CN102931045A - Method for processing etching process monitoring signal and etching end-point control method - Google Patents
Method for processing etching process monitoring signal and etching end-point control method Download PDFInfo
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Abstract
The invention discloses a method for processing an etching process monitoring signal and an etching end-point control method. The method for processing the etching process monitoring signal comprises the following steps of: dividing a change curve which reflects the real-time etching signal strength of a plasma etching process into an initial stage, a stable reaction stage, an etching ending stage and an etching completion stage according to the change condition of signal strength; determining a reference judgment area in the stable reaction stage, wherein the reference judgment area occupies 30 to 80 percent of the stable reaction stage, and certain distance is formed between an end point of the reference judgment area and a start point of the etching ending stage; dividing the reference judgment area into n time areas, and acquiring an average value of etching signal strength in each time area, wherein n is an integer of more than 1; and setting a maximum value or a minimum value in all average values as a reference value for etching end-point signal judgment. By adoption of the methods provided by the invention, a practical plasma etching process can be accurately reflected, and requirements of various situations can be met.
Description
Technical field
The present invention relates to semiconductor etching process, relate in particular to a kind of processing method and etching terminal control method of plasma etch process pilot signal.
Background technology
Along with the continuous increase of device integration density and complexity in the integrated circuit, more strict requirement has been proposed for the control of semiconductor processes.And reaction chamber is after after a while operation, and its inner state can change, and often drifts about such as parameters such as plasma density, electron temperature, free radical density, gas flow and silicon temperatures, and this can affect the carrying out of etching technics.Therefore, need the ruuning situation in the plasma etching cavity to monitor, and etching process is carried out FEEDBACK CONTROL, and then guarantee stability and the consistency of etching technics.
Optical emission spectroscopy (OES) is a kind of common etching technics control method.Atom in the plasma or molecule after excitation state, can be launched the light of specific wavelength by electron excitation in turning back to another energy state process.The wavelength of the light wave that excites of homoatomic or molecule is not different, and the light intensity of light wave changes and reflects that plasma Atom or molecular concentration change.The characteristic spectral line (OES characteristic spectral line) that OES can reflect the plasma etching change in process, form the plasma of closely-related material with plasma chemistry extracts, variation by its characteristic spectral line signal strength signal intensity of real-time detection, provide the information of the response situation in the plasma etch process, the method for the actual conditions in the accurate response etching process.
The plasma etching process generally is divided into etching and begins-stablize reaction-3 processes of etching end, indoor at plasma etch chamber, reactant in the plasma and product radical concentration begin can change with the etching terminal place in etching, in the process of stable reaction, reactant and product radical concentration are substantially constant.Accordingly, the variation of real time spectrum signal (OES characteristic spectral line) can be divided at least 3 stages: light plasma stage-stablize the stage of reaction-reaction and stop (etching terminal end point).Chemical gas in OES characteristic spectral line and the plasma and the dielectric material of institute's etching are relevant, and OES characteristic spectral line signal strength signal intensity is directly proportional with reactant and product radical concentration.Lighting plasma during the stage, etching begins, and the representative radical concentration of reaction product rises, and its intensity of spectral line sharply rises; Stablizing the stage of reaction, various courses of reaction reach dynamic equilibrium, and the representative radical concentration of reactant and reaction product remains unchanged substantially, and various the intensity of spectral line also remain unchanged substantially; When etching began to weaken, the concentration of reaction product descended, and the intensity of spectral line sharply weakens; Until etching weakens after finish fully, the concentration of reaction product is zero.And the corresponding OES spectral line of etching reactant is when etching begins, because the etching reactant process that is etched consumes, its characteristic spectral line intensity can weaken rapidly, when etching begins to weaken, because the consumption of etching reactant reduces, the intensity of its characteristic spectral line will rise rapidly, after etching finishes fully, because etching reactant no longer is consumed, its characteristic spectral line can remain unchanged.
Consider the complexity of plasma etch process process, OES characteristic spectral line the intensity of spectral line under stable state of certain etching reactant or product is not absolute constant, because it is also relevant with structure and the situation of chamber.Generally speaking, the mean value of the intensity of the characteristic spectral line of a period of time is used as the fiducial value that etching terminal arranges in the whole stable state of employing etching.Yet in fact, the actual spectrum strength signal can be subject to the interference of a lot of environmental factors, and so steady unlike under the perfect condition.Such method can not be explained actual conditions fully, and inapplicable in some cases, can cause the misjudgment that etching process is changed.
Summary of the invention
The purpose of this invention is to provide a kind of endpoint monitoring method more sensitive and accurately plasma etch process.
For achieving the above object, the invention provides a kind of processing method of plasma etch process pilot signal, comprising:
According to the changing condition of signal strength signal intensity, with the change curve of real-time etching signal intensity of reflection plasma etching industrial be divided into initial period, stablize the stage of reaction, etching termination phase and etching finish the stage;
Mark the benchmark judging area in the described stable stage of reaction, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal point of described benchmark judging area and described etching termination phase;
Described benchmark judging area is divided into n time zone, obtains the mean value of etching signal intensity in each time zone, wherein n gets the integer greater than 1;
The fiducial value that maximum in all mean values or minimum value are judged as the etching terminal signal.
Optionally, described real-time etching signal is reactant in the described plasma etch process or the OES characteristic spectral line of product.
Optionally, described real-time etching signal is the differentiate value of the OES characteristic spectral line intensity of reactant in the described plasma etch process or product.
Optionally, the size of distance becomes positive correlation with the size of the etching error tolerances of the thickness of the rete that is etched between the starting point of the terminal point of described benchmark judging area and described etching termination phase.
Optionally, the etching signal of a plurality of reactants in the comprehensive described plasma etching industrial or product carries out described initial period, stablizes the stage of reaction, etching termination phase and etching finish the division in stage.
Optionally, the span of n is 3 to 10.
Optionally, n is 5.
Optionally, described time zone is the mutual zone that does not overlap continuously, and time of each zone experience is 1s ~ 2s.
The present invention also provides a kind of end-point control method of plasma etch process, comprising:
A plurality of wafers of same batch are provided;
Choose at least one wafer as sample, this sample is carried out plasma etching, and etching process is monitored, to obtain the change curve of real-time etching signal intensity;
Utilize aforesaid processing method that above-mentioned change curve is processed, obtain fiducial value;
Utilize the said reference value that the etching process of other wafer of same batch is carried out terminal point control.
Optionally, utilize the said reference value that the etching process of other wafer is carried out terminal point control, comprising: in the etching of other wafer, real-time testing etching signal intensity, when the deviation of the etching signal intensity level that records and described fiducial value exceeds a threshold value, finish etching.
Compared with prior art, the present invention has the following advantages:
The present invention is by marking benchmark judging area (time window) in the described stable stage of reaction, again described benchmark judging area is divided into n time zone (n is greater than 1), get the mean value of etching signal intensity in each time zone, obtain n mean value, maximum or the minimum value of then getting in the described n mean value are fiducial value, again the method that surpasses described fiducial value etching end variable quantity is used as etching terminal, method provided by the invention reflects the plasma etch process of being disturbed by various factors more accurately, and can be suitable for the needs of various different situations.
Description of drawings
Fig. 1 and Fig. 2 are the schematic diagrames of over time curve of the OES characteristic spectral line intensity of etching reactant among the embodiment one;
Fig. 3 is the derivative schematic diagram of curve over time of the OES characteristic spectral line intensity of etching reactant among the embodiment two.
Embodiment
For above-mentioned purpose of the present invention, feature and advantage can be become apparent more, below in conjunction with accompanying drawing the specific embodiment of the present invention is described in detail.
A lot of details have been set forth in the following description so that fully understand the present invention.But the present invention can implement much to be different from alternate manner described here, and those skilled in the art can do similar popularization in the situation of intension of the present invention, so the present invention is not subjected to the restriction of following public implementation.
The etching terminal of plasma etch process provided by the invention determines that method may further comprise the steps: same batch wafer is provided, the surface of described same batch of wafer has identical semiconductor device structure, and follow-up needs carry out identical plasma etch process; Get wherein at least a slice and put into plasma reaction chamber as sample and carry out plasma etching, and etching process is monitored, with the change curve of the OES characteristic spectral line intensity that obtains whole etching process; According to the change curve of the OES characteristic spectral line intensity that obtains analyze whole process (such as, divide the stages of etching: initial period, stablize the stage of reaction, termination phase), set rational etching terminal position according to the needs of technique; According to the etching terminal of setting the plasma etch process of other described same batch wafer is carried out etching terminal control.Wherein, the degree of the etching of each section representative on the change curve of the OES characteristic spectral line intensity of whole plasma etch process (such as initial period, stablize the stage of reaction etc.) can obtain corresponding checking by real-time physical verification (such as the thickness of judging tangent plane with ESEM) more here.
Wherein, on the change curve of OES characteristic spectral line intensity, the etching termination phase is a process, from the stable stage of reaction of etching technics OES characteristic spectral line Strength retention stably state finish again this section process in the middle of the held stationary of after etching finishes fully OES characteristic spectral line intensity, all calculate the etching termination phase.
And in the etching technics of actual production, must there be a definite point to be used as stopping the control signal of etching technics as etching terminal, can better control technique.Generally can be with the mean value of the intensity of spectral line of the whole stable stage of reaction as fiducial value, and with in the termination phase with the deviation of this fiducial value reach at first a certain threshold value (be empirical value, such as fiducial value 20%) point as etching terminal.
But this rigid evaluation of end point method can be ignored the difference of different demands in the reality, is difficult to guarantee best etching effect.Such as, guarantee that such as needs the rete of institute's etching is etched totally, even preferably can carry out over etching, just etching terminal need to be arranged in theory comparatively lean on after; And if need the rete of etching very thin, and try not to lower floor's injury, just need to arrange etching terminal forward.
For the demand, the present invention further provides a kind of definite method of fiducial value of the stable stage of reaction of plasma etching process, the situation the when fiducial value of seeking according to the method can represent that etching reaction is stablized accurately and can be suitable for the needs of various different situations.The method specifically comprises:
Obtain the real-time etching signal intensity in the plasma etching chamber;
According to the variation of signal strength signal intensity, with described plasma etching industrial be divided into initial period, stablize the stage of reaction, etching termination phase and etching finish the stage;
In the described stable stage of reaction, mark benchmark judging area (time window), described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal point of described benchmark judging area and described etching termination phase;
Described benchmark judging area is divided into n time zone (n is the integer greater than 1), gets the mean value of etching signal intensity in each time zone, obtain n mean value;
The fiducial value that maximum in n the mean value or minimum value are judged as the etching terminal signal.
Describe the said reference value in detail below by specific embodiment and determine method.
Embodiment one
Step S1: obtain the real-time etching signal intensity in the plasma etching chamber;
The described real-time etching signal that obtains can be the OES characteristic spectral line of the change in concentration situation of etching reactant or product in the reflection etch chamber.The variation of the intensity of certain reactant or the plasma of etching product or the light wave that the plasma group sends in the whole process of etching of carrying out in the intercepting plasma etching chamber.As adopt HBr/Cl
2In the reaction of etch polysilicon, can detecting reactant HBr or Cl
2Change in concentration, also can detect the change in concentration of volatility etching product SiCl.The signal of detecting reactant in the present embodiment obtains the situation of its variation shown in curve among Fig. 1.Wherein transverse axis is time T, and the longitudinal axis is OES characteristic spectral line intensity I v.
Those skilled in the art can be understood that, etching on whole wafer, not identical everywhere, even if be in stable etch stages at the film that is etched, reactor wall is sedimental to be generated or gradually release gradually, all can cause the slow variation of the intensity of OES characteristic spectral line under stable state.The factor that other are relevant with plasma reaction also all can change the intensity of OES characteristic spectral line.Show in the time dependent curve of OES characteristic spectral line intensity to be that near etching termination phase C place, the OES characteristic spectral line intensity of reactant raises gradually; After entering etching termination phase C, OES characteristic spectral line intensity is with faster amplitude rising; Finally, OES characteristic spectral line intensity tends to be steady, and indicates that etching finishes.
Step S2: according to the variation of signal strength signal intensity, with described plasma etching industrial be divided into initial period, stablize the stage of reaction, etching termination phase and etching finish the stage;
Continue with reference to shown in Figure 1, since zero point, along with the time changes, the curve of described representative etching signal has mainly experienced four-stage: the stage that sharply descends, change more gently but the once in a while stage of some fluctuation, the stage that gradually raises and stage of steadily no longer raising.They respectively corresponding initial period A, stablize stage of reaction B, etching termination phase C and etching is finished stage D.Wherein, the place of the boundary of initial period A and stable stage of reaction B for reducing suddenly near rate of change in that section curve that begins most, stablize between stage of reaction B and the etching termination phase C boundary for enter stablize stage of reaction B a period of time after, near suddenly larger transition place of generation of curve, the boundary that etching termination phase C and etching are finished stage D is the initial of last fully stably that section curve.In the reality, the reason such as too many or etching area is smaller owing to disturbing factor in the etching cavity, the etching signal impact that is interfered is larger, itself is fainter again simultaneously, the variation of curve is not too obvious, the boundary in these zones be not so obviously.Can detect the signal intensity of many kinds of substance in the described plasma etching reaction, obtain many curves, the variation tendency of weighing many curves considers the boundary that decides stages.Preferably, the many kinds of substance that detects can comprise etching reactant and etching product, because the variation of etching reactant and product roughly is opposite, especially near etching terminal, the place that can intersect with the change curve of the etching signal of etching reactant and etching product is as an important references point of boundary.
Step S3: in the described stable stage of reaction, mark benchmark judging area (Time window), described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal point of described benchmark judging area and described etching termination phase;
Because circumstance complication in the plasma reaction chamber, the concentration of etching reactant or product always has various variations in the stable state.The size that changes also is subjected to the fluctuation of instant environment and fluctuates.And etching signal is more weak, also is subject to easily the impact of other factors, and these other factorses are referred to as " noise ".The etching signal that obtains in the reality must be that fluctuation is constantly arranged, and just presents substantially certain trend, and is such as previously described, generally is used as fiducial value by trying to achieve mean value.Wherein, being averaging is a kind of method of anti-noise, because noise is occurrent, being averaging is that the impact of the chance of noise is loosened in the whole interval of averaging, thereby has reduced the fluctuation that noise causes, and gets rid of the interference of noise.
The method of this step can intercept the reactant OES characteristic spectral line intensity I v in a period of time interval of stablizing among the stage of reaction B again with reference to figure 2, and the zone that intercepts is as benchmark judging area (being designated as Time Window).The intercepting scope of Time Window is in the stable stage of reaction of plasma etch process, because present embodiment is to need to seek a fiducial value of judging etching terminal, described Time Window chooses preferably section start near etching termination phase C.General, the size of the error tolerances of the thickness of the size of distance L and the described rete that is etched is relevant between the starting point of the terminal point of described Time Window and described etching termination phase.The distance L of Time Window and terminal point is less than the etch period of the admissible error needs of thickness.
The time span of Time Window judges that according to the time span of concrete whole etching reaction process when noise effect was not very large, Time Window can get a little bit smaller, and when noise effect was very large, Time Window can get more greatly.Time Window accounts for 30% ~ 80% of the described stable stage of reaction and is advisable.Generally speaking, Time Window gets more than the 5s.If the etching reaction process is very long, can adaptively get the long time, can better represent the concentration of etching process reactant.
Step S4: described benchmark judging area is divided into n time zone (n is greater than 1), gets the mean value of etching signal intensity in each time zone, obtain n mean value;
According to the time span of Time Window of intercepting, adaptive Time Window is divided into n(n greater than 1) individual time zone, the numerical value of n is suitable can differentiate accurately being changed to of course of reaction.In the present embodiment, especially need to tell accurately the situation of change that gradually rises near etching terminal moment reaction substrate concentration.In addition, the n value is too large, and meeting is so that calculate lengthy and jumbledly, and deterministic process is too slow.Preferably, the n value is 5, then Time Window is divided into altogether five time zones of T1, T2, T3, T4 and T5.
According to the variation of the OES characteristic spectral line intensity I v in each time zone, obtain each regional mean value, obtain mean value I1, I2, I3, I4 and I5 corresponding in each time zone.
Step S5: get again n maximum or the fiducial value judged as the etching terminal signal of minimum value in the mean value.
Wherein getting which type of value selects according to the needs of concrete technology as the fiducial value of etching terminal signal judgement.As when in time controlling etching reaction at needs and stop, can selecting maximum as fiducial value, and when needing over etching to etch away fully with the material of guaranteeing to etch away, can select minimum value as fiducial value.Mode in the present embodiment can provide various selection to satisfy different technology controlling and process requirements.
As shown in Figure 2, I1, I2, I3, I4 and I5 increase successively, are maximum I5 near transition place of OES characteristic spectral line intensity curve among the figure wherein.Getting I5 is fiducial value, as the fiducial value of judging etching terminal.In other etching reaction, the disturbing factor that is subject to is different, and I1, I2, I3, I4 and I5 might not be the relations that increases successively, and it may be that other unexpected transition in value position except I5 becomes maximum.Such method and the mean value of the stabilization process of the whole etching of direct employing are that the method for fiducial value is compared, and can not cause misjudgment.If certain etching reaction is as described in the present embodiment, in its benchmark judging area in n time zone the etching signal average strength rise continuously, directly the maximum of selective etching signal strength signal intensity is as the fiducial value of etching terminal signal judgement.
In other execution mode, be the etching product such as the material that detects, in near etching terminal, the variation tendency of OES characteristic spectral line intensity curve reduces so, and the OES characteristic spectral line intensity of stablize stage of reaction after etching finishes is for zero or be close to zero.Under these circumstances, described fiducial value is got minimum value.
After obtaining the said reference value, can utilize described fiducial value to carry out the judgement of etching terminal.Concrete grammar is:
Step P1: obtain fiducial value according to aforesaid method, obtain reference value I 5;
Step P2: determine that etching finishes variable quantity;
Continue with reference to shown in Figure 2, by the analysis to curve, confirmable obtaining in the whole etching termination phase, it finishes the deviation of stage strength value and fiducial value the variation delta Iv(of etching reactant for etching).According to the needs of etching reaction, determine that etching finishes variation delta Iv', described Δ Iv' is less than Δ Iv.When needing etching terminal forward, described Δ Iv' can arrange smaller, need etching terminal to lean on after the time, described Δ Iv ' can arrange larger.
Step P3: the point that the deviation of setting etching signal intensity level and described fiducial value exceeds etching end variable quantity is described plasma etch process endpoint signal, and described plasma etch process terminal point is at described etching termination phase.
As shown in Figure 2, take I5 as fiducial value, the some S that the variable quantity of the etching reactant that detects reaches Δ Iv' is set as etching terminal.In follow-up technique, can control by etching terminal S the etching termination of the plasma etch process under the similarity condition.
Embodiment two
In the actual conditions, because circumstance complication in the plasma reaction chamber, the concentration of etching reactant or product always has various variations in the stable state.The size that changes also is subjected to the fluctuation of instant environment and fluctuates.Such as floating of temperature in the chamber, or chamber internal gas pressure the small situation such as float can cause that all etching reaction carries out the fluctuation of situation, thereby the concentration of etching reactant or product changes suddenly and rapidly, and rate of change also can have at short notice and fluctuates.But because etching signal is fainter, the amplitude of the variation that some little impact causes is also smaller, and directly the change curve with etching signal makes a decision more unintelligible.And disturb larger with respect to etching signal, directly can be bigger than normal as fiducial value with the mean value of the intensity of spectral line of the whole stable stage of reaction, can not show accurately the etching situation of stablizing the stage of reaction.And can some small variations be amplified by differentiate, and the minimum value place of differentiation can access the place of whole stable stage of reaction minimum interference.
Below be elaborated as an example of the characteristic spectral line intensity of measuring etching reactant example.
Step S1: obtain the real-time etching signal in the plasma etching chamber;
The derivative of the OES characteristic spectral line intensity of the final described etching reactant that obtains over time as shown in Figure 3, wherein transverse axis is time T, the longitudinal axis is the derivative Iv' of OES characteristic spectral line intensity.The derivative of OES characteristic spectral line intensity has reacted the situation of substances to be measured rate of change.
Step S2: according to the variation of signal strength signal intensity, with described plasma etching industrial be divided into initial period, stablize the stage of reaction, etching termination phase and etching finish the stage;
For present embodiment, those skilled in the art can be understood that etching reactant is very large at the rate of change of initial period, and is gradually slow, and namely the derivative of its OES characteristic spectral line intensity is also larger, then reduces gradually; Etching reactant is very little at the rate of change of stablizing the stage of reaction, and namely the size of the derivative of its OES characteristic spectral line intensity is close to zero, and fluctuation is arranged once in a while; Etching reactant begins to become large at the rate of change of etching termination phase, and gradually becomes large, and namely the derivative of its OES characteristic spectral line intensity begins to increase; Etching reactant can not become in the etching stage of finishing again, and namely the derivative of its OES characteristic spectral line intensity is zero.Situation in the similar embodiment one, the curve that previous step is obtained are divided into initial period A, stablize stage of reaction B, etching termination phase C and etching are finished the stage (not shown).
Step S3: the situation in the similar embodiment one, in the described stable stage of reaction, mark benchmark judging area (Time window), described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal point of described benchmark judging area and described etching termination phase;
Step S4: described benchmark judging area is divided into n time zone (n is greater than 1), gets the mean value of etching signal intensity in each time zone, obtain n mean value;
Similar with embodiment one, Time Window is divided into altogether five time zones of T1, T2, T3, T4 and T5, obtain each regional mean value, obtain mean value I1, I2, I3, I4 and I5 corresponding in each time zone.
Step S5: the fiducial value that the maximum in n the mean value or minimum value are judged as the etching terminal signal.
As previously mentioned, in such situation, the mean value of whole Time window comes can be bigger than normal as fiducial value.In stable state, optimal situation can be that etching reaction is interference-free in the whole stable state, and then the concentration of etching reactant or product does not change, and the derivative Iv' of OES characteristic spectral line intensity should be zero.And in the reality, etching reaction is kept away unavoidably disturbed.Select as much as possible the place of rate of change minimum, more near original perfect condition.Therefore be fit to get minimum value in the several values of I1, I2, I3, I4 and I5 as fiducial value.
Similar with embodiment one, after the acquisition said reference value, can utilize described fiducial value to carry out the judgement of etching terminal.
Embodiment three
In the present embodiment, the stable stage of reaction time of described plasma etch process is very short, described etching reaction substrate concentration reduces suddenly when etching begins also enough not to be stablized described etching and has just finished, and described etching reaction substrate concentration has begun again unexpected rising.For such situation, described when carrying out the division of benchmark judging area (Time window), its starting point might be displaced to initial period or etching termination phase or/and terminal point is difficult to guarantee to be in fully to stablize in the stage of reaction.And described benchmark judging area is generally greater than 5s.When time of described stable stage of reaction time during less than or equal to 6 seconds, the beginning or end of the fiducial value judging area of getting surpasses the beginning or end of stablizing the stage of reaction easily.In similar above-mentioned situation, the etching reactant concentration ratio actual conditions of closing in the time zone of beginning or end are higher.Under these circumstances, directly getting the minimum value in the benchmark judging area, can be near the value of the truth of etching reaction.
General, when time of described stable stage of reaction time during less than or equal to 6 seconds, directly the minimum value of selective etching signal strength signal intensity is as the fiducial value of etching terminal signal judgement.
Similar with embodiment one, after the acquisition said reference value, can utilize described fiducial value to carry out the judgement of etching terminal.
The above only is preferred embodiment of the present invention, is not the present invention is done any pro forma restriction.
Although the present invention discloses as above with preferred embodiment, yet is not to limit the present invention.Any those of ordinary skill in the art, do not breaking away from the technical solution of the present invention scope situation, all can utilize method and the technology contents of above-mentioned announcement that technical solution of the present invention is made many possible changes and modification, or be revised as the equivalent embodiment of equivalent variations.Therefore, every content that does not break away from technical solution of the present invention according to any simple modification, equivalent variations and the modification that technical spirit of the present invention is done above embodiment, all still belongs in the scope of technical solution of the present invention protection.
Claims (12)
1. the processing method of a plasma etch process pilot signal is characterized in that, comprising:
According to the changing condition of signal strength signal intensity, with the change curve of real-time etching signal intensity of reflection plasma etching industrial be divided into initial period, stablize the stage of reaction, etching termination phase and etching finish the stage;
Mark the benchmark judging area in the described stable stage of reaction, described benchmark judging area accounts for 30% ~ 80% of the described stable stage of reaction, and has certain distance between the starting point of the terminal point of described benchmark judging area and described etching termination phase;
Described benchmark judging area is divided into n time zone, obtains the mean value of etching signal intensity in each time zone, wherein n gets the integer greater than 1;
The fiducial value that maximum in all mean values or minimum value are judged as the etching terminal signal.
2. processing method as claimed in claim 1 is characterized in that, described real-time etching signal is reactant in the described plasma etch process or the OES characteristic spectral line of product.
3. processing method as claimed in claim 1 is characterized in that, described real-time etching signal is the differentiate value of the OES characteristic spectral line intensity of reactant in the described plasma etch process or product.
4. processing method as claimed in claim 1 is characterized in that, the size of distance becomes positive correlation with the size of the etching error tolerances of the thickness of the rete that is etched between the starting point of the terminal point of described benchmark judging area and described etching termination phase.
5. processing method as claimed in claim 1, it is characterized in that a plurality of reactants in the comprehensive described plasma etching industrial or the etching signal of product carry out described initial period, stablize the stage of reaction, etching termination phase and etching are finished the division in stage.
6. processing method as claimed in claim 1 is characterized in that, the span of n is 3 to 10.
7. processing method as claimed in claim 6 is characterized in that, n is 5.
8. processing method as claimed in claim 1 is characterized in that, described time zone is the mutual zone that does not overlap continuously, and time of each zone experience is 1s ~ 2s.
9. processing method as claimed in claim 1 is characterized in that, when n the interior etching signal average strength of time zone rises continuously in the described benchmark judging area, and the fiducial value that the maximum of selective etching signal strength signal intensity is judged as the etching terminal signal.
10. processing method as claimed in claim 1 is characterized in that, the time of described benchmark judging area is during less than or equal to 6 seconds, the fiducial value that the minimum value of selective etching signal strength signal intensity is judged as the etching terminal signal.
11. the end-point control method of a plasma etch process is characterized in that, comprising:
A plurality of wafers of same batch are provided;
Choose at least one wafer as sample, this sample is carried out plasma etching, and etching process is monitored, to obtain the change curve of real-time etching signal intensity;
Utilize and such as each described processing method in the claim 1 to 10 above-mentioned change curve is processed, obtain fiducial value;
Utilize the said reference value that the etching process of other wafer of same batch is carried out terminal point control.
12. end-point control method as claimed in claim 11, it is characterized in that, the step of utilizing the said reference value that the etching process of other wafer is carried out terminal point control comprises: in the etching of other wafer, real-time testing etching signal intensity, when the deviation of the etching signal intensity level that records and described fiducial value exceeds a threshold value, finish etching.
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| CN103400803A (en) * | 2013-07-24 | 2013-11-20 | 上海宏力半导体制造有限公司 | Formation method of flash memory storage unit |
| CN105097589A (en) * | 2015-05-27 | 2015-11-25 | 上海华力微电子有限公司 | Method for detecting over-etching amount of metal hard mask all-in-one etching through hole |
| CN110246743A (en) * | 2014-10-20 | 2019-09-17 | 朗姆研究公司 | The system and method for detection processing point in multi-mode pulse processing |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103400803A (en) * | 2013-07-24 | 2013-11-20 | 上海宏力半导体制造有限公司 | Formation method of flash memory storage unit |
| CN103400803B (en) * | 2013-07-24 | 2016-06-01 | 上海华虹宏力半导体制造有限公司 | The forming method of flash memory cell |
| CN110246743A (en) * | 2014-10-20 | 2019-09-17 | 朗姆研究公司 | The system and method for detection processing point in multi-mode pulse processing |
| CN105097589A (en) * | 2015-05-27 | 2015-11-25 | 上海华力微电子有限公司 | Method for detecting over-etching amount of metal hard mask all-in-one etching through hole |
| CN105097589B (en) * | 2015-05-27 | 2018-08-28 | 上海华力微电子有限公司 | A kind of detection method of metal hardmask integration etching through hole over etching amount |
Also Published As
| Publication number | Publication date |
|---|---|
| TWI471933B (en) | 2015-02-01 |
| TW201417169A (en) | 2014-05-01 |
| CN102931045B (en) | 2015-08-26 |
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