CN102799793B - Method and equipment for calculating chemical mechanical polishing removal rate - Google Patents
Method and equipment for calculating chemical mechanical polishing removal rate Download PDFInfo
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- CN102799793B CN102799793B CN201210301195.4A CN201210301195A CN102799793B CN 102799793 B CN102799793 B CN 102799793B CN 201210301195 A CN201210301195 A CN 201210301195A CN 102799793 B CN102799793 B CN 102799793B
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- 238000000034 method Methods 0.000 title claims abstract description 106
- 238000005498 polishing Methods 0.000 title claims abstract description 55
- 239000000126 substance Substances 0.000 title abstract description 6
- 238000000227 grinding Methods 0.000 claims abstract description 209
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- 239000007788 liquid Substances 0.000 claims abstract description 59
- 230000008569 process Effects 0.000 claims abstract description 54
- 238000004364 calculation method Methods 0.000 claims abstract description 29
- 238000004458 analytical method Methods 0.000 claims abstract description 25
- 239000006061 abrasive grain Substances 0.000 claims description 23
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- 238000010790 dilution Methods 0.000 claims description 14
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- 238000006243 chemical reaction Methods 0.000 claims description 12
- 239000000463 material Substances 0.000 claims description 12
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- 238000012546 transfer Methods 0.000 claims description 6
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- 238000005259 measurement Methods 0.000 claims description 5
- 238000012986 modification Methods 0.000 claims description 4
- 230000004048 modification Effects 0.000 claims description 4
- 238000005457 optimization Methods 0.000 claims description 4
- 229910052751 metal Inorganic materials 0.000 claims description 3
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- 230000004888 barrier function Effects 0.000 claims description 2
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- 238000004448 titration Methods 0.000 claims description 2
- 238000012876 topography Methods 0.000 claims description 2
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- 238000005516 engineering process Methods 0.000 description 3
- 230000003628 erosive effect Effects 0.000 description 3
- 239000004411 aluminium Substances 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 230000002925 chemical effect Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
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Abstract
A method for calculating the removal rate of chemical mechanical polishing is provided, which comprises the following steps: determining a grinding removal rate calculation formula MRR which is kPV; analyzing factors influencing the grinding removal rate to obtain a function equation of the factors influencing the grinding removal rate; and substituting the function equation of the factors into the MRR (total molar ratio) kPV to obtain a specific calculation formula of the grinding removal rate, and calculating the grinding removal rate MRR according to the specific calculation formula. In addition, a device for calculating the chemical mechanical polishing removal rate is also provided. According to the scheme provided by the invention, by analyzing the factors influencing the grinding removal rate and comprehensively considering the interaction relation among the wafer, the particles, the grinding pad and the grinding liquid, the interaction rule among multiple bodies is deeply disclosed, the process reality of chemical mechanical grinding can be more objectively and truly described, and the method has a positive guiding effect on the mechanism analysis of CMP, the layout design and the process research and development of a large production line.
Description
Technical field
The present invention relates to CMP manufacturing process and CMP modeling technique field, specifically, the present invention relates to the method and apparatus that cmp clearance calculates.
Background technology
Cmp (CMP, ChemicalMechanicalPolishing) as the key link of manufacturability design technical solutions, be the hyperfine process technology that uniquely can realize global planarizartion in current VLSI (very large scale integrated circuit) manufacture, be now widely used in the leveling on the surface such as integrated circuit (IC) chip, micromachine.
High-k gate dielectric and metal gate technique (HKMG, High-kMetalGate) make Moore's Law be continued in 45/32 nanometer nodes.Current HKMG technique has two kinds of main flow integrated schemes, is " first grid " and " post tensioned unbonded prestressed concrete " respectively." post tensioned unbonded prestressed concrete " is also called replaceable grid (hereinafter referred to as RMG), and when using this technique, high-k gate dielectric is without the need to through high-temperature step, and the reliability of chip is higher.Therefore industry is more prone to when manufacturing high performance chips select RMG technique.But RMG technological process relates to more processing step, face more technique difficulty and design restriction, flatness is extremely difficult up to standard.
Grinding clearance (MRR, MaterialRemovalRate) as the important indicator describing chip surface height change speed, the emphasis of extensive concern and research is become in the model Analysis on Mechanism of CMP, once obtain MRR, the instantaneous height change calculating grinding chip surface can be used it for further, provide real time profile and the feature of chip surface, and result of calculation can be used for the application flow such as layout design, Analysis of Electrical Characteristics, therefore, how to obtain and grind the key factor that clearance computing formula becomes CMP model Analysis on Mechanism accurately and reliably.
At present, because the process of cmp is very complicated, the process control of CMP still rests on the experience real example stage, alone a kind of model or means are difficult to the real interaction rule disclosed between grinding composition, obtain and accurately reasonably grind clearance formula, the existing analysis about various chemical factor is general all only qualitative or be semi-quantitatively explained and illustrated the data of experiment measuring to a certain extent, therefore, only have the various procedure parameters to CMP, contact form between grinding interface and the fluid situation of lapping liquid are analysed in depth, fully could disclose the grinding mechanism of CMP, constantly meet the integrated circuit fabrication process demand of develop rapidly.
Clearance formula is ground in order to obtain a CMP rationally describing chemistry, machinery and hydrodynamic effect, the present invention considers polishing particles and grinding pad and to contact chip and noncontact is stressed, lapping liquid is on multiple impacts such as the chemical effect of chip, the flow condition of lapping liquid and ambient temperatures, angularly chip surface is removed from grinding pad, polishing particles, lapping liquid, chip, ambient temperature and technique and carry out comprehensive portraying, obtain the disposal route of the chip surface grinding removal with broad applicability.Generally speaking, it is the empirical Preston equation adopting glass polishing industry conventional: MRR=kPV that domestic and international project application solves the more common method of grinding clearance, wherein, V is the relative sliding speed (the relative sliding distance in the unit interval) between chip and grinding pad, P is the external pressure putting on chip surface, k is Preston coefficient, and generally in the application of CMP, other various factors embody mainly through coefficient k.But which factor k specifically depends on, and there is no final conclusion so far, how k is resolved to and more rationally effectively comprise chemistry, machinery, the isoparametric function of fluid, the Analysis on Mechanism no matter to CMP, or all there is great importance to the process exploitation of CMP.
Therefore, be necessary to propose effective technical scheme, to solve the problem that cmp clearance calculates.
Summary of the invention
Object of the present invention is intended at least solve one of above-mentioned technological deficiency, particularly by analyzing each factor of grinding clearance, optimizes the calculating of grinding clearance.
The embodiment of the present invention proposes a kind of method that cmp clearance calculates on the one hand, comprises the following steps:
Determine grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient;
The factor of analyzing influence grinding clearance, obtains the functional equation affecting factor described in grinding clearance;
The functional equation of described factor is substituted in MRR=kPV, obtains the specific formula for calculation grinding clearance, calculate grinding clearance MRR according to described specific formula for calculation.
The embodiment of the present invention also proposed the equipment that a kind of cmp clearance calculates on the other hand, comprises and selects module, analysis module and computing module.
Described selection module, for selected grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient;
Described analysis module, for the factor of analyzing influence grinding clearance, obtains the functional equation affecting factor described in grinding clearance;
Described computing module, for being substituted in MRR=kPV by the functional equation of described factor, obtains the specific formula for calculation grinding clearance, calculates grinding clearance MRR according to described specific formula for calculation.
The embodiment of the present invention also proposed surface topography acquisition methods in a kind of cmp simulation process on the other hand, comprising:
According to grinding clearance influence factor in the influential factor of Process configuration, the Process configuration of adjustment cmp, wherein, one or more in the quality transmission rate that the influence factor of described grinding clearance comprises effective abrasive grains subnumber in lapping liquid, single-particle removes volume, thing is removed in process of lapping parameter, chip surface grinding, lapping liquid pH value and temperature;
According to the Process configuration of the described cmp of adjustment, in conjunction with actual process measurement result, matching is carried out to determine final technological parameter to grinding clearance test figure;
Described final technological parameter is used for cmp analog simulation, to obtain chip surface morphology change.
The such scheme that the present invention proposes, by investigating Preston equation: MRR=kPV, grinding coefficient k is progressively resolved, the factor of analyzing influence grinding clearance, considers wafer, particle, grinding pad and lapping liquid limbs interaction relationship, action rule between deep announcement many bodies, more the technique reality of cmp can be described objective reality ground, to the Analysis on Mechanism of CMP, layout design, and large production-line technique research and development have positive directive function.
The aspect that the present invention adds and advantage will part provide in the following description, and part will become obvious from the following description, or be recognized by practice of the present invention.
Accompanying drawing explanation
The present invention above-mentioned and/or additional aspect and advantage will become obvious and easy understand from the following description of the accompanying drawings of embodiments, wherein:
Fig. 1 is the method flow diagram that embodiment of the present invention cmp clearance calculates;
Fig. 2 is for grinding clearance analysis of Influential Factors and optimize calculating schematic diagram;
Fig. 3 is polishing particles and grinding pad interaction schematic diagram;
Fig. 4 is the stressed schematic diagram of polishing particles;
Fig. 5 is the apparatus structure schematic diagram that embodiment of the present invention cmp clearance calculates;
Fig. 6 is the optimization Simulation process flow diagram to HKMGAlCMP technique.
Embodiment
Be described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Being exemplary below by the embodiment be described with reference to the drawings, only for explaining the present invention, and can not limitation of the present invention being interpreted as.
Clearance is ground in order to obtain a CMP rationally describing chemistry, machinery and hydrodynamic effect, the present invention considers polishing particles and grinding pad and to contact chip and noncontact is stressed, lapping liquid is on multiple impacts such as the chemical effect of chip, the flow condition of lapping liquid and ambient temperatures, angularly chip surface is removed from grinding pad, polishing particles, lapping liquid, chip, ambient temperature and technique and carry out comprehensive portraying, obtain the disposal route of the chip surface grinding removal with broad applicability.
Embodiment one
Based on above-mentioned purpose, the present invention proposes a kind of method that cmp clearance calculates, comprise the following steps:
Determine grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient;
The factor of analyzing influence grinding clearance, obtains the functional equation affecting factor described in grinding clearance;
The functional equation of described factor is substituted in MRR=kPV, obtains the specific formula for calculation grinding clearance, calculate grinding clearance MRR according to described specific formula for calculation.
As shown in Figure 1, be the method flow diagram that embodiment of the present invention cmp clearance calculates, comprise the following steps:
S110: determine grinding clearance computing formula.
In step s 110, first determine grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient.
Generally speaking, domestic and international project application solves the more common method of grinding clearance is the empirical Preston equation adopting glass polishing industry conventional: MRR=kPV.General in the application of CMP, other various factors embody mainly through coefficient k.But which factor k specifically depends on, and there is no final conclusion so far, how k is resolved to and more rationally effectively comprise chemistry, machinery, the isoparametric function of fluid, the Analysis on Mechanism no matter to CMP, or all there is great importance to the process exploitation of CMP.The scheme that the present invention proposes, makes a concrete analysis of on the factor of impact grinding clearance, and draws feasible numerical procedure.
S120: the factor of analyzing influence grinding clearance.
In the step s 120, the factor of analyzing influence grinding clearance, obtains the functional equation affecting grinding clearance factor.
As embodiments of the invention, influence factor comprises following one or more factor:
Effective abrasive grains subnumber in lapping liquid, single-particle removal volume, process of lapping parameter, chip surface grind quality transmission rate, lapping liquid pH value and the temperature of removing thing.Resolving as shown in Figure 2, can learn further, the determination of effective abrasive grains subnumber can consider that many factors comprehensively draws, single-particle removes volume can derive from solving of equilibrium equation, process of lapping parameter comprises the sliding speed of the local pressure grinding pad relative to chip between grinding pad with chip, in the temperature that lapping liquid pH value and temperature derive from measuring and pH value.
As shown in Figure 2, for grinding clearance analysis of Influential Factors and optimization calculate schematic diagram.Specifically, influence factor is summarized as follows:
determine the effective abrasive grains subnumber in lapping liquid, such as, comprise following process:
(1) investigate the touching act between polishing particles and grinding pad, abrasive grains subnumber N is split as effective polishing particles N
ewith invalid polishing particles N
inumber, effective polishing particles is the polishing particles directly having contacted abrasive action with chip, invalid polishing particles is that grinding pad does not directly contact with chip, thus to the inoperative polishing particles of grinding, is really effective abrasive grains subnumber N to grinding clearance active
e, as shown in Figure 3;
(2) Greenwood and Williamson Elastic Contact model [1] is utilized, the real contact area of computing chip and grinding pad
wherein, A is chip area, η grinding pad rough peak density,
for coarse summit radius, d is the distance between chip surface and grinding pad average peak height, and z is grinding pad surface elevation,
σ is the standard deviation of peak height;
(3) putative molecule structure is the orderly distribution of stratiform, obtains the effective molecular number participating in grinding and remove
wherein, c
vfor polishing particles volumetric concentration, V
ait is abrasive grain volume;
(4) according to the research work [2] of Jeng, the effective molecular number participating in grinding removal is determined
wherein, d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, ρ
afor the density of polishing particles, D is the mean diameter of abrasive particle;
(5) to Effective grains' number N
e1and N
e2get weighted mean, obtain final effectively abrasive grains subnumber N=β N
e1+ (1-β) N
e2, wherein β is weight coefficient, 0≤β≤1.
determining that single-particle removes volume, namely embedding chip depth delta H by investigating effective polishing particles 1 with mill mutual relationship between the suffered load of grain, establishes single effective polishing particles and removes having of chip surface material effect volume Vol s , such as, comprise following process:
(1) carry out force analysis to polishing particles, schematic diagram as shown in Figure 4.According to force balance principle, chip contact force F suffered by abrasive particle
w, suffered grinding pad contact force F
pand meet F between model ylid bloom action power
p+ F
vdw=F
w;
(2) above micro object balance equation F is solved
p+ F
vdw=F
w, polishing particles can be obtained and embed chip depth delta H
1;
(3) the active volume Vol that single effective polishing particles removes chip surface material is established
s=K
1v Δ S (R
a, Δ H
1), wherein K
1for proportionality constant, Δ S is the black bow-shaped area in Fig. 4, and V is the sliding speed of the relative grinding pad of chip.
the impact of local pressure P in procedure parameter:
From Preston equation: MRR=kPV, when other conditions are fixing, the local pressure P between grinding pad and chip is linear with grinding clearance, such as, need not resolve P value herein.
the impact of temperature T, pH value n:
Can confirm by experiment, grind clearance and between temperature T, pH value n, there is following dependence:
wherein, R is universal gas constant, E
afor energy of activation.
the impact of the quality transmission rate of grinding product:
According to the flow performance of lapping liquid, the investigation transfer rate of grinding product, the funtcional relationship between mass density and MRR are: MRR ∝ ρ
wυ, ρ
wfor reaction product density, υ is the quality transmission rate that reactant enters chip surface and reaction product and departs from chip surface, can be obtained by efficiency frontier shelf theory:
wherein, K is chemical reaction equilibrium constant, k
efor chemical reaction rate, C
i, C
iIfor lapping liquid interface and chip surface interfacial oxide film concentration, β
i, β
iIfor mass transfer coefficient.
S130: the factor according to impact grinding clearance calculates grinding clearance.
In step s 130, which, the functional equation of described factor is substituted in MRR=kPV, obtain the specific formula for calculation grinding clearance, calculate grinding clearance MRR according to described specific formula for calculation
Such as, as embodiments of the invention, based on above analysis, the pass of grinding between the density of clearance and local pressure, effectively abrasive grains subnumber, quality transmission rate, chip surface material, lapping liquid pH value and temperature is:
The such scheme that the present invention proposes, by investigating Preston equation: MRR=kPV, grinding coefficient k is progressively resolved, the factor of analyzing influence grinding clearance, considers wafer, particle, grinding pad and lapping liquid limbs interaction relationship, action rule between deep announcement many bodies, more the technique reality of cmp can be described objective reality ground, to the Analysis on Mechanism of CMP, layout design, and large production-line technique research and development have positive directive function.The embodiment of the present invention is applicable to the calculating of the cmp clearance of aluminium in HKMG technique.
Embodiment two
Corresponding to the method for above-mentioned calculating, as shown in Figure 5, the embodiment of the present invention also proposed the equipment 500 that a kind of cmp clearance calculates, and comprises and selects module 510, analysis module 520 and computing module 530.
Specifically, select module 510 for selected grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient.
Analysis module 520, for the factor of analyzing influence grinding clearance, obtains the functional equation affecting grinding clearance factor.
The factor that analysis module 520 is analyzed comprises following one or more factor:
Effective abrasive grains subnumber in lapping liquid, single-particle removal volume, process of lapping parameter, chip surface grind quality transmission rate, lapping liquid pH value and the temperature of removing thing.
The functional equation that effective abrasive grains subnumber calculates is:
Effective abrasive grains subnumber N=β N
e1+ (1-β) N
e2,
Wherein, 0≤β≤1;
a is chip area, η grinding pad rough peak density,
for coarse summit radius, d is the distance between chip surface and grinding pad average peak height, and z is grinding pad surface elevation,
σ is the standard deviation of peak height; c
vfor polishing particles volumetric concentration, V
ait is abrasive grain volume;
d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, ρ
afor the density of polishing particles, D is the mean diameter of abrasive particle.
The density of quality transmission rate and chip surface material with the pass of grinding clearance MRR is:
MRR ∝ ρ
wυ, ρ
wfor the density of chip surface material, υ is quality transmission rate.
The pass of lapping liquid pH value and temperature and grinding clearance MRR is:
wherein, T is temperature, n is pH value, and R is universal gas constant, E
afor energy of activation.
Computing module 530, for being substituted in MRR=kPV by the functional equation of described factor, obtains the specific formula for calculation grinding clearance, calculates grinding clearance MRR according to specific formula for calculation.
Specifically, the specific formula for calculation of computing module 530 calculating grinding clearance MRR is:
Wherein, wherein K
1, K
2for proportionality constant, Δ S is that polishing particles embeds chip portion cross-sectional area, and V is the sliding speed of the relative grinding pad of chip, and K is chemical reaction equilibrium constant, k
efor chemical reaction rate, C
i, C
iIfor lapping liquid interface and chip surface interfacial oxide film concentration, β
i, β
iIfor mass transfer coefficient, P is the local pressure between grinding pad and chip, Δ H
1for polishing particles embeds the degree of depth of chip, R
afor polishing particles radius.
Embodiment three
In order to explain the present invention and the embody rule based on above method or equipment further, provide embody rule case below, a kind of method obtaining cmp surface grinding situation, as shown in Figure 6, such as concrete operations scheme is as follows for process flow diagram:
step 1: consider, to the influential factor of Process configuration in the influence factor of grinding clearance, to adjust
the Process configuration of whole cmp
The influence factor of described grinding clearance as previously mentioned, comprises the effective abrasive grains subnumber in lapping liquid, single-particle removes volume, process of lapping parameter, chip surface grinding remove the quality transmission rate of thing, lapping liquid pH value and temperature.
This step specifically comprises:
(1) the influence factor calculating of above grinding clearance is converted to Accounting Legend Code module, develop a set of simulation softward calculating grinding clearance, this software is made to have following emulation module: effectively polishing particles configuration module, parameters of technique process configuration module, quality transmission rate module and temperature, pH value adjustment module, wherein, described effective polishing particles configuration module comprises grinding pad chooser module and lapping liquid parameter allotment submodule.Each module is run step S120 in reference example one and analyzed, and repeats no more herein, and removes bulk factor for the influential single-particle of grinding clearance, because this factor and Process configuration onrelevant, therefore can select not to be this factor configuration code module.
(2) according to temperature PH adjustment module result of calculation reflect about grinding clearance temperature variant Function feature, choose the working temperature being suitable for grinding; Add deionized water to lapping liquid, adjustment pH value, Binding experiment measures the microcosmic grinding state of chip surface, chooses the pH value being conducive to CMP, and the pH value such as chosen meets maximum grinding and removes speed;
(3) according to the funtcional relationship changed with polishing particles feature (mean diameter, concentration, density) about grinding clearance that lapping liquid parameter allotment submodule result of calculation reflects, choose polishing particles, the polishing particles such as chosen meets maximum grinding and removes speed;
(4) further, also according to lapping liquid parameter allotment submodule result of calculation reflect about the Function feature of grinding clearance with lapping liquid density, concentration change, according to concrete technology configuration requirement, select other components of lapping liquid, the lapping liquid composition such as selected meets maximum grinding and removes speed;
(5) according to grinding pad chooser module result of calculation reflect about grinding clearance with the Function feature of grinding pad rough peak changes in distribution, Binding experiment measures the microcosmic grinding state of chip surface, according to features such as surface dish and erosions, choose a kind of grinding pad being suitable for CMP and removing, and according to actual process situation, grinding pad is revised, to keep the stable grinding efficiency of grinding pad;
(6) according to the funtcional relationship changed with lapping liquid flowing about grinding clearance that quality transmission rate module result of calculation reflects, according to defects such as surface corrosions, regulate the titration speed of lapping liquid, to control the chemical reaction course of lapping liquid oxygenant at chip surface, thus keep homogeneity and the stability of grinding technics;
(7) according to the Function feature changed with process of lapping parameter (pressure, rotating speed etc.) about grinding clearance that parameters of technique process configuration module result of calculation reflects, Binding experiment measures the microcosmic grinding state of chip surface, according to features such as surface dish and erosions, adjustment working pressure and chip, grinding pad rotating speed;
(8) combine the result of calculation of (1)-(7), comprehensive selection is suitable for the Process configuration of CMP.
step 2: optimize and demarcate technological parameter
According to the technical recipe that step 1 adjusts, in conjunction with actual process measurement result, numerical fitting is carried out to grinding clearance test figure, such as, can adopt non-linear least square method, determine the model parameter that parsing k value relies on; By measuring test figure further, can successive optimization model parameter, finally adjust a set of technological parameter being suitable for cmp.
step 3: chip surface morphology emulation and real-time estimate
By reading chip surface elemental height, rate equation is removed in conjunction with new grinding of resolving, the technological parameter that step 2 obtains is directly used in the CMP analog simulation under stabilization process condition, can detecting real-time chip surface pattern change, reflection metal and restraining barrier, difference in height between dielectric layer, the graphic feature of chip grinding flatness is portrayed in Dynamic profiling butterfly and erosion etc.
step 4: focus reactionary slogan, anti-communist poster and Analysis of Electrical Characteristics
According to butterfly emulated data, whether can show and demarcate the hot spot region of design layout, investigate lapped face flatness and meet the requirements, overproof abnormity point will be marked, and as required can reactionary slogan, anti-communist poster in the display of original domain, allow its abnormal cause of deviser's observation analysis.In addition, aluminium thickness profile data can also provide initial input for parasitic parameter extraction and Analysis of Electrical Characteristics, for the manufacturability design of process oriented provides decision references.
The such scheme that the present invention proposes, by investigating Preston equation: MRR=kPV, grinding coefficient k is progressively resolved, consider wafer, particle, grinding pad and lapping liquid limbs interaction relationship, action rule between deep announcement many bodies, the mean diameter of grinding clearance and polishing particles can be obtained, concentration, density, the density of lapping liquid, concentration, grinding chip hardness, elastic modulus, the rough peak distribution of grinding pad, the flow performance of lapping liquid, funtcional relationship between the factors such as process of lapping parameter and grinding temperature, more the technique reality of cmp can be described objective reality ground, to the Analysis on Mechanism of CMP, layout design, and large production-line technique research and development have positive directive function.Along with the reduction of process node, because various microeffect constantly occurs, chemistry and fluid matasomatism grinding remove in importance and functions more outstanding, especially the technical process control of CMP still rests on the experience real example stage, and people understand abundant not enough on lapping liquid chemical property on reaction mechanisms such as the impacts of various parameter.Therefore, the k value analytic model that the present invention proposes, has more realistic meaning to the CMP flow process exploitation of 32 nanometer nodes following high K gate dielectric-metallic grid especially.
Although describe in detail about example embodiment and advantage thereof, being to be understood that when not departing from the protection domain of spirit of the present invention and claims restriction, various change, substitutions and modifications can being carried out to these embodiments.For other examples, those of ordinary skill in the art should easy understand maintenance scope in while, the order of processing step can change.
In addition, range of application of the present invention is not limited to the technique of the specific embodiment described in instructions, mechanism, manufacture, material composition, means, method and step.From disclosure of the present invention, to easily understand as those of ordinary skill in the art, for the technique existed at present or be about to develop, mechanism, manufacture, material composition, means, method or step later, wherein their perform the identical function of the corresponding embodiment cardinal principle that describes with the present invention or obtain the identical result of cardinal principle, can apply according to the present invention to them.
Therefore, claims of the present invention are intended to these technique, mechanism, manufacture, material composition, means, method or step to be included in its protection domain.It should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention, can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
List of references:
[1]J.A.Greenwood,J.B.P.Williamson,ContactofnominallyflatsurfaceProc.R.Soc.(London),Ser.A295(1996)300–319.
[2]JengYR，HuangPY.Amaterialremovalratemodelconsideringinterfacialmicro-contactwearbehaviorforchemicalmechanicalpolishing[J].JTribol，20()5，127(l):190-197.
Claims (10)
1. a method for cmp clearance calculating, is characterized in that, comprise the following steps:
Determine grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient;
The factor of analyzing influence grinding clearance, obtain the functional equation affecting factor described in grinding clearance, described factor comprises following factor: the effective abrasive grains subnumber in lapping liquid, single-particle removal volume, process of lapping parameter, chip surface grind quality transmission rate, lapping liquid pH value and the temperature of removing thing;
Described process of lapping parameter comprises the sliding speed of the local pressure grinding pad relative to chip between grinding pad with chip;
The functional equation of described factor is substituted in MRR=kPV, obtains the specific formula for calculation grinding clearance, calculate grinding clearance MRR according to described specific formula for calculation;
The specific formula for calculation of described grinding clearance is:
Wherein, wherein K
1, K
2for proportionality constant, Δ S is that polishing particles embeds chip portion cross-sectional area, and V is the sliding speed of the relative grinding pad of chip, and K is chemical reaction equilibrium constant, k
efor chemical reaction rate, C
i, C
iIfor lapping liquid interface and chip surface interfacial oxide film concentration, β
i, β
iIfor mass transfer coefficient, P is the local pressure between grinding pad and chip, Δ H
1for polishing particles embeds the degree of depth of chip, R
afor polishing particles radius, A is chip area, η grinding pad rough peak density,
for coarse summit radius, z is grinding pad surface elevation,
d is the distance between chip surface and grinding pad average peak height, and β is weight coefficient, 0≤β≤1, c
vfor polishing particles volumetric concentration, ρ
wfor reaction product density, ρ
afor the density of polishing particles, σ is the standard deviation of peak height, d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, D is the mean diameter of abrasive particle, and R is universal gas constant, E
afor energy of activation, n is pH value.
2. the method for claim 1, is characterized in that, the functional equation calculating described effective abrasive grains subnumber is:
Effective abrasive grains subnumber N=β N
e1+ (1-β) N
e2,
Wherein, 0≤β≤1;
a is chip area, η grinding pad rough peak density,
for coarse summit radius, d is the distance between chip surface and grinding pad average peak height, and z is grinding pad surface elevation,
σ is the standard deviation of peak height; c
vfor polishing particles volumetric concentration, V
ait is abrasive grain volume;
d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, ρ
afor the density of polishing particles, D is the mean diameter of abrasive particle.
3. the method for claim 1, is characterized in that, the density of described quality transmission rate and chip surface material with the pass of grinding clearance MRR is:
MRR ∝ ρ
wυ, ρ
wfor the density of chip surface material, υ is described quality transmission rate.
4. the method for claim 1, is characterized in that, the pass of lapping liquid pH value and temperature and grinding clearance MRR is:
wherein, T is temperature, n is pH value, and R is universal gas constant, E
afor energy of activation.
5. an equipment for cmp clearance calculating, is characterized in that, comprises and selects module, analysis module and computing module,
Described selection module, for selected grinding clearance computing formula MRR=kPV, wherein, V is the relative sliding speed between chip and grinding pad, and P is the external pressure putting on chip surface, and k is Preston coefficient;
Described analysis module, for the factor of analyzing influence grinding clearance, obtain the functional equation affecting factor described in grinding clearance, described factor comprises following factor: the effective abrasive grains subnumber in lapping liquid, single-particle removal volume, process of lapping parameter, chip surface grind quality transmission rate, lapping liquid pH value and the temperature of removing thing;
Described process of lapping parameter comprises the sliding speed of the local pressure grinding pad relative to chip between grinding pad with chip;
Described computing module, for being substituted in MRR=kPV by the functional equation of described factor, obtains the specific formula for calculation grinding clearance, calculates grinding clearance MRR according to described specific formula for calculation;
The specific formula for calculation of described grinding clearance MRR is:
Wherein, wherein K
1, K
2for proportionality constant, Δ S is that polishing particles embeds chip portion cross-sectional area, and V is the sliding speed of the relative grinding pad of chip, and K is chemical reaction equilibrium constant, k
efor chemical reaction rate, C
i, C
iIfor lapping liquid interface and chip surface interfacial oxide film concentration, β
i, β
iIfor mass transfer coefficient, P is the local pressure between grinding pad and chip, Δ H
1for polishing particles embeds the degree of depth of chip, R
afor polishing particles radius, A is chip area, η grinding pad rough peak density,
for coarse summit radius, z is grinding pad surface elevation,
d is the distance between chip surface and grinding pad average peak height, and β is weight coefficient, 0≤β≤1, c
vfor polishing particles volumetric concentration, ρ
wfor reaction product density, ρ
afor the density of polishing particles, σ is the standard deviation of peak height, d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, D is the mean diameter of abrasive particle, and R is universal gas constant, E
afor energy of activation, n is pH value.
6. equipment as claimed in claim 5, it is characterized in that, the functional equation calculating described effective abrasive grains subnumber is:
Effective abrasive grains subnumber N=β N
e1+ (1-β) N
e2,
Wherein, 0≤β≤1;
a is chip area, η grinding pad rough peak density,
for coarse summit radius, d is the distance between chip surface and grinding pad average peak height, and z is grinding pad surface elevation,
σ is the standard deviation of peak height; c
vfor polishing particles volumetric concentration, V
ait is abrasive grain volume;
d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, ρ
afor the density of polishing particles, D is the mean diameter of abrasive particle.
7. equipment as claimed in claim 5, is characterized in that, the density of described quality transmission rate and chip surface material with the pass of grinding clearance MRR is:
MRR ∝ ρ
wυ, ρ
wfor the density of chip surface material, υ is described quality transmission rate.
8. equipment as claimed in claim 5, it is characterized in that, the pass of lapping liquid pH value and temperature and grinding clearance MRR is:
wherein, T is temperature, n is pH value, and R is universal gas constant, E
afor energy of activation.
9. a surface topography acquisition methods in cmp simulation process, comprising:
According to grinding clearance influence factor in the influential factor of Process configuration, the Process configuration of adjustment cmp, wherein, one or more in the quality transmission rate that the influence factor of described grinding clearance comprises effective abrasive grains subnumber in lapping liquid, single-particle removes volume, thing is removed in process of lapping parameter, chip surface grinding, lapping liquid pH value and temperature;
The specific formula for calculation of described grinding clearance MRR is:
Wherein, wherein K
1, K
2for proportionality constant, Δ S is that polishing particles embeds chip portion cross-sectional area, and V is the sliding speed of the relative grinding pad of chip, and K is chemical reaction equilibrium constant, k
efor chemical reaction rate, C
i, C
iIfor lapping liquid interface and chip surface interfacial oxide film concentration, β
i, β
iIfor mass transfer coefficient, P is the local pressure between grinding pad and chip, Δ H
1for polishing particles embeds the degree of depth of chip, R
afor polishing particles radius, A is chip area, η grinding pad rough peak density,
for coarse summit radius, z is grinding pad surface elevation,
d is the distance between chip surface and grinding pad average peak height, and β is weight coefficient, 0≤β≤1, c
vfor polishing particles volumetric concentration, ρ
wfor reaction product density, ρ
afor the density of polishing particles, σ is the standard deviation of peak height, d
sfor the extension rate of lapping liquid, ρ
sfor the density before grinding fluid dilution, m
s-afor the mass concentration before grinding fluid dilution, D is the mean diameter of abrasive particle, and R is universal gas constant, E
afor energy of activation, n is pH value;
According to the Process configuration of the described cmp of adjustment, in conjunction with actual process measurement result, matching is carried out to determine final technological parameter to grinding clearance test figure;
Described final technological parameter is used for cmp analog simulation, to obtain chip surface morphology change.
10. method as claimed in claim 9, is characterized in that, described according in the influence factor of grinding clearance to the influential factor of Process configuration, the Process configuration of adjustment cmp, comprising:
S1, according to grinding clearance with grinding clearance influence factor funtcional relationship, the Process configuration of adjustment cmp, described Process configuration comprise in working temperature, pH value, lapping liquid, grinding pad, the titration speed of lapping liquid, working pressure and chip and grinding pad rotating speed one or more;
The Process configuration of the described described cmp according to adjustment, in conjunction with actual process measurement result, matching is carried out to determine final technological parameter to grinding clearance test figure, comprising:
S2, according to the preparation of described technique, in conjunction with actual process measurement result, adopt nonlinear least square method to carry out numerical fitting to grinding clearance test figure, determine final technological parameter;
Wherein, described method can multiple exercise step S1 and S2, with successive optimization Process configuration to determine described final technological parameter.
Described final technological parameter is used for cmp analog simulation, to obtain chip surface morphology change, comprises:
S3, by reading chip surface elemental height, rate equation is removed in conjunction with grinding, the described final technological parameter that step S2 obtains is used for CMP analog simulation, with the change of the pattern of detecting real-time chip surface, described modification of surface morphology comprises the graphic feature that reflection metal and restraining barrier, difference in height between dielectric layer and chip grind flatness.
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| CN102832114B (en) * | 2012-09-11 | 2015-05-13 | 中国科学院微电子研究所 | Method and system for determining chemical mechanical polishing removal rate of aluminum metal gate |
| CN103123922B (en) * | 2012-12-21 | 2015-08-26 | 中国科学院微电子研究所 | Method and system for determining surface morphology of aluminum metal gate chip |
| CN103020383B (en) * | 2012-12-27 | 2015-06-10 | 中国科学院微电子研究所 | Simulation and optimization method of aluminum gate CMP (chemical mechanical polishing) cooperative computing model |
| CN103226627B (en) * | 2013-03-21 | 2016-09-14 | 中国科学院微电子研究所 | Method and device for simulating chip surface morphology |
| CN103605844B (en) * | 2013-11-13 | 2016-05-11 | 中国科学院微电子研究所 | CMP pressure distribution calculation method and grinding removal rate acquisition method |
| CN103753357B (en) * | 2014-01-23 | 2015-12-02 | 南京理工大学 | The axial cutting force Forecasting Methodology of fragile material supersonic vibration assistant grinding |
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| CN104985522B (en) * | 2015-07-03 | 2017-03-08 | 中国科学院微电子研究所 | Method and system for simulating surface appearance |
| JP6406238B2 (en) * | 2015-12-18 | 2018-10-17 | 株式会社Sumco | Wafer polishing method and polishing apparatus |
| CN108733865B (en) * | 2017-04-19 | 2021-10-22 | 中国科学院微电子研究所 | CMP simulation method and device, and method and device for acquiring grinding removal rate |
| CN109299485B (en) * | 2017-07-24 | 2023-02-28 | 中国科学院微电子研究所 | Method and system for establishing CMP (chemical mechanical polishing) simulation model |
| CN108491662B (en) * | 2018-03-30 | 2022-05-03 | 中国科学院微电子研究所 | CMP (chemical mechanical polishing) process simulation method and system |
| JP2019181613A (en) * | 2018-04-06 | 2019-10-24 | 株式会社ノリタケカンパニーリミテド | Vitrified grindstone of coarse-composition homogeneous structure |
| CN109686410B (en) * | 2019-01-29 | 2020-08-28 | 中国科学院微电子研究所 | W CMP multi-physical process simulation method and system |
| CN111046565B (en) * | 2019-12-16 | 2024-03-22 | 中国科学院微电子研究所 | Two-component abrasive particle CMP modeling simulation method |
| CN112257337B (en) * | 2020-10-14 | 2022-09-16 | 上海工程技术大学 | Prediction method for removal rate of wafer CMP (chemical mechanical polishing) material of GMDH (Gaussian mixture distribution) neural network |
| CN113070808B (en) * | 2021-04-27 | 2022-10-28 | 华虹半导体(无锡)有限公司 | Grinding control method of chemical mechanical grinding process |
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