of base stage pulsed RF signal is now with in the independent control knob of technique. afterwards, non-base stage pulsed RF signal is according to from main RF power supply or be externally controlled device (such as, the controller circuitry 250 of Fig. 2) and receive control signal and be converted to the second predefined power level (vice versa) from the first predefined power level simply.

It should be noted that each RF power supply is specific by the first predefined power level and the second predefined power level. In other words, 27MHz power supply can have the first predefined specific (RF-power-supply-specific) power level of RF power supply and the second predefined RF power supply certain power level of himself, and 60MHzRF power supply can have the predefined RF power supply certain power level of first different from 27MHzRF power supply and the second predefined RF power supply certain power level of himself.

In one or more embodiment, utilize the computer of such as sequencing, based on the sensor measurement of one or more plasma processing chamber parameter (such as chuck bias), the power level (that is, therefore high pulse power level and low pulse power level) of base stage pulsed RF signal also can be dynamically determined to reach desired technological parameter (such as deposition). Utilize the computer of such as sequencing, dynamically determine the power level of base stage pulsed RF signal so that the ability reaching desired technological parameter represents an advantage based on the sensor measurement of one or more plasma processing chamber parameter, because the power level of base stage pulsed RF power signal is now with in the control knob of technique.

Fig. 4 illustrates situation according to an embodiment of the present invention, and wherein 2MHzRF signal 402 carries out pulse applying with 100Hz with the dutycycle of 50% between 2500W and 0W. 60MHzRF signal 404 was taken the photograph mode in the past and was synchronized so that the high state for 2MHzRF signal, and the power level of 60MHzRF signal is at 900W during the low state of 2MHzRF signal, and the power level of 60MHzRF signal is 450W. It should be noted that, each in the two power level of 60MHzRF signal is in view of base stage RF pulse signal (such as, 2MHzRF signal) particular state (high or low) be determined separately and arrange and be determined and set reach desired process results (such as low polymer deposition, reduce wafer bias, etc.).In addition, the pulse of two RF signals of Fig. 4 occurs before applying with taking the photograph, namely, it is not necessary to the detection of the change of one or more room parameter that the detection waiting the change of article on plasma concrete conditions in the establishment of a specific crime or this condition of plasma that reflection is come because of base RF signal pulse change. So, RF power perturbation and RF plasma unstable are greatly reduced.

Fig. 5 illustrates the situation according to another embodiment of the present invention, and wherein 2MHzRF signal 502 carries out pulse applying at 100Hz with 50% dutycycle between 2500W and 0W. 60MHzRF signal 504 was taken the photograph mode in the past and was synchronized so that the high state for 2MHzRF signal, and the power level of 60MHzRF signal is at 900W. During the low state of 2MHzRF signal, the power level of 60MHzRF signal is raised to 1125W. Fig. 4 and Fig. 5 illustrates that the power level of non-base RF signal (that is, upper frequency pulsed RF signal) can be higher or lower after base stage pulsed RF signal is converted to low state from high state. Again, it should be noted that, each in the two power level of 60MHzRF signal is in view of base stage RF pulse signal (such as, 2MHzRF signal) particular state (high or low) be determined and set and be determined and set reach desired process results (such as low polymer deposition, reduce wafer bias, etc.). Additionally, the pulse of the two of Fig. 4 RF signals occurs before applying with taking the photograph, i.e. without waiting for the detection of the change of article on plasma concrete conditions in the establishment of a specific crime. So, RF power perturbation and RF plasma unstable are greatly reduced.

Fig. 6 illustrates the situation according to another embodiment of the present invention, and wherein 2MHzRF signal 602 carries out pulse applying with 100Hz with the dutycycle of 50% between 2500W and 0W. 60MHzRF signal 604 was taken the photograph mode in the past and was synchronized so that the high state for 2MHzRF signal, and the power level of 60MHzRF signal is at 500W. During the low state of 2MHzRF signal, the power level of 60MHzRF signal is raised to 625W. 27MHzRF signal 606 was taken the photograph mode in the past and was synchronized so that the high state for 2MHzRF signal, and the power level of 27MHzRF signal is at 1000W. During the low state of 2MHzRF signal, the power level of 27MHzRF signal is lowered to 250W. Again, it should be noted that, in the two power level of 60MHzRF signal each and and 27MHzRF signal the two power level in each in view of base stage RF pulse signal (such as, 2MHzRF signal) particular state (high or low) be determined and set and be determined and set reach desired process results (such as low polymer deposition, reduce wafer bias, etc.).

In the embodiment in fig 6, one of RF power supply (such as 2MHzRF power supply, 27MHzRF power supply or 60MHzRF power supply) can as main power source and can send control signal to take the photograph before other RF power supply ground lock-out pulse apply. Alternatively, external control circuit can as main signal and can send control signal to take the photograph before all three RF power supply ground lock-out pulse apply.

As discussed, the RF power level of each RF signal can be separately tuned to realize desired process results during the high state of base stage pulsed RF signal and during the low state of base stage pulsed RF signal. As embodiment, it is believed that be can by improve 2MHzRF signal RF power level increase ion energy. It is useful for increasing ion energy, may also lead to unnecessary excessive polymer deposition in some cases.2MHzRF signal applies pulse in its optimum pulse frequency and best high RF power level and the best low RF power level and may result in increase ion energy and but do not suffer excessive polymer deposition.

Once the optimum RF power level of base stage pulsed RF signal is determined and/or arranges, non-base stage pulsed RF signal is (namely, upper frequency pulsed RF signal) RF power level can be determined and arrange tuning further technique (such as tune plasma density, because the power level of upper frequency RF signal to be prone to plasma Effects of Density bigger) respectively for the low state of the high state of base stage pulsed RF signal and base stage pulsed RF signal. The different RF power levels that so these different RF pulses apply signal can serve as the discrete control knob of technique.

As discussed, owing to each pulsed RF signal is synchronized with front taking the photograph, so RF power perturbation is minimized. Even if RF signal (such as 60MHzRF signal) is defined as with continuous wave (CW) mode operation by formula, in one embodiment, this RF signal is set to apply pulse with taking the photograph also can be desirable to identical power level (such as 900W) is front during both high states of base stage pulsed RF signal (such as 2MHzRF signal), because as shown in Figure 3, compared to reactivity shimming method, so apply pulse at equal-wattage level and decrease RF power perturbation.

In one or more embodiment, the RF power level of base stage pulsed RF signal and non-base RF signal is set such that plasma is maintained in pulse applying process. In other words, plasma is not off during the low state of base stage pulsed RF signal and/or the low state of non-base stage pulsed RF signal. Keep plasma ignition to make technology controlling and process be employed more efficiently by the technique button (as previously mentioned) of independent RF power level and also make plasma disturbance minimize because plasma wipe combustion and/or light (if plasma is allowed to extinguish, wipe combustion and/or to light can be necessary) control of technique is good not as continuumpiston. So, repeatable and uniformity is strengthened.

In one or more embodiment, therefore bimodulus (bimodal) automatic frequency tuning technology and device are disclosed. In bimodulus automatic frequency tuning method, when base RF signal is from a kind of state pulse to another kind of state, with each state for base RF signal, the tuned frequency of non-base RF signal is changed with front taking the photograph guarantees that efficient and stable power exports.

Specifically, modern RF power supply can tune the RF frequency of its conveying to improve power output (such as, by changing the RF frequency being fed to load). As an example, 60MHzRF generator can be tuned RF frequency shift such as 5-10% (that is, being delivered to the +/-5%-10% of the RF frequency shift 60MHz of load).

But, such frequency shift is perform as RF generator responding when the amount that its sensor detects the RF power flowing to load changes afterwards so far. This detection tends to rely on the measurement result of the ratio (also referred to as gamma) of such as reflection power and forward power. When RF generator (such as based on some default gamma threshold values) detects and is characterized as situation that insufficient power exports, RF generator can change its tuning RF frequency efficiently power is flowed to load in frequency tuning scheme.

But, the person's character afterwards of current frequency tuning scheme often means that to have in response when plasma impedance or plasma load change delays. In this time delay, under some condition (such as when base RF signal is from a kind of state pulse to another kind of state), non-base RF generator can the normally low effect of right and wrong or can not at required power setting point (being specified by formula) transmission power until its tuned frequency be changed into the plasma load being enough to adaptive change by non-base RF generator.

One or more embodiment according to the present invention, the tuned frequency of non-base RF signal is determined in advance for each pulse condition (such as, high or low) of base RF signal. Consider this situation, for instance, when 2MHz base RF signal applies pulse at about 1kHz with 50% dutycycle. Such as, in the study stage, it was determined that when 2MHz base RF signal in its low pulse condition (namely, be pulsed into low after) time, the power output of 60MHzRF generator is efficient when 60MHzRF generator actually uses 61MHz tuned frequency to carry its RF power. Further, what was certain was that, in another embodiment, in the study stage, when 2MHzRF signal in its high impulse state (such as, after being pulsed into height) time, 60MHzRF generator is efficient when 60MHzRF generator actually uses 59MHz tuned frequency to carry its RF power.

In one or more embodiment, in process of production, 60MHzRF generator (in this embodiment be non-base RF generator) can while base RF signal is from a kind of state pulse to another kind of state before change its tuned frequency with taking the photograph. This frequency shift is taken the photograph before can be described as, because the change that non-base RF generator is on tuned frequency is not based on being made by the change on the condition of plasma of 60MHzRF generator identification or the detecting of change in impedance afterwards of coming because the pulse of base RF signal applies.

On the contrary, in the change tuned in RF frequency, non-base RF generator is synchronized so that this change occurs to guarantee that enough and/or efficient power exports when base RF signal is from a kind of state pulse to another kind of state at Best Times. Such as, based on coordinate signal (it can send by any one in 2MHzRF generator or RF generator or by the independent control circuit coordinating RF generator) and non-camp to the detection by the change on the condition of plasma of 60MHzRF generator identification or the change in impedance that comes because the pulse of base RF signal applies, 60MHzRF generator can before change its RF tuned frequency with taking the photograph. Even it is said that in general, non-base RF generator can change its tuned frequency before this while base RF signal is pulsed into another kind of pulse condition from a kind of pulse condition.

Fig. 7 illustrates the specimen page that following true concept map is described: under certain conditions, and non-base RF generator can not export RF power at power demand set point. This is situation of the prior art, for example. In the embodiment of Fig. 7, base stage 2MHzRF generator has power setting point (not showing in Fig. 7) of 9kW, and 60MHzRF generator has the power setting point of 750W. For each RF generator, these power levels being desirable to. Further, in the embodiment of Fig. 7, base stage 2MHzRF signal continues 5 seconds (from 2.2 seconds to 7.2 seconds) from high state gradual change (ramp) to low state.

In the figure 7, left vertical pivot represents the amount of the power carried by 60MHzRF generator, and right vertical pivot represents the tuned frequency of 60MHzRF generator. Two vertical pivots are marked and drawed relative to horizontal time axis. Line 702 represents the RF power quantity carried. Line 730 represents the tuned frequency of 60MHzRF generator.

It is in high impulse state at point 700,2MHzRF generators. At this point, 60MHzRF generator carries its power (line 730 during second time t=2) efficiently in the tuning RF frequency of about 61MHz.

When the time is 2.2 seconds, 2MHz base RF signal started down gradually to drop (ramplow), arrived its low state when 7.2 seconds. Sensed the change of plasma load from RF power line 702,60MHzRF generator and attempt the power setting point maintaining its 750W. At certain time point, starting from about 5 seconds places's (point 704), 60MHzRF generator is in response to changing its tuned frequency downwards the change (it is gradually dropped to low state by 2MHz base signal and causes) of the plasma load detected to improve the efficiency of RF power output.

When the time is 7.2 seconds (reference number 706 on horizontal time axis), 2MHz base RF signal is in its low state. Visible in the figure 7,60MHzRF generator the RF power quantity carried drops temporarily to about 220W from point 708 to point 710. This RF power quantity carried by 60MHzRF generator is substantially less than the 750W power setting point for 60MHzRF generator. This represent unfavorable condition.

Seek the tuning RF frequency that 60MHzRF power can be made with 2MHzRF signal to be carried in its low pulse condition at required 750W power setting point to point 712,60MHzRF generators from point 706. The tuning RF frequency of about 59.75MHz it is stabilized at point 714,60MHzRF generators. In the tuning RF frequency that this is relatively low, 60MHz generator can carry RF power at the set point of its 750W again.

The specimen page of the concept map of Fig. 7 illustrates for each pulse condition of 2MHz base signal, has the optimal tuning RF frequency for 60MHzRF generator. Further, if 60MHz generator is in mode afterwards (namely, after the change of the plasma load come because the pulse of 2MHz base RF signal applies being detected, shown in Fig. 7) change its tuning RF frequency, then can there is following situation: power setting point and RF frequency meeting are such as 60MHzRF generator can not meet its required power setting point. This figure 7 illustrates between point 706 and 712.

Fig. 8 illustrates the method for RF frequency for learning when base stage RF generator applies pulse the optimal tuning for non-base RF generator according to the embodiment of the present invention. In step 802, with pulse base RF signal and at least one non-base RF signal excitation (power) plasma chamber. In step 804, non-base RF generator is operated so that non-base RF generator can search optimum RF frequency (f1 and f2) of its high state being respectively used to base RF signal and low state with automatic tuning mode. With this automatic tuning mode, during each state of base RF signal, non-base RF generator is allowed to search the tuning RF frequency of himself. Be used as predefined RF frequency for these optimum RF frequencies (for non-base RF signal) of each state of base RF signal, and non-base RF generator when base RF signal applies pulse before take the photograph from a predefined RF frequency error factor to another predefined RF frequency.

Terminology employed herein refers to such RF frequency for the optimum RF frequency of non-base RF generator: in this RF frequency, and non-base RF generator can desirably or efficiently be carried its power (according to certain predefined standard) and/or can meet its power output set point. As discussed here, there is at least two optimum RF frequency for non-base stage generator. The two optimum RF frequency is corresponding to two alternating states of base RF signal.

It should be noted that each RF power supply is specific by the first predefined RF frequency adopted in production process and the second predefined RF frequency.In other words, 27MHz power supply can have the first predefined RF power supply specific (RF-power-supply-specific) RF frequency and the second predefined specific RF frequency of RF power supply of himself, and 60MHzRF power supply can have the those the first predefined RF power supply specific RF frequency being different from 27MHzRF power supply and the second predefined specific RF frequency of RF power supply of himself.

In one or more embodiment, other conditions all of room be preferably arranged so that they as closely as possible simulated production time condition. In another embodiment, the frequency of non-base RF generator can be manually changed optimum frequency f1 and the f2 determining the high state being respectively directed to base RF signal and low state with (such as, by measuring gamma).

In step 806, can be recorded and/or store (that is, best non-base RF frequency generator in the study stage by the production of the substrate after acquistion) process to use producing for these best non-base RF frequency generators of the high state of base RF signal and low state. In process of production, when base RF signal applies pulse, take the photograph before non-base RF generator switching rather than wait the detection of change of plasma impedance or gamma between optimum RF frequency f1 and optimum RF frequency f2.

Fig. 9 illustrates the method for optimum RF power flows to the plasma load in plasma chamber when plasma chamber is provided with pulse base RF signal with at least one non-base RF signal according to the embodiment of the present invention. In step 902, with pulse base RF signal and at least one non-base RF signal excitation (power) plasma chamber. In step 904, non-base RF generator is operated with non-automatic tuning mode. In step 906, the pulse of front synchronize non-base RF signal frequency error factor and base stage RF generator with taking the photograph applies. The synchronization taken the photograph before this makes when base RF signal applies pulse between its high state and its low state, and non-base RF generator can switch its tuned frequency between the optimal tuning frequency f1 and the optimal tuning frequency f2 of acquistion in advance of acquistion in advance. The switching of the tuned frequency of non-base RF generator can be described as before takes the photograph in process of production, because this handoff response is performed and independent of the plasma load condition sensing (that is, the detection to the change of the room parameter of the plasma load condition of this change come because the pulse of base RF signal applies of reflection) changed in synchronizing signal.

This synchronizing signal can such as by base stage RF generator, by any RF generator in multiple RF generators or sent by external synchronizing circuit or computer. In embodiments, while base RF signal is switched to another kind of state from a kind of state, the optimum RF frequency f2 of another acquistion in advance it is switched to from the optimum RF frequency f1 of an acquistion in advance with taking the photograph before non-base RF generator.

Such as, if being determined to be efficiently for the optimum RF frequency f1 of the acquistion in advance of the non-base RF generator optimum RF frequency f2 high state of base RF signal being determined to be efficiently and for the acquistion in advance of non-base RF generator for the low state of base RF signal, then non-base RF generator may be in response to synchronizing signal and is switched to the optimum RF frequency f1 of acquistion in advance when base stage RF generator is pulsed into high state. Further, non-base RF generator may be in response to synchronizing signal and is switched to the optimum RF frequency f2 of acquistion in advance when base stage RF generator is pulsed into low state.

In another embodiment, non-base RF generator can before be switched to the optimum RF frequency f2 of another acquistion in advance from the optimum RF frequency f1 of an acquistion in advance with taking the photograph, even slightly before base RF signal is switched to another kind of state from a kind of state.

In another embodiment, even slightly after base RF signal is switched to another kind of state from a kind of state, non-base RF generator can before be switched to the optimum RF frequency f2 of another acquistion in advance from the optimum RF frequency f1 of an acquistion in advance with taking the photograph.

In one or more embodiment, non-base RF signal frequency switching (such as, between the RF frequency f1 and the RF frequency f2 of acquistion in advance of acquistion in advance) taken the photograph before non-base RF generator can arrange with the power level taken the photograph before non-base RF generator and combine to improve delivery efficiency and the stability of RF power when base RF signal applies pulse. In one or more embodiment, the power level switching taken the photograph before the frequency error factor taken the photograph before non-base RF signal and/or non-base RF generator can apply Tong Bu with the pulse of base RF signal. If including multiple non-base RF signals, then the frequency of these non-base RF signals and/or available similar being arranged on before when base RF signal applies pulse as discussed for the situation of single non-base RF signal of power level switch over taking the photograph.

From the foregoing, embodiments of the present invention improve stability and the efficiency of the RF power output when base RF signal applies pulse between its high state and its low state. By changing a non-base RF generator or the RF power level of multiple non-base RF generator (if including multiple non-base RF generator) with front taking the photograph, when base RF signal applies pulse between its high state and its low state, the stability of power output is improved. By front taking the photograph switching between the optimum RF frequency for a non-base RF generator or the acquistion in advance of multiple non-base RF generator (if including multiple non-base RF generator), the efficiency of power output is improved or makes each pulse condition for base RF signal or for around exporting feasible from the height of base stage RF-low and the persistent period of low-high transformation power.

By providing these extra control knobs, technical recipe window can be opened to adapt to tightened up technological requirement, leads improved treatment and the yield of high density/high performance device.

Although the present invention is described with some preferred implementations, but also have the alternative, substitute mode and the equivalent way that fall within the scope of the present invention. It should be noted that, implement methods and apparatus of the present invention have many alternative methods. Although there is provided herein multiple embodiment, but it is intended that these embodiments and is illustrative rather than the restriction present invention.

Claims

1. the method for processing substrate in the plasma processing chamber have electrode, described plasma processing chamber has the multiple RF power supplys being coupled for providing multiple RF signals into described electrode, and described method includes:

The RF power supply in the plurality of RF power supply is made to apply pulse to produce base stage RF pulse signal,

The wherein said RF power supply made in the plurality of RF power supply applies pulse and is performed during the process of described substrate,

Wherein said base stage RF pulse signal is with the pulse between high power levels and low-power level of the first pulse frequency, wherein said base stage RF pulse signal represents a RF signal of the minimum pulse frequency in the pulse frequency in the plurality of RF signal with the plurality of RF signal, and described minimum pulse frequency is different from the RF frequency of described base stage RF pulse signal;

Send control signals to the 2nd RF power supply in the plurality of RF power supply, wherein during processing described substrate, described control signal produces before in the way of need not the change of one or more room parameter come owing to the described RF power supply made in the plurality of RF power supply applies pulse being sensed with taking the photograph; And

In response to described control signal, between the first predefined power level and the second power level being different from the described first predefined power level, the described 2nd RF power supply in the plurality of RF power supply is made to apply pulse to produce non-base stage pulsed RF signal, wherein said non-base stage pulsed RF signal represents the 2nd RF signal in the plurality of RF signal, the wherein said described 2nd RF power supply made in the plurality of RF power supply applies pulse and is performed during the process of described substrate, the described first and second predefined power levels are pre-determined during the calibration operation wherein occurred before the process of described substrate, so as the disturbance reduced in impedance of plasma, described disturbance produces when described base stage RF pulse signal pulse between described high power levels and low-power level.

2. the method for claim 1, wherein said control signal is launched from one of the plurality of RF power supply.

3. the method for claim 1, wherein said control signal is launched from the main control circuit of the outside of the plurality of RF power supply.

4. the method for claim 1, wherein the generation of the described RF power supply in the plurality of RF power supply has the RF signal of different RF frequency.

5. the method for claim 1, the wherein said first predefined power level produces during the described high power levels of described base stage RF pulse signal.

6. the method for claim 1, the wherein said second predefined power level produces during the described low-power level of described base stage RF pulse signal.

7. the method for claim 1, the described low-power level of wherein said RF pulse signal represents zero energy.

8. the method for claim 1, the wherein said second predefined power level represents zero energy.

9. the method for claim 1, the described low-power level of wherein said base stage RF pulse signal represents non-zero power.

10. the method for claim 1, the wherein said second predefined power level represents non-zero power.

11. for the method processing substrate in the plasma processing chamber have electrode, described plasma processing chamber has the multiple RF power supplys being coupled for providing multiple RF signals into described electrode, and described method includes:

Wherein said base stage RF pulse signal is with the pulse between high power levels and low-power level of the first pulse frequency, wherein said base stage RF pulse signal represents a RF signal of the minimum pulse frequency in the pulse frequency in the plurality of RF signal with the plurality of RF signal, and described first pulse frequency is different from the RF frequency of described base stage RF pulse signal;

Send control signals to the 2nd RF power supply in the plurality of RF power supply, wherein during processing described substrate, described control signal produces before in the way of need not the change of one or more room parameter come owing to the described RF power supply made in the plurality of RF power supply applies pulse being sensed with taking the photograph;And

In response to described control signal, between the first predefined RF frequency and the second predefined RF frequency being different from the described first predefined RF frequency, switch the RF frequency by the described 2nd RF power supply output in the plurality of RF power supply to produce non-base stage pulsed RF signal, wherein said non-base stage pulsed RF signal represents the 2nd RF signal in the plurality of RF signal, wherein said switching is performed during the process of described substrate by the RF frequency of the described 2nd RF power supply output in the plurality of RF power supply, the described first and second predefined RF frequencies are pre-determined during the calibration operation wherein occurred before the process of described substrate, so as the disturbance reduced in impedance of plasma, described disturbance produces when described base stage RF pulse signal pulse between described high power levels and low-power level.

12. method as claimed in claim 11, wherein said control signal is launched from one of the plurality of RF power supply.

13. method as claimed in claim 11, wherein said control signal is launched from the main control circuit of the outside of the plurality of RF power supply.

14. method as claimed in claim 11, the described RF power supply in wherein said multiple RF power supplys produces the RF signal with different RF frequency.

15. method as claimed in claim 11, the wherein said first predefined RF frequency produces during the described high power levels of described base stage RF pulse signal.

16. method as claimed in claim 11, the wherein said second predefined RF frequency produces during the described low-power level of described base stage RF pulse signal.

17. method as claimed in claim 11, the described low-power level of wherein said RF pulse signal represents zero energy.

18. method as claimed in claim 11, the wherein said second predefined RF frequency representative zero energy.

19. method as claimed in claim 11, the described low-power level of wherein said RF pulse signal represents non-zero power.

20. method as claimed in claim 11, the wherein said second predefined RF frequency representative non-zero power.

21. method as claimed in claim 11, wherein operate with non-automatic tuning mode in described processing procedure at the described RF power supply of the plurality of RF power supply.