CN101383267A - Apparatus and method for controlling voltage bias of wafer - Google Patents
Apparatus and method for controlling voltage bias of wafer Download PDFInfo
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- CN101383267A CN101383267A CNA2007101213950A CN200710121395A CN101383267A CN 101383267 A CN101383267 A CN 101383267A CN A2007101213950 A CNA2007101213950 A CN A2007101213950A CN 200710121395 A CN200710121395 A CN 200710121395A CN 101383267 A CN101383267 A CN 101383267A
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Abstract
The invention provides a wafer bias voltage control device which comprises a lower electrode, a matching network, a radio-frequency power supply, a detecting module and a control module, wherein the radio-frequency power supply is connected with the lower electrode of a plasma etching device by the matching network; the detecting module is used for detecting a token parameter which has the corresponding relation with the direct current self bias voltage of a wafer in the plasma etching device and transmitting a detecting value to the control module; the control module generates a control signal according to the detecting value and transmits the control signal to the radio-frequency power supply; and the radio-frequency power supply outputs a radio-frequency signal with given power to the lower electrode of the plasma etching device through the matching network according to the control signal to control the direct current self bias voltage of the wafer. The invention also provides a method for controlling the wafer bias voltage. The device and the method for controlling the wafer bias voltage can reliably detect and control the bias voltage on the wafer in real time, and a prospective and stable technical result can be obtained.
Description
Technical field
The present invention relates to microelectronics technology, in particular to the apparatus and method that in semiconductor processing techniques, are used for the control wafer bias voltage.
Background technology
Along with the high speed development of electronic technology, people are more and more higher to the integrated level requirement of integrated circuit, and the working ability of semiconductor device constantly improves in this enterprise that will seek survival the product integrated circuit.At present, extensive using plasma lithographic technique in the processing of semiconductor device, manufacture process.So-called plasma etching technology refers to, reacting gas produces the plasma that ionization forms the atom, molecule and the free radical isoreactivity particle that contain a large amount of electronics, ion, excitation state under the exciting of radio-frequency power, these active particles with (for example be etched object, various physics and chemical reaction take place and form volatile product in surface wafer), thereby the performance of the feasible body surface that is etched changes.
In above-mentioned active particle, because electronics is lighter than cation, in the identical time, the quantity that electronics drops on wafer surface is more than ion, and therefore, the stable back of question response wafer surface can form DC auto-bias.This DC auto-bias can attract ion isoreactivity particle positively charged in the plasma to wafer surface accelerated motion, and the bombardment wafer is to reach the process results of expection.The big young pathbreaker of above-mentioned DC auto-bias influences the bombarding energy of positively charged ion isoreactivity particle, and then also will influence some parameter in the plasma etch process, for example etch rate, deposition rate etc.
At present, in the overwhelming majority's semiconductor processing equipment such as plasma etching equipment, for increasing DC auto-bias on the wafer, and then correspondingly increase the energy of positively charged ion isoreactivity particle, need add radio frequency (RF) power supply usually and apply rf excitation signal with the bottom electrode of article on plasma body etching apparatus.Yet the radiofrequency signal that is applied on the bottom electrode tends to fluctuate, and the fluctuation of radiofrequency signal can cause the fluctuation of DC auto-bias on the wafer, and then influences the stability of technical process.Therefore,, be necessary the power output of radio-frequency power supply is controlled, obtaining expection and stable radiofrequency signal, and then on wafer, obtain the DC auto-bias of stable expection size for stability that guarantees technical process and the process results that obtains expection.
In existing plasma etching equipment, adopt the open loop control strategy to control the power output of radio-frequency power supply usually.Fig. 1 just shows a kind of like this bottom electrode control structure of typical plasma etching equipment, and wherein, radio-frequency power supply links to each other with bottom electrode via matching network.Usually, preestablish the power output of radio-frequency power supply, make radio-frequency power supply impose on fixed radiofrequency signal to bottom electrode via matching network, thus the DC auto-bias on the control wafer.
As for the DC auto-bias of how measuring on the wafer, prior art is inclined to such method that adopts more: promptly, 1/2 this general rule that is about the radio-frequency voltage peak-to-peak value on the bottom electrode according to the DC auto-bias on the wafer, at first measure the peak-to-peak value be applied to the radiofrequency signal on the bottom electrode, then with above-mentioned measured value divided by 2 values that promptly obtain the DC auto-bias on the wafer.Although adopt above-mentioned control device or control method to control the DC auto-bias on the wafer, there is following defective inevitably in it:
One, because matching network itself just has the loss of signal, and this loss of signal changes and can not estimate, therefore above-mentioned predefined radio-frequency power supply power output can not all stably transfer to bottom electrode; Moreover, owing to adopted the open loop control strategy, so above-mentioned control device and control method can not automatically be regulated the set point of radio-frequency power supply power output in real time according to the actual value of the DC auto-bias on the wafer, that is to say, when adopting open loop control strategy of the prior art, the set point of radio-frequency power supply power output is uncontrollable, the so also DC auto-bias on the control wafer exactly just, thereby also just that can not obtain expecting and stable process results.
They are two years old, found through experiments, though described DC auto-bias mainly is to be produced by the radiofrequency signal that is applied on the bottom electrode, but it also can be subjected to the influence of other technological parameters simultaneously, therefore, if process conditions change, then the DC auto-bias of measuring according to aforementioned general rule is with not accurate enough.So the technical process of carrying out based on this DC auto-bias also will depart from the technological effect of expection.
Therefore, need to provide a kind of new control method and control device urgently, with measure exactly and control wafer on DC auto-bias, and then obtain expection and stable process results.
Summary of the invention
For solving the problems of the technologies described above, the invention provides a kind of apparatus and method of control wafer bias voltage, it can be measured and the control wafer bias voltage in real time reliably, and can obtain to expect and stable process results.
For this reason, the invention provides a kind of device of control wafer bias voltage, comprise bottom electrode, matching network, radio-frequency power supply, described radio-frequency power supply links to each other with the bottom electrode of semiconductor processing equipment via matching network.This device also comprises detection module and control module, and wherein said detection module is used for detecting the characterization parameter that has corresponding relation with the wafer DC auto-bias of semiconductor processing equipment, and with its transmitting measured values to control module; Described control module produces control signal according to the measured value from described detection module, and described control signal is transferred to radio-frequency power supply; Described radio-frequency power supply is exported the radiofrequency signal of given power according to described control signal, and described radiofrequency signal is applied to the bottom electrode of semiconductor processing equipment via matching network, to realize the control to the wafer DC auto-bias.
Preferably, described control module comprises node microcontroller and technical module controller.Wherein, described technical module controller is used for transmitting wafer DC auto-bias set point to the node microcontroller, and reception is from the wafer DC auto-bias measured value of described node microcontroller, with real-time monitor wafer DC auto-bias control procedure and whole semiconductor processes process; Described node microcontroller is used for according to producing control signal from the measured value of described detection module and from the wafer DC auto-bias set point of described technical module controller, and described control signal transferred to radio-frequency power supply, export the radiofrequency signal of given power to control described radio-frequency power supply.
Preferably, described node microcontroller comprises conversion evaluation unit, control algolithm unit and communication unit.Wherein, store the corresponding relation between described characterization parameter and the wafer DC auto-bias in the described conversion evaluation unit, after described conversion evaluation unit receives characterization parameter measured value from detection module, by inquiring about described corresponding relation or passing through the function inverse transformation, described characterization parameter measured value is converted to corresponding with it wafer DC auto-bias measured value, and transmits it to described control algolithm unit and communication unit; Described communication unit is used to set up the data transmission channel between described node microcontroller and the technical module controller, realize the transfer of data between the two, promptly, from the set point of described technical module controller acquisition wafer DC auto-bias, and the measured value that sends the wafer DC auto-bias in real time to described technical module controller; Described control algolithm unit is used for producing control signal according to wafer DC auto-bias measured value and wafer DC auto-bias set point, and described control signal transferred to radio-frequency power supply, carry out automatic setting with power output, thereby realize close loop negative feedback control the wafer DC auto-bias to radio-frequency power supply.
Preferably, described characterization parameter be radiofrequency signal these parameters of voltage, electric current, power, impedance and phase angle one of them; Correspondingly, described detection module comprises and the corresponding detecting element of described characterization parameter.
Preferably, described device also comprises: mould/number conversion circuit and D/A switch circuit.Wherein, it is digital signal corresponding that described mould/number conversion circuit is used for the analog signal conversion from the expression characterization parameter measured value that detects module, and transmits it to described node microcontroller; Described D/A switch circuit is used for the digital quantity control signal from the node microcontroller is converted to the analog quantity control signal, and transmits it to radio-frequency power supply.
The present invention also provides a kind of method of control wafer bias voltage, and it comprises the steps: 1) detect with semiconductor processing equipment in the wafer DC auto-bias have the characterization parameter of corresponding relation; 2) measured value that obtains according to step 1) produces control signal; 3) radio-frequency power supply is exported the radiofrequency signal of given power according to described control signal, and it is applied to the bottom electrode of semiconductor processing equipment via matching network, to realize the control to the wafer DC auto-bias.
Preferably, before described step 1), also comprise the steps: A) wafer DC auto-bias when measuring corresponding different radiofrequency signal voltage effective values; B) draw functional relation between radiofrequency signal voltage effective value and the wafer DC auto-bias by the method for fitting; C) store described functional relation with the form of slope, deviation or tables of data.
Preferably, described step 2) specifically comprise the steps: 21) by the described corresponding relation of inquiry or by the function inverse transformation, described characterization parameter measured value is converted to corresponding with it wafer DC auto-bias measured value; 22) produce control signal according to wafer DC auto-bias measured value and wafer DC auto-bias set point, carry out automatic setting, thereby realize close loop negative feedback control the wafer DC auto-bias with power output to radio-frequency power supply.
Preferably, in described step 21) also comprise such step afterwards: promptly, with described wafer DC auto-bias transmitting measured values to host computer, so that ipc monitor wafer DC auto-bias control procedure and whole semiconductor processes process.
Preferably, in described step 22) also comprise before from the step of host computer reception wafer DC auto-bias set point.
Preferably, in described step 1) and step 2) between also comprise mould/number conversion step, be digital signal corresponding with the analog signal conversion that will represent the characterization parameter measured value; In described step 2) and step 3) between also comprise the D/A switch step, so that the digital quantity control signal is converted to the analog quantity control signal.
Preferably, described characterization parameter be radiofrequency signal these parameters of voltage, electric current, power, impedance and phase angle one of them.
By technique scheme as can be seen, the apparatus and method of control wafer bias voltage provided by the invention can be controlled the DC auto-bias on the wafer by making up the close-loop feedback control system, and can obtain technological parameters such as good etch rate and deposition rate, thereby reduced under the same process condition, between wafer and the wafer, the difference that causes by the instability of wafer DC auto-bias between chamber and the chamber.
In addition, in the preferred embodiment of the apparatus and method of control wafer bias voltage provided by the invention, owing to adopted distributed close-loop feedback control system, for example promptly adopted the such specific resources of node microcontroller to handle special duty relevant in semiconductor machining/treatment process process with the control of wafer DC auto-bias, and only be responsible for the control information of node microcontroller intercorrelation and monitor its ruuning situation in real time as the technical module controller of host computer, do not participate in concrete control computing work, this will accelerate the response speed of signal greatly, improve information processing capability.Simultaneously, adopt above-mentioned specific resources to handle above-mentioned special duty and also can avoid occurring causing the problem of whole system paralysis, thereby improved the reliability of whole system because of link in the system loses efficacy.
Description of drawings
Fig. 1 is the lower electrode arrangement schematic diagram of control wafer DC auto-bias in the prior art;
Fig. 2 is the principle schematic of the device of control wafer bias voltage of the present invention;
Fig. 3 is the structural representation of a specific embodiment of device of control wafer bias voltage of the present invention;
Fig. 4 is the flow chart of a specific embodiment of method of control wafer bias voltage of the present invention.
Embodiment
The technological core of the apparatus and method of control wafer bias voltage provided by the invention is, come the DC auto-bias on the wafer is controlled by making up close-loop feedback control system (especially distributed close-loop feedback control system), to remedy the deficiency of open loop control strategy in the prior art.For making those skilled in the art person understand technical scheme of the present invention better, be described in detail below in conjunction with the apparatus and method of accompanying drawing to control wafer bias voltage provided by the invention.See also Fig. 2, the device of wafer DC auto-bias comprises in the control plasma etching equipment provided by the invention: radio-frequency power supply 110, matching network 120, bottom electrode 130, detection module 140 and control module 150.
Wherein, radio-frequency power supply 110 is by the radiofrequency signal of matching network 120 to the given power of bottom electrode 130 outputs of plasma etching equipment.
In the actual process process, directly the reaction chamber inside at plasma etching equipment is very difficult to the DC auto-bias measurement on the wafer, and the direct contact wafer of popping one's head in also can bring negative effects such as pollution to wafer.For this reason, can select there is corresponding relation and the parameter being convenient to measure is used as characterization parameter, obtain the value of DC auto-bias by measuring this characterization parameter indirectly with the wafer DC auto-bias.Because the DC auto-bias on the wafer mainly is to be produced by the radiofrequency signal that is loaded on the bottom electrode, so parameter relevant with this radiofrequency signal, as the parameters such as voltage, electric current, power, impedance and phase angle of radiofrequency signal all with wafer on DC auto-bias have corresponding relation, and can reflect the size of wafer DC auto-bias, thereby all can be used as characterization parameter.After determining characterization parameter, detection module 140 just can be by detecting the size that this characterization parameter obtains the wafer DC auto-bias indirectly.Detection module 140 transmits the measured value of detected characterization parameter to control module 150.
Particularly, at first, detect the characterization parameter of representing the wafer DC auto-bias by detection module 140, and its measured value is carried out transferring to control module 150 after mould/number conversion; Then, control module 150 calculates the value of wafer DC auto-bias, and will be worth the measured value as the wafer DC auto-bias according to testing this definite characterization parameter and the functional relation between the wafer DC auto-bias in advance.Control module 150 compares the set point of the wafer DC auto-bias measured value of wafer DC auto-bias and storage in advance or by I/O interface input, obtain the difference between the two, then described difference is calculated according to the expectant control algorithm, obtain control signal corresponding, and this control signal transferred to radio-frequency power supply 110, carry out automatic setting in order to power output, and then realize close loop negative feedback control the wafer DC auto-bias to radio-frequency power supply 110.
Be appreciated that determine characterization parameter after, the wafer DC auto-bias in the time of can utilizing experiment to measure the different characterization parameter of correspondence under different technology conditions is determined the corresponding relation of DC auto-bias on this characterization parameter and the wafer by method such as fit.
Below in conjunction with Fig. 3 a specific embodiment of the device of control wafer bias voltage provided by the invention is elaborated.In the present embodiment, selection can reflect indirectly that the radiofrequency signal voltage of (sign) wafer DC auto-bias size is as characterization parameter.
As shown in Figure 3, the device of the control wafer bias voltage in the present embodiment comprises: bottom electrode, matching network, radio-frequency power supply, voltage sensor, mould/number conversion circuit, node microcontroller, D/A switch circuit, technical module controller (in the present embodiment, it is a host computer) etc.Described radio-frequency power supply links to each other with bottom electrode via matching network.
Wherein, voltage sensor is used to detect the voltage that is applied to the radiofrequency signal on the bottom electrode, and with its transmitting measured values to mould/number conversion circuit.Particularly, voltage sensor receives the radio-frequency voltage AC signal of drawing from bottom electrode, after a series of processing such as dividing potential drop, rectification and filtering, and the voltage effective value signal that output is corresponding with it.Because this signal is an analog quantity, and the input signal that the node microcontroller requires is a digital quantity, so need mould/number conversion circuit be set between this voltage sensor and node microcontroller, like this, the voltage effective value signal of voltage sensor output just need transfer to mould/number conversion circuit earlier.
Mould/number conversion circuit will carry out mould/number conversion from the analog signal of the expression voltage effective value of voltage sensor, that is, and and the digital signal that described analog signal conversion can be discerned for the node microcontroller, and transmit it to the node microcontroller.
The node microcontroller is according to producing control signal from mould/number conversion circuit corresponding to the voltage measuring value of wafer DC auto-bias and from the set point of technical module controller, and this control signal transferred to the D/A switch circuit, thereby the power output to radio-frequency power supply is controlled, and then the control wafer bias voltage.
Be appreciated that, because the control signal of node microcontroller output is a digital quantity, and the input signal that the controlled device radio-frequency power supply requires is an analog quantity, so need between the input of the output of node microcontroller and radio-frequency power supply the D/A switch circuit be set.
The D/A switch circuit will convert the desired analog signal of radio-frequency power supply from the digital controlled signal of node microcontroller to, and its set point as the radio-frequency power supply power output is transferred to radio-frequency power supply.
Radio-frequency power supply is exported the radiofrequency signal of given power according to this set point, and it is applied to bottom electrode via matching network.
The technical module controller is used for monitoring in real time whole technical process, and sends the set point of wafer DC auto-bias to the node microcontroller, and receives the measured value from the wafer DC auto-bias of node microcontroller.
In the present embodiment, the node microcontroller specifically comprises following unit: conversion evaluation unit, control algolithm unit and communication unit.
Wherein, preserve the voltage effective value of the radiofrequency signal on the bottom electrode that obtains according to experiment and the corresponding relation between the wafer DC auto-bias in the conversion evaluation unit.This conversion evaluation unit connects aforementioned mould/number conversion circuit and control algolithm unit.After the conversion evaluation unit receives digital signal from the expression voltage effective value of mould/number conversion circuit, by inquiring about aforementioned corresponding relation or passing through the function inverse transformation, the digital signal of described expression voltage effective value is converted to the value of wafer DC auto-bias in the actual process process, and with its measured value as the wafer DC auto-bias.
Communication unit connects control algolithm unit and technical module controller, be used to set up the data transmission channel between node microcontroller and the technical module controller, to realize the transfer of data between the two, promptly, obtain the set point of wafer DC auto-bias from the technical module controller, and the measured value of the wafer DC auto-bias of transformation into itself's evaluation unit sends to the technical module controller in real time in the future, so that the technical module controller is monitored whole technical process in real time.
The control algolithm unit produces control signal according to the measured value of wafer DC auto-bias and the set point of wafer DC auto-bias, and this control signal transferred to radio-frequency power supply, thereby realize automatic setting, and then realize close loop negative feedback control the wafer DC auto-bias to the radio-frequency power supply power output.Particularly, the control algolithm unit in the future measured value of the wafer DC auto-bias of transformation into itself's evaluation unit compares with set point from the wafer DC auto-bias of communication unit, and the difference of the two is carried out predetermined algorithm calculate, finally obtain the set point of radio-frequency power supply power output, and export this set point of radio-frequency power supply power output to radio-frequency power supply, carry out automatic setting with power output to radio-frequency power supply.
It is pointed out that in actual applications and also can select similar characterization parameter, for example can select electric current, power and the impedance of radiofrequency signal and phase angle etc.Be that different characterization parameters need be equipped with different detection means (transducer) and measures, for example, selecting the voltage parameter of radiofrequency signal in the present embodiment is characterization parameter, has therefore correspondingly selected for use voltage sensor as measuring element.
Be understandable that the closed-loop control system that is adopted among the present invention both can be the distributed close-loop feedback control system described in the previous embodiment, also can be centralized close-loop feedback control system.If the centralized close-loop feedback control of employing system, node microcontroller then shown in Figure 3 and technical module controller unite two into one, for example the function with the node microcontroller also is integrated in the technical module controller, in other words, functions such as signals collecting, processing, calculating, control all are integrated in this controller of technical module controller.Like this, the technical module controller just becomes the controller of a multitask.Yet, as the controller of multitask, need to consider the balance of entire controller system resource allotment, therefore, respond fast-changing bottom layer signal this respect reliably in real time, aforementioned distributed close-loop feedback control system is better than centralized close-loop feedback control system.In addition, if the centralized close-loop feedback control of employing system, because the controlling unit of wafer DC auto-bias is integrated in the upper system of technical module controller, the working condition of this controlling unit can directly influence the work of entire controller, therefore, distributed close-loop feedback control system also is better than centralized close-loop feedback control system aspect reliability.This shows,, preferably adopt distributed close-loop feedback control system although the present invention can adopt centralized close-loop feedback control system or distributed close-loop feedback control system.
The present invention also provides a kind of method of control wafer bias voltage.Be elaborated below in conjunction with accompanying drawing 4.
See also Fig. 4, a specific embodiment of the method for control wafer bias voltage provided by the invention comprises preparation process and technological experiment process.In the present embodiment, with the voltage of radiofrequency signal as characterization parameter.
The following preparation process that describes in detail earlier.So-called preparation refers to, and the wafer DC auto-bias when measuring corresponding different radiofrequency signal voltage effective values in advance by experiment draws functional relation between the two by method such as fit then, and this functional relation is stored in the node microcontroller.Described preparation specifically comprises the steps:
Step 410 is placed the experiment wafer on the indoor electrostatic chuck of plasma etching device reaction cavity.
Step 420, radio-frequency power supply applies radiofrequency signal by matching network to bottom electrode.
Step 430, the wafer DC auto-bias when measuring corresponding different radiofrequency signal voltage effective values.
Step 440 draws functional relation between radiofrequency signal voltage effective value and the wafer DC auto-bias by method such as fit, and with the form of slope, deviation or tables of data described functional relation is stored in the node microcontroller.
Promptly finished the preparation process by above-mentioned steps 410 to step 440.
Describe operation principle and the course of work of method in actual etching technics of control wafer bias voltage provided by the invention below again in detail.
At first, execution in step 510 promptly, when engineer testing begins, is placed wafer to be etched on electrostatic chuck.
Then, execution in step 520 applies radiofrequency signal via matching network to bottom electrode by radio-frequency power supply.
Again, execution in step 530 adopts voltage sensor that the voltage effective value that is applied to the radiofrequency signal on the bottom electrode is measured, and with transmitting measured values to mould/number conversion circuit.
Again, execution in step 540, mould/number conversion circuit is converted to the discernible digital signal of node microcontroller with this analog signals, and transmits it to the node microcontroller after receiving voltage effective value from voltage sensor.
Again, execution in step 550, after the conversion evaluation unit of node microcontroller receives digital signal from the expression voltage effective value of mould/number conversion circuit, by tabling look-up or the function inverse transformation obtains and the corresponding wafer DC auto-bias of this voltage effective value measured value.
Again, execution in step 560, the communication unit of node microcontroller receives the wafer DC auto-bias duty setting signal from the technical module controller, and transmits it to the control algolithm unit of node microcontroller.
Again, execution in step 570, the control algolithm unit of node microcontroller compares above-mentioned wafer DC auto-bias measured value and wafer DC auto-bias set point, and the difference of the two is carried out algorithm computation, obtain the digital quantity control signal, and this control signal is transferred to the D/A switch circuit.
Again, execution in step 580 after the D/A switch circuit receives above-mentioned digital quantity control signal, is converted into the analog quantity control signal that radio-frequency power supply can be discerned, and its set point as the radio-frequency power supply power output is input to radio-frequency power supply.
At last, execution in step 590, radio-frequency power supply is exported the radiofrequency signal of given power according to this power output set point, and this radiofrequency signal is transferred to the bottom electrode of plasma etching equipment via matching network.
Repeat above-mentioned steps 530 to step 590, promptly realized adopting the bias voltage on the close-loop feedback control system real-time stabilization ground control wafer.
Similar with the device of aforementioned control wafer DC auto-bias, the method for control wafer bias voltage provided by the invention can adopt distributed close-loop feedback control system or centralized close-loop feedback control system equally, does not repeat them here.
As for node microcontroller that in the apparatus and method of control wafer bias voltage provided by the invention, is adopted and technical module controller, they can be any microcontrollers that can finish aforementioned functional, for example can be single-chip microcomputer, DSP (digital signal processor), ARM microcontrollers such as (AdvancedRISC Machines), but and not only be confined to this.
By foregoing description as can be seen, the apparatus and method of control wafer bias voltage provided by the invention are by making up close-loop feedback control system (preferably adopt distributed close-loop feedback control system), the bias voltage on the control wafer stably, obtain technological parameters such as good etch rate and deposition rate, thereby reduced under the same process condition, between wafer and the wafer, the difference that causes by the instability of wafer DC auto-bias between chamber and the chamber.
Particularly, when the apparatus and method of control wafer bias voltage provided by the invention adopt distributed close-loop feedback control system, handle special duty relevant in the etching process owing to for example adopted the such specific resources of node microcontroller with the control of wafer DC auto-bias, promptly, with the signal acquisition process in the wafer DC auto-bias closed-loop control system, calculate, functions such as control are separated from the technical module controller, be placed on one independently the node microcontroller (this node microcontroller is equivalent to a bottom layer node of upper strata technical module controller, all functions relevant with the closed-loop control of wafer DC auto-bias are all finished in the node of this bottom) the middle realization, and only be responsible for the control information of node microcontroller intercorrelation and monitor its ruuning situation in real time as the technical module controller of host computer, do not participate in concrete control computing work, therefore, this will accelerate the response speed of signal greatly, improve information processing capability.Simultaneously, adopt above-mentioned specific resources to handle above-mentioned special duty and also can avoid occurring causing the problem of whole system paralysis, thereby improved the reliability of whole system because of link in the system loses efficacy.
The apparatus and method that it is pointed out that control wafer bias voltage provided by the invention not only are applied to the described plasma etching equipment of previous embodiment, also can be applied to the semiconductor processing equipment that other are fit to.
Be understandable that above execution mode only is the illustrative embodiments that adopts for principle of the present invention is described, yet the present invention is not limited thereto.For those skilled in the art, without departing from the spirit and substance in the present invention, can make various modification and improvement, these modification and improvement also are considered as protection scope of the present invention.
Claims (12)
1. the device of a control wafer bias voltage comprises bottom electrode, matching network, radio-frequency power supply, and described radio-frequency power supply links to each other with the bottom electrode of semiconductor processing equipment via matching network, it is characterized in that also comprising detection module and control module, wherein
Described detection module is used for detecting the characterization parameter that has corresponding relation with the wafer DC auto-bias of semiconductor processing equipment, and with its transmitting measured values to control module;
Described control module produces control signal according to the measured value from described detection module, and described control signal is transferred to radio-frequency power supply;
Described radio-frequency power supply is exported the radiofrequency signal of given power according to described control signal, and described radiofrequency signal is applied to the bottom electrode of semiconductor processing equipment via matching network, to realize the control to the wafer DC auto-bias.
2. the device of control wafer bias voltage as claimed in claim 1 is characterized in that, described control module comprises node microcontroller and technical module controller, wherein
Described technical module controller is used for transmitting wafer DC auto-bias set point to the node microcontroller, and reception is from the wafer DC auto-bias measured value of described node microcontroller, with real-time monitor wafer DC auto-bias control procedure and whole semiconductor processes process;
Described node microcontroller is used for according to producing control signal from the measured value of described detection module and from the wafer DC auto-bias set point of described technical module controller, and described control signal transferred to radio-frequency power supply, export the radiofrequency signal of given power to control described radio-frequency power supply.
3. the device of control wafer bias voltage as claimed in claim 2 is characterized in that, described node microcontroller comprises conversion evaluation unit, control algolithm unit and communication unit, wherein
Store the corresponding relation between described characterization parameter and the wafer DC auto-bias in the described conversion evaluation unit, after described conversion evaluation unit receives characterization parameter measured value from detection module, by inquiring about described corresponding relation or passing through the function inverse transformation, described characterization parameter measured value is converted to corresponding with it wafer DC auto-bias measured value, and transmits it to described control algolithm unit and communication unit;
Described communication unit is used to set up the data transmission channel between described node microcontroller and the technical module controller, realize the transfer of data between the two, promptly, obtain wafer DC auto-bias set point from described technical module controller, and send wafer DC auto-bias measured value to described technical module controller in real time;
Described control algolithm unit is used for producing control signal according to wafer DC auto-bias measured value and wafer DC auto-bias set point, and described control signal transferred to radio-frequency power supply, carry out automatic setting with power output, thereby realize close loop negative feedback control the wafer DC auto-bias to radio-frequency power supply.
4. the device of control wafer bias voltage as claimed in claim 1 is characterized in that, described characterization parameter be radiofrequency signal these parameters of voltage, electric current, power, impedance and phase angle one of them; Correspondingly, described detection module comprises and the corresponding detecting element of described characterization parameter.
5. as the device of each described control wafer bias voltage in the claim 1 to 4, it is characterized in that also comprising: mould/number conversion circuit and D/A switch circuit, wherein
It is digital signal corresponding that described mould/number conversion circuit is used for the analog signal conversion from the expression characterization parameter measured value that detects module, and transmits it to described node microcontroller;
Described D/A switch circuit is used for the digital quantity control signal from the node microcontroller is converted to the analog quantity control signal, and transmits it to radio-frequency power supply.
6. the method for a control wafer bias voltage is characterized in that, comprises the steps:
1) detect with semiconductor processing equipment in the wafer DC auto-bias have the characterization parameter of corresponding relation;
2) measured value that obtains according to step 1) produces control signal;
3) radio-frequency power supply is exported the radiofrequency signal of given power according to described control signal, and it is applied to the bottom electrode of semiconductor processing equipment via matching network, to realize the control to the wafer DC auto-bias.
7. the method for control wafer bias voltage as claimed in claim 6 is characterized in that, also comprises the steps: before described step 1)
Wafer DC auto-bias when A) measuring corresponding different radiofrequency signal voltage effective values;
B) draw functional relation between radiofrequency signal voltage effective value and the wafer DC auto-bias by the method for fitting;
C) store described functional relation with the form of slope, deviation or tables of data.
8. the method for control wafer bias voltage as claimed in claim 6 is characterized in that, described step 2) specifically comprise the steps:
21) by the described corresponding relation of inquiry or by the function inverse transformation, described characterization parameter measured value is converted to corresponding with it wafer DC auto-bias measured value;
22) produce control signal according to wafer DC auto-bias measured value and wafer DC auto-bias set point, carry out automatic setting, thereby realize close loop negative feedback control the wafer DC auto-bias with power output to radio-frequency power supply.
9. the method for control wafer bias voltage as claimed in claim 8, it is characterized in that, in described step 21) also comprise such step afterwards: promptly, with described wafer DC auto-bias transmitting measured values to host computer, so that ipc monitor wafer DC auto-bias control procedure and whole semiconductor processes process.
10. the method for control wafer bias voltage as claimed in claim 8 is characterized in that, in described step 22) also comprise before from the step of host computer reception wafer DC auto-bias set point.
11. the method for control wafer bias voltage as claimed in claim 6 is characterized in that:
In described step 1) and step 2) between also comprise mould/number conversion step, be digital signal corresponding with the analog signal conversion that will represent the characterization parameter measured value;
In described step 2) and step 3) between also comprise the D/A switch step, so that the digital quantity control signal is converted to the analog quantity control signal.
12. the method as each described control wafer bias voltage in the claim 6 to 11 is characterized in that, described characterization parameter be radiofrequency signal these parameters of voltage, electric current, power, impedance and phase angle one of them.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN106226577A (en) * | 2015-06-02 | 2016-12-14 | 朗姆研究公司 | The Larger Dynamic scope RF voltage sensor of voltage model RF biasing application and method |
| CN106298615A (en) * | 2015-05-27 | 2017-01-04 | 北京北方微电子基地设备工艺研究中心有限责任公司 | Electrostatic chuck, reaction chamber and semiconductor processing equipment |
| CN106702335A (en) * | 2015-11-13 | 2017-05-24 | 北京北方微电子基地设备工艺研究中心有限责任公司 | Lower electrode and semiconductor processing equipment |
| CN110752137A (en) * | 2019-11-01 | 2020-02-04 | 北京北方华创微电子装备有限公司 | Bias control method and device and semiconductor processing equipment |
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| CN106298615A (en) * | 2015-05-27 | 2017-01-04 | 北京北方微电子基地设备工艺研究中心有限责任公司 | Electrostatic chuck, reaction chamber and semiconductor processing equipment |
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| CN112017931A (en) * | 2019-05-30 | 2020-12-01 | 北京北方华创微电子装备有限公司 | Method applied to plasma system and related plasma system |
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| CN110752137B (en) * | 2019-11-01 | 2022-04-22 | 北京北方华创微电子装备有限公司 | Bias control method and device and semiconductor processing equipment |
| CN113035677A (en) * | 2019-12-09 | 2021-06-25 | 中微半导体设备(上海)股份有限公司 | Plasma processing apparatus and plasma processing method |
| CN113035677B (en) * | 2019-12-09 | 2023-01-24 | 中微半导体设备(上海)股份有限公司 | Plasma processing apparatus and plasma processing method |
| CN112345814A (en) * | 2020-10-30 | 2021-02-09 | 北京北方华创微电子装备有限公司 | DC bias detection method, device, jig and lower electrode system |
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