九、發明說明： 【發明所屬之技術領域】 本發明係關於-種半導體製程方法，特別是有關於一 種金屬蝕刻之半導體製程方法。 【先前技術】 隨著工業技術之發展，半導體製程之空間尺度亦逐漸 縮小，以因應日漸複雜之超大型積體電路(Ukra Large Scale Integration (ULSI))的需求。微影技術的解析度限定 了半導體元件的最顿寬，*光阻層的厚度會影響所需圖 案的解析n光阻層的深寬比過大，曝光時可能會因為 某些光學效應’如干料，而嚴重影響_的解析度。因 此’隨著製姉界尺寸的減小’雜的厚度也需跟著下降。 然而，在金屬時，由於光阻與金屬之間的侧選 擇比很小(-般約為L6)’因此需要具有足夠厚度的光阻 才足以抵擋蝕刻劑的蝕刻。 因此，需要提供-種金屬侧方法，以降低在侧金 屬時所需的光阻層厚度。 【發明内容】 鑑於先則技#!"所存在的問題，本發明提供了一種金屬 钱刻方法，可降低所需光阻層的厚度。IX. INSTRUCTIONS OF THE INVENTION: TECHNICAL FIELD OF THE INVENTION The present invention relates to a semiconductor process method, and more particularly to a semiconductor process for metal etching. [Prior Art] With the development of industrial technology, the spatial scale of semiconductor processes has been gradually reduced to meet the needs of the increasingly complex Ukra Large Scale Integration (ULSI). The resolution of the lithography technology limits the maximum width of the semiconductor device. The thickness of the photoresist layer affects the resolution of the desired pattern. The aspect ratio of the n-resist layer is too large, and some optical effects may be caused by exposure. Material, and seriously affect the resolution of _. Therefore, as the size of the system is reduced, the thickness of the impurities also needs to decrease. However, in the case of metal, since the side selection ratio between the photoresist and the metal is small (-about about L6), it is necessary to have a photoresist having a sufficient thickness to withstand the etching of the etchant. Therefore, there is a need to provide a metal side method to reduce the thickness of the photoresist layer required for the side metal. SUMMARY OF THE INVENTION In view of the problems of the prior art #!", the present invention provides a metal money etching method which can reduce the thickness of a desired photoresist layer.
4NTC/06022TW : 93156TW 根據本發明之-方面，金屬餘刻方法 提供-基板；形成-金朗於基板之上；形成j下7: 於金屬層之上;圖案化氧化銘層 呂層 為罩幕，蝕刻金屬層。 口茶化虱化鋁層 根據本發明之另一方面，圖案化負 含下列步驟:形成-先阻層於氧化銘層之上:二= 化光阻層；以及嗎化先阻層為罩幕= 根據本發明之又—方面，金屬層為喊銅且其厚产介 於7000A至10000A '氧化紹層的厚度介於3〇〇入又至 700A、及光阻層的厚度小於12〇〇 a。 本發明之其他方面’部分將在後續說明中陳述，而部 分可由說明中輕易得知，或可由本發明之實施而得知。本 發明之各；ίτ ©將可利用後附之㈣專利範圍巾所特別指 出之元件及組合而理解並達成。需了解，先述的一般說明 及下列詳細說明均僅作舉例之用，並非用以限制本發明。 【實施方式】 本發明提供一種金屬蝕刻方法，可有效地減少所需的 光阻厚度。為了使本發明之敘述更加詳盡與完備，可參照 下列描述並配合圖1至圖3之圖式。然以下實施例中所述 4NTC/06022TW ： 93I56TW 6 之農置、元件及方法步驟’僅用以說明本發明，並非用以 限制本發明的範圍。 ▲於本發明之方法巾建立在基材上之各層物質，可以經 由熟習本項技藝者所知悉之方法來執行，例如沉積法 (deposition)，化學氣相沉積法(ehemiealdep〇siti〇n) 或原子層沉積法(atomic layer deposition (ALDX)。 參考圖1 ’本發明方法包含提供一基材1〇〇，其可使 用任何合適的半導體基材或習知的石夕晶圓、或是在積體電 路製作過程中任何需要進行金屬侧的適宜基材。然後， 形成一緩衝層110於基材100上，緩衝層11〇的材料可例 如但不限於鈦，厚度約為4GGA。接著，形成—金屬層12〇 於緩衝層110上。金屬層120的材料可例如為銘或銅，但 不以此為限，其厚度可依後續製程的設計需求而決定。在 本發明一實施例中，金屬層12〇的厚度為約7〇〇〇 Α至約 10000 A，較佳為8500 Α。之後，形成一阻障層13〇於金 屬層120上’此阻障層130係由一般習知技藝者所知之方 法’儿積鈦層、氮化鈦層或鈦及氮化欽的複合層於金屬層 120上，其中氮化鈦層約為4〇〇A，而鈦層約為5〇入。需 注意的是，阻障層130雖舉例為鈦、氮化鈦或其組合物而 但疋對於阻卩早層130材料的選用，可視不同需求而選擇不 同的材料。再者，鈦、氮化鈦或鈦/氮化鈦可以錢錢或沉 積的方式形成，亦可採用氮化步騾將鈦層轉變以形成氮化4NTC/06022TW: 93156TW According to the aspect of the invention, the metal residual method provides a substrate; forming - gold on the substrate; forming j under 7: over the metal layer; patterning the oxide layer to form a mask , etching the metal layer. According to another aspect of the present invention, the patterning negatively comprises the steps of: forming a first resist layer on the oxidized underlayer: two = a photoresist layer; and a first resist layer is a mask According to still another aspect of the present invention, the metal layer is copper and its thickness is between 7000A and 10000A. The thickness of the oxide layer is between 3 and 700A, and the thickness of the photoresist layer is less than 12〇〇a. . The other aspects of the invention will be set forth in part in the description which follows and may be readily understood by the description. Each of the present inventions; ίτ © will be understood and achieved by means of the elements and combinations specifically indicated in the appended claims. It is to be understood that the foregoing general description and the claims [Embodiment] The present invention provides a metal etching method which can effectively reduce the required photoresist thickness. In order to make the description of the present invention more detailed and complete, reference is made to the following description in conjunction with the drawings of Figures 1 to 3. However, the 4NTC/06022TW: 93I56TW 6 described in the following examples is merely illustrative of the invention and is not intended to limit the scope of the invention. ▲ The various layers of material established on the substrate by the method of the present invention can be performed by methods known to those skilled in the art, such as deposition, chemical vapor deposition (ehemiealdep〇siti〇n) or Atomic layer deposition (ALDX). Referring to Figure 1 'The method of the present invention comprises providing a substrate 1 〇〇 which can be used with any suitable semiconductor substrate or conventional lithographic wafer, or in-product Any suitable substrate for the metal side during the fabrication of the bulk circuit. Then, a buffer layer 110 is formed on the substrate 100. The material of the buffer layer 11 can be, for example, but not limited to, titanium, and has a thickness of about 4 GGA. The metal layer 12 is disposed on the buffer layer 110. The material of the metal layer 120 may be, for example, inscription or copper, but not limited thereto, and the thickness thereof may be determined according to the design requirements of subsequent processes. In an embodiment of the invention, the metal The thickness of the layer 12 is from about 7 Å to about 10000 Å, preferably 8500 Å. Thereafter, a barrier layer 13 is formed on the metal layer 120. The barrier layer 130 is conventionally known to those skilled in the art. Known method a titanium nitride layer or a composite layer of titanium and nitride is formed on the metal layer 120, wherein the titanium nitride layer is about 4 Å A and the titanium layer is about 5 〇. Note that the barrier layer 130 Although titanium, titanium nitride or a combination thereof is exemplified, but the material of the early layer 130 is selected, different materials may be selected according to different needs. Further, titanium, titanium nitride or titanium/titanium nitride may be used for money. Formed by money or deposition, or nitrided ruthenium can be used to transform the titanium layer to form nitride
4NTC/06022TW ： 93I56TW 1323295 鈦層。接著，沉積一氧化鋁(八12〇3)層14〇作為硬式遮罩， 其厚度為約300 A至700 A，較佳為500 A。然後，塗 佈一光阻層150於氧化链層140之上，其中光阻層150 的厚度一般小於1200 A。 接著，參考圖2，利用曝光顯影等圖案轉移技術來圖 案化光阻層150，以定義出所欲儀刻的區域。之後，以圖 案化光阻層150為罩幕，蝕刻氧化鋁層14〇，以將光阻層 150的圖案轉移至氧化鋁層14〇β在此需注意，在轉移光 阻層150圖案至氧化銘層mo時，光阻層15〇可能同時會 被去除或減損。接著，參考圖3，_餘的光阻層15〇及 圖案化後的氧化鋁層作為罩幕，依序蝕刻阻障層13〇、金 屬層120、及緩衝層ιω。 在本發明一實施例中，金屬層120及緩衝層110之勒 刻方式為乾蝕刻，蝕刻氣體可例如為CHF3& c]2。由於 ^屬（如銘或銅)與Al2〇3之間的侧選擇比很高（約為 )命因此選用八丨2〇3作為金屬蝕刻的硬式遮罩其厚度 L需ί太厚，而聽可以減少光阻厚度，提高曝光顯影的 斤又。此外，Α12〇3與金屬之間也具有良好的黏著度， 因此不會增加製程上發生失誤的風險。 上述之實施例係用以描述本發明，然本發明 構仍可有未麟本發明本質之修改與·。因此，本發明口4NTC/06022TW: 93I56TW 1323295 Titanium layer. Next, an aluminum oxide (eight 12 〇 3) layer 14 沉积 is deposited as a hard mask having a thickness of about 300 A to 700 Å, preferably 500 Å. Then, a photoresist layer 150 is applied over the oxidized chain layer 140, wherein the thickness of the photoresist layer 150 is generally less than 1200 Å. Next, referring to Fig. 2, the photoresist layer 150 is patterned by pattern transfer techniques such as exposure development to define the desired region. Thereafter, the patterned photoresist layer 150 is used as a mask, and the aluminum oxide layer 14 is etched to transfer the pattern of the photoresist layer 150 to the aluminum oxide layer 14 〇β. Note that the photoresist layer 150 is patterned to oxidize. When the layer mo is inscribed, the photoresist layer 15 may be removed or degraded at the same time. Next, referring to FIG. 3, the remaining photoresist layer 15 and the patterned aluminum oxide layer serve as a mask, and the barrier layer 13A, the metal layer 120, and the buffer layer ιω are sequentially etched. In an embodiment of the invention, the etching of the metal layer 120 and the buffer layer 110 is dry etching, and the etching gas may be, for example, CHF3 & c]2. Since the side selection ratio between the genus (such as Ming or copper) and Al2 〇3 is very high (about), it is necessary to use the 丨2〇3 as the hard mask of the metal etch. The thickness L needs to be too thick and thick. It can reduce the thickness of the photoresist and increase the exposure and development. In addition, Α12〇3 also has good adhesion to the metal, so it does not increase the risk of errors in the process. The above embodiments are intended to describe the present invention, but the present invention may still have modifications and modifications of the nature of the invention. Therefore, the present invention
WTC/06022TW : 93I56TW 8 1323295 並不限於以上特定實施例的描述，本發明的申請專利範圍 係欲包含所有此類修改與變化，以能真正符合本發明之精 神與範圍。 【圖式簡單說明】 圖1至圖3揭示根據本發明方法以製造一溝渠結構的 流程剖面圖。 • 【主要元件符號說明】 100 基材 110 緩衝層 120 金屬層 130 阻障層 140 氧化鋁層 150 光阻層WTC/06022TW: 93I56TW 8 1323295 is not limited to the description of the specific embodiments above, and the scope of the present invention is intended to embrace all such modifications and variations insofar. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 through 3 illustrate cross-sectional views of a process for fabricating a trench structure in accordance with the method of the present invention. • [Main component symbol description] 100 Substrate 110 Buffer layer 120 Metal layer 130 Barrier layer 140 Alumina layer 150 Photoresist layer
4NTC/06022TW ： 93156TW4NTC/06022TW : 93156TW