CN103123922A - Method and system for determining surface appearances of aluminum metal gate chips - Google Patents

Abstract

The invention provides a method and a system for determining surface appearances of aluminum metal gate chips. The method comprises determining an average polishing removal rate of aluminum metal gates according to polishing parameters of chemical machinery, chemical reactions between components in a polishing liquid and the surface of an aluminum metal gate chip and a reaction rate equation of the mechanical removal reaction of polishing particles to the chip surface; determining pressure distribution of the aluminum metal gate chip surface according to polishing pad deformation distribution of the aluminum metal gate chip during chemical mechanical polishing, and then determining concentration distribution of the components in the polishing liquid, reaction rate distribution of the mechanical removal reaction of the surface of the aluminum metal gate chip, and determining polishing removal rate distribution of the aluminum metal gates finally; and determining height distribution of the surface of the aluminum metal gate chip according to the polishing removal rate distribution. According to the method and the system for determining surface appearances of the aluminum metal gate chips, effective polishing particle mechanical removal, chemical kinetic removal of the polishing liquid towards the chips and pressure distribution of the aluminum metal gate chip surface in the polishing process are considered comprehensively, and accordingly, aluminum metal gate surface appearances can be determined accurately.

Description

Determine the method and system of aluminum metal grid chip surface pattern

Technical field

The present invention relates to semiconductor manufacturability design field, particularly relate to the method and system of determining aluminum metal grid chip surface pattern in CMP (Chemical Mechanical Polishing) process.

Background technology

The Moore's Law that the integrated level that high-k gate dielectric and metal gate technique (HKMG, High-k Metal Gate) make the development of semicon industry still follow every 18 months chips as the main flow technology of 32 or 28 nanometer nodes doubles.Along with the continuous decline of chip node size, in the chip manufacturing process process, the evenness of chip surface is the key factor of the follow-up manufacturing process of impact and chip yields.Cmp (CMP, Chemical Mechanical Polishing) technique is as realizing the reliable method of chip surface planarization in the manufacturability design, now be widely used in the hyperfine surfacing processing of chip, being the most effective and the most practical technology that realizes at present nanometer grade super smooth not damaged Surface Machining, is also the unique extensive use technology that realizes at present overall planarization.

In " first grid " and " rear grid " two kinds of techniques of HKMG technology, " rear grid " technique needn't stand high-temperature step, can more freely arrange and allocate the work function value of gate material, makes the stability of chip and reliability higher.Therefore, the integrated circuit industry is more prone to select " rear grid " technique when making high performance chips.But " rear grid " technique faces more technique difficulty and design restriction, and the flatness on gate metal surface is extremely difficult up to standard, and it is clean that the incomplete grinding in CMP technique will cause metal not removed, thereby cause short circuit; The overmastication meeting causes gate electrode thinner, produces too high gate resistance and potential contacted etching.In addition, serious excessive polishing can cause adjacent source/drain region to expose, and makes in follow-up mute grid etching process and is attacked.Therefore, need to be actual according to HKMG technique, set up definite method scientific and reasonable, CMP process results accurately and reliably, the height change of real-time estimate metal surface reduces butterfly and erosion after grinding, makes surface reach technological requirement.

At present, the CMP process results of the semicon industry main flow manufacturer of comparative maturity determines that the core technology of method is mainly the CMP technical process for copper, and aluminium during as grid material deposition thickness thinner, very harsh to the CMP technological requirement, definite method of existing CMP process results for copper is difficult to be directly used in the flatening process of alum gate.Domestic main chip manufacturer controls main dependence experience real example method for the CMP technical process of alum gate, general result is by experiment predicted the grinding result of chip under identical grinding condition, this Forecasting Methodology has been ignored lapping liquid, abrasive parameters etc. to the evenness of grinding rear chip and the impact of wafer clearance, and it predicts the outcome and can not accurately embody the grinding effect of CMP technique.Especially in nanoscale node chip manufacture process, the evenness on surface requires high, and the chemical effect of polishing particles is more outstanding in the effect of grinding in removing, the interaction of grinding pad, lapping liquid and chip surface is an extremely complicated process, can not adopt simply the method for experience real example to describe the pattern that CMP grinds rear aluminum metal grid surface.

Summary of the invention

A kind of method of aluminum metal grid chip surface pattern when the purpose of this invention is to provide accurately definite cmp.

To achieve these goals, the invention provides a kind of method of definite aluminum metal grid chip surface pattern, comprise step:

Provide aluminum metal grid chip to carry out the abrasive parameters of cmp;

Determine that chemical reaction and polishing particles that in lapping liquid, each composition and aluminum metal grid chip surface occur remove the reaction rate equation of reaction to aluminum metal grid chip surface machinery, determined the average grinding clearance of aluminum metal grid by described reaction rate equation;

During according to aluminum metal grid chip cmp, grinding pad deformation distributes, and determines aluminum metal grid chip surface pressure distribution;

According to external load and described surface pressure distribution, determine that the machinery of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface is removed the reaction rate distribution of reacting;

The reaction rate of removing reaction according to CONCENTRATION DISTRIBUTION and the described machinery of each composition in described lapping liquid distributes, and determines that the grinding clearance of aluminum metal grid distributes;

Distribute according to described grinding clearance, determine that aluminum metal grid chip surface height distributes.

Preferably, the described abrasive parameters that provides aluminum metal grid chip to carry out cmp comprises:

External load is provided;

The concentration of composition and each composition of lapping liquid is provided.

Preferably, the chemical reaction that in described definite lapping liquid, each composition and aluminum metal grid chip surface occur and polishing particles are removed the reaction rate equation of reaction to aluminum metal grid chip surface machinery, determined the average grinding clearance of aluminum metal grid by described reaction rate equation, comprising:

Determine the chemical reaction that in described lapping liquid, each composition and aluminum metal grid chip surface occur;

Determine that in described lapping liquid, polishing particles is removed reaction to the machinery of aluminum metal grid chip surface;

Determine the reaction rate equation of described chemical reaction and surface machinery removal reaction, determined the relation of metallic concentration changes with time rate and metallic concentration by described reaction rate equation;

According to the relation of described metallic concentration changes with time rate and metallic concentration, determine the average grinding clearance of aluminum metal grid.

Preferably, described during according to aluminum metal grid chip cmp grinding pad deformation distribute, determine aluminum metal grid chip surface pressure distribution, comprising:

Relation when determining aluminum metal grid chip cmp between grinding pad deformation distribution and aluminum metal grid inter-chip pitch;

Determine pressure distribution between grinding pad and aluminum metal grid chip and the grinding pad deformation correlation between distributing;

During according to aluminum metal grid chip cmp, grinding pad deformation distributes, and determines aluminum metal grid chip surface pressure distribution.

Preferably, described according to external load and described surface pressure distribution, determine that the machinery of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface is removed the reaction rate distribution of reacting, comprising:

Obtained the CONCENTRATION DISTRIBUTION of each composition in lapping liquid by the liquid diffusion equation;

Determine that according to external load and surface pressure distribution the reaction rate of the machinery removal reaction of aluminum metal grid chip surface distributes.

Preferably, described according to described grinding clearance distribution, determine that aluminum metal grid chip surface height distributes, and comprising:

Distribute according to the relation between the distribution of aluminum metal grid chip surface height and grinding removal rate distribution and the grinding clearance of aluminum metal grid, adopt Numerical method to determine the distribution of aluminum metal grid chip surface height.

Correspondingly, the present invention also provides a kind of system of definite aluminum metal grid chip surface pattern, it is characterized in that, comprising:

The abrasive parameters configuration module, for the abrasive parameters of configuration aluminum metal grid cmp, described abrasive parameters comprises: grinding temperature, external load, chip and the parameters such as grinding pad relative sliding speed, lapping liquid formula;

The reaction determination module, the relation of metallic concentration changes with time rate and metallic concentration in reaction, reaction rate constant and the reactant that occurs when determining that according to the lapping liquid concentration of component of described abrasive parameters configuration module configuration CMP grinds;

The average clearance determination module that grinds, the relation of metallic concentration changes with time rate and metallic concentration in the reactant that the metallic mass balance during according to grinding and described reaction determination module are determined is determined the average clearance that grinds;

Initial separation distribution determination module is for the spatial distribution of determining the distance between aluminum metal grid chip and grinding pad;

The surface pressure distribution determination module, aluminum metal grid chip and the metric space between grinding pad determined according to described initial separation distribution determination module distribute, and determine aluminum metal grid chip surface pressure distribution;

Grind clearance distribution determination module, determine when CMP grinds that for carrying out the grinding clearance of aluminum metal grid chip surface distributes, comprise the reaction rate distribution determination module of each constituent concentration distribution determination module of lapping liquid and machinery removal reaction.Wherein, each constituent concentration distribution determination module of described lapping liquid is used for determining according to the liquid diffusion equation CONCENTRATION DISTRIBUTION of each composition of lapping liquid, and the mechanical reaction rate distribution determination module of removing reaction is used for carrying out determining when CMP grinds that aluminum metal grid chip surface machinery removal reaction rate everywhere distributes.The average grinding clearance that machinery removal reaction rate distributes and described average grinding clearance determination module is determined that the reaction rate distribution determination module that described grinding clearance distribution determination module utilizes the CONCENTRATION DISTRIBUTION of each composition in the definite lapping liquid of each constituent concentration distribution determination module of described lapping liquid, described machinery to remove reaction is determined determines that the grinding clearance of aluminum metal grid distributes;

Relation between apparent height distribution determination module, the grinding clearance that is used for determining according to described grinding clearance distribution determination module distribute and apparent height distributes and the grinding clearance distributes determines that the height of aluminum metal grid chip surface distributes.

Preferably, described reaction determination module comprises:

Chemical reaction is determined submodule, be used for determining the chemical reaction of generation when CMP grinds, comprise: the reaction rate constant of the chemical reaction of the chemical reaction of the reaction of aluminium and surfactant, aluminium and oxidant, aluminium ion and chelating agent and each reaction, wherein the reaction of aluminium and surfactant is reversible reaction;

Machinery is removed the definite submodule of reaction, and the lapping liquid polishing particles that is used for determining to occur when CMP grinds is to the surface machinery removal reaction of aluminum metal grid, and reaction rate constant;

The reaction of described reaction determination module synthetic chemistry determines that submodule and machinery removes the relation that the reaction that occurs when the grinding of submodule configuration is determined in reaction and reaction rate constant are determined metallic concentration changes with time rate and metallic concentration in product.

Compared with prior art, the method for definite aluminum metal grid chip surface pattern of the present invention has following advantages:

Method and system provided by the invention carries out the average grinding clearance that reaction rate equation that chemical reaction that in the abrasive parameters, lapping liquid of cmp, each composition and aluminum metal grid chip surface occur and polishing particles remove reaction to aluminum metal grid chip surface machinery is determined the aluminum metal grid according to aluminum metal grid chip; And grinding pad deformation distributes during according to aluminum metal grid chip cmp, determine aluminum metal grid chip surface pressure distribution, then the reaction rate of determining the machinery removal reaction of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface distributes, and determines that the grinding clearance of aluminum metal grid distributes; Distribute according to described grinding clearance, determine that aluminum metal grid chip surface height distributes.The present invention consider that effective polishing particles machinery is removed, lapping liquid is removed the chemical kinetics of chip and process of lapping in aluminum metal grid chip surface pressure distribution, a kind of method of determining more accurately aluminum metal grid surface topography is provided.

In addition, the present invention can effectively portray chip surface pressure distribution, pattern variation and the graphic features such as butterfly and erosion, realizes fast manufacturability design CMP processing simulation flow process, shortens the technique adjustment cycle, reduces costs.Therefore, the present invention analyzes the actual process adjustment from grinding mechanism and all has the certain guidance meaning.

Description of drawings

Fig. 1 is the flow chart that the present invention determines the method for aluminum metal grid chip surface pattern;

Fig. 2 is the flow chart of the average grinding clearance of definite aluminum metal grid;

The schematic diagram that reacts on aluminum metal grid surfaces when Fig. 3 is cmp;

Fig. 4 is the schematic diagram that the present invention determines the system of aluminum metal grid chip surface pattern.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described.Obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Based on the embodiment in the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.

Secondly, the present invention is described in detail in conjunction with schematic diagram, and when the embodiment of the present invention was described in detail in detail, for ease of explanation, described schematic diagram was example, and it should not limit the scope of protection of the invention at this.

Just as stated in the Background Art, the semicon industry main flow CMP process results of comparative maturity determines that the core technology of method is mainly the CMP technical process for copper at present, and aluminium during as grid material deposition thickness thinner, very harsh to the CMP technological requirement, have now and determine that for the CMP process results of copper method is difficult to be directly used in the flatening process of alum gate CMP.CMP technical process for alum gate is controlled main dependence experience real example method, general result is by experiment predicted the grinding result of chip under identical grinding condition, this Forecasting Methodology has been ignored lapping liquid, abrasive parameters etc. to the evenness of grinding rear chip and the impact of wafer clearance, and it predicts the outcome and can not accurately embody the grinding effect of CMP technique.Especially in nanoscale node chip manufacture process, the evenness on surface requires high, and the chemical effect of polishing particles is more outstanding in the effect of grinding in removing, the interaction of grinding pad, lapping liquid and chip surface is an extremely complicated process, can not adopt simply the method for experience real example to describe the pattern that CMP grinds rear aluminum metal grid surface.

In order accurately to determine the real-time surface topography of the aluminum metal grid of aluminum metal grid in the CMP process of lapping, the present invention consider that effective polishing particles machinery is removed, lapping liquid is removed the chemical kinetics of chip and process of lapping in aluminum metal grid chip surface pressure distribution, a kind of method of determining more accurately aluminum metal grid surface topography is provided.Below in conjunction with accompanying drawing, the specific embodiment of the present invention is elaborated.

Fig. 1 is the particular flow sheet that the present invention determines the method for aluminum metal grid surface topography, and the below describes the detailed process of the surface topography when determining aluminum metal grid CMP grinding in detail.

Step S1 provides aluminum metal grid chip to carry out the abrasive parameters of cmp.

Abrasive parameters comprises: grinding temperature, external load, chip and the parameters such as grinding pad relative sliding speed, lapping liquid formula.

Carry out usually need to applying external load to improve grinding efficiency to chip when CMP grinds at the aluminum metal grid.

The lapping liquid that aluminum metal carries out adopting when CMP grinds generally includes oxidant, chelating agent, surfactant, polishing particles etc.

Step S2, determine that chemical reaction and polishing particles that in lapping liquid, each composition and aluminum metal grid chip surface occur remove the reaction rate equation of reaction to aluminum metal grid chip surface machinery, determined the average grinding clearance of aluminum metal grid by described reaction rate equation.

The chemical reaction of each active ingredient and aluminum metal grid chip surface have lapping liquid when CMP grinds in, and polishing particles is to the machinery removal reaction on aluminum metal grid surface.

In aluminum metal grid CMP process of lapping, the aluminium generation chemical reaction on the oxidant in lapping liquid, chelating agent and metal gate surface generates oxide and the chelate of aluminium, the aluminium on the surfactant in lapping liquid and metal gate surface produces suction-operated, forms the compound active agent of aluminium and hinders the etching of indentation metal surface." reaction " of aluminium and surfactant is physical adsorption process in essence, and this paper claims that for the ease of unified the discussion " suction-operated of the aluminium on surfactant and metal gate surface " is " chemical reaction ".

In aluminum metal grid chemical mechanical planarization process, the oxide-film at aluminum metal grid rat place is by effectively polishing particles mechanical lapping removal, by grinder rotate, the aluminum metal surface is left in grinding pad friction and outdiffusion effect, simultaneously oxidized, chelating, absorption are continued in fresh aluminium surface under the effect of lapping liquid, removed by mechanical lapping again, move in circles until complete the CMP process of aluminum metal grid.It is a physical mechanical process that machinery is removed reacting quintessence, and this paper claims that for the ease of unified the discussion " in lapping liquid, polishing particles is to the mechanical removal effect in surface of aluminum metal grid " is " reaction ".

According to chemical reaction and the polishing particles of each composition in lapping liquid and the surface generation of aluminum metal grid, the surperficial machinery of aluminum metal grid is removed the reaction rate equation of reaction, can determine the ratio of the aluminum particulate total concentration on the aluminum particulate concentration that comprises in lapping liquid and aluminum metal grid surfaces, i.e. the average grinding clearance of aluminum metal grid.Described aluminum particulate comprises the particle that generates after surfactant, oxidant, chelating agent etc. and reactive aluminum when grinding.

Step S3, during according to aluminum metal grid chip cmp, grinding pad deformation distributes, and determines aluminum metal grid chip surface pressure distribution.

When aluminum metal grid chip carries out the CMP grinding, existence due to polishing particles in lapping liquid, make distributing apart from Existential Space between aluminum metal grid chip and grinding pad, cause the pressure of aluminum metal grid chip surface different, have pressure distribution at aluminum metal grid chip surface.

Step S4 according to external load and described surface pressure distribution, determines that the machinery of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface is removed the reaction rate distribution of reacting.

When aluminum metal grid chip carries out the CMP grinding, distributing apart from Existential Space between aluminum metal grid chip and grinding pad, and there is pressure distribution at aluminum metal grid chip surface, the CMP process of lapping is a dynamic process, cause that in lapping liquid, each composition can not move rapidly along with process of lapping, therefore, aluminum metal grid chip carries out also existing when CMP grinds the CONCENTRATION DISTRIBUTION of each composition in lapping liquid.

The pressure everywhere that polishing particles in lapping liquid is removed reaction rate and aluminum metal grid chip surface to the machinery of aluminum metal grid chip surface is closely related, therefore removes reaction at the machinery of aluminum metal grid chip surface and exists reaction rate constant to distribute.

Step S5, the reaction rate of removing reaction according to CONCENTRATION DISTRIBUTION and the described machinery of each composition in described lapping liquid distributes, and determines that the grinding clearance of aluminum metal grid distributes.

Distribute CONCENTRATION DISTRIBUTION and the machinery of each composition in the average grinding clearance that replaces the aluminum metal grid determined in step S2 of the reaction rate that CONCENTRATION DISTRIBUTION and the machinery of each composition in the lapping liquid of determining in step S4 are removed reaction is removed the reaction rate of reaction, can determine that the grinding clearance of aluminum metal grid distributes.

Step S6 distributes according to described grinding clearance, determines that aluminum metal grid chip surface height distributes.

There is definite relation in aluminum metal grid chip between apparent height distributes and the grinding clearance distributes when carrying out the CMP grinding, can determine that by the grinding clearance distribution of the aluminum metal grid of determining in step S5 aluminum metal grid chip surface height distributes.

Introduce in detail below in conjunction with accompanying drawing the embodiment that the present invention determines the method for aluminum metal grid CMP surface topography:

Execution in step S1 provides aluminum metal grid chip to carry out the abrasive parameters of cmp.

In the present embodiment, carry out applying when CMP grinds uniform pressure P at aluminum metal grid chip.In process of lapping, the parameters such as applied pressure P, grinding temperature T, chip and grinding pad relative sliding speed are fixed value.The component of the lapping liquid that aluminum metal grid chip adopts when carrying out the CMP grinding is generally: surfactant In, and concentration is designated as [In]; Oxidant Oxi, concentration is designated as [Oxi]; Chelating agent CA, concentration is designated as [CA]; Effective polishing particles A.In addition, can also comprise other compositions in lapping liquid, such as deionized water, pH value conditioning agent etc.

Execution in step S2 determines each composition and the surperficial chemical reaction that occurs of aluminum metal grid and the polishing particles reaction rate equation that surface machinery removal is reacted to the aluminum metal grid in lapping liquid, is determined the average grinding clearance of aluminum metal grid by described reaction rate equation.

Referring to Fig. 2, this step specifically comprises the following steps:

Step S21 determines the chemical reaction that in described lapping liquid, each composition and aluminum metal grid chip surface occur.

Aluminum metal grid chip carries out CMP when grinding, and referring to Fig. 3, in the CMP process of lapping is carried out on aluminum metal grid chip 10 surfaces, mainly has following chemical reaction:

1) chemical reaction of aluminium and surfactant:

The chemical reaction of aluminium and surfactant is reversible reaction, wherein, and k ₁When being T for temperature, aluminium and surfactant In reaction generates the positive reaction speed constant of Al surfactant compd A lIn11, k ₂When being T for temperature, Al surfactant compd A lIn is decomposed into the negative reaction speed constant of aluminium and surfactant.The Aluminum Compounds AlIn that generates in the metallic aluminium surface reaction hinders indentation metal surface etching, plays and suppresses and corrosion inhibition." reaction " of aluminium and surfactant is physical adsorption process in essence, and this paper claims that for the ease of unified the discussion " suction-operated of the aluminium on surfactant and metal gate surface " is " chemical reaction ".

2) chemical reaction of aluminium and oxidant:

Wherein, k ₃Oxidized dose of reaction rate constant that is oxidized to the oxide 12 of aluminium of metallic aluminium when being T for temperature.In aluminum metal CMP surface grinding process, aluminum metal oxidized dose of Oxi oxidation in surface forms surface film oxide under the effect of oxidant.

3) chemical reaction of aluminium ion and chelating agent:

Wherein, k ₄When being T for temperature, aluminium ion and chelating agent CA reaction generates the reaction rate constant of large molecule aluminium chelate compound 13, and the large molecule aluminium chelate compound of generation is easy to from the surface disengaging of aluminum metal grid.

Under specified criteria, reaction rate constant k ₁, k ₂, k ₃And k ₄Reaction rate when all being unit concentration for the concentration of reactant.Reaction rate constant is the feature physical constant of a reaction, and whether with temperature, solvent, use the reaction condition such as catalyst relevant, and irrelevant with the concentration of reactant, the size of reaction rate constant has reflected the speed of chemical reaction rate under the specified criteria.

Step S22 determines that in described lapping liquid, polishing particles is removed reaction to the machinery of aluminum metal grid chip surface.

In the CMP process of lapping is carried out on aluminum metal grid chip 10 surfaces, polishing particles in lapping liquid is removed the machineries such as oxide-film of aluminum metal grid chip surface, simultaneously oxidized, chelating, absorption are continued in fresh aluminium surface under the effect of lapping liquid, removed by mechanical lapping again, the machinery of generation is removed reaction and is:

This reaction is not chemical reaction truly, is referred to as reaction for unified discussion here, and its essential meaning is that aluminium ion is removed by machinery, exposes fresh aluminium simple substance surface, and it is surperficial that the residue that machinery is removed will break away from the aluminum metal grid.Wherein, Al ³⁺Represent the oxide-film at metal gate rat place, A represents the polishing particles in lapping liquid, and δ is reaction residue 14, k ₅For machinery is removed reaction rate constant.k ₅Inform under fixed condition machinery and remove the speed of reaction rate, with temperature, pressure, solvent, whether use the reaction condition such as catalyst relevant.

In step S21 and step S22 product of each reaction by grinder rotates, grinding pad rubs and the aluminum metal surface is left in the outdiffusion effect, move in circles, until complete alum gate CMP process of lapping.

Step S23 determines the reaction rate equation that described chemical reaction and surface machinery removal are reacted, and is determined the relation of metallic concentration changes with time rate and metallic concentration by described reaction rate equation.

The chemical reaction and the surface machinery that consider in the CMP process of determining in step S20 and step S1 are removed reaction, the reaction rate equation in the CMP process of lapping can be determined, relation between metallic concentration changes with time rate and metallic concentration can be determined by reaction rate equation.Especially, can determine the surfactant compounds concentration changes with time rate of aluminium and aluminium atomic concentration that aluminum metal grid surfaces comprises and the relation of Al surfactant compound concentration, and the aluminium atomic concentration that comprises of aluminium ion concentration temporal evolution rate and aluminum metal grid surfaces and the pass of aluminium ion concentration are:

$\left\{\begin{array}{c}\frac{\∂[\mathrm{Al}\·\mathrm{In}]}{\∂t}=k_1\left[\mathrm{Al}\right]\left[\mathrm{In}\right]-k_2[\mathrm{Al}\·\mathrm{In}]\\ \frac{\∂\left[A{l}^{3+}\right]}{\∂t}=k_3\left[\mathrm{Al}\right]\left[\mathrm{Oxi}\right]-k_4\left[A{l}^{3+}\right]\left[\mathrm{CA}\right]-k_5\left[A{l}^{3+}\right]\end{array}\right.---\left(1\right)$

Wherein, [AlIn] is the concentration of the chemical reaction product AlIn of aluminium and surfactant, [Al] and [Al ³⁺] represent respectively aluminium atomic concentration and aluminium ion concentration that aluminum metal grid surfaces comprises.

Step S24 according to the relation of described metallic concentration changes with time rate and metallic concentration, determines the average grinding clearance of aluminum metal grid.

When aluminum metal grid chip carried out the CMP Milling balance, the metallic with chip surface in lapping liquid reached mass balance, has:

$\left\{\begin{array}{c}\frac{\∂[\mathrm{Al}\·\mathrm{In}]}{\∂t}=0\\ \frac{\∂\left[A{l}^{3+}\right]}{\∂t}=0\end{array}\right.---\left(2\right)$

The aluminum particulate total concentration [Al] that aluminum metal grid chip surface comprises _TFor:

[Al] _T=[Al]+[Al ³⁺]+[Al·In] （3）

In the CMP process of lapping, the material average removal rate MRR of aluminium is the ratio that comprises the aluminum particulate total concentration on aluminum particulate concentration and aluminum metal grid surfaces in lapping liquid, can be designated as:

$\mathrm{MRR}=\frac{k_4\left[A{l}^{3+}\right]\left[\mathrm{CA}\right]+k_5\left[A{l}^{3+}\right]}{{\left[\mathrm{Al}\right]}_T}---\left(4\right)$

According to above-mentioned (1), (2), (3) and (4) formula, the aluminum metal grid surface C MP that can obtain to consider chemical effect and mechanical lapping coordinative role on average grinds clearance MRR and is:

$\mathrm{MRR}=\frac{k_2{k}_3\left[\mathrm{Oxi}\right]\left(k_4\right[\mathrm{CA}\left]{+k}_5\right)}{k_2{k}_3\left[\mathrm{Oxi}\right]+(k_2+k_1[\mathrm{In}\left]\right)\left(k_4\right[\mathrm{CA}]+k_5)}---\left(5\right)$

Execution in step S3, during according to aluminum metal grid chip cmp, grinding pad deformation distributes, and determines aluminum metal grid chip surface pressure distribution.

The relation of grinding pad deformation distribution and aluminum metal grid inter-chip pitch when at first, needing to determine aluminum metal grid chip CMP grinding.In the CMP process of lapping, ignore lapping liquid to the impact of grinding pad deformation, grinding pad deformation distribution and aluminum metal grid inter-chip pitch H (x, y) satisfy relation:

H(x,y)=H _initial(x,y)+W _b(x,y)-H （6）

Wherein, H is the rigid body distortion of grinding pad, H _Initial(x, y) is that initial aluminum metal gate chip-grinding pad spacing distributes, and can obtain initial aluminum metal gate chip-grinding pad spacing by Method of Stochastic or experimental measurement method.

Grinding pad and aluminum metal grid chip are assumed to and contact, the pressure distribution P between grinding pad and aluminum metal grid chip _b(x, y) and grinding pad deformation distribution W _bCorrelation between (x, y) is:

$W_b(x,y)=k_c{\∫\∫}_A\frac{P_b(x,y)}{\sqrt{{(x-\mathrm{\ξ})}^2+{(y-\mathrm{\η})}^2}}\text{d\ξd\η---}\left(7\right)$

Wherein, A is chip area, k _cBe the contact factor of grinding pad and aluminum metal grid chip,

In addition, grinding pad and aluminum metal grid chip chamber also should satisfy following relation:

$\left\{\begin{array}{c}H(x,y)=0,P_b(x,y)>0,(x,y)\∈A_{\mathrm{contact}}\\ H(x,y)>0,P_b(x,y)=0,(x,y)\∉A_{\mathrm{contact}}\end{array}\right.---\left(8\right)$

Wherein, A _ContactBe grinding pad and aluminum metal grid chip chamber real contact area.

Adopt fast Fourier transform to find the solution the pressure distribution function P that (6)-(8) formula can obtain aluminum metal grid chip surface _b(x, y).

Execution in step S4 according to described surface pressure distribution and external load, determines that the machinery of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface is removed the reaction rate distribution of reacting.

In lapping liquid, the CONCENTRATION DISTRIBUTION of each composition is obtained by the liquid diffusion equation, here do not elaborate, the CONCENTRATION DISTRIBUTION of oxidant Oxi aluminum metal grid chip surface near is designated as [Oxi] (x, y), the CONCENTRATION DISTRIBUTION of surfactant is designated as [In] (x, y), the CONCENTRATION DISTRIBUTION of chelating agent is designated as [CA] (x, y).

When not considering in lapping liquid pressure distribution, the reaction rate that the machinery of aluminum metal grid chip surface is removed reaction is k ₅[Al ³⁺], think that when carrying out CMP grinds, the constant pressure of metal gate chip surface is constant.But it is relevant with the pressure distribution of aluminum metal grid chip surface that actual machine is removed the reaction rate of reaction, and when considering in lapping liquid pressure distribution, to remove the reaction rate of reacting be k to aluminum metal grid chip surface machinery ₅₀P _b(x, y) [Al ³⁺]/P, wherein, the external load that P applies when being grinding, k ₅₀Be the constant relevant to mechanical lapping.Therefore can think, when aluminum metal grid chip carried out the CMP grinding, machinery was removed the reaction rate constant k of reaction ₅Existential Space distributes, and with the pass of pressure distribution in lapping liquid is:

k ₅=k ₅₀P _b(x,y)/P （9）

Execution in step S5, the reaction rate of removing reaction according to CONCENTRATION DISTRIBUTION and the described machinery of each composition in described lapping liquid distributes, and determines that the grinding clearance of aluminum metal grid distributes.

Distribute CONCENTRATION DISTRIBUTION and the machinery of each composition in the average grinding clearance that replaces the aluminum metal grid determined in step S2 of the reaction rate constant that CONCENTRATION DISTRIBUTION and the machinery of each composition in the lapping liquid of determining in step S4 are removed reaction is removed the reaction rate of reaction, the grinding clearance distribution MRR (x, y) that can determine the aluminum metal grid is:

$\mathrm{MRR}(x,y)=\frac{k_2{k}_3\left[\mathrm{Oxi}\right](x,y)\left(k_4\right[\mathrm{CA}](x,y)+k_{50}{P}_b(x,y)/P)}{k_2{k}_3\left[\mathrm{Oxi}\right](x,y)+(k_2+k_1[\mathrm{In}\left](x,y)\right)\left(k_4\right[\mathrm{CA}](x,y)+k_{50}{P}_b(x,y)/P)}---\left(10\right)$

For the grinding that the figure unlike material is arranged, the calculating of MRR needs to consider respectively to remove to select to compare.

Execution in step S6 distributes according to described grinding clearance, determines that aluminum metal grid chip surface height distributes.

Aluminum metal grid chip surface height distribution S (x, y, t) removes with grinding and has following relationship between rate distribution MRR (x, y):

$\frac{1}{|\▿S(x,y,t)|}\frac{\∂S(x,y,t)}{\∂t}=-\mathrm{MRR}(x,y)---\left(11\right)$

With grinding clearance distribution substitution (11) formula of determining in step S5, adopt Numerical method to find the solution, can obtain aluminum metal grid chip surface height distribution S (x, y, t).

So far, adopt the method for definite aluminum metal grid chip surface pattern of the present invention, consider the synergy that the removal of polishing particles machinery and lapping liquid chemistry are removed, determined that from Chemical Kinetics and contact mechanics angle aluminum metal grid chip carries out grinding the clearance distribution when CMP grinds and apparent height distributes.Determine according to the present invention that apparent height that the method for aluminum metal grid chip surface pattern obtains distributes and to further investigate aluminum metal gate figure live width and density to the impact of butterfly and erosion, set up the variation relation between chemical effect and graphic feature, for photoetching, electrical characteristic parameter and device simulation create conditions.

In addition, the present invention can effectively portray chip surface pressure distribution, pattern variation and the graphic features such as butterfly and erosion, realizes fast manufacturability design CMP processing simulation flow process, shortens the technique adjustment cycle, reduces costs.

Correspondingly, the present invention also provides a kind of system of definite aluminum metal grid chip surface pattern, referring to Fig. 4, comprising:

Abrasive parameters configuration module 100, for the abrasive parameters of configuration aluminum metal grid cmp, described abrasive parameters comprises: grinding temperature, external load, chip and the parameters such as grinding pad relative sliding speed, lapping liquid formula.

Reaction determination module 200, the relation of metallic concentration changes with time rate and metallic concentration in reaction, reaction rate constant and the reactant that occurs when determining that according to the lapping liquid concentration of component of described abrasive parameters configuration module configuration CMP grinds.

The average clearance determination module 300 that grinds, the relation of metallic concentration changes with time rate and metallic concentration in the reactant that the metallic mass balance during according to grinding and described reaction determination module 200 are determined is determined the average clearance that grinds.

Initial separation distribution determination module 400 is for the spatial distribution of determining the distance between aluminum metal grid chip and grinding pad.

Surface pressure distribution determination module 500, aluminum metal grid chip and the metric space between grinding pad determined according to described initial separation distribution determination module 400 distribute, and determine aluminum metal grid chip surface pressure distribution.

Grind clearance distribution determination module 600, determine when CMP grinds that for carrying out the grinding clearance of aluminum metal grid chip surface distributes, comprise the reaction rate distribution determination module 620 of each constituent concentration distribution determination module 610 of lapping liquid and machinery removal reaction.Wherein, each constituent concentration distribution determination module 610 of lapping liquid is used for determining according to the liquid diffusion equation CONCENTRATION DISTRIBUTION of each composition of lapping liquid, and the mechanical reaction rate distribution determination module 620 of removing reaction is used for carrying out determining when CMP grinds that aluminum metal grid chip surface machinery removal reaction rate everywhere distributes.The average grinding clearances that machinery removal reaction rate distributes and described average grinding clearance determination module 300 is determined that the reaction rate distribution determination module 620 that described grinding clearance distribution determination module 600 utilizes the CONCENTRATION DISTRIBUTION of each composition in the definite lapping liquid of each constituent concentration distribution determination module 610 of described lapping liquid, described machinery to remove reaction is determined determine that the grinding clearance of aluminum metal grid distributes.

Apparent height distribution determination module 700 for the relation between the grinding clearance distribution of determining according to described grinding clearance distribution determination module 600 and apparent height distribution and the distribution of grinding clearance, determines that the height of aluminum metal grid chip surface distributes.

Wherein, the composition of abrasive parameters configuration module 100 configuration lapping liquids and the concentration of each composition, the composition of lapping liquid comprises surfactant, chelating agent, oxidant, polishing particles etc. usually.Wherein, in lapping liquid, the interpolation speed of the concentration of each composition and lapping liquid also has relation.

Reaction determination module 200 can comprise that chemical reaction determines that submodule and machinery removes reaction and determine submodule, wherein, chemical reaction determines that submodule is used to determine the chemical reaction of generation when CMP grinds, comprise: the reaction rate constant of the chemical reaction of the chemical reaction of the reaction of aluminium and surfactant, aluminium and oxidant, aluminium ion and chelating agent and each reaction, wherein the reaction of aluminium and surfactant is reversible reaction; Machinery is removed to react and determine that submodule reacts mechanical removal the in aluminum metal grid surface for the lapping liquid polishing particles of determining to occur when CMP is ground, and reaction rate constant.The 200 synthetic chemistries reactions of reaction determination module determine that submodules and machinery removes the relation that the reaction that occurs when the grinding of submodule configuration is determined in reaction and reaction rate constant are determined metallic concentration changes with time rate and metallic concentration in product.Wherein, metallic comprises the particle that generates after surfactant, oxidant, chelating agent etc. and reactive aluminum when grinding, and the concentration of metallic represents with surfactant compounds concentration and the aluminium ion concentration of aluminium.

The above is only preferred embodiment of the present invention, is not the present invention is done any pro forma restriction.Any those of ordinary skill in the art, do not breaking away from technical solution of the present invention scope situation, all can utilize method and the technology contents of above-mentioned announcement to make many possible changes and modification to technical solution of the present invention, 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 to any simple modification made for any of the above embodiments, equivalent variations and modification, all still belongs to the scope of technical solution of the present invention protection according to technical spirit of the present invention.

Claims (8)

1. the method for a definite aluminum metal grid chip surface pattern, is characterized in that, comprises step:

Provide aluminum metal grid chip to carry out the abrasive parameters of cmp;

Determine that chemical reaction and polishing particles that in lapping liquid, each composition and aluminum metal grid chip surface occur remove the reaction rate equation of reaction to aluminum metal grid chip surface machinery, determined the average grinding clearance of aluminum metal grid by described reaction rate equation;

During according to aluminum metal grid chip cmp, grinding pad deformation distributes, and determines aluminum metal grid chip surface pressure distribution;

According to external load and described surface pressure distribution, determine that the machinery of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface is removed the reaction rate distribution of reacting;

The reaction rate of removing reaction according to CONCENTRATION DISTRIBUTION and the described machinery of each composition in described lapping liquid distributes, and determines that the grinding clearance of aluminum metal grid distributes;

Distribute according to described grinding clearance, determine that aluminum metal grid chip surface height distributes.

2. method according to claim 1, is characterized in that, the described abrasive parameters that provides aluminum metal grid chip to carry out cmp comprises:

External load is provided;

The concentration of composition and each composition of lapping liquid is provided.

3. method according to claim 1, it is characterized in that, the chemical reaction that in described definite lapping liquid, each composition and aluminum metal grid chip surface occur and polishing particles are removed the reaction rate equation of reaction to aluminum metal grid chip surface machinery, determined the average grinding clearance of aluminum metal grid by described reaction rate equation, comprising:

Determine the chemical reaction that in described lapping liquid, each composition and aluminum metal grid chip surface occur;

Determine that in described lapping liquid, polishing particles is removed reaction to the machinery of aluminum metal grid chip surface;

Determine the reaction rate equation of described chemical reaction and surface machinery removal reaction, determined the relation of metallic concentration changes with time rate and metallic concentration by described reaction rate equation;

According to the relation of described metallic concentration changes with time rate and metallic concentration, determine the average grinding clearance of aluminum metal grid.

4. method according to claim 1, is characterized in that, described during according to aluminum metal grid chip cmp grinding pad deformation distribute, determine aluminum metal grid chip surface pressure distribution, comprising:

Relation when determining aluminum metal grid chip cmp between grinding pad deformation distribution and aluminum metal grid inter-chip pitch;

Determine pressure distribution between grinding pad and aluminum metal grid chip and the grinding pad deformation correlation between distributing;

During according to aluminum metal grid chip cmp, grinding pad deformation distributes, and determines aluminum metal grid chip surface pressure distribution.

5. method according to claim 1, it is characterized in that, described according to external load and described surface pressure distribution, determine that the machinery of the CONCENTRATION DISTRIBUTION of each composition in described lapping liquid, described aluminum metal grid chip surface is removed the reaction rate distribution of reacting, comprising:

Obtained the CONCENTRATION DISTRIBUTION of each composition in lapping liquid by the liquid diffusion equation;

Determine that according to external load and surface pressure distribution the reaction rate of the machinery removal reaction of aluminum metal grid chip surface distributes.

6. method according to claim 1, is characterized in that, and is described according to described grinding clearance distribution, determines that aluminum metal grid chip surface height distributes, and comprising:

Distribute according to the relation between the distribution of aluminum metal grid chip surface height and grinding removal rate distribution and the grinding clearance of aluminum metal grid, adopt Numerical method to determine the distribution of aluminum metal grid chip surface height.

7. the system of a definite aluminum metal grid chip surface pattern, is characterized in that, comprising:

The abrasive parameters configuration module, for the abrasive parameters of configuration aluminum metal grid cmp, described abrasive parameters comprises: grinding temperature, external load, chip and the parameters such as grinding pad relative sliding speed, lapping liquid formula;

The reaction determination module, the relation of metallic concentration changes with time rate and metallic concentration in reaction, reaction rate constant and the reactant that occurs when determining that according to the lapping liquid concentration of component of described abrasive parameters configuration module configuration CMP grinds;

The average clearance determination module that grinds, the relation of metallic concentration changes with time rate and metallic concentration in the reactant that the metallic mass balance during according to grinding and described reaction determination module are determined is determined the average clearance that grinds;

Initial separation distribution determination module is for the spatial distribution of determining the distance between aluminum metal grid chip and grinding pad;

The surface pressure distribution determination module, aluminum metal grid chip and the metric space between grinding pad determined according to described initial separation distribution determination module distribute, and determine aluminum metal grid chip surface pressure distribution;

Grind clearance distribution determination module, determine when CMP grinds that for carrying out the grinding clearance of aluminum metal grid chip surface distributes, comprise the reaction rate distribution determination module of each constituent concentration distribution determination module of lapping liquid and machinery removal reaction.Wherein, each constituent concentration distribution determination module of described lapping liquid is used for determining according to the liquid diffusion equation CONCENTRATION DISTRIBUTION of each composition of lapping liquid, and the mechanical reaction rate distribution determination module of removing reaction is used for carrying out determining when CMP grinds that aluminum metal grid chip surface machinery removal reaction rate everywhere distributes.The average grinding clearance that machinery removal reaction rate distributes and described average grinding clearance determination module is determined that the reaction rate distribution determination module that described grinding clearance distribution determination module utilizes the CONCENTRATION DISTRIBUTION of each composition in the definite lapping liquid of each constituent concentration distribution determination module of described lapping liquid, described machinery to remove reaction is determined determines that the grinding clearance of aluminum metal grid distributes;

Relation between apparent height distribution determination module, the grinding clearance that is used for determining according to described grinding clearance distribution determination module distribute and apparent height distributes and the grinding clearance distributes determines that the height of aluminum metal grid chip surface distributes.

8. system according to claim 7, is characterized in that, described reaction determination module comprises:

Chemical reaction is determined submodule, be used for determining the chemical reaction of generation when CMP grinds, comprise: the reaction rate constant of the chemical reaction of the chemical reaction of the reaction of aluminium and surfactant, aluminium and oxidant, aluminium ion and chelating agent and each reaction, wherein the reaction of aluminium and surfactant is reversible reaction;

Machinery is removed the definite submodule of reaction, and the lapping liquid polishing particles that is used for determining to occur when CMP grinds is to the surface machinery removal reaction of aluminum metal grid, and reaction rate constant;

The reaction of described reaction determination module synthetic chemistry determines that submodule and machinery removes the relation that the reaction that occurs when the grinding of submodule configuration is determined in reaction and reaction rate constant are determined metallic concentration changes with time rate and metallic concentration in product.

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