1299慨 九、發明說明： 【發明所屬之技術領域】 本發明是有關於微影(Lithography)方面的技術，且特 別是有關於一種檢驗相移式光罩(Phase Shift Mask，PSM) 之相移角（Phase-shift angle)的方法、利用此方法進行調校 的微影製程，以及相移式光罩之結構。此種相移式光罩的 相移角可藉由該方法得知。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the field of lithography, and in particular to a phase shift of a phase shift mask (PSM). The method of phase-shift angle, the lithography process using this method, and the structure of the phase shift mask. The phase shift angle of such a phase shift mask can be known by this method.
【先前技術】 丨通者和體％路(1(：)的集積度要求愈來愈高，先進半導 體製程的線寬(Linewidth)多已降至所用之曝絲源的波長 以下。當線寬降至曝光光源波長的一半左右時，即須使用 ^移f光罩進行_轉移，以提高解析度(ResQluti〇n;。一 、曼而言，相移式光罩係利用相鄰可透統之間的相角差 ^肖，阻層之需要低量曝光部分的級振幅，以減少 先別I，如此即可提高曝光對比，進㈣善解析度。〃 制相⑽’而此厚度難崎確控制，所_移^ = 從而降低解析度’並可能使—㈣程能力特徵 及/或是製程能力的聚隹深㈤^f位置(f_ eenter)，以 鍵尺寸等财縣。為Gf/_s，腳)與/或關 常須使用近接式探針測量相’相移式光罩進貨後通 厚度，以檢驗此光罩的相 同之透光區的基板或膜層 可調整曝光條件以補償卜°如發現相移角有誤差，即 、w、差，或是退回光罩公司重新校 12994】觀 3twfdoc/g 正並製作新的光罩。 不過，使用近接式探針測 板或臈層厚度的作法不但耗時，,f式光罩上各區域之基 面，致使微影餘的品質降丄叫也可能損傷光罩的表 【發明内容】 本發明的目的就是在提供一 角的方法，其不但树，又不=驗相移式光罩之相移 义本發明的再—目的 發明之相移角檢驗方法測 ^衣私、係利用本 本發明的又一目的是提供再據以調整製程條件。 有相移角測量圖案，以便工作其上配置 取得一類型之相移式光罩的相法如下：首先 的校正曲線。接著，將待檢驗之_二==特徵值 轉移至-光阻層上以形成光阻圖宰=光罩的圖案 ，徵值。然後依照上述校正曲線，由該梦;力 得該相移式光罩的實際相移角，以供檢ς、和政值推 關鍵尺寸。被檢驗之相移式光罩如依類型區分的 (Η蟲㈣相移式光罩、交替(AU_ting)相移式2 +調 鉻(Chromeless)相移式光罩，或是其他任 、热 的相移式光罩。另外，上述光阻圖案可=用2式原理 口陣列圖案’而用以定義此光阻圖案的曝光步驟[Prior Art] The integration of the %通者 and the body % road (1(:) is getting higher and higher, and the linewidth of the advanced semiconductor process has been reduced to less than the wavelength of the exposure source used. When it is reduced to about half of the wavelength of the exposure light source, it is necessary to use the shift mask to perform _ transfer to improve the resolution (ResQluti〇n; 1. For Man, the phase shift mask uses adjacent permeable system The phase angle difference between the two layers is required. The resistance layer needs the amplitude of the low-exposure portion to reduce the difference between the first and the second, so that the exposure contrast can be improved, and the (four) good resolution can be improved. The phase (10)' and the thickness of the layer Exactly control, _ shift ^ = thus reduce the resolution 'and may make - (four) process capability characteristics and / or process capability of the convergence depth (five) ^ f position (f_ eenter), with the key size and other financial district. For Gf / _s, foot) and / or off must always use the proximity probe to measure the phase thickness of the phase-shifting reticle after purchase, to verify that the substrate or film of the same light-transmissive area of the reticle can adjust the exposure conditions to compensate If you find that there is an error in the phase shift angle, ie, w, poor, or return to the mask company re-school 12994] view 3twfdo c/g is making a new mask. However, the use of the proximity probe board or the thickness of the layer is not only time-consuming, but also the base surface of each area on the f-type mask, resulting in the degradation of the quality of the lithography. BACKGROUND OF THE INVENTION The object of the present invention is to provide a method of cornering, which is not only a tree, but also a phase shift of the phase shifting reticle. Another method of the present invention is to provide a basis for adjusting the process conditions. There is a phase shift angle measurement pattern for working on a phase method in which a type of phase shift mask is obtained as follows : The first calibration curve. Next, the _2 == feature value to be tested is transferred to the photoresist layer to form a pattern of the photoresist pattern = reticle, and the value is then calculated. Then according to the above calibration curve, the dream; The actual phase shift angle of the phase-shifting reticle is used for inspection and the political value to push the key dimensions. The phase-shifting reticle to be inspected is classified according to type (aphid (four) phase-shifting reticle, alternating (AU_ting) phase shifting 2 + chrome (Chromeless) phase shift mask, or other , The thermal phase-shifted mask. Further, the photoresist pattern may be of formula 2 with the principles port array pattern = 'for exposing the photoresist pattern to define this step
1299傲 fd。, 曝光步驟或濕式曝光步驟。 政’當上述光阻圖案為平行線圖案時，用以反推相 ^程能力特徵值可絲焦位置絲焦深度。當上述 移工、光罩之類型為半調相移式光罩，且光阻圖案為開口 P歹〗圖案日守，用以反推相移角的製程能力特徵值可為聚焦 4置或♦焦深度。當相移式光罩之類型為無鉻相移式光 罩’且光阻圖案為開Π陣顧鱗，用以反推相移角的 程能力特徵值亦可為聚焦深度絲纽置。 、 另外，上述之相移角對應該製程能力特徵值的校正曲 ，、’例如可以相移角已知且各不相同的一系列相移式光罩 標準片進行微影製程，並測量該製程能力特徵值，而後 相移角作圖而得。 本杳明之微影製程如下··首先取得一類型之相移式光 罩的相移角對應一製程能力特徵值的校正曲線，再使用該 類型·之^目料鮮進行枝步驟，姻量前述餘能力特徵 值。接著依照該校正曲線，由前述製程能力特徵值推得相 移式光罩的實際相移角，再依照實際的相移角調整曝光條 件，以使此製程能力特徵值達到預設值。 簡言之，本發明之微影製程係利用上述本發明之相移 角檢驗方法得知實際的相移角，再據以調整曝光條件。此 微影製程的其他相關特徵，即與製程能力特徵值種類、相 移式光罩類型、欲轉移之圖案的型態、乾濕曝光方式及校 正曲線求法等相關的特徵則與前述者相同。 本發明之相移式光罩包括透明基板、積體電路圖案 (g 1299慨 twf.doc/g 區’以及至少-相移角測量圖案。其中 ==基板上，相移角測量圖案則位於積體電路圖^ f邊的透鴨板上。顏電路_與购㈣ = 同的多個第一區域與第二區域，且積體電路圖 二第ί7二區域的排列方式與相移角測量圖案中的第 弟一區域的排列方式相同。 是透0〔基板通常呈矩形’而相移角測量圖案例如 別位於透明基板的四角。相移_量_ ，可位在透明基板的四邊上，其數目不限制為4個。另外， 光罩之類型可為半調式、交替式、無鉻式或其他 用以而=電路圖案與相移角測量圖案例如皆包括 用以形成千仃線或開口陣列的圖案 =量嶋 式光罩之類型可為半調式或無路式。此外， u —區域的透明基板例如呈凹陷狀以產生一相移角。 曲味由明ΐ相移角檢驗方法係依照事先取得之校正 ^故錄力特徵值反推出相移式光罩的相移 ^十刀即省時間’又不會損害光罩。同時，由於f程 深度或聚焦位置等可在曝光後測得以 成相私角，故本發明之微影製程的 誤差，進而使製程能力特徵值達二 的周=置^本發明之相移式光罩在其積體電路圖案區 邊置有相移角測量圖案，所以在檢驗相移式光罩的1299 proud fd. , exposure step or wet exposure step. When the above-mentioned photoresist pattern is a parallel line pattern, it is used to reverse the phase characteristic ability value to the wire focal position. When the type of the above-mentioned shifting and reticle is a half-tone phase shifting reticle, and the photoresist pattern is an opening P歹 pattern, the process capability characteristic value for reversing the phase shift angle may be a focus 4 or ♦ Depth of focus. When the type of the phase shifting reticle is a chrome-free phase shifting reticle ′ and the photoresist pattern is an open-circle reticle, the characteristic value of the process for reversing the phase shift angle may also be a focused depth wire. In addition, the above-mentioned phase shift angle corresponds to the correction curve of the process capability characteristic value, and 'for example, a series of phase shift mask standard sheets having known phase shift angles and different degrees are subjected to the lithography process, and the process is measured. The ability characteristic value is obtained by plotting the phase shift angle. The lithography process of the present invention is as follows: First, a phase shift angle of a type of phase shifting reticle is obtained corresponding to a calibration curve of a process capability characteristic value, and then the branching step is performed using the type of material Remaining feature value. Then, according to the calibration curve, the actual phase shift angle of the phase shift mask is derived from the process capability characteristic value, and the exposure condition is adjusted according to the actual phase shift angle, so that the process capability characteristic value reaches a preset value. Briefly, the lithography process of the present invention utilizes the phase shift angle test method of the present invention described above to determine the actual phase shift angle and to adjust the exposure conditions accordingly. Other related features of the lithography process, that is, characteristics related to the type of process capability characteristic value, the type of phase shift mask, the pattern of the pattern to be transferred, the wet and dry exposure mode, and the correction curve are the same as those described above. The phase shifting reticle of the present invention comprises a transparent substrate, an integrated circuit pattern (g 1299 twf.doc/g area ' and at least a phase shift angle measurement pattern. wherein == on the substrate, the phase shift angle measurement pattern is located in the product The body circuit diagram ^ f on the duck plate. The color circuit _ and purchase (four) = the same multiple first and second regions, and the integrated circuit diagram of the second 的7 second region and the phase shift angle measurement pattern The arrangement of the first brother is the same. It is 0 [the substrate is usually rectangular] and the phase shift angle measurement pattern is, for example, located at the four corners of the transparent substrate. The phase shift _ quantity _ can be located on the four sides of the transparent substrate, the number of which is not The limit is 4. In addition, the type of the mask may be semi-tune, alternating, chrome-free or the like. The circuit pattern and the phase shift angle measurement pattern include, for example, patterns for forming a Millennium line or an array of openings. = The type of reticle type mask can be half-tone or no-path. In addition, the transparent substrate of the u-area is, for example, concave to generate a phase shift angle. The curve is determined by the alum phase shift angle method. Correction The phase shift of the reticle ^10 knives saves time' without damaging the reticle. At the same time, since the f-depth or focus position can be measured as a phase private angle after exposure, the error of the lithography process of the present invention And then the process capability characteristic value reaches two weeks = the phase shifting reticle of the present invention has a phase shift angle measurement pattern on the side of the integrated circuit pattern area, so in the inspection of the phase shift mask
I2994?44Qwfdoc/g 相移角時，只要針對相移角測量圖案即可，其不僅較為簡 便’同時也不會影響積體電路圖案的轉移。 為讓本發明之上述和其他目的、特徵和優點能更明顯 易懂，下文特舉較佳實施例，並配合所附圖式，作詳細說 明如下。 【實施方式】 圖1繪示本發明之檢驗相移式光罩相移角的方法的流 私圖。請參照圖1，首先取得欲使用之特定類型相移式光 罩的相移角對應一製程能力特徵值的校正曲線（步驟 100)，其中相移式光罩的類型例如為半調式、交替式、無 鉻式，其他任何型式，製程能力特徵值則例如為聚焦深 度、聚焦位置或光阻圖案的關鍵尺寸。此校正曲線例如可 以使用相移角已知且各自不同的一系列相移式光罩標準片 進仃微影製程，再以測得之製程能力特徵值對相移角作圖 =得，其中各相移式光罩標準片的相移角可以前述近接式 板針進行精確的測量。 著’於步驟UG巾，將待檢驗之該類型相移式光罩 、二=轉私至光阻層上以形成光阻圖案，並測量上述製 值。當欲測量之製程能力特徵值為聚焦深度或 其㈣可在曝光步驟後進行；當欲測量之製 為光阻圖案的關鍵尺寸時，其量測則須待顯 用以定義光阻圖案之曝光步驟例如是- 物鏡^光2 切光轉，後麵祕光光學系統的 兄與植層之岐人紐介質，_少紐進入光阻層When the phase shift angle is I2994?44Qwfdoc/g, it is only necessary to measure the pattern for the phase shift angle, which is not only simple but does not affect the transfer of the integrated circuit pattern. The above and other objects, features and advantages of the present invention will become more <RTIgt; [Embodiment] FIG. 1 is a flow chart showing a method of inspecting a phase shifting reticle phase shift angle of the present invention. Referring to FIG. 1, firstly, a phase-shifting angle of a specific type of phase shifting reticle to be used is used to obtain a calibration curve corresponding to a process capability characteristic value (step 100), wherein the type of the phase shifting reticle is, for example, a half-tone type or an alternating type. The chrome-free type, any other type, the process capability characteristic value is, for example, the focus depth, the focus position, or the critical size of the photoresist pattern. For example, the calibration curve can be processed by using a series of phase-shifting reticle standard films whose phase shift angles are known and different from each other, and then plotting the phase shift angles with the measured process capability characteristic values. The phase shift angle of the phase shift mask standard sheet can be accurately measured by the aforementioned proximity type plate needle. In the step UG towel, the phase shift mask of the type to be inspected, and the second layer are transferred to the photoresist layer to form a photoresist pattern, and the above-mentioned value is measured. When the process capability characteristic value to be measured is the depth of focus or (4) can be performed after the exposure step; when the system to be measured is the critical size of the photoresist pattern, the measurement is required to be used to define the exposure of the photoresist pattern. The steps are, for example, - the objective lens ^ light 2 cut light, the back of the secret optical system brother and the implant layer of the new medium, _ less New into the photoresist layer
1299氣。c/g ^折射作用’從而提高製程的解析度。另外，轉移至光阻 i之圖案的型態例如是平行線圖案或開口陣列圖案 接著’依照上述校正曲線，由該製程能力特徵值反推 亍相移式光罩的實際相移肖，以供檢驗(步驟120)。 、，圖2繪示本發明之微影製程的流程圖。請參照圖2， =取得-類型之相移式光罩的相移角對應—製程能力特 :的杈正曲線(步驟200)’其中相移式光罩的類型、製程 ^特徵值的麵、欲形成之絲圖案的型態及校正^線 的取得方法皆例如為前述者。接著使m細型之相移式光罩 進仃曝光轉’動】量前述製程能力特徵值（步驟叫。 然後，依照上述校正曲線，由此製程能力特徵值反推得 相移式光罩的實際相移角（步驟22G)，再依照實際的相移角 =整曝光條件，以使此製減力賴值達到預設值(步 230)，以符合所需。 ，另一方面，圖3A、3B.示本發明較佳實施例之相移 j光罩的一例相移式光罩3〇〇包括中央的積體電路圖案 2 302，以及配置在積體電路圖案區302外圍的相移角測 置圖案31G，其具有與频電路®案區302之局部相同的 相移式圖案，且係與積體電路圖案區302同時形成，從而 具有相同的相移角。由於相移角測量圖案310位在積體電 路圖案區302的外圍，故對應相移角測量圖案3ι〇之光阻 圖案係位在晶圓的切割道上(未繪示）。 在圖3A的例子中，共有4個相移角測量圖案Μ。分 別配置在矩形之相移式光罩3〇〇 $ 4個角落；而在圖3b I299iiQvf.d〇c/g 的例子_，相移角測量圖案3I0則配置在矩形相移式光罩 300的4邊上。不過，相移角測量圖案310的數目並不限 制為4個，且可配置在積體電路圖案區302周邊的任何其 他位置上，只要不與原先存在之對準標記或其他 衝突即可。 圖4A〜4C繪示本發明較佳實施例中，用以定義平行線 圖案的3種不同類型相移式光罩上的相移角測量圖案的範 例，其局部結構的上視圖與剖面圖。 圖4A例示用以形成平行線圖案之半調相移式光罩上 的相移角测量圖案的局部上視圖與剖面圖。此相移角測量 圖案310包括線狀透光區312及與其相位角差異達1肋度 的線狀半透光區314，其中透光區312與半透光區314交 替排列，且半透光區314之透光率通常為6%。半透光區 3M的低透光率例如是以形成在基板3〇上的極薄半透明鉻 (Cr)或矽化鉬(MoSi)金屬膜314a來達成。一般而言，半透 光區314係以金屬膜314a之厚度產生接近18〇度的相移 角，而透光區312處的基板30經過金屬膜314a的圖案化/ 蝕刻步驟後形成溝渠312a。控制透光區312的溝渠3'12& 沬度以使透光區312與半透光區314之間有最適合的相角 差(如180度）’即可提高曝光對比以改善解析度。 圖4B例示用以形成平行線圖案之交替相移式光罩上 的相移角測量圖案的局部上視圖與剖面圖。此相移角測量 圖案310包括線狀透光區322、與透光區322之相位角差 異達180度的線狀透光區324，以及線狀不透光區326。其 11 I2994iQw,doc/g 中各透光區322與透光區324交替排列，且任二相鄰透光 區322與324之間有一不透光區326。不透光區326例如 是以形成在基板30上的較厚鉻金屬膜326a來阻擋光線， 而透光區322的基板30例如是經過蝕刻形成溝渠322a， 使得透光區322與透光區324的基板厚度不同，而產生相 移角。 圖4C例示用以形成平行線圖案之無鉻相移式光罩上 的相移角測量圖案的局部上視圖與剖面圖。此相移角測量 圖案310包括線狀透光區332及與其相位角差異達18〇度 的較窄的線狀透光區334，其中透光區332與透光區334 ^替排列。由於透光區334較窄且與透光區332的相位角 差180度，所以對應透光區334及各透光區％】兩側鄰近 透光區334部分的光阻層部分的曝光劑量不足，而可成為 圖案(使用正光阻時)或無法形成圖案(使用負光阻時）。另 外、透光區334的基板3〇例如是經過钱刻形成溝渠3施 (或，光區332的基板3〇經過钮刻以形成溝渠[未緣示])， 使得透光區332與透光區334的基板厚度不同，而產生相 本發明較佳實施例中，用以形成開口陣列 二彭丨^叫式光罩上相移肖測量®案的局部結構上視 。此相移角測量圖案31G包括對應開口區域的 苴中料^與其相位角差異達180度的半透光區344， ;氏1= 之透光率通常為6%。半透光區344的 低透光相如以戦在餘3Q上触薄 121299 gas. c/g ^refracting effect to improve the resolution of the process. In addition, the pattern transferred to the pattern of the photoresist i is, for example, a parallel line pattern or an open array pattern. Then, according to the above calibration curve, the actual phase shift of the phase shift mask is reversed by the process capability characteristic value for Verify (step 120). 2 shows a flow chart of the lithography process of the present invention. Referring to FIG. 2, the phase shift angle of the phase-shifting reticle of the -type-corresponding-process capability is: a 杈-curve curve (step 200), wherein the type of the phase-shifting reticle, the surface of the process eigenvalue, The form of the wire pattern to be formed and the method of obtaining the correction wire are, for example, the foregoing. Then, the m-type phase-shifting reticle is moved into the 仃 exposure to turn the 'movement' amount of the aforementioned process capability characteristic value (step is called. Then, according to the above calibration curve, the process capability characteristic value is inversely derived to obtain the actual phase shifting reticle The phase shift angle (step 22G) is further adjusted according to the actual phase shift angle = the entire exposure condition so that the system relieving the value reaches a preset value (step 230) to meet the desired. On the other hand, FIG. 3A. 3B. An example of a phase shift mask of a preferred embodiment of the present invention includes a central integrated circuit pattern 2 302, and a phase shift angle configuration disposed on the periphery of the integrated circuit pattern region 302. The pattern 31G has the same phase shift pattern as that of the portion of the frequency circuit ® case 302, and is formed simultaneously with the integrated circuit pattern region 302 so as to have the same phase shift angle. Since the phase shift angle measurement pattern 310 bits At the periphery of the integrated circuit pattern region 302, the photoresist pattern corresponding to the phase shift angle measuring pattern 3 〇 is located on the scribe line of the wafer (not shown). In the example of FIG. 3A, there are 4 phase shift angles. Measure the pattern Μ. The phase shift masks arranged in a rectangle are respectively 3〇〇$ 4 In the example of I299iiQvf.d〇c/g of Fig. 3b, the phase shift angle measurement pattern 3I0 is disposed on the four sides of the rectangular phase shift mask 300. However, the number of phase shift angle measurement patterns 310 is not The limit is 4, and can be disposed at any other position around the integrated circuit pattern area 302 as long as it does not conflict with the original existing alignment mark or the like. 4A to 4C illustrate the preferred embodiment of the present invention. An example of a phase shift angle measurement pattern on three different types of phase shift masks for defining parallel line patterns, a top view and a cross-sectional view of a partial structure. Fig. 4A illustrates a halftone phase for forming a parallel line pattern. A partial top view and a cross-sectional view of the phase shift angle measurement pattern on the shift mask. The phase shift angle measurement pattern 310 includes a linear light transmitting region 312 and a linear semi-transmissive region 314 having a phase angle difference of 1 rib. The light transmissive region 312 and the semi-transmissive region 314 are alternately arranged, and the light transmittance of the semi-transmissive region 314 is usually 6%. The low light transmittance of the semi-transmissive region 3M is, for example, formed on the substrate 3〇. Extremely thin translucent chromium (Cr) or molybdenum molybdenum (MoSi) metal film 314a is achieved. The semi-transmissive region 314 generates a phase shift angle of approximately 18 degrees by the thickness of the metal film 314a, and the substrate 30 at the light-transmitting region 312 forms a trench 312a after the patterning/etching step of the metal film 314a. The trench 3'12& of the region 312 has a temperature so that the most suitable phase angle difference (e.g., 180 degrees) between the light transmissive region 312 and the semi-transmissive region 314 can improve the exposure contrast to improve the resolution. Figure 4B illustrates A partial top view and a cross-sectional view of a phase shift angle measurement pattern on an alternate phase shift mask for forming a parallel line pattern. The phase shift angle measurement pattern 310 includes a linear light transmissive region 322 and a phase with the light transmissive region 322. A linear light-transmissive region 324 having an angular difference of up to 180 degrees, and a linear opaque region 326. The light-transmitting regions 322 and the light-transmitting regions 324 are alternately arranged in the 11 I2994iQw, doc/g, and an opaque region 326 is disposed between any two adjacent light-transmitting regions 322 and 324. The opaque region 326 blocks light, for example, by a thicker chrome metal film 326a formed on the substrate 30, and the substrate 30 of the light-transmitting region 322 is etched to form a trench 322a, such that the light-transmitting region 322 and the light-transmitting region 324 are formed. The thickness of the substrate is different, and a phase shift angle is generated. Figure 4C illustrates a partial top view and a cross-sectional view of a phase shift angle measurement pattern on a chrome-free phase shift mask for forming parallel line patterns. The phase shift angle measuring pattern 310 includes a linear light transmitting region 332 and a narrow linear light transmitting region 334 having a phase angle difference of up to 18 degrees, wherein the light transmitting region 332 and the light transmitting region 334 are alternately arranged. Since the light-transmitting region 334 is narrow and the phase angle difference from the light-transmitting region 332 is 180 degrees, the exposure dose of the portion of the photoresist layer corresponding to the light-transmitting region 334 and the light-transmitting region 334 is insufficient. It can be a pattern (when a positive photoresist is used) or a pattern cannot be formed (when a negative photoresist is used). In addition, the substrate 3 of the light-transmitting region 334 is, for example, formed by the money-forming trench 3 (or the substrate 3 of the light region 332 is stamped to form a trench [not shown]), so that the light-transmitting region 332 and the light-transmitting region The thickness of the substrate of region 334 is different, and the resulting phase of the preferred embodiment of the present invention is used to form a partial structure top view of the phase shifting on the open array. The phase shift angle measuring pattern 31G includes a semi-transmissive region 344 corresponding to the opening region of the opening region and having a phase angle difference of 180 degrees, and the light transmittance of the lens 1 = 1 is usually 6%. The low light transmission phase of the semi-transmissive region 344 is as thin as the 3 on the remaining 3Q.
1299440 17043twf.doc/g 屬膜344a來達成。如同圖4A之例，半透光區344係以金 屬膜314a之厚度產生接近18〇度的相移角，而透光區342 處的基板30經過金屬膜314a之圖案化蝕刻步驟即形成溝 渠342a。控制透光區342的溝渠342a深度以使透光區342 與半透光區344之間有最適合的相角差，即可提高曝光對 比以改善解析度。 圖5B、5C則例示可配置在用以形成開口圖案之無鉻 相移式光罩上的兩種相移角測量圖案，其局部結構的上視 圖與剖面圖。圖5B所示為傳統的無鉻相移式光罩的開口 陣列圖案，其包括對應開口區域的透光區352及與其相位 角差異達180度的格狀透光區354。格狀透光區354的基 板30例如是經過蝕刻形成格狀的溝渠354a (或透光區352 的基板30經過蝕刻而形成凹洞[未繪示])，使得透光區352 與透光區354的基板厚度不同，而產生相移角。 然而，在應用圖5B所示之傳統開口陣列圖案時，4 個透光區352之間的部分透光區354之透過光的振幅常無 法被有效抵消，致使光阻層上的4個開口之間產生小孔 洞。因此，圖5C所示之特殊設計係將4個對應開口區之 透光區362之間的區域改成相位角與透光區362相同的透 光區366,其相位角與兩相鄰透光區362之間的透光區允斗 差180度，故其透過光的振幅會被其四周的透光區364有 效抵消，而不會造成光阻層上額外的小孔洞。另外，透光 區364的基板30例如是經過蝕刻形成短的溝渠％^ (或透 光區362及366的基板30經過餘刻而形成相連的大小凹洞 ⑧ 13 1299440 17043twf.doc/g [未繪示])，使得透光區362/366與透光區364的基板厚度 不同，而產生相移角。 圖6/7/8顯示在欲形成之光阻圖案為平行線圖案的情 形下，使料_韻祕式光罩及曝光方式(乾或濕式) 時，聚焦珠度/關鍵尺寸/聚焦位i與相移角之關係的電腦 ' 模擬結果。 由圖6 了知’此例中無論相移式光罩之類型為半調式 (代號HT)、交替式(代號Alt_PSM)或無鉻式(代號CPL)， 且無論曝光方式為乾式或濕式，聚焦深度對相移角之變化 皆不敏感。圖案為因此，當欲形成之光阻平行線圖 並不適合以聚焦深度來反推相移角。 另由圖7可知，此例中關鍵尺寸對相移角變化的靈敏 度略南於聚焦沬度對相移角之變化的靈敏度，而勉強可用 以反推相移角。然而，由圖8可知，聚焦位置對相移角變 化呈線性關係，且靈敏度大多在5nm/度以上。因此，當欲 形成之光阻圖案為平行線圖案時，較佳選用聚焦位置作為 g· 反推相移角的參數。 … 圖9/10顯示在欲形成之光阻圖案為開口陣列圖案，且 λ 光罩類型為半調相移式光罩的情形下，聚焦深度/聚焦位置 * 與相移角之關係的電腦模擬結果。 由圖9可知，此情形下聚焦深度幾乎不隨相移角之變 化而改變，故不適合選用為反推相移角的曝光參數。反之^ 由圖10可知，此情形下聚焦位置隨相移角改變之變化十分 明顯，故較適合選用為反推相移角的曝光參數。 14 1299440 17043twf.doc/g ，M2 _在欲形成之光阻圖案為開口陣列 且光罩類㈣無鉻鄉式光罩的情 隹、 置與相移角之關係的電腦模擬Μ # Λ二…，木度/來焦位 結構如圖5C所示之特殊言 其中光罩圖案之局部 由圖11與12可知，當欲形士 圖案，且光罩類型為無鉻二開口， 位置隨相移角改變之變化皆頗Α 才來…、冰度與水焦 為反推相移角的曝光=員為明顯’故二者皆適合選用 如上所述’本發明之相移角檢驗方 之校正曲線，由對應之製程能 =，、、爭先取付 相移角，故可節省時間，===推相移式光罩的 度或聚焦位置等製程能力特徵可在 ==::角&故本發明之微影製程的曝光 條件了k速肩正以補知相移角的誤差，進而使該 特=達到預設值，以提高圖案轉移的正確性、匕 二==罩㈣有相移角測量圖案，所以檢驗 姊角广、要針對相移角測量时即可，其不 便’同％•也不會影響積體電路_的轉移。 … 雖然本發明6以触實施觸露如上，然 限定本發明，任何熟習此技蓺者 和範圍内，當可作些許之不:縣發明之精神 範圍當視後附之申請專利範圍所 ^本發明之保護 【圖式簡單說明】 圖11 會示本發明之檢驗相移式光罩相移角的方法的流 15 1299440 17043twf.doc/g 程圖。 圖2繪示本發明之微影製程的流程圖。 圖3A、3B繪示本發明較佳實施例之相移式光罩的二 例，其差別在於相移角測量圖案的擺放位置不同。 圖4A〜4C例示本發明較佳實施例中，用以定義平 圖案的3種不同類ϋ相移式光罩上的相移角測量圖案的^ 例’其局部結構的上視圖與剖面圖。 " 圖5Α例示本發雜佳實施例中，㈣形成開口陣列 圖案之半咖移式光罩上相移制制案 圖與剖面圖；㈣、5C則例示兩種無鉻式相:式= 相移角測量圖案的局部結構的上視圖與剖面圖/九罩上 圖ό、7、8緣示在欲形成之光阻圖 情形下，使用不同型態的相移式光罩及曝、弁方丁^圖案的 式)時，聚焦深度/關鍵尺寸/聚隹 ^ '(乾式或濕 腦模擬結果。 之關係的電 且光】二之光阻圖案為開口陣列圖案， 卓i心為+调相移式光罩的情形下 置與相移肖之關係的電腦模擬結果。 “、、讀/承焦位 圖11、12繪示在欲形成 =草㈣為胁_式料的㈣圖隹案， 結果，其；;= [主要元件符號說明】 100〜120、200〜230 :步驟標號 16 1299燃 doc/g 30 :透明基板 300 :光罩 302 :積體電路圖案區 310 :相移角測量圖案 312、322、324、332、334、342、352、354、362、364、 366 :透光區 314、344 :半透光區 314a、344a :金屬膜1299440 17043twf.doc/g is achieved by the membrane 344a. As in the example of FIG. 4A, the semi-transmissive region 344 generates a phase shift angle of approximately 18 degrees by the thickness of the metal film 314a, and the substrate 30 at the light-transmitting region 342 forms a trench 342a through the patterned etching step of the metal film 314a. . The depth of the trench 342a of the light-transmissive region 342 is controlled such that there is an optimum phase angle difference between the light-transmitting region 342 and the semi-transmissive region 344, so that the exposure contrast can be improved to improve the resolution. 5B and 5C illustrate top and bottom cross-sectional views of a partial structure of two phase shift angle measurement patterns which can be disposed on a chrome-free phase shift mask for forming an opening pattern. Figure 5B shows an open array pattern of a conventional chrome-free phase shift reticle comprising a light transmissive region 352 corresponding to the open region and a latticed light transmissive region 354 having a phase angle difference of up to 180 degrees. The substrate 30 of the transparent light-transmissive region 354 is, for example, a trench 354a which is etched to form a lattice (or the substrate 30 of the light-transmitting region 352 is etched to form a recess [not shown]), so that the light-transmitting region 352 and the light-transmitting region The substrate thickness of 354 is different, and a phase shift angle is generated. However, when the conventional aperture array pattern shown in FIG. 5B is applied, the amplitude of the transmitted light of the partial light-transmitting region 354 between the four light-transmitting regions 352 is often not effectively canceled, resulting in four openings on the photoresist layer. Small holes are created between them. Therefore, the special design shown in FIG. 5C changes the area between the four light-transmissive areas 362 corresponding to the open areas to the same light-transmitting area 366 whose phase angle is the same as that of the light-transmitting area 362, and the phase angle and the two adjacent light-transmitting areas. The light-transmissive area between the regions 362 is 180 degrees out of tolerance, so that the amplitude of the transmitted light is effectively offset by the light-transmitting region 364 around it without causing additional small holes in the photoresist layer. In addition, the substrate 30 of the light-transmitting region 364 is, for example, etched to form a short trench %^ (or the substrate 30 of the light-transmitting regions 362 and 366 is formed to form a connected large-sized recess 8 13 1299440 17043 twf.doc/g [not The light-emitting region 362/366 is different from the substrate thickness of the light-transmitting region 364 to produce a phase shift angle. Figure 6/7/8 shows the focus bead/key size/focus position when the material to be formed is in the form of a parallel line pattern, the material is visibly masked and exposed (dry or wet). The computer's simulation results of the relationship between i and the phase shift angle. It is known from Fig. 6 that in this example, the type of phase shift mask is semi-tone (code HT), alternating (code Alt_PSM) or chrome-free (code CPL), and whether the exposure mode is dry or wet, The depth of focus is not sensitive to changes in the phase shift angle. The pattern is therefore such that the parallel line diagram of the photoresist to be formed is not suitable for reversing the phase shift angle with the depth of focus. It can be seen from Fig. 7 that the sensitivity of the critical dimension to the phase shift angle change in this example is slightly souther than the sensitivity of the focus mobility to the phase shift angle, and the bareness can be used to reverse the phase shift angle. However, as can be seen from Fig. 8, the focus position has a linear relationship with respect to the phase shift angle change, and the sensitivity is mostly at 5 nm/degree or more. Therefore, when the photoresist pattern to be formed is a parallel line pattern, it is preferable to use the focus position as a parameter of the g·reverse phase shift angle. ... Figure 9/10 shows a computer simulation of the relationship between the depth of focus/focus position* and the phase shift angle in the case where the photoresist pattern to be formed is an open array pattern and the λ mask type is a halftone phase shift mask. result. As can be seen from Fig. 9, in this case, the depth of focus hardly changes with the change of the phase shift angle, so it is not suitable to select the exposure parameter for the reverse phase shift angle. On the contrary, as can be seen from Fig. 10, in this case, the change of the focus position with the change of the phase shift angle is very obvious, so it is more suitable to select the exposure parameter which is the reverse phase shift angle. 14 1299440 17043twf.doc/g , M2 _ In the case of the photoresist pattern to be formed as an open array and the reticle type (4) chrome-free rural reticle, the computer simulation of the relationship between the phase shift angle and the phase shift angle # Λ二... The wood/to-focus structure is as shown in Fig. 5C. The part of the reticle pattern is known from Figs. 11 and 12, when the pattern is desired, and the reticle type is chrome-free two openings, the position is along with the phase shift angle. The change of change is quite awkward... The ice and water coke are the reverse phase shift angles of the exposure = the members are obvious, so both are suitable for the calibration curve of the phase shift angle test of the present invention as described above. The corresponding process can be used to reduce the phase shift angle, so that time can be saved, and the process capability characteristics such as the degree of the phase shifting mask or the focus position can be at ==:: angle & The exposure condition of the lithography process is that the k-speed shoulder is correcting the error of the phase-shift angle, so that the special= reaches the preset value to improve the correctness of the pattern transfer, and the second-= cover (four) has the phase shift angle measurement. The pattern, so the inspection angle is wide, it is necessary to measure the phase shift angle, and the inconvenience 'the same %• will not affect the product. The transfer of the body circuit_. Although the present invention is described above in terms of a touch, the present invention is defined, and any person skilled in the art and the scope of the invention may make a few exceptions: the spirit of the invention is scoped by the scope of the patent application. Protection of the Invention [Simple Description of the Drawings] Figure 11 shows a flow chart of a method for inspecting the phase shifting reticle phase shift angle of the present invention 15 1299440 17043 twf.doc/g. 2 is a flow chart showing the lithography process of the present invention. 3A and 3B illustrate two examples of phase shift masks in accordance with a preferred embodiment of the present invention, with the difference that the phase shift angle measurement patterns are placed at different positions. 4A to 4C are a top view and a cross-sectional view showing a partial structure of a phase shift angle measuring pattern on three different types of phase-shifting reticle for defining a flat pattern in a preferred embodiment of the present invention. " Fig. 5 Α exemplifies a phase shifting pattern and a cross-sectional view of a semi-transmissive reticle forming an open array pattern in the present embodiment; (4) and 5C exemplifying two chrome-free phases: The top view of the partial structure of the phase shift angle measurement pattern and the cross-sectional view/nine cover ό, 7, and 8 are shown in the case of the photoresist pattern to be formed, using different types of phase-shifting reticle and exposure, 弁When the square is in the shape of the pattern), the depth of focus/key size/poly 隹 ^ '(dry or wet brain simulation results. The relationship between the electric and the light) The second photoresist pattern is an open array pattern, and the heart is + In the case of a phase-shifting reticle, the computer simulation results of the relationship between the phase shifting and the phase shifting are shown. ",, read/focus position maps 11, 12 are shown in Fig. 11, which are intended to form = grass (four) as threats (types) , result,;; = [main component symbol description] 100~120, 200~230: step number 16 1299 burning doc/g 30: transparent substrate 300: reticle 302: integrated circuit pattern area 310: phase shift angle measurement Patterns 312, 322, 324, 332, 334, 342, 352, 354, 362, 364, 366: light transmissive regions 314, 344: semi-transmissive regions 314a, 344a: metal film
312a、322a、334a、354a、364a :溝渠 326 ·不透光區 326a :鉻金屬膜 342a :凹洞 ⑧ 17312a, 322a, 334a, 354a, 364a: trench 326 · opaque region 326a: chrome metal film 342a: recess 8 17