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doc/OOS A7 B7 五、發明說明（：） 本發明是有關於一種檢測對準偏差的方法，且特別是 有關於一種以具有圓弧的標示來檢測進行曝光步驟時之對 準偏差的方法。 在積體電路的製程中，常以曝光的方式將光罩上的圖 案轉移至光阻層，以於晶圓上定義圖案。當積體電路的積 集度不斷提昇，在對光阻層進行曝光的步驟時，晶圓對準 的精確度也就顯得相當重要。 習知在曝光步驟中決定晶圓之位置的方法，是在晶圓 上先形成曝光對準標7K(Alignment Mark)。在進行光阻層 曝光的步驟時’就以曝光對準標示對準光罩的特定圖案， 以使光罩上的圖案轉移到晶圓上的正確位置。但是這樣的 對準方式仍然可能因爲解析度的限制而有一些誤差，當積 體電路的製程進入深次微米的程度時，這樣的誤差將嚴重 的影響到晶圓的品質。 爲了減小曝光步驟時所產生的對準偏差對製程良率的 影響，目前的製程步驟都是在一批次(通常爲25片）的晶圓 中，先以一片晶圓進行曝光的步驟，在晶圓上一些特定的 點量測其對準偏差。之後，再根據晶圓上之不同點所量測 出之對準偏差，計算出同一批次之其他晶圓在進行曝光步 驟時所需的修正量。 第1A圖繪示習知一種用以檢測曝光對準偏差之結構 的上視圖。 請參照第1A圖，在晶圓1〇〇上具有曝光對準標示102 與外層標示1〇4’外層標示1〇4在晶圓1〇〇上排列成方形。 3 本紙張尺度適用辛國國家標準（CNS)A4規格（2〗〇χ 297公釐） (請先閱讀背面之注意事項再填寫本頁) — 裝 經濟部智慧財產局員工消費合作社印製 α 經濟部智慧財產局員工消費合作社印製 Λ7 B7 五、發明說明（v ) 其中，外層標示1〇4是由四個溝渠104a、104b、104c以 及104d所構成。內層標示106的材質爲光阻，其形成方 法是在晶圓100上形成光阻層（未繪示於圖中）之後’藉由 以曝光對準標示102對準光罩（未繪示於圖中）上之特定圖 案的方式來確定晶圓100的位置，再進行光阻層曝光以及 顯影的步驟，以於晶圓100上形成方形的內層標示106。 經過曝光對準標示102的對準，內層標示106大致上位於 外層標示104所排列的方形中。其中，內層標示106是由 四個條形結構106a、l〇6b、l〇6c與106d所構成。 內層標示106原本是預定形成於外層標示104的正中 央，而且內層標示106的每一邊都與外層標示104的對應 邊互相平行並保持相同的距離。但是，當曝光的步驟有對 準偏差時’內層標不1〇6就會偏離外層標示104的正中央。 其偏離的程度即爲晶圓100在此區域的對準偏差。 爲了淸楚的說明習知檢測對準偏差的方法，以下將第 1A圖中的水平方向定義爲X軸，並將第1A圖中的垂直方 向定義爲Y軸。習知檢測對準偏差的方法是選定平行於X 軸的第一測量線108 ’其中第一測量線108與外層標示104 的凹槽104a與104c分別交會於A,與A4。第一測量線1〇8 並且與內層標示1〇6的條狀結構l〇6a與i〇6c分別交會於 A2與A3。其中’ A,的X座標爲Xl，a2的X座標爲χ2， Α3的X座標爲x3 ’ Α4的座標爲Χ4。而Χι和χ4之平均値 與x2和x3之平均値的差異’即爲曝光步驟在X方向上所 造成的對準偏差。 4 (請先閱讀背面之注意事項再填寫本頁) * --------訂-------—% 本紙張尺度適用中國國家標準<CNS)A4規格<210x297公釐） 269 2*7 k w 4 6 S h、，ί·doc / OOS A7 B7 V. Description of the invention (:) The present invention relates to a method for detecting misalignment, and more particularly to a method for detecting the misalignment when performing an exposure step with a mark having an arc. In the integrated circuit manufacturing process, the pattern on the photomask is often transferred to the photoresist layer by exposure to define the pattern on the wafer. As the integration of integrated circuits continues to increase, the accuracy of wafer alignment becomes very important during the step of exposing the photoresist layer. A conventional method for determining the position of the wafer in the exposure step is to first form an exposure alignment mark 7K (Alignment Mark) on the wafer. During the step of exposing the photoresist layer, the specific pattern of the mask is aligned with the exposure alignment mark so that the pattern on the mask is transferred to the correct position on the wafer. However, such an alignment method may still have some errors due to the limitation of resolution. When the integrated circuit manufacturing process enters the depth of sub-micron, such errors will seriously affect the quality of the wafer. In order to reduce the impact of the alignment deviation generated during the exposure step on the yield of the process, the current process steps are all in a batch (usually 25 wafers). Measure the misalignment at specific points on the wafer. Then, according to the alignment deviation measured at different points on the wafer, the correction amount required for the other wafers in the same batch during the exposure step is calculated. Fig. 1A shows a top view of a conventional structure for detecting the misalignment of exposure. Referring to FIG. 1A, the wafer 100 has an exposure alignment mark 102 and an outer layer mark 104. The outer layer mark 104 is arranged in a square shape on the wafer 100. 3 This paper size is applicable to the National Standard (CNS) A4 specification (2) 0 × 297 mm (please read the precautions on the back before filling this page) — printed by the Intellectual Property Bureau of the Ministry of Economic Affairs and printed by the Consumer Cooperative Society α Economy Printed by the Consumers' Cooperative of the Ministry of Intellectual Property Bureau Λ7 B7 V. Description of the Invention (v) Among them, the outer label 104 is composed of four trenches 104a, 104b, 104c, and 104d. The material of the inner layer marking 106 is a photoresist, and the formation method is to form a photoresist layer (not shown in the figure) on the wafer 100 'by aligning the photomask with the exposure alignment mark 102 (not shown in the figure) (In the figure) to determine the position of the wafer 100 by using a specific pattern on the wafer, and then perform photoresist layer exposure and development steps to form a square inner layer mark 106 on the wafer 100. After the alignment of the exposure alignment mark 102, the inner layer mark 106 is located approximately in the square in which the outer layer mark 104 is arranged. Among them, the inner layer designation 106 is composed of four strip structures 106a, 106b, 106c, and 106d. The inner layer mark 106 was originally intended to be formed in the center of the outer layer mark 104, and each side of the inner layer mark 106 and the corresponding side of the outer layer mark 104 were parallel to each other and maintained at the same distance. However, when there is a deviation in the alignment of the exposure step, the inner layer mark 10 will deviate from the center of the outer layer mark 104. The degree of deviation is the alignment deviation of the wafer 100 in this area. In order to explain clearly the method of detecting the misalignment, the horizontal direction in FIG. 1A is defined as the X-axis, and the vertical direction in FIG. 1A is defined as the Y-axis. The conventional method for detecting the misalignment is to select a first measurement line 108 ′ that is parallel to the X axis, where the first measurement line 108 and the grooves 104 a and 104 c of the outer layer mark 104 meet at A and A4, respectively. The first measurement line 108 and the strip-shaped structures 106a and 106c indicated by the inner layer 106 respectively meet at A2 and A3. The X coordinate of 'A, is X1, the X coordinate of a2 is χ2, and the X coordinate of A3 is x3', and the coordinate of A4 is X4. The difference between the average 値 of χ and χ4 and the average 値 of x2 and x3 'is the misalignment in the X direction caused by the exposure step. 4 (Please read the notes on the back before filling out this page) * -------- Order ---------% This paper size applies to Chinese National Standards < CNS) A4 Specifications < 210x297 Li) 269 2 * 7 kw 4 6 S h ,, ί ·
4653twf,doc/00S Α7 Β7 五、發明說明（、） 接著，選定一條平行於Y軸的第二測量線no，並且 以相同於上述的方法測量出曝光步驟在Y方向上所造成的 對準偏差。 請參照第1B圖，當晶圓100在進行曝光步驟時產生 旋轉的偏差時，內層標示106的每一邊與其外層標示104 之對應邊就會產生一個夾角，而不再有平行的關係。此時， 如果以上述的方法檢測其對準偏差，則所檢測出的對準偏 差將會因爲所選取的測量線的位置不同而有差異。在第1B 圖中，以第三測量線112爲基準所獲得之X方向的對準偏 差將與以第四測量線114爲基準所獲得之X方向的對準偏 差將不相同。而且在測量Y方向的偏差量時也會發生同樣 的情形。這會造成以所獲得之對準偏差所計算出之晶圓的 修正量不正確，如果根據此不正確的修正量來修正其他晶 圓在進行曝光步驟時的位置，將導致光罩的圖案的不當轉 移。 另一方面，晶圓在進行光阻層曝光的步驟之前，通常 已經進行了一些沉積的步驟。因而在外層標示104的凹槽 中會有一些沉積物。雖然這些沉積物並不會將外層標示104 的凹槽都塡滿，但是如果凹槽內的沉積物在凹槽中沉積的 情形不均勻或是發生缺陷，將造成所檢測之外層標示104 的位置不正確的問題，因而導致無法檢測曝光步驟之對準 偏差的情形。 因此本發明提供一種檢測對準偏差的方法與用以檢測 對準偏差的對準標示結構，可以避免因爲晶圓的旋轉或是 5 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公爱） (請先閱讀背面之注意事項再填寫本頁) 裝 訂---------飧 經濟部智慧財產局員工消費合作社印製 經濟部智慧財產局員工消費合作社印製 4⑽2Ί 4653twf.doc/008 五、發明說明（Y) 沉積於外層標示之沉積物不均勻與缺陷所造成之無法檢測 對準偏差的問題。 本發明提供一種檢測對準偏差的方法，在已形成有曝 光對準標示的晶圓上形成具有外層圓弧的外層標示。其 中，外層圓弧具有外層圓心。接著，在晶圓上形成光阻層 並且以曝光對準標示對準光罩之特定圖案來決定晶圓的位 置以及進行曝光的步驟。接著，進行顯影的步驟，以於晶 圓上形成具有內層圓弧的內層標示。其中，預定形成的內 層標示是以外層圓心爲圓心的內層圓弧，但是由於曝光的 步驟會有偏差，因此所形成之內層圓弧並不一定會與外層 圓弧具有相同的圓心。爲了淸楚的說明，以下將把實際上 形成之內層圓弧的圓心定義爲內層圓心。 接著，在外層圓弧上取點，以幾何方法計算出外層圓 心的位置，並且在內層圓弧上取點，同樣以幾何方法計算 出內層圓心的位置。之後，比較內層圓心與外層圓心之位 置的差異，以得到在曝光步驟時所產生的對準偏差。 在量測到晶圓的對準偏差之後，即可根據在晶圓之不 同位置上所量測到之對準偏差，計算出後續進行曝光步驟 之晶圓所需之修正量。 本發明提供一種對準標示的結構，在晶圓上具有曝光 對準標示 '外層標示以及內層標示。其中外層標示具有外 層圓弧，且此外層圓弧是以外層圓心爲圓心。而內層標示 具有內層圓弧，且內層圓弧是以內層圓心爲圓心。 本發明的特徵在於形成具有外層圓弧的外層標示以及 6 本紙張尺度適用中國國家標準（CNS)A4規格（21〇 χ 297公萤） J--------- 0 I-----1 訂-----I---功' (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 .269^1 A7 465 3twf.doc/008 ___B7__ 五、發明說明（匕） 具有內層圓弧的內層標示。由於由圓弧上的任三點的位置 就可以推算出圓心的位置，因此可以本發明的方法可以在 分別在內層圓弧與外層圓弧上取點之後，直接以幾何方法 推算出內層圓心與外層圓心的位置及其差異’而獲得對準 偏差，不需要分別以X方向與Y方向來進行。 其次，本發明的方法是以內層圓心與外層圓心之位置 的差異來檢測對準偏差，不需要選取測量線’所以即使晶 圓產生旋轉的偏差，也不會造成所得到之偏差値不正確的 問題。 另一方面，由於可以在外層圓弧與內層圓弧上取較多 的點來增加其圓心位置的精準度，因此可以克服因爲外層 標示中之沉積物不均勻或是缺陷所導致之無法檢測對準偏 差的問題。 爲讓本發明之上述和其他目的、特徵、和優點能更明 顯易懂，下文特舉一較佳實施例，並配合所附圖式，作詳 細說明如下： 圖式之簡單說明： 第1A圖繪示習知一種用以檢測對準偏差之結構的上 視圖； 第1B圖繪示一種習知檢測對準偏差所產生之情形的 上視圖；以及 第2圖繪示根據本發明之一較佳實施例的一種用以檢 測曝光對準偏差之結構的上視圖。 圖式之標記說明： (請先閱讀背面之注意事項再填寫本頁) 裝---- 訂---------竣 本紙張尺度適用中®國家標準（CNS)A4規格（210 公釐） 1 4653 twr.doc/008 A7 B7 五、發明說明（C ) 100 ' 200 '晶圓 102、 104、 104a 106 ' 106a 2〇2 :曝光對準標示 204 :外層標示 104b、104c、104d :溝渠 210 :內層標示 106b、106c、l〇6d :條狀結構 108 ： 第一測量線 110 ： 第二測量線 112 ： 第三測量線 114 ： 第四測量線 206 ： 外層圓弧 208 ： 外層圓心 210 ： 內層圓弧 214 ： 實施例 內層圓心 (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 請參照第2圖，在已形成有曝光對準標示2〇2的晶圓 2〇〇上形成具有外層圓弧206的外層標示204。其中外層 標示204比如爲溝渠，而外層圓弧206則是指外層標示204 所形成之以外層圓心208爲圓心的一段圓弧或是一個完整 的圓形。接著，形成光阻層（未繪示於圖中），並利用曝光 對準標示202對準光罩（未繪示於圖中）上之特定圖案，以 決定晶圓200之位置。之後，進行曝光與顯影的步驟，以 於晶圓200上形成具有內層圓弧210的內層標示212。其 中，內層標示212的材質比如爲光阻，而內層圓弧210則 裝·-------訂--------•線 本紙張尺度適用中國國家標準（CNS)A4規格（210 X 297公釐〉 26927 4653 twf.doc/〇〇8 A7 B7 經濟部智慧財產局員工消費合作社印製 五、發明說明（7 ) 爲其所形成之以內層圓心214爲圓心的一段圓弧或是一個 完整的圓形。如果在對準的過程中，沒有發生誤對準 (Misalign)的現象，則內層圓心214將與外層圓心208將 重合。但是由於在曝光的步驟中會產生偏差，因此內層圓 心214與外層圓心208在實際的情形上不一定重合。而內 層圓心214與外層圓心208之位置的差異是由於在曝光時 沒有完全對準而產生的，因此稱爲對準偏差。 接著，在外層圓弧206上取至少三點的位置，以幾何 方法計算出外層圓心208的位置，並且在內層圓弧210上 取至少三點的位置，以同樣的幾何方法計算出內層圓心214 的位置。之後，比較內層圓心214與外層圓心208之位置 的差異，以得到在曝光步驟時所產生的對準偏差。 由本發明所提供的方法在晶圓上一些特定的點上求得 對準偏差之後，即可根據這些特定點在晶圓上的位置以及 所量測出來的對準偏差計算出後續之晶圓在進行曝光步驟 時的修正量。 本發明的優點在於形成具有外層圓弧的外層標示以及 具有內層圓弧的內層標示。由於由圓弧上的任三點的位置 就可以推算出圓心的位置，因此可以本發明的方法可以在 分別在內層圓弧與外層圓弧上取點之後.，直接以幾何方法 推算出內層圓心與外層圓心的位置及其差異，而獲得晶圓 的對準誤差，不需要分別以X方向與Y方向來進行。 其次，本發明的方法是以內層圓心與外層圓心之位置 的差異來檢測對準偏差，不需要選取測量線，所以即使晶 9 本紙張尺度適用中0國家標準（CNS)A'l規格（210 x 297公楚） n 1 ϋ ϋ > I n ^eJ I I— I (請先閱讀背面之注意事項再填寫本頁) i26927 A74653twf, doc / 00S Α7 Β7 5. Description of the Invention (,) Next, select a second measurement line no parallel to the Y axis, and measure the alignment deviation caused by the exposure step in the Y direction in the same way as above. . Please refer to FIG. 1B. When the wafer 100 undergoes rotation deviation during the exposure step, each side of the inner layer mark 106 and the corresponding side of the outer layer mark 104 will generate an angle, and there is no longer a parallel relationship. At this time, if the alignment deviation is detected by the above method, the detected alignment deviation will be different due to the different positions of the selected measurement lines. In FIG. 1B, the alignment deviation in the X direction obtained using the third measurement line 112 as a reference will be different from the alignment deviation in the X direction obtained using the fourth measurement line 114 as a reference. The same situation also occurs when measuring the amount of deviation in the Y direction. This will cause the correction amount of the wafer calculated based on the obtained alignment deviation to be incorrect. If the position of other wafers during the exposure step is corrected based on this incorrect correction amount, the pattern of the photomask will be incorrect. Transfer. On the other hand, the wafer is usually subjected to some deposition steps before the photoresist layer exposure step. There will therefore be some deposits in the grooves of the outer layer designation 104. Although these deposits will not fill up the grooves of the outer layer mark 104, if the deposits in the grooves are unevenly deposited or defective, the position of the outer layer mark 104 will be detected Incorrect problem, which makes it impossible to detect the misalignment of the exposure step. Therefore, the present invention provides a method for detecting misalignment and an alignment mark structure for detecting misalignment, which can avoid because of wafer rotation or 5 paper sizes that are applicable to the Chinese National Standard (CNS) A4 specification (210 X 297). Gongai) (Please read the precautions on the back before filling out this page) Binding -------- 员工 Printed by the Employee Consumption Cooperative of the Intellectual Property Bureau of the Ministry of Economy 4 印 2Ί 4653twf. doc / 008 5. Description of the invention (Y) The problem of undetectable misalignment caused by uneven deposits and defects deposited on the outer layer markings. The invention provides a method for detecting misalignment. An outer layer mark having an outer layer arc is formed on a wafer on which an exposure alignment mark has been formed. Among them, the outer arc has an outer circle center. Next, a photoresist layer is formed on the wafer, and a specific pattern of the photomask is aligned with the exposure alignment mark to determine the position of the wafer and the steps of performing exposure. Next, a developing step is performed to form an inner layer mark having an inner layer arc on the wafer. Among them, the planned inner layer designation is the inner layer arc whose center is the center of the outer layer. However, due to deviations in the exposure steps, the inner arc formed may not have the same center as the outer arc. For the sake of clarification, the circle center of the inner arc actually formed will be defined as the inner circle center below. Then, take a point on the outer arc, and calculate the position of the outer circle center geometrically, and take a point on the inner arc, and also calculate the position of the inner circle center geometrically. Then, the difference between the positions of the center of the inner circle and the center of the outer circle is compared to obtain the alignment deviation generated during the exposure step. After measuring the alignment deviation of the wafer, the correction amount required for subsequent wafer exposure steps can be calculated based on the alignment deviation measured at different positions of the wafer. The invention provides an alignment mark structure, which has an exposure alignment mark 'outer layer mark and an inner layer mark on a wafer. The outer layer is marked with an outer arc, and the outer arc is the center of the outer circle. The inner layer has an inner arc, and the inner arc is centered on the inner circle center. The invention is characterized by forming an outer layer mark with an outer arc and 6 paper sizes that are applicable to the Chinese National Standard (CNS) A4 specification (21〇χ 297 公 fluorescent) J --------- 0 I --- --1 Order ----- I --- Gong '(Please read the notes on the back before filling this page) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs. 269 ^ 1 A7 465 3twf.doc / 008 ___B7__ V. Description of the Invention (Dagger) The inner layer mark with inner arcs. Since the position of the center of the circle can be calculated from the position of any three points on the arc, the method of the present invention can directly calculate the inner layer by geometric methods after taking points on the inner arc and the outer arc respectively. The position of the center of the circle and the center of the outer layer and their differences' to obtain the alignment deviation do not need to be performed in the X direction and the Y direction, respectively. Secondly, the method of the present invention detects the alignment deviation based on the difference between the positions of the inner circle center and the outer circle center. It is not necessary to select a measurement line, so even if the wafer has a rotation deviation, it will not cause the obtained deviation. problem. On the other hand, because you can take more points on the outer arc and the inner arc to increase the accuracy of the center position, it can overcome the undetectability caused by uneven deposits or defects in the outer layer markings. Problems with misalignment. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is described below in detail with the accompanying drawings as follows: Brief description of the drawings: FIG. 1A FIG. 1B shows a conventional top view of a structure for detecting misalignment; FIG. 1B shows a conventional top view of a situation generated by detecting misalignment; and FIG. 2 shows a preferred embodiment according to the present invention. A top view of a structure for detecting a deviation in exposure alignment of an embodiment. Description of the drawing marks: (Please read the precautions on the back before filling out this page) Loading ---- Ordering --------- Completion of this paper standard application ® National Standard (CNS) A4 Specification (210 (Mm) 1 4653 twr.doc / 008 A7 B7 V. Description of the invention (C) 100 '200' wafer 102, 104, 104a 106 '106a 2202: Exposure alignment mark 204: Outer layer mark 104b, 104c, 104d : Ditch 210: Inner layer marks 106b, 106c, 106d: Strip structure 108: First measurement line 110: Second measurement line 112: Third measurement line 114: Fourth measurement line 206: Outer arc 208: Outer layer Center of circle 210: Inner circle 214: Example of inner circle (please read the precautions on the back before filling this page) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economics Please refer to Figure 2, where the exposure alignment has been formed An outer layer mark 204 having an outer layer arc 206 is formed on the wafer 200 marked 200. The outer layer mark 204 is, for example, a ditch, and the outer layer arc 206 refers to a circular arc or a complete circle formed by the outer layer center 204 formed by the outer layer mark 204. Next, a photoresist layer (not shown in the figure) is formed, and a specific pattern on the photomask (not shown in the figure) is aligned with the exposure alignment mark 202 to determine the position of the wafer 200. Thereafter, steps of exposure and development are performed to form an inner layer mark 212 having an inner layer arc 210 on the wafer 200. Among them, the material of the inner label 212 is, for example, photoresist, and the inner arc 210 is installed. A4 specifications (210 X 297 mm) 26927 4653 twf.doc / 〇〇8 A7 B7 Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs V. Invention Description (7) It is a section with the inner center 214 as the center The arc or a complete circle. If there is no misalignment during the alignment process, the inner circle center 214 will coincide with the outer circle center 208. However, it will be in the exposure step. There is a deviation, so the inner circle center 214 and the outer circle center 208 do not necessarily coincide in the actual situation. The difference between the position of the inner circle center 214 and the outer circle center 208 is due to the incomplete alignment during exposure, so it is called Alignment deviation. Next, take the position of at least three points on the outer arc 206, geometrically calculate the position of the outer circle center 208, and take the position of at least three points on the inner arc 210, using the same geometric method The position of the inner circle center 214 is calculated. Then, the difference between the positions of the inner circle center 214 and the outer circle center 208 is compared to obtain the alignment deviation generated during the exposure step. After the alignment deviation is obtained at some specific points on the wafer by the method provided by the present invention, According to the position of these specific points on the wafer and the measured alignment deviation, the correction amount of the subsequent wafer during the exposure step can be calculated. The advantage of the present invention is to form an outer layer mark with an outer arc. And the inner layer mark with the inner arc. Since the position of the center of the circle can be calculated from the position of any three points on the arc, the method of the present invention can be taken on the inner arc and the outer arc respectively After the point, the position and difference between the inner circle center and the outer circle center are directly calculated by the geometric method, and the alignment error of the wafer does not need to be performed in the X direction and the Y direction respectively. Second, the method of the present invention is The difference between the position of the inner circle center and the outer circle center is used to detect the misalignment. It is not necessary to select a measurement line, so even if the paper size is 9, the national standard (CNS) A is applicable. 'l size (210 x 297 cm) n 1 ϋ ϋ > I n ^ eJ I I— I (Please read the notes on the back before filling this page) i26927 A7
4653twf.doc/00S ___B7 五、發明說明（$ ) 圓產生旋轉的偏差，也不會造成以對準偏差所計算出之修 正量不正確的問題。 另一方面，由於可以在外層圓弧與內層圓弧上取較多 的點來增加其圓心位置的精準度，因此可以克服因爲外層 圓弧中之沉積物有不均勻的現象或是缺陷所導致之無法檢 測對準偏差的問題。 雖然本發明已以一較佳實施例揭露如上，然其並非用 以限定本發明，任何熟習此技藝者，在不脫離本發明之精 神和範圍內，當可作各種之更動與潤飾，因此本發明之保 護範圍當視後附之申請專利範圍所界定者爲準。 —------------ --------訂·-------- (請先閱讀背面之注意事項再填寫本頁) 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中國國家標準（CNS)A·!規格（210 X 297公釐）4653twf.doc / 00S ___B7 V. Description of the Invention ($) The rotation deviation of the circle will not cause the problem that the correction amount calculated by the alignment deviation is incorrect. On the other hand, because you can take more points on the outer arc and the inner arc to increase the accuracy of the center position, it can overcome the phenomenon of unevenness or defects in the sediments in the outer arc. This makes it impossible to detect misalignment. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and decorations without departing from the spirit and scope of the present invention. The scope of protection of the invention shall be determined by the scope of the attached patent application. —------------ -------- Order · -------- (Please read the notes on the back before filling out this page) Employees of the Intellectual Property Bureau of the Ministry of Economic Affairs The paper size printed by the consumer cooperative is applicable to the Chinese National Standard (CNS) A ·! Specifications (210 X 297 mm)