JP2005202179A - Method for manufacturing photomask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the manufacturing lead time and cost of a semiconductor integrated circuit device by using a photomask with an organic resin film as a light shielding body usable for KrF excimer laser lithography. <P>SOLUTION: In a photomask manufacturing process, a light shielding body pattern is directly formed using a photosensitive resin composition containing a specified light absorbing compound. Since the light shielding pattern of the photomask for KrF lithography can directly be formed only by a resist step, a light shielding film etching step and a resist removing step are made unnecessary, accordingly cost reduction of the photomask, improvement of dimensional accuracy and diminution of defects can be achieved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an electronic device such as a semiconductor integrated circuit device, a superconducting device, a micromachine, a TFT, or a wiring board, and more particularly to a technique effective when applied to a lithography technique in a manufacturing process of a semiconductor circuit integrated device. is there.

  In the manufacture of a semiconductor integrated circuit device, a lithography technique is used as a method for transferring a fine pattern onto a semiconductor wafer. In lithography technology, a projection exposure apparatus is mainly used, and a photomask pattern mounted on the projection exposure apparatus is transferred onto a semiconductor wafer to form a device pattern.

  A normal photomask is produced by processing a light shielding material such as chromium (Cr) formed on a transparent quartz glass substrate. That is, a light shielding film made of chromium or the like is formed in a desired shape on a quartz glass substrate. An example of the processing of the light shielding film is as follows. That is, an electron beam sensitive resist is applied on the light shielding film, and a desired pattern is drawn on the electron beam sensitive resist using an electron beam drawing apparatus. Thereafter, a resist pattern having a desired shape is formed by development, and etching (dry or wet) is performed using the resist pattern as a mask to process a light shielding film such as chromium. Finally, the resist after the pattern transfer is removed, washed, and the like, and a light shielding pattern having a desired shape is formed on the quartz glass substrate using a light shielding material such as chromium.

  In recent years, for the purpose of improving the resolution of lithography, various mask structures have been proposed in addition to an ordinary photomask in which a light shielding film made of chromium or the like as described above is formed in a desired shape. For example, in Patent Document 1, as an improvement in the resolution of a single transparent pattern, the periphery of the single transparent pattern is translucent, that is, the light-shielding portion of the photomask is translucent, and the slight light passing through the translucent portion It is devised to reverse the phase of the light passing through the transparent pattern. That is, the photomask is such that light having a sensitivity equal to or lower than that of the photoresist to which the pattern is transferred is allowed to pass through the translucent film, and the phase of this light and the light passing through the transparent pattern is reversed. Since the phase of the light that has passed through the semi-transparent film is inverted with respect to the light that has passed through the transparent pattern that is the main pattern, the phase is inverted at the boundary portion, and the light intensity at the boundary portion approaches zero. As a result, the ratio between the intensity of light that has passed through the transparent pattern and the intensity of light at the pattern boundary is increased, and a light intensity distribution with high contrast can be obtained compared to a technique that does not use a translucent film. It is a mechanism to improve. This is called a halftone phase shift mask. In the manufacturing process of the halftone phase shift mask, the light shielding film of the normal photomask is changed to a halftone phase shift film, and manufactured in substantially the same process as the manufacturing process of the normal photomask. .

  There is also an exposure method called super-resolution that enables pattern resolution much smaller than the exposure wavelength. Among these super-resolutions, the Levenson-type phase shift exposure method is most effective for forming a fine pattern. The Levenson-type phase shift exposure method forms a structure called a phase shifter that alternately inverts the phase of exposure light by sandwiching a light shielding portion between the exposure light transmitting portion of a normal photomask, that is, a window portion where the glass surface is exposed. In this method, exposure is performed using this photomask. Since the phase of the light passing through both transmission parts is inverted, there occurs a place where the light amplitude becomes zero at the light shielding part between them. If the amplitude is 0, the light intensity is also 0, the contrast is dramatically improved, and the period of the alternately arranged light-shielding portions and phase shifter portions can be resolved to about 1/2 the exposure wavelength. A photomask having such a light shielding portion and a phase shifter portion is called a Levenson type phase shift mask.

  In recent years, with the increase in accuracy and diversification of semiconductor integrated circuit devices, as a photomask used in lithography technology, even a normal photomask has a stricter processing accuracy, and furthermore, a phase having a special structure as described above. A shift mask is also required. Therefore, the manufacturing cost of about 20 to 40 photomasks that are generally manufactured for manufacturing one kind of semiconductor integrated circuit device is extremely high, and the time required for manufacturing the photomask increases as miniaturization progresses. It has become.

  On the other hand, Patent Document 2 discloses a method of forming a light shielding film in a photomask with a resist film instead of a conventional metal film such as Cr. This method utilizes the property that the main component in an ordinary electron beam resist or photosensitive resist composition has an extremely large light absorption band at the wavelength of an ArF excimer laser light source (approximately 193 nm). Therefore, according to this method, an etching process of the light shielding film and a resist removal process become unnecessary, and the cost of the photomask, the dimensional accuracy can be improved, and the defects can be reduced. Many high-performance resists used in current KrF excimer laser lithography and electron beam lithography use a phenolic polymer resin or a derivative thereof in a polymer resin matrix that provides the coating properties. The aromatic ring (benzene ring) structure in such a resin has an extremely large absorption maximum in the vicinity of the wavelength of ArF excimer laser light. With such a resin coating film, the transmittance at a wavelength of 193 nm is 1 even at a film thickness of only 0.1 μm. % Or less. Therefore, in the case of a resist material having such a resin as a matrix, the transmittance with respect to ArF excimer laser light is 0.01% or less in calculation even if the film thickness is usually about 0.3 μm, which is almost equal to An ideal light shielding film can be obtained. However, the transmittance of such a resin also increases in the vicinity of the wavelength (approximately 248 nm) of the current KrF excimer laser light, and the transmittance is small even at a film thickness (usually about 0.3 to 1.0 μm) that forms a fine pattern. 30% or more. Therefore, these resists cannot be used as they are as a light shielding film for a photomask for KrF excimer laser lithography.

JP-A-4-136854

JP-A-5-289307

  In the above technique in which the light-shielding film in the photomask is formed of a resist film having a large light absorption at the exposure wavelength instead of the conventional metal film such as Cr, it is to be applied to the current photomask for KrF excimer laser lithography. Problems and countermeasures are not disclosed. The subject of this invention is providing the photomask for KrF excimer laser lithography using the light-shielding body pattern using the light absorption characteristic which an organic resin composition has.

  Various types of current high-performance resists have a transmittance of 30% or more in the vicinity of the wavelength of KrF excimer laser light (approximately 248 nm) even with a film thickness (usually about 0.3 to 1.0 μm) that forms a fine pattern. Therefore, these resists cannot be used as they are as the light shielding film of the photomask for KrF excimer laser lithography. A measure that can be easily analogized is to incorporate a compound or chemical structure having an absorption band in the wavelength region of KrF excimer laser light into the current resist composition having high resolution performance. However, a light-absorbing compound that can be incorporated into the composition without significantly degrading the features such as resolution of current resists is not clear. That is, a resist composition in which a resist pattern directly formed on a quartz glass substrate for a photomask can be used as a light shielding body for a photomask for KrF excimer laser lithography, and a photomask for KrF excimer laser lithography using the resist composition can be produced. It is the subject of the present invention.

  The light-shielding body using the light absorption characteristics of the organic resin composition has limitations in durability such as light resistance and heat resistance compared to a light-shielding body made of a metal inorganic film such as Cr used in a normal photomask. . The known technique describes a method for improving the durability by heat treatment after pattern formation. The present inventor has intensively studied the durability of an organic resin composition light-shielding body utilizing light absorption characteristics by a KrF excimer laser exposure apparatus, and has a light absorption band of the exposure wavelength under a long-time exposure environment. It was found that organic resin coatings cannot avoid any photochemical reaction changes or heat changes without exception. Therefore, the new subject of this invention is providing the method of using the photomask which has an organic resin composition light-shielding body in which some photochemical reaction change and heat change cannot be avoided effectively. Furthermore, it is providing the method of improving the light resistance and heat resistance of an organic resin composition light-shielding body.

  In addition to this, a photomask has recently been required to have a very fine pattern such as an OPC pattern, and a fine pattern can be formed, and a resist having a low roughness (high accuracy), that is, a tourist composition is required. Even if the current photoresist has sufficient fine processing characteristics, there remains a problem in the roughness of the pattern side wall, that is, the accuracy. Also, in the resist development process in the current photomask manufacturing process, shower (spray) development is generally applied to improve accuracy. In this developing method, the physical impact on the resist is large, and problems such as a reduction in the resist pattern film occur. Therefore, in addition to the above-described problems, an object of the present invention is to provide a method for producing a photomask using a light-sensitive composition having a small sidewall roughness and excellent development resistance.

  When these heat resistance and development resistance are inferior, unevenness in each process is enlarged, which causes a reduction in mask in-plane dimension controllability (in-plane CD) and resolution. An object of the present invention is to provide a photosensitive composition having good in-plane CD controllability and excellent resolution.

This invention solves each subject for providing the photomask for KrF excimer laser lithography using the light-shielding body pattern using the light absorption characteristic which an organic resin composition has by the means hung up to the following items.
(1) A photosensitive resin coating film capable of forming a resist pattern that can be applied to a photomask for KrF excimer laser lithography instead of a light-shielding pattern made of a metal film such as Cr in a normal photomask has the following general formula It was found that a photosensitive resin composition characterized in that at least one of the compounds represented by formulas (A) to (Chem. 8) is contained in a compound that controls the solubility in an alkali developer can be used.

（ここでR1〜R10は水素、炭素数1〜4の置換または無置換アルキル基、ハロゲン、水酸基、メチロール基、炭素数1〜4の置換または無置換アルコキシ基、ヒドロキシル基、フェニル基、メトキシ基、エトキシエチル基、シクロプロピル基、アセタール基、アセチル基の中から選ばれる原子または原子団を表す。R1〜R10は同一であってもよく、異なっていてもよい。また、Xはハロゲン化アセチル基、Yはカンファースルホネート、トリフルオロスルホネート、メタンスルホネート等の中から選ばれる原子または原子団を表す。）より具体的には、例えばアントラセン、アンスラロビン、ベンゾキノリン、フェナントール、1-メトキシ-9、10-ジブロモアントラセン、２−ヒドロキシメチルアントラセン、９−ヒドロキシメチルアントラセン、９−ブロモアントラセン、9−クロロメチルアントラセン、メトキシメチルアントラセン、1-アミノアントラセン、アセトキシアントラセン、1-ナフトール、2-ナフトール、1、2-ジヒドロキシナフタレン、1、3-ジヒドロキシナフタレン、1、4-ジヒドロキシナフタレン、1、5-ジヒドロキシナフタレン、1、6-ジヒドロキシナフタレン、1、7-ジヒドロキシナフタレン、1、8-ジヒドロキシナフタレン、2、3-ジヒドロキシナフタレン、2、4-ジヒドロキシナフタレン、2、5-ジヒドロキシナフタレン、2、6-ジヒドロキシナフタレン、2、7-ジヒドロキシナフタレン、2、8-ジヒドロキシナフタレン、2-ブロモアセチルナフタレン、2-ブロモアセチル-6、7-ジメトキシナフタレン、1-ヒドロキシ-4-ブロモ-2-ブロモアセチルナフタレン、1.3.5-トリス（ブロモアセチル）ベンゼン、3-ブロモアセチルクマリン、3-ブロモメチル-7-メトキシ-1、4-ベンゾキサジン-2-オンなどが挙げられる。

(Where R1 to R10 are hydrogen, substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, halogen, hydroxyl group, methylol group, substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms, hydroxyl group, phenyl group, methoxy group Represents an atom or atomic group selected from ethoxyethyl group, cyclopropyl group, acetal group and acetyl group, R1 to R10 may be the same or different, and X is an acetyl halide Group, Y represents an atom or atomic group selected from camphorsulfonate, trifluorosulfonate, methanesulfonate, etc.) More specifically, for example, anthracene, anthrarobin, benzoquinoline, phenanthol, 1-methoxy-9, 10-dibromoanthracene, 2-hydroxymethylanthracene, 9-hydroxymethylanthracene, 9-bromo Nthracene, 9-chloromethylanthracene, methoxymethylanthracene, 1-aminoanthracene, acetoxyanthracene, 1-naphthol, 2-naphthol, 1,2-dihydroxynaphthalene, 1,3-dihydroxynaphthalene, 1,4-dihydroxynaphthalene, 1 , 5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 1,8-dihydroxynaphthalene, 2,3-dihydroxynaphthalene, 2,4-dihydroxynaphthalene, 2,5-dihydroxynaphthalene, 2, 6-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 2,8-dihydroxynaphthalene, 2-bromoacetylnaphthalene, 2-bromoacetyl-6, 7-dimethoxynaphthalene, 1-hydroxy-4-bromo-2-bromoacetylnaphthalene 1.3.5-Tris (bromoacetyl) benzene, 3-bromide Acetyl coumarin, 3-bromomethyl-7-methoxy-1,4-benzoxazin-2-one and the like.

Even in this case, at the KrF excimer laser beam wavelength, it is difficult to obtain performance equivalent to the extremely large light absorption characteristics at the ArF excimer laser beam wavelength exhibited by various current resists using ordinary aromatic ring-containing resins as a matrix. It was. However, if the content of the light-absorbing compound and the film thickness are adjusted and the transmittance of the formed light-shielding body pattern portion with respect to KrF excimer laser light is 1% or less, more preferably 0.5% or less, it is used for KrF excimer laser lithography. It can be used as a photomask.
(2) It has been found that a photosensitive resin composition having a hydroxyl group as a substituent and a non-chain compound having a molecular weight of 500 to several thousand as a base resin is effective for forming a pattern with little sidewall roughness. It was.
(3) A compound having at least two enol ether groups is added to the photosensitive resin composition in order to improve the heat resistance of the photomask using the photosensitive composition as a light-shielding body and in addition to improve the development resistance. I found it effective. It is essential that this compound is crosslinked with the above non-chain compound by heat, and the crosslinking is cleaved by an acid generated by exposure. Specific examples include those synthesized by the reaction of a polyhydric alcohol represented by ethylene glycol divinyl ether, pentaerythritol divinyl ether and the like and a halogenated alkyl vinyl ether, represented by the following general formulas (Chemical Formula 9) to (Chemical Formula 12). However, it is not limited to those synthesized by the reaction of polyhydric phenols and halogenated alkyl vinyl ethers. The addition amount is preferably 1 part by weight or more with respect to 100 parts by weight of the resin.

また、（２）上記光吸収化合物を含む感光性樹脂組成物は、ＫｒＦエキシマレーザーリソグラフィにおけるハーフトーン型位相シフトマスク作製にも適用できる。すなわち、組成物中の光吸収化合物の含有量及び膜厚を調整し、形成した遮光体パターン部のＫｒＦエキシマレーザー光に対する透過率が２％から１６％の範囲、より好ましくは４％から９％の範囲であればＫｒＦエキシマレーザーリソグラフィ用ハーフトーン型位相シフトマスクとして使用可能である。
（４）上記（１）、（２）、（３）各項で使用される感光性樹脂組成物の遮光部パターン形成には、通常のフォトマスク製造に使用される電子線描画や波長３６３．８ｎｍのＡｒイオンレーザーを光源とするレーザー描画技術が使用できる。本発明の感光性樹脂組成物は上記（１）項で示された光吸収化合物を含有することによりＫｒＦエキシマレーザー光の波長域に光吸収帯を有する。そのためこの領域でのパターン露光により微細パターンを解像するのは不利である。一般に良好な解像性能を示すレーザー光等活性化学線の露光波長は、そのレジスト（感光性樹脂）塗膜で充分基板面まで透過する波長を用いるべきである。本発明の組成物では、４０％以上の透過率をしめす紫外線等をパターン露光に使用すれば良好な遮光体パターンを解像・形成できる。通常のフォトマスク基板では、周辺部に遮光域が形成されているが、これは使用する石英ガラス基板にあらかじめ恒久的なＣｒ等金属膜で形成してあればより好ましい。このようなマスク基板は、用済み後、有機樹脂遮光体パターン部を除去し、再生利用することが出来る。
（５）本発明のポジ型感光性樹脂組成物には、公知の化学増幅系ポジ型レジストの組成が利用できる。代表的な化学増幅系ポジ型レジスト組成は、２成分系と３成分系があり、２成分系としては水性アルカリ可溶性樹脂に保護基を導入した樹脂、酸発生剤からなり、３成分系としては水性アルカリ可溶性樹脂、溶解阻害剤、酸発生剤からなる。本発明のポジ型感光性樹脂組成物は、こうした組成中の樹脂が上記（１）で示した光吸収化合物を少なくとも一種類含有したものであり、（２）で示した条件を満たすものである。
（６）本発明の感光性樹脂組成物にＫｒＦエキシマレーザー光の光吸収帯を付与する光吸収化合物としては（１）項に記述した化合物が上げられるが、特にアントラセン誘導体またはナフトール誘導体が効果的であった。アントラセンあるいはナフトールの分子構造がＫｒＦエキシマレーザー光の波長域に特に大きな吸収帯を有するためである。
（７）本発明の樹脂組成物を用いて、シリコン基板上にLSIパターンを形成することも可能であり、低分子非鎖状樹脂を用いているため、ラフネスの小さなパターンが形成可能であり、極微細な高精度のパターン形成が可能である。この場合には、必ずしもKrF光に吸収を持つ置換基を導入する必要はない。

Moreover, (2) The photosensitive resin composition containing the said light absorption compound is applicable also to preparation of the halftone type phase shift mask in KrF excimer laser lithography. That is, by adjusting the content and film thickness of the light absorbing compound in the composition, the transmittance of the formed light-shielding body pattern portion with respect to KrF excimer laser light is in the range of 2% to 16%, more preferably 4% to 9%. Can be used as a halftone phase shift mask for KrF excimer laser lithography.
(4) For the light-shielding part pattern formation of the photosensitive resin composition used in the above items (1), (2), (3), electron beam drawing or wavelength 363. Laser drawing technology using an 8 nm Ar ion laser as a light source can be used. The photosensitive resin composition of the present invention has a light absorption band in the wavelength region of KrF excimer laser light by containing the light absorbing compound shown in the above item (1). Therefore, it is disadvantageous to resolve a fine pattern by pattern exposure in this region. In general, an exposure wavelength of an active actinic ray such as a laser beam exhibiting a good resolution performance should be a wavelength that allows the resist (photosensitive resin) coating to sufficiently transmit to the substrate surface. In the composition of the present invention, a good light-shielding body pattern can be resolved and formed by using ultraviolet rays or the like having a transmittance of 40% or more for pattern exposure. In a normal photomask substrate, a light-shielding area is formed in the peripheral portion, but it is more preferable that the quartz glass substrate to be used is previously formed of a permanent metal film such as Cr. After such a mask substrate is used, the organic resin light-shielding body pattern portion can be removed and recycled.
(5) A known chemical amplification positive resist composition can be used for the positive photosensitive resin composition of the present invention. Typical chemical amplification type positive resist compositions include a two-component system and a three-component system. The two-component system includes a resin in which a protective group is introduced into an aqueous alkali-soluble resin and an acid generator. It consists of an aqueous alkali-soluble resin, a dissolution inhibitor, and an acid generator. The positive photosensitive resin composition of the present invention is such that the resin in such a composition contains at least one kind of light absorbing compound shown in (1) above and satisfies the condition shown in (2). .
(6) As the light absorbing compound for imparting the light absorption band of KrF excimer laser light to the photosensitive resin composition of the present invention, the compounds described in the item (1) can be mentioned, and anthracene derivatives or naphthol derivatives are particularly effective. Met. This is because the molecular structure of anthracene or naphthol has a particularly large absorption band in the wavelength region of KrF excimer laser light.
(7) Using the resin composition of the present invention, it is possible to form an LSI pattern on a silicon substrate, and since a low-molecular non-chain resin is used, a pattern with small roughness can be formed. Very fine high-precision pattern formation is possible. In this case, it is not always necessary to introduce a substituent having absorption in KrF light.

  According to the present invention, since the light-shielding body pattern of the photomask for KrF lithography can be directly formed only by the resist process, the process of etching the light-shielding film and the process of removing the resist become unnecessary, reducing the cost of the photomask, improving the dimensional accuracy, Defect reduction is possible. In addition, since it is possible to use a photomask having a low cost and a short manufacturing time as needed, there is an effect that a small amount of various types of semiconductor integrated circuit devices can be manufactured in a short time and at a low cost.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited only to these examples.

<Synthesis Example 1>
In 50 ml of dimethyl sulfoxide, 6.0 g of polynuclear phenol compound TPPA-1000P (made by Honshu Chemical Industry Co., Ltd.), 2.45 g of 9-hydroxymethylanthracene, 0.61 g of potassium hydroxide, and 0.36 g of tetrabutylammonium bromide are dissolved. The mixture was stirred at 65 ° C. for 6 hours. To the solution are added 300 ml of ethyl acetate, 0.02 g of hydrochloric acid and 100 ml of water, and the mixture is separated. The organic layer is washed twice with 200 ml of water, the solvent is dried under reduced pressure, and 7.0 g of anthracene-containing TPPA-1000P (yellow solid) is added. Obtained. 3 g of the anthracene-containing TPPA-1000P was dissolved in 100 ml of ethyl acetate, 4.0 g of 3,4-dihydro-2H-pyran and 0.02 g of hydrochloric acid were added, and the mixture was stirred at room temperature for 20 hours. To the solution was added 100 ml of 2% aqueous potassium hydroxide solution, the organic layer was washed three times with 100 ml of water, the solvent was dried under reduced pressure, and 3.5 g of THP-anthracene-containing TPPA-1000P (yellow solid) was added. Obtained.

<Example 1>
As shown in Synthesis Example 1, THP-anthracene-containing TPPA-1000P: 100 parts by weight, triphenylsulfonium perfluoroantimonate 10 parts by weight as an acid generator, and acid-decomposable thermally crosslinkable compound Compound: 4 parts by weight were dissolved in 2-heptanone, and this was filtered through a Teflon (registered trademark) membrane filter having a pore diameter of 0.2 μm to prepare a positive photosensitive resin composition solution. This solution was dropped on a silicon wafer, spin-coated, and then heat treated at 120 ° C. for 10 minutes to obtain a coating film having a thickness of 0.5 μm. After drawing a test pattern with an electron beam drawing device (electron beam acceleration voltage is 50 kV), heat treatment at 100 ° C. for 2 minutes, and then using a tetramethylammonium hydroxide (2.38%) aqueous solution as a developer for 60 seconds. When developed, the film loss was 2 nm, and a good positive pattern of 0.15 μm was obtained at an electron beam dose of 12.0 μC / cm ² . Further, the in-plane CD at that time was as good as 12.2 nm in the range. Further, a coating film was formed on a quartz glass plate having a thickness of 1 mm by a spin coating method, and after heating at 120 ° C. for 10 minutes on a hot plate, the absorbance at a wavelength of 248 nm was measured. 6.2. Even when a post-baking temperature of 130 ° C. for 2 minutes after patterning was added, the shape was a beautiful rectangle.

<Example 2>
The same work as in Example 1 was performed except that the acid-decomposable thermal crosslinking agent was (Chemical Formula 10): 6 parts by weight. As a result, the amount of film loss after shower development was 4 nm, A good positive pattern of 0.15 μm was obtained at 0.0 μC / cm ² . Further, the in-plane CD at that time was as good as 12.5 nm in the range. Even when a post-baking temperature of 130 ° C. for 2 minutes after patterning was added, the shape was a beautiful rectangle.

<Example 3>
When the same operation as in Example 1 was performed except that the substituent in the resin composition of Example 1 was changed from anthracene to hydroxynaphthoic acid, the amount of film loss after shower development was 4 nm, the electron beam irradiation amount, A good positive pattern of 0.16 μm was obtained at 11.0 μC / cm ² . Further, the in-plane CD at that time was as good as 19 nm in the range. Even when a post-baking temperature of 130 ° C. for 2 minutes after patterning was added, the shape was a beautiful rectangle.

<Example 4>
The same operation as in Example 3 was performed except that trimethylsulfonium perfluoroantimonate was used as the acid generator. As a result, the film loss after shower development was 4 nm, the electron beam irradiation amount was 12.5 μC / A good positive pattern of 0.15 μm was obtained at cm ² . Further, the in-plane CD at that time was as good as 18 nm in the range. Even when a post-baking temperature of 130 ° C. for 2 minutes after patterning was added, the shape was a beautiful rectangle.

<Comparative Example 1>
When the same operation as in Example 1 was performed except that the acid-decomposable heat-crosslinking compound was not added, the film loss after shower development was 28 nm. A positive pattern of 0.4 μm at an electron beam dose of 10.0 μC / cm ² was the resolution limit. At that time, the in-plane CD deteriorated to 55 nm in the range. In addition, when the post-baking temperature after patterning was 110 degrees 2 minutes, the pattern was deformed into a dome shape.

<Example 5>
An example of a method for producing a photomask for KrF excimer laser lithography using the positive photosensitive resin composition prepared in Example 1 will be described with reference to FIG. FIGS. 1A to 1E schematically show process cross-sectional views of manufacturing a photomask for KrF excimer laser lithography according to the present invention. FIG. 1A shows a cross-sectional view of a photomask substrate used in the present invention. Here, 101 is a quartz glass substrate, and 102 is a substrate peripheral area light shielding body made of a metal film such as Cr provided in advance. This portion does not become a circuit pattern transfer region in the lithography process. Thus, the photomask substrate in a state before the circuit pattern is formed is referred to as blanks. FIG.1 (b) represents the cross section which apply | coated the positive type photosensitive resin composition prepared in Example 1 on the blanks. Here, the positive photosensitive resin composition is applied by a spin coating method and heated for 10 minutes on a hot plate adjusted to 120 ° C. to form a photosensitive resin composition layer 103 having a thickness of 0.6 μm. did. Next, as shown in FIG. 1C, a water-soluble conductive film 104 for preventing pattern shift due to charge-up during electron beam drawing was applied. FIG. 1D is a schematic cross-sectional view in which a desired pattern shape is irradiated with an electron beam 105 by an electron beam drawing apparatus, and a latent image 106 having a desired pattern is formed on the photosensitive resin layer 103. At this time, the acceleration voltage of the electron beam was 50 kV, and the irradiation amount was 12 μC / cm ² . The substrate taken out from the electron beam irradiation apparatus was heated on a hot plate adjusted to 100 ° C. for 10 minutes, and then developed for 60 seconds using a 2.38% aqueous solution of tetramethylammonium hydroxide as a developer. After rinsing with water and drying, a desired positive pattern 107 was obtained as shown in FIG. A 0.8 μm line & space pattern could be satisfactorily resolved on the blanks. This corresponds to a microfabrication dimension of 0.16 μm on a semiconductor substrate in a 5: 1 reduction projection exposure type KrF stepper. The transmittance of the pattern portion of the formed positive resist at a wavelength of 248 nm was 0.3%. The obtained photomask had a transfer performance equivalent to that of an ordinary photomask for KrF lithography using a metal such as Cr.

  FIG. 5 shows an enlarged part of a plan view of the mask produced at this time. A cross-sectional view thereof is shown in FIG. It can be seen that a clear rectangular light shielding pattern 107 is formed. The mask in-plane CD at this time was 12.2 nm.

<Comparative example 2>
A mask was prepared in the same procedure as in Example 5 except that the positive photosensitive resin composition prepared in Comparative Example 1 was used instead of the positive photosensitive resin composition prepared in Example 1. FIG. 7 shows an enlarged partial plan view of the mask produced at this time. A cross-sectional view thereof is shown in FIG. It can be seen that the light-shielding body pattern 107 is reduced in film thickness, and the line width is thicker than that of the electron beam irradiation pattern 114 and the shape is changed to a round shape. In addition, there is a slight difference in film thickness between the light shielding element patterns. For this reason, the mask in-plane CD at this time was as large as 55.0 nm.

<Example 6>
This will be described with reference to FIG. In the figure, 101 is quartz glass, 107 is a resist, 108 is exposure light (KrF excimer laser light), 109 is a projection lens, 110 is a wafer, 111 is a film to be processed, 112 is an antireflection film, and 113 is a resist. . Here, the photomask described in Example 5 was used. Although the oxide film is used as an example of the film to be processed 111, the present invention is not limited thereto, and a metal film such as W or Al, a polysilicon film, a nitride film, a carbide film, or the like may be used. The coating type organic film is used here as the antireflection film 112, but the present invention is not limited to this, and an inorganic film such as SiON may be used. In addition, although the transfer dimensional accuracy is lowered, it is possible to omit the antireflection film. By such an exposure method, the mask using the photosensitive resin composition was able to transfer an equivalent pattern without any problem even after irradiation with 100 J / cm ^{2 of} KrF laser light (248 nm).

<Example 7>
Embodiment 7 relates to the manufacture of a semiconductor integrated circuit device having a twin well type CMIS (Complementary MIS) circuit, and will be described with reference to FIG.
FIG. 3 is a fragmentary cross-sectional view of the semiconductor wafer during the manufacturing process. The semiconductor substrate 3s constituting the semiconductor wafer is made of, for example, a Si single crystal having a circular n-type plane. In the upper part, for example, an n well 6n and a p well 6p are formed. For example, an n-type impurity such as phosphorus or As is introduced into the n-well 6n. Further, p-type impurities such as boron are introduced into the p-well 6p. The n well and p well are formed as follows. First, a wafer alignment mark for mask alignment is formed on the semiconductor substrate 3s (not shown). This wafer alignment mark can also be formed at the time of well formation by adding a selective oxidation step. Thereafter, as shown in FIG. 3A, an oxide film 17 is formed on the semiconductor substrate 3s, and subsequently, a resist pattern 18 for an implantation mask is formed on the oxide film 17. Then phosphorus was implanted. In forming the resist pattern 18 for the implantation mask, a KrF reduced projection exposure apparatus and a KrF photomask using the resist pattern described in Example 5 as a light shielding body were used. After that, ashing is performed to remove the resist 18 and the oxide film 17 is removed. Then, as shown in FIG. 3B, an oxide film 19 is formed on the semiconductor substrate 3s, and the resist pattern 20 for the implantation mask is subsequently oxidized. It is formed on the film 19. Then phosphorus was implanted. For the formation of the resist pattern 20 for the implantation mask, a KrF reduced projection exposure apparatus and a KrF photomask using the resist pattern described in Example 5 as a light shielding body were used. Thereafter, the resist 20 and the oxide film 19 are removed, and a separation field insulating film 7 made of, for example, a silicon oxide film is formed in the form of groove type isolation on the main surface (first main surface) of the semiconductor substrate 3s. (Fig. 4 (c)).
As an isolation method, a LOCOS (Local Oxidization of Silicon) method may be used. However, the LOCOS method has a problem that the layout dimension becomes large due to the reason that the bird's beak is extended. For the lithography at the time of creating the isolation, a KrF excimer laser reduced projection exposure apparatus and a photomask for a KrF excimer laser using the resist pattern described in Example 5 as a light shield were used. In the active region surrounded by the field insulating film 7, nMISQn and pMISQp are formed. The gate insulating film 8 of nMISQn and pMISQp is made of, for example, a silicon oxide film, and is formed by a thermal oxidation method or the like. The gate electrode 9 of nMISQn and pMISQp is formed by depositing a gate forming film made of, for example, low-resistance polysilicon by a CVD method or the like, and then depositing the film on the KrF excimer laser reduced projection exposure apparatus and the resist pattern described in Example 5 Lithography is performed using a photomask for a KrF excimer laser with a light shielding body, and etching is performed thereafter. The semiconductor region 10 of the nMISQn is formed in a self-aligned manner with respect to the gate electrode 9 by introducing, for example, phosphorus or arsenic into the semiconductor substrate 3s using the gate electrode 9 as a mask by an ion implantation method or the like. Further, the semiconductor region 11 of the pMISQp is formed in a self-aligned manner with respect to the gate electrode 9 by introducing, for example, boron into the semiconductor substrate 3s by the ion implantation method or the like using the gate electrode 9 as a mask. However, the gate electrode 9 is not limited to being formed of, for example, a single film of low resistance polysilicon, and can be variously modified. For example, tungsten silicide, cobalt silicide, or the like is formed on the low resistance polysilicon film. A so-called polycide structure may be formed by providing such a silicide layer, or a metal film such as tungsten is provided on a low resistance polysilicon film via a barrier conductor film such as titanium nitride or tungsten nitride. A so-called polymetal structure may be used.

  First, on such a semiconductor substrate 3s, as shown in FIG. 3D, an interlayer insulating film 12 made of, for example, a silicon oxide film is deposited by a CVD method or the like. Subsequently, the polysilicon film is subjected to lithography using a KrF excimer laser reduced projection exposure apparatus and a photomask for a KrF excimer laser using the above resist pattern as a light shield, patterned by etching, and then patterned. By introducing impurities into a predetermined region of the polysilicon film, a wiring 13L and a resistor 13R made of the polysilicon film are formed. After that, as shown in FIG. 4E, for example, a silicon oxide film 14 is deposited on the semiconductor substrate 3s by a CVD method or the like, and then the semiconductor regions 10 and 11 and the wiring 13L are formed on the interlayer insulating film 12 and the silicon oxide film 14. The connection hole 15 in which a part of the contact hole 15 is exposed is subjected to lithography using a KrF excimer laser reduced projection exposure apparatus and a mask for a KrF excimer laser using the resist pattern of Example 5 described above as a light shielding body, and etched to form a hole. Open. Further, after sequentially depositing a metal film made of titanium, titanium nitride, and tungsten on the semiconductor substrate 3s by sputtering and CVD, the metal film is made a KrF excimer laser reduced projection exposure apparatus and the above resist pattern as a light shielding body. Lithography is performed using a photomask for a KrF excimer laser, and etching is performed to form the first layer wiring 16L1 as shown in FIG. Thereafter, the second layer wiring and subsequent layers were formed in the same manner as the first layer wiring 16L1, and the semiconductor integrated circuit device was manufactured.

Sectional drawing which shows the manufacturing process of the photomask for KrF lithography using the organic resin light-shielding body of this invention. Explanatory drawing which shows the structure of this invention. The principal part sectional drawing of the semiconductor wafer in the manufacturing process of a semiconductor integrated circuit device. The top view which shows a part of photomask for KrF lithography using the organic resin light-shielding body of this invention. Sectional drawing which shows a part of photomask for KrF lithography using the organic resin light-shielding body of this invention. FIG. 6 is a plan view showing a part of a photomask manufactured in Comparative Example 2. Sectional drawing which shows a part of photomask produced in the comparative example 2. FIG.

Explanation of symbols

R1 to R10: hydrogen, substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, halogen, hydroxyl group, methylol group, substituted or unsubstituted alkoxy group having 1 to 4 carbon atoms, hydroxyl group, phenyl group, methoxy group, ethoxyethyl Atom or atomic group selected from a group, cyclopropyl group, acetal group, and acetyl group (R1 to R10 may be the same or different. X is a halogenated acetyl group, Y is camphorsulfonate. Represents an atom or atomic group selected from trifluorosulfonate, methanesulfonate, and the like.
3 ... Semiconductor substrate, 6n ... n well, 6p ... p well, 7 ... Field insulating film, 8, 9 ... Gate insulating film, 10 ... Semiconductor region of nMISQn, 11 ... Semiconductor region of pMISQp, 12 ... Interlayer insulating film, 13L ... wiring, 13R ... resistance, 14 ... HLD (silicon oxide) film, 15 ... connection hole, 16L1 ... first layer wiring, 101 ... quartz glass substrate, 102 ... Cr, 103 ... photosensitive resin composition layer, 104 ... water-soluble Conductive film, 105 ... irradiated electron beam having a predetermined pattern shape, 106 ... latent image, 107 ... light shielding pattern, 108 ... exposure light, 109 ... projection lens, 110 ... wafer, 111 ... work film, 112 ... antireflection film 113 ... Resist, 114 ... Electron beam irradiation pattern.

Claims (4)

In a photomask manufacturing method having a light-shielding body portion made of a photosensitive resin coating film having a desired pattern formed on a quartz glass substrate,
The photosensitive resin coating film has optical characteristics such that the transmittance of the light shielding part to KrF excimer laser light is 1% or less, more preferably 0.5% or less,
The composition of the photosensitive resin coating film comprises (a) a non-chain low molecular compound having a molecular weight of 500 or more and several thousand or less, (b) an acid-decomposable thermally crosslinkable compound, and (c) an acid generator. A method for producing a photomask using a photosensitive resin composition, wherein the compositions (a) and (b) are crosslinked.   2. The method for producing a photomask according to claim 1, wherein the non-chain low molecular compound in the composition (a) has a hydroxyl group. The non-chain low molecular compound in the composition (a) contains at least one compound represented by the following general formulas (Chemical Formula 1) to (Chemical Formula 8) as a substituent. The photomask manufacturing method as described.

  The photomask manufacturing method according to claim 1 or 2, wherein the acid-decomposable thermally crosslinkable compound in the composition (b) comprises a compound having at least two enol ether groups.

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