CN101512737A - Composition for forming siliceous film and process for producing siliceous film from the same - Google Patents
Composition for forming siliceous film and process for producing siliceous film from the same Download PDFInfo
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- CN101512737A CN101512737A CNA200780032021XA CN200780032021A CN101512737A CN 101512737 A CN101512737 A CN 101512737A CN A200780032021X A CNA200780032021X A CN A200780032021XA CN 200780032021 A CN200780032021 A CN 200780032021A CN 101512737 A CN101512737 A CN 101512737A
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Abstract
The present invention provides a siliceous film-forming composition having such a small thickness shrinkage ratio that a highly homogeneous siliceous film can be obtained. The invention also provides a trench isolation structure-fabrication process. According to this process, trenches even having very small widths can be homogeneously filled in. The composition contains a solvent and a polysilazane compound obtained by co-ammonolysis of one or a combination of two or more halosilane compounds. The process comprises the steps of coating a surface of a silicon substrate with the above composition, and subjecting the coated substrate to heat-treatment at less than 1000 DEG C under an oxygen atmosphere or an oxidizing atmosphere containing water vapor, so that the composition is converted into silicon dioxide in the form of a film.
Description
Technical field
The present invention relates to be used for forming the composition of siliceous film, also relate to the formation method of the siliceous film of using described composition at electronic installation.At length, the present invention relates to be used to form the composition that contains polysilazane of shallow groove isolation structure, this structure is arranged in the electronic component for the purpose that insulate in the manufacturing of electronic installation such as semiconductor element; The invention still further relates to the method that described composition forms siliceous film of using.
Background technology
In electronic installation such as semiconductor element, semiconductor device such as transistor, resistance etc. are arranged on the substrate.Because described parts must be electrically insulated from each other, need to form the zone of separating them.Described zone is called as " area of isolation ".So far, area of isolation provides by form insulation film selectively on the surface of semiconductor chip usually.
Simultaneously, in the electronic installation technical field, density and integrated level are more and more higher recently.Along with density and integrated level become high more, form the isolation structure that has with the corresponding accuracy of required integrated level and become difficult more.Therefore, expectation provides a kind of new isolation structure to satisfy required accuracy.As one of isolation structure that can satisfy the demands, recess isolating structure has been proposed.Recess isolating structure is then used the filling insulating material groove by form meticulous groove on semiconductor chip, makes with the parts electric insulation of the parts of the side that will be positioned at each groove and opposite side.So the structure to the parts electric insulation can reduce area of isolation with respect to traditional structure, is effective at present to reaching the integrated level that needs therefore.
In order to make recess isolating structure, but application examples such as CVD method or high-density plasma CVD method (for example, seeing patent documentation 1).Yet, if when filling the groove (for example 100nm or littler groove) of the accuracy with present needs according to said method, in the groove of filling some spaces usually appear.Described fault of construction makes the physical strength deterioration of substrate easily and/or slackens insulation property.
For filling slot advantageously, (for example in patent documentation 1) suggestion is by with silicon hydroxide solution coat substrate, and the solution that heating is then applied comes filling slot so that silicon hydroxide is changed into silicon dioxide.Yet in described method, when silicon hydroxide changed into silicon dioxide, volume can shrink, and usually forms crackle.
For avoiding crackle, also advise with the silicon hydroxide in the polysilazane replacement said method (for example in patent documentation 1 and 2).When polysilazane changed into silicon dioxide, its volume contraction was less than silicon hydroxide.Therefore, can avoid the crackle that forms by volume contraction.Described method comprises following steps: the composition that coating contains polysilazane is with filling slot, and the composition of then handling coating under oxidizing atmosphere is to make the recess isolating structure of being made by high-purity and high density silicon dioxide.Because composition fully is filled in the groove, described method has and forms the seldom advantage in space.Yet the inventor has been found that if form recess isolating structure in this way, will have following problems, and promptly owing to the rate of etch on surface and the difference of the rate of etch in the groove, the film of coating composition is by uneven etching.Its reason supposition is as follows.When polysilazane changes into silicon dioxide when forming siliceous film, there are nuance in the oxygen quantity delivered on reaction condition such as surface and the oxygen quantity delivered in the groove.Therefore, it is different that the feature of the siliceous film that obtains in the groove and groove obtain outward, and it depends on the degree of depth of groove.As a result, thus infer the low the problems referred to above that cause of density of the siliceous film in the groove.Especially, become so serious during K cryogenic treatment that the problems referred to above usually need in the restriction about device design and/or processing design, to such an extent as to the film that has in the groove of high depth-width ratio is etched with higher rate of etch.Because semiconductor device is by more and more thickly integrated at present, the position dependence rate of etch becomes more serious problem.
Open communique is not examined in the special permission of [patent documentation 1] No. 3178412 patent of Japan (0005 to 0016 section) [patent documentation 2] Japan 2001-308090 number
Open communique is not examined in the special permission of [patent documentation 3] Japan 2005-120029 number
Summary of the invention
Consider the problems referred to above, an object of the present invention is to provide a kind of composition, also can form fine and close and uniform siliceous film at meticulous groove even be used for.
The present invention relates to a kind of siliceous film formation and use composition, said composition comprises:
A kind of polysilazane compound that comprises the tetravalence silicon atom, four keys of this tetravalence silicon atom all are connected with non-hydrogen atom, and this polysilazane compound obtains by a kind of halogenated silanes compound or common ammonolysis of two or more this halogenated silanes combination of compounds by general formula (A) expression, and general formula (A) is
X-(SiY
2)
n-X (A)
Wherein X is a halogen, and Y is halogen or hydrogen, and condition is that each X and each Y can be same to each other or different to each other, and n is 2 or bigger number; With
A kind of solvent that can dissolve described polysilazane compound.
The invention still further relates to a kind of formation method of siliceous film, this method comprises:
Application step, wherein with above-mentioned siliceous film form with the convex-concave surface of composition silicon-coating substrate and
Cure step, wherein Tu Bu substrate is at oxygen atmosphere or under steam-laden oxidizing atmosphere, heat-treats being lower than under 1000 ℃ the temperature, so that described composition changes into the silicon dioxide of form of film.
The invention still further relates to the siliceous film that method forms that forms by above-mentioned siliceous film, be characterised in that the thickness shrinkage based on the perhydro polysilazane, it has 95% or lower thickness shrinkage.
The invention provides a kind of siliceous film formation and use composition, can obtain having the siliceous film of low thickness shrinkage by it.If recess isolating structure is by described film-forming composition manufacturing, described siliceous film even can be formed uniformly on the dark position in very narrow groove.Therefore, even have in the electronic installation of high depth-width ratio, also can make high-quality recess isolating structure at needs.
Embodiment
Siliceous film forms uses composition
Siliceous film of the present invention forms and comprises a kind of polysilazane compound that contains the tetravalence silicon atom with composition, it obtains by a kind of halogenated silanes compound or common ammonolysis of two or more described halogenated silanes combination of compounds by general formula (A) expression, and general formula (A) is:
X-(SiY
2)
n-X (A)
(wherein X is a halogen, and Y is halogen or hydrogen, and condition is that each X and each Y can be same to each other or different to each other, n be 2 or bigger number); With a kind of solvent that can dissolve described polysilazane.At this, " tetravalence silicon atom " represents a kind of silicon atom, and its four keys all are connected with non-hydrogen atom, that is, any one in four keys of silicon atom is not connected with hydrogen atom.The non-hydrogen atom that is connected with the key of level Four silicon atom can be any atom except hydrogen.The example of non-hydrogen atom comprises oxygen in carbon in nitrogen in the silazane or silicon, the alkyl, the oxygen in the siloxy, halogen, the hydroxyl and the nitrogen in the amino.Four keys of preferred silicon atom and the nitrogen-atoms in the nitrogen-atoms, particularly silazane connect.Described silicon atom can pass through NMR, as DEPT-
29Si-NMR detects.
The halogenated silanes compound preferably contains the silicon atom that is not connected with hydrogen atom, so that the polysilazane compound that obtains by common ammonolysis contains the tetravalence silicon atom.This be because, when if silicon atom only was connected with the silicon atom of other adjacency and/or halogen atom before ammonolysis altogether, its only become with before ammonolysis altogether, still keep or be included in the tetravalence silicon atom that other silicon atoms in the silazane group that is formed by ammonolysis altogether are connected.Yet even silicon atom is being connected with hydrogen atom before the ammonolysis altogether, under the situation of using the halogenated silanes compound represented by above-mentioned general formula (A) (wherein two or more Si atoms continue connection), it becomes the tetravalence silicon atom sometimes.It is unknown that its reason remains.However,, also can obtain containing the polysilazane compound of tetravalence silicon atom, and be applied to siliceous film formation of the present invention with in the composition even the whole Y atoms in the general formula (A) are hydrogen atom.
Composition is coated on substrate etc., then fires with in the known method that forms siliceous film, composition comprises usually as the silane compound of the raw material of siliceous film or silicon nitrogen silane compound.Described compound comprises Si-O key or Si-N key.On the contrary, the polysilazane compound that comprises in the composition of the present invention comprises the tetravalence silicon atom that participates in the Si-N key.In the present invention, the polysilazane compound is oxidized to change into silicon dioxide.The inventor has been found that the film that is so formed by the polysilazane that contains the tetravalence silicon atom has littler thickness shrinkage than the film that is formed by traditional composition that contains silane compound or silicon nitrogen silane compound.Its reason remains to be clearly revealed so far, but can suppose as follows.Because composition of the present invention contains many tetravalence silicon atoms, polysilazane has three-dimensional bulky structure.Therefore.Even the Si-N-Si key is oxidized to change into the Si-O-Si key, bond length shortens subsequently, and the shrinkage degree of volume also can be less.
Molecular weight to the polysilazane compound has no particular limits, but it typically is 1500 or bigger, and preferable range is 2000～3000.
As the above-mentioned raw material of ammonolysis reaction altogether, dichlorosilane also is available.For example, the polysilazane compound that is used for composition of the present invention can be total to ammonolysis by dichlorosilane and the halogenated silanes compound of being represented by general formula (A) and obtain, and general formula (A) is:
X-(SiY
2)
n-X (A)
(wherein X, Y are identical with above-mentioned definition separately with n).At this, halogenated silanes compound that can two or more general formulas of applied in any combination (A).Dichlorosilane can carry out common ammonolysis and prepare the polysilazane compound that can be used for composition of the present invention with the halogenated silanes compound of general formula (A) or the halogenated silanes combination of compounds of the general formula with different n numerical value (A) of two or more.
If necessary, can be with the polysilazane compound applied in any combination of two or more.
Siliceous film of the present invention forms with composition except above-mentioned polysilazane compound, also contains solvent.As solvent, can use any solvent that can dissolve the polysilazane compound.The example of solvent comprises: (a) aromatic, as benzene,toluene,xylene, ethylbenzene, diethylbenzene, trimethylbenzene and triethylbenzene (TEB); (b) aliphatic saturated hydrocarbon is as pentane, isopentane, n-hexane, isohexane, normal heptane, isoheptane, normal octane, isooctane, positive nonane, isononane, n-decane and isodecane; (c) saturated cyclic hydrocarbons is as cyclohexane, decahydronaphthalenes, ethyl cyclohexane, hexahydrotoluene with to terpane; (d) unsaturated cyclic hydrocarbon is as cyclohexene and cinene (citrene); (e) ether is as dipropyl ether, butyl oxide and methyl phenyl ethers anisole; (f) ester is as n-butyl acetate, isobutyl acetate, n-amyl acetate and isoamyl acetate; (g) ketone is as methyl iso-butyl ketone (MIBK).
In order to improve the film forming of composition when being coated with, contraction when controlling Si-N-Si simultaneously and changing into Si-O-Si, siliceous film of the present invention form with composition can contain another kind of polysilazane compound except the polysilazane compound that contains the tetravalence silicon atom as defined above.The density of the film forming of composition and the siliceous film that obtains is tending towards improving by above-mentioned polysilazane compound and the another kind of polysilazane compound that contains the tetravalence silicon atom.Therefore, preferably they are mixed use.Other polysilazane compounds except the polysilazane compound that contains the tetravalence silicon atom can be selected from known compound, are for example represented by general formula (I):
Wherein, R
1～R
3Be hydrogen, the alkyl that contains 1～3 carbon atom or replacement or unsubstituted phenyl independently of one another; And r is the integer of the expression degree of polymerization.
Other polysilazane compounds are not restricted to the compound of above-mentioned general formula (I), can desirably be selected from known compound according to the target purposes.
In the present invention, other polysilazane compounds are not limited especially with the ratio that contains the polysilazane compound of tetravalence silicon atom.Yet based on the weight of whole polysilazane compounds, the content that contains the polysilazane compound of tetravalence silicon atom is generally 5～40wt%, preferred 10～30wt%.
Siliceous film of the present invention forms and is characterised in that with composition the thickness shrinkage of the siliceous film that is formed by described composition reduces by the tetravalence silicon atom in the polysilazane compound with which.Therefore, if when the content of tetravalence silicon atom is quite big, the contraction when Si-N-Si is converted into Si-O-Si is tending towards reducing.Therefore, based on the quantity that is contained in the whole silicon atoms in the composition, the quantity of the tetravalence silicon atom that contains in the composition is preferably 30 atom % or more, further preferred 50 atom % or more.Yet on the other hand, composition preferably contains the trivalent of specified quantitative or silicon atom more at a low price, the contraction when being converted into Si-O-Si with control Si-N-Si, thus suitably keep film shrinkage and property of thin film.The content of trivalent or silicon atom more at a low price is preferably 0.1 atom % or more.In order to increase the content of trivalent or silicon atom more at a low price, the above-mentioned polysilazane compound that contains a plurality of tetravalence silicon atoms can with other polysilazane compound, as other such polysilazane compounds, can contain the tetravalence silicon atom and maybe can use general formula (II) expression.
The solids content that forms with composition for siliceous film has no particular limits.Yet in the scope of 5～30wt%, preferred 20～30wt% is so that the film that obtains can have enough and homogeneous thickness to solids content usually.The solids content of composition is carried out suitable control according to the target thickness of different condition such as coating process and the film that obtains.
The formation method of siliceous film
Formation method according to siliceous film of the present invention can form the homogeneous film that does not contain the space on the convex-concave surface of silicon chip.Therefore, can on the transistor component of electronic installation or capacitor part, form smooth insulation (dielectric before the metal deposition) film.In addition, also can form siliceous film, fill with described siliceous film and formerly be provided at on-chip groove to make recess isolating structure.In explanation subsequently, it is made an explanation at the example that the present invention is used for make recess isolating structure.
Formation method according to siliceous film of the present invention comprises:
Application step, wherein form the convex-concave surface of using composition silicon-coating substrate with siliceous film, this siliceous film forms and contains a kind of polysilazane compound and a kind of solvent that can dissolve this polysilazane compound with composition, this polysilazane compound obtains by a kind of halogenated silanes compound or common ammonolysis of two or more this halogenated silanes combination of compounds by general formula (A) expression, and general formula (A) is
X-(SiY
2)
n-X (A)
(wherein X is a halogen, and Y is halogen or hydrogen, and condition is that each X and each Y can be same to each other or different to each other, n be 2 or bigger number); And
Cure step, wherein Tu Bu substrate is at oxygen atmosphere or under steam-laden oxidizing atmosphere, heat-treats being lower than under 1000 ℃ the temperature, so that described composition changes into the silicon dioxide of form of film.
The halogenated silanes combination of compounds that above-mentioned polysilazane compound is preferably represented by dichlorosilane and general formula (A) is total to ammonolysis and obtains, and general formula (A) is:
X-(SiY
2)
n-X (A)
(wherein X, Y are identical with above-mentioned definition separately with n).At this, can be with the halogenated silanes compound applied in any combination of general formula (A) of two or more.The halogenated silanes compound of dichlorosilane and general formula (A) or the halogenated silanes combination of compounds of the general formula with different n numerical value (A) of two or more can be carried out common ammonolysis and be prepared the polysilazane compound that can use in the method.
If necessary, can be with the polysilazane compound applied in any combination of two or more.
(A) application step
Siliceous film of the present invention forms and is suitable for making recess isolating structure with composition on substrate.Therefore, wait that thereon the substrate of making recess isolating structure has the convex concave that is suitable for forming described structure.Therefore, in the formation method of siliceous film of the present invention, use the silicon chip of convex concave.For making recess isolating structure, use the silicon chip of the groove pattern that is formed with expectation thereon especially.Groove can form by any method.For example, it forms by patent documentation 1 and 2 described methods.The method specific explanations that forms groove is as follows.
At first, on the surface of silicon chip, form silica membrane according to for example thermal oxidation method.The thickness of the silica membrane that forms is generally 5～30nm.
If necessary, on the silica membrane of above-mentioned formation, form silicon nitride film again according to the CVD method that for example reduces pressure.Mask in the silicon nitride film conduct etching step that carries out subsequently, or as the stop layer in the following grinding steps.If the formation silicon nitride film, it has the thickness of 100～400nm usually.
On the silicon nitride film of silica membrane or formation thereon, the coating photoresist.After dry and sclerosis (if necessary), the pattern exposure of photoresist film to expect with coating then develops to form pattern.Exposure can be carried out by any way, for example mask exposure or scan exposure.And consideration resolution etc. can desirably be selected photoresist.
When the photoresist film of formation pattern like this during, the silicon nitride film that provides under the described mask and silica membrane be etched with on silicon nitride film and silica membrane form target pattern as mask.
Thereafter, when the pattern that so forms on silicon nitride film and silica membrane was used as mask, silicon chip was by dry-etching.Thereby, the groove of formation recess isolating structure.
The width of the groove that forms is determined by the pattern that has been transferred on the photoresist film when exposing.The width of the groove that forms on semiconductor device depends on the application target of device, is generally 0.02～10 μ m, preferred 0.05～5 μ m.The degree of depth of groove is 200～1000nm, preferred 300～700nm.According to the present invention, than conventional method, narrower and darker groove can be filled equably.Therefore, method of the present invention is suitable for making narrower and darker recess isolating structure.Form application with the formation method of composition and known siliceous film by traditional siliceous film, forming uniform siliceous film in the bottom of deep trouth is very difficult.Yet, on the contrary, if make recess isolating structure with composition with siliceous film formation of the present invention, groove in the described structure has for example 0.5 μ m or littler width, preferred 0.1 μ m or littler, have 5 or bigger depth-width ratio simultaneously, so even in groove, also can be formed uniformly siliceous film.
On the silicon chip of so preparation, above-mentioned siliceous film formation with composition source as siliceous film be coated with to form composition film thereafter.
Siliceous film forms with composition and can be coated on the substrate by the coating process of expectation.The example of coating process comprises spin coating, curtain-type coating and dip coated.Consider the flatness of the composition film of coating, spin coating is particularly preferred.
The composition film of coating has the thickness of 10～1000nm usually, preferred 50～800nm, thus can use the composition filling slot with the siliceous film formation of coating satisfactorily, make the composition film of coating can have smooth surface simultaneously.
The coating condition depends on the concentration of composition, solvent wherein, coating process etc.By example, the condition of spin coating is described below.
At present, in order to improve product yield, device usually is formed on the huge substrate.Consider this point, preferably with comprising the spin-coating method of multistep, so that the composition film of coating can be formed uniformly on 8 inches or bigger substrate.
At first, the composition of the amount of 0.5～20cc is dropped on the center and several other positions of substrate, so that the film of the composition of drippage can be formed uniformly on whole substrate surface.
Then, substrate is with low relatively rotating speed rotation, and for example the rotating speed with 50～500rpm rotated 0.5～10 second, so that the composition of drippage can spread out (pre-rotation) on whole substrate surface.
Further with high rotating speed rotation, for example the rotating speed with 500～4500rpm rotated 0.5～800 second substrate, so that the composition film of drippage can have the thickness (main rotation) of expectation.
Substrate is more further with high 500rpm of rotating speed or more rotating speed rotation than main rotation, for example the rotating speed with 1000～5000rpm rotated 5～300 seconds, thereby avoid the composition film protuberance at the edge of silicon chip, and make the solvent in the composition film evaporate (rotation eventually) as much as possible.
Consider the size of substrate, the performance of aimed semiconductor device etc., can suitably regulate above-mentioned coating condition.
(B) cure step
If necessary, the composition of coating experience preroast step (specifically describing as follows), the polysilazane film that then heats being coated with changes into siliceous film, thus hardening film.Usually, substrate heats in hardening furnace.
Preferably under steam-laden inactive gas or oxygen atmosphere, in hardening furnace or on hot plate, carry out cure step.Steam is important for silicon-containing compound or silicon-containing polymer and polysilazane compound (if existence) are changed into siliceous (being silicon dioxide) film fully.Water vapour content is preferably 30% or higher, and further preferred 50% or higher, most preferably 70% or higher.Special preferred water vapor content is 80% or higher, because organic compound is changed into siliceous film reposefully, thus the defective in less formation such as space, thus the character of siliceous film improved.The inactive gas that can be used as atmosphere gas comprises nitrogen, argon gas and helium.
Hardening temperature depends on different conditions, forms with the composition of composition and the combination of step as siliceous film.Yet at high temperature, the film of silicon-containing compound, silicon-containing polymer and polysilazane compound will be changed into siliceous film rapidly.On the other hand, at low temperatures, silicon chip is tending towards less oxidation, and its crystal structure is tending towards fine changing, thereby the deterioration of the character of device is limited.Consider this point, cure step is carried out preferred 400～700 ℃ usually under 1000 ℃ or lower temperature.The rate of heat addition that reaches target temperature is generally 1～100 ℃/minute, and the target temperature of sclerosis kept 1 minute～10 hours usually, preferred 15 minutes～3 hours.If necessary, the temperature of sclerosis and atmosphere can progressively change.
The polysilazane compound is so heated and is changed into silicon dioxide to form siliceous film.If siliceous film is formed by traditional known polysilazane compound compositions that only contains, the thickness shrinkage is usually in 15～20% scope.On the contrary, form if siliceous film is formed with composition by the siliceous film that contains the polysilazane compound with tetravalence silicon atom in its structure of the present invention, the thickness shrinkage is 10% or lower.This reason wherein is assumed to be as follows.Owing to have the tetravalence silicon atom, the polysilazane compound has three-dimensional bulky structure, thereby when the Si-N-Si key was converted into the Si-O-Si key, the volume contraction degree was little.As a result, the siliceous film of formation demonstrates little thickness shrinkage.
The thickness shrinkage of siliceous film is according to relative value rather than absolute value evaluation, even because its mensuration is all very sensitive for the minor fluctuations of condition determination traditionally.As the standard of described relative evaluation, can use the thickness shrinkage of the siliceous film that forms by the composition that contains pure perhydrogenate polysilazane substantially.In the case, tentative standard thickness shrinkage is 100%, forms the siliceous film that forms with composition by siliceous film of the present invention and has common 95% or lower relative thickness shrinkage, preferred 92% or lower.
In the present invention, " thickness shrinkage " refer to be used for will coating composition change into the size that the thickness before and after the heat treatment of silica membrane shrinks.At siliceous film under situation about forming on the silicon wafer, in fact thickness shrinkage X can be used for the siliceous film of coating is formed the thickness that changes into the heat treatment front and back of silica membrane with composition by measurement, is then calculated according to following equation by measured value:
X＝[{(thk)
0-(thk)}/(thk)
0]×100
Wherein (thk)
0Being the thickness before the heat treatment, (thk) is the thickness after the heat treatment.Thickness can be by measurements such as ellipsometer tests.
In the foundation manufacture method of recess isolating structure of the present invention, above-mentioned steps is indispensable.Yet if necessary, the step of optional selection subsequently can make up carries out.Following will the step of optional selection being described.
(a) preroast step
Before cure step, can carry out the preroast processing to being coated with the substrate that siliceous film forms with composition.Implementing described step is to be used for removing solvent up hill and dale from the composition film of coating, and the said composition film that hardens in advance.Because the density of the siliceous film that obtains is enhanced, preroast is handled particularly preferably in carrying out in the manufacture method according to the recess isolating structure of having used the polysilazane compound compositions that contains the tetravalence silicon atom of the present invention.
In the preroast step, substrate heats under the temperature of substantial constant usually.Yet the temperature in the preroast step preferably is controlled as gradually and raises, and shrinks between hardening period with the composition film that prevents to be coated with, thereby prevents from the film recessed pockets and/or prevent to form the space in the groove of recess isolating structure.The temperature of preroast step is generally 50～400 ℃, preferred 100～300 ℃.With the common preroast of substrate 10 seconds～30 minutes, preferred 30 seconds～10 minutes.
For elevated temperature gradually in the preroast step, the residing atmosphere of substrate can or continue heating by substep.In order to remove solvent from the composition film of coating, the maximum temperature in the preroast step is usually above being used for the boiling point that siliceous film forms the solvent of using composition.
Implement in the method for the invention under the situation of preroast step, heated substrate was preferably implemented cure step immediately before cooling in the preroast step.Preferably, the temperature of the substrate of cure step to be performed is not less than 50 ℃ and be not higher than the maximum temperature of preroast step.Before being cooled after the preroast step, substrate is implemented cure step immediately, thereby can save energy and the time that is used for once more heated substrate.
(b) grinding steps
After cure step, preferably remove the redundance of the siliceous film of sclerosis.In grinding steps, remove siliceous film on the substrate surface by grinding.Grinding steps can carry out after cure step, if perhaps implemented the preroast step, carries out grinding steps immediately after the preroast step.
Grinding steps is preferably implemented according to cmp (being expressed as " CMP " later on) method.The CMP method can be undertaken by using conventional grinding agent and milling apparatus.The example of grinding agent comprises its water slurry of silica, aluminium oxide, ceria and dispersion, and, if necessary, other grinding agents.Milling apparatus for example is the conventional CMP equipment on the market.
(c) etching step
In above-mentioned grinding steps, on substrate surface, form the siliceous film that forms with composition and almost all be removed by siliceous film.Yet,, preferably carry out etch processes in order to remove residual siliceous film.In etch processes, use etching solution usually.About etching solution, have no particular limits, as long as it can remove residual siliceous film.Etching solution is generally the hydrofluoric acid aqueous solution of fluorinated ammonium.In solution, the content of ammonium fluoride is preferably 5% or higher, and more preferably 30% or higher.
In the recess isolating structure of being made by conventional method, siliceous film usually has so position dependence, to such an extent as to character in groove and the character outside the groove have difference.Therefore, etched or when grinding when substrate with described structure, thus the film on the groove demonstrates the quality deterioration that indenture makes the product that obtains.Yet on the other hand, in the recess isolating structure of being made by method of the present invention, siliceous film has uniform nature like this, to such an extent as to can obtain having the product of expected performance.
Substrate with siliceous film
In the example of making recess isolating structure, the substrate with siliceous film can produce by the formation method of aforesaid siliceous film of the present invention.Substrate with siliceous film produces with composition by the siliceous film formation that coating has little thickness shrinkage.Even in groove, even especially in the bottom of meticulous groove, the siliceous film that obtains has uniform density, makes that the mechanical strength of film also is uniformly, and still keep the uniformity and the flatness of film after etching and attrition process.Therefore, can obtain having high-quality product.
Synthetic embodiment 1
Stir and in the 5kg anhydrous pyridine of 0 ℃ of maintenance, add 404g dichlorosilane (purity: 99% or higher) down.Then, under agitation add the 59g disilicone hexachloride.The mixture that obtains keeps 0 ℃, under agitation is blown into 298L ammonia (purity: 99.9%) in mixture.
Temperature keeps 0 ℃, and mixture keeps stirring 12 hours to react.Subsequently, in mixture, be blown into dry nitrogen 30 minutes removing excess of ammonia, thereby obtain the reactant liquor of pulpous state.Slurry is filtered to remove ammonium chloride, and filtrate is mixed with dimethylbenzene.The mixture that obtains is heated to 50 ℃, and decompression distillation is to remove pyridine under the pressure of 20mmHg.Like this, obtain containing the 20wt% solution that weight average molecular weight is 2000 polymer.With filter (aperture 0.1 μ m) filtering solution, obtain polymer solution.Polymer passes through DEPT-
29Si-NMR estimates, to detect the tetravalence silicon atom.The quantity of tetravalence silicon atom is 70 atom % based on the quantity of the whole silicon atoms that contain in the polymer.And then, confirm that polymer does not contain the Si-Si key, so tetravalence silicon atom key is connected with nitrogen-atoms.
Embodiment 1
The polymer solution that will prepare in synthetic embodiment 1 is spin-coated on the naked silicon chip with the rotary speed of 1000rpm and 20 seconds rotational time, to form the thick coated thin film of 0.6 μ m.The preroast 3 minutes on 150 ℃ hot plate of the substrate of coating then places the hardening furnace under the pure oxygen atmosphere without cooling.Furnace temperature rises to 700 ℃ with 10 ℃/minute speed, and heated substrate 30 minutes is with hardening film in the oxygen atmosphere that contains 80% steam.Thereby formed siliceous film.
The film of the sclerosis that so obtains is measured by FTIR.As a result, at 1080cm
-1Observe the characteristic absorption of Si-O key, thereby confirmed the formation of siliceous film.Yet, on the other hand, do not observe respectively at 3380cm
-1And 2200cm
-1The N-H key and the characteristic absorption of Si-H key, thereby confirm that polysilazane is converted to silicon dioxide (silica).In addition, the stress of film is measured with stressometer, based on the stress evaluation of the substrate before the coating, thereby finds that it is 31MPa.And film carries out etching at the 23 ℃ times aqueous solution with the ammonium fluoride of hydrofluoric acid that contains 0.5wt% and 30wt% as etching solution, and the relative rate of etch of discovery film is 1.56 based on the rate of etch of the silica film of thermal oxidation.
Embodiment 2
The TEG substrate that preparation has the wide groove of 0.05 μ m, 0.1 μ m, 0.2 μ m, 0.5 μ m and 1.0 μ m and covers with silicon nitride liner.On the surface of described substrate, form siliceous film in the mode identical with embodiment 1.After this,, then in the aqueous solution that contains 0.5wt% hydrofluoric acid and 5wt% ammonium fluoride, soaked 30 seconds, fully wash with pure water subsequently and drying vertical perpendicular cuts of TEG substrate along groove.
The cross section of the TEG substrate sem observation of * 50000 times of enlargement ratios.Microscope is placed to the elevation angle that the vertical plane that makes observed direction and cross section is 30 °.Therefore, observe the deep of each groove to estimate etch quantity.The result proves that etch quantity depends on the width of groove hardly, and, even put, also can fully form fine and close siliceous film at the deep-seated of the wide groove of 0.05 μ m.
Synthetic embodiment 2
The step that repeats synthetic embodiment 1 prepares perhydro polysilazane solution, and difference is without disilicone hexachloride.The polysilazane that measures, but do not detect the tetravalence silicon atom.
The comparative example 1
The step that repeats embodiment 1 is to form siliceous film, and difference is the perhydro polysilazane solution with preparation among the synthetic embodiment 2.About the film that forms, use the stress of the mode MEASUREMENTS OF THIN identical and, be respectively 143MPa and 1.62 based on the relative rate of etch of the rate of etch of thermal oxide film with embodiment 1.
The comparative example 2
The process that repeats embodiment 1 is to form siliceous film on the TEG substrate, difference is the perhydro polysilazane solution with preparation among the synthetic embodiment 2.About the film that forms, use the mode identical to measure the etch quantity in the deep in each groove with embodiment 2.As a result, find that etch quantity depends on the width of groove biglyyer than embodiment 2.
Synthetic embodiment 3
In 500g anhydrous dimethyl benzene, add 7g solid sodium (purity 99% or higher).Then, at room temperature, stir and add 30g dichlorosilane (purity 99% or higher) down.After this, reaction temperature remains on 90 ℃, and reaction is carried out 10 hours to synthesize 1,2-two silicon hexachlorides (Wultz coupling).
In another reaction vessel, the anhydrous pyridine of 4kg is remained on 0 ℃.When keeping temperature, stir and add 303g dichlorosilane (purity 99% or higher) down.Then, still keeping temperature is 0 ℃, and that under agitation adds above-mentioned preparation contains 1, the solution of 2-two silicon hexachlorides.Then, the mixture that obtains remains on 0 ℃ again, stirs the ammonia (purity 99% or higher) that is blown into 224L down.Solution remains on 0 ℃ and stirred 12 hours down, thereby reacts.After this, in mixture, be blown into dry nitrogen 30 minutes,, obtain the pulpous state reactant liquor to remove excess of ammonia.With described dope filtration to remove ammonium chloride.
The filtrate that obtains is mixed with dimethylbenzene, is heated to 50 ℃, and pyridine moiety is removed in decompression distillation under the pressure of 20mmHg.Thereby, obtain the polymer solution of 20wt%.Described solution filters with filter (aperture 0.1 μ m).The weight average molecular weight of the polymer that obtains is 3500.Polymer DEPT-
29Si-NMR estimates, to detect the tetravalence silicon atom.
Embodiment 3
The polymer solution of preparation among the synthetic embodiment 3 is spin-coated on the TEG silicon chip that uses among the embodiment 2 under the rotational time of the rotary speed of 1000rpm and 20 seconds.The thickness of the film that forms with the same terms on naked silicon chip is 0.6 μ m.
The preroast 3 minutes on 150 ℃ hot plate of the substrate of coating.
After the preroast, under keeping 200 ℃, substrate places the hardening furnace under the pure oxygen atmosphere.Furnace temperature rises to 400 ℃ with 10 ℃/minute speed, with substrate containing under the oxygen atmosphere of 80% steam heating 30 minutes, with hardening film.Thereby, form siliceous film.
With the TEG substrate so handled vertical perpendicular cuts along groove, then under 23 ℃, in the aqueous solution of the ammonium fluoride of hydrofluoric acid that contains 0.5wt% and 5wt%, soaked 30 seconds, fully wash with pure water subsequently and dry.
The cross section of the TEG substrate sem observation of * 50000 times of enlargement ratios.Microscope is placed to the elevation angle that the vertical plane that makes observed direction and cross section is 30 °.Therefore, the deep of each groove of may observe is to estimate the uniformity of film.The result proves that even the width of groove changes, the etch quantity of trench bottom is also very little, and therefore siliceous film has been filled groove equably.
The comparative example 3
The step that repeats embodiment 3 is to estimate film, and difference is to replace polymer solution with the synthetic polysilazane solution of conventional method.Found that the film that a large amount of polysilazanes that is synthesized by conventional method forms is etched in the bottom of groove, so the uniformity of film is not as the film among the embodiment 3.
Embodiment 4
The step that repeats embodiment 3 has the substrate of siliceous film with generation, and difference is with the alternative substrate of naked silicon chip.
The film of the sclerosis that obtains is measured by FTIR.As a result, at 1080cm
-1Observe the characteristic absorption of Si-O key, thereby confirmed the formation of siliceous film.Yet, on the other hand, do not observe respectively at 3380cm
-1And 2200cm
-1The N-H key and the characteristic absorption of Si-H key, thereby confirm that polysilazane is converted to silicon dioxide (silica).
In addition, the thickness of siliceous film is measured with ellipsometer test.By the thickness after thickness that so obtains and the preroast step, according to following equation calculated thickness shrinkage:
Thickness shrinkage (%)=[thickness after (thickness after the thickness-sclerosis after the preroast)/preroast] * 100
The thickness shrinkage of calculating is 11.5%.
The comparative example 4
The process that repeats embodiment 4 is with the calculated thickness shrinkage, and difference is to use by the synthetic polysilazane solution of conventional method and replaces polymer solution.As a result, find that the thickness shrinkage is 16.7%, be higher than situation with the polysilazane that contains the tetravalence silicon atom.
Synthetic embodiment 4
In 1kg anhydrous dimethyl benzene, add 23g solid sodium (purity 99% or higher).Then, at room temperature, stir and add 101g dichlorosilane (purity 99% or higher) down.After this, reaction temperature remains on 90 ℃, and reaction is carried out 10 hours to synthesize 1,2-two silicon hexachlorides (Wultz coupling).
In another reaction vessel, the anhydrous pyridine of 4kg is remained on 0 ℃.Keep temperature, that under agitation adds above-mentioned preparation contains 1, the solution of 2-two silicon hexachlorides.Then, the mixture that obtains still remains on 0 ℃, stirs the ammonia (purity 99% or higher) that is blown into 81L down.Solution remains on 0 ℃ and stirred 12 hours down, thereby reacts.After this, in mixture, be blown into dry nitrogen 30 minutes, to remove excess of ammonia.The weight average molecular weight of the polymer that so obtains is 3500.Polymer DEPT-
29Si-NMR estimates, to detect the tetravalence silicon atom.
Embodiment 5
The polymer solution of preparation among the synthetic embodiment 4 is mixed with dimethylbenzene, be heated to 50 ℃.The decompression distillation mixture is to remove pyridine moiety under the pressure of 20mmHg.Thereby obtain the xylene solution that contains polymer of 20wt%.In polymer, the quantity of tetravalence silicon atom is 70 atom % based on the quantity of the whole silicon atoms that wherein contain.
Embodiment 6
The polymer solution of preparation among the synthetic embodiment 4 is mixed with various ratios with the polysilazane solution that is synthesized by conventional method.Every kind of mixed solution that so prepares is spin-coated on the naked silicon chip with the rotary speed of 1000rpm and 20 seconds rotational time, to form the thick coated thin film of 0.6 μ m.The preroast 3 minutes on 150 ℃ hot plate of the substrate of each coating places the hardening furnace under the pure oxygen atmosphere subsequently without cooling.Furnace temperature rises to 700 ℃ with 10 ℃/minute speed, and substrate heated 30 minutes under the oxygen atmosphere that contains 80% steam, with hardening film.Thereby, form a plurality of siliceous films with different polysilazane content.
Measure the thickness shrinkage of each siliceous film, find that the thickness shrinkage changes according to the content of polysilazane.When the polymer of embodiment 4 and traditional polysilazane mix with 100% and 20% relative quantity respectively, obtain minimum thickness shrinkage.It is 15.0%.
In addition, the cross section of the TEG substrate sem observation of * 50000 times of enlargement ratios.Microscope is placed to the elevation angle that the vertical plane that makes observed direction and cross section is 30 °.Therefore, observe the deep of each groove to estimate the uniformity of film.Therefore the result proves that etch quantity depends on the width of groove hardly, also can fully form fine and close siliceous film even put at the deep-seated of the wide groove of 0.05 μ m.
Claims (7)
1. a siliceous film forms and uses composition, comprises:
A kind of polysilazane compound that comprises the tetravalence silicon atom, four keys of this tetravalence silicon atom all are connected with non-hydrogen atom, and this polysilazane compound obtains by a kind of halogenated silanes compound or common ammonolysis of two or more this halogenated silanes combination of compounds by general formula (A) expression, and general formula (A) is
X-(SiY
2)
n-X (A)
Wherein X is a halogen, and Y is halogen or hydrogen, and condition is that each X and each Y can be same to each other or different to each other, and n is 2 or bigger number; With
A kind of solvent that can dissolve described polysilazane compound.
2. according to the siliceous film formation composition of claim 1, wherein said polysilazane compound is total to ammonolysis by dichlorosilane and one or more the halogenated silanes combination of compounds by general formula (A) expression except dichlorosilane and obtains.
3. use composition according to the siliceous film formation of claim 1 or 2, wherein based on the quantity that is contained in the whole silicon atoms in the described polysilazane compound, the quantity that is contained in the described tetravalence silicon atom in the described polysilazane compound is 30 atom %.
4. form according to each siliceous film in the claim 1～3 and use composition, it is characterized in that also containing other polysilazane compounds except described polysilazane compound.
5. form according to each siliceous film in the claim 1～3 and use composition, it is characterized in that also containing polysilazane compound by general formula (I) expression:
Wherein, R
1～R
3Be hydrogen, the alkyl that contains 1～3 carbon atom or replacement or unsubstituted phenyl independently of one another; And r is the integer of the expression degree of polymerization.
6. the formation method of a siliceous film comprises:
Application step, wherein with each siliceous film in the claim 1～5 form with the convex-concave surface of composition silicon-coating substrate and
Cure step, wherein Tu Bu substrate is at oxygen atmosphere or under steam-laden oxidizing atmosphere, heat-treats being lower than under 1000 ℃ the temperature, so that described composition changes into the silicon dioxide of form of film.
7. by the siliceous film that method forms that forms of the siliceous film of claim 6, it is characterized in that the thickness shrinkage based on the perhydro polysilazane, the thickness shrinkage of this siliceous film is 95% or lower.
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|---|---|---|---|
| JP2006244611 | 2006-09-08 | ||
| JP244611/2006 | 2006-09-08 | ||
| JP049995/2007 | 2007-02-28 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115038741A (en) * | 2019-12-31 | 2022-09-09 | 乔治洛德方法研究和开发液化空气有限公司 | Curable formulations for forming low-k dielectric silicon-containing films using polycarbosilazanes |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115038741A (en) * | 2019-12-31 | 2022-09-09 | 乔治洛德方法研究和开发液化空气有限公司 | Curable formulations for forming low-k dielectric silicon-containing films using polycarbosilazanes |
| CN115038741B (en) * | 2019-12-31 | 2024-04-02 | 乔治洛德方法研究和开发液化空气有限公司 | Curable formulations for forming low k dielectric silicon-containing films using polycarbosilazanes |
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