KR100673107B1 - Method for Forming Pattern for Ion-Implantation of Semiconductor Device - Google Patents

Abstract

The present invention relates to a pattern forming method for an ion implantation process of a semiconductor device, and more particularly, a first photoresist layer and a second photo having different dissolution properties during an ion implantation process for increasing the electrical characteristics (Vt) of a substrate. After the resist layer is sequentially formed on the entire surface of the etched layer pattern, a patterning process is performed to prevent voids from occurring in the photoresist layer, thereby performing a stable subsequent ion implantation process. It is to provide a formation method.

Description

Pattern Forming Method for Ion Implantation Process of Semiconductor Device {Method for Forming Pattern for Ion-Implantation of Semiconductor Device}

1a to 1e is a process chart according to the pattern formation method for a conventional ion implantation process.

FIG. 2 is a SEM photograph of voids generated inside the photoresist layer formed by the FIG. 1C process. FIG.

3 is an NMR graph of a polymer of Example 1. FIG.

Figures 4a to 4f is a process chart according to the pattern forming method for the ion implantation process of the present invention.

FIG. 5 is an SEM photograph of an etched layer pattern in which a first photoresist layer is formed by the FIG. 4B process.

FIG. 6 is a SEM photograph of an etched layer pattern in which a second photoresist layer is formed by the FIG. 4C process. FIG.

FIG. 7 is a SEM photograph of an etched layer pattern in which voids are not generated in the photoresist layer formed by the process of FIG.

<Brief description of the main parts of the drawing>

1, 41: semiconductor substrate 3, 43: etched layer pattern                 

5: photoresist layer 5-1: photoresist pattern

7: void 9, 49: opening

11, 51: formed ion implantation region 13: defects generated during the ion implantation process

45: first photoresist layer 45-1: first photoresist pattern

47: Second Photoresist Layer 47-1: First Photoresist Pattern

The present invention relates to a pattern forming method for an ion implantation process of a semiconductor device, and more particularly, a first photoresist layer and a second photo having different dissolution properties during an ion implantation process for increasing the electrical characteristics (Vt) of a substrate. After the resist layer is sequentially formed on the entire surface of the etched layer pattern, a patterning process is performed to prevent voids from occurring in the photoresist layer, thereby performing a stable subsequent ion implantation process. It is to provide a formation method.

As semiconductor devices become increasingly integrated and densified at present, there is a continuous demand for the development of new methods for increasing the integration of devices. For example, it has been difficult to form a fine pattern by a photo-lithography method using a KrF (248 nm) light source. Thus, a photolithography method using an ArF (193 nm) light source, which is a far infrared light source, has been developed. There is a need for the development of photoresist compositions for ArF light sources suitable for carrying out subsequent processes.                         

In particular, since the semiconductor device is highly integrated, the pattern critical dimension (CD) is reduced, and thus the aspect ratio of the pattern is increased. Thus, only a photoresist composition used in the prior art uniforms narrow spaces between the patterns. It is difficult to landfill.

This disadvantage, after forming a photoresist pattern to expose the substrate by crossing the pattern one by one on a substrate formed with a pattern of 0.1㎛ or less, when used as a mask for the ion implantation process, it is enough to protect the substrate from the ion implantation gas Since a photoresist layer having a sufficient thickness cannot be obtained, it becomes impossible to perform a stable C-halo implantation process on the substrate.

The pattern formation method for the conventional ion implantation process as described above is as shown in Figures 1a to 1e.

Referring to FIG. 1A, an etched layer (not shown) is formed on the semiconductor substrate 1 and then etched to form an etched layer pattern 3.

A photoresist layer 5 is formed on the entire surface including the etched layer pattern 3 of FIG. 1A as shown in FIG. 1B.

The photoresist layer 5 of FIG. 1B is exposed and developed to form the photoresist pattern 5-1 as shown in FIG. 1C. In this case, the photoresist pattern includes an opening 9 in which the etched layer pattern 5-1 is opened one by one.

Using the photoresist pattern 5-1 formed in FIG. 1C as a mask for an ion implantation process, an ion implantation process is performed on the formed opening 9 to form the ion implantation region 11 as shown in FIG. 1D. Form.

Next, the photoresist pattern 5-1 is removed to complete the semiconductor substrate 1 in which the ion implantation regions 11 are formed by crossing the etched layer patterns one by one as shown in FIG. 1E.

In this case, as shown in FIG. 1B, when the photoresist layer is formed on the entire surface of the etched layer pattern having a large aspect ratio or a high level difference, the photoresist layer is not uniformly buried due to the viscosity of the photoresist composition. The voids 7 are generated inside the photoresist layer (see FIG. 2). Such voids 7 are more severely generated as the inside of the pattern is narrower and deeper even when using a high resolution photoresist composition.

When a subsequent ion implantation process is performed on the void-formed photoresist layer as shown in FIG. 1D, since the photoresist layer does not have a thickness sufficient to protect the semiconductor substrate from the ion implantation process gas, The problem arises that the defects of another ion implantation region are formed by affecting the substrate of the unwanted region, which later affects the electrical characteristics of the semiconductor device, thereby lowering the yield of the final semiconductor device.

Recently, an exposure apparatus having a high numerical aperture (NA) is used to form an ultra-fine pattern. A fine pattern having a higher aspect ratio is formed by a depth of focus (DOF). It is more difficult to form the photoresist layer, and the degree of generation of voids inside the photoresist layer is further intensified.

Accordingly, the present inventors have completed the present invention by developing a new concept of method that can overcome the above-mentioned problems without developing a photoresist composition having new physical properties or expensive equipment.

The present invention is formed as a mask pattern for ion implantation after forming a photoresist layer in a two-layer structure in the space between the etched layer pattern in order to prevent the generation of voids in the photoresist layer to perform a stable subsequent ion implantation process It is an object of the present invention to provide a pattern forming method for an ion implantation process of a semiconductor device.

In the present invention to achieve the above object

Forming an etched layer pattern on the semiconductor substrate;

Forming a first photoresist layer on the entire surface of the etched layer pattern;

Filling the etched layer pattern by forming a second photoresist layer on the first photoresist layer with a photoresist composition having different dissolution properties from the first photoresist layer;

Forming a two-layer photoresist pattern including an opening in which the etched layer pattern is opened one by one by performing an exposure and development process on the formed two-layer photoresist layer; And

Provided is a pattern forming method for an ion implantation process of a semiconductor device comprising the step of performing an ion implantation process on the exposed semiconductor substrate using the photoresist pattern as an ion implantation mask.

At this time, the first photoresist layer is formed to a thickness of 50nm to 800nm, preferably 100nm to 300nm from the substrate.

Further, after the forming of the first photoresist layer and after the forming of the second photoresist layer, at a temperature above the glass transition temperature, for example, 130 to 180 ° C., for each layer or one layer. The method may further include baking.

The first photoresist layer and the second photoresist layer may be formed using any photoresist composition having different dissolution properties. For example, the first photoresist layer may be a general organic solvent, for example, A photoresist composition comprising a low molecular material having physical properties dissolved in propylene glycol methyl ether acetate (PGMEA) or ethyl lactate is used, and the second photoresist layer is a polymer material that is dissolved in a butanol solvent. Can be. In this case, the order of the photoresist composition for forming the first photoresist layer and the second photoresist layer may be reversely performed.

Hereinafter, the present invention will be described in detail with reference to FIGS. 4A to 4E.

Referring to FIG. 4A, an etched layer (not shown) is formed on the semiconductor substrate 41 and then etched to form an etched layer pattern 43.

In this case, the width of the etched layer pattern is 10 to 150 nm, and the space width between the patterns is 10 to 150 nm.                     

After the first photoresist layer 45 is formed on the entire surface including the etched layer pattern 43 as shown in FIG. 4A, as shown in FIG. 4B, the first photoresist layer is 130-180 ° C. as an optional process. Bake at 100 to 150 seconds, preferably 110 to 130 seconds, preferably at 150 to 160 ° C (see FIG. 5).

The first photoresist layer is formed to a thickness of 50 nm to 800 nm, preferably 100 nm to 300 nm, from the substrate. In this case, the first photoresist layer may be any general photoresist composition, preferably a chemically amplified photoresist composition.

As shown in FIG. 4C, the second photoresist layer 47 is formed on the first photoresist layer 45 formed in FIG. 4B to fill the pattern. Bake at a temperature above the glass transition temperature (see FIG. 6).

In this case, the second photoresist layer may be formed using any material having different solubility properties from the first photoresist layer. Preferably, the second photoresist layer includes a photoresist including a polymer material and butanol dissolved in butanol. It is formed using the composition. The polymer material includes a compound represented by the following Chemical Formula 1, preferably a poly (t-butyl acrylate / methyl methacrylate) polymer.                     

[Formula 1]

Where

R ₁ is an acid sensitive protecting group,

R ₂ is C ₁ to C ₁₀ linear or branched alkyl,

The relative ratio of n: m is 1-99: 99-1 mol%.

In this case, the acid-sensitive protecting group is a group that can be detached by the acid, and determines whether the PR material is dissolved in the alkaline developer. That is, when an acid sensitive protecting group is attached, the PR material is suppressed from being dissolved by the alkaline developer, and when the acid sensitive protecting group is released by the acid generated by exposure, the PR material can be dissolved in the developing solution. Such acid-sensitive protecting groups can be any one which can play such a role, for example US 5,212,043 (May 18, 1993), WO 97/33198 (September 12, 1997), WO 96/37526 (Nov. 28, 1996), EP 0 794 458 (October 10, 1997) EP 0 789 278 (August 13, 1997), US 5,750,680 (May 12, 1998), US 6,051,678 (April 18, 2000) , GB 2,345,286 A (July 5, 2000), US 6,132,926 (October 17, 2000), US 6,143,463 (Nov. 7, 2000), US 6,150,069 (November 21, 2000), US 6.180.316 B1 (2001. 1. 30), US 6,225,020 B1 (May 1, 2001), US 6,235,448 B1 (May 22, 2001) and US 6,235,447 B1 (May 22, 2001) and the like, preferably t -butyl, Tetrahydropyran-2-yl, 2-methyl tetrahydropyran-2-yl, tetrahydrofuran-2-yl, 2-methyl tetrahydrofuran-2-yl, 1-methoxypropyl, 1-methoxy-1 -Methylethyl, 1-ethoxypropyl, 1-ethoxy-1-methylethyl, 1-methoxyethyl, 1-ethoxyethyl, t -butoxyethyl, 1-isobutoxyethyl or 2-acetylment-1 -Work Etc. can be used.

The photoresist composition of the first photoresist layer and the second photoresist layer may further include a photoacid generator and a solvent.

The photoacid generator may be used as long as the compound can generate an acid by light, US 5,212,043 (May 18, 1993), WO 97/33198 (September 12, 1997), WO 96/37526 (1996. 11.28), EP 0794458 (September 10, 1997), EP 0789278 (August 13, 1997), US 5,750,680 (May 12, 1998), US 6,051,678 (April 18, 2000), GB 2,345,286 A (2000) 7. 5), US 6,132,926 (October 17, 2000), US 6,143,463 (11/7/2000), US 6,150,069 (11/21/2000), US 6.180.316 B1 (January 30, 2001), US 6,225,020 B1 (May 1, 2001), US 6,235,448 B1 (May 22, 2001), and US 6,235,447 B1 (May 22, 2001) and the like, and mainly sulfur-based or onium salt-based compounds are used. In particular, low absorbance at 157 nm and 193 nm phthalimidotrifluoromethanesulfonate, dinitrobenzyltosylate, n-decyl disulfone, naphthylimido triple fluoro Naphthylimido trifluoromethane sulfonate, diphenylurido salt hexafluorophosphate, diphenylurido salt hexafluoro arsenate, diphenylurido salt hexafluoro antimonate, diphenylparamethoxyphenylsulfonium triflate, diphenyl Paratoluenylsulfonium triflate, diphenylparaisobutylphenylsulfonium triflate, triphenylsulfonium hexafluoro arsenate, triphenylsulfonium hexafluoro antimonate, triphenylsulfonium triflate, dibutyl Mine selected from the group consisting of naphthylsulfonium triflate and triphenylsulfonium nonaplate Available antibiotics, and it is used in a proportion of 0.05 to 10% parts by weight based on 100 parts by weight of the photoresist polymer.

In addition, the solvent included in the photoresist composition is preferably diethylene glycol diethyl ether, ethyl-3-ethoxypropionate, methyl 3-methoxy propionate, cyclonehexanone, propylene glycol methyl ether acetate, n-heptanone, ethyl lactate, cyclonepentanone, triethanol amine and the like are used.

Exposure and development of the two-layer photoresist layers 45 and 47 formed in FIG. 4C are performed to form two-layer photoresist patterns 45-1 and 47-1 as shown in FIG. 4D. In this case, the photoresist pattern includes an opening 49 in which the etched layer pattern 43 is opened one by one.

In this case, the exposure process may use not only ArF, but also KrF, Extreme Ultra Violet (EUV), Vacuum Ultra Violet (VUV), E-beam, X-ray, or ion beam, and exposure of 1 to 100 mJ / cm ² . It is preferably carried out with energy. The development is carried out using an alkaline developer, for example 0.01 to 5 wt% of a TMAH aqueous solution.

Next, an ion implantation process is performed on the formed openings 49 using the two-layer photoresist patterns 45-1 and 47-1 formed in FIG. 4D as masks for an ion implantation process, as shown in FIG. 4E. An ion implantation region 51 as is formed.

The ion implantation process is performed by an intermediate implantation method of 50 KeV, dose = 2 × 10 ¹³ using bromine (Br) and boron difluoride (BF ₂ ) ions.

Then, the two-layer photoresist patterns 45-1 and 47-1 of FIG. 4E are removed with an alkaline developer, and the semiconductor substrate on which the ion implantation regions 51 are formed by crossing the etching layer patterns one by one as shown in FIG. 4F. 41 is manufactured (see FIG. 7).

In addition, the present invention provides a semiconductor device manufactured using the pattern formation method for the above-described ion implantation process.

Hereinafter, the present invention will be described in detail by examples. However, the examples are only for exemplifying the present invention and the present invention is not limited by the following examples.

I. Preparation of Photoresist Polymer

Example 1.

t-butyl acrylate (14 g), methyl methacrylate (6 g) and 2,2'-azobisisobutyronitrile (AIBN) (0.8 g) were polymerized in PGMEA (100 g) at 60 DEG C for 6 hours. The mixture was distilled under reduced pressure, and the polymer was precipitated, filtered and dried in hexane to obtain a poly (t-butyl acrylate / methyl methacrylate) polymer (8 g) (see NMR in FIG. 3).

Analytical Values for the Poly (t-butyl Acrylate / Methyl Methacrylate) Polymer

¹ H NMR (CD ₃ COD ₃ ) 3.6-3.8 ppm (d, 3 H, -O CH ₃ ),

1.4-1.6 ppm (s, 9H , -C- (CH ₃ ) ₃ ).

II. Preparation of Photoresist Composition

Example 2.

The polymer (1 g) of Example 1, triphenylsulfonium nonaplate (0.03 g) and triethanol amine (0.0024 g), which are photoacid generators, were dissolved in butanol (20 g) and filtered through a 0.01 μm filter to obtain a photoresist composition.

III. Form photoresist pattern

Example 3.

A first photoresist composition (A52T3; Kumho Petrochemical) dissolved in ethyl lactate was formed on the substrate on which the etching layer pattern of 0.1 μm or less was formed to a thickness of 200 nm, and then 120 seconds in an oven or hot plate at 155 ° C. Soft baking was performed to form the first photoresist layer (see FIG. 5).

The photoresist composition of Example 2 was spin-coated to fill the etched layer pattern on the first photoresist layer, and then the first and second photoresist layers were soft baked for 120 seconds in an oven or a hot plate at 150 ° C. This sequentially formed photoresist layer of two-layer structure was formed (see Fig. 6).                     

In the exposure and development process for the two-layer photoresist layer, a two-layer photoresist pattern including an opening in which the etched layer pattern is crossed one by one is formed, and then 50KeV and dose (Dose) Bromine (Br) ions were implanted by an intermediate implantation method of = 2 × 10 ¹³ .

The substrate subjected to the ion implantation process was immersed in a 2.38wt% TMAH aqueous solution for 40 seconds and developed to prepare a semiconductor substrate including a 0.08 μm L / S etched layer pattern having ion implantation regions therebetween (see FIG. 7). ).

As described above, in the present invention, after forming and patterning a photoresist layer having a two-layer structure by using two types of photoresist compositions having different physical properties during an ion implantation process for enhancing electrical characteristics of a substrate, ion implantation is performed. By using it as a process mask, it is possible to prevent a phenomenon in which voids are generated in the photoresist layer to perform a stable ion implantation process, thereby increasing the final yield of the semiconductor device.

Claims (13)

Forming an etched layer pattern on the semiconductor substrate; Forming a first photoresist layer on the entire surface of the etched layer pattern; Filling the etched layer pattern by forming a second photoresist layer on the first photoresist layer with a photoresist composition having different dissolution properties from the first photoresist layer; Forming a two-layer photoresist pattern including an opening in which the etched layer pattern is opened one by one by performing an exposure and development process on the formed two-layer photoresist layer; And And performing an ion implantation process on the exposed semiconductor substrate using the photoresist pattern as an ion implantation mask. The method of claim 1, And the first photoresist layer is formed to a thickness of 50 nm to 800 nm from the substrate. The method of claim 2, And the first photoresist layer is formed to a thickness of 100 nm to 300 nm from the substrate. The method of claim 1, After the forming of the first photoresist layer and after the forming of the second photoresist layer, the method further comprises baking at a temperature of 130 to 180 ° C. for each layer or one layer. A pattern forming method for an ion implantation process of a semiconductor device. The method of claim 1, The first photoresist layer or the second photoresist layer is formed using a photoresist composition comprising a low molecular material having physical properties dissolved in propylene glycol methyl ether acetate (PGMEA) or ethyl lactate (ethyl lactate) A pattern formation method for an ion implantation process of a semiconductor device. The method of claim 1, The method of claim 1, wherein the first photoresist layer or the second photoresist layer is formed using a photoresist composition comprising a polymer material and butanol dissolved in butanol. The method of claim 6, Method for forming a pattern for the ion implantation process of the semiconductor device, characterized in that the polymer material dissolved in the butanol solvent is a compound represented by the following formula (1): [Formula 1]

(Wherein R ₁ is an acid sensitive protecting group, R ₂ is C ₁ to C ₁₀ linear or branched alkyl, The relative ratio of n: m is 1 to 99:99 to 1 mol%.). The method of claim 7, wherein The compound of Formula 1 is a poly (t-butyl acrylate / methyl methacrylate) polymer, characterized in that the pattern formation method for the ion implantation process of a semiconductor device. The method according to claim 5 or 6, The photoresist composition is a pattern forming method for the ion implantation process of the semiconductor device characterized in that it further comprises a photoacid generator and a solvent. The method of claim 1, The exposure process is a pattern forming method for the ion implantation process of a semiconductor device, characterized in that performed by KrF, ArF, Extreme Ultra Violet (EUV), Vacuum Ultra Violet (VUV), E-beam, X-ray or ion beam. The method of claim 1, The ion implantation process is a pattern forming method for the ion implantation process of the semiconductor device, characterized in that performed using bromine (Br) and boron difluoride (BF ₂ ) ions. The semiconductor device manufactured by the manufacturing method of the semiconductor device containing the method of Claim 1. The method of claim 7, wherein The acid sensitive protecting groups are t -butyl, tetrahydropyran-2-yl, 2-methyl tetrahydropyran-2-yl, tetrahydrofuran-2-yl, 2-methyl tetrahydrofuran-2-yl, 1- Methoxypropyl, 1-methoxy-1-methylethyl, 1-ethoxypropyl, 1-ethoxy-1-methylethyl, 1-methoxyethyl, 1-ethoxyethyl, t -butoxyethyl, 1- A pattern forming method for an ion implantation process of a semiconductor device, characterized in that selected from the group consisting of isobutoxyethyl and 2-acetylment-1-yl.

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