CN103187245A - Method of photoetching of block copolymer through directed self-assembly - Google Patents

Abstract

The invention provides a method of photoetching of a block copolymer through directed self-assembly. The method of photoetching of the block copolymer through directed self-assembly comprises the steps of forming a side wall on a side wall surface of an isolation interval area of a photoetching pattern, using the photoetching pattern and the side wall to serve as masking film to irradiate the surface of a phenylethyltrichlorosilane (PETS) layer so as to form a chemical pattern, reducing the width of a chemical modification area in the chemical pattern, coating the block copolymer on the surface of the PETS layer with the chemical pattern in a spin mode, forming a self-assembly layer, carrying out annealing, and combining chemical guidance directed self-assembly (DSA) and morphology guidance DSA to form a periodic structure domain.

Description

A kind of photoetching method by directed self assembly block copolymer

Technical field

The present invention relates to a kind of semiconductor making method, particularly a kind of photoetching method by directed self assembly block copolymer.

Background technology

Along with development of semiconductor, existing photoetching technique and can not adapt to structure manufacturing on nano-scale.Has self assembly (self-assembly, SA) self-assembled film of characteristic is divided into self-assembled monolayer (self-assembly monolayer by its membrane formation mechanism, SAM) and successively self-assembled film (Layerby layer self assembled membrane), at present the research in the big molecule self assembly of high polymer field is primarily aimed at the combination of liquid crystal polymer, block copolymer, the polymer that can form key or hydrogen bond and oppositely charged system, the SAM of block copolymer wherein is because its self assembly characteristic provides another approach for the patterning on the nano-scale.Be example with the diblock copolymer, behind substrate surface spin coating diblock copolymer, can spontaneously be assembled into two kinds of polymer blocks combinations with periodic structure by polymer microphase-separated of (for example, by enforcement thermal annealing when being higher than the glass transition temperature of described polymer or by solvent annealing) after annealing of forming diblock copolymer.But the periodic structure of this polymer blocks combination is not a kind of ordered structure territory, as shown in Figure 1.Therefore in order to form orderly domain (well-organized structures) at nano-grade size directed self assembly (Directedself-assembly has been proposed, DSA) block copolymer technology, thus another approach provided for the patterning that carries out photoetching at nano-scale.DSA can be divided into pattern guiding DSA and chemistry guiding DSA according to its principle.Wherein, the advantage that chemistry guiding DSA compares pattern guiding DSA is, longer ordered structure territory can be provided, and realizes more accurate arrangement.

In conjunction with the photolithography process figure of chemistry guiding DSA block copolymer in Fig. 3～9 explanations prior art as shown in Figure 2, its concrete steps are as follows:

Step 201, Fig. 3 is the cross-sectional view of thelithography step 201 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 3, deposition phenethyl trichlorosilane (phenylethyltrichlorosilane, PETS)layer 302 on the wafer.

In the context of the application's case, term " semiconductor substrate " or " semiconduction substrate " or " semiconduction wafer fragment " or " wafer fragment " or " wafer " are interpreted as meaning the arbitrary structure that comprises semi-conducting material (including but not limited to build semiconduction material), for example, semiconductor wafer (separately or comprise on it component of other material) and semiconduction material layer (separately or comprise the sub-assembly of other material).Term " substrate " refers to arbitrary supporting structure, includes but not limited to above-mentioned semiconduction substrate, wafer fragment and wafer.

Substrate in this step is that example describes with the wafer, and described wafer has silicon substrate 300 (substrate), and deposition ofsilica layer 301 on the wafer device side ofsilicon substrate 300 is at the surface deposition PETS of describedsilicon dioxide layer 301 layer 302.The step ofdeposition PETS layer 302 is prior art, repeats no more.

Step 202, Fig. 4 is the cross-sectional view of thelithography step 202 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 4, applies photoresist on thePETS layer 302, described photoresist patterningforms photoengraving pattern 403 after the photoetching.

In this step, photoetching refers to expose and develops and forms the step ofphotoengraving pattern 403, and this step is prior art, repeats no more.It should be noted that,photoengraving pattern 403 has defined the array of the raceway groove that is arranged in parallel, each raceway groove has following structure: sidewall and bottom surface, wherein, the length of raceway groove is several times as much as the width of its bottom surface, and part PETS layer exposes as the bottom surface of raceway groove, and the part photoresist forms spacer interval between raceway groove, as seen, the sidewall of the spacer interval sidewall of raceway groove just.The width sum of the width of raceway groove bottom surface and spacer interval has defined the chemical guiding DSA cycle (Ls), and Ls is subjected to the accuracy limitations of photoetching technique.

Step 203, Fig. 5 is the cross-sectional view of thelithography step 203 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 5, be that mask shinesPETS layer 302 withphotoengraving pattern 403, form chemical pattern (chemical pattern) onPETS layer 302 surface.

In this step, irradiation is with extreme ultraviolet light known in the art (EUV), X ray or electron beam (E-bearn) exposuresystem PETS layer 302 to be shone under the oxygen atmosphere.For thepart PETS layer 302 that is not covered byphotoengraving pattern 403, under above-mentioned light beam or electron beam irradiation, with oxygen generation chemical reaction, make it by nonpolar chemical modification (Chemically modified)zone 501 of changing polarity into, its width is w; Anotherpart PETS layer 302 that is covered byphotoengraving pattern 403 does not then have and oxygen generation chemical reaction, still keeps nonpolar state, is called on-chemically modified (Non-Chemically modified)zone 502.

Step 204, Fig. 6 is the cross-sectional view of thelithography step 204 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 6, strippingphotolithography pattern 403.

In this step, strippingphotolithography pattern 403 can be with dry etching or wet etching.

Step 205, Fig. 7 is the cross-sectional view of thelithography step 205 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 7, at thePETS layer 302 surperficial spin coating diblock copolymer with chemical pattern as SAM.

Present embodiment 701 is that example describes (PS-b-PMMA) with diblock copolymer poly-(styrene-block-methyl methacrylate).

Molecular weight that can be by adjusting different polymer blocks in the block copolymer in the prior art and the film form (size and the shape that comprise microphase-separated domains) that volume fraction is controlled patterned film are to produce forms such as sheet, cylinder or sphere.For instance, for the ratio of two blocks (polymer A and polymer B) of diblock polymer greater than about 80: 20 volume fraction, but the block copolymer microphase-separated also is self-assembled into periodically spherical structure territory, and wherein the matrix of polymer A surrounds the matrix of polymer B.For the situation of ratio between about 60: 40 and 80: 20 of two blocks, described diblock copolymer is assembled into the cylinder of polymer B in the polymer A matrix of periodicity hexagon closs packing or honey-comb shape array.For the ratio between about 50: 50 and 60: 40, can form the laminar structured territory of described block or replace candy strip.

Step 206, Fig. 8 is the cross-sectional view of thelithography step 206 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 8, diblock copolymer is annealed, its self assembly forms two kinds of polymer blocks combinations, and two kinds of polymer blocks combinations are the ordered structure territories with periodic structure.

In this step, the domain cycle (L of polymer blocks combination₀) L satisfies condition₀During=Ls, because the polarity of chemistry guiding DSA is selected, two kinds of polymer blocks combinations can form the ordered structure territory with periodic structure.Wherein, thechemical modification zone 501 of described polarity will guide the PMMA preferential wetting, form the PMMA block (PMMA block) 801 of strip above it, in the nonpolar on-chemically modifiedzone 502 that presents the neutral wetting state, according to the characteristic of diblock copolymer, PS will form the PS block (PS block) 802 of strip in the on-chemically modifiedzone 502 of its both sides centered by the PMMA matrix.

Step 207, Fig. 9 is the cross-sectional view of thelithography step 207 of chemistry guiding DSA block copolymer in the prior art, as shown in Figure 9, a kind of polymer blocks of selective removal forms patterned film 901.

After DSA, optionally remove forexample PMMA block 801 of a kind of polymer blocks, with the patterned film 901 that forms as etch mask.Because the domain cycle (L of related polymer blocks combination in this method₀) be to be determined by the strand length (MW) of block copolymer, therefore the definition of the patterned film 901 that forms is better than such as with other technology such as photolithographies, and the cost of described DSA block copolymer photoetching technique is well below the cost of the electron beam lithography with suitable definition or EUV photoetching technique simultaneously.

By above-mentioned steps as seen, the chemistry guiding DSA of prior art forms the polymer blocks combination in the ordered structure territory with periodic structure, and the formed patterned film of certain polymer blocks of follow-up removal is subjected to the restriction of lithographic accuracy, so also limited to the characteristic size of patterned film.

Summary of the invention

In view of this, the technical problem that the present invention solves is: in the photoetching method of the directed self assembly block copolymer of chemistry guiding, the patterned film that forms behind the ordered structure territory with periodic structure that polymer blocks forms and certain polymer blocks of follow-up removal is subjected to the lithographic accuracy restriction of photoengraving pattern.

For addressing the above problem, technical scheme of the present invention specifically is achieved in that

A kind of photoetching method by directed self assembly block copolymer provides a substrate, deposition PETS layer on the described substrate, apply photoresist on the described PETS layer, described photoresist patterning forms photoengraving pattern after the photoetching, and described photoengraving pattern comprises spacer interval and first raceway groove, and this method comprises:

Described photoengraving pattern surface deposition cover layer;

The described cover layer of dry etching forms side wall at the spacer interval sidewall of described photoengraving pattern;

Be that mask shines described PETS layer with described photoengraving pattern and side wall, form chemical pattern at described PETS laminar surface, the width in chemical modification zone is less than the width of described first raceway groove in the described chemical pattern;

Peel off described photoengraving pattern and side wall;

Has the PETS laminar surface spin coating block copolymer of chemical pattern as the self assembly layer described;

After the described substrate annealing, the block copolymer self assembly forms the polymer blocks combination, and described polymer blocks combination is the ordered structure territory with periodic structure;

Remove certain polymer blocks and form patterned film.

Described cover layer is silicon dioxide, silicon nitride, nitrogen doping diamond dust, perhaps amorphous carbon.

Described stripping photolithography pattern and side wall can be with dry etching or wet etchings.

Described block copolymer is diblock copolymer, triblock copolymer or segmented copolymer.

Described diblock copolymer be poly-(styrene-block-methyl methacrylate) (PS-b-PMMA), polyethylene glycol oxide-polyisoprene, polyethylene glycol oxide-polybutadiene, polyethylene glycol oxide-polystyrene, polyethylene glycol oxide-polymethyl methacrylate, the pyridine of polystyrene-poly vinyl pyrrole, polystyrene-poly isoprene (PS-b-PI), polystyrene-poly butadiene, polybutadiene-polyvinyl Pyrrolizidine or polyisoprene-polymethyl methacrylate; Described triblock copolymer is poly-(styrene-block methyl methacrylate-block-ethylene oxide).

Described annealing is carried out in carbon disulfide atmosphere.

The temperature range of described annealing is 100 to 300 degrees centigrade, and the time range of described annealing is 8 to 12 hours.

The domain period L of the width sum Ls of the bottom surface of described first raceway groove and described spacer interval and the combination of described polymer blocks₀Relation satisfy nL₀=Ls, n are smaller or equal to 10 integer more than or equal to 2.

The width range in described chemical modification zone is smaller or equal to 60 nanometers.

As seen from the above technical solutions, the invention provides a kind of photoetching method by directed self assembly block copolymer, this method forms side wall in the sidewall surfaces of photoengraving pattern, form chemical pattern with photoengraving pattern and side wall as mask irradiation PETS laminar surface, thereby reduce the width in the chemical modification zone in the described chemical pattern, then in the PETS laminar surface spin coating copolymer with chemical pattern and annealing; In annealing process, at first form specific morphology based on chemistry guiding DSA at substrate surface, spontaneously be not assembled into the polymer blocks combination with periodic structure in the chemical modification zone based on pattern guiding DSA then; Follow-uply obtain patterned film by the polymer blocks combination with periodic structure, this method has overcome the lithographic accuracy restriction of photoengraving pattern, has increased pattern density and the precision of the patterned film of the photoetching formation by directed self assembly block copolymer.

Description of drawings

Fig. 1 is the periodic structure schematic diagram of the polymer blocks combination in non-ordered structure territory in the prior art;

Fig. 2 is the photolithography process figure of chemistry guiding DSA block copolymer in the prior art;

Fig. 3～9 are the cross-sectional view of the photoetching of chemistry guiding DSA block copolymer in the prior art;

Figure 10 is the photolithography process figure of the specific embodiment of the invention one DSA block copolymer;

Figure 11～19 are the cross-sectional view of the photoetching of the specific embodiment of the invention one DSA block copolymer.

Embodiment

For make purpose of the present invention, technical scheme, and advantage clearer, below with reference to the accompanying drawing embodiment that develops simultaneously, the present invention is described in more detail.

The present invention proposes a kind of photoetching method by directed self assembly block copolymer, this method forms side wall in the sidewall surfaces at photoengraving pattern, form chemical pattern with photoengraving pattern and side wall as mask irradiation PETS laminar surface, thereby reduce the width in the chemical modification zone in the described chemical pattern, then in the PETS laminar surface spin coating copolymer with chemical pattern and annealing, thereby at first guide DSA after substrate surface forms specific morphology based on chemistry, spontaneously be not assembled into the polymer blocks combination with periodic structure in the chemical modification zone based on pattern guiding DSA again, removing wherein at last, certain polymer blocks forms patterned film.

Specific embodiment one

In conjunction with the photolithography process figure of Figure 11～19 explanations DSA block copolymer of the present invention as shown in figure 10, its concrete steps are as follows:

Step 1001, Figure 11 is the cross-sectional view of thelithography step 1001 of DSA block copolymer of the present invention, as shown in figure 11, deposition phenethyl trichlorosilane layer (PETS) 302 on the wafer.

In the context of the application's case, term " semiconductor substrate " or " semiconduction substrate " or " semiconduction wafer fragment " or " wafer fragment " or " wafer " are interpreted as meaning the arbitrary structure that comprises semi-conducting material (including but not limited to build semiconduction material), for example, semiconductor wafer (separately or comprise on it component of other material) and semiconduction material layer (separately or comprise the sub-assembly of other material).Term " substrate " refers to arbitrary supporting structure, includes but not limited to above-mentioned semiconduction substrate, wafer fragment and wafer.In the present embodiment, provide a wafer (wafer) as substrate, described wafer has silicon substrate (substrate) 300, hassilicon dioxide layer 301 in the wafer device side ofsilicon substrate 300, at the surface deposition PETS of describedsilicon dioxide layer 301 layer 302.The step ofdeposition PETS layer 302 is prior art, repeats no more.It should be noted that can also deposit other semi-conducting materials onsilicon substrate 300 replacessilicon dioxide layer 301, that is to say that the present invention is including but not limited to the material surfacedeposition PETS layer 302 ofsilicon dioxide layer 301.

Step 1002, Figure 12 as shown in figure 12, applies photoresist atPETS layer 302 for the cross-sectional view of thelithography step 1002 of DSA block copolymer of the present invention, and the photoresist patterning formsphotoengraving pattern 403 after the photoetching.

In this step, photoetching refers to expose and develops and forms the step ofphotoengraving pattern 403, and this step is prior art, repeats no more.It should be noted that,photoengraving pattern 403 has defined the array of first raceway groove that is arranged in parallel, each first raceway groove has following structure: sidewall and bottom surface, the part pet layer exposes as the bottom surface of first raceway groove, and the part photoresist forms spacer interval between first raceway groove, as seen, the sidewall of the spacer interval sidewall of raceway groove just.The width sum of the width of the first raceway groove bottom surface and spacer interval has defined the cycle (Ls) of chemical guiding DSA, Ls is determined by lithographic accuracy, so under the prerequisite that does not change existing photoetching technique, the limiting value of Ls can't change,concrete photoengraving pattern 403 formation methods are identical with prior art with the length of step and Ls, repeat no more.

Step 1003, Figure 13 is the cross-sectional view of thelithography step 1003 of DSA block copolymer of the present invention, as shown in figure 13,photoengraving pattern 403 surfacedeposition cover layers 1301;

In this step, describedcover layer 1301 can be silicon dioxide, silicon nitride, nitrogen doping diamond dust (NDC, Nitrogen Doped silicon Carbide) such as boron nitride (BN) and carbonitride of silicium (SiCN), perhaps amorphous carbon, material difference according tocover layer 1301, its corresponding deposition process is prior art, repeats no more

Step 1004, Figure 14 is the cross-sectional view of thelithography step 1004 of DSA block copolymer of the present invention, as shown in figure 14, the describedcover layer 1301 of dry etchingforms side wall 1401 at the spacer interval sidewall ofphotoengraving pattern 403.

In this step, because dry etching is anisotropy, so thereby can keep the part of covering layer that is attached on the spacer interval sidewall when removal is deposited on the part of coveringlayer 1301 of the spacer interval top ofphotoengraving pattern 403 and trench bottom forms side wall 1401.Because the existence ofside wall 1401 has increased the width (area of isolation ofphotoengraving pattern 403 formation originally andside wall 1401 are simultaneously as area of isolation) of spacer interval, also just correspondingly reduce first channel width, for example by regulating the thickness ofsedimentary cover 1301, the width control of first raceway groove after will dwindling is below 60 nanometers (nm).As everyone knows, the restriction of existing photoetching technique has reached the limit of first channel width, theside wall 1401 that the method utilization that the present invention proposes forms further reduces first channel width, can overcome the restriction of lithographic accuracy ofphotoengraving pattern 403 to the L of follow-up block copolymer₀Restriction.Dry etching in this step can be plasma etching, and the relevant parameter of dry etching and the method for controlling stopping of dry etching are prior art, for example, according to thickness and the dry etching speed ofcover layer 1301, the control dry etching time; Perhaps adopt stopping of end point determination method control dry etching.

Step 1005, Figure 15 is the cross-sectional view of thelithography step 1005 of DSA block copolymer of the present invention, as shown in figure 15, is mask irradiation PETS layer withphotoengraving pattern 403 andside wall 1401, forms chemical pattern at the PETS laminar surface.

In this step, irradiation is with extreme ultraviolet light known in the art (EUV), X ray or electron beam (E-bearn) exposure system the PETS layer to be shone under the oxygen atmosphere.For the part PETS layer that is not covered byphotoengraving pattern 403 andside wall 1401, under above-mentioned light beam or electron beam irradiation and oxygen generation chemical reaction, make it by nonpolarchemical modification zone 1501 of changing polarity into; Another part PETS layer that is covered byphotoengraving pattern 403 andside wall 1401 then and oxygen generation chemical reaction does not still keep nonpolar state, is called nonpolar notchemical modification zone 1502.

Because first channel width that forms in step 1103 and the step 1104 reduces, correspondingly the width in this step irradiation chemical modification zone of width w in compared to existing technology of formingchemical modification zone 1501 also can reduce.Particularly, the width of first raceway groove that the width w in chemical modification of thepresent invention zone 1501 forms after less than photoetching, the width w scope in chemical modification of the present invention zone is smaller or equal to 60 nanometers (nm).

Step 1006, Figure 16 is the cross-sectional view of thelithography step 1006 of DSA block copolymer of the present invention, as shown in figure 16, strippingphotolithography pattern 403 andside wall 1401.

In this step, strippingphotolithography pattern 403 andside wall 1401 can be with dry etching or wet etchings, concrete, can be with dry etching or wet etching strippingphotolithography pattern 403 andside wall 1401 simultaneously, can also adopt first dry method or wet etching to peel offside wall 1401, again the method for dry method or wet etching strippingphotolithography pattern 403.

Step 1007, Figure 17 as shown in figure 17, has the PETS laminar surface spin coating diblock copolymer of chemical pattern for the cross-sectional view of thelithography step 1007 of DSA block copolymer of the present invention

Present embodiment 1701 is that example describes (PS-b-PMMA) with diblock copolymer poly-(styrene-block-methyl methacrylate), but the PETS laminar surface also can the spin coating other types block copolymer (being triblock copolymer or segmented copolymer).The example of diblock copolymer mainly comprises poly-(styrene-block-methyl methacrylate) (PS-b-PMMA), polyethylene glycol oxide-polyisoprene, polyethylene glycol oxide-polybutadiene, polyethylene glycol oxide-polystyrene, polyethylene glycol oxide-polymethyl methacrylate, the pyridine of polystyrene-poly vinyl pyrrole, polystyrene-poly isoprene (PS-b-PI), polystyrene-poly butadiene, polybutadiene-polyvinyl Pyrrolizidine or polyisoprene-polymethyl methacrylate.The example of triblock copolymer comprises poly-(styrene-block methyl methacrylate-block-ethylene oxide).

In this step, select the chemical functional group (for example chemical functional group of PMMA) of corresponding block polymer according to the width in chemical modification zone, also just require this chemical functional group's length consistent with the width in chemical modification zone or conform to, concrete system of selection is prior art, repeats no more.As seen, because the width in chemical modification of the present invention zone diminishes, caused the reducing of chemical functional group's length of the block polymer selected, concerning the block copolymer with this block copolymer, the domain period L of polymer blocks combination₀Also can correspondingly reduce.The domain period L of the polymer blocks combination of the PS-b-PMMA 1701 that this enforcement is selected₀The domain cycle that must make up less than the polymer blocks of PS-b-PMMA in the prior art.(polymer A: PS and polymer B: ratio PMMA) between about 50: 50 and 60: 40 during volume fraction, the block copolymer that PS-b-PMMA 1701 can form in the subsequent anneal step is combined as laminar structured territory or candy strip alternately when two block polymers among the PS-b-PMMA.

Step 1008, Figure 18～19 are the cross-sectional view of thelithography step 1008 of DSA block copolymer of the present invention, shown in Figure 18～19, wafer annealing, the diblock copolymer self assembly forms two kinds of polymer blocks combinations, and two kinds of polymer blocks combinations are the ordered structure territories with periodic structure.

In this step, wafer is put into carbon disulfide atmosphere (CS2) anneals, the temperature range of annealing be 100 to 300 degrees centigrade (℃), for example 100 ℃, 200 ℃ or 300 ℃, the time range of annealing is 8 to 12 hours, for example 8 hours, 10 hours or 12 hours.Can there be multiple combination concrete annealing temperature and time, for example: carry out annealing in 10 hours under 180 ℃, perhaps carry out earlier 5 hours the annealing first time under 150 ℃, carry out annealing for the second time in 5 hours then under 200 ℃.

In annealing process, be that the self assembly of the diblock copolymer of example is divided into following two stages with PS-b-PMMA 1701:

The generalized section of phase I as shown in figure 18, at first the polarization state that presents of the chemical modification zone of PETS laminar surface is bigger to the compatibility of PMMA, so the chemical modification zone will be preferentially wetting by PMMA, form the PMMA block (PMMA block) 1801 of strip, nonpolar notchemical modification zone 1502 presents the neutral wetting state simultaneously, because this neutral wetting state has the compatibility of being equal to two kinds of polymer (PS/PMMA) of diblock copolymer, and will centered by PMMA matrix (PMMA block), form the PS block (PS block) 1802 of strip in its both sides according to the performance polymer PS of diblock copolymer.

The generalized section of second stage as shown in figure 19, in presenting the not chemical modification zone 1502 of neutral wetting state, the PMMA block 1801 that the phase I forms and PS block 1802 form second raceway groove as spacer region on the surface in chemical modification zone 1502 not.This second raceway groove has following structure: sidewall and bottom surface.Second raceway groove is equivalent to form the substrate surface pattern, and according to the principle of pattern guiding DSA, second raceway groove can influence orientation, ordering and the alignment of the microphase-separated domains of copolymer.In the present embodiment, the bottom surface of second raceway groove is the part in chemical modification zone 1502 not, and entropic force impels the neutral wetting surface in chemical modification zone 1502 not to be subjected to two kinds of polymer blocks wetting of diblock copolymer, produces vertical orientated self assembly form; And the sidewall surfaces of second raceway groove can be subjected to the preferential wetting of the polymer (PS or PMMA) of a certain composition in the block copolymer, thereby can form the polymer blocks of strip during this composition polymer self assembly along the sidewall of second raceway groove.Work as nL₀During=Ls, under chemistry guiding DSA polarity selection and pattern guiding DSA, finally be combined to form the ordered structure territory with periodic structure by PS and two kinds of polymer blocks of PMMA.Wherein, Ls is the width sum of raceway groove bottom surface and spacer interval, L₀Be the domain cycle of polymer blocks combination, n is smaller or equal to 10 integer more than or equal to 2.As shown in figure 18, two kinds of polymer blocks combinations of diblock copolymer self assembly formation are the periodic structure territories that replace candy strip in the present embodiment.

Step 1009, Figure 19 is the cross-sectional view of thelithography step 1009 of DSA block copolymer of the present invention, as shown in figure 19, a kind of polymer blocks of selective removal forms patterned film 1901.

In this step, removing specific a kind of polymer blocks concrete grammar is prior art, repeat no more, the patterned film 1901 that optionally removes 1801 formation of PMMA block in the present embodiment can be used as etch mask, with this etch mask be cover below substrate in manufacturing structure, be applied to the making such as metal wire such as grid and metal level.

Specific embodiment two

Specific embodiment two is identical with the step of specific embodiment one, but in the step of the PETS laminar surface spin coating diblock copolymer with chemical pattern, by the ordered structure territory with periodic structure of block copolymer self assembly formation in the volume fraction proportional control wafer annealing process between the block polymer of adjusting the composition block copolymer and the film form of subsequent pattern film.For example work as two block polymers (polymer A: PS and polymer B: the situation of ratio PMMA) between about 60: 40 and 80: 20 among the PS-b-PMMA, PS-b-PMMA becomes the block copolymer of periodicity hexagon closs packing or honey-comb shape array to make up DSA, and wherein polymer B is the cylinder in the polymer A matrix.Periodically cylindrical structure is grown perpendicular to the direction of substrate parallel reaching.Producing vertical cylindrical body by thermal annealing requires base plate bottom generally block copolymer to be the neutral wetting state.But after dwindling by the substrate surface chemical modification and with the size in chemical modification zone, form the pattern in sparse chemical modification zone on its surface.Subsequently, behind the block copolymer heating anneal, at the ad-hoc location of substrate surface, comprise chemical modification zone and the zone of chemical modification not, form and have periodic cylindrical patterned film.The film of this patterning can be used as etch mask, with this etch mask be cover below substrate in manufacturing structure, be applied to the making such as through hole such as magnetic storage device, metal level.

Above-mentioned specific embodiment one and specific embodiment two are as seen, the present invention proposes a kind of photoetching method by directed self assembly block copolymer, this method is dwindled channel dimensions at the sidewall surfaces formation side wall of the spacer interval of photoengraving pattern, form chemical pattern with photoengraving pattern and side wall as mask irradiation PETS laminar surface, thereby reduce the width in the chemical modification zone in the described chemical pattern, also anneal as the self assembly layer at the PETS laminar surface spin coating block copolymer with chemical pattern then, guide DSA after the specific morphology of substrate surface formation polymer blocks combination based on chemistry, the block copolymer in the chemical modification zone spontaneously is not assembled into the periodic structure territory based on pattern guiding DSA, and removing wherein at last, certain polymer blocks forms patterned film.This method has overcome the lithographic accuracy restriction of photoengraving pattern, has increased pattern density and the precision of the patterned film of the photoetching formation by directed self assembly block copolymer.

The above only is preferred embodiment of the present invention, and is in order to limit the present invention, within the spirit and principles in the present invention not all, any modification of making, is equal to replacement, improvement etc., all should be included within the scope of protection of the invention.

Claims (9)

1. photoetching method by directed self assembly block copolymer, one substrate is provided, deposition phenethyl trichlorosilane PETS layer on the described substrate, apply photoresist on the described PETS layer, described photoresist patterning forms photoengraving pattern after the photoetching, described photoengraving pattern comprises spacer interval and first raceway groove, it is characterized in that, this method also comprises:

Described photoengraving pattern surface deposition cover layer;

The described cover layer of dry etching forms side wall at the spacer interval sidewall of described photoengraving pattern;

Be that mask shines described PETS layer with described photoengraving pattern and side wall, form chemical pattern at described PETS laminar surface, the width in chemical modification zone is less than the width of described first raceway groove in the described chemical pattern;

Peel off described photoengraving pattern and side wall;

Has the PETS laminar surface spin coating block copolymer of chemical pattern as the self assembly layer described;

After the described substrate annealing, the block copolymer self assembly forms the polymer blocks combination, and described polymer blocks combination is the ordered structure territory with periodic structure;

Remove certain polymer blocks and form patterned film.

2. method according to claim 1 is characterized in that, described cover layer is silicon dioxide, silicon nitride, nitrogen doping diamond dust, perhaps amorphous carbon.

3. method according to claim 1 is characterized in that, described stripping photolithography pattern and side wall can be with dry etching or wet etchings.

4. method according to claim 1 is characterized in that, described block copolymer is diblock copolymer, triblock copolymer or segmented copolymer.

5. method according to claim 4, it is characterized in that described diblock copolymer is poly-(styrene-block-methyl methacrylate), polyethylene glycol oxide-polyisoprene, polyethylene glycol oxide-polybutadiene, polyethylene glycol oxide-polystyrene, polyethylene glycol oxide-polymethyl methacrylate, the pyridine of polystyrene-poly vinyl pyrrole, polystyrene-poly isoprene, polystyrene-poly butadiene, polybutadiene-polyvinyl Pyrrolizidine or polyisoprene-polymethyl methacrylate; Described triblock copolymer is poly-(styrene-block methyl methacrylate-block-ethylene oxide).

6. method according to claim 1 is characterized in that, described annealing is carried out in carbon disulfide atmosphere.

7. method according to claim 1 is characterized in that, the temperature range of described annealing is 100 to 300 degrees centigrade, and the time range of described annealing is 8 to 12 hours.

8. method according to claim 1 is characterized in that, the domain period L of the width sum Ls of the described first raceway groove bottom surface and described spacer interval and the combination of described polymer blocks₀Satisfy nL₀=Ls, n are smaller or equal to 10 integer more than or equal to 2.

9. method according to claim 1 is characterized in that, the width range in described chemical modification zone is smaller or equal to 60 interior rice.

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