JP2010129932A - Surface treatment method and liquid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface treatment method by which pattern tumbles of a resin pattern and an etching pattern can be prevented effectively, and to provide a surface treatment liquid for use in the surface treatment method. <P>SOLUTION: The surface treatment method includes a process for treating the surface of a resin pattern formed on a substrate or an etched pattern formed on the substrate by etching with a surface treatment liquid containing a silylation agent and a solvent, and a process for cleaning the resin pattern obtained after treatment by the surface treatment liquid, or the etched pattern. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface treatment method effective for preventing pattern collapse during the formation of a high aspect ratio fine pattern, and a surface treatment liquid used in the surface treatment method.

  In the manufacture of semiconductor devices and the like, a lithography technique is used when processing such as etching is performed on a substrate. In this lithography technique, a photosensitive resin layer is provided on a substrate using a photosensitive resin composition, and then this is selectively irradiated with actinic radiation for exposure and development, and then the photosensitive resin layer is formed. By selectively dissolving and removing, a resin pattern is formed on the substrate. Then, an etching target pattern is formed on the substrate by performing an etching process using this resin pattern as a mask.

By the way, in recent years, the trend toward higher integration and miniaturization of semiconductor devices has increased, and the miniaturization and high aspect ratio of the resin pattern serving as a mask have also been advanced. However, on the other hand, the problem of so-called pattern collapse has arisen. This pattern collapse is such that when a large number of resin patterns are formed in parallel on a substrate, adjacent resin patterns are close to each other so that the resin pattern may break or peel off from the base in some cases. It is a phenomenon. When such a pattern collapse occurs, a desired product cannot be obtained, which causes a decrease in product yield and reliability.
Recently, not only a resin pattern but also a pattern to be etched has a problem of pattern collapse.

  It is known that this pattern collapse occurs due to the surface tension of the cleaning liquid when the cleaning liquid dries in the cleaning process after pattern formation. That is, when the cleaning liquid is removed in the drying process, a stress based on the surface tension of the cleaning liquid acts between the patterns, and the pattern collapses.

Thus, many attempts have been made to prevent pattern collapse by adding a substance that lowers the surface tension to the cleaning liquid. For example, a cleaning solution to which isopropyl alcohol has been added, a cleaning solution to which a fluorosurfactant has been added, and the like have been proposed (Patent Documents 1 and 2).
JP-A-6-163391 JP-A-7-142349

  However, there has been a problem that such a devising cleaning solution is insufficient to prevent pattern collapse.

  The present invention has been made in view of such a conventional situation, and is used in a surface treatment method capable of effectively preventing pattern collapse of a resin pattern or a pattern to be etched, and the surface treatment method. An object is to provide a surface treatment liquid.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, the surface of the resin pattern or the pattern to be etched is hydrophobized by treatment with a surface treatment liquid containing a silylating agent and a solvent, and the above problem can be solved by increasing the contact angle of the cleaning liquid. It came to be completed. Specifically, the present invention provides the following.

  The first aspect of the present invention is a process of treating a resin pattern provided on a substrate or a surface of an etching pattern formed on a substrate by etching with a surface treatment liquid containing a silylating agent and a solvent; Cleaning the resin pattern or the pattern to be etched after the treatment with the surface treatment liquid.

  A second aspect of the present invention is a surface treatment liquid that contains a silylating agent and a solvent and is used in the surface treatment method according to the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the surface treatment liquid which can prevent the pattern collapse of a resin pattern or a to-be-etched pattern effectively, and the surface treatment liquid used with the surface treatment method can be provided.

≪Surface treatment method≫
First, the surface treatment method according to the present invention will be described.
The surface treatment method according to the present invention treats the surface of a pattern to be etched formed on a substrate by etching or a resin pattern provided on the substrate with the surface treatment liquid according to the present invention containing a silylating agent and a solvent. And a step of cleaning the resin pattern or the pattern to be etched after the treatment with the surface treatment liquid.

Although it does not specifically limit as a resin pattern, The resin pattern etc. which were formed by apply | coating a conventionally well-known photosensitive resin composition on a board | substrate, and exposing and developing are mentioned. The photosensitive resin composition may be positive or negative, and may be chemically amplified or non-chemically amplified.
The pattern to be etched is not particularly limited, but includes a pattern formed by etching the substrate using the above resin pattern as a mask. Examples of the material of the pattern to be etched include silicon, silicon nitride, titanium nitride, and tungsten.

Usually, after the resin pattern as described above is formed, the development residue and the attached developer are generally removed by washing with a cleaning solution such as water or an activator rinse. Further, even after the pattern to be etched as described above is formed, the pattern surface is generally cleaned with a cleaning solution such as SPM (sulfuric acid / hydrogen peroxide solution) or APM (ammonia / hydrogen peroxide solution). .
On the other hand, in the surface treatment method according to the present invention, before cleaning such a resin pattern or a pattern to be etched, the pattern surface is treated with the surface treatment liquid according to the present invention (described later), and the pattern surface is made hydrophobic. Turn into.

Here, a force F acting between patterns such as a resin pattern and a pattern to be etched at the time of cleaning is expressed as the following formula (I). Where γ represents the surface tension of the cleaning liquid, θ represents the contact angle of the cleaning liquid, A represents the aspect ratio of the pattern, and D represents the distance between the pattern sidewalls.
F = 2γ · cos θ · A / D (I)

  Therefore, if the pattern surface can be hydrophobized and the contact angle of the cleaning liquid can be increased, the force acting between the patterns during subsequent cleaning can be reduced, and pattern collapse can be prevented.

  This surface treatment is performed by immersing the substrate on which the resin pattern or the etching target pattern is formed in the surface processing liquid, or by applying or spraying the surface processing liquid onto the resin pattern or the etching target pattern. The treatment time is preferably 1 to 60 seconds. Moreover, after this surface treatment, the contact angle of water on the pattern surface is preferably 40 to 120 degrees, and more preferably 60 to 100 degrees.

  When the above surface treatment is completed, the resin pattern or the pattern to be etched is cleaned. For this cleaning process, it is possible to employ a cleaning solution that has been used for cleaning a resin pattern or a pattern to be etched. For example, water, an activator rinse, etc. are mentioned about a resin pattern, SPM, APM, etc. are mentioned about a to-be-etched pattern.

  From the viewpoint of throughput, it is preferable that the surface treatment and the cleaning treatment are continuous treatments. For this reason, it is preferable to select a surface treatment liquid that is excellent in substituting property with the cleaning liquid.

≪Surface treatment liquid≫
Next, the surface treatment liquid according to the present invention will be described.
The surface treatment liquid according to the present invention contains a silylating agent and a solvent. Hereinafter, each component will be described in detail.

<Silylating agent>
The silylating agent is not particularly limited, and any conventionally known silylating agent can be used. Specifically, for example, silylating agents represented by the following formulas (1) to (3) can be used.

（式（１）中、Ｒ^１は水素原子、又は飽和若しくは不飽和アルキル基を示し、Ｒ^２は飽和若しくは不飽和アルキル基、飽和若しくは不飽和シクロアルキル基、又は飽和若しくは不飽和ヘテロシクロアルキル基を示す。Ｒ^１及びＲ^２は互いに結合して窒素原子を有する飽和又は不飽和ヘテロシクロアルキル基を形成してもよい。）

(In formula (1), R ¹ represents a hydrogen atom or a saturated or unsaturated alkyl group, and R ² represents a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, or a saturated or unsaturated heterocycloalkyl group. R ¹ and R ² may combine with each other to form a saturated or unsaturated heterocycloalkyl group having a nitrogen atom.

（式（２）中、Ｒ^３は水素原子、メチル基、トリメチルシリル基、又はジメチルシリル基を示し、Ｒ^４，Ｒ^５はそれぞれ独立に水素原子、メチル基、アルキル基、又はビニル基を示す。）

(In Formula (2), R ³ represents a hydrogen atom, a methyl group, a trimethylsilyl group, or a dimethylsilyl group, and R ⁴ and R ⁵ each independently represent a hydrogen atom, a methyl group, an alkyl group, or a vinyl group. )

（式（３）中、ＸはＯ、ＣＨＲ^７、ＣＨＯＲ^７、ＣＲ^７Ｒ^７、又はＮＲ^８を示し、Ｒ^６，Ｒ^７はそれぞれ独立に水素原子、飽和若しくは不飽和アルキル基、飽和若しくは不飽和シクロアルキル基、トリアルキルシリル基、トリアルキルシロキシ基、アルコキシ基、フェニル基、フェネチル基、又はアセチル基を示し、Ｒ^８は水素原子、アルキル基、又はトリアルキルシリル基を示す。）

(In the formula (3), X represents O, CHR ⁷ , CHOR ⁷ , CR ⁷ R ⁷ , or NR ⁸ , and R ⁶ and R ⁷ are each independently a hydrogen atom, a saturated or unsaturated alkyl group, saturated or unsaturated. A saturated cycloalkyl group, a trialkylsilyl group, a trialkylsiloxy group, an alkoxy group, a phenyl group, a phenethyl group, or an acetyl group, and R ⁸ represents a hydrogen atom, an alkyl group, or a trialkylsilyl group.

  Examples of the silylating agent represented by the above formula (1) include N, N-dimethylaminotrimethylsilane, N, N-diethylaminotrimethylsilane, t-butylaminotrimethylsilane, allylaminotrimethylsilane, trimethylsilylacetamide, and trimethylsilyl. Examples include piperidine, trimethylsilylimidazole, trimethylsilylmorpholine, 3-trimethylsilyl-2-oxazolidinone, trimethylsilylpyrazole, trimethylsilylpyrrolidine, 2-trimethylsilyl-1,2,3-triazole, 1-trimethylsilyl-1,2,4-triazole and the like.

  Examples of the silylating agent represented by the above formula (2) include hexamethyldisilazane, N-methylhexamethyldisilazane, 1,2-di-N-octyltetramethyldisilazane, 1,2-divinyltetra. Examples include methyldisilazane, heptamethyldisilazane, nonamethyltrisilazane, and tris (dimethylsilyl) amine.

  Examples of the silylating agent represented by the above formula (3) include trimethylsilyl acetate, trimethylsilylpropionate, trimethylsilylbutyrate, trimethylsilyloxy-3-penten-2-one, and the like.

  Among these, N, N-dimethylaminotrimethylsilane (DMATMS) is preferable because the hydrophobicity can be further increased.

  The content of the silylating agent is preferably 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and further preferably 1.0 to 20% by mass in the surface treatment liquid. By setting it as the said range, after ensuring the applicability | paintability of a surface treatment liquid, the hydrophobicity of a pattern surface can fully be improved.

<Solvent>
As the solvent, any conventionally known solvent can be used as long as it can dissolve the silylating agent and causes little damage to the resin pattern to be surface-treated or the pattern to be etched.
Specifically, sulfoxides such as dimethylsulfoxide; sulfones such as dimethylsulfone, diethylsulfone, bis (2-hydroxyethyl) sulfone, tetramethylenesulfone; N, N-dimethylformamide, N-methylformamide, N, N -Amides such as dimethylacetamide, N-methylacetamide, N, N-diethylacetamide; N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-hydroxymethyl-2 -Lactams such as pyrrolidone and N-hydroxyethyl-2-pyrrolidone; 1,3-dimethyl-2-imidazolidinone, 1,3-diethyl-2-imidazolidinone, 1,3-diisopropyl-2-imidazolidi Non-imidazolidinones such as non-dimethyl ether, diethyl ether Dialkyl ethers such as tellurium, methyl ethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether; dialkyl glycol ethers such as dimethyl glycol, dimethyl diglycol, dimethyl triglycol, methyl ethyl diglycol, diethyl glycol; methyl ethyl ketone, cyclohexanone, Ketones such as 2-heptanone and 3-heptanone; terpenes such as p-menthane, diphenylmenthane, limonene, terpinene, bornane, norbornane and pinane;

  Among these, dialkyl glycol ethers and terpenes are preferable from the viewpoint of surface treatment effect and displaceability with a cleaning solution. These solvents can be used alone or in combination of two or more.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, this invention is not limited to the following Example at all.

[Preparation of surface treatment solution]
As shown in Table 1, N, N-dimethylaminotrimethylsilane (DMATMS) or hexamethyldisilazane (HMDS) was used as a silylating agent, and this was used as diethyldiglycol (DEDG), p-menthane, dimethylsulfoxide (DMSO). ) Or 5% by mass with cyclohexanone (Anone) to prepare surface treatment liquids 1-8.

[Confirmation of hydrophobic effect]
Surface treatment liquids 1 to 8 were applied on an 8-inch silicon wafer, subjected to paddle surface treatment while rotating at 100 rpm for 30 seconds, and subsequently washed with ethyl lactate while rotating at 1000 rpm for 20 seconds. Thereafter, the wafer was rotated at 3000 rpm for 20 seconds to dry the wafer. Then, using Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.), a pure water droplet (1.5 μL) was dropped on the wafer surface, and the contact angle 10 seconds after the dropping was measured. The results are shown in Table 2.
As the surface treatment liquid, in addition to the surface treatment liquid immediately after preparation (after about 6 minutes), a surface treatment liquid having a storage period of 30 minutes, 3 hours, 12 hours, 24 hours, and 1 week at room temperature is used. It was.
As a control, the contact angle of the silicon wafer before the surface treatment was measured in the same manner as described above.

[Confirmation of replaceability]
Apply water while rotating an 8-inch silicon wafer at 1000 rpm for 20 seconds, then apply surface treatment liquids 1 to 8, perform paddle surface treatment while rotating at 100 rpm for 30 seconds, and continue to rotate at 1000 rpm for 20 seconds. Washing with ethyl lactate was performed. Thereafter, the wafer was rotated at 3000 rpm for 20 seconds to dry the wafer. Then, using Dropmaster 700 (manufactured by Kyowa Interface Science Co., Ltd.), a pure water droplet (1.5 μL) was dropped on the wafer surface, and the contact angle 10 seconds after the dropping was measured. The results are shown in Table 3.
In addition, as the surface treatment liquid, the surface treatment liquid immediately after preparation (after about 6 minutes) was used.
Further, the evaluation of the substitutability is as follows: Table 2 shows a contact angle of 75% or more compared to the contact angle when using the surface treatment liquid immediately after preparation (after about 6 minutes), 20% or more A sample having a contact angle of less than 75% was evaluated as Δ, and a sample having a contact angle of less than 20% was evaluated as ×.

As can be seen from Table 2, the hydrophobicity of the silicon wafer could be increased by treatment with a surface treatment solution containing a silylating agent and a solvent. Therefore, when the surface treatment of the pattern to be etched is performed using this surface treatment liquid, the force acting between the patterns is weakened by increasing the contact angle of the cleaning liquid, and pattern collapse is effectively prevented. Conceivable. In particular, the surface treatment liquids 1 and 2 using N, N-dimethylaminotrimethylsilane as a silylating agent and diethyldiglycol or p-menthane as a solvent can achieve an extremely high contact angle of 80 degrees or more. And storage stability was excellent.
Further, as can be seen from Table 3, the surface treatment liquid 1 using N, N-dimethylaminotrimethylsilane as a silylating agent and diethyldiglycol as a solvent was excellent in substituting property with water. Therefore, it is considered suitable when the surface treatment and the cleaning treatment are performed continuously.

Claims (4)

A step of treating the surface of a resin pattern provided on the substrate or a pattern to be etched formed on the substrate by etching with a surface treatment liquid containing a silylating agent and a solvent;
Cleaning the resin pattern or the pattern to be etched after the treatment with the surface treatment liquid.   The surface treatment method according to claim 1, wherein the content of the silylating agent in the surface treatment liquid is 0.1 to 50% by mass.   The surface treatment method according to claim 1, wherein the silylating agent is N, N-dimethylaminotrimethylsilane (DMATMS).   A surface treatment liquid containing a silylating agent and a solvent and used in the surface treatment method according to claim 1.