JPH117134A - Antireflection layer for manufacturing semiconductor device and manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the upper antireflection coating high in etching-resistance by using constituents comprising a copolymer of indanone or glutarimide and a solvent and an additive sensitizer having an o-diazonaphthoquinone structure. SOLUTION: This upper antireflection coating (TARL) material comprises the indanone or glutarimide copolymer and the solvent immiscible with a resist in the lower layer and the additive sensitizer having an o-diazonaphthoquinone structure. This copolymer is prepared by polymerizing the indanone or glutarimide with acylate methacrylate, vinyl, olefine, epoxy, or alcohol.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to light projection exposure systems and, more particularly, to a top anti-reflective coating for use in a lithographic system.

[0002]

2. Description of the Related Art In the manufacture of semiconductor devices, a photoresist layer is applied directly to a substrate surface or to a layer already formed on the substrate surface. Next, a part of the photoresist is irradiated with UV light in a pattern. Next, a developer is applied to remove the desired photoresist, either irradiated or unirradiated.

Light scattering or interference caused by light reflection from a substrate causes, for example, a pattern conversion difference in an exposed area of a photoresist layer. In other words, the desired dimensions of the illuminated photoresist layer are altered by light reflection from the substrate surface. In some semiconductor devices, slight variations in desired dimensions may be tolerated. However, such fluctuations change the desired characteristics and performance of the semiconductor device, so that there is usually a point where further fluctuations cannot be tolerated. This point where further fluctuation cannot be tolerated is called critical dimension (hereinafter referred to as CD).

Also, in lithographic systems, thin film interference effects result in low CD controllability and low precision alignment. These problems include, for example, the 248 nm KrF excimer laser and ArF
This is more prominent for exposure light having a short wavelength such as 193 nm of an excimer laser.

[0005] Two solutions to suppress thin film interference and reduce light scattering or interference are to use a lower anti-reflective coating (BARL) and an upper anti-reflective coating (TARL). BA
The RL is typically applied to the substrate and baked before applying the photoresist layer. After the photoresist layer is applied, in a realistic BARL process, a pattern is formed in the photoresist by irradiation with DUV light.
Next, the photoresist pattern is continuously transferred to both the BARL and the substrate by reactive ion etching (hereinafter referred to as RIE). After pattern transfer, the desired photoresist and BARL patterns are removed.
Therefore, BARL has a higher light absorption,
Light scattering or interference caused by light reflections on the substrate must be reduced more effectively. However, there are few BARLs available that completely suppress light scattering or interference without reducing the alignment light.

[0006] The TURL is typically spin-coated over the applied photoresist and baked. The pattern is formed simultaneously in both the TAR and the photoresist by DUV light. TAR pattern is
In a realistic TURL process, it is usually completely removed by a developer. Next, the photoresist pattern is transferred to the substrate by RIE. After pattern transfer,
The photoresist pattern is removed. Therefore, T
ARL must be somewhat transparent in order to transmit both incident light and light reflections from the substrate. However, it has a refractive index suitable for the wavelength of the exposure light and has no interaction at the interface between the underlying resist and the TURL itself.
Obtaining an ARL layer is difficult.

In modern lithography, the reduction in photoresist thickness does not change the wavelength of the exposure light and the numerical aperture of the optical device, while at the same time reducing the k ₁ and k ₂ factors in the conventional Rayleigh equation. It is well known that provoking an increased image. On the other hand, it causes more severe thin film interference and requires higher etch selectivity. In order to solve the problems associated with such conventional single-layer resist technology, either the photoresist or the TURL is required to have a higher etching resistance than previously expected.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an antireflection layer for manufacturing a semiconductor device which has a refractive index suitable for the wavelength of exposure light and has no interaction at the interface with a lower resist. I do. Another object of the present invention is to provide an antireflection layer for manufacturing a semiconductor device having high etching resistance.

Another object of the present invention is to provide an antireflection layer for manufacturing a semiconductor device and a method for manufacturing a semiconductor device, which significantly reduce the fluctuation of CD in the irradiated photoresist layer.

[0010]

According to the present invention, there is provided a TAR layer comprising:
It has a refractive index suitable for the wavelength of the irradiation light, and there is no interaction at the interface between the underlying resist and the TURL itself.
The present invention provides a top anti-reflective coating having high etch resistance. TAR also significantly reduces CD variations in the irradiated photoresist layer.

The present invention particularly provides a TURL comprising an indanone or glutarimide copolymer, a solvent, and an added sensitizer having an orthodiazonaphthoquinone structure.

The present invention also comprises a step of applying a resist layer to the substrate, a step of applying an upper antireflection layer to the surface of the resist layer, and a step of selectively irradiating the substrate with ultraviolet light. The method of manufacturing a semiconductor device, wherein the antireflection layer includes an indanone or glutarimide copolymer, a solvent, and an additional sensitizer having an orthodiazonaphthoquinone structure is applied. Both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.

[0013]

DETAILED DESCRIPTION OF THE INVENTION The TURL material of the present invention contains an indanone or glutarimide copolymer, a solvent immiscible with the underlying resist, and an additive sensitizer having an orthodiazonaphthoquinone structure. The mixture of sensitizers having a naphthyl and cyclohexyl structure has both a refractive index suitable for the wavelength of exposure light such as 193 and 248 nm, and excellent etching resistance.

[0014] Copolymers are made by combining indanone or glutarimide with acrylate or methacrylate, vinyl, olefin, epoxy, or alcohol. Examples of preferred copolymers include the following chemical formulas (1) to (4) and the following general formulas (5) to
This is shown in (7).

[0015]

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[0016]

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The compounds represented by the chemical formulas (1) to (4) are copolymers of methyl methacrylate, vinyl, olefin, epoxy and indanone, respectively. The compounds represented by the above general formulas (5) to (7)
Each is a copolymer of vinyl, olefin, and epoxy with glutarimide. In the chemical formulas (1) to (4) and the general formulas (5) to (7), n represents the number of polymerizations. In the general formulas (5) to (7), the substituent X is H or CH ₃ . And the substituent M is H, CH
₃ or C ₂ H ₅ .

[0018] The amount of the copolymer is sufficient to provide the appropriate TAR on the photoresist and is within the ordinary range of the art. The solvent can be any solvent suitable for preparing the TURL, such as water, methanol,
Includes but is not limited to ethanol or other aqueous solutions that do not mix with the photoresist layer.

The amount of solvent is added in an amount sufficient to dissolve the polymer and is within the normal range in the art. Additive sensitizers are added to the mixture of polymer and solvent to provide a suitable refractive index and etch resistance. Suitable addition sensitizers include those having an orthodiazonaphthoquinone structure selected from the structures represented by the following general formulas (1) to (4).

[0020]

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In the above general formulas (1) to (4), R,
R ¹ and R ² represent hydrogen, a methyl group, or an ethyl group. Other additives may be added to the TURL by methods known to those skilled in the art, as long as the desired properties of the TURL are maintained. For example, a small amount of a surfactant such as a fluorinated ester may be added. An effective amount as a surfactant is contemplated.

The present invention may be used in combination with known substrates having various film layers. The resist may be applied to the substrate or to any desired layer between the substrate and the TURL layer.

In order to simplify the description of the present invention, a process for manufacturing a simple semiconductor device will be described. It should be understood that other processes and combinations of layers are within the scope of the present invention. For example, a semiconductor device is fabricated with a first photoresist-TARL combination,
After forming the desired oxide pattern and removing the photoresist and TAR pieces, a second oxide film is formed, a second TURL-photoresist-TARL combination is formed, and a second oxide film is formed. A desired pattern is formed on the film.

[0024] The substrate can be any conventional substrate suitable for photolithography. Examples of suitable substrates include silicon, polysilicon, germanium, nitride,
And metal.

The photoresist may be a conventional DUV (Deep Ultra Violet) or VUV (Vacuum Ultra Violet) positive or negative underlying resist. A suitable photoresist is AUV, a DUV photoresist commercially available from Shipley.
PEX-E. Suitable VUV photoresists include polymethyl methacrylate (PMMA) and polymethyl isopropenyl ketone (PMIPK).

The photoresist is then baked to achieve evaporation of the photoresist solvent to promote adhesion. The TAR is formed over the photoresist layer. The TAR of the present invention is formed by combining an indanone or glutarimide copolymer, a solvent, and an added sensitizer having an orthodiazonaphthoquinone structure. Any method of combining the copolymer, solvent, and added sensitizer to provide a composition suitable for coating a substrate is contemplated by the inventors.

The TURL material is preferably n ₁ = a-
It has a refractive index of bi, where a is the real part using ac ^1/2 and b is the imaginary part using b ≒ d / 2. TURL
Is preferably t = λ / 4a.

N ₁ : T of the present invention where n ₁ = a-bi
Is the refractive index of the ARL, where a is the number of the real part,
b is the number of the imaginary part. (A is about 1.4 to 1.5 and b is about 0.01 to 0.02.) N ₂ : Refraction of the underlying resist for DUV and VUV lithography where n ₂ = c-di Where c is the number of the real part and d is the number of the imaginary part. (C is about 1.7 to 1.8 and d is about 0.02 to 0.0
3. ) I: Imaginary number λ: Wavelength of exposure light For example only, DUV (λ = 248 nm) resist APEX-E has n ₂ = 1.757-0.009i
have. In this case, the TURL has an a value of about 1.3 to 1.4, a b value of about 0.005, and a t value of about 50 nm.

The TURL of the present invention can be prepared in any suitable manner. For example, it may be prepared by dissolving the copolymer in a solvent and then adding an added sensitizer. Other dispersion methods, such as a gas evaporation method, may be used.

[0030] The preferred conventional method for forming the TAR is spin casting, but known coating methods for coating the desired surface with a layer are also contemplated for producing the TAR.

[0031] Any suitable thickness that provides the desired TAR coating can be used and is well within the ordinary skill in the art. The thickness of the TURL is preferably
It is less than about 100 nm, more preferably less than about 50 nm. The etch bias during a TURL etch is minimized by minimizing the thickness of the TURL.

Methods for coating, baking, exposing, and developing a photoresist layer are known to those skilled in the art and are within the ordinary skill in the art. The TURL is then etched by any method known to those skilled in the art. The photoresist and TAR may be etched together or separately. A typical, but non-limiting example of a suitable etching material is a combination of CF ₄ , Ar, and O ₂ if the underlying substrate is an oxide.

Photoresist and TAR remaining on substrate
The L-strip is then processed by conventional techniques known to those skilled in the art, for example, by plasma ashing or H ₂ SO
₄ and removed by a wet process using H ₂ O ₂ . The photoresist and the TAR strip are removed together or separately, as needed.

The TURL material provides not only a sufficient suppression of thin film interference effects, but also a significant improvement in etch resistance (RIE), even with very thin resists and non-aryl resin type resists.

[0035]

The present invention is further described by reference to the following examples. These examples should not be construed as limiting the invention in any way.

The following is a non-limiting example of fabricating a TURL on a semiconductor device according to the present invention. Other means of providing a TAR on a semiconductor device are within the ordinary scope of the art.

Example 1 Formation of Positive Resist (1) Optionally, BARL is coated on a substrate and baked. (2) A positive resist is coated on BARL or a substrate and baked.

(3) A TAR material is coated on a resist and baked (post-apply bake-
"PAB"). (4) Optionally, immerse the coated substrate in an aqueous solution of tetramethylammonium hydride (TMAH).

(5) 248 nm (KrF) or 193
The substrate is exposed to light of nm (ArF). (6) Develop the TURL using the TMAH aqueous solution.

(7) Optionally, flood exposure using UV (g- or i-line) irradiation light. (8) Perform post-exposure bake (hereinafter referred to as PEB).

(9) The resist is developed using a TMAH aqueous solution. Example 2 Formation of Negative Resist (1) Optionally, BARL is coated on a substrate and baked.

(2) The negative type lower resist is replaced with BARL
Alternatively, it is coated on a substrate and baked. (3) A TRL material is coated on the resist and baked.

(4) Optionally, coat the coated substrate with TM
Immerse in AH aqueous solution. (5) 248 nm (KrF) or 193 nm (Ar
F) Expose the substrate with light.

(6) Perform PEB. (7) Flood exposure using UV irradiation light. (8) The resist is developed using a TMAH aqueous solution.

In general, it is well known that immersing TMAH on a surface containing an orthodiazonaphthoquinone structure induces an "azo-coupling" reaction. Therefore, the thin surface becomes insoluble (or difficult to become soluble). On the other hand, a TAR layer containing an orthodiazonaphthoquinone structure becomes completely insoluble by irradiation with UV light and subsequent PEB. This process is referred to as "image reversal", which requires a baking treatment at 110 ° C. to over 120 ° C. (PEB in this case).

It will be apparent that various modifications and variations can be made in the compositions and methods of the present invention without departing from the spirit or scope of the invention. Therefore,
The present invention is intended to cover modifications and variations of this invention, which are within the scope of the claimed invention and equivalents thereof.

[0047]

As described above, according to the present invention,
An antireflection layer for manufacturing a semiconductor device having a refractive index suitable for the wavelength of exposure light and having no interaction at the interface with a resist is provided. Further, according to the present invention, there is provided an antireflection layer for manufacturing a semiconductor device having high etching resistance.

Further, according to the present invention, there are provided an anti-reflection layer for manufacturing a semiconductor device and a method for manufacturing a semiconductor device, which significantly reduce the fluctuation of CD in the irradiated photoresist layer.

Claims (9)

[Claims] 1. A semiconductor device for reducing the reflection of exposure light in the manufacture of a semiconductor device, comprising a copolymer of indanone or glutarimide, a solvent, and an additive sensitizer having an orthodiazonaphthoquinone structure. Anti-reflection layer for manufacturing. 2. The anti-reflection layer according to claim 1, wherein the solvent is selected from the group consisting of water, methanol, ethanol, and another aqueous solution immiscible with the photoresist layer. 3. The method according to claim 1, wherein the sensitizer is of the following general formula (1):
The antireflection layer for manufacturing a semiconductor device according to claim 1, wherein the antireflection layer is selected from the compounds described in (4). Embedded image (In the formula, R, R ¹ , and R ² represent hydrogen, a methyl group, or an ethyl group.) 4. The method of claim 1, wherein the copolymer is made by combining indanone or glutarimide with an acrylate, methacrylate, vinyl, olefin, epoxy, or alcohol.
4. The anti-reflection layer for manufacturing a semiconductor device according to any one of items 3 to 3. 5. The method according to claim 1, further comprising: applying a photoresist on the surface of the substrate, forming an anti-reflection layer on the surface of the photoresist, and selectively irradiating the substrate with ultraviolet light. A method for manufacturing a semiconductor device, wherein the layer contains an indanone or glutarimide copolymer, a solvent, and an additive sensitizer having an orthodiazonaphthoquinone structure. 6. The method according to claim 5, wherein the solvent is selected from the group consisting of water, methanol, ethanol, and another aqueous solution immiscible with the photoresist layer. 7. The method according to claim 1, wherein the sensitizer is of the following general formula (1):
7. The method for manufacturing a semiconductor device according to claim 5, wherein the method is selected from the compounds described in (4). Embedded image (In the formula, R, R ¹ , and R ² represent hydrogen, a methyl group, or an ethyl group.) 8. The copolymer of claim 5, wherein the copolymer is made by combining indanone or glutarimide with an acrylate, methacrylate, vinyl, olefin, epoxy, or alcohol.
8. The method of manufacturing a semiconductor device according to any one of items 7 to 7. 9. A method for manufacturing a semiconductor device using a lithography technique, wherein a step of applying a photoresist layer on a surface of a substrate, a step of forming an antireflection layer on the surface of the photoresist layer, and Wherein the antireflection film contains a copolymer of indanone or glutarimide, a solvent, and an additive sensitizer having an orthodiazonaphthoquinone structure. .