KR20230083595A - Method of forming patterns - Google Patents

Abstract

The present invention relates to a pattern forming method, which comprises: a step of applying a metal-containing resist composition on a substrate; a step of removing edge beads by applying an edge bead removal composition along the edge of the substrate for cleaning; a step for heat treatment to form a metal-containing resist film on the substrate by drying and heating; and a step of forming a resist pattern by exposure and heating, wherein the composition for removing the edge beads includes a compound represented by a chemical formula 1 and an organic solvent. The description of the chemical formula 1 is as described in the specification. A pattern forming method according to one embodiment reduces metal-based contamination inherent in a metal-containing resist, thereby reducing metal-based contamination at the edges and edges of the substrate. By eliminating the resist applied to the back side, the needs of processing and patterning smaller features can be met.

Description

Pattern forming method {METHOD OF FORMING PATTERNS}

The present disclosure relates to a pattern forming method comprising an edge bead removal step.

In recent years, the semiconductor industry has been accompanied by a continual reduction in critical dimensions, which requires new types of high-performance photoresist materials and patterning methods to meet the demands of processing and patterning of increasingly smaller features. there is.

In addition, with the recent rapid development of the semiconductor industry, operating speed and large-capacity storage capacity of semiconductor devices are required, and process technologies for improving integration, reliability, and response speed of semiconductor devices are being developed in line with these demands. In particular, it is important to accurately control/inject impurities into the working regions of the silicon substrate, and to interconnect these regions to form devices and ultra-high-density integrated circuits, which is possible through a photolithography process. That is, it has become important to consider the integration of a photolithography process that includes applying a photoresist on a substrate, selectively exposing it by irradiating ultraviolet rays (including extreme ultraviolet rays), electron beams, or X-rays, and then developing.

In particular, in the process of forming a photoresist layer, resist is applied on the substrate while rotating the silicon substrate. or cause pattern defects. Therefore, a process of stripping and removing the photoresist applied to the edge and back surface of the silicon substrate using a thinner composition, that is, an EBR (EDGE BEAD REMOVAL) process is performed. The EBR process requires a composition that exhibits excellent solubility in photoresist and does not generate resist residue by effectively removing beads and photoresist remaining on the substrate.

One embodiment provides a pattern formation method, in particular, a pattern formation method including an edge bead removal step.

A pattern forming method according to an embodiment includes applying a metal-containing resist composition on a substrate; removing edge beads by applying and cleaning a composition for removing edge beads along the edge of the substrate; a heat treatment step of drying and heating to form a metal-containing resist film on the substrate; and exposing and developing to form a resist pattern;

The composition for removing edge beads may include a compound represented by Chemical Formula 1 below and an organic solvent.

[Formula 1]

In Formula 1,

R ¹ to R ³ are each independently a substituted or unsubstituted C1 to C20 alkyl group;

X is F, Cl, Br or I;

n is an integer from 1 to 5;

The composition for removing edge beads may include 0.1 to 50% by weight of the additive and 50 to 99.9% by weight of the organic solvent.

After the exposure and development processes, a step of cleaning by applying a composition for removing edge beads may be further included.

The n may be one of integers from 1 to 3.

The X may be F.

Wherein R ¹ to R ³ are each independently a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted n-propyl group, a substituted or unsubstituted n-butyl group, a substituted or unsubstituted iso - It may be selected from a propyl group, a substituted or unsubstituted sec-butyl group, and a substituted or unsubstituted iso-butyl group.

The moisture content of the composition for removing edge beads may be 1,000 ppm or less.

The metal compound included in the metal-containing resist may include at least one of an alkyl tin oxo group and an alkyl tin carboxyl group.

The metal compound may be represented by Formula 2 below.

[Formula 2]

In Formula 2,

R ⁴ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, or a substituted or unsubstituted C2 to C20 alkynyl group a C6 to C30 aryl group, a substituted or unsubstituted C6 or C30 arylalkyl group, and -R ^a -OR ^b (where R ^a is a substituted or unsubstituted C1 to C20 alkylene group, and R ^b is a substituted or unsubstituted It is selected from C1 to C20 alkyl groups),

R ⁵ to R ⁷ are each independently selected from -OR ^c or -OC(=O)R ^d ;

R ^c is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, substituted or unsubstituted A C6 to C30 aryl group, or a combination thereof,

R ^d is hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group, An unsubstituted C6 to C30 aryl group, or a combination thereof.

The pattern formation method according to an embodiment can reduce metal-based contamination inherent in metal-containing resists to meet the needs of processing and patterning of smaller features by removing the resist applied to the edge and back surface of the substrate. .

1 is a schematic diagram showing a photoresist coating device.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, in describing the present description, descriptions of already known functions or configurations will be omitted to clarify the gist of the present description.

In order to clearly describe the description, parts irrelevant to the description have been omitted, and the same reference numerals are used for the same or similar components throughout the specification. In addition, since the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, the present description is not necessarily limited to those shown.

In the drawings, the thickness is shown enlarged to clearly express the various layers and regions. Also, in the drawings, the thicknesses of some layers and regions are exaggerated for convenience of description. When a part such as a layer, film, region, plate, etc. is said to be "on" or "on" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between.

1 is a schematic diagram showing a photoresist coating device.

Referring to FIG. 1 , a substrate support 1 on which a substrate W is placed is provided, and the substrate support 1 includes a spin chuck or a spin coater.

The substrate support 1 rotates in a first direction at a predetermined rotational speed and provides centrifugal force to the substrate W. A spray nozzle 2 is positioned on the substrate support 1, and the spray nozzle 2 is located in a waiting area away from the top of the substrate W, and moves to the top of the substrate in the step of supplying the photoresist solution 10. ) can be injected. Accordingly, the photoresist solution 10 is applied to the surface of the substrate by the centrifugal force. At this time, the photoresist solution 10 supplied to the center of the substrate (W) is applied while spreading to the edge of the substrate (W) by centrifugal force, and a part of it is moved to the side surface of the substrate and the lower edge of the substrate. do.

That is, in the coating process, the photoresist solution 10 is mainly applied by a spin coating method. A predetermined amount of the viscous photoresist solution 10 is supplied to the central portion of the substrate W and gradually spread toward the edge of the substrate by centrifugal force. I'm going.

Accordingly, the thickness of the photoresist is formed evenly by the rotational speed of the substrate support.

However, as the solvent evaporates, the viscosity gradually increases, and a relatively large amount of photoresist is accumulated on the edge of the substrate due to the action of surface tension. edge bead) (12).

Hereinafter, a pattern forming method according to an embodiment will be described.

A pattern forming method according to an embodiment includes applying a metal-containing resist composition on a substrate, removing edge beads by applying and cleaning an edge bead removal composition along an edge of the substrate, drying and heating the substrate A heat treatment step of forming a metal-containing resist film thereon, and a step of exposing and developing to form a resist pattern.

More specifically, the step of forming a pattern using a metal-containing resist composition includes a process of applying the metal-containing resist composition on a substrate on which a thin film is formed by spin coating, slit coating, inkjet printing, or the like, and the applied metal-containing resist composition. A process of forming a photoresist film by drying may be included. The metal-containing resist composition may include a tin-based compound, and for example, the tin-based compound may include at least one of an alkyl tin oxo group and an alkyl tin carboxyl group.

For example, the metal compound included in the metal-containing resist may be represented by Chemical Formula 2 below.

[Formula 2]

In Formula 2,

R ⁴ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, or a substituted or unsubstituted C2 to C20 alkynyl group a C6 to C30 aryl group, a substituted or unsubstituted C6 or C30 arylalkyl group, and -R ^a -OR ^b (where R ^a is a substituted or unsubstituted C1 to C20 alkylene group, and R ^b is a substituted or unsubstituted It is selected from C1 to C20 alkyl groups),

R ⁵ to R ⁷ are each independently selected from -OR ^c or -OC(=O)R ^d ;

R ^c is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, substituted or unsubstituted A C6 to C30 aryl group, or a combination thereof,

R ^d is hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group, An unsubstituted C6 to C30 aryl group, or a combination thereof.

In one embodiment, the composition for removing edge beads may include a compound represented by Chemical Formula 1 below and an organic solvent.

[Formula 1]

In Formula 1,

R ¹ to R ³ are each independently a substituted or unsubstituted C1 to C20 alkyl group;

X is F, Cl, Br or I;

n is an integer from 1 to 5;

The compound represented by Chemical Formula 1 is an adduct and is different from an ionic compound, and an adduct may have a higher solubility than an ionic compound. Accordingly, edge bead removal can be performed more efficiently.

The composition for removing edge beads may include 0.1 to 50% by weight of the additive and 50 to 99.9% by weight of the organic solvent.

In a specific embodiment, the composition for removing the edge bead may include 0.5 to 40% by weight, specifically 0.5 to 30% by weight, and more specifically 1 to 20% by weight of the additive.

As an example of the organic solvent included in the composition for removing edge beads of a metal-containing resist according to an embodiment, propylene glycol methyl ether (PGME), propylene glycol methyl ether acetate (PGMEA), propylene glycol butyl ether (PGBE), ethylene glycol Methyl ether, diethyl glycol ethyl methyl ether, dipropyl glycol dimethyl ether, ethanol, 2-butoxyethanol, n-propanol, isopropanol, n-butanol, isobutyl alcohol, hexanol, ethylene glycol, propylene glycol, heptanone, Propylene carbonate, butylene carbonate, diethyl ether, diisopropyl ether, dibutyl ether, ethyl acetate, ethyl lactate, methyl-2-hydroxy-isobutyrate, gamma-butyrolactone, methyl 3-methoxypropio nate, ethyl 3-ethoxypropionate, methyl isobutyl carbinol (MIBC), n-butyl acetate, diisopentyl ether, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dimethyl sulfoxide side, dimethylformamide, acetonitrile, acetylacetone, diacetone alcohol, 3,3-dimethyl-2-butanone, N-methyl-2-pyrrolidone, dimethylacetamide, cyclohexanone or mixtures thereof, etc. Examples include, but are not limited to.

The composition for edge bead removal of metal-containing resists according to the present invention may be particularly effective for removing metal-containing resists, more particularly undesirable metal residues, such as tin-based metal residues.

For example, n may be one of integers from 1 to 3.

For example, the X may be F.

For example, the R ¹ to R ³ may each independently be a substituted or unsubstituted C1 to C10 alkyl group, specifically a substituted or unsubstituted C1 to C5 alkyl group, such as a substituted or unsubstituted methyl group, a substituted Or an unsubstituted ethyl group, a substituted or unsubstituted n-propyl group, a substituted or unsubstituted n-butyl group, a substituted or unsubstituted iso-propyl group, a substituted or unsubstituted sec-butyl group, and a substituted or unsubstituted It may be selected from cyclic iso-butyl groups.

In one embodiment, the compound represented by Chemical Formula 1 may be at least one of triethylamine trihydrofluoride, diethylamine hydrochloride, and triethylamine hydrochloride.

The composition for removing edge beads may have a moisture content of 1,000 ppm or less.

When the water content in the composition exceeds 1,000 ppm, film quality deformation may occur due to hydration in the photoresist contact area.

Specifically, the composition for removing the edge bead of the metal-containing resist is applied in an appropriate amount along the edge of the substrate, and after the composition for removing the edge bead of the metal-containing resist is transferred, at an appropriate speed (eg, 1,000 rpm or more) Spinning the substrate may include removing the beads on the edge of the substrate.

Subsequently, a first heat treatment process of heating the substrate on which the photoresist film is formed is performed. The first heat treatment process may be performed at a temperature of about 80° C. to about 120° C. In this process, the solvent is evaporated and the photoresist film may be more firmly adhered to the substrate.

Then, the photoresist film is selectively exposed to light.

For example, examples of the light usable in the exposure process include light having a short wavelength such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), and ArF excimer laser (wavelength 193 nm) as well as EUV (wavelength 193 nm). Extreme UltraViolet (wavelength 13.5 nm), light having a high energy wavelength such as E-Beam (electron beam), etc. may be mentioned.

More specifically, light for exposure according to an embodiment may be short-wavelength light having a wavelength range of 5 nm to 150 nm, and light having a high-energy wavelength such as EUV (Extreme Ultraviolet; wavelength 13.5 nm) or E-Beam (electron beam). can

In the forming of the photoresist pattern, a negative pattern may be formed.

The exposed region of the photoresist film has a different solubility from the unexposed region of the photoresist film as a polymer is formed by a crosslinking reaction such as condensation between organometallic compounds.

Subsequently, a second heat treatment process is performed on the substrate. The second heat treatment process may be performed at a temperature of about 90 °C to about 200 °C. As a result of performing the second heat treatment process, the exposed region of the photoresist film becomes difficult to dissolve in a developing solution.

Specifically, the photoresist pattern corresponding to the negative tone image may be completed by dissolving the photoresist film corresponding to the unexposed area using an organic solvent such as 2-heptanone and then removing the film. .

The developer used in the pattern formation method according to one embodiment may be an organic solvent, for example, ketones such as methyl ethyl ketone, acetone, cyclohexanone, 2-heptanone, 4-methyl-2-propanol, 1 Alcohols such as butanol, isopropanol, 1-propanol and methanol, esters such as propylene glycol methyl ether acetate, ethyl acetate, ethyl lactate, n-butyl acetate and butyrolactone, aromatics such as benzene, xylene and toluene compounds, or combinations thereof.

In addition, the pattern forming method may further include cleaning by applying a composition for removing edge beads of a metal-containing resist after the exposure and development processes.

As described above, as well as light having wavelengths such as i-line (wavelength 365 nm), KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), The photoresist pattern formed by exposure to light having high energy such as an E-Beam (electron beam) may have a width of 5 nm to 100 nm. For example, the photoresist pattern is 5 nm to 90 nm, 5 nm to 80 nm, 5 nm to 70 nm, 5 nm to 60 nm, 5 nm to 50 nm, 5 nm to 40 nm, 5 nm to 30 nm , may be formed with a width of 5 nm to 20 nm thickness.

On the other hand, the photoresist pattern has a half-pitch of about 50 nm or less, for example 40 nm or less, for example 30 nm or less, for example 20 nm or less, for example 15 nm or less, and about It may have a pitch having a line width roughness of 10 nm or less, about 5 nm or less, about 3 nm or less, or about 2 nm or less.

Hereinafter, the present invention will be described in more detail through examples related to the preparation of the above-described composition for removing edge beads of a metal-containing resist. However, the technical features of the present invention are not limited by the following examples.

Example: Preparation of composition for edge bead removal of metal-containing resist

Examples 1 to 5 and Comparative Examples 1 to 6

After putting the components according to the composition of Table 1 in the PP bottle, mixing, shaking at room temperature (25 ℃) to dissolve completely. Then, a composition for removing edge beads was prepared by passing through a filter made of PTFE having a pore size of 1 μm.

Preparation Example: Preparation of organometallic photoresist composition

After dissolving an organometallic compound having the structure of Chemical Formula C at a concentration of 1 wt% in 4-methyl-2-pentanol, the photoresist composition was filtered through a 0.1 μm PTFE syringe filter. manufactured.

[Formula C]

Evaluation 1: Residual film thickness evaluation (Strip test) and Sn residual amount evaluation

On a 6-inch silicon wafer, 10 mL of the photoresist composition containing an organometallic compound according to the above Preparation Example was added, left for 20 seconds, and then spin-coated at a speed of 800 rpm for 30 seconds. 10 mL of each of the compositions for removing edge beads prepared in Examples 1 to 5 and Comparative Examples 1 to 6 was added to the wafer on which the coating film was formed, and after standing for 20 seconds, spin drying at a speed of 1,500 rpm for 30 seconds do. Subsequently, the thickness of the film obtained by heat treatment at 150 ° C for 60 seconds was re-measured by ellipsometry to confirm the thickness change before and after the edge bead removal process, and evaluated according to the following criteria. ^st residual amount) was confirmed, and the results are shown in Table 1.

* In the case of residual thickness less than 2Å: ○, in the case of more than 2Å: X

Evaluation 2: Visual evaluation of stain on the back side

As in Evaluation 1, the surface stains of the wafer on which the resist film was formed through the edge bead removal process were confirmed using the KMAC-ST400DLX equipment, and at the same time, the stains on the back side of the substrate were stained before/after the second heat treatment at 150 ° C for 60 seconds. visually check the The notation standards are as follows.

* No stains before/after 2nd heat treatment: ○, stains after 2nd heat treatment: X

Composition for edge bead removal After Strip
residual film back side stain
(visual evaluation) before development
Sn residual amount
(1 ^st remaining)
(x10 ¹⁰ atoms/cm ² ) compound weight% menstruum
(weight%) Example
One triethylamine
trihydrofluoride 10 PGMEA(90) ○ ○ 6.3 Example
2 5 PGMEA(95) ○ ○ 13 Example 3 One PGMEA(99) ○ ○ 21 Example 4 0.5 PGMEA(95.5) ○ ○ 29 Example 5 0.1 PGMEA(99.9) ○ ○ 130 comparative example
One acetic acid 40 PGMEA(60) ○ ○ 400 Comparative Example 2 Ethylenediamine 10 PGMEA(90) ○ ○ 6300 Comparative Example 3 triethanolamine 10 PGMEA(90) ○ X 1200 Comparative Example 4 Benzene-1,2-diamine 10 PGMEA(90) ○ X 3500 comparative example
5 trimethylammonium fluoride 0.1 PGMEA(99.9) ○ ○ 5600 comparative example
6 diethanolamine 10 MIBC(90) ○ ○ 1100 comparative example
6 tris(2-aminoethyl)amine 10 MIBC(90) X X 5700

Referring to Table 1, the compositions for removing edge beads of metal-containing resists according to Examples 1 to 5 have excellent metal removal effects compared to the compositions for removing edge beads of metal-containing resists according to Comparative Examples 1 to 6, It can be seen that the reduction of metal can be further promoted.

In the foregoing, although specific embodiments of the present invention have been described and shown, the present invention is not limited to the described embodiments, and it is common knowledge in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. It is self-evident to those who have Therefore, such modifications or variations should not be individually understood from the technical spirit or viewpoint of the present invention, and modified embodiments should fall within the scope of the claims of the present invention.

1: substrate support 2: spray nozzle
10: photoresist solution 12: edge bead

Claims (9)

applying a metal-containing resist composition on a substrate;
removing edge beads by applying and cleaning a composition for removing edge beads along the edge of the substrate;
a heat treatment step of drying and heating to form a metal-containing resist film on the substrate; and
Forming a resist pattern by exposure and development
including,
The pattern forming method, wherein the composition for removing edge beads includes a compound represented by Formula 1 below and an organic solvent:
[Formula 1]

In Formula 1,
R ¹ to R ³ are each independently a substituted or unsubstituted C1 to C20 alkyl group;
X is F, Cl, Br or I;
n is an integer from 1 to 5; In paragraph 1,
The composition for removing edge beads includes 0.1 to 50% by weight of the compound represented by Formula 1 and 50 to 99.9% by weight of the organic solvent. In paragraph 1,
After the exposure and development processes, the pattern forming method further comprising the step of cleaning by applying a composition for removing edge beads. In paragraph 1,
Wherein n is one of integers from 1 to 3, pattern forming method. In paragraph 1,
Wherein X is F, the pattern forming method. In paragraph 1,
Wherein R ¹ to R ³ are each independently a substituted or unsubstituted methyl group, a substituted or unsubstituted ethyl group, a substituted or unsubstituted n-propyl group, a substituted or unsubstituted n-butyl group, a substituted or unsubstituted iso - A method for forming a pattern, which is one selected from a propyl group, a substituted or unsubstituted sec-butyl group, and a substituted or unsubstituted iso-butyl group. In paragraph 1,
The water content of the edge bead removal composition is 1,000 ppm or less, pattern forming method. In paragraph 1,
wherein the metal-containing resist composition comprises a metal compound comprising at least one of an alkyl tin oxo group and an alkyl tin carboxyl group. In paragraph 8,
The metal compound is represented by Formula 2, a pattern forming method:
[Formula 2]

In Formula 2,
R ⁴ is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, or a substituted or unsubstituted C2 to C20 alkynyl group a C6 to C30 aryl group, a substituted or unsubstituted C6 or C30 arylalkyl group, and -R ^a -OR ^b (where R ^a is a substituted or unsubstituted C1 to C20 alkylene group, and R ^b is a substituted or unsubstituted It is selected from C1 to C20 alkyl groups),
R ⁵ to R ⁷ are each independently selected from -OR ^c or -OC(=O)R ^d ;
R ^c is a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group A C6 to C30 aryl group, or a combination thereof,
R ^d is hydrogen, a substituted or unsubstituted C1 to C20 alkyl group, a substituted or unsubstituted C3 to C20 cycloalkyl group, a substituted or unsubstituted C2 to C20 alkenyl group, a substituted or unsubstituted C2 to C20 alkynyl group, a substituted or unsubstituted C2 to C20 alkynyl group, An unsubstituted C6 to C30 aryl group, or a combination thereof.

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