1223350 (1) 玖、發明說明 【發明所屬之技術領域】 本發明係相關於一種蝕刻製程方法，特別是，相關於 一種以電解之方式，實施遮罩鉻膜之蝕刻製程方法。 【先前技術】 經由微影術（lithography)形成遮罩（mask)之後， 需藉由蝕刻而對光阻底下之薄膜或是基底，進行選擇性的 鈾刻或是離子植入。 當今廣泛應用於半導體製程之蝕刻技術，主要有兩種 :一是濕式鈾刻（w e t e t c h i n g );另一是乾式融刻（d r y etching)。前一種主要係利用化學反應來進行薄膜之蝕刻 ;而後者則係利用接近物理之作用而進行蝕刻。 所謂「濕式蝕刻」，係利用擴散效應（diffusion ) ’ 而將鈾刻溶液中之反應物，通過一層極薄之邊界層（ boundary layer)，以到達被蝕刻薄膜之表面。經該反應 物與薄膜表面之分子產生化學反應，而生成各種化合物， 該些生成物之後經由擴散效應通過邊界層到溶液裡’而後 隨溶液被排出。此種藉由液態或是氣態之生成物而執行薄 膜分子之移除，因此沒有固定方向性’即所謂「等向性蝕 刻」（i s 〇 t r 〇 p h i c )。該濕式融刻之選擇性較佳。所謂「 選擇性（s e 1 e c t iv i t y )」係指蝕刻製程中對於被触刻薄膜 以及其他材質（例如光阻與基底）之鈾刻率比値。選擇性 高，代表蝕刻大都在被蝕刻材質上進行。由於濕式鈾刻係 -4- (2) (2)1223350 以化學方式進行蝕刻，可藉由對於溶液特性之判斷，而採 用大都只對蝕刻薄膜蝕刻之溶液，因此，其選擇性較高。 但疋’溶液齡刻濃度過局時，也會發生「底切（u n d e r c u t )現象」，所謂「底切現象」，如圖1所示，係在等向性 蝕刻下，造成光阻底下部份之薄膜被侵蝕。同時，由於等 向性蝕刻，而減低次微米圖樣（pattern)設置上之不確定 性。 所謂「乾式蝕刻」，係以電漿（plasma )進行薄膜蝕 刻之技術。對於低壓狀態之容器內氣體施以電壓，使原本 中性氣體分子被激發或解離成各種不同的帶電荷離子（ charged ion)、原子團（radicals)、分子以及電子。此 些例子之組成便稱爲電漿。電漿係氣體分子之崩潰狀態， 本身爲一導體，可傳送電流。將待蝕刻體，設置於連接陰 極，而使電漿與電極板間的電位差，加速帶正電荷離子， 而轟擊電極板之表面，以形成濺擊（sputtering)現象。 此乾蝕刻方式對於縱向蝕刻能力遠大於橫向蝕刻能力，因 此其具有極佳之非等向性（anisotrophic)(接近90度） ，如圖2所示。且，對於次微米圖樣之設置，由於有較佳 之「非等向性」，因此有較高之可靠性。但是，由於藉由 電荷離子「同時」轟擊電極板之表面，因此，被蝕刻薄膜 以及其他材質（例如光阻與基底）同時被轟即，而使得選 擇性較差。且，在瑕疵之控制較差。 【發明內容】 本發明之目的，在解決上述習知濕蝕刻以及乾蝕刻之 (3) (3)1223350 缺點’藉由採用電解之技術，而對於以鉻材質所製之遮罩 予以蝕刻之製程方法。 本發明採用技術成熟之電解技術，藉由將分子溶解技 術應用於遮罩蝕刻製程，而得到與乾蝕刻同樣功效之「次 微米圖樣之實施、較佳之圖樣可靠度以及較佳之重要大小 (C r i t i c a 1 d i m e n s i ο η )」等功效’此外’並可具有較佳之 瑕疵控制。 【實施方式】 以下，首先參考圖3至圖5而描述本發明之實施方式 〇 如圖3所示，係待蝕刻裝置1之構成；首先在基底2 之上，藉由物理氣相沈積（physical vapor deposition ; PVD)或是化學蒸氣沈積（Chemical Vapor Deposition; CVD )，而形成一鉻膜3 ;之後，藉由微影術之適當之圖 樣轉移（pattern transfer)，而形成光阻遮罩4。 在圖4中，將待蝕刻裝置1置於容器7中，而將該待 蝕刻裝置1置入塡滿電解溶液6之中’將鉻膜2之邊緣接 觸點接上電源5之正極8，而電源5之負極則與電解溶液 接觸，但不與待蝕刻裝置1直接接觸。 在圖5中，經由電解反應，而將待蝕刻裝置1之光阻 遮罩以及未覆蓋光阻遮罩之薄膜部份予以移除’僅留下原 有光阻遮罩覆蓋之薄膜部份。 (4) (4)1223350 【圖式簡單說明】 圖1係習知濕蝕刻所發生之底切現象之橫切面圖； 圖2係習知乾蝕刻之非等向性蝕刻之橫切面圖； 圖3係本發明之電解式遮罩鉻膜之蝕刻製程方法之第 一步驟； 圖4係本發明之電解式遮罩鉻膜之蝕刻製程方法之第 二步驟；以及 圖5係本發明之電解式遮罩鉻膜之蝕刻製程方法之第 三步驟。 主要元件對照表 1 待蝕刻裝置 2 基底 3 鉻膜 4 光阻遮罩 5 電源 6 電解溶液 7 容器 8 正極1223350 (1) Description of the invention [Technical field to which the invention belongs] The present invention relates to an etching process method, and in particular, to an etching process method for masking a chromium film by electrolysis. [Previous Technology] After the mask is formed by lithography, the film or substrate under the photoresist needs to be selectively etched or ion-implanted by etching. There are two main types of etching technology currently used in semiconductor processes: one is wet uranium etching (wet e t c h i n g); the other is dry melting etching (d r y etching). The former mainly uses chemical reactions to etch thin films, while the latter uses near physical effects to etch. The so-called "wet etching" is to use the diffusion effect to pass the reactants in the uranium etching solution through a very thin boundary layer to reach the surface of the etched film. The reactant reacts with molecules on the surface of the thin film to generate various compounds, and these products are then passed through the boundary layer into the solution through the diffusion effect 'and then discharged with the solution. This type of removal of thin film molecules is performed by a liquid or gaseous product, so there is no fixed directionality, which is the so-called "isotropic etching" (is s 0 t r 0 p h i c). The wet-melt engraving has better selectivity. The so-called "selectivity (s e 1 e c t iv i t y)" refers to the ratio of uranium etch rate to the touched film and other materials (such as photoresist and substrate) in the etching process. High selectivity, which means that most of the etching is performed on the material being etched. Because the wet uranium engraving system is chemically etched by -4- (2) (2) 1223350, the solution can be judged by the characteristics of the solution, and most of the solutions are only used to etch the etching film, so its selectivity is high. However, when the concentration of the solution is too high, the "undercut phenomenon" also occurs. The so-called "undercut phenomenon", as shown in Figure 1, is caused by isotropic etching, which causes the bottom part of the photoresist. The film is eroded. At the same time, due to the isotropic etching, the uncertainty in the sub-micron pattern setting is reduced. The so-called "dry etching" is a technique for performing thin-film etching with plasma. A voltage is applied to the gas in the low-pressure container to cause the original neutral gas molecules to be excited or dissociated into various charged ions, radicals, molecules and electrons. The composition of these examples is called plasma. Plasma is a collapsed state of gas molecules, which itself is a conductor and can carry electric current. The body to be etched is disposed on the connection cathode, so that the potential difference between the plasma and the electrode plate accelerates the positively charged ions, and bombards the surface of the electrode plate to form a sputtering phenomenon. This dry etching method is far better than the horizontal etching ability in the vertical etching ability, so it has excellent anisotrophic (close to 90 degrees), as shown in Figure 2. And, for the setting of sub-micron patterns, it has higher reliability because it has better "non-isotropic". However, due to the simultaneous bombardment of the surface of the electrode plate by the charged ions, the etched film and other materials (such as photoresist and substrate) are simultaneously bombarded, making the selectivity poor. Moreover, the control over defects is poor. [Summary of the invention] The purpose of the present invention is to solve the above-mentioned disadvantages of conventional wet etching and dry etching (3) (3) 1223350. The process of etching the mask made of chromium material by using electrolytic technology method. The invention adopts a mature electrolysis technology, and applies molecular dissolution technology to the mask etching process to obtain "sub-micron pattern implementation, better pattern reliability, and better important size (Critica) which have the same effect as dry etching. 1 dimensi ο η) "and other effects 'in addition' and can have better defect control. [Embodiment] Hereinafter, an embodiment of the present invention will be described first with reference to FIGS. 3 to 5. As shown in FIG. 3, the structure of the device 1 to be etched is shown. First, the substrate 2 is subjected to physical vapor deposition (physical deposition). Vapor deposition (PVD) or Chemical Vapor Deposition (CVD) to form a chromium film 3; after that, a photoresist mask 4 is formed by appropriate pattern transfer of lithography. In FIG. 4, the device 1 to be etched is placed in a container 7, and the device 1 to be etched is placed in a full electrolytic solution 6. The edge contact point of the chromium film 2 is connected to the positive electrode 8 of the power source 5, and The negative electrode of the power source 5 is in contact with the electrolytic solution, but is not in direct contact with the device 1 to be etched. In FIG. 5, the photoresist mask of the device 1 to be etched and the film portion not covered by the photoresist mask are removed through the electrolytic reaction ', leaving only the film portion covered by the original photoresist mask. (4) (4) 1223350 [Schematic description] Figure 1 is a cross-sectional view of the undercut phenomenon that occurs in conventional wet etching; Figure 2 is a cross-sectional view of the anisotropic etching in conventional dry etching; Figure 3 The first step of the etching method of the electrolytic mask chromium film of the present invention; FIG. 4 is the second step of the etching method of the electrolytic mask chromium film of the present invention; and FIG. 5 is the electrolytic mask of the present invention. The third step of the etching method of the chromium film. Comparison table of main components 1 Device to be etched 2 Substrate 3 Chromium film 4 Photoresist mask 5 Power supply 6 Electrolytic solution 7 Container 8 Positive electrode