CN103681234A - Method for forming self-alignment duplex pattern - Google Patents

Abstract

A method for forming a self-aligned double pattern, comprising: providing a material layer to be etched; forming a sacrificial photoresist layer on the material layer to be etched; curing the sacrificial photoresist layer; Sacrifice the sidewall surface of the photoresist layer to form a first mask pattern; remove the sacrificial photoresist layer. Since the hardness of the sacrificial photoresist layer increases after the sacrificial photoresist layer is cured, the stress generated by the first mask material layer in the process of forming the first mask pattern will not cause the sacrificial photoresist layer to deform, Make the sidewall of the sacrificial photoresist layer still perpendicular to the surface of the material layer to be etched, so that the sidewall of the first mask pattern subsequently formed on the sidewall surface of the sacrificial photoresist layer is perpendicular to the surface of the material layer to be etched , the sidewall morphology of the etched pattern formed by etching the material layer to be etched finally is better.

Description

Formation method of self-aligned double pattern

technical field

The invention relates to semiconductor technology, in particular to a method for forming a self-aligned double pattern.

Background technique

In the field of semiconductor manufacturing, photoresist materials are used to transfer mask images to one or more material layers, for example, transfer mask images to metal layers, dielectric layers or semiconductor substrates. However, as the feature size of the semiconductor process continues to shrink, it becomes more and more difficult to form a mask pattern with a small feature size in the material layer by using a photolithography process.

In order to improve the integration level of semiconductor devices, various double patterning processes have been proposed in the industry, among which the self-aligned double patterning (Self-Aligned Double Patterning, SADP) process is one of them. 1 to 6 are a method for etching a semiconductor structure using a self-aligned double pattern as a mask in the prior art, specifically including:

1, a semiconductor substrate 10 is provided, a material layer 20 to be etched is formed on the surface of the semiconductor substrate 10, a bottom antireflection layer 40 is formed on the surface of the material layer 20 to be etched, and a bottom antireflection layer 40 is formed on the surface of the semiconductor substrate 10. A photoresist layer 50 is formed on the surface;

Please refer to FIG. 2, the photoresist layer is exposed and developed to form a sacrificial photoresist layer 55, and the bottom antireflection layer is etched using the sacrificial photoresist layer 55 as a mask to form a sacrificial bottom antireflection layer. reflective layer 45;

Referring to FIG. 3 , a hard mask layer 60 is formed on the surface of the material layer to be etched 20 , the sacrificial photoresist layer 55 and the sidewall surface of the sacrificial bottom antireflection layer 45 , and the top surface of the sacrificial photoresist layer 55 ;

Please refer to FIG. 4, the hard mask layer is etched back until the surface of the material layer 20 to be etched and the top surface of the sacrificial photoresist layer 55 are exposed. In the sacrificial photoresist layer 55, sacrificing the side wall surface of the bottom anti-reflection layer 45 to form the side wall 65;

Please refer to FIG. 5, removing the sacrificial photoresist layer and the sacrificial bottom anti-reflection layer;

Referring to FIG. 6 , the material layer 20 to be etched is etched using the sidewall 65 as a mask.

For more information about the self-aligned double patterning process, please refer to the US patent document with publication number US2009/0146322A1.

However, the inventors found that the sidewall morphology of the etched pattern formed by etching the material layer to be etched by the above method is relatively poor.

Contents of the invention

The problem to be solved by the present invention is to provide a method for forming a self-aligned double pattern, and the etched pattern finally formed by the method has better sidewall morphology.

In order to solve the above problems, the technical solution of the present invention provides a method for forming a self-aligned double pattern, comprising: providing a material layer to be etched; forming a sacrificial photoresist layer on the material layer to be etched; curing the sacrificial photoresist layer; forming a first mask pattern on the sidewall surface of the sacrificial photoresist layer; removing the sacrificial photoresist layer.

Optionally, the curing process is an ion implantation curing process, and the photoresist on the top and side walls of the sacrificial photoresist layer is converted into a cured photoresist shell by using the ion implantation curing process.

Optionally, the ion implanted in the ion implantation curing process is one or a combination of H, B, BF ₂ , BF ₃ , BF ₄ , P, As, In, C, Ge.

Optionally, in the ion implantation curing process, the implantation dose ranges from 10E13atom/cm ² to 10E16atom/cm ² , the implantation energy ranges from 1KeV to 500KeV, and the implantation angle ranges from -70° to 70°.

Optionally, the process of forming the sacrificial photoresist layer includes: forming a photoresist layer on the surface of the material layer to be etched, and exposing and developing the photoresist layer to form a sacrificial photoresist layer.

Optionally, the process of forming the first mask pattern includes: forming a first mask material layer on the surface of the material layer to be etched and the sacrificial photoresist layer; etching to form a first mask pattern on the sidewall of the sacrificial photoresist layer.

Optionally, the process of forming the sacrificial photoresist layer includes: forming a bottom antireflection layer on the surface of the material layer to be etched, forming a photoresist layer on the surface of the bottom antireflection layer, The adhesive layer is exposed and developed to form a sacrificial photoresist layer.

Optionally, the process of forming the first mask pattern includes: forming a first mask material layer on the surface of the bottom anti-reflection layer and the sacrificial photoresist layer, and etching back the first mask material layer etch to form a first mask pattern on the sidewall of the sacrificial photoresist layer.

Optionally, the process of forming the sacrificial photoresist layer includes: forming a bottom antireflection layer on the material layer to be etched, forming a photoresist layer on the surface of the bottom antireflection layer, Expose and develop the adhesive layer to form a sacrificial photoresist layer, and use the sacrificial photoresist layer as a mask to etch the bottom antireflection layer to form a sacrificial bottom antireflection layer.

Optionally, the process of forming the sacrificial photoresist layer includes: forming a developer-soluble bottom antireflection layer on the material layer to be etched, and forming a photoresist layer on the surface of the bottom antireflection layer and exposing and developing the bottom anti-reflection layer and the photoresist layer to form a sacrificial bottom anti-reflection layer and a sacrificial photoresist layer on the surface of the sacrificial bottom anti-reflection layer.

Optionally, the process of forming the first mask pattern includes: on the surface of the material layer to be etched, on the sidewall surface of the sacrificial bottom anti-reflection layer and the sacrificial photoresist layer, on the top surface of the sacrificial photoresist layer A first mask material layer is formed, the first mask material layer is etched back, and a first mask pattern is formed on the sidewall surfaces of the sacrificial bottom anti-reflection layer and the sacrificial photoresist layer.

Optionally, the material of the first mask pattern is one or more of silicon oxide, silicon nitride, silicon oxynitride, titanium nitride, and tantalum nitride.

Optionally, the method further includes forming a second mask material layer on the surface of the material layer to be etched, and forming a sacrificial photoresist layer on the second mask material layer.

Optionally, after the first mask pattern is formed, the second mask material layer is etched using the first mask pattern as a mask to form a second mask pattern.

Optionally, the first mask pattern is removed, and the material layer to be etched is etched using the second mask pattern as a mask.

Optionally, the material of the second mask material layer is silicon oxide, silicon nitride, silicon carbide, silicon oxynitride, amorphous carbon, polysilicon, hafnium oxide, titanium oxide, zirconium oxide, titanium nitride, nitride One or more of tantalum and titanium.

Optionally, the method further includes: using the first mask pattern as a mask to etch the material layer to be etched.

Compared with the prior art, the present invention has the following advantages:

In the embodiment of the present invention, a sacrificial photoresist layer is formed on the material layer to be etched, ion implantation is performed on the sacrificial photoresist layer, and then a first mask is formed on the side wall surface of the sacrificial photoresist layer. film pattern, after removing the sacrificial photoresist layer, use the first mask pattern to etch the material layer to be etched. Since the hardness of the sacrificial photoresist layer increases after the sacrificial photoresist layer is cured, the stress generated by the first mask material layer in the process of forming the first mask pattern will not cause the sacrificial photoresist layer to deform, Make the sidewall of the sacrificial photoresist layer still perpendicular to the surface of the material layer to be etched, so that the sidewall of the first mask pattern subsequently formed on the sidewall surface of the sacrificial photoresist layer is perpendicular to the surface of the material layer to be etched , the sidewall morphology of the etching pattern formed by etching the material layer to be etched finally is better.

Description of drawings

1 to 6 are schematic cross-sectional structural diagrams of a self-aligned double patterning process in the prior art;

7 is a schematic flowchart of a method for forming a self-aligned double pattern according to an embodiment of the present invention;

8 to 17 are schematic cross-sectional structural views of the formation process of the self-aligned double pattern according to the embodiment of the present invention.

Detailed ways

Due to the poor sidewall morphology of the etched pattern formed by etching the material layer to be etched using the above technology, the inventors have found through research that when a hard mask layer is formed on the surface of the sacrificial material layer and the sacrificial photoresist layer , the hard mask layer will produce stress on the sacrificial photoresist layer. Since the hardness of the photoresist layer is not large, the photoresist layer is relatively soft even after pre-baking. The stress generated by the hard mask layer The sacrificial photoresist layer will be deformed to form a trapezoidal sacrificial photoresist layer, so that the sidewall of the sacrificial photoresist layer is not perpendicular to the surface of the material layer to be etched, so that the subsequent formation of the sacrificial photoresist layer The sidewall on the surface of the sidewall of the layer is not perpendicular to the surface of the material layer to be etched, which affects the morphology of the sidewall of the etched pattern formed by etching the material layer to be etched.

For this reason, the present invention proposes a kind of formation method of self-aligned double pattern, forms sacrificial photoresist layer on described to-be-etched material layer, described sacrificial photoresist layer is cured, then on described sacrificial photoresist layer A first mask pattern is formed on the sidewall surface of the photoresist layer, and after the sacrificial photoresist layer is removed, the material layer to be etched is etched using the first mask pattern. Since the hardness of the sacrificial photoresist layer increases after the sacrificial photoresist layer is cured, the stress generated by the first mask material layer in the process of forming the first mask pattern will not cause the sacrificial photoresist layer to deform, Make the sidewall of the sacrificial photoresist layer still perpendicular to the surface of the material layer to be etched, so that the sidewall of the first mask pattern subsequently formed on the sidewall surface of the sacrificial photoresist layer is perpendicular to the surface of the material layer to be etched , the sidewall morphology of the etching pattern formed by etching the material layer to be etched finally is better.

In order to make the above objects, features and advantages of the present invention more comprehensible, specific implementations of the present invention will be described in detail below in conjunction with the accompanying drawings.

In the following description, specific details are set forth in order to provide a thorough understanding of the present invention. However, the present invention can be implemented in many other ways than those described here, and those skilled in the art can make similar extensions without departing from the connotation of the present invention. Accordingly, the invention is not limited to the specific implementations disclosed below.

Please refer to FIG. 7 , which is a schematic flowchart of a method for forming a self-aligned double pattern according to an embodiment of the present invention, specifically including:

Step S101, providing a semiconductor substrate, and forming a material layer to be etched on the surface of the semiconductor substrate;

Step S102, forming a second mask material layer on the surface of the material layer to be etched;

Step S103, forming a bottom antireflection layer on the surface of the second mask material layer, and forming a photoresist layer on the surface of the bottom antireflection layer;

Step S104, exposing and developing the photoresist layer to form a sacrificial photoresist layer;

Step S105, performing ion implantation on the sacrificial photoresist layer, and forming a cured photoresist shell from the photoresist on the top and side walls of the sacrificial photoresist layer;

Step S106, forming a first mask material layer on the surface of the bottom anti-reflection layer and the sacrificial photoresist layer, etching back the first mask material layer, forming the first mask pattern;

Step S107, removing the sacrificial photoresist layer, using the first mask pattern as a mask to etch the bottom anti-reflection layer and the second mask material layer to form a second mask pattern;

Step S108 , removing the first mask pattern, and using the second mask pattern as a mask to etch the material layer to be etched to form an etching pattern.

Specifically, please refer to FIG. 8 to FIG. 17 , which are structural schematic diagrams of the formation process of the self-aligned double pattern according to the embodiment of the present invention.

Referring to FIG. 8 , a semiconductor substrate 100 is provided, and a material layer 110 to be etched is formed on the surface of the semiconductor substrate 100 .

The semiconductor substrate 100 is one of a silicon substrate, a germanium substrate, a silicon germanium substrate, a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GOI) substrate, a glass substrate, and the like. The material layer 110 to be etched is one or more of a silicon oxide layer, a silicon nitride layer, a polysilicon layer, a low-K dielectric material, amorphous carbon, and a metal layer. In this embodiment, the material layer 110 to be etched is a metal layer, and the material of the metal layer is aluminum, and the metal interconnection is formed by etching the metal layer by using the self-aligned double pattern as a mask. In other embodiments, the material layer to be etched may also be a semiconductor substrate, and the semiconductor substrate is etched using the self-aligned double pattern as a mask.

Referring to FIG. 9 , a second mask material layer 120 is formed on the surface of the material layer 110 to be etched.

The second mask material layer 120 is a single-layer structure or a multi-layer stack structure, and the material of the second mask material layer 120 is silicon oxide, silicon nitride, silicon carbide, silicon oxynitride, amorphous carbon, polysilicon , hafnium oxide, titanium oxide, zirconium oxide, titanium nitride, tantalum nitride, and titanium, and the process for forming the second mask material layer 120 is a chemical vapor deposition process or a physical vapor deposition process. The material of the second mask material layer 120 is different from the material of the material layer 110 to be etched, and both have a high etching selectivity ratio, so that the second mask formed by the second mask material layer 120 subsequently When the material layer 110 to be etched is etched, the loss of the second mask pattern is small, which is beneficial to control the shape and size of the finally formed etched pattern. And because the upper end of the first mask pattern formed by subsequent etching back is often not a regular rectangle, but has a certain curvature, directly using the first mask pattern as a mask to etch the material layer to be etched will affect the final formation. Therefore, in this embodiment, a second mask material layer 120 is formed on the surface of the material layer 110 to be etched, and the second mask material layer 120 is used to form a second mask subsequently. After the film pattern is removed, the first mask pattern located on its surface is removed, and the second mask pattern whose upper end shape is a regular rectangle is used as a mask to etch the material layer to be etched, which is beneficial to control the final formed etching pattern. The shape of the eclipse pattern. And in this embodiment, the second mask material layer 120 includes an amorphous carbon layer and a silicon oxide layer located on the surface of the amorphous carbon layer, since the dry etching process etches the amorphous carbon layer The shape of the side wall of the amorphous carbon layer is better, and the etching selection of the silicon oxide layer and the metal layer is relatively large, which is beneficial to etching the metal layer with a larger thickness.

Referring to FIG. 10 , a bottom antireflection layer 130 is formed on the surface of the second mask material layer 120 , and a photoresist layer 140 is formed on the surface of the bottom antireflection layer 130 .

In order to prevent the exposed light from being reflected at the interface between the photoresist layer and the substrate after passing through the photoresist layer, so that the photoresist cannot be uniformly exposed, in this embodiment, the second mask material layer 120 A bottom anti-reflection layer (BARC) 130 is formed on the surface first, and then a photoresist layer 140 is formed on the surface of the bottom anti-reflection layer 130 . In other embodiments, a photoresist layer may also be directly formed on the surface of the second mask material layer.

In this embodiment, the bottom anti-reflection layer 130 is an inorganic bottom anti-reflection layer, such as silicon nitride, silicon oxynitride, and the like. In other embodiments, the bottom anti-reflection layer may also be an organic bottom anti-reflection layer, such as polyimide.

The inorganic bottom anti-reflective layer and the organic bottom anti-reflective layer are insoluble in the developer after the exposure process. In other embodiments, the bottom anti-reflective layer used can also be dissolved in the developer after exposure, so that the one-step exposure and development process can simultaneously Forming a patterned sacrificial bottom anti-reflection layer and a sacrificial photoresist layer on the surface of the sacrificial bottom anti-reflection layer saves a process of etching and removing the sacrificial bottom anti-reflection layer.

In this embodiment, the process for forming the inorganic bottom anti-reflection layer is a chemical vapor deposition process or physical vapor deposition process, and the process for forming the photoresist layer is a spin coating process.

In other embodiments, the process of forming the bottom anti-reflection layer may also be a spin coating process.

In other embodiments, instead of forming a second mask material layer on the surface of the material layer to be etched, a bottom antireflection layer is directly formed on the surface of the material layer to be etched, and a bottom antireflection layer is formed on the surface of the bottom antireflection layer. the photoresist layer, and use the first mask pattern subsequently formed on the surface of the material layer to be etched as a mask to etch the material layer to be etched.

Referring to FIG. 11 , the photoresist layer 140 (see FIG. 10 ) is exposed and developed to form a patterned sacrificial photoresist layer 145 on the surface of the bottom antireflection layer 130 .

After the photoresist layer 140 is exposed, the photoresist layer in the exposed area is developed with a developing solution. In this embodiment, the developing solution is tetramethylammonium hydroxide solution. In this embodiment, after the patterned sacrificial photoresist layer 145 is formed, a first mask pattern is formed on the sidewall of the patterned sacrificial photoresist layer 145 .

In other embodiments, after the patterned sacrificial photoresist layer is formed, the bottom antireflective layer is etched using the patterned sacrificial photoresist layer as a mask to form a patterned sacrificial photoresist layer. The bottom anti-reflection layer, followed by forming a first mask pattern on the side wall surfaces of the sacrificial bottom anti-reflection layer and the sacrificial photoresist layer.

In other embodiments, when the bottom anti-reflection layer is dissolved in the developer solution after exposure, the photoresist layer and the bottom anti-reflection layer are exposed and developed to obtain a patterned sacrificial bottom anti-reflection layer and the Sacrifice the sacrificial photoresist layer on the surface of the bottom antireflection layer, and subsequently form a first mask pattern on the sidewall surfaces of the sacrificial bottom antireflection layer and the sacrificial photoresist layer.

Referring to FIG. 12 , ion implantation is performed on the sacrificial photoresist layer 145 , and the photoresist on the top and sidewalls of the sacrificial photoresist layer 145 is formed into a cured photoresist shell 146 .

The specific parameters of the ion implantation curing process include: the implanted ions are one or a combination of H, B, BF ₂ , BF ₃ , BF ₄ , P, As, In, C, Ge, and the ion implanted The dose range is 10E13atom/cm ² ~10E16atom/cm ² , the ion implantation energy range is 1KeV~500KeV, and the implantation angle range is -70~70 degrees, so that not only on the top of the sacrificial photoresist layer 145, but also on the top of the sacrificial photoresist layer 145 The sidewalls of the resist layer 145 form a cured photoresist shell 146 . The implanted ions will re-crosslink with the photoresist molecules, so that the photoresist will be cured, and the large dose of implanted ions will increase the temperature of the surface of the sacrificial photoresist, so that the sacrificial photoresist of the ion implantation will The resist layer is dehydrated and even carbonized. Since the hardness of the carbonized photoresist is far greater than that of the photoresist without ion implantation, a cured photoresist shell 146 is formed on the top and sidewalls of the sacrificial photoresist layer, and the first mask formed subsequently The stress generated by the material layer will not deform the cured photoresist shell, and will not cause the sidewall deformation of the sacrificial photoresist layer to tilt or wrinkle, and the sidewall of the sacrificial photoresist layer will still being flat and smooth and perpendicular to the surface of the material layer to be etched, so that the sidewall of the first mask pattern subsequently formed on the side wall of the sacrificial photoresist layer is also flat and smooth and perpendicular to the surface of the material layer to be etched.

Referring to FIG. 13 , a first mask material layer 150 is formed on the surface of the bottom anti-reflection layer 130 , the sidewall and the top surface of the sacrificial photoresist layer 145 .

The material of the first mask material layer 150 is one or more of silicon oxide, silicon nitride, silicon oxynitride, titanium nitride, and tantalum nitride. The material of the first mask material layer 150 is different from the material of the second mask material layer 120, both of which have a high etching selectivity ratio, so that the subsequent first mask formed by using the first mask material layer 150 When the film pattern etches the second mask material layer 120, the loss of the first mask pattern is small, which is beneficial to control the shape and size of the finally formed etching pattern.

In other embodiments, when the bottom antireflection layer is directly formed on the surface of the material layer to be etched, the material of the first mask material layer is different from the material layer of the material layer to be etched, and both have high The etching selectivity ratio makes the loss of the first mask pattern when the first mask pattern formed by the first mask material layer is used to etch the material layer to be etched subsequently is small, which is beneficial to control the final formed etching pattern. The shape and size of the eclipse pattern.

Since the first mask material layer 150 is used to form the first mask pattern of the self-aligned double pattern, the width of the first mask pattern depends on the first mask of the sidewall surface of the sacrificial photoresist layer 145. The thickness of the film material layer 150, therefore, by controlling the thickness of the first mask material layer 150, the width of the finally formed etching pattern can be controlled. The process of the first mask material layer formed in the embodiment of the present invention is an atomic layer deposition process, a low-pressure chemical vapor deposition process, or a sub-atmospheric pressure chemical vapor deposition process. Since the deposition rates of the above-mentioned several deposition processes are relatively slow, the formed The uniformity of the first mask material layer is better, the sidewall of the first mask material layer 150 located on the sidewall surface of the sacrificial photoresist layer 145 is flat and vertical, and the shape is better, so that the first mask formed subsequently The shape of the sidewall of the film pattern is better, and when the second mask material layer or the material layer to be etched is etched using the first mask pattern as a mask, the shape of the pattern formed by etching is better.

Please refer to FIG. 14 , etch back the first mask material layer 150 (refer to FIG. 13 ) until the surface of the bottom anti-reflection layer 130 is exposed, which is located on the sidewall surface of the sacrificial photoresist layer 145. The first mask material layer 150 forms a first mask pattern 155 .

The width of the first mask pattern 155 corresponds to the thickness of the first mask material layer 150 . When the shape of the sacrificial photoresist layer 145 in a top view is elongated, the shape of the first mask pattern 155 is a ring mask pattern surrounding the sacrificial photoresist layer 145. In this embodiment, Since the final etching pattern is a metal interconnection line, after removing the sacrificial bottom anti-reflection layer and sacrificial photoresist layer, the photoresist is used to cover the first mask pattern corresponding to the strip-shaped middle area, Exposing the first mask pattern corresponding to the two ends of the long strip, using the photoresist as a mask to remove the first mask pattern corresponding to the two ends of the long strip, so that the first mask pattern becomes A straight or polyline for a bar.

Referring to FIG. 15 , the sacrificial photoresist layer 145 (refer to FIG. 13 ) is removed by an ashing process.

Since the material of the sacrificial photoresist layer is composed of organic matter composed of C, O, H, N and other elements, the reaction gas of the ashing process is O ₂ , and the oxygen is plasmatized, and the oxygen The plasma reacts with the carbonized or non-carbonized sacrificial photoresist layer 145 to form volatile carbon monoxide, carbon dioxide, water and other main products, thereby removing the sacrificial photoresist layer 145 . In other embodiments, the reaction gas of the ashing process may also include N ₂ or H _{2 ,} etc., and the N ₂ or H ₂ is beneficial to improve the ability to remove the sacrificial photoresist layer and residual polymer.

In other embodiments, the sacrificial photoresist layer may also be removed by using a wet etching process or a dry etching process.

Since the material of the bottom anti-reflection layer in the embodiment of the present invention is an inorganic bottom anti-reflection layer, it will not be removed by the ashing process, so that the ashing process only removes the sacrificial photoresist layer 145 .

In other embodiments, when the first mask pattern is formed on the sacrificial bottom antireflection layer and the sidewall of the sacrificial photoresist layer, the ashing process, wet etching process or dry etching process is used to remove The sacrificial bottom anti-reflection layer and the sacrificial photoresist layer.

Please refer to FIG. 16 , using the first mask pattern 155 as a mask, perform dry etching on the bottom anti-reflective layer 130 (refer to FIG. 15 ) and the second mask material layer 120 (refer to FIG. 15 ), A second mask pattern 125 is formed. Since the upper end of the first mask pattern 155 formed by etching back is often not a regular rectangle, it has a certain radian, and directly using the first mask pattern as a mask to etch the material layer to be etched will affect the final formed. The topography of the sidewall of the etched pattern, therefore, in this embodiment, after forming the second mask pattern 125, remove the first mask pattern 155 and the remaining bottom anti-reflection layer located on its surface, so that the shape of the upper end The second mask pattern 125 which is a regular rectangle is a mask, and the material layer 110 to be etched is etched, which is beneficial to control the shape of the etched pattern finally formed.

Please refer to FIG. 17 , remove the first mask pattern 155 (refer to FIG. 16 ) and the remaining bottom anti-reflective layer, and use the second mask pattern 125 as a mask to process the material layer 110 to be etched. Etching to form an etching pattern 115 of a self-aligned double pattern. In this embodiment, the process of removing the first mask pattern 155 and the remaining bottom anti-reflection layer is wet etching. Since the width of the etching pattern 115 is determined according to the thickness of the first mask material layer, the thickness of the first mask material layer can be smaller than the minimum size of the photolithography and etching processes of the existing technology, so that the etching The width of the etching pattern 115 is smaller than that of the pattern formed by the photolithography process, which is beneficial to improve the integration degree of the integrated circuit.

To sum up, in the embodiment of the present invention, a sacrificial photoresist layer is formed on the material layer to be etched, and the sacrificial photoresist layer is ion-implanted and cured, and then formed on the sidewall surface of the sacrificial photoresist layer. A first mask pattern, after removing the sacrificial photoresist layer, use the first mask pattern to etch the material layer to be etched. Since the hardness of the sacrificial photoresist layer increases after the sacrificial photoresist layer is cured, the stress generated by the first mask material layer in the process of forming the first mask pattern will not cause the sacrificial photoresist layer to deform, Make the sidewall of the sacrificial photoresist layer still perpendicular to the surface of the material layer to be etched, so that the sidewall of the first mask pattern subsequently formed on the sidewall surface of the sacrificial photoresist layer is perpendicular to the surface of the material layer to be etched , the sidewall morphology of the etching pattern formed by etching the material layer to be etched finally is better.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention, and any person skilled in the art can use the methods disclosed above and technical content to analyze the present invention without departing from the spirit and scope of the present invention. Possible changes and modifications are made in the technical solution. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention, which do not depart from the content of the technical solution of the present invention, all belong to the technical solution of the present invention. protected range.

Claims (17)

1. a formation method for autoregistration double-pattern, is characterized in that, comprising:

Material layer to be etched is provided;

On described material layer to be etched, form and sacrifice photoresist layer;

Described sacrifice photoresist layer is cured;

Sidewall surfaces at described sacrifice photoresist layer forms the first mask pattern;

Remove described sacrifice photoresist layer.

2. the formation method of autoregistration double-pattern as claimed in claim 1, it is characterized in that, described curing process is Implantation curing process, utilizes described Implantation curing process that the photoresist of top and sidewall in sacrifice photoresist layer is become and solidifies photoresist shell.

3. the formation method of autoregistration double-pattern as claimed in claim 2, is characterized in that, the ion injecting in described Implantation curing process is H, B, BF ₂, BF ₃, BF ₄, P, As, In, C, wherein one or more of Ge combination.

4. the formation method of autoregistration double-pattern as claimed in claim 3, is characterized in that, the dosage range injecting in described Implantation curing process is 10E13atom/cm ²~ 10E16atom/cm ², the energy range of injection is 1KeV ~ 500KeV, the angular range of injection is-70 degree ~ 70 degree.

5. the formation method of autoregistration double-pattern as claimed in claim 1, it is characterized in that, the technique that forms described sacrifice photoresist layer comprises: in described material surface to be etched, form photoresist layer, described photoresist layer is carried out to exposure imaging, form and sacrifice photoresist layer.

6. the formation method of autoregistration double-pattern as claimed in claim 5, it is characterized in that, the technique that forms described the first mask pattern comprises: on described material layer to be etched, sacrifice photoresist layer surface, form the first mask material layer, described the first mask material layer is returned to etching, at described sacrifice photoresist layer sidewall, form the first mask pattern.

7. the formation method of autoregistration double-pattern as claimed in claim 1, it is characterized in that, the technique that forms described sacrifice photoresist layer comprises: in described material surface to be etched, form bottom anti-reflection layer, on described bottom anti-reflection layer surface, form photoresist layer, described photoresist layer is carried out to exposure imaging, form and sacrifice photoresist layer.

8. the formation method of autoregistration double-pattern as claimed in claim 7, it is characterized in that, the technique that forms described the first mask pattern comprises: on described bottom anti-reflection layer, sacrifice photoresist layer surface, form the first mask material layer, described the first mask material layer is returned to etching, at described sacrifice photoresist layer sidewall, form the first mask pattern.

9. the formation method of autoregistration double-pattern as claimed in claim 1, it is characterized in that, the technique that forms described sacrifice photoresist layer comprises: on described material layer to be etched, form bottom anti-reflection layer, on described bottom anti-reflection layer surface, form photoresist layer, described photoresist layer is carried out to exposure imaging, form and sacrifice photoresist layer, the described sacrifice photoresist layer of take is mask, described bottom anti-reflection layer is carried out to etching, form and sacrifice bottom anti-reflection layer.

10. the formation method of autoregistration double-pattern as claimed in claim 1, it is characterized in that, the technique that forms described sacrifice photoresist layer comprises: on described material layer to be etched, form the bottom anti-reflection layer that dissolves in developer solution, on described bottom anti-reflection layer surface, form photoresist layer, described bottom anti-reflection layer and photoresist layer are carried out to exposure imaging, form the sacrifice photoresist layer of sacrificing bottom anti-reflection layer and being positioned at described sacrifice bottom anti-reflection layer surface.

The formation method of 11. autoregistration double-patterns as described in claim 9 or 10, it is characterized in that, the technique that forms described the first mask pattern comprises: the sidewall surfaces at described material surface to be etched, sacrifice bottom anti-reflection layer and sacrifice photoresist layer forms the first mask material layer, sacrifice the top surface of photoresist layer, described the first mask material layer is returned to etching, in described sacrifice bottom anti-reflection layer and the sidewall surfaces of sacrificing photoresist layer, form the first mask pattern.

The formation method of 12. autoregistration double-patterns as claimed in claim 1, is characterized in that, the material of described the first mask pattern is silica, silicon nitride, silicon oxynitride, titanium nitride, wherein one or more of tantalum nitride.

The formation method of 13. autoregistration double-patterns as claimed in claim 1, is characterized in that, also comprises, in described material surface to be etched, forms the second mask material layer, forms and sacrifice photoresist layer on described the second mask material layer.

The formation method of 14. autoregistration double-patterns as claimed in claim 13, is characterized in that, forms after described the first mask pattern, and described the first mask pattern of take is mask, and described the second mask material layer is carried out to etching, forms the second mask pattern.

The formation method of 15. autoregistration double-patterns as claimed in claim 14, is characterized in that, removes described the first mask pattern, and described the second mask pattern of take is mask, and described material layer to be etched is carried out to etching.

The formation method of 16. autoregistration double-patterns as claimed in claim 13, it is characterized in that, the material of described the second mask material layer is silica, silicon nitride, carborundum, silicon oxynitride, amorphous carbon, polysilicon, hafnium oxide, titanium oxide, zirconia, titanium nitride, tantalum nitride, wherein one or more of titanium.

The formation method of 17. autoregistration double-patterns as claimed in claim 1, is characterized in that, also comprises, described the first mask pattern of take is mask, and described material layer to be etched is carried out to etching.

Images