^ 6 6 66 4 A7 經渋部中决標本局^:工消合作社印努 B7五、發明説明（） 發明領域： 本發明係與一種半導體製程有關，特別是有關於一種 於檢測的過程中，利用改變對準圊案的形成方式，以改善 Φ合量測之方法。 發明背景： 在半導體的製程中，是以於基材上形成多層不同電性 的材質，並加以定義不同圊案的方式，以形成所需的元件 結構，來完成積體電路的製作。因此各個層所形成的位置、 形狀、及結構上的準確度及配合度，必須與前一層上的結 構有良好準確的對應，以確保元件的正確形成，達成電路 的操作性及維持產品的良率。 為了確認每一層於形成後其位置的正確性，在半導體 的製程之中，於微影製程中的顯影後檢測（afterdevelopment inspection; ADI)或钮刻製程後的姓刻後檢測（after development inspection; ΑΕΙ)過程中，會有所謂的要合量 測（overlay measurement)，針對製程中前後形成的不同層 間圖案鲞合上的正確度，進行檢測及判斷，以確保產品的 良率。 壘合量測的方法有許'多種，較常見的應用之一，即是 利用特定形狀的對準圖案的定義*來量測前後層間對準圖 案的位置相對關係，一般而言對準圖案可設置兩個、四個 (請先間讀背面之注意事項再填寫本頁) ，-° 線 本紙张尺度iU]中國扭家榡隼（CNS ) /\心見格（2I0X 297公釐） - 6 6 6 4 A7 —________B7五、發明説明（） -部中夾搰導灼兑Η消贽合作社印ί衣 或更多個不等’置於單一曝光區域的角落處或非元件區的 位置，利用每個對準圊案之前後層間的位置相對關係，即 可判斷其4合的正確度。對準圖案可有多種不同形狀的設 *十，第一 3囷顯示一種盒狀Φ合（box-in-box)的對準圊案， 前層10為一凹陷方盒’後層12為一凸起方盒，於養合量 測的過程中’可利用其高低形狀的變化量得前層丨〇及後 層12的位置，進而得到其中心點位置，再利用兩者中心 圖點位置的比對’以判斷所定義圈案疊合的正確性，第二 a圖即顯示前層1〇及後層12的結構剖面®。 第一 b圊顯示一種框狀憂合（&31116-〖11-：{>311^)的對準圖 案’凹陷框狀區域14a，或稱為空間狀（space type)區域， 代表前層14之圖案’例如圃中所顯示之方形或矩形之框 狀凸起之框狀區域16a*或稱為線狀（line type)區域， 代表將定義於後層16之圖案，同樣可為方形或矩形之框 狀區。第二b圖即顯示其結構剖面圖，凹陷框狀區域i4a 為後層16因前層14上定義之困案所造成的高度變化，因 此其代表前層14上之圊案；而凸起之框狀區域16a可為一 光阻層’因此可代表後層16於後續的蝕刻步驟中將定義 的圈案；於叠合量測的過程中，可利用其高低形狀的變化 量得凹陷框狀區域14a及凸起框狀區域16a的位置，得到 其中心位置，以判斷前層14及後層1 6所定義圖案疊合的 正破性。 第一 C囷則顯示一種條狀疊合（bar-in-bar)的對準圖 本紙张尺度適W中國國家標準（CNS ) Λ4現格（210Χ 297公釐） (請先閲讀背面之注意事項再填{本頁} TJ 11 Brnv 、νβΛ·' 6 6 6 4 A7 B7 五、發明説明（） 案，凹陷柱狀區域I8a，或稱為空間狀（spaee type)區域， 代表前層丨8之圊案，例如圖中所顯示之四個條狀區；凸 起之框狀區域20a’或稱為線狀（Hne type)區域，則代表將 定義於後層20上之图案，同樣可為四個條狀區β第二。圖 即顯示其結構刮面圖，可利用其高低形狀的變化量得凹陷 柱狀區域18a及凸起柱狀區域2〇a的位置，得到其中心位 置’而判斷前層18及後層20所定義圖案φ合的正確性。 在傳統元件尺寸較大的製程之+，上述的框狀疊合或 柱狀4合的對準圖案可於檢測的過程中具有良好的位置顯 示及判斷效果，但是隨著積集度的提高及元件尺寸的縮 小，在目前次微米及未來尺寸更小的製程技術中，上述對 準圖案中凹陷區域的形成，如第二b圖中的凹陷區域i4b 或第二c圖中的凹陷區域18b’往往會由於如姓刻或化學 機械研磨（chemical-mechanical polishing)或鍍膜 16 時等製 程的影孪，產生形狀上的變化或扭曲，而造成疊合量測時 的誤差或判斷錯誤等。 以下即g平坦化製程中形成對準圖案的過程做一介 紹’參見第三圓所示’半導體基材30上之氧化層或前層32 包含一凹陷區域’並有第一金屬層34形成於其上，用以填 入於凹陷區域之内，第一金屬層34、或稱為栓金屬（piUg metal)層通常使用鎢（W)或其他金屬，凹陷區域即為第二b 囷中的凹陷區域14b或第二c圊中的凹陷區域18b，因此 其形狀的完整性對於壘合量測時的判斷極為重要。 本紙乐尺度適用中國囡窣榡嗥（C，NS ) Λ4規格（210x 297公釐） (#先閱讀背面之注項再填艿本頁) ♦^ 6 6 66 4 A7 Specimen Bureau in the Ministry of Economic Affairs ^: Industrial Consumers Cooperatives Innu B7 V. Description of the invention () Field of the invention: The present invention relates to a semiconductor process, especially to a process in the detection, The method of changing the alignment pattern is used to improve the method of measuring the Φ combination. Background of the Invention: In the semiconductor manufacturing process, the fabrication of integrated circuits is completed by forming multiple layers of different electrical materials on a substrate and defining different schemes to form the required element structure. Therefore, the position, shape, and structural accuracy and coordination of each layer must correspond well with the structure on the previous layer to ensure the correct formation of components, achieve circuit operability, and maintain good product quality. rate. In order to confirm the correctness of the position of each layer after it is formed, during the semiconductor manufacturing process, after development inspection (ADI) in the lithography process or after the last name inspection after the button etching process; In the process of AEI, there is a so-called overlay measurement, which detects and judges the correctness of the combination of different interlayer patterns formed before and after in the process to ensure the yield of the product. There are many kinds of barrier measurement methods. One of the more common applications is to use the definition of a specific shape of the alignment pattern * to measure the positional relationship between the alignment patterns before and after the layer. Generally speaking, the alignment patterns can be Set two or four (please read the notes on the back first and then fill in this page),-° Thread paper size iU] China Twist House (CNS) / \ 心 见 格 (2I0X 297 mm)-6 6 6 4 A7 — ________B7 V. Description of the invention ()-In the ministry, the guides are burned, the cooperatives are printed, or the clothes are printed on the corner of a single exposure area or a non-component area. The positional relationship between the layers before and after each alignment case can determine the correctness of the quadruple. The alignment pattern can have a variety of different shapes. The first 3 frames show a box-in-box alignment scheme. The front layer 10 is a recessed box. The rear layer 12 is a The raised square box can be used to determine the position of the front layer 丨 0 and the rear layer 12 by using the amount of its height change during the measurement of nutrient measurement, and then obtain the center point position. Compare 'to determine the correctness of the defined circle stacking. Figure 2a shows the structural section of the front layer 10 and the rear layer 12. The first b 圊 shows a frame-like alignment (& 31116- 〖11-: {> 311 ^) alignment pattern 'recessed frame-like region 14a, or a space-type region, representing the front layer The pattern of 14 ', such as the square or rectangular frame-like raised frame-shaped area 16a * shown in the garden, or the line type area, represents the pattern to be defined in the back layer 16, and can also be square or A rectangular frame-like area. Figure 2b shows the structural cross-section. The recessed frame-shaped area i4a is the height change of the rear layer 16 caused by the dilemma defined on the front layer 14. Therefore, it represents the case on the front layer 14; The frame-shaped region 16a may be a photoresist layer, and thus may represent a circle defined by the subsequent layer 16 in a subsequent etching step; in the process of superposition measurement, a change in shape of the height may be used to obtain a recessed frame-like shape. The positions of the region 14a and the raised frame-shaped region 16a are obtained at their center positions to determine the normal breakability of the superimposed patterns defined by the front layer 14 and the rear layer 16. The first C 囷 shows a bar-in-bar alignment chart. The paper size is suitable for China National Standards (CNS). Λ4 is present (210 × 297 mm). (Please read the precautions on the back first. Fill in {this page} TJ 11 Brnv, νβΛ · '6 6 6 4 A7 B7 V. Description of the invention () proposal, the recessed columnar area I8a, or the space (spaee type) area, represents the front layer Cases, such as the four strip-shaped areas shown in the figure; the raised frame-shaped area 20a ', or the Hne type area, represents the pattern to be defined on the back layer 20, which can also be four Each strip-shaped area β is second. The figure shows the structure scraping surface, and the position of the concave columnar area 18a and the convex columnar area 20a can be obtained by using the change of its height shape to determine its center position. The correctness of the pattern φ defined by the front layer 18 and the back layer 20. In the process of the larger traditional component size +, the above-mentioned frame-shaped stack or column-shaped quadruple alignment pattern can have a good quality during the inspection process. Position display and judgment effect, but with the increase of the accumulation degree and the reduction of component size, In the process technology of smaller meters and future sizes, the formation of recessed areas in the above alignment patterns, such as the recessed area i4b in the second b figure or the recessed area 18b 'in the second c figure, is often caused by In the process of chemical-mechanical polishing or coating at 16 hours, the shape change or distortion may occur, which may cause errors or misjudgments in the overlay measurement. The following is the formation of alignment during the g-flattening process. The process of the pattern is described 'see the third circle', the oxide layer or front layer 32 on the semiconductor substrate 30 contains a recessed area 'and a first metal layer 34 is formed thereon to fill the recessed area Within the first metal layer 34, or piUg metal layer, tungsten (W) or other metal is usually used, and the recessed area is the recessed area 14b in the second b 囷 or the recess in the second c 圊Area 18b, so the integrity of its shape is extremely important for judging the barrier measurement. This paper music scale is applicable to China 囡 窣 榡 嗥 (C, NS) Λ4 size (210x 297 mm) (#First read the note on the back (Refill this page) ♦
Λ'發明説明（) 之後進行一平坦化製程以去除表面部分之第一金屬層 34，平垣化製程可使用回蝕製程或是金屬之化學機械研磨 數程，當使用回蝕製程後’會如第四a圈所示’留下一側 受結構3 4b。參見第五a圊所示’於回蝕製程後’再鍍上 第二金屬層36(即後層）於氣化屠32及检金屑層之側壁結 構3 4b之上，通常第二金屬層36是使用鋁銅、銘矽銅、鋁 或其他金屬等，且第二金屬層36沈積時會於四陷區域的尖 角處堆積較多的材質，亦容易產生如圖中所示略有不對稱 的情形，而在凹陷區域中央的上方則會由於沈積配合表面 的形狀變化而留下一個開口較小的狹縫3 7。 參見第六a圖所示，接著形成並定義光阻層38，由於 光阻層38形成時對狹缝37較佳的填入特性，加上狹缝37 的開口較小，會於定義光阻層38後留下一難以去除的光阻 材質38b於狹缝37内，而在綦合量測的過程中，董測方式 係由上方以光學量測的方式進行’彳a由於第二金属層36在 尖角處附近堆積較多，高度變化較為平缓，加上光阻材質 38b的影蜜：會使感測所得的高度變化訊號較不明顯，造 成判斷的不易，甚至產生位I上的偏盖。 而在另一例中使用金厲之化學機械研磨製程時’會由 於凹陷區域附近去除較快，而導致凹陷區域邊緣的軋化層Λ'Explanation of the invention () After that, a planarization process is performed to remove the first metal layer 34 on the surface portion. The flat-granularization process can use an etch-back process or a chemical mechanical polishing process of the metal. When the etch-back process is used, it will be like The fourth circle a is shown 'Leave side affected by structure 3 4b. Refer to the fifth a) shown in “after the etch-back process” and then plate a second metal layer 36 (that is, the back layer) on the sidewall structure 3 4b of the gasification tank 32 and the gold detection layer, usually the second metal layer 36 is a material that uses aluminum copper, silicon copper, aluminum, or other metals, and the second metal layer 36 is deposited at the sharp corners of the four recessed areas when it is deposited, and it is also easy to produce a slight difference as shown in the figure. Symmetrical situation, but above the center of the recessed area, a small opening 37 is left due to the shape change of the deposition mating surface. Referring to FIG. 6a, the photoresist layer 38 is then formed and defined. Due to the better filling characteristics of the slit 37 when the photoresist layer 38 is formed, plus the small opening of the slit 37, it will define the photoresist. A hard-to-remove photoresist material 38b is left behind the layer 38 in the slit 37, and in the process of coupling measurement, the measurement method is performed optically from the top. '彳 a Because the second metal layer 36 is in the There is more accumulation near the sharp corners, and the height change is relatively gentle. Adding the shadow honey of photoresist material 38b: it will make the height change signal obtained by sensing less obvious, which will make it difficult to judge, and even produce a partial cover on bit I. In another example, when using Jinli's CMP process, it ’s removed quickly near the recessed area, resulting in a rolled layer at the edge of the recessed area.
In 被去除一部分，而形成如第四b囷所示的形狀，留下一 部分的拴金屑層34c。參見第五b圖所示，於化學機械研 磨製程後’再鍍上第二金眉層40(即後層）於氧化層32及 本紙張尺度適川中國同家標準（CNs )以規格（.2|〇Χ 297公釐） (請先閲請背面之注意事項再填窍本S ) 訂 ------0 i. 經^部中欢梂涞灼只^消资合作衫印梦 B7五、發明説明（） 栓金屬層34c之上，由於凹陷區域邊緣的氧化層32被去除 一部分，第二金屬層40形成後其表面的高度變化較平緩， 亦可能因第二金屬層40沈積時的不均勻性產生如圖中所示 略有不對稱的情形，並同樣在凹陷區域中央的上方留下一 狹缝42。 參見第六b圖所示，接著形成並定義光阻層44，由於 光阻層44形成時對狭縫42較佳的填入特性，會於定義光 阻層44後留下一難以去除的光阻材質44b，而在疊合量測 的過程中，由於第二金屬層40在部分氡化層32被去除的 狀況下，高度變化較不明顯，加上光阻材質 44b的影響， 會使感測所得的高度變化訊號較弱，因此可能形成所量得 的對準圖案有扭曲變形。在金屬化學機械研磨製程中，研 磨劑和栓金屬化學反應之副產物，如氡化鎢等，會填充在 狹縫中，而使狹縫被填平，而形成如第七圖中所示的斷線 區域46。造成判斷的不易及位置上的誤差，使疊合量測確 認圖案位置正確度的目的無法達成，對產品良率的檢測及 控制形成不氐的影響。 A7 ------*---=-‘<*------訂 — ------線 (诗先閱讀背面之注意事項再填寫本頁) 本紙張尺度通用中国®家標準（CNS)八4現格（2!〇χ 297公釐） A7 B7五、發明説明（） 發明目的及概述： 本發明的目的為提供一種改善疊合量測之方法。 本發明的目的為提供一種形成對準圖案之方法，可提 昇疊合量測的易判性及正確度。 本發明的另一目的為提供一種改善疊合量測之方法， 以增進製程後檢測的判斷性及提昇對良率的控制性。 本發明中形成對準圖案以改善疊合量測之方法，可包 含以下步驟：首先形成一前層於一半導體基材上；並於前 層内定義一凹陷區域，凹陷區域内包含至少一個柱狀區， 至少一個柱狀區將凹陷區域分隔為至少兩個次凹陷區：再 形成一第一後層於前層上；接著進行一平坦化製程，以去 除凹陷區域以外之第一後層；之後形成一第二後層於前層 及第一後層上。 本發明十之方法並可進一步於上述之第二後層形成 後，進行以下步驟：形成一光阻層於第二後層上；並定義 光阻層以形$對準圖案之線狀區域，最後再進行叠合量測。 圈式簡箪說明： 第一 a圖顯示傳統之盒狀疊合對準圖案的上視示意 圖。 第一 b圖顯示傳統之框狀疊合對準圊案的上視示意 圖。 {請先閲請背面之注意事項再填1'1;本頁) 線丨—Λ. 本紙&尺度適州十國围家標卑（（:NS ) Λ4規格ί 2!Ox297公釐） 經潢部中夾讶龙灼W.T..消价合作社印¥ ^ ^ ^ G 6 4 - J A7 ' B7五、發明説明（） 第一 C圖顯示傳統之條狀疊合對準圖案的上視示意 圖。 第二a圖顯示傳統之盒狀疊合對準圖案結構的剖面示 意圊。 第二b圖顯示傳統之框狀疊合對準圊案結構的剖面示 意圖。 第二c圊顯示傳統之條狀疊合對準圖案結構的剖面示 意圖。 第三圖顯示金屬化製程中一半導體基材上之氧化層及 栓金屬層在大尺寸的凹陷區的剖面示意圖。 第四a圖顯示金屬化製程中使用回蝕製程後之基材的 剖面示意圖。 第四b圊顯示金屬化製程中使用金屬化學機械研磨製 程後之基材的剖面示意圖。 第五a圖顯示金屬化製程中於回蝕製程後形成第二金 屬層的剖面示意圖。 第五b圖顯示金屬化製程中於金屬化學機械研磨製程 後形成第二金屬層的剖面示意圖。 第六a圖顯示金屬化製程t使用回蝕製程之例子t， 形成並定義光阻層後的剖面示意圊。 第六b圖顯示金屬化，製程中使用金屬化學機械研磨製 程之例子中，形成並定義光阻層後的刟面示意圊。 第七圊顯示金屬化製程中之對準圊案有扭曲變形及部 ------.--------訂------線---- (請先聞讀背面之注意^項再填筠本頁) 本尺度適坩屮囡囤家標4*- ( CNS ) Λ4規格（210Χ297公釐） 4 6 6 66 4 A7 B7 五、發明説明（） 分區域無法感測的上視示意圖。 第八圖顯示本發明中於基材上形成前層及第一後層的 剖面示意圊。 第九a圖顯示本發明中使用回蝕製程後之基材的剖面 示意圖。 第九b圖顯示本發明中使用金屬化學機械研磨製程後 之基材的剖面示意圊。 第十 a圊顯示本發明中於回蝕製程後，形成第二後層 的剖面示意圖。 第十b圊顯示本發明中於化學機械研磨製程後，形成 第二後層的剖面示意圖。 第十一 a圖顯示本發明中使用回蝕製程之例子中，形 成並定義光阻層後的剖面示意圖。 第十一 b圖顯示本發明中使用化學機械研磨製程之例 子中，形成並定義光阻層後的剖面示意困。 第十二圖顯示本發明中之對準®案可完整被感測出的 上視示意圖' 發明詳細說明： 本發明中提供一種改善疊合量測之方法，利用改變形 成對準圊案之方法，於對準圖案的前層内定義一凹陷區 域，並使凹陷區域内包含一個或多個的柱狀區，可消除傳 統製程中平坦化製程中部分的前層被去除的效應，以提昇 本紙悵尺度適川中国囚家標準（CNS ) A4«L格（210Χ297公釐） ^^ϋ·— 1^1^1 ^^1 (請先閱讀背面之注意事項再填荇本頁)A portion of In is removed to form a shape as shown in the fourth b 囷, leaving a portion of the gold shavings layer 34c. See Figure 5b, after the chemical mechanical polishing process, a second gold eyebrow layer 40 (ie, the rear layer) is plated on the oxide layer 32 and the paper size is in accordance with the Chinese standards (CNs) of Sichuan. 2 | 〇Χ 297 mm) (Please read the notes on the back, and then fill in this book S) Order ------ 0 i. The ^ Department of Huan Huan Zhuo only ^ Consumption Cooperation Shirt Printing Dream B7 V. Description of the invention () Above the plug metal layer 34c, since the oxide layer 32 at the edge of the recessed area is partially removed, the height change of the surface of the second metal layer 40 after the formation is relatively gentle, and it may also be caused when the second metal layer 40 is deposited. The non-uniformity of the sintering causes a slight asymmetry as shown in the figure, and also leaves a slit 42 above the center of the recessed area. Referring to FIG. 6b, the photoresist layer 44 is then formed and defined. Due to the better filling characteristics of the slits 42 when the photoresist layer 44 is formed, a difficult-to-remove light will be left after the photoresist layer 44 is defined. Resist material 44b, and during the overlay measurement process, the height of the second metal layer 40 is less noticeable when part of the halide layer 32 is removed, and the effect of the photoresist material 44b will make the sensor The measured height change signal is weak, so the measured alignment pattern may be distorted. In the metal chemical mechanical polishing process, the by-products of the chemical reaction between the abrasive and the plug metal, such as tungsten hafnium, etc., will be filled in the slits, and the slits will be filled to form the same as shown in the seventh figure. Disconnected area 46. As a result, it is difficult to judge and the position error makes the purpose of superimposed measurement to confirm the correctness of the pattern position unable to be achieved, which has a great impact on the detection and control of product yield. A7 ------ * --- =-'< * ------ Order-- ------ line (read the notes on the back of the poem before filling in this page) This paper size is common in China ® Home Standard (CNS) 8 4 (2! 〇χ 297 mm) A7 B7 V. Description of the invention () Purpose and summary of the invention: The purpose of the present invention is to provide a method for improving superposition measurement. An object of the present invention is to provide a method for forming an alignment pattern, which can improve the easiness and accuracy of superposition measurement. Another object of the present invention is to provide a method for improving the overlap measurement, so as to improve the judgment of the post-process detection and the control of the yield. The method for forming an alignment pattern in the present invention to improve the overlay measurement may include the following steps: first forming a front layer on a semiconductor substrate; and defining a recessed area in the front layer, the recessed area including at least one pillar At least one columnar area divides the recessed area into at least two sub-recessed areas: forming a first back layer on the front layer; and then performing a planarization process to remove the first back layer outside the recessed area; A second back layer is then formed on the front layer and the first back layer. According to the method of the present invention, after the second back layer is formed, the following steps may be performed: forming a photoresist layer on the second back layer; and defining a linear region of the photoresist layer in a shape of an alignment pattern, Finally, overlap measurement is performed. Brief description of the circle type: The first figure a shows a schematic top view of a conventional box-shaped superimposed alignment pattern. Figure 1b shows a schematic top view of a conventional frame-shaped superimposed alignment scheme. {Please read the notes on the back first and then fill in 1'1; this page) Line 丨 —Λ. This paper & scale Shizhou Shiguo Wai Jiabiao ((: NS) Λ4 size ί 2! Ox297 mm) Warp The decoration department is surprised by the scorching dragon WT. Consumption cooperative printing ¥ ^ ^ ^ G 6 4-J A7 'B7 V. Description of the invention () Figure C shows the top view of the traditional strip-shaped superimposed alignment pattern. Figure 2a shows a schematic cross-sectional view of a conventional box-shaped superimposed alignment pattern structure. Figure 2b shows a schematic cross-sectional view of a conventional frame-shaped superimposed alignment structure. The second c) shows a cross-sectional view of a conventional strip-shaped superimposed alignment pattern structure. The third figure shows a schematic cross-sectional view of an oxide layer and a plug metal layer on a semiconductor substrate in a large-sized recessed area during a metallization process. Figure 4a shows a schematic cross-sectional view of the substrate after the etch-back process is used in the metallization process. The fourth b) shows a schematic cross-sectional view of the substrate after the metal chemical mechanical polishing process is used in the metallization process. Figure 5a shows a schematic cross-sectional view of the second metal layer formed after the etch-back process in the metallization process. Figure 5b shows a schematic cross-sectional view of the second metal layer formed after the metal chemical mechanical polishing process in the metallization process. Fig. 6a shows an example t using an etch-back process for the metallization process t, and a schematic cross-section after forming and defining a photoresist layer. Figure 6b shows metallization. In the example of the metal chemical mechanical polishing process used in the manufacturing process, the schematic surface of the photoresist layer is formed and defined. Seventh: It shows that the alignment in the metallization process has distortion and deformation .---------------- Order ------ line ---- (Please read and read first Note on the back ^ item and refill this page) This standard is suitable for housekeeping 4 *-(CNS) Λ4 specification (210 × 297 mm) 4 6 6 66 4 A7 B7 V. Description of the invention Measured top view diagram. The eighth figure shows a schematic cross-section of a front layer and a first rear layer formed on a substrate in the present invention. Figure 9a shows a schematic cross-sectional view of the substrate after the etch-back process is used in the present invention. Figure 9b shows a schematic cross-section of the substrate after the metal chemical mechanical polishing process is used in the present invention. The tenth a) shows a schematic cross-sectional view of forming a second back layer after the etch-back process in the present invention. The tenth b) is a schematic cross-sectional view of forming a second back layer after the CMP process in the present invention. Fig. 11a is a schematic cross-sectional view of an example using an etch-back process in the present invention after forming and defining a photoresist layer. Figure 11b shows an example of a chemical mechanical polishing process used in the present invention. The cross section after the photoresist layer is formed and defined is schematically shown. The twelfth figure shows a schematic diagram of the top view of the alignment® solution in the present invention that can be completely sensed. 'Detailed description of the invention: The present invention provides a method for improving the overlay measurement, and the method of changing the alignment pattern is formed. , Define a recessed area in the front layer of the alignment pattern, and make the recessed area contain one or more columnar areas, which can eliminate the effect of removing the front layer in the flattening process in the traditional process to improve the paper怅 Suitable Chinese Standard for Prisoners in China (CNS) A4 «L (210 × 297 mm) ^^ ϋ · — 1 ^ 1 ^ 1 ^^ 1 (Please read the precautions on the back before filling this page)
.1T Α7 Β7 ύ'6 4 五、發明説明（） 疊合量測的易判性及正確度。 在不限制本發明之精神及應用範圍下’以下以一金屬 層形成於氧化層上後，所需形成的對準围案及其後的曼合 量測為例，介紹本發明之實施，而熟知此領域技藝者，於 了解本發明之精神後，當可運用相同之方法’應用於各種 不同的前層及後層的材質上’其使用範園不僅限於以下之 實施例。 參見第八圖所示，首先形成一前層52於一半導體基 材50上，前層52可為一氧化層’並可籍由化學氣相沈積 的方式加以形成，接著於前層52内定義一凹陷區域52a’ 凹陷區域52a内包含一個或多個的柱狀區52b ’柱狀區52b 將凹陷區域52a分隔為多個次凹陷區52c。柱狀區52b的 形成方式，可利用定義凹陷區域52a時’同時定義相等於 柱狀區5 2b宽度的罩幕區或光阻區於前層52上’並利用蝕 刻製程去除部分之前層52以保留柱狀區5 2b及形成次凹陷 區5 2c。在本實施例中使用兩個柱狀區52b，因而分隔出三 個次凹陷區$ 2c，柱狀區5 2b及次凹陷區52c的寬度’可 控制在約1微米以下，本例中所使用的寬度約在〇. 4微米 至0.8微米之間》 接著形成一第一後層54於前層52之上，如第八圖所 示，第一後層54係用以填入次凹陷區5 2c較窄的區域中， 以防止因後續層的復蓋性不佳而於次凹陷區52c形成孔 洞；因此第一後層54可使用填入性或復蓋性較佳的材質， 本紙張尺度適州中國IS家標隼（C’NS ) Λ4坭格U10X 297公釐）.1T Α7 Β7 ύ'6 4 V. Description of the invention () The judging and correctness of superposition measurement. Without limiting the spirit and application scope of the present invention, the following describes the implementation of the present invention with an alignment case and subsequent measurement of the amount of the metal layer to be formed after it is formed on the oxide layer, and Those skilled in the art, after understanding the spirit of the present invention, can use the same method to 'apply to different materials of the front layer and the back layer', and its use range is not limited to the following embodiments. Referring to FIG. 8, a front layer 52 is first formed on a semiconductor substrate 50. The front layer 52 may be an oxide layer and may be formed by chemical vapor deposition, and then defined in the front layer 52. A recessed region 52a 'includes one or more columnar regions 52b' in the recessed region 52a. The columnar region 52b divides the recessed region 52a into a plurality of secondary recessed regions 52c. The formation of the columnar region 52b can be defined by defining the recessed region 52a 'at the same time as the mask region or photoresistive region on the front layer 52 which is equal to the width of the columnar region 5 2b' and using an etching process to remove part of the previous layer 52 to The columnar region 5 2b and the sub-recessed region 5 2c remain. In this embodiment, two columnar regions 52b are used, so three sub-recessed regions $ 2c are separated. The width 'of the columnar region 5 2b and the sub-recessed region 52c can be controlled below about 1 micron, which is used in this example. The width is about 0.4 micrometers to 0.8 micrometers. Then a first back layer 54 is formed on the front layer 52. As shown in the eighth figure, the first back layer 54 is used to fill the sub-depression area 5 In the narrower area 2c, to prevent the formation of holes in the sub-recessed area 52c due to the poor coverage of the subsequent layer; therefore, the first back layer 54 can use a material with better filling or covering properties. Shizhou China IS House Mark (C'NS) Λ4 坭 Grid U10X 297 mm)
(諳先聞讀背面之注意事項再填寫本頁J $ 、-=* A7 4 6 6 6 6 B7 五、發明説明（） 本例中係使用鎢做為第一後層5 4，並可以濺鍍或化學氣相 沈積的方式以形成鎢層，並完全填入於次凹陷區52c之中。 之後進行一平坦化製程，以去除凹陷區域 52a以外的 第一後層 54，平坦化製程可使用一回蝕製程或是化學機械 研磨製程；參見第九a圖所示，即為使用回蝕製程做為平 坦化製程，完成平坦化後的示意圖，留下部分的第一後層 54於次凹陷區52c之中，並於次凹陷區52c上方產生微小 的凹陷區56 。 參見第十a圈所示，接著形成一第二後層58於前層52 及第一後層54上，第二後層58可使用一鋁銅層，並以濺 鍍的方式加以形成，由於凹陷區56的凹陷形狀完整，且落 差不會太大，第二後層58形成後其表面即可複製保持原有 之表面拓樸結構，而不會有傳統製程中因凹陷區尖角上第 二後層5 8沈積不對稱、或是邊緣不夠尖銳，而造成的檢測 不準的缺點。 接著並形成一光阻層60於第二後層58上，並定義光 阻層60以形或對準圖案之線狀區域，如第十一 a圖所示， 以定義蝕刻第二後層5 8之圊案，之後即可進行疊合量測。 參見第九b圖所示，即為使用金屬化學機械研磨製程 做為平坦化製程，完成平坦化後的示意圖，留下部分的第 一後層54於次凹陷區52c之中，由於化學機械研磨製程對 有凹陷區域部分會研磨較多的特性，柱狀區 52b的表面亦 會被去除一部分，但第一後層54由於其形成時即有表面的 本紙烺尺度適川中國囚家標4M CNS ) Λ4現格（2I0X297公釐） ------—,---------ir------^ (請先閱讀背面之注意事項再填巧本頁) 妊# 部+^^^.^--^^¾^^^^^¾ 4 6 6 6 6 明（） 凹陷’因此於研磨後其高度會較柱狀區52b略低，形成如 圖中所杀的多個微小凹陷62。 參見第十b圈所示’接著形成一第二後層64於前層52 及第一後層54上’第二後層64同樣使用鋁銅層，並以滅 鍵的方式形成’由於凹陷區62的凹陷形狀完整，且落差不 會太大，第二後層64形成後其表面即可保持原有之表面拓 棋結構’而不會有傳統製程中因表面邊緣變化平緩，或因 第二後層沈積不對稱、邊緣不夠尖銳、或因研磨殘餘物填 平凹陷區，而造成的檢測不準的缺點》 第二後層64形成後其表面即可具有較明顯的落差變 化，而不會有傳統製程中因表面變化平緩而造成的檢測不 易的缺點。 接著並形成一光阻層66於第二後層64上，並定義光 阻層66以形成對準圊案之線狀區域，如第十_ b圖所示， 以定義蝕刻第二後層58之圖案，之後即可進行要合量測。 因此不論是第十一 a围中採用回蝕製程，或是如第十 一 b圈中採用化學機械研磨製程後的結果，利用本發明於 凹陷區52a中加入柱狀區52b的方法，岣可得到最後於第 二後層58表面處能保持原有的表面拓樸結構，而不會有 傳統製程的缺點，於*合量測時，即可得到較佳的訊號， 如第十二圖所示’可取得明確而易於判斷的訊號，而得到 具有完整形狀的對準圈案’消除如第七圏中對準固案變形 扭曲斷線的缺點，並且不會有光阻材質殘留於狹縫中的缺 本紙伕尺度適用中國囚家標隼（CNS ) Λ4規格（21〇><297公釐> ---------Γ^------訂------線 (請先閱讀背面之注意事項再填筠本頁) 6 66 4 A7 . B7 五、發明说明（） 點，因此即可得到正確的前後層間之相對位置，提再疊合 量測的正確度。 本發明以一較佳實施例說明如上，僅用於藉以幫助了 解本發明之實施，非用以限定本發明之精神，而熟悉此領 域技藝者於領悟本發明之精神後，在不脫離本發明之精神 範圍内，當可作些許更動潤飾及等同之變化替換，其專利 保護範圍當視後附之申請專利範圍及其等同領域而定。 . . 1 种农II 1 1 , 訂 染 (請先閱讀背面之注意事項再填窍本頁) Μ","ψ•决""^π-1··1·-"'1贤合竹 本紙張尺度適用中國Η家椋4M ('NS ) Λ4規格（210X297公釐）(谙 First read the notes on the back and fill in this page J $ 、-= * A7 4 6 6 6 6 B7 V. Description of the invention () In this example, tungsten is used as the first back layer 5 4 and can be splashed The tungsten layer is formed by plating or chemical vapor deposition, and is completely filled in the sub-recessed area 52c. Then a planarization process is performed to remove the first back layer 54 outside the recessed area 52a. The planarization process can be used An etch-back process or a chemical mechanical polishing process; see Figure 9a, which is a schematic diagram of the planarization after using the etch-back process as a planarization process, leaving a portion of the first back layer 54 in the second depression In the area 52c, a minute recessed area 56 is generated above the sub-recessed area 52c. Referring to the tenth circle a, a second rear layer 58 is then formed on the front layer 52 and the first rear layer 54, and the second rear The layer 58 can be formed by an aluminum copper layer and formed by sputtering. Since the recess shape of the recessed area 56 is complete and the drop is not too large, the surface of the second back layer 58 can be copied to maintain the original Topological structure on the surface, without the sharp corner of the recessed area in the traditional process The back layer 58 has the disadvantage of being asymmetrically deposited or the edges are not sharp enough, resulting in inaccurate detection. Next, a photoresist layer 60 is formed on the second back layer 58 and the photoresist layer 60 is defined in shape or alignment. The linear area of the pattern, as shown in Figure 11a, is used to define the scheme of etching the second back layer 58, and then the overlay measurement can be performed. See Figure 9b, which uses metal chemistry The mechanical polishing process is used as a planarization process. After the planarization is completed, a part of the first rear layer 54 is left in the sub-recessed area 52c. Due to the characteristics of the chemical mechanical polishing process, the recessed area will be ground more. Part of the surface of the columnar region 52b will also be removed, but the first back layer 54 has a surface of the original paper when it was formed. The scale is suitable for the Chinese prison house standard 4M CNS) Λ4 (2I0X297 mm) ---- ---, --------- ir ------ ^ (Please read the precautions on the back before filling out this page) Pregnancy # 部 + ^^^. ^-^^ ¾ ^ ^^^^ ¾ 4 6 6 6 6 Therefore, after grinding, its height will be slightly lower than the columnar area 52b, forming a plurality of tiny depressions 62 as shown in the figure. See the tenth circle b. 'Next, a second back layer 64 is formed on the front layer 52 and the first back layer 54.' The second back layer 64 also uses an aluminum copper layer, and is formed in a debonding manner. The shape of the depression of 62 is complete, and the drop will not be too large. After the second back layer 64 is formed, the surface can maintain the original surface topology structure. Disadvantages of back layer deposition asymmetry, insufficiently sharp edges, or inaccurate detection caused by grinding residue filling up the recessed area "After the formation of the second back layer 64, the surface can have a noticeable drop change without It has the disadvantage that it is not easy to detect due to the smooth surface change in the traditional process. Next, a photoresist layer 66 is formed on the second back layer 64, and the photoresist layer 66 is defined to form a linear region aligned with the pattern, as shown in Fig. 10b, to define the etching of the second back layer 58 The pattern can be measured afterwards. Therefore, no matter whether the etch-back process is used in the eleventh circle or the result of the chemical mechanical polishing process in the eleventh circle, the method of adding the columnar region 52b to the recessed region 52a can be used. It is finally obtained that the original surface topology structure can be maintained at the surface of the second rear layer 58 without the disadvantages of the traditional process. When the combined measurement is performed, a better signal can be obtained, as shown in Figure 12 Show 'can obtain a clear and easy to judge signal, and get a complete alignment ring case' eliminates the shortcomings such as distortion and twisting of the alignment solid case in the seventh line, and no photoresist material remains in the slit Standards for missing papers in China are applicable to Chinese Prisoners' Standards (CNS) Λ4 specification (21〇 > < 297mm > --------- Γ ^ ------ Order --- --- Line (please read the precautions on the back before filling this page) 6 66 4 A7. B7 V. Description of the invention () point, so you can get the correct relative position between the front and back layers, and then superimpose the measurement The accuracy of the present invention is described above with a preferred embodiment, which is only used to help understand the implementation of the present invention, not intended to The spirit of the present invention is determined, and those skilled in the art who understand the spirit of the present invention can make minor modifications and equivalent changes without departing from the spirit of the present invention. The scope of patent protection shall be attached as follows. The scope of patent application and its equivalent field depends on... 1 type of agricultural II 1 1, ordering (please read the precautions on the back before filling out this page) Μ ", " ψ • 定 " " ^ π- 1 ·· 1 ·-" '1 Xianhe Bamboo Paper Size Applicable to ChinaΗ 家 Η4M (' NS) Λ4 Specification (210X297mm)