JP4461516B2 - Removal method of heat-resistant polymer protective film - Google Patents

Description

【０００８】
【発明の実施の形態】
ポリベンゾオキサゾール膜等の耐熱性高分子保護膜を剥離するためのドライエッチング処理は、半導体装置上のポリベンゾオキサゾール膜をある程度の膜厚まで削る目的で行う。ドライエッチング処理には酸素プラズマを使用する処理が好ましく、この場合は基板上の有機膜や有機溶剤のみをエッチングするので、無機膜である基板は影響を受けない。フッ素や塩素のラジカルを利用した反応性ガスによるドライエッチング処理の場合、Ｓｉ、ＳｉＯ₂、Ｓｉ₃Ｎ₄、Ａｌ等の基板がエッチングされてしまうので好ましくない。酸素プラズマによるドライエッチングは、高出力で行えばより短時間での有機物の除去が可能である。またエッチング装置槽内の温度は高い程好ましく、窒素や窒素と水素の混合ガスによるプレヒートを行えば、より短時間での除去が可能となる。
【０００９】
有機溶剤への浸漬処理は、ドライエッチング処理後に半導体装置上に残存するポリベンゾオキサゾール膜を完全に除去する目的で行う。ポリベンゾオキサゾール膜を除去するための溶解力の強い溶剤としては、パッケージ不良解析等に用いられる発煙硝酸、ハロゲン系溶剤、フェノールを含有している溶剤やフッ化水素の水溶液であるフッ酸等が挙げられるが、これらの材料は環境問題や人体への有害性等の問題が懸念される。そこで、より安全性の高い溶剤を使用した方が好ましいと考え、種々の溶剤を検討した結果、ジメチルスルホキシドとモノエタノールアミンの混合溶剤がポリベンゾオキサゾール膜等の溶解に優れることを見出した。更にモノエタノールアミンの含有量が多いものが好ましい。これは強いアルカリ性を有するモノエタノールアミンがオキサゾール環を分解して溶解するメカニズムを有しているためであると考えられる。この混合有機溶剤は加熱して使用することで、ポリベンゾオキサゾール膜等の除去をより短時間で行うことが出来る。更に好ましくは半導体装置の量産工場で広く使用されている、複数の洗浄槽および蒸気洗浄装置を備えたウエハ洗浄装置を利用することにより、非常に少ないパーティクルレベルを達成することが可能である。
【００１０】
ジメチルスルホキシドとモノエタノールアミンの混合割合は重量比で３：９７から９０：１０であり、好ましくは４：９６から５０：５０である。ジメチルスルホキシドの割合が３未満になると取り扱い性が少し悪くなり、９０を越えると溶解の時間が長くなるという問題が起こる。
【００１１】
本発明では酸素プラズマによるドライエッチング処理とジメチルスルホキシドとモノエタノールアミンからなる混合有機溶剤による浸漬処理を組み合わせる事により、ポリベンゾオキサゾール膜を除去することが出来、パーティクルを非常に少ないレベルまで低減することが可能である。ドライエッチング処理のみの場合、高温・高出力での処理により短時間での除去が可能である反面、除去された膜の有機物が槽内に残存していることがあり、ウエハ基板上に再付着する問題が懸念され好ましくない。一方、混合有機溶剤の浸漬による処理のみの場合は、膜を完全に溶解除去するまで長時間を要するばかりでなく、浸漬槽内の有機溶剤の汚染が著しくなるといった不具合が生じる。特に半導体装置の量産品に対してウエハ洗浄装置を使用する場合には、有機溶剤の汚染が早くなり溶解力が低下するため好ましくない。本発明においてはドライエッチング処理により短時間で膜厚を減少させた後、ジメチルスルホキシドとモノエタノールアミンからなる混合有機溶剤による浸漬処理を組み合わせる事により、効率よく、洗浄装置槽内の有機溶剤を著しく汚染させずに膜を除去することが出来、パーティクルを非常に少ないレベルまで低減することを特徴とするものである。
【００１２】
【実施例】
以下、実施例により本発明を具体的に説明する。
《実施例１》
＊ ポリベンゾオキサゾール前駆体の作成
テレフタル酸１３２．８ｇ（０．８モル）、イソフタル酸３３．２ｇ（０．２モル）と１−ヒドロキシ−１，２，３−ベンゾトリアゾール２７０．３ｇ（２モル）とを反応させて得られたジカルボン酸誘導体３６０．４ｇ（０．９モル）とヘキサフルオロ−２，２−ビス（３−アミノ−４−ヒドロキシフェニル）プロパン３６６．３ｇ（１．０モル）とを温度計、攪拌機、原料投入口、乾燥窒素ガス導入管を備えた４つ口のセパラブルフラスコに入れ、Ｎ−メチル−２−ピロリドン３０００ｇを加えて溶解させた。その後オイルバスを用いて７５℃にて１２時間反応させた。
【００１３】
次にＮ−メチル−２−ピロリドン５００ｇに溶解させた５−ノルボルネン−２，３−ジカルボン酸無水物３２．８ｇ（０．２モル）を加え、更に１２時間攪拌して反応を終了した。反応混合物をろ過した後、水／メタノール＝３／１の混合溶液中に投入して沈殿物を濾集し、水で十分ろ過した後、真空下で乾燥し、一般式（１）で表され、Ｘが下記式Ｘ−１、Ｙが下記式Ｙ−１及びＹ−２、Ｅが下記式Ｅ−１であるポリアミド（Ａ−1）を得た。
【化２】

【００１４】
＊ポジ型感光性樹脂組成物の作製
合成したポリアミド（Ａ−1）１００ｇ、下記式の構造を有するジアゾキノン（Ｑ−１）２５ｇをＮ−メチル−２−ピロリドン２００ｇに溶解し、３時間攪拌した。その後攪拌を止めて室温で放置し、３時間後に目視により外観の観察を行ったところ、気泡は見られなかった。その後、０．２μｍのテフロンフィルターで濾過し感光性樹脂組成物を得た。
【化３】

【００１５】
＊ポリベンゾオキサゾール硬化膜の作成
前記方法により合成したポリベンゾオキサゾール前駆体を含有するポジ型感光性樹脂組成物を用いて、シリコンウェハー上にスピンコーターで塗布した後、ホットプレートにて１２０℃で４分間乾燥し、膜厚約１１μｍの塗膜を得た。この塗膜にｉ線ステッパー露光機ＮＳＲ−２２０５ｉ１２Ｃ（ニコン（株）製）によりレチクルを通して５００ｍＪ／ｃｍ²の露光量で露光を行い、２．３８％のテトラメチルヒドロキシド水溶液に１００秒浸漬することによって露光部を溶解除去した後、純水で３０秒間リンスし、パターン形成を行った。このウエハをオーブン中で１５０℃で３０分、３２０℃で３０分加熱してポリベンゾオキサゾール閉環反応を行い、最終膜厚が約８μｍのポリベンゾオキサゾ―ル硬化膜を得た。
【００１６】
＊ポリベンゾオキサゾール硬化膜の除去
前記のポリベンゾオキサゾール硬化膜を形成したウエハをエッチング装置ＯＰＭ−ＥＭ１０００（東京応化工業（株）製）を用いて、窒素と水素の混合ガスと酸素を用いて槽内温度を２００℃まで昇温させた後、１０００Ｗで３分間の酸素プラズマ処理を行い、膜厚を０．２μｍまで減少させた。
【００１７】
続いてカイジョー製のウエットステーションにて有機溶剤による洗浄処理を行った。ウエハーフローのステップは、１槽目で組成がジメチルスルホキシド／モノエタノールアミン＝４／６である混合有機溶剤（以下剥離液という）を使用して１００℃・３０分間の処理を行い、２槽目で１槽目と同じ剥離液で１００℃・３０分間の処理を行い、３槽目でＮ−メチル−２−ピロリドンで常温１０分間のリンス処理を行い、４槽目で純水で１００℃・１分間の処理を行い、５槽目で純水で常温３分間の処理を行い、６槽目でイソプロピルアルコールのベーパー乾燥を４分間行い、最後にスピンドライを行うという工程であり、前記の酸素プラズマ処理によって膜厚を減少させたポリベンゾオキサゾール硬化膜をウエットステーションにて処理した。
【００１８】
＊ポリベンゾオキサゾール硬化膜の除去後の評価
剥離液への浸漬処理後のウエハについて、レーザ表面検査装置ＬＳ−５０００（日立電子エンジニアリング（株）製）を用いて粒径が１μｍ以上のパーティクル数を計測した結果２１であった。
【００１９】
《実施例２》
実施例１におけるポリベンゾオキサゾール膜をポリイミド膜に替えた他は実施例１と同様の評価を行った。以下にポリイミド前駆体及び硬化膜の作成方法を記す。
【００２０】
＊ポリイミド前駆体の作成
温度計、攪拌機、原料仕込口及び乾燥窒素ガス導入口を備えた四ツ口セパラブルフラスコに４，４’−ジアミノジフェニルエーテル１９０．２ｇ（０．９５モル）、１，３−ビス（３−アミノプロピル）−１，１，３，３−テトラメチルジシロキサン１２．４ｇ（０．０５モル）をとり、これに無水のＮ−メチル−２−ピロリドンを全仕込原料中の固形分割合が１５重量％になるだけの量を加えて溶解した。次いで０〜５０℃の水溶中にフラスコを浸漬し、発熱を抑制しながら、精製したピロメリット酸二無水物２１８．１ｇ（１モル）を投入した。テトラカルボン酸二無水物が溶解した後、系の温度を２０℃に保ち、１０時間反応を続けた。尚乾燥窒素ガスは反応の準備段階より生成物の取り出しまでの全行程にわたり流しておいた。得られた生成物は淡黄色の粘調な溶液であり、Ｎ−メチル−２−ピロリドン０．５重量％溶液の固有粘度は１．１（３０℃）であった。
【００２１】
＊ポリイミド硬化膜の作成
合成したポリイミド前駆体をシリコンウエハ上にスピンコーターで塗布した後、ホットプレートにて１４５℃で１分間乾燥し、膜厚約１１μｍの塗膜を得た。この塗膜にポジ型フォトレジストＯＦＰＲ−８００（東京応化工業（株）製）を用いてスピンコーターで塗布した後、１００℃で１分間乾燥し、さらにレチクルを通して２００ｍＪ／ｃｍ²の紫外線を照射して露光を行い、次いで２．３８％のテトラメチルヒドロキシド水溶液に６０秒間浸漬することによって露光部を溶解除去した後、純水で３０秒間リンスし、パターン形成を行った。その後酢酸ブチルに１分間浸漬することによりレジストを剥離した。このウエハをオーブン中で１５０℃で３０分、２３０℃で３０分、３５０℃で３０分加熱してポリイミド閉環反応を行い、最終膜厚が約６μｍのポリイミド硬化膜を得た。
【００２２】
《実施例３》
実施例１においてポリベンゾオキサゾール膜の硬化温度を３５０℃に替えた他は実施例１と同様の評価を行った。
《実施例４》
実施例１において、ウエットステーションで使用した１槽目および２槽目の剥離液を組成がジメチルスルホキシド／モノエタノールアミン＝６／４であるものに替え、更に剥離液の加熱温度を１２０℃に替えた他は実施例１と同様の評価を行った。
《実施例５》
実施例１において、ウエットステーションで使用した１槽目および２槽目の剥離液を組成がジメチルスルホキシド／モノエタノールアミン＝４／９６である剥離液を使用した以外は実施例１と同様の処理を行い、実施例１と同様の評価を行った。
【００２３】
《比較例１》
実施例１において酸素プラズマ処理工程を行わずにポリベンゾオキサゾール硬化膜の除去を試みた。
《比較例２》
実施例１において、本発明による剥離液の処理を行わずに、酸素プラズマ処理のみでポリベンゾオキサゾール硬化膜の除去を試みた。
《比較例３》
実施例１においてウエットステーションで使用した１槽目および２槽目の剥離液を主成分がＯ，Ｏ’−ジクロロベンゼンである剥離液に替えた他は実施例１と同様の評価を行った。
《比較例４》
実施例１においてウエットステーションで使用した１槽目および２槽目の剥離液をジメチルスルホキシド単独の剥離液に替えた他は実施例１と同様の評価を行った。
以上、実施例１〜５、比較例１〜４の評価結果を表１に示す。
【００２４】
【表１】

【００２５】
【発明の効果】
本発明によって、耐熱性高分子膜の除去を効率よく、しかも有機溶剤を汚染することなく安全に容易に行うことができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing a heat-resistant polymer protective film, and more particularly to a method for removing a heat-resistant polymer protective film coated on a semiconductor device.
[0002]
[Prior art]
Conventionally, polyimide resin having excellent heat resistance and excellent electrical characteristics, mechanical characteristics, etc. has been used for the surface protection film and interlayer insulation film of semiconductor elements. There has been a demand for significant improvement in heat cycle resistance, heat shock resistance, and the like due to the thinning and downsizing of packages, and the transition to surface mounting by solder reflow, and higher performance resins have been required.
On the other hand, a technology for imparting photosensitivity to the polyimide resin itself has recently attracted attention, and it can be used to simplify a part of the pattern creation process, shortening the process and improving the yield. In addition, since a solvent such as N-methyl-2-pyrrolidone is required, there are problems in safety and handling.
[0003]
Therefore, a positive photosensitive resin that can be developed with an aqueous alkali solution has recently been developed. For example, Japanese Patent Publication No. 1-468662 discloses a positive photosensitive resin composed of a polybenzoxazole precursor and a diazoquinone compound. This has high heat resistance, excellent electrical properties, and fine processability, and has the potential not only for wafer coating but also as a resin for interlayer insulation.
[0004]
In recent years, such a photosensitive resin has been widely used as a surface protective film or an interlayer insulating film of a semiconductor element. However, on the side of manufacturing a semiconductor device, a polycrystal formed on a substrate due to problems in the process or the like. It is often necessary to remove the benzoxazole film or the like. However, since the polybenzoxazole film is usually subjected to heat treatment at 300 ° C. to 400 ° C., it is very difficult to remove.
Therefore, the polybenzoxazole film is not normally removed after the heat treatment, and products that have failed during the process have been discarded as defective products, but in recent years, for the purpose of reducing production costs, etc. There has been a strong demand for so-called reworkability in which a polybenzoxazole film that has become a non-defective product can be removed and applied again.
[0005]
[Problems to be solved by the invention]
The present invention relates to a method for removing a coated heat-resistant polymer protective film.
[0006]
[Means for Solving the Problems]
The present invention relates to a method for removing a heat-resistant polymer protective film in which a heat-resistant polymer protective film subjected to a heat treatment is dry-etched and then is removed by a step of immersing in a mixed organic solvent of dimethyl sulfoxide and monoethanolamine. It is. Furthermore, as a preferred embodiment, the dry etching process is a process using oxygen plasma, and the mixing ratio of the dimethyl sulfoxide and monoethanolamine is from 3:97 to 90:10, and the heat resistance The heat-resistant polymer protective film is a polybenzoxazole film or polyimide film represented by the following general formula, and the heat-resistant polymer protective film is a protective film formed on a semiconductor device. Is the method.
[0007]
[Chemical 1]

[0008]
DETAILED DESCRIPTION OF THE INVENTION
The dry etching process for removing the heat-resistant polymer protective film such as the polybenzoxazole film is performed for the purpose of cutting the polybenzoxazole film on the semiconductor device to a certain thickness. In the dry etching process, a process using oxygen plasma is preferable. In this case, only the organic film or the organic solvent on the substrate is etched, so that the substrate which is an inorganic film is not affected. In the case of dry etching treatment with a reactive gas using fluorine or chlorine radicals, substrates such as Si, SiO ₂ , Si ₃ N ₄ , and Al are etched, which is not preferable. When dry etching using oxygen plasma is performed at a high output, organic substances can be removed in a shorter time. Further, the temperature in the etching apparatus tank is preferably as high as possible. If preheating is performed with nitrogen or a mixed gas of nitrogen and hydrogen, the removal can be performed in a shorter time.
[0009]
The immersion treatment in the organic solvent is performed for the purpose of completely removing the polybenzoxazole film remaining on the semiconductor device after the dry etching treatment. Solvents with strong dissolving power for removing polybenzoxazole films include fuming nitric acid, halogen-based solvents, phenol-containing solvents and hydrofluoric acid, which are used for analysis of package defects, etc. Although these materials are mentioned, there are concerns about problems such as environmental problems and harmfulness to human bodies. Accordingly, it was considered preferable to use a safer solvent, and as a result of examining various solvents, it was found that a mixed solvent of dimethyl sulfoxide and monoethanolamine is excellent in dissolving a polybenzoxazole film or the like. Furthermore, the thing with much content of monoethanolamine is preferable. This is presumably because monoethanolamine having strong alkalinity has a mechanism for decomposing and dissolving the oxazole ring. By using the mixed organic solvent by heating, the polybenzoxazole film and the like can be removed in a shorter time. More preferably, it is possible to achieve a very low particle level by using a wafer cleaning apparatus having a plurality of cleaning tanks and vapor cleaning apparatuses widely used in mass production factories of semiconductor devices.
[0010]
The mixing ratio of dimethyl sulfoxide and monoethanolamine is from 3:97 to 90:10, preferably from 4:96 to 50:50, by weight. When the ratio of dimethyl sulfoxide is less than 3, the handleability is slightly deteriorated, and when it exceeds 90, the dissolution time becomes longer.
[0011]
In the present invention, by combining dry etching treatment with oxygen plasma and immersion treatment with a mixed organic solvent composed of dimethyl sulfoxide and monoethanolamine, the polybenzoxazole film can be removed and the particles can be reduced to a very low level. Is possible. In the case of only dry etching processing, it can be removed in a short time by processing at high temperature and high output, but the organic matter of the removed film may remain in the tank and reattach on the wafer substrate. This is not preferable because of concern. On the other hand, in the case of only the treatment by the immersion of the mixed organic solvent, not only a long time is required until the film is completely dissolved and removed, but there is a problem that the organic solvent in the immersion tank is significantly contaminated. In particular, when a wafer cleaning apparatus is used for a mass-produced product of a semiconductor device, the organic solvent is quickly contaminated and the dissolving power is lowered, which is not preferable. In the present invention, after reducing the film thickness in a short time by dry etching treatment, combining the immersion treatment with a mixed organic solvent composed of dimethyl sulfoxide and monoethanolamine, the organic solvent in the cleaning apparatus tank is remarkably reduced. The film can be removed without being contaminated, and the particles are reduced to a very low level.
[0012]
【Example】
Hereinafter, the present invention will be described specifically by way of examples.
Example 1
* Preparation of polybenzoxazole precursor 132.8 g (0.8 mol) terephthalic acid, 33.2 g (0.2 mol) isophthalic acid and 270.3 g (2 mol) 1-hydroxy-1,2,3-benzotriazole ) And 366.3 g (1.0 mol) of hexafluoro-2,2-bis (3-amino-4-hydroxyphenyl) propane. Were put into a four-necked separable flask equipped with a thermometer, a stirrer, a raw material inlet, and a dry nitrogen gas inlet tube, and 3000 g of N-methyl-2-pyrrolidone was added and dissolved. Thereafter, the mixture was reacted at 75 ° C. for 12 hours using an oil bath.
[0013]
Next, 32.8 g (0.2 mol) of 5-norbornene-2,3-dicarboxylic anhydride dissolved in 500 g of N-methyl-2-pyrrolidone was added, and the mixture was further stirred for 12 hours to complete the reaction. After filtering the reaction mixture, it was put into a mixed solution of water / methanol = 3/1, and the precipitate was collected by filtration, sufficiently filtered with water, dried under vacuum, and represented by the general formula (1). A polyamide (A-1) in which X is the following formula X-1, Y is the following formula Y-1 and Y-2, and E is the following formula E-1.
[Chemical formula 2]

[0014]
* Preparation of positive photosensitive resin composition 100 g of synthesized polyamide (A-1) and 25 g of diazoquinone (Q-1) having the structure of the following formula were dissolved in 200 g of N-methyl-2-pyrrolidone and stirred for 3 hours. . Thereafter, stirring was stopped and the mixture was allowed to stand at room temperature. After 3 hours, the appearance was visually observed. As a result, no bubbles were observed. Then, it filtered with the 0.2 micrometer Teflon filter, and obtained the photosensitive resin composition.
[Chemical 3]

[0015]
* Creation of cured polybenzoxazole film Using a positive photosensitive resin composition containing a polybenzoxazole precursor synthesized by the above method, a silicon wafer was coated with a spin coater and then heated at 120 ° C on a hot plate. The film was dried for 4 minutes to obtain a coating film having a thickness of about 11 μm. This coating film is exposed at an exposure amount of 500 mJ / cm ² through a reticle with an i-line stepper exposure machine NSR-2205i12C (manufactured by Nikon Corporation) and immersed in an aqueous 2.38% tetramethyl hydroxide solution for 100 seconds. Then, the exposed portion was dissolved and removed, and then rinsed with pure water for 30 seconds to form a pattern. This wafer was heated in an oven at 150 ° C. for 30 minutes and at 320 ° C. for 30 minutes to carry out a polybenzoxazole ring closure reaction to obtain a cured polybenzoxazole film having a final film thickness of about 8 μm.
[0016]
* Removal of polybenzoxazole cured film Wafer on which the above-mentioned cured polybenzoxazole film is formed using an etching apparatus OPM-EM1000 (manufactured by Tokyo Ohka Kogyo Co., Ltd.), using a mixed gas of nitrogen and hydrogen and oxygen. After raising the internal temperature to 200 ° C., oxygen plasma treatment was performed at 1000 W for 3 minutes to reduce the film thickness to 0.2 μm.
[0017]
Subsequently, washing with an organic solvent was performed at a wet station manufactured by Kaijo. In the wafer flow step, the first tank is processed at 100 ° C. for 30 minutes using a mixed organic solvent (hereinafter referred to as a stripping solution) whose composition is dimethyl sulfoxide / monoethanolamine = 4/6. In the 3rd tank, rinse with N-methyl-2-pyrrolidone for 10 minutes at room temperature, and in the 4th tank with pure water at 100 ° C for 30 minutes. It is a process of performing a treatment for 1 minute, performing a treatment for 3 minutes at room temperature with pure water in the 5th tank, performing a vapor drying of isopropyl alcohol for 4 minutes in the 6th tank, and finally performing spin drying. A polybenzoxazole cured film whose thickness was reduced by plasma treatment was treated in a wet station.
[0018]
* Evaluation after removal of the cured polybenzoxazole film For the wafer after the immersion treatment in the stripping solution, the number of particles having a particle size of 1 μm or more was measured using a laser surface inspection device LS-5000 (manufactured by Hitachi Electronics Engineering Co., Ltd.). The measurement result was 21.
[0019]
Example 2
The same evaluation as in Example 1 was performed except that the polybenzoxazole film in Example 1 was replaced with a polyimide film. A method for preparing a polyimide precursor and a cured film is described below.
[0020]
* Preparation of polyimide precursor A four-neck separable flask equipped with a thermometer, a stirrer, a raw material charging port, and a dry nitrogen gas inlet, 190.2 g (0.95 mol) of 4,4′-diaminodiphenyl ether, 1,3 -12.4 g (0.05 mol) of bis (3-aminopropyl) -1,1,3,3-tetramethyldisiloxane is taken, and anhydrous N-methyl-2-pyrrolidone is added to this An amount sufficient for the solid content ratio to be 15% by weight was added and dissolved. Next, the flask was immersed in an aqueous solution of 0 to 50 ° C., and 218.1 g (1 mol) of purified pyromellitic dianhydride was added while suppressing heat generation. After the tetracarboxylic dianhydride was dissolved, the temperature of the system was kept at 20 ° C. and the reaction was continued for 10 hours. The dry nitrogen gas was allowed to flow throughout the entire process from the preparation stage of the reaction to the removal of the product. The obtained product was a pale yellow viscous solution, and the intrinsic viscosity of a 0.5 wt% N-methyl-2-pyrrolidone solution was 1.1 (30 ° C.).
[0021]
* Preparation of cured polyimide film A synthesized polyimide precursor was applied onto a silicon wafer by a spin coater and then dried at 145 ° C for 1 minute on a hot plate to obtain a coating film having a thickness of about 11 µm. This coating film was coated with a positive photoresist OFPR-800 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) with a spin coater, dried at 100 ° C. for 1 minute, and further irradiated with 200 mJ / cm ² ultraviolet rays through a reticle. Then, the exposed portion was dissolved and removed by immersing in a 2.38% aqueous tetramethyl hydroxide solution for 60 seconds, and then rinsed with pure water for 30 seconds to form a pattern. Thereafter, the resist was peeled off by being immersed in butyl acetate for 1 minute. This wafer was heated in an oven at 150 ° C. for 30 minutes, 230 ° C. for 30 minutes, and 350 ° C. for 30 minutes to perform a polyimide ring-closing reaction, thereby obtaining a cured polyimide film having a final film thickness of about 6 μm.
[0022]
Example 3
The same evaluation as in Example 1 was performed except that the curing temperature of the polybenzoxazole film in Example 1 was changed to 350 ° C.
Example 4
In Example 1, the stripping solution in the first and second tanks used in the wet station was replaced with one having a composition of dimethyl sulfoxide / monoethanolamine = 6/4, and the heating temperature of the stripping solution was changed to 120 ° C. Otherwise, the same evaluation as in Example 1 was performed.
Example 5
In Example 1, the same treatment as in Example 1 was performed except that the stripping solution in the first and second tanks used in the wet station was a stripping solution having a composition of dimethyl sulfoxide / monoethanolamine = 4/96. And the same evaluation as in Example 1 was performed.
[0023]
<< Comparative Example 1 >>
In Example 1, an attempt was made to remove the cured polybenzoxazole film without performing the oxygen plasma treatment step.
<< Comparative Example 2 >>
In Example 1, the removal of the polybenzoxazole cured film was attempted only by the oxygen plasma treatment without performing the treatment of the stripping solution according to the present invention.
<< Comparative Example 3 >>
The same evaluation as in Example 1 was performed except that the stripping solution in the first and second tanks used in the wet station in Example 1 was replaced with a stripping solution whose main component was O, O′-dichlorobenzene.
<< Comparative Example 4 >>
The same evaluation as in Example 1 was performed except that the stripping solution in the first and second tanks used in the wet station in Example 1 was replaced with a stripping solution of dimethyl sulfoxide alone.
The evaluation results of Examples 1 to 5 and Comparative Examples 1 to 4 are shown in Table 1 above.
[0024]
[Table 1]

[0025]
【The invention's effect】
According to the present invention, the heat-resistant polymer film can be efficiently removed easily and safely without contaminating the organic solvent.

Claims (5)

Removal of heat-resistant polymer protective film characterized by comprising a process of dry-etching a heat-resistant polymer protective film, which is a polybenzoxazole film or polyimide film, and then immersing it in a mixed organic solvent of dimethyl sulfoxide and monoethanolamine Method. 2. The method for removing a heat-resistant polymer protective film according to claim 1, wherein the dry etching process is a dry etching process using oxygen plasma. The method for removing a heat-resistant polymer protective film according to claim 1, wherein the mixing ratio of dimethyl sulfoxide and monoethanolamine is from 3:97 to 90:10 by weight. 2. The method for removing a heat resistant polymer protective film according to claim 1, wherein the heat resistant polymer protective film is a protective film formed on a semiconductor device. The method for removing a heat-resistant polymer protective film according to claim 1, wherein the heat-resistant polymer protective film is a heat-treated protective film.