JP4198778B2 - Manufacturing method of semiconductor device - Google Patents

Description

【００９０】
実施例１９．
実施例１で得た第１のレジストパターンが形成されたＳｉウェハー上に、実施例１４で得た樹脂を第２のレジスト材料として滴下、スピンコートした後、９０℃／７０秒でプリベークを行い、第２のレジスト膜を形成した。
次に、１３５℃／７０秒でミキシングベーク（ＭＢ）を行い、架橋反応を進行させた。次に、イソプロパノール１０％を含む純水溶液を用いて現像を行い、非架橋層を現像剥離し、続く１２０℃／９０秒でポストベークを行うことにより、図１１に示すように、第１のレジストホールパターン上に第２のレジスト架橋層を形成した。
これにより、本実施例における樹脂の分散度とレジストパターンサイズ等の関係を示す表２から、重量平均分子量がほぼ等しい樹脂については、その分散度が現像後の残渣に影響を与えていることが判った。
【００９１】
【表２】

【００９２】
さらには、架橋層を形成したレジストラインのテーパ角も分散度が低い樹脂の方が初期の角度に近い値を示している。なお、テーパ角の測定には図１における（ｆ）パターンを用いた。
また、架橋反応に寄与する官能基（架橋基）数が多い架橋剤を用いるほど、レジストパターンの縮小率も高いが、構成する樹脂の分散度が大きいと現像残渣が顕著に観察される。
【００９３】
実施例２０．
実施例２で得た第１のレジストパターンが形成されたＳｉウェハー上に、実施例１５で得たポリビニルメチルシルセスキオキサン樹脂溶液を第２のレジストとして用いた。
第２のレジスト材料を滴下、スピンコートした後、８０℃／７０秒でプリベークを行い、第２のレジスト膜を形成した。
次に、１００℃／９０秒、１１０℃／９０秒、１２０℃／９０秒の三種類の条件でミキシングベーク（ＭＢ）を行い、架橋反応を行った。次に、ヘキサンを用いて現像を行い、非架橋層を現像剥離し、続く９０℃／９０秒でポストベークを行うことにより、図１１に示すように、第１のレジストパターン上に第２のレジスト架橋層を形成した。
その結果、実施例２で形成した０．４μｍサイズのホールパターンの内径および、ラインパターンと孤立残しパターンにおけるスペースのサイズが、架橋層形成後のレジストパターンでは、表３に示すように縮小されており、その縮小量は、ＭＢ温度が高くなるとともに増大している。
【００９４】
【表３】

【００９５】
このことから、ＭＢの温度制御により、精度良く架橋反応の制御が可能であることが分かる。
【００９６】
実施例２１．
実施例３で得た第１のレジストパターンが形成されたＳｉウェハーを１１０℃でキュアした後、そのウエハ上に、実施例１６で得たポリビニルアセタール溶液を第２のレジストとして用いた。
第２のレジスト材料を滴下、スピンコートした後、８５℃／７０秒でプリベークを行い、第２のレジスト膜を形成した。
次に、６５℃／７０秒＋１００℃／９０秒でミキシングベーク（ＭＢ）を行い、架橋反応を行った。次に、純水を用いて現像を行い、非架橋層を現像剥離し、続く９０℃／９０秒でポストベークを行うことにより、図１２に示すように、第１のレジストパターン上に第２のレジスト架橋層を形成した。
その結果、実施例３で形成した約０．２７μｍサイズのホールパターンの内径は、本実施例における架橋剤の重合度とレジストパターン等の関係を示す表４からあきらかなように縮小されており、その縮小量は、重合度の増加と共に小さくなる。
【００９７】
【表４】

【００９８】
このことから、架橋剤の単一重合体を用いることにより、精度良く架橋反応の制御が可能であることが分かる。
【００９９】
実施例 ２２．
実施例４で得た第１のレジストパターンが形成されたＳｉウェハー上に、実施例１７で得たポリビニルアセタール溶液を第２のレジストとして用いた。
第２のレジスト材料を滴下、スピンコートした後、８５℃／７０秒でプリベークを行い、第２のレジスト膜を形成した。
次に、７０℃／７０秒＋１１０℃／９０秒でミキシングベーク（ＭＢ）を行い、架橋反応を行った。次に、純水を用いて現像を行い、非架橋層を現像剥離し、続く８５℃／９０秒でポストベークを行うことにより、図１２に示すように、第１のレジストパターン上に第２のレジスト架橋層を形成した。
その結果、本実施例における架橋剤の重合度分布とレジストパターン等の関係を示す表５から、実施例４で形成した約０．２８μｍサイズのホールパターンの内径は、縮小されており、その縮小量は、架橋剤構成が低重合度のものが多いほど架橋に関与する置換基を多く含むため大きいことがわかる。
【０１００】
【表５】

【０１０１】
このことから、異なる重合度の架橋剤の混合比の違いにより、架橋反応の制御が可能であることが分かる。
【０１０２】
実施例２３．
実施例３で得た第１のレジストパターンが形成されたＳｉウェハーを１１５℃で９０秒キュアする前処理をした後、そのウエハ上に、実施例１５で得た１，３―ジ（Ｎ―メトキシメチル）ー４ーヒドロキシー２ーイミダゾリジノン含有のポリビニルメチルシルセスキオキサン溶液にＮＭＰを１０％になるように添加した溶液、実施例１６で得た１，３―ジ（Ｎ―メトキシメチル）ー４，５ージヒドロキシー２ーイミダゾリジノンのモノマーを含有するポリビニルアセタール樹脂溶液にイソプロパノールを計２０％になるように滴下した溶液を第２のレジストとして用いた。
第２のレジスト材料を滴下、スピンコートした後、８０℃／７０秒でプリベークを行い、第２のレジスト膜を形成した。
次に、８５℃／７０秒＋１１０℃／９０秒でミキシングベーク（ＭＢ）を行い、架橋反応を行った。次に、ポリビニルメチルシルセスキオキサン樹脂膜についてはＮＭＰを１０％含むキシレン溶液で、ポリビニルアセタール樹脂膜についてはイソプロパノールを２０％含む純水を用いて現像を行い、非架橋層を現像剥離し、続く１１０℃／９０秒でポストベークを行うことにより、図１２に示すように、第１のレジストパターン上に第２のレジスト架橋層を形成した。
その結果、本実施例における前処理の効果を示す表６からあきらかなように、実施例３で形成した約０．２７μｍサイズのホールパターンの内径は、縮小されているが、その縮小量は第１のレジストパターンの前処理（熱処理）をしなかった場合、第２のレジスト塗布時に下地の第１のレジストのダレや溶解が生じ、悪影響を及ぼした。
【０１０３】
【表６】

【０１０４】
このことから、第１のレジストパターンを予め熱処理することにより、第２のレジストの溶剤や現像液をある程度用いる溶媒の種類や混合比に幅ができるため、その構成する樹脂の選択が広がる。
【０１０５】
実施例２４．
実施例６の重量平均分子量が約３万で分散度が２のポリビニルアルコール溶液１８０ｇに、実施例１１で得た１，３―ジ（Ｎ―メトキシメチル）ー４，５ージヒドロキシー２ーイミダゾリジノンのモノマー溶液２０ｇを室温で６時間混合攪拌し、樹脂と架橋剤の混合溶液を得て、これを第２のレジストとして用いた。実施例３で得た第１のレジストパターンが形成されたＳｉウェハー上に、第２のレジスト材料を滴下、スピンコートした後、９０℃／７０秒でプリベークを行い、第２のレジスト膜を形成した。
次に、９０℃／９０秒、１００℃／９０秒、１１０℃／９０秒、１２０℃／９０秒でミキシングベーク（ＭＢ）を行い、架橋反応を行った。次に、純水を用いて現像を６０秒、９０秒、１２０秒、１８０秒を行い、非架橋層を現像剥離し、続く１１５℃／９０秒でポストベークを行うことにより、図１２に示すように、第１のレジストパターン上に第２のレジスト架橋層を形成した。
その結果、本実施例におけるプロセスマージンの効果を示す表７からあきらかなように、実施例３で形成した約０．２７μｍサイズのホールパターンの内径は、縮小されているが、低分散で比較的低分子量の樹脂と単一の低重合度の架橋剤を用いることで、ＭＢ温度と現像時間のマージンが拡大した。
【０１０６】
【表７】

【０１０７】
比較として、分散度が１０で重量平均分子量が３０万のポリビニルアルコールを用いた場合と、１，３―ジ（Ｎ―メトキシメチル）ー４，５ージヒドロキシー２ーイミダゾリジノンのオリゴマーを架橋剤として用いた場合についても記載した。重量平均分子量が３０万のポリビニルアルコールや架橋剤にオリゴマーを用いた際には、現像残渣が見られるものがあり、また条件によっては現像後にホールが開口しておらず測定できないものも観察された。なお、表７中太枠で囲んだ部分は現像残渣がある。
このことから、第２のレジスト材料の分子量、分散度や重合度を換えることにより、ある程プロセスマージンを広げることが出来る。
【０１０８】
実施例２５．
実施例２で得た第１のレジストパターンを酸化膜が形成されたＳｉウエハ上に形成し、図１３に示すような第１のレジストパターンを形成した。
次に実施例１３で得た第２のレジスト材料を滴下し、スピンコートした後、８０℃／７０秒でプリベークを行った後、１１０℃／７０秒でミキシングベーク（ＭＢ）を行い、架橋反応を進行させた。次に、純水を用いて現像を行い、非架橋層を現像剥離し、続く１０５℃／９０秒でポストベークを行うことにより、第１のレジストホールパターン上に第２のレジスト架橋層を形成した。
さらに、エッチング装置を用いて下地酸化膜をエッチングし、エッチング後のパターン形状を観察した。
また、比較例として、本発明の処理を施さない図１３に示した第１のレジストパターンを形成したウエハ（表中レジストのみ）についても同様にエッチングした。その結果、表８に示すように本発明を適用した場合には分離幅は縮小された。
【０１０９】
【表８】

【０１１０】
以上、説明してきたように、本発明ではレジストの分離パターン、ホールパターンの微細化に於て、波長限界を越えるパターン形成を可能とする微細分離レジストパターン形成用材料とそれを用いた微細パターン形成方法が得られる。
これにより、ホール系レジストパターンのホール径を従来より縮小することができ、またスペース系レジストパターンの分離幅を従来より縮小することができる。
また、このようにして形成した微細分離レジストパターンをマスクとして用いて、半導体基板上に微細分離されたスペースまたはホール形成することができる。
また、このような製造方法により、微細分離されたスペースまたはホールを有する半導体装置を得ることができる。
【０１１１】
【発明の効果】
本発明の半導体装置の製造方法によれば、現像残渣の解消、パターン形状の改善、およびプロセスマージンの拡大が実現されるという効果がある。
【図面の簡単な説明】
【図１】 本発明の実施の形態に用いるマスクパターン図である。
【図２】 本発明の実施の形態１のレジストパターン形成方法を説明するための工程フロー図である。
【図３】 本発明の実施の形態１のレジストパターン形成方法を説明するための工程フロー図である。
【図４】 本発明の実施の形態１のレジストパターン形成方法を説明するための工程フロー図である。
【図５】 本発明の実施の形態２のレジストパターン形成方法を説明するための工程フロー図である。
【図６】 本発明の実施の形態３のレジストパターン形成方法を説明するための工程フロー図である。
【図７】 本発明の実施例１における第１のレジストパターンを示す平面図である。
【図８】 本発明の実施例２における第１のレジストパターンを示す平面図である。
【図９】 本発明の実施例３における第１のレジストパターンを示す平面図である。
【図１０】 本発明の実施例４における第１のレジストパターンを示す平面図である。
【図１１】 本発明の実施例１８〜２０における第２のレジストパターンを示す平面図である。
【図１２】 本発明の実施例２１〜２４における第２のレジストパターンを示す平面図である。
【図１３】 本発明の実施例２５における第２のレジストパターンを示す平面図である。
【符号の説明】
１、１１および２１ 第１のレジスト、１ａ、１１ａおよび２１ａ 第１のレジストパターン、２、１２および２２ 第２のレジスト ３ 半導体基板 ４、１４および２４ 架橋層。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor device using a material for fine patterning and a manufacturing method thereof in order to reduce a pattern separation size or a hole opening size when forming a resist pattern in a semiconductor process.
[0002]
[Prior art]
Along with the high integration of semiconductor devices, the wiring and isolation width required for the manufacturing process have become very fine. In general, a fine pattern is formed by a method in which a resist pattern is formed by a photolithography technique and various underlying thin films are etched using the formed resist pattern as a mask.
[0003]
Therefore, the photolithography technique is very important in forming a fine pattern. The photolithography technique is composed of resist coating, mask alignment, exposure, and development, and there is a limit to miniaturization due to restrictions on the exposure wavelength.
[0004]
Therefore, as a method for forming a fine resist pattern exceeding the limit of photolithography technology by conventional exposure, methods such as JP-A-6-250379 and JP-A-7-134422 have been proposed. The mutual diffusion of the resin components of the first resist and the second resist is utilized. However, a photoresist material that is soluble in an organic solvent that can dissolve the first resist is used as the second resist, and there is a problem that the first resist pattern is deformed.
[0005]
In addition, a processing method for removing the second resist includes a developer (an alkaline developer such as a tetramethylammonium hydrate aqueous solution or the like) that can expose the second resist, generate an acid, and dissolve the second resist. The second resist is dissolved and removed using xylene or the like. However, when the second resist is exposed, it may be solubilized by exposing the first resist which is the base. Since the solubilized first resist is soluble in a solution capable of dissolving the second resist, there is a high possibility that the first resist is dissolved when the second resist is dissolved and removed. The margin is small.
[0006]
In addition, when polyvinyl alcohol described in JP-A-6-250379 is used as the second resist, its effect is small, the pattern shape after processing is poor, and development is performed only with water. However, sufficient cleaning is not performed, and a development residue such as a stain is likely to remain on the pattern, which causes a pattern defect during etching in the next process.
[0007]
[Problems to be solved by the invention]
As described above, it has been difficult to form a fine resist pattern exceeding the wavelength limit by the conventional photolithography technique using exposure.
Further, although a technique that enables pattern formation exceeding the wavelength limit has been proposed, some problems remain and it is difficult to apply to actual semiconductor manufacturing.
The present invention has been made to solve such a problem, and for fine patterning for realizing fine separation resist pattern formation that enables formation of a pattern exceeding the wavelength limit in making the separation pattern and hole pattern finer. An object of the present invention is to provide a material, a method of manufacturing a semiconductor device using a finely divided resist pattern forming technique using the material, and a semiconductor device manufactured by the manufacturing method.
By the above manufacturing method, the development residue can be eliminated, the pattern shape can be improved, and the process margin can be expanded.
[0008]
[Means for Solving the Problems]
A first semiconductor device manufacturing method according to the present invention is provided on a semiconductor substrate. By the first resist that generates acid by light irradiation or heat treatment, Forming a first resist pattern on the first resist pattern; the above Forming a second resist that undergoes a crosslinking reaction with an acid; the above A step of forming a cross-linked layer at the second resist interface portion in contact with the first resist pattern by supplying acid; and dissolving the non-cross-linked portion of the second resist without dissolving the first resist pattern. A method for manufacturing a semiconductor device, comprising: a step of developing to form a second resist pattern; and a step of etching the semiconductor substrate using the second resist pattern as a mask, wherein the second resist material comprises: , Cross-linking agent and the above In the presence of acid the above Containing a resin that is crosslinked by a crosslinking agent; The solvent used for the second resist material and the solvent for developing the second resist are one or more kinds that dissolve the resin and the crosslinking agent and do not dissolve the first resist containing pure water. A solvent, the cross-linking agent is of a single polymerization degree, and is either a monomer, a dimer or a trimer, Furthermore, the resin has a molecular weight distribution with a dispersity (Mw / Mn) of 11 or less. And the weight average molecular weight is 100,000 or less. It is characterized by this.
[0013]
According to the present invention 2 The method for manufacturing a semiconductor device is that in the first method for manufacturing a semiconductor device, the degree of dispersion (Mw / Mn) of the resin is 1 to 3 and the weight average molecular weight is 50,000 or less.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a diagram showing a mask pattern for forming a finely separated resist pattern targeted by the present invention. Examples of the mask pattern are shown in (a) to (f). That is, (a) is a fine hole mask pattern 100, (b) is a fine square pattern 200, (c) is a fine space mask pattern 300, (d) is an isolated pattern 400, (e) is An isolated residual pattern 500, (f) shows an isolated residual pattern 600. 2 and 3 are process flow diagrams for illustrating the finely divided resist pattern forming method according to the first embodiment of the present invention.
[0018]
First, a method for forming a fine separation resist pattern according to this embodiment and a method for manufacturing a semiconductor device using the same will be described with reference to FIGS.
As shown in FIG. 2A, a first resist 1 having a mechanism for generating an acid therein is applied to a semiconductor substrate (semiconductor wafer) 3 by light irradiation or heat treatment (for example, a thickness of 0.7). ˜1.0 μm).
The first resist 1 is applied on a semiconductor substrate by spin coating or the like, and then pre-baked (heat treatment at 70 to 120 ° C. for about 1 minute) to evaporate the solvent in the first resist. Let
[0019]
Next, in order to form the first resist pattern, the sensitivity wavelength of the first resist used, such as g-line, i-line, Deep-UV, KrF excimer, ArF excimer, EB (electron beam) or X-ray, is used. Projection exposure is performed using a light source corresponding to the above and using a mask including a pattern as shown in FIG.
[0020]
The first resist used here is not particularly limited, and may be any resist that uses a mechanism that generates an acidic component inside the resist by heat treatment or irradiation with light, for example, KrF excimer, ArF. Any resist may be used as long as it generates acid upon irradiation with excimer, EB (electron beam), X-ray or the like, and either a positive type or a negative type resist may be used.
For example, examples of the first resist include a positive resist composed of a novolak resin and a naphthoquinonediazide-based photosensitizer.
Furthermore, as the first resist, a chemically amplified resist using a mechanism that generates an acid upon exposure can be applied. The resist is not particularly limited as long as it is a resist material that uses a reaction system that generates an acid upon exposure. Never happen.
[0021]
After the exposure of the first resist as described above, PEB (post-exposure heating) is performed as needed (for example, PEB temperature: 50 to 130 ° C.) to develop the resist resolution.
Next, it develops using about 0.05-3.0 wt% alkaline water bath liquid, such as TMAH (tetramethylammonium hydroxide). FIG. 2B shows the first resist pattern 1a thus formed.
Further, after the development processing, if necessary, for example, post-development baking may be performed at a baking temperature of 60 to 120 ° C. for about 60 to 90 seconds.
Since this heat treatment affects the subsequent mixing reaction, it is desirable to set the temperature appropriately in accordance with the first resist or the second resist material to be used.
The process described above is the same as the formation of a resist pattern by a general resist process, except that the first resist 1 that generates an acid is used.
[0022]
As described above, after forming the pattern 1a of FIG. 2B, as shown in FIG. 2C, the second resist material is crosslinked by the presence of an acid dissolved in a solvent that does not dissolve the first resist 1. Is applied to the first resist pattern 1 a on the semiconductor substrate 3.
The method of applying the second resist material is not particularly limited as long as it can be uniformly applied onto the first resist pattern 1a, and is applied by spraying or dipped in the second resist solution. It is also possible to apply by.
Next, after the application of the second resist 2, as shown in FIG. 2 (d), this is pre-baked (for example, at about 85 ° C. for about 60 seconds) to form the second resist layer 2. .
[0023]
Next, as shown in FIG. 2 (e), the semiconductor substrate 3 is heat-treated (60 to 130 ° C., hereinafter abbreviated as “mixing bake: MB”) to diffuse the acid from the first resist pattern 1a. Then, a crosslinking reaction is generated at the interface between the second resist 2 and the first resist pattern 1a. A crosslinked layer 4 that has undergone a crosslinking reaction so as to cover the first resist pattern 1 a with the MB is formed in the second resist 2.
The MB temperature / time in this case is 60 to 130 ° C./60 to 120 sec, and it may be set to an optimum condition depending on the type of resist material to be used and the required thickness of the reaction layer.
In addition, the thickness of the cross-linked layer can be controlled by adjusting the time for heating and cross-linking (MB time), which is a highly reactive control method.
[0024]
Next, as shown in FIG. 2F, the second resist 2 that has not been cross-linked is developed and peeled off without dissolving the first resist pattern using a developer. By the above processing, it becomes possible to obtain a resist pattern (second resist pattern 2a) in which the hole inner diameter or separation width is reduced or the area of the isolated pattern is enlarged.
[0025]
In the manufacturing method described above with reference to FIG. 2, after the second resist layer is formed on the first resist pattern, the first resist pattern 1a is transferred from the first resist pattern 1a to the second resist by an appropriate heat treatment. A method for generating an acid that diffuses an acid has been described.
As the second resist, an appropriate material having high reactivity is selected, and an appropriate heat treatment (for example, 85 ° C. to 150 ° C.) is performed, so that there is no exposure for acid generation in the first resist pattern. It is possible to obtain a resist pattern in which the interface between the resists causes a cross-linking reaction due to the diffusion of the acid present in the resist, and the hole inner diameter or separation width is reduced or the area of the isolated pattern is enlarged.
[0026]
Using the fine separation resist pattern 2a formed on the first resist pattern 1a as a mask as described above, various underlying thin films are etched to form fine spaces or fine holes in the underlying thin film, thereby manufacturing a semiconductor device. .
[0027]
Next, a method of generating and diffusing an acid by exposure instead of heat treatment or prior to heat treatment will be described.
FIG. 3 is a process flow diagram for explaining the fine resist pattern forming method in this case. First, FIGS. 3A and 3B are the same as FIGS. 2A and 2B, and thus description thereof is omitted.
[0028]
As shown in FIG. 3C, after forming the second resist layer, the entire surface of the semiconductor substrate is again exposed with the g-line or i-line of the Hg lamp to generate an acid in the first resist. As shown in FIG. 3D, a crosslinked layer 4 is formed at the interface of the second resist 2 in contact with the first resist pattern 1a.
The light source used for exposure at this time can be an Hg lamp, KrF excimer, ArF excimer, or the like depending on the photosensitive wavelength of the first resist, and is particularly limited as long as it can generate an acid by exposure. What is necessary is just to expose using the light source and exposure amount according to the photosensitive wavelength of the used 1st resist instead of what.
The exposure step for generating an acid component in the first resist pattern 1a may be performed when the applied first resist and second resist are relatively low in reactivity, or the required thickness of the crosslinked layer is relatively low. Although it is desirable to apply it when it is thick or when it is desired to selectively form a crosslinked layer, it is not particularly limited and may be used as appropriate.
[0029]
As described above, in the example of FIG. 3, exposure is performed after the application of the second resist 2 to generate an acid in the first resist pattern 1 a, and the first resist pattern 1 a is used as the second resist. Since the exposure is performed in a state covered with 2, the amount of acid generated in the first resist pattern 1a can be accurately controlled over a wide range by adjusting the exposure amount, so that the thickness of the crosslinked layer 4 can be accurately controlled. it can.
[0030]
As described above, using the formed fine separation resist pattern (second resist pattern 2a) as a mask, various underlying thin films are etched to form a fine space or a fine hole in the underlying thin film, thereby manufacturing a semiconductor device. Can do.
[0031]
In the above example, the method for forming the fine resist pattern 2a on the entire surface of the semiconductor substrate 3 has been described. Next, a method for selectively forming a fine resist pattern only in a desired region of the semiconductor substrate 3 will be described. FIG. 4 is a process flow diagram of the manufacturing method in this case.
[0032]
That is, as shown in FIG. 4, in addition to exposing the entire surface of the semiconductor substrate 3 on which the second resist is formed on the first resist pattern, it is also possible to selectively expose only the necessary predetermined portions. In this case, it is possible to distinguish between a region where the second resist is cross-linked at the interface with the first resist pattern and a region where the second resist is not cross-linked.
In this way, by using an appropriate light shielding plate (exposure mask) 5, the semiconductor substrate is selectively exposed to distinguish between the exposed portion and the unexposed portion, and the second resist pattern becomes the first resist pattern. In the boundary part, a region to be cross-linked and a region not cross-linked can be formed. Thereby, fine holes or fine spaces having different dimensions can be formed on the same semiconductor substrate.
[0033]
The steps of FIGS. 4A and 4B are the same as the steps of FIGS. 3A and 3B. As shown in FIG. 4C, after the second resist 2 layer is formed, a part of the semiconductor substrate 3 is shielded from light by the light shielding plate 5, and the selected region is exposed to light. Acid is generated in the resist pattern 1a. As a result, as shown in FIG. 4D, a crosslinked layer 4 is formed at the interface of the second resist 2 in contact with the first resist pattern 1a in the exposed portion.
[0034]
Next, the second resist material will be described.
As the second resist material, an unsaturated bond or a hydroxyl group-containing resin (crosslinkable resin) which is cross-linked by an acid, or a mixture of two or more types, or a cross-linking agent and an acid in the presence of the cross-linking agent What contains resin to be bridge | crosslinked is used as a solution melt | dissolved in the solvent, for example.
The resin cross-linked by the cross-linking agent may be the above cross-linkable resin, but is not limited thereto, and any resin that is cross-linked by the cross-linking agent in the presence of an acid may be used.
As a second resist forming method, the solution is formed by spin coating, dipping in the solution or spray coating.
When a resin mixture is used as the second resist, the material composition is not particularly limited as long as an optimal composition is set depending on the first resist material to be applied or the set reaction conditions. .
[0035]
That is, the material applied to the second resist is particularly limited as long as it is a material that is soluble in a solvent that does not dissolve the first resist pattern 1a and that causes a crosslinking reaction in the presence of an acid component. is not.
The second resist that causes a crosslinking reaction in the presence of an acid includes a case where the resist material itself is a crosslinkable compound. Further, the second resist that causes a crosslinking reaction in the presence of an acid is a resist material. And the case where a compound as a crosslinking agent and a crosslinking compound as a crosslinking agent are mixed.
[0036]
Examples of the resin include polyacrylic acid, polyvinyl acetal, polyvinyl pyrrolidone, unsaturated polyester, polyvinyl alcohol, polyethyleneimine, polymethyl methacrylate, styrene-maleic anhydride copolymer, acrylic resin, polyimide, polyvinylamine, polyallylamine, Oxazoline group-containing resin, urethane resin, phenol resin, cellulose resin, sulfonamide resin, maleic acid resin, vinyl resin, epoxy resin, silicone resin, unsaturated organopolysiloxane, unsaturated organopolysilsesquioxane, melamine resin, Urea resin, alkyd resin or sulfonamide, or a salt thereof is used.
These resins are not limited to those described above, and any resin can be used as long as it can be uniformly coated on a substrate with a reaction site that promotes a crosslinking reaction, that is, a polymer or oligomer having an unsaturated bond or a hydroxyl group.
The dry etching resistance can be improved by combining a silicone resin as the resin.
[0037]
The resin used for the second resist material may be used as one or a mixture of two or more of the above resins, and can be appropriately adjusted depending on the reaction amount with the underlying resist, reaction conditions, etc. The resin may be used in the form of a salt such as hydrochloride for the purpose of improving the solubility in a solvent.
In particular, when the crosslinking reaction under the acidic component of the resin does not occur or is low, a crosslinking agent can be further mixed with these resins.
[0038]
The cross-linking agent is capable of cross-linking resins by heat treatment or light irradiation in the presence of an acid to insolubilize the resin in an organic solvent. For example, guanidine, thiazole, thiuram, dithioicarbamate Organic accelerators, melamine derivatives, urea derivatives, benzoguanamines, glycolurils, isocyanates, polyfunctional epoxies, polyfunctional acrylic resins, polyfunctional urethanes, monomers of polyfunctional silicone resins or oligomers thereof, or two or more of them It is characterized by using a mixture. The crosslinking agent soluble in these organic solvents is not limited to the above, and any crosslinking agent can be used as long as it does not mix with or dissolve in the first resist and can cure the resist by supplying an acid.
[0039]
In addition, the solvent used for the second resist material and the solvent for peeling (developing) the second resist sufficiently dissolve the constituent resin and the crosslinking agent and do not dissolve the first resist. The above mixed solvent is used.
Solvents include pure water, alcohols, ketones, ethers, esters, halogenated hydrocarbons, benzenes, alkoxybenzenes, cyclic ketones, such as toluene, xylene, methoxybenzene, ethoxybenzene, benzene , Pyridine, cyclohexane, dioxane, methyl ethyl ketone, methyl isobutyl ketone, acetone, t-butyl acetate, n-butyl acetate, ethyl acetate, tetrahydrofuran, diethyl ether, isopropyl ether, methyl cellosolve, ethyl cellosolve, N-methylpyrrolidone, N, N '-Dimethylformamide, ethanol, methanol, isopropanol, butyl alcohol, ethylene glycol, ethylbenzene, diethylbenzene, n-butyl ether, n-hexane, n-heptane, Toxibenzene, ethoxybenzene, phenetole, veratrol, γ-butyrolactone, chloroform, and the like. These solvents can be used alone or in accordance with the solubility of the material used for the second resist. What is necessary is just to mix a solvent in the range which does not melt | dissolve a 1st resist pattern.
[0040]
In the present invention, it is important to control the crosslinking reaction between the first resist and the second resist and to control the thickness of the crosslinked layer formed on the first resist pattern.
The control of the crosslinking reaction can be optimized according to the reactivity between the first resist and the second resist to which the present invention is applied, the shape of the first resist pattern, the thickness of the required crosslinking reaction layer, and the like. desirable.
[0041]
Control of the crosslinking reaction between the first resist and the second resist includes a method by adjusting process conditions and a method by adjusting the composition of the second resist material.
As a process control method of the crosslinking reaction,
(1) adjusting the exposure amount to the first resist pattern;
(2) Adjust mixing bake (MB) temperature and processing time.
From the aspect of the material composition used for the second resist,
(3) Mix two or more types of suitable resins and adjust the mixing ratio.
(4) The resin is mixed with an appropriate crosslinking agent, and the mixing ratio is adjusted.
Such a method is effective.
[0042]
However, the control of these cross-linking reactions is not determined centrally,
(1) Reactivity with the first resist material to be applied,
(2) First resist pattern shape, film thickness,
(3) Required film thickness of the crosslinking agent layer,
(4) Usable exposure conditions or MB conditions,
(5) It is necessary to determine in consideration of various conditions such as coating conditions.
In particular, it has been found that the reactivity between the first resist and the second resist is affected by the composition of the first resist material. Therefore, when the present invention is actually applied, the above-mentioned is described. It is desirable to optimize the second resist material composition in consideration of factors.
Accordingly, the type of material used for the second resist and the composition ratio thereof are not particularly limited, and are optimized and used according to the type of material used, heat treatment conditions, and the like.
[0043]
Further, according to the present invention, as described above, the fine separation resist pattern is formed on the semiconductor substrate 3, but this may be formed on an insulating layer such as a silicon oxide film according to the manufacturing process of the semiconductor device. It may also be formed on a conductive layer such as a polysilicon film.
The present invention is not particularly limited to the base film, and can be applied in any case as long as it is on a substrate on which a resist pattern can be formed, and is formed on a substrate as necessary. is there.
[0044]
In the present invention, before forming the second resist film on the first resist pattern, the first resist pattern is heat-treated to control the solvent resistance of the second resist to the solvent and the developer. By doing so, the margin of the development conditions of the second resist is widened, and the shape of the obtained fine pattern or fine space can be improved. The heat treatment temperature of the first resist pattern may be equal to or lower than the thermal decomposition temperature of the resist to be used. In particular, the heat treatment temperature is preferably in a range of 60 ° C. to 150 ° C., for example, 30 seconds to 300 seconds on a hot plate.
[0045]
In the present invention, as the resin used for the second resist, the use of a resin having a molecular weight distribution of monodispersion or dispersity (Mw / Mn) of 11 or less means that the resist pattern is not observed without developing residue. This is preferable because the shrinking proceeds.
[0046]
In the present invention, it is preferable to use a resin having a molecular weight of 100,000 or less as the resin used for the second resist because the development of the resist pattern proceeds without observing development residues.
[0047]
In the present invention, as the crosslinking agent used for the second resist, use of a monomer or dimer having a single polymerization degree causes the crosslinking reaction with the resin accompanying heat treatment or light irradiation to proceed uniformly. preferable.
[0048]
Further, in the case where the cross-linking agent is a mixture composed of different degrees of polymerization, the reaction amount of the second resist can be adjusted by controlling the composition ratio, and the reduction of the resist pattern can be controlled.
[0049]
In the present invention, the number of cross-linking groups of the cross-linking agent is adjusted by adjusting the isomer ratio such as the composition ratio of positional isomers having different numbers of substituents contributing to the cross-linking reaction. In order to increase the crosslinking efficiency, it is preferable to use a polyfunctional crosslinking agent having many substituents that contribute to crosslinking.
[0050]
Furthermore, in the present invention, the following effects can be obtained by using a combination of the resin whose dispersity or molecular weight is adjusted as the second resist material and the cross-linking agent whose degree of single polymerization or the number of cross-linking groups is adjusted. Can do.
First, the solubility in the developer increases, which can contribute to shortening the development time and reducing or eliminating the development residue. This effect is greater as the resin has a lower degree of dispersion and a lower molecular weight, and in particular, the degree of dispersion ( A resin having a Mw / Mn) of 1 to 3 and a molecular weight of 50,000 or less is preferable. Further, the crosslink density of the crosslink layer is made uniform in the plane, and the pattern shape after development can be controlled. This effect is even greater when combined with a resin having a lower degree of dispersion and a lower molecular weight and a crosslinker having a lower degree of polymerization, especially a single degree of polymerization below the trimer.
In addition, the thickness of the crosslinked layer can be controlled by changing the crosslinking reactivity of the resin. The greater the molecular weight of the resin and the greater the number of reactive groups such as unsaturated groups and hydroxyl groups, the more the isomer ratio of the crosslinking agent. The larger the ratio of the cross-linking group polyfunctional, the greater the insolubility after the cross-linking reaction and the thicker the cross-linking layer.
In addition, process margins such as heat treatment conditions and development conditions can be expanded, and a non-crosslinked portion with respect to the developer can be obtained by combining a resin having a lower degree of dispersion and a lower molecular weight with a single low polymerization degree crosslinker. The process margin is further increased due to the increased solubility of.
[0051]
The semiconductor manufacturing apparatus of the present invention is manufactured by the above-described manufacturing method of each semiconductor device.
[0052]
Embodiment 2. FIG.
FIG. 5 is a process flow diagram for explaining the finely divided resist pattern forming method according to the second embodiment of the present invention. With reference to FIGS. 1 and 5, a method for forming a finely divided resist pattern according to the second embodiment and a method for manufacturing a semiconductor device using the same will be described.
[0053]
As shown in FIG. 5A, a first resist 11 containing a slight amount of acidic substance is applied to the semiconductor substrate 3. The first resist 11 is pre-baked (heat treatment at 60 to 150 ° C. for about 1 minute), and then is projected and exposed using a gg or i line of an Hg lamp and a mask that eats a pattern as shown in FIG. (It is omitted in FIG. 5). Then, if necessary, heat treatment is performed with PEB (10 to 150 ° C.) to improve the resolution of the resist, and then development is performed using an about 2.0% diluted water bath solution of TMAH (tetramethyl ammonium hydroxide).
[0054]
Thereafter, post-development baking may be performed as necessary. Since this heat treatment affects the subsequent mixing reaction, it is necessary to set the temperature appropriately. FIG. 5B shows the first resist pattern 11a formed in this way.
The process described above is the same as the formation of a resist pattern by a conventional resist process, except that a resist containing an acid is used.
[0055]
Next, after forming the resist pattern of FIG. 5B, as shown in FIG. 5C, a crosslinkable compound that crosslinks due to the presence of an acid is formed on the semiconductor substrate (wafer) 3 with the first resist pattern 11a. A second resist 12 dissolved in a solvent that does not dissolve is applied. As the solvent used here, the same material as that described in Embodiment Mode 1 is used.
Next, after the application of the second resist 12, it is pre-baked as necessary. Since this heat treatment affects the subsequent mixing reaction, it is desirable to set the temperature appropriately.
[0056]
Next, as shown in FIG. 5D, the semiconductor substrate 3 is heat-treated (60 to 150 ° C.), and the second resist 12 is supplied by supplying acid from some acidic substances contained in the first resist pattern 11a. A cross-linking reaction is caused in the vicinity of the interface with the first resist pattern 11a. As a result, a crosslinked layer 14 that has undergone a crosslinking reaction so as to cover the first resist pattern 11 a is formed in the second resist 12.
[0057]
Next, as shown in FIG. 5E, the second resist 12 that has not been cross-linked without developing the first resist pattern is developed and peeled off using a developer. By the above processing, it is possible to obtain the second resist pattern 12a having a reduced hole inner diameter or separation width.
[0058]
As described above, the first resist 11 in Embodiment 2 does not need to generate an acid by exposure, and is adjusted so that the first resist film 11 itself contains an acid. Is diffused to crosslink. The acid contained in the first resist is preferably a carboxylic acid-based low molecular acid or the like, but is not particularly limited as long as it can be mixed with the resist solution.
[0059]
Note that the first resist material and the second resist material reversed in the first embodiment can also be used in the second embodiment.
Further, the fine separation resist pattern 2a is formed on various semiconductor substrates, and using this as a mask, fine separation spaces or fine holes are formed on the semiconductor substrate. Same as 1.
[0060]
Embodiment 3 FIG.
FIG. 6 is a process flow diagram for explaining the finely divided resist pattern forming method according to the third embodiment of the present invention. A method for forming a finely divided resist pattern according to the third embodiment and a method for manufacturing a semiconductor device using the same will be described with reference to FIGS.
[0061]
First, as shown in FIG. 6A, a first resist 21 is applied to the semiconductor substrate 3. After pre-baking the first resist (heat treatment at 60 to 150 ° C. for about 1 minute), depending on the photosensitive wavelength of the first resist, for example, using the g-line or i-line of the Hg lamp, as shown in FIG. Projection exposure is performed using a mask including such a pattern (omitted in FIG. 6).
If necessary, heat treatment is performed with PEB (10 to 150 ° C.) to improve the resolution of the photoresist, and then development is performed using an about 2.0% diluted aqueous solution of TMAH (tetramethylammonium hydroxide). FIG. 6B shows the first resist pattern 21a formed in this way.
[0062]
Thereafter, post-development baking may be performed as necessary. Since this heat treatment affects the subsequent mixing reaction, it is necessary to set the temperature appropriately. The above process is the same as the formation of a resist pattern by a conventional resist process.
[0063]
After the pattern formation of FIG. 6B, as shown in FIG. 6C, the semiconductor substrate (wafer) 3 is immersed in an acidic solution. The processing method may be a normal paddle development method. Moreover, you may carry out by vaporization (spraying) of an acidic solution. In this case, the acidic solution may be either an organic acid or an inorganic acid. Specifically, for example, a low concentration of acetic acid is a suitable example.
In this step, the acid soaks in the vicinity of the interface of the first resist pattern 21a, and a thin layer containing the acid is formed. Thereafter, rinsing is performed using pure water as necessary.
[0064]
Thereafter, as shown in FIG. 6E, the second resist dissolved in a solvent that contains a crosslinkable compound that crosslinks in the presence of an acid and does not dissolve the first resist 21 on the first resist pattern 21a. A resist 22 is applied.
The second resist used here and the solvent used can be formed using the same materials as those described in Embodiment Mode 1.
Next, after the application of the second resist, the second resist 22 is pre-baked as necessary. Since this heat treatment affects the subsequent mixing reaction, it is set to an appropriate temperature.
[0065]
Next, as shown in FIG. 6F, the semiconductor substrate 3 is heat-treated (60 to 150 ° C.), mixed and baked, and the second resist 22 is formed by supplying acid from the first resist 21a. A crosslinking reaction is caused in the vicinity of the interface with the first resist pattern 21a. As a result, a crosslinked layer 24 that has undergone a crosslinking reaction so as to cover the first resist pattern 21 a is formed in the second resist 22.
[0066]
Next, as shown in FIG. 6G, the second resist 22 that has not been cross-linked without developing the first resist pattern is developed and removed using a developer. By the above processing, it is possible to obtain the second resist pattern 22a with the hole inner diameter or the separation width reduced.
[0067]
As described above, according to the third embodiment, it is not necessary to generate an acid in the first resist by the exposure process, and before forming the second resist on the first resist, A surface treatment with an acidic liquid is performed, and the acid is diffused by heat treatment to crosslink.
[0068]
In the third embodiment, examples of the first resist 21 include a positive resist composed of a novolak resin and a naphthoquinonediazide-based photosensitizer used in the first embodiment. Further, as the first resist, It is possible to apply a chemically amplified resist using a mechanism that generates an acid upon exposure, and any resist material that uses a reaction system that generates an acid upon exposure is not particularly limited. The other resist materials and second resist materials described in the first embodiment can be applied to the third embodiment.
[0069]
Further, the fine separation resist pattern 22a thus formed is formed on various semiconductor substrates, and using this as a mask, fine separation spaces or fine holes are formed on the semiconductor substrate to manufacture a semiconductor device. This is the same as in the first and second embodiments described above.
[0070]
【Example】
Example 1.
As the first resist, an i-line resist composed of novolak resin and naphthoquinone diazide and using 2-heptanone as a solvent was used to form a resist pattern.
That is, after dropping and spin-coating the resist on a Si wafer, pre-baking was performed at 80 ° C./60 seconds to evaporate the solvent in the resist to form a first resist with a film thickness of about 0.8 μm. Next, the i-line reduced projection exposure apparatus was used as the exposure apparatus, and the first resist was exposed using the mask as shown in FIG. 1 as the exposure mask. Next, PEB treatment is performed at 110 ° C./90 seconds, followed by development using an alkaline developer (manufactured by Tokyo Ohka Kogyo Co., Ltd., NMD3), and each resist pattern having a separation size as shown in FIG. Obtained.
[0071]
Example 2
A resist pattern was formed using an i-line resist composed of novolak resin and naphthoquinone diazide as the first resist and using ethyl lactate and propylene glycol monoethyl acetate as the solvent.
That is, the resist was formed on the Si wafer so as to have a film thickness of about 1.0 μm by dropping and spin coating. Next, pre-baking was performed at 85 ° C./70 seconds to dry the solvent in the resist. Subsequently, exposure was performed using a Nikon stepper and a mask as shown in FIG. Next, PEB treatment is performed at 115 ° C./90 seconds, followed by development using an alkaline developer (NMD3: manufactured by Tokyo Ohka Kogyo Co., Ltd.) to obtain each resist pattern having a separation size as shown in FIG. It was.
[0072]
Example 3
As the first resist, a chemically amplified excimer resist (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used to form a resist pattern.
That is, the resist was formed on the Si wafer so as to have a film thickness of about 0.85 μm by dropping and spin coating. Next, pre-baking was performed at 80 ° C./70 seconds to dry the solvent in the resist. Subsequently, exposure was performed using a mask as shown in FIG. 1 using a KrF excimer reduction projection exposure apparatus. Next, PEB treatment is performed at 110 ° C./60 seconds, followed by development using an alkali developer (NMD-W: manufactured by Tokyo Ohka Kogyo Co., Ltd.), and each resist pattern having a separation size as shown in FIG. Got.
[0073]
Example 4
A resist pattern was formed using a chemically amplified resist composed of t-Boc polyhydroxystyrene and an acid generator as the first resist.
That is, the resist was formed on the Si wafer so as to have a film thickness of about 0.60 μm by dropping and spin coating. Next, baking was performed at 115 ° C./120 seconds to dry the solvent in the resist. Subsequently, Espacer ESP-100 (manufactured by Showa Denko) was spin-coated on the resist as an antistatic film in the same manner, and then baked at 90 ° C./90 seconds. Next, using an EB drawing apparatus, 16.4 μC / cm ² Draw with. Next, after PEB is performed at 80 ° C./120 seconds, the antistatic film is removed using pure water, and then the resist pattern is developed using a TMAH alkaline developer (NMD-W: manufactured by Tokyo Ohka Kogyo Co., Ltd.). As shown in FIG. 10, each EB resist pattern of about 0.28 μm was obtained.
[0074]
Next, examples relating to a fine patterning material used as the second resist material will be described.
[0075]
Example 5 FIG.
As a second resist material, use a 1 L measuring flask, add 855 g of pure water and 95 g of isopropanol to 50 g of polyvinyl acetal resin having an average polymerization amount of 10,000, 30,000, 100,000, and 300,000, and stir and mix at room temperature for 6 hours. A 5 wt% solution of polyvinyl acetal resin was obtained.
[0076]
Example 6
Using a 1 L volumetric flask as the second resist material Child 950 g of pure water was added to 50 g of polyvinyl alcohol resin having an amount of about 30,000 and dispersity of about 2, 5, 10, and 30, and stirred and mixed at room temperature for 6 hours to obtain a 5 wt% solution of polyvinyl alcohol resin.
[0077]
Example 7
As a second resist material, a 1 L stopper bottle was used, 475 g of xylene was added to 25 g of polyvinylmethylsilsesquioxane, and mixed and dissolved overnight at room temperature using a wave rotary to obtain a 5 wt% solution of polyvinylmethylsilsesquioxane.
[0078]
Example 8 FIG.
As a second resist material, using a 1 L measuring flask, 100 g of methoxymethylene melamine and 900 g of isopropanol were stirred and mixed at room temperature for 6 hours to obtain an about 10 wt% methoxymethylene melamine solution.
[0079]
Example 9
Using a 1 L volumetric flask as a second resist material, 1,3-di (N-methoxymethyl) -2-imidazolidinone, 1,3-di (N-methoxymethyl) -4-hydroxy-2- The mixing ratio of the regioisomers of imidazolidinone, 1,3-di (N-methoxymethyl) -4,5-dihydroxy-2-imidazolidinone is 7: 2: 1, 1: 8: 1, 1: To a crosslinking agent different from 3: 6, 900 g of isopropanol was stirred and mixed at room temperature for 8 hours to obtain about 10 wt% solutions respectively.
[0080]
Example 10
Using a 1 L volumetric flask as a second resist material, 2-imidazolidinone 100 g, 1,3-di (N-methoxymethyl) -2-imidazolidinone 100 g, 1,3-di (N-methoxymethyl) ) In 100 g of 4-hydroxy-2-imidazolidinone and 1,3-di (N-methoxymethyl) -4,5-dihydroxy-2-imidazolidinone, 900 g of isopropanol was stirred at room temperature for 8 hours. Each was mixed to obtain about 10 wt% solution.
[0081]
Example 11
As a second resist material, using a 1 L measuring flask, 100 g of a monomer having a basic structure of 1,3-di (N-methoxymethyl) -4,5-dihydroxy-2-imidazolidinone, 100 g of a dimer, In 100 g of the trimer and 100 g of the oligomer, 900 g of isopropanol was stirred and mixed at room temperature for 8 hours, respectively, thereby obtaining about 10 wt% solutions.
[0082]
Example 12 FIG.
As a second resist material, a 1 L volumetric flask is used, and a polymer constituting an oligomer having a basic structure of 1,3-di (N-methoxymethyl) -4,5-dihydroxy-2-imidazolidinone is mixed. 100 g each using a crosslinking agent with a ratio of monomer: dimer: trimer: tetramer or higher = 6: 3: 1: 1, 1: 3: 4: 2, 0: 2: 3: 5 Each was stirred and mixed with 900 g of isopropanol at room temperature for 8 hours to obtain about 10 wt% solutions respectively.
[0083]
Example 13
As a second resist material, 160 g of the polyvinyl acetal solution obtained in Example 5 and 20 g of the methoxymethylol melamine solution obtained in Example 8 and 20 g of isopropanol were stirred and mixed at room temperature for 6 hours to obtain a mixed solution of a resin and a crosslinking agent. It was.
[0084]
Example 14
As a second resist material, 180 g of the polyvinyl alcohol solution obtained in Example 6 and 20 g of each imidazolidinone solution obtained in Example 9 were stirred and mixed at room temperature for 8 hours to obtain a mixed solution of a resin and a crosslinking agent. .
[0085]
Example 15.
As a second resist material, 180 g of the polyvinylmethylsilsesquioxane solution obtained in Example 7 and 20 g of each imidazolidinone solution obtained in Example 10 were mixed at room temperature for 6 hours.
[0086]
Example 16
As a second resist, 20 g of each imidazolidinone solution obtained in Example 11 was mixed with 100 g of the polyvinyl acetal resin solution having a polymerization average molecular weight of 30,000 obtained in Example 5, and at room temperature, 6 The mixture was stirred and mixed for a time to obtain a polyvinyl acetal resin solution.
[0087]
Example 17.
As a second resist, 20 g of each imidazolidinone solution obtained in Example 12 was mixed with 100 g of the polyvinyl acetal resin solution having a polymerization average molecular weight of 30,000 obtained in Example 5, and 6% at room temperature. The mixture was stirred and mixed for a time to obtain a polyvinyl acetal resin solution.
[0088]
Example 18
The second resist material obtained in Example 13 was dropped on the Si wafer on which the first resist pattern obtained in Example 2 was formed and spin-coated, followed by prebaking at 90 ° C./70 seconds. 2 resist films were formed. Next, mixing baking (MB) was performed at 115 ° C./90 seconds to advance the crosslinking reaction. Next, rinsing is performed with pure water, the non-crosslinked layer is developed and peeled off, and then post-baking is performed at 100 ° C./90 seconds, whereby a second resist is formed on the first resist pattern as shown in FIG. A crosslinked layer was formed.
In this case, from Table 1 showing the relationship between the weight average molecular weight of the resin and the resist pattern size in this example, the resist pattern is reduced because the insolubility of the crosslinked layer increases as the polymerization average molecular weight of the polyvinyl acetal resin increases. However, in the case of a resin having a weight average molecular weight exceeding about 100,000, a development residue is observed, which is a problem. In the case of a resin having a low weight average molecular weight (10,000, 30,000), a pattern with a small taper was obtained. For measurement of the taper angle, the pattern (f) in FIG. 1 was used.
[0089]
[Table 1]

[0090]
Example 19.
The resin obtained in Example 14 was dropped as a second resist material onto the Si wafer on which the first resist pattern obtained in Example 1 was formed and spin-coated, and then pre-baked at 90 ° C./70 seconds. A second resist film was formed.
Next, mixing baking (MB) was performed at 135 ° C./70 seconds to advance the crosslinking reaction. Next, development is performed using a pure aqueous solution containing 10% isopropanol, and the non-crosslinked layer is developed and peeled off, followed by post-baking at 120 ° C./90 seconds, as shown in FIG. A second resist cross-linked layer was formed on the hole pattern.
Thus, from Table 2 showing the relationship between the degree of dispersion of the resin and the resist pattern size in this example, the degree of dispersion of the resin having substantially the same weight average molecular weight affects the residue after development. understood.
[0091]
[Table 2]

[0092]
Further, the taper angle of the resist line on which the crosslinked layer is formed shows a value closer to the initial angle for the resin having a lower degree of dispersion. For measurement of the taper angle, the pattern (f) in FIG. 1 was used.
Further, as the cross-linking agent having a larger number of functional groups (cross-linking groups) contributing to the cross-linking reaction is used, the reduction rate of the resist pattern is higher.
[0093]
Example 20.
The polyvinylmethylsilsesquioxane resin solution obtained in Example 15 was used as the second resist on the Si wafer on which the first resist pattern obtained in Example 2 was formed.
After the second resist material was dropped and spin-coated, prebaking was performed at 80 ° C./70 seconds to form a second resist film.
Next, mixing baking (MB) was performed under three conditions of 100 ° C./90 seconds, 110 ° C./90 seconds, and 120 ° C./90 seconds to perform a crosslinking reaction. Next, development is performed using hexane, and the non-crosslinked layer is developed and peeled off, followed by post-baking at 90 ° C./90 seconds, thereby forming the second resist pattern on the first resist pattern as shown in FIG. A resist cross-linked layer was formed.
As a result, the inner diameter of the 0.4 μm-sized hole pattern formed in Example 2 and the size of the space in the line pattern and the isolated remaining pattern were reduced as shown in Table 3 in the resist pattern after forming the crosslinked layer. The reduction amount increases as the MB temperature increases.
[0094]
[Table 3]

[0095]
From this, it is understood that the crosslinking reaction can be accurately controlled by controlling the temperature of MB.
[0096]
Example 21.
After the Si wafer on which the first resist pattern obtained in Example 3 was formed was cured at 110 ° C., the polyvinyl acetal solution obtained in Example 16 was used as the second resist on the wafer.
After the second resist material was dropped and spin-coated, prebaking was performed at 85 ° C./70 seconds to form a second resist film.
Next, mixing baking (MB) was performed at 65 ° C./70 seconds + 100 ° C./90 seconds to perform a crosslinking reaction. Next, development is performed using pure water, and the non-crosslinked layer is developed and peeled off, followed by post-baking at 90 ° C./90 seconds, whereby the second resist layer is formed on the first resist pattern as shown in FIG. A resist cross-linked layer was formed.
As a result, the inner diameter of the hole pattern having a size of about 0.27 μm formed in Example 3 is clearly reduced from Table 4 showing the relationship between the degree of polymerization of the crosslinking agent and the resist pattern in this example, The amount of reduction decreases with increasing degree of polymerization.
[0097]
[Table 4]

[0098]
This shows that the cross-linking reaction can be controlled with high accuracy by using a single polymer of the cross-linking agent.
[0099]
Example 22
The polyvinyl acetal solution obtained in Example 17 was used as the second resist on the Si wafer on which the first resist pattern obtained in Example 4 was formed.
After the second resist material was dropped and spin-coated, prebaking was performed at 85 ° C./70 seconds to form a second resist film.
Next, mixing baking (MB) was performed at 70 ° C./70 seconds + 110 ° C./90 seconds to perform a crosslinking reaction. Next, development is performed using pure water, and the non-crosslinked layer is developed and peeled off, followed by post-baking at 85 ° C./90 seconds, so that the second resist is formed on the first resist pattern as shown in FIG. A resist cross-linked layer was formed.
As a result, from Table 5 showing the relationship between the polymerization degree distribution of the crosslinking agent and the resist pattern in this example, the inner diameter of the hole pattern having a size of about 0.28 μm formed in Example 4 was reduced, and the reduction It can be seen that the amount is large because the more the crosslinking agent composition has a low degree of polymerization, the more substituents involved in crosslinking.
[0100]
[Table 5]

[0101]
This shows that the crosslinking reaction can be controlled by the difference in the mixing ratio of the crosslinking agents having different polymerization degrees.
[0102]
Example 23.
The Si wafer on which the first resist pattern obtained in Example 3 was formed was pretreated by curing at 115 ° C. for 90 seconds, and then the 1,3-di (N— Methoxymethyl) -4-hydroxy-2-imidazolidinone-containing polyvinylmethylsilsesquioxane solution in which NMP was added to 10%, 1,3-di (N-methoxymethyl) obtained in Example 16 A solution in which isopropanol was dropped to a total of 20% in a polyvinyl acetal resin solution containing a monomer of -4,5-dihydroxy-2-imidazolidinone was used as the second resist.
After the second resist material was dropped and spin-coated, prebaking was performed at 80 ° C./70 seconds to form a second resist film.
Next, mixing baking (MB) was performed at 85 ° C./70 seconds + 110 ° C./90 seconds to perform a crosslinking reaction. Next, the polyvinylmethylsilsesquioxane resin film is developed with a xylene solution containing 10% NMP, and the polyvinyl acetal resin film is developed with pure water containing 20% isopropanol, and the non-crosslinked layer is developed and peeled off. By subsequently performing post-baking at 110 ° C./90 seconds, a second resist cross-linked layer was formed on the first resist pattern as shown in FIG.
As a result, as clearly shown in Table 6 showing the effect of the pretreatment in this example, the inner diameter of the hole pattern of about 0.27 μm size formed in Example 3 is reduced, but the reduction amount is the first. When the pre-treatment (heat treatment) of the first resist pattern was not performed, sagging or dissolution of the underlying first resist occurred when the second resist was applied, which had an adverse effect.
[0103]
[Table 6]

[0104]
For this reason, since the first resist pattern is heat-treated in advance, the type and mixing ratio of the solvent that uses the solvent and developer of the second resist to some extent can be widened, so that the selection of the constituent resin is expanded.
[0105]
Example 24.
1,6-di (N-methoxymethyl) -4,5-dihydroxy-2-imidazolidinone obtained in Example 11 was added to 180 g of a polyvinyl alcohol solution having a weight average molecular weight of about 30,000 and a dispersity of 2 in Example 6. 20 g of the monomer solution was mixed and stirred at room temperature for 6 hours to obtain a mixed solution of resin and crosslinking agent, which was used as the second resist. A second resist material is dropped and spin coated on the Si wafer on which the first resist pattern obtained in Example 3 is formed, and then prebaked at 90 ° C./70 seconds to form a second resist film. did.
Next, mixing baking (MB) was performed at 90 ° C./90 seconds, 100 ° C./90 seconds, 110 ° C./90 seconds, and 120 ° C./90 seconds to perform a crosslinking reaction. Next, development is performed using pure water for 60 seconds, 90 seconds, 120 seconds, and 180 seconds, the non-crosslinked layer is developed and peeled, and then post-baked at 115 ° C./90 seconds, as shown in FIG. Thus, the 2nd resist bridge | crosslinking layer was formed on the 1st resist pattern.
As a result, as clearly shown in Table 7 showing the effect of the process margin in this example, the inner diameter of the hole pattern of about 0.27 μm size formed in Example 3 is reduced, but the dispersion is relatively low and relatively low. By using a low molecular weight resin and a single low polymerization cross-linking agent, the margin of MB temperature and development time was expanded.
[0106]
[Table 7]

[0107]
As a comparison, a cross-linking agent was used when polyvinyl alcohol having a dispersity of 10 and a weight average molecular weight of 300,000 was used, and an oligomer of 1,3-di (N-methoxymethyl) -4,5-dihydroxy-2-imidazolidinone. The case of using was also described. When polyvinyl alcohol having a weight average molecular weight of 300,000 or an oligomer is used as a cross-linking agent, a development residue is observed, and depending on conditions, a hole is not opened after development and a measurement cannot be performed. . In addition, there is a development residue in a portion surrounded by a thick frame in Table 7.
From this, the process margin can be broadened to some extent by changing the molecular weight, dispersion degree and polymerization degree of the second resist material.
[0108]
Example 25.
The first resist pattern obtained in Example 2 was formed on the Si wafer on which the oxide film was formed, and the first resist pattern as shown in FIG. 13 was formed.
Next, after dropping the second resist material obtained in Example 13 and spin coating, pre-baking at 80 ° C./70 seconds, mixing baking (MB) at 110 ° C./70 seconds, and crosslinking reaction Made progress. Next, development is performed using pure water, and the non-crosslinked layer is developed and peeled off, followed by post-baking at 105 ° C./90 seconds to form a second resist crosslinked layer on the first resist hole pattern. did.
Furthermore, the underlying oxide film was etched using an etching apparatus, and the pattern shape after etching was observed.
Further, as a comparative example, a wafer (only the resist in the table) on which the first resist pattern shown in FIG. As a result, as shown in Table 8, when the present invention was applied, the separation width was reduced.
[0109]
[Table 8]

[0110]
As described above, in the present invention, in the resist separation pattern and hole pattern miniaturization, a fine separation resist pattern forming material capable of forming a pattern exceeding the wavelength limit and the formation of a fine pattern using the same. A method is obtained.
As a result, the hole diameter of the hole resist pattern can be reduced as compared with the conventional one, and the separation width of the space resist pattern can be reduced as compared with the conventional one.
Further, by using the finely separated resist pattern thus formed as a mask, finely separated spaces or holes can be formed on the semiconductor substrate.
In addition, a semiconductor device having finely separated spaces or holes can be obtained by such a manufacturing method.
[0111]
【The invention's effect】
The present invention of According to the semiconductor device manufacturing method Current There are effects that the image residue can be eliminated, the pattern shape can be improved, and the process margin can be expanded.
[Brief description of the drawings]
FIG. 1 is a mask pattern diagram used in an embodiment of the present invention.
FIG. 2 is a process flow diagram for explaining a resist pattern forming method according to the first embodiment of the present invention.
FIG. 3 is a process flow diagram for explaining the resist pattern forming method according to the first embodiment of the present invention;
FIG. 4 is a process flow diagram for explaining a resist pattern forming method according to the first embodiment of the present invention.
FIG. 5 is a process flow diagram for explaining a resist pattern forming method according to a second embodiment of the present invention.
FIG. 6 is a process flow diagram for explaining a resist pattern forming method according to a third embodiment of the present invention.
FIG. 7 is a plan view showing a first resist pattern in Example 1 of the present invention.
FIG. 8 is a plan view showing a first resist pattern in Example 2 of the present invention.
FIG. 9 is a plan view showing a first resist pattern in Example 3 of the present invention.
FIG. 10 is a plan view showing a first resist pattern in Example 4 of the present invention.
FIG. 11 is a plan view showing a second resist pattern in Examples 18 to 20 of the present invention.
FIG. 12 is a plan view showing a second resist pattern in Examples 21 to 24 of the present invention.
FIG. 13 is a plan view showing a second resist pattern in Example 25 of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 11 and 21 1st resist, 1a, 11a and 21a 1st resist pattern, 2, 12 and 22 2nd resist 3 Semiconductor substrate 4, 14, and 24 Crosslinked layer.

Claims (2)

On a semiconductor substrate, a first resist which generates an acid by light irradiation or heat treatment, and forming a first resist pattern, a second causing a crosslinking reaction by the acid in the first resist pattern on forming a resist, by the supply of the acid above and forming a crosslinked layer on the second resist surface portion in contact with the first resist pattern, the second not dissolve the first resist pattern A method for manufacturing a semiconductor device, comprising: a step of dissolving and developing a non-crosslinked portion of a resist to form a second resist pattern; and a step of etching the semiconductor substrate using the second resist pattern as a mask. ,
The second resist material,
Crosslinking agent and contains a resin that is crosslinked by the crosslinking agent in the presence of the acid,
The solvent used for the second resist material and the solvent for developing the second resist are:
One or more solvents that dissolve the resin and the crosslinking agent and do not dissolve the first resist containing pure water;
The cross-linking agent has a single polymerization degree and is either a monomer, a dimer, or a trimer.
Further the resin, a method of manufacturing a semiconductor device have a dispersity (Mw / Mn) 11 following molecular weight distribution, wherein the weight average molecular weight is 100,000 or less. 2. The method of manufacturing a semiconductor device according to claim 1, wherein the degree of dispersion (Mw / Mn) of the resin is 1 to 3 and the weight average molecular weight is 50,000 or less.

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