The content of the invention
The problem that the present invention is solved is to provide a kind of forming method of self-alignment duplex pattern, the material to be etched for ultimately formingThe sidewall profile of the bed of material is preferable.
To solve the above problems, the invention provides a kind of forming method of self-alignment duplex pattern, including：There is provided to be etchedCorrosion material layer；Formed in the material layer to be etched and sacrifice photoresist layer；In the top of the sacrifice photoresist layer and side wallSurface forms polymeric layer；The first mask layer is formed in the polymer layer surface；First mask layer is enteredRow is etched back to, the polymeric layer until exposing the sacrifice photoresist layer top surface, positioned at the sacrifice photoresist layer twoFirst mask layer of side forms the first mask pattern；Removal is described to sacrifice photoresist layer and polymeric layer.
Optionally, the technique for forming the polymeric layer includes：In the top of the sacrifice photoresist layer and sidewall surfacesPolymeric layer is formed using depositing operation；Technique is performed etching to the polymeric layer, the polymeric layer of segment thickness is removed.
Optionally, repeated several times above-mentioned depositing operation and etching technics so that the corner of the polymeric layer of formation isRight angle.
Optionally, the number of times of the repetition is 1 ~ 5.
Optionally, the depositing operation is plasma deposition process, is specifically included：Using at least including CH3F、CH2F2、HBr、CH4One of which or several reacting gas are at the top of the sacrifice photoresist layer and sidewall surfaces form polymeric layer,Wherein, the scope of radio-frequency power is 100 watts ~ 1000 watts, and the scope of reaction temperature is 30 degrees Celsius ~ 60 degrees Celsius, reaction chamber pressureStrong scope is 100 millitorr ~ 200 millitorrs.
Optionally, the etching technics is plasma etch process, is specifically included：Using at least containing CF4、CHF3、CH2F2、O2, Ar one of which etching gas polymeric layer is performed etching, the scope of radio-frequency power is 50 watts ~ 1000 watts, insteadIt is 30 degrees Celsius ~ 60 degrees Celsius to answer the scope of temperature, and reaction chamber pressure range is 5 millitorr ~ 200 millitorrs.
Optionally, the material of first mask layer is silica, silicon nitride, silicon oxynitride, titanium nitride, tantalum nitrideIt is therein one or more.
Optionally, the technique for forming first mask layer is atom layer deposition process, low-pressure chemical vapor depositionTechnique or sub- aumospheric pressure cvd technique.
Optionally, also include, the second mask layer is formed in the material surface to be etched, in second maskMaterial surface is formed sacrifices photoresist layer.
Optionally, after removing the sacrifice bottom anti-reflection layer and sacrificing photoresist layer, it is with first mask patternMask, performs etching to second mask layer, forms the second mask pattern.
Optionally, first mask pattern is removed, with second mask pattern as mask, to the corrosion material to be etchedLayer is performed etching.
Optionally, the material of second mask layer is silica, silicon nitride, carborundum, silicon oxynitride, amorphousCarbon, polysilicon, hafnium oxide, titanium oxide, zirconium oxide, titanium nitride, tantalum nitride, titanium it is therein one or more.
Optionally, also include, with first mask pattern as mask, the material layer to be etched is performed etching.
Optionally, it is cineration technics to remove the photoresist layer and the technique of polymeric layer of sacrificing.
Optionally, the thickness range of the polymeric layer is 1 nanometer ~ 30 nanometers.
Compared with prior art, the present invention has advantages below：
The embodiment of the present invention forms sacrifice photoresist layer in the material layer to be etched, in the sacrifice photoresist layerTop and sidewall surfaces form polymeric layer using depositing operation and etching technics, in the material layer to be etched, polymeric layerSurface forms the first mask layer, first mask layer is etched back, until exposing the sacrifice photoetchingThe polymeric layer of glue-line top surface, the first mask layer positioned at the sacrifice photoresist layer both sides forms the first mask figureShape.Due to foring polymeric layer at the top of the sacrifice photoresist layer and sidewall surfaces, the hardness of the polymeric layer is remoteMuch larger than the hardness for sacrificing photoresist layer, the shape of polymeric layer is not allowed yielding so that the shape for sacrificing photoresist layer will notBecause the stress that the first mask layer is produced is deformed upon, the polymeric layer formed using depositing operation and etching technics is turnedAngle is right angle so that the sidewall profile of final etched features preferably, and by controlling the thickness of the polymeric layer, can be controlledThe spacing of the final etched features of system.
Specific embodiment
Because the sidewall profile that the etched features that material layer to be etched is formed are etched using above-mentioned technology is poor, inventor's warpResearch is crossed to find, when hard mask layer is formed in the sacrificial material layer and sacrifice photoresist layer surface, the hard mask layer meetingStress is produced to sacrificing photoresist layer.Due to photoresist layer hardness less, even across sacrificing light after postexposure bakePhotoresist layer is also more soft, and the stress that the hard mask layer is produced can cause that sacrificing photoresist layer deforms, and it is class ladder to form sectionThe sacrifice photoresist layer of shape so that the side wall for sacrificing photoresist layer is not orthogonal to material surface to be etched so that be subsequently formedMaterial surface to be etched is not orthogonal in the side wall of the sacrifice photoresist layer sidewall surfaces, influence finally treats etachable materialLayer performs etching the sidewall profile of the etched features to be formed.
Therefore, the present invention proposes a kind of forming method of self-alignment duplex pattern, the shape in the material layer to be etchedInto photoresist layer is sacrificed, form poly- using depositing operation and etching technics at the top of the sacrifice photoresist layer and sidewall surfacesCompound layer, forms the first mask layer, to first mask layer in the material layer to be etched, polymer layer surfaceIt is etched back, the polymeric layer until exposing the sacrifice photoresist layer top surface, positioned at the sacrifice photoresist layerFirst mask layer of both sides forms the first mask pattern.Due in the top of the sacrifice photoresist layer and sidewall surfaces shapeInto polymeric layer, the hardness of the polymeric layer is far longer than the hardness for sacrificing photoresist layer, and the shape of polymeric layer is not allowedIt is yielding so that the stress that sacrificing the shape of photoresist layer will not produce because of the first mask layer is deformed upon, and is utilizedThe corner of the polymeric layer that depositing operation and etching technics are formed is right angle, does not interfere with the side wall shape of final etched featuresLooks.
It is understandable to enable the above objects, features and advantages of the present invention to become apparent, below in conjunction with the accompanying drawings to the present inventionSpecific embodiment be described in detail.
Elaborate detail in order to fully understand the present invention in the following description.But the present invention can with it is various notIt is same as other manner described here to implement, those skilled in the art can do class in the case of without prejudice to intension of the present inventionLike popularization.Therefore the present invention is not limited by following public specific implementation.
Fig. 7 to Figure 16 is refer to, is the structural representation of the forming process of the self-alignment duplex pattern of the embodiment of the present invention.
Refer to Fig. 7, there is provided Semiconductor substrate 100, material layer to be etched is formed on the surface of the Semiconductor substrate 100110。
The Semiconductor substrate 100 is silicon substrate, germanium substrate, silicon-Germanium substrate, silicon-on-insulator substrate（SOI）, insulatorUpper germanium（GOI）The one kind therein such as substrate, glass substrate.The material layer to be etched 110 is silicon oxide layer, silicon nitride layer, manyCrystal silicon layer, low-K dielectric material, amorphous carbon, metal level etc. it is therein one or more.In the present embodiment, it is described to be etchedMaterial layer 110 is metal level, and the material of the metal level is aluminium, using self-alignment duplex pattern for mask enters to the metal levelRow etching forms metal interconnecting wires.In other embodiments, the material layer to be etched can also be Semiconductor substrate, using certainlyAlignment double-pattern is performed etching as mask to the Semiconductor substrate.
Fig. 8 is refer to, the second mask layer 120 is formed on the surface of material layer to be etched 110.
Second mask layer 120 be single layer structure or multilayer lamination structure, second mask layer 120Material is silica, silicon nitride, carborundum, silicon oxynitride, amorphous carbon, polysilicon, hafnium oxide, titanium oxide, zirconium oxide, nitridationOne or more in titanium, tantalum nitride, titanium.In other embodiments, second mask layer can also be bottom anti-reflectivePenetrate layer.The technique for forming the second mask layer 120 is chemical vapor deposition method or physical gas-phase deposition.It is describedThe material of the second mask layer 120 is different from the material of material layer to be etched 110, and both have etching selection ratio high, makeThe second mask pattern for being formed of the second mask layer 120 described in later use treats etachable material layer 110 when performing etchingThe loss of the second mask pattern is smaller, is conducive to controlling the pattern of etched features and the size for ultimately forming.And returned due to follow-upThe upper end for etching the first mask pattern for being formed is frequently not the rectangle of rule, with certain radian, directly using describedFirst mask pattern treats the sidewall profile that etachable material layer performs etching the etched features that can influence to ultimately form for mask, becauseThis, in the present embodiment, the second mask layer 120 is formed on the surface of material layer to be etched 110, and later use second is coveredAfter membrane layers 120 form the second mask pattern, removal is shaped as rule positioned at first mask pattern on its surface with the upper endThen rectangular second mask pattern is mask, etches the material layer to be etched, is conducive to the etching figure for controlling to ultimately formThe pattern of shape.And in the present embodiment, second mask layer 120 includes amorphous carbon layer and positioned at the amorphous carbonThe silicon oxide layer of layer surface, when being performed etching to amorphous carbon layer due to dry etch process amorphous carbon layer sidewall profile compared withIt is good, and the silicon oxide layer is larger with the etching selection ratio of metal level, the metal level for being conducive to etch thicknesses larger.
Fig. 9 is refer to, bottom anti-reflection layer 130 is formed and positioned at bottom anti-reflective on the surface of material layer to be etched 120Penetrate the sacrifice photoresist layer 145 on the surface of layer 130.
In the present embodiment, forming the bottom anti-reflection layer 130 and the technique of sacrifice photoresist layer 145 is：Using rotationTurn coating technique and form bottom anti-reflection layer 130 on the surface of the second mask layer 120, in the bottom anti-reflection layer130 surfaces form photoresist layer（It is not shown）, development is exposed to the photoresist layer and is formed and sacrifice photoresist layer 145.In the present embodiment, formed and sacrifice not direct etching bottom anti-reflection layer 130 after photoresist layer 145, covered when being subsequently formed firstAfter film pattern, with first mask pattern as mask, then to the bottom anti-reflection layer 130, the second mask layer 120,Material layer to be etched 110 is performed etching.
In other embodiments, formed after sacrificing photoresist layer, with the sacrifice photoresist layer as mask, etching bottom resistsReflecting layer is formed sacrifices bottom anti-reflection layer, and the polymer being subsequently formed and the first mask pattern are located at sacrifice bottom anti-reflectivePenetrate layer and sacrifice the side wall of photoresist layer.
In other embodiments, the bottom anti-reflection layer can also be the bottom anti-reflection layer for being dissolved in developer solution, work as instituteWhen stating photoresist layer and being exposed development, while being also exposed development to bottom anti-reflection layer so that formed and sacrifice bottom and resistReflecting layer and sacrifice photoresist layer can be formed with a step, save processing step.
In other embodiments, it is also possible to do not form the bottom anti-reflection layer, in the second mask material layer surfacePhotoresist layer is formed, and development is exposed to the photoresist layer, formed and sacrifice photoresist layer.
In other embodiments, it is also possible to do not form the second mask layer in the material surface to be etched, directlyBottom anti-reflection layer and photoresist layer are formed in the material surface to be etched, and it is follow-up being formed in material layer to be etchedThe first mask pattern be mask, the material layer to be etched is performed etching.
Figure 10 is refer to, polymerization is formed using depositing operation at the top of the sacrifice photoresist layer 145 and sidewall surfacesNitride layer 155.
In the present embodiment, the technique for forming the polymeric layer 155 is plasma deposition process, due to the sacrificeThe main element of photoresist layer includes C, therefore can form poly- on sacrifice photoresist layer 145 surface using plasmaCompound layer 155, the polymeric layer 155 has highly cross-linked network structure, and heat endurance, chemical stability and mechanics are strongDegree, hardness are excellent.Because sacrifice photoresist layer 145 surface has high mechanical strength, hardness polymer high so that follow-upThe stress that the first mask layer for being formed is produced will not allow sacrifice photoresist layer to deform upon, the first mask figure being subsequently formedShape is vertical with semiconductor substrate surface, does not interfere with the sidewall profile of the etched features for ultimately forming.It is described plasma-depositedTechnique is specifically included：Reacting gas at least includes CH3F、CH2F2、HBr、CH4One of which is several, will by radio frequency power sourceAfter the reacting gas is plasmarized, the plasma of the reacting gas occurs with the photoresist for sacrificing photoresist layer surfaceReaction, forms polymeric layer at the top of the sacrifice photoresist layer with sidewall surfaces, and the scope of radio-frequency power is 100 watts ~ 1000Watt, the scope of reaction temperature is 30 degrees Celsius ~ 60 degrees Celsius, and reaction chamber pressure range is 100 millitorr ~ 200 millitorrs.
Figure 11 is refer to, the polymeric layer 155 to being formed performs etching technique, remove the polymeric layer of segment thickness.
Due to the possible became uneven of polymeric layer 155 using a plasma deposition process formation, and polymeric layer155 corners are likely to more round and smooth so that the sidewall profile of the first mask pattern being subsequently formed is not good.Therefore, formedAfter one layer of polymeric layer 155, the polymeric layer 155 of segment thickness is performed etching using etching technics so that after etchingThe surface of polymeric layer 155 it is smooth, the corner of the polymeric layer 155 is changed into right angle.In the present embodiment, the etching technicsIt is plasma etch process, specifically includes：CF will at least be contained by radio frequency power source4、CHF3、CH2F2、O2, Ar whereinAfter the etching gas of kind are plasmarized, polymeric layer is performed etching using the plasma of the etching gas, radio frequency work(The scope of rate is 50 watts ~ 1000 watts, and the scope of reaction temperature is 30 degrees Celsius ~ 60 degrees Celsius, and reaction chamber pressure range is 5 millitorrs~ 200 millitorrs.
Conventionally, as the thickness of the first mask layer（That is the width of the first mask pattern）Corresponding to be etchedThe width of the etched features of corrosion material layer, what the width of the etched features of the material layer to be etched was to determine, i.e. the first maskWhat the thickness of material layer was to determine, the spacing between two the first mask patterns between adjacent sacrifice photoresist layer is depended onSacrifice the spacing between photoresist layer.And limited by existing photoetching process, the adjacent spacing sacrificed between photoresist layerIt is larger, therefore, in embodiments of the present invention, can be with deposited polymer layer process described in repeated several times and etch polymers layerTechnique, due to also containing carbon in the polymeric layer that is previously formed, using at least including CH3F、CH2F2、HBr、CH4Wherein oneThe plasma of kind or several reacting gas further can react to form thicker polymer with the polymeric layer being previously formedLayer, so as to control the thickness of polymeric layer for ultimately forming, and then controls adjacent two first sacrificed between photoresist layerSpacing between mask pattern, the spacing between the etched features that control is ultimately formed.In the present embodiment, repeated deposition techniqueIt is 1 ~ 5 with the number of times of etching technics, the thickness range of the polymeric layer 155 for ultimately forming is 1 nanometer ~ 30 nanometers.
Figure 12 is refer to, top surface, sidewall surfaces in the surface of the bottom anti-reflection layer 130 and polymeric layer 155Form the first mask layer 160.
The material of first mask layer 160 be silica, silicon nitride, silicon oxynitride, titanium nitride, tantalum nitride whereinOne or more.The material of first mask layer 160 and the second mask layer 120, bottom anti-reflection layer 130Material is different, with etching selection ratio high so that the first mask figure that the first mask layer 160 described in later use is formedThe loss of the first mask pattern is smaller when shape is performed etching to bottom anti-reflection layer 130, the second mask layer 120, is conducive toThe pattern and size of the etched features that control is ultimately formed.
In other embodiments, when the bottom anti-reflection layer is formed directly into the material surface to be etched, instituteThe material for stating the first mask layer is different from the material of material layer to be etched, and both have etching selection ratio high so that afterContinuous the first mask pattern formed using first mask layer treats the first mask figure when etachable material layer is performed etchingThe loss of shape is smaller, is conducive to controlling the pattern of etched features and the size for ultimately forming.
Because first mask layer 160 is used to being formed the first mask pattern of self-alignment duplex pattern, described theThe width of one mask pattern depends on the thickness of the first mask layer 160 of the sidewall surfaces of polymeric layer 155, therefore, lead toCross the thickness for controlling first mask layer 160, it is possible to the width of the etched features that control is ultimately formed.It is of the invention realThe technique for applying first mask layer of example formation is atom layer deposition process, low-pressure chemical vapor deposition process or sub- normalPressure chemical vapor deposition technique.Because the sedimentation rate of above-mentioned several depositing operations is slower, the first mask layer of formation is equalEven property is preferably, smooth vertical positioned at the side wall of the first mask layer 160 of the sidewall surfaces of the polymeric layer 155, patternPreferably so that the sidewall profile of the first mask pattern being subsequently formed is mask to second with first mask pattern preferablyWhen mask layer or material layer to be etched are performed etching, the pattern for etching the figure for being formed is preferable.
In the present embodiment, using atom layer deposition process in the surface of the bottom anti-reflection layer 130 and polymeric layer 155Top, sidewall surfaces form silicon oxide layer, because the temperature of the atom layer deposition process is relatively low, temperature range is 20 CelsiusDegree will not produce harmful effect to 100 degrees Celsius to described other semiconductor structures.
Figure 13 is refer to, to first mask layer 160（With reference to Figure 12）It is etched back, it is described until exposingThe surface of bottom anti-reflection layer 130 and the polymeric layer 155 positioned at sacrifice photoresist layer 145 surface, positioned at the polymeric layer 155First mask layer 160 of sidewall surfaces forms the first mask pattern 165.
The width of first mask pattern 165 is corresponding with the thickness of the first mask layer 160.When the sacrifice lightPhotoresist layer 145 and polymeric layer 155 overlook when being shaped as strip of visual angle, and first mask pattern 165 is shaped asAround the annular mask pattern for sacrificing photoresist layer 145, polymeric layer 155, in the present embodiment, due to the etching for ultimately formingFigure is metal interconnecting wires, after the sacrifice photoresist layer is subsequently removed, recycles photoresist covering strip zone lineCorresponding first mask pattern, exposes corresponding first mask pattern in strip two ends, is removed by mask of the photoresistCorresponding first mask pattern in the strip two ends so that first mask pattern is changed into the straight line or broken line of bar shaped.
Figure 14 is refer to, using the cineration technics removal sacrifice photoresist layer 145（Refer to Figure 13）And polymeric layer155（Refer to Figure 13）.
It is described because the material of the polymeric layer and photoresist layer is made up of the organic matter that the elements such as C, O, H, N are constitutedThe reacting gas of cineration technics is O2, by the oxygen gas plasma, and utilize the oxygen gas plasma and polymeric layer155 react with the organic matter for sacrificing photoresist layer 145, form volatile carbon monoxide, carbon dioxide, water etc. main rawInto thing, so as to remove the polymeric layer 155 and sacrifice photoresist layer 145.In other embodiments, the cineration technics is anti-Answering gas can also include N2Or H2Deng the N2Or H2Be conducive to improving removal polymeric layer, sacrifice the ability of photoresist layer.
Figure 15 is refer to, with first mask pattern 165 as mask, to the bottom anti-reflection layer 130（Refer to figure14）, the second mask layer 120（Refer to Figure 14）Dry etching is carried out, formation sacrifice bottom anti-reflection layer 135, second are coveredFilm pattern 125.
Because the upper end of the first mask pattern for being etched back to be formed is frequently not the rectangle of rule, with certain arcDegree, directly treats etachable material layer and performs etching the etching figure that can influence to ultimately form using first mask pattern for maskThe sidewall profile of shape, therefore, in the present embodiment, after forming the second mask pattern 125, first mask of the removal positioned at its surfaceFigure 165, sacrifice bottom anti-reflection layer 135, the second mask pattern 125 of regular oblong is shaped as to cover with the upper endFilm, etches the material layer to be etched 110, is conducive to controlling the pattern of etched features for ultimately forming.
In other embodiments, removal is after first mask pattern on its surface, it is also possible to anti-with the sacrifice bottomReflecting layer is mask, etches the material layer to be etched, forms etched features.
Figure 16 is refer to, first mask pattern 165 is removed（With reference to Figure 15）With sacrifice bottom anti-reflection layer 135（GinsengExamine Figure 15）, with second mask pattern 125 as mask, the material layer to be etched 110 is performed etching（With reference to Figure 15）,Form the etched features 115 of self-alignment duplex pattern.
In the present embodiment, the technique for removing first mask pattern 165 and sacrificing bottom anti-reflection layer 135 is wet methodEtching.Because the width of the etched features 115 is determined according to the thickness of the first mask layer, first mask layerThickness can be less than existing process photoetching, the minimum dimension of etching technics so that the width of the etched features 115 is less thanThe width of the figure formed using photoetching process, and the width of polymeric layer ultimately formed by control, can control adjacentEtched features 115 between spacing so that the figure for being smaller than being formed using photoetching process of adjacent etched figure 115Spacing, is conducive to improving the integrated level of integrated circuit.
Although the present invention is disclosed as above with preferred embodiment, it is not for limiting the present invention, any this areaTechnical staff without departing from the spirit and scope of the present invention, may be by the methods and techniques content of the disclosure above to this hairBright technical scheme makes possible variation and modification, therefore, every content without departing from technical solution of the present invention, according to the present inventionAny simple modification, equivalent variation and modification for being made to above example of technical spirit, belong to technical solution of the present inventionProtection domain.