436975 5 8 5 4 twf . doc /0 0 8 經濟部智慧財展局員工消资合作社印製 五、發明説明（(） 本發明是有關於一種積體電路的製程，且特別是有 關於一種淺溝渠隔離的製程。 在闻等的互補式金氧半電晶體（Complementary Metal-Oxide Semiconductor，CMOS)製程中，使用化學 機械硏磨法（Chemical Mechanical Polishing，CMP)處理 淺溝渠隔離（Shallow Trench Isolation，STI)可以得到全 面性的平坦化結果，然而，最主要的爭議是化學機械硏 磨步驟的最後平面化結果極度依賴主動區的圖案密度。 在進行化學機械硏磨步驟時，在大主動區上的氧化物具 有一較低的局部磨除速率，因爲氮化物硬度較氧化物 高，需要一較長的硏磨時間確定將氮化矽層上的氧化層 以完全被去除，因此當磨除大主動區中氮化物上所有的 氧化物時，將會造成密集細胞區中氧化物的過度硏磨， 而造成溝渠中氧化物表面凹陷（dishmg)的現象。 習知一種避免氧化物凹陷的方法，是先以反轉罩幕 製程去除主動區上的氧化物，接著再進行一化學機械硏 磨步驟以磨除溝渠上超出氮化矽層的氧化物，由於已先 蝕刻掉大主動區上的氧化物，因此能解決前段所述之磨 除速率不一的問題。然而使用反轉罩幕對不準時，罩幕 圖案會偏離主動區，暴露出部分位於淺溝渠區域的氧化 層，進行蝕刻時會使主動區之間的氧化物會被蝕刻掉一 部份，而形成微小溝渠，第1A圖至第1D圖係繪示形成 這種微小溝渠的流程圖。 請參照第1A圖，提供一基底100，一墊氧化層102 3 ---Ί—------Λ-- (請先閱讀背面之注意事項再填寫本頁) 訂 味 本紙張尺度適用中国國家揉準（CNS ) Α4規格（210 X 297公釐） A7 B7 4369 7 5 5854twf.doc/008 五、發明説明（飞） 形成在基底1〇〇上，然後，一氮化砂層104形成在墊氧 化層102上，藉由一形成在氮化矽層104上之圖案化光 阻層爲罩幕，進行一溝渠蝕刻步驟，再形成一襯裡氧化 層，去除圖案化光阻層之後，再回塡一化學氣相沉積 (Chemical Vapor Deposition，CVD)氧化物 106 1 最後， 一反轉罩幕108形成在化學氣相沉積氧化物106上。 請繼續參照第1B圖，以氮化矽層104爲蝕刻終止 層（Etching Stop)，進行一回鈾（Etch Back)步驟以去除氮 化矽層104上的化學氣相沉積氧化物106,由於微影製 程的對不準，使得位在氮化矽層104旁邊下方的化學氣 相沉積氧化物106會被蝕刻掉一部份，形成微小溝渠 118° 請參照第1C圖，在去除反轉罩幕108 1以裸露出 化學氣相沉積氧化物106之後，仍可看到淺溝渠結構之 間具有微小的溝渠空隙118未被塡滿。 請參照第1D圖，以氮化矽層104爲終止層，進行 一化學機械硏磨步驟，由於大主動區Π2已預先蝕刻掉 大部份的化學氣相沉積氧化物106，因此，在密集細胞 區中將不會因過度硏磨而形凹陷，但是，微小溝渠118 的形成卻是來自於由微影製程的反轉罩幕對不準，以及 回蝕步驟所造成的（如第1B圖所示）。 習知另有一種解決上述因爲反轉罩幕對不準而產生 微小溝渠結構的方法，將反轉罩幕上的圖案尺寸縮小， 使其暴露出的主動區隨之縮小，如此可以使反轉罩幕有 4 (請先閲讀背面之注意事項再填寫本頁) 訂 唆！ 經濟部智慧財產局員工消費合作社印製 本紙張尺度適用中闺國家標準（CNS ) A4規格（210X297公釐） Γ 436975 經濟部智慧財產局員工消費合作社印製 五、發明説明（1 ) 較大的對準窗口。將反轉罩幕中對準主動區的窗口設計 的比主動區還要小時，雖然可解決上述這種因微影製程 的不對準而形成的微小溝渠，但是當半導體結構尺寸日 益縮小’主動區的線寬已達臨界尺寸時，將無法再進一 .步的縮小反轉罩幕的圖案。也就是說由於曝光光源有解 析度上的限制，因此會有最小臨界尺寸的設計準則之限 制，所以反轉罩幕在密集細胞區中之窗口的臨界尺寸具 有一極限値，而無法再縮小。 因此，本發明的目的之一就是在提供一種淺溝渠隔 離的製程，可避免在密集細胞區中形成不必要的微小溝 渠。 本發明的另一目的就是在提供一種淺溝渠隔離的製 程，就是在提供一種淺溝渠隔離的製程，在微影製程中， 不需要縮小反轉罩幕的圖尺寸，也無須擔心對不準時可 能會有微小溝渠產生，因此不僅不會縮小製程窗口 (process window)，反而可以擴大製程窗口。 根據本發明之上述目的，提供一種淺溝渠隔離的製 程，其係在基底上形成墊氧化層，在墊氧化層上形成氮 化矽層，進行溝渠蝕刻步驟以蝕刻出複數個大溝渠以及 複數個小溝渠，在溝渠中以及氮化矽層上沉積化學氣相 沉積氧化物，在化學氣相沉積氧化物上形成旋塗式玻璃 層，在旋塗式玻璃層上形成圖案化之光阻層以覆蓋住溝 渠的上方，並暴露出非溝渠的部分，對暴露在反轉罩幕 下之旋塗式玻璃層進行離子植入步驟，去除反轉罩幕之 5 (請先閲讀背面之注意事項再填寫本頁) 本紙張尺度適用中國國家標準（CNS > A4規格（210X297公釐） I 43^975 5854twf.doc/008 五、發明説明（G) 後，以氮化矽層爲終止層，進行化學機械硏磨步驟。 爲讓本發明之上述目的、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： 圖式之簡單說明： 第1A圖至第1D圖係繪示在習知的一種淺溝渠隔 離之製程中，複數微小溝渠形成的流程圖： 第2A圖至第2G圖係繪示本發明的一種淺溝渠隔 離之製程；以及 第3圖係繪示習知在幾種氧化薄膜中進行一離子植 入步驟，在後續的化學機械硏磨過程中，其磨除厚度^對 磨除時間的變化圖。 第4圖係繪示習知在幾種氧化薄膜中進行一離子植 入步驟，在後續的化學機械硏磨過程中，其磨除速率對 離子植入的劑量之變化圖。 (請先閱讀背面之注意事項再填寫本頁)436975 5 8 5 4 twf. Doc / 0 0 8 Printed by the Consumers' Cooperative of the Smart Finance and Exhibition Bureau of the Ministry of Economic Affairs 5. Description of the Invention (() The present invention relates to a process for integrated circuits, and in particular, to a shallow circuit Process of trench isolation. In the complementary metal-oxide semiconductor (CMOS) process of Wen et al., Chemical mechanical polishing (CMP) is used to process shallow trench isolation (Shallow Trench Isolation, STI) can obtain comprehensive planarization results, however, the main controversy is that the final planarization result of the chemical mechanical honing step is extremely dependent on the pattern density of the active region. When performing the chemical mechanical honing step, on the large active region The oxide has a lower local removal rate, because the nitride has a higher hardness than the oxide, and requires a longer honing time to determine that the oxide layer on the silicon nitride layer is completely removed, so when the removal is large When all the oxides on the nitride in the active area, it will cause excessive honing of the oxides in the dense cell area, and cause the oxide surface in the trench. The phenomenon of dishmg is known. A known method to avoid oxide sag is to first remove the oxide on the active area by a reverse mask process, and then perform a chemical mechanical honing step to remove excess nitridation on the trench. The oxide of the silicon layer, because the oxide on the large active area has been etched away first, can solve the problem of the different abrasion rate described in the previous paragraph. However, when the inversion mask is used, the mask pattern will deviate from the active one. Area, the oxide layer located in the shallow trench area is exposed, and the oxide between the active area will be partially etched during the etching to form a micro trench. Figures 1A to 1D show the formation of this. A flowchart of a micro trench. Please refer to Figure 1A to provide a substrate 100 and an oxide layer 102 3 --- Ί -------- Λ-- (Please read the precautions on the back before filling this page ) Customize the paper size Applicable to the Chinese National Standard (CNS) A4 specification (210 X 297 mm) A7 B7 4369 7 5 5854twf.doc / 008 5. Description of the invention (flying) is formed on the substrate 100, then, A nitrided sand layer 104 is formed on the pad oxide layer 102. A patterned photoresist layer formed on the silicon nitride layer 104 is used as a mask, a trench etching step is performed, and a liner oxide layer is formed. After the patterned photoresist layer is removed, a chemical vapor deposition is performed again ( Chemical Vapor Deposition (CVD) oxide 106 1 Finally, a reversal mask 108 is formed on the chemical vapor deposition oxide 106. Please continue to refer to FIG. 1B, using the silicon nitride layer 104 as an etching stop layer. An Etch Back step is performed to remove the chemical vapor deposition oxide 106 on the silicon nitride layer 104. Due to the misalignment of the lithography process, the chemical vapor phase located below the silicon nitride layer 104 A portion of the deposited oxide 106 will be etched away to form a micro trench. 118 ° Please refer to Figure 1C. After removing the inversion mask 108 1 to expose the chemical vapor deposition oxide 106, the shallow trench structure can still be seen. There are tiny trench voids 118 in between. Referring to FIG. 1D, a chemical mechanical honing step is performed with the silicon nitride layer 104 as a stop layer. Since most of the chemical vapor deposition oxide 106 has been etched in advance in the large active region Π2, The area will not be recessed due to excessive honing. However, the formation of the micro-ditch 118 is caused by the misalignment of the inversion mask of the lithography process and the etch-back step (as shown in Figure 1B). Show). It is known that there is another method to solve the above-mentioned micro-ditch structure caused by the misalignment of the inversion mask. The size of the pattern on the inversion mask is reduced, so that the active area exposed by it is reduced, so that the inversion can be reversed. There are 4 masks (Please read the precautions on the back before filling this page) Order! Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs of the Consumer Cooperatives The paper size is applicable to the Chinese National Standard (CNS) A4 specification (210X297 mm) Γ 436975 Printed by the Intellectual Property Bureau of the Ministry of Economic Affairs of the Consumer Cooperatives of the Ministry of Economic Affairs 5. Description of invention (1) Align the window. The window designed to align the active area in the inversion mask is smaller than the active area. Although it can solve the micro-channels caused by the misalignment of the lithography process, the size of the semiconductor structure is shrinking. When the line width has reached the critical size, the pattern of the reversal mask cannot be further reduced. That is to say, because the exposure light source has a resolution limitation, there is a limitation on the design criterion of the minimum critical size. Therefore, the critical size of the window of the inversion mask in the dense cell area has a limit, and it cannot be reduced. Therefore, one of the objects of the present invention is to provide a process for isolation of shallow trenches, which can avoid the formation of unnecessary micro trenches in dense cell areas. Another object of the present invention is to provide a shallow trench isolation process, that is, to provide a shallow trench isolation process. In the lithography process, there is no need to reduce the size of the reversal mask, and there is no need to worry about the possibility of being out of time. There will be tiny trenches, so not only will the process window not be reduced, but the process window can be enlarged. According to the above object of the present invention, a process for isolating a shallow trench is provided. A pad oxide layer is formed on a substrate, a silicon nitride layer is formed on the pad oxide layer, and a trench etching step is performed to etch a plurality of large trenches and a plurality of trenches. In small trenches, a chemical vapor deposition oxide is deposited in the trench and on the silicon nitride layer, a spin-on glass layer is formed on the chemical vapor deposition oxide, and a patterned photoresist layer is formed on the spin-on glass layer. Cover the top of the ditch and expose the non-ditch. Perform ion implantation on the spin-coated glass layer exposed under the reversing mask. Remove the reversing mask. 5 (Please read the precautions on the back before filling (This page) This paper is in accordance with Chinese national standards (CNS > A4 size (210X297mm) I 43 ^ 975 5854twf.doc / 008 5. After the description of the invention (G), the silicon nitride layer is used as the stop layer for chemical Mechanical honing steps. In order to make the above-mentioned objects, features, and advantages of the present invention more comprehensible, the following describes the preferred embodiments in detail with the accompanying drawings, as follows: Brief description of the drawings Ming: Figures 1A to 1D are flowcharts showing the formation of a plurality of micro trenches in a conventional process for the isolation of shallow trenches: Figures 2A to 2G are schematic diagrams of a shallow trench isolation of the present invention The manufacturing process; and FIG. 3 is a graph showing a conventional ion implantation step in several kinds of oxide films, and the subsequent change in the thickness ^ versus the removal time in the subsequent chemical mechanical honing process. FIG. 4 The figure shows a conventional ion implantation step in several oxide films. In the subsequent chemical mechanical honing process, the change of the removal rate to the dose of ion implantation. (Please read the precautions on the back first (Fill in this page again)
、tT 經濟部智慧財產局員工消費合作社印製 標號說明： 100 ： 基底 102 ： 墊氧化層 104 ： 氮化矽層 106 *- 化學氣相沉積氧化物 108 ： 反轉罩幕 110 ： 密集細胞區 112 ： 大主動區 114 ： 大的淺溝渠隔離 6 本紙張尺度逋用中國國家標準（CNS } A4規格（210X297公釐） 經濟部智慧財產局員工消费合作社印製 436 9 ^ 5 5 8 5 4 twf-d3c/008 五、發明説明（ς) 116： 窗口 118： 微小溝渠 2〇〇 : 基底 202 ： 墊氧化層 204 ： 氮化矽層 206 ： 化學氣相沉積氧化物 208 : 旋塗式玻璃層 210 : 第二光阻層 212 ： 植入的離子 214 ： 密集細胞區 216 ： 大主動區 218 ： 大的淺溝渠隔離 220 ： 離子植入的旋塗式玻璃層 實施例 第2A圖至第2G圖係繪示本發明的一種淺溝渠隔 離之製程。 請參照第2A圖，提供一基底200，一墊氧化層202 形成在基底200上，然後，一氮化矽層2〇4形成在墊氧 化層202上，藉由一形成在氮化砂層204上之圖案化之 第一光阻層爲罩幕，進行一溝渠蝕刻步驟’再形成一襯 氧化層，去除圖案化之第一光阻層之後’再利用化學氣 相沉積（Chemical Vapor Deposition ’ CVD)法沉積一氧化 物206，此氧化物206塡充於溝渠中的部分，其上表面 需略高於基底之上表面。 7 本紙張尺度適用中國國家標準（CNS > A4规格（2丨0：<297公釐） I I. ^ H I I ±衣 ~~ 訂 I 線 (請先閲讀背面之注意事項再填寫本頁) 436975 5854twf.doc/008 經濟部智慧財產局員工消費合作社印製 五、發明説明（“） 請參照第2B圖，一旋塗式玻璃（Spin-On glass，SOG) 層208形成在氧化物206上，之後，將一層圖案化之第 二光阻層210形成在旋塗式玻璃層208上，此圖案化之 第二光阻層210覆蓋住溝渠的上方，並暴露出非溝渠的 .部分。 請參照第2C圖，對暴露出來的旋塗式玻璃層208 進行一道離子植入步驟，所用的能量約爲120〜160k電 子伏特，較佳的能量約爲140k電子伏特，離子的劑量 約爲1〜2x 1015原子/平方公分，植入的離子212包括硼 離子或磷離子。 第3圖至第4圖係繪示習知在一種化學機械硏磨製 程中，對不同的氧化物進行一硼離子的離子植入步驟， 比較其相對的磨除速率的結果。其中，型態A是矽氧烷 類（Siloxane)的旋塗式玻璃薄膜，型態B是含甲基矽酸 鹽（Methylsilsequioxane，MSQ)的旋塗式玻璃薄膜 '型態 A與型態B均是有機的旋塗式玻璃薄膜，PE-TEOS是四 乙基石夕酸鹽（Tetra-Ethyl-Ortho-Silcate，TE0S)以電漿加 強式（Plasma-Enhanced)化學氣相沉積法所形成之二氧化 矽薄膜，離子的能量約爲140k電子伏特，離子的劑量 約爲1〜2x 1015原子/平方公分。 如第3圖所示，經過離子植入後的型態A以及型 態B，其化學機械硏磨之磨除速率均增加，其中又以型 態A的表現最爲顯著，而PE-TE0S的磨除速率則不受 離子植入影響，一直維持不變，經離子植入後的型態A 8 (請先閱讀背面之注意事項再填寫本頁) 、?τ 本紙張尺度適用令國國家橾準（CNS ) A4規格（2丨0X297公着） 經濟部智慧財產局員工消費合作社印製 4 3 6 9 7 5 A7 5854twf.doc/008 D / 五、發明説明（7 ) 之磨除速率幾乎達到ΡΕ-TEOS的二倍。 如第4圖所示，型態A以及型態B的磨除速率與 離子植入的劑量有關，在型態A裡，當離子植入的劑量 爲lx 1015原子/平方公分時，磨除速率大幅增加，但是 再增加劑量至2x 1015原子/平方公分時，磨除速率維持 不變；在型態B裡，磨除速率隨劑量的增加而增加。 PE-TEOS則與離子植入的劑量無關。 由第3圖與第4圖可歸納得知：進行離子植入步驟 能增加有機的旋塗式玻璃薄膜對進行化學機械硏磨之磨 除速率，並且其磨除速率隨離子植入劑量的增加而增 加。 請繼續參照第2D圖，在離子植入步驟進行後，移 除圖案化之第二光阻層210。 請繼續參照第2E圖，進行一化學機械硏磨步驟， 由於植入離子的旋塗式玻璃層220具有比未經離子植入 的旋塗式玻璃層208還要快的磨除速率，所以，當磨除 掉所有之離子植入的旋塗式玻璃層220時1在主動區以 外的氧化層206上還會留下一部份之未經離子植入的旋 塗式玻璃層208,也就是在溝渠的上方會殘留部分的旋 塗式玻璃208。 請繼續參照第2F圖，繼續進行化學機械硏磨步驟， 當磨除掉剩餘之未經離子植入的旋塗式玻璃層2〇8時， 主動區上的氧化層206也會被硏磨掉，位於主動區氮化 矽層204上的氧化物206會較其他區域的氧化物先被硏 9 ---.--------ί,------訂--^-----唆.1 (請先閱讀背面之注意事項再填寫本頁) 本纸張尺度適用中國國家標準（CNS ) Α4規格（2ΙΟΧ 297公釐） 4369 7 5 五、發明説明（》） 磨掉，因此無須擔心在溝渠部分會有凹陷的現象，也不 會在氮化矽層204上有氧化物的殘留，最後即形成如第 2G圖所示’具有平坦表面的淺溝渠隔離結構。 (請先閲讀背面之注意事項再填寫本頁} 因此’本發明的優點係提出一種淺溝渠隔離的製 程，先在化學氣相沉積氧化物上再形成一層旋塗式玻 璃，再利用一形成在旋塗式玻璃層上的反轉罩幕來進行 一離子植入步驟，使主動區上之旋塗式玻璃層受到離子 植入的影響而增加對化學機械硏磨的磨除速率，在後續 的化學機械硏磨過程中可避免對密集細胞區做過度的硏 磨，所以，可以避免在密集細胞區中形成不必要的微小 溝渠。 本發明的另一優點係由於在化學氣相沈積的氧化物 上還覆蓋有一層旋塗式玻璃層，因此所用的化學氣相沉 積氧化物之厚度可以小於習知。 本發明的再另一優點係不需要擔心所用的圖案化之 第二光阻層因對不準而形成微小溝渠，因此可以製程窗 口較習知的方法大，在次微米技術中更加突顯這一重要 性。 經濟部智慧財產局員工消費合作社印製 綜上所述，雖然本發明已以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。 本纸張尺度適用中國國家標準（CNS ) Λ4規格（210Χ297公釐）, TT printed by the Intellectual Property Bureau of the Ministry of Economic Affairs, Consumer Cooperatives, printed label description: 100: substrate 102: pad oxide layer 104: silicon nitride layer 106 *-chemical vapor deposition oxide 108: inversion mask 110: dense cell area 112 ： Great active area 114 ： Large shallow trench isolation 6 This paper size adopts the Chinese national standard (CNS) A4 (210X297 mm) Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 436 9 ^ 5 5 8 5 4 twf- d3c / 008 V. Description of the invention 116: Window 118: Micro channel 2000: Substrate 202: Pad oxide layer 204: Silicon nitride layer 206: Chemical vapor deposition oxide 208: Spin-on glass layer 210: Second photoresist layer 212: Implanted ions 214: Dense cell area 216: Large active area 218: Large shallow trench isolation 220: Spin-coated glass layer of ion implantation Examples 2A to 2G A process for isolating a shallow trench according to the present invention is shown. Referring to FIG. 2A, a substrate 200 is provided, an oxide layer 202 is formed on the substrate 200, and then a silicon nitride layer 204 is formed on the pad oxygen. On layer 202, a patterned first photoresist layer formed on the nitrided sand layer 204 is used as a mask, and a trench etching step is performed to form a liner oxide layer, and the patterned first photoresist layer is removed. 'Chemical Vapor Deposition' (CVD) method is used to deposit an oxide 206. The oxide 206 is filled in the trench, and its upper surface needs to be slightly higher than the upper surface of the substrate. China National Standard (CNS > A4 specification (2 丨 0: < 297 mm) I I. ^ HII ± clothing ~~ Order I cable (please read the precautions on the back before filling this page) 436975 5854twf.doc / 008 Printed by the Consumer Cooperative of the Intellectual Property Bureau of the Ministry of Economic Affairs 5. Description of the invention (") Please refer to Figure 2B. A spin-on glass (SOG) layer 208 is formed on the oxide 206. After that, a layer A patterned second photoresist layer 210 is formed on the spin-on glass layer 208, and this patterned second photoresist layer 210 covers the trench and exposes the non-ditch portion. Please refer to FIG. 2C, The exposed spin-on glass layer 208 is subjected to a In the ion implantation step, the energy used is about 120 ~ 160k electron volts, the preferred energy is about 140k electron volts, the ion dose is about 1 ~ 2x 1015 atoms / cm2, and the implanted ions 212 include boron ions or phosphorus ion. Figures 3 to 4 show the results of conventionally performing a boron ion implantation step on different oxides in a chemical mechanical honing process, and comparing their relative removal rates. Among them, Form A is a spin-on glass film of Siloxane type, and Form B is a spin-on glass film containing Methylsilsequioxane (MSQ). It is an organic spin-coated glass film. PE-TEOS is a dioxide formed by Tetra-Ethyl-Ortho-Silcate (TE0S) by Plasma-Enhanced chemical vapor deposition. For silicon thin films, the energy of ions is about 140k electron volts, and the dose of ions is about 1 ~ 2x 1015 atoms / cm 2. As shown in Figure 3, the removal rate of chemical mechanical honing of Form A and Form B after ion implantation both increased, and the performance of Form A was the most significant, while PE-TE0S The abrasion rate is not affected by ion implantation, and remains unchanged. The form A 8 after ion implantation (please read the precautions on the back before filling this page),? Τ This paper size is applicable to the country 橾Standard (CNS) A4 (2 丨 0X297) Printed by the Consumer Cooperatives of the Intellectual Property Bureau of the Ministry of Economic Affairs 4 3 6 9 7 5 A7 5854twf.doc / 008 D / V. Description of the invention (7) The removal rate almost reached PE-TEOS is doubled. As shown in Figure 4, the removal rate of Form A and Form B is related to the dose of ion implantation. In Form A, when the dose of ion implantation is lx 1015 atoms / cm 2, the removal rate It increased significantly, but when the dose was increased to 2 × 1015 atoms / cm 2, the removal rate remained unchanged; in Type B, the removal rate increased with the increase of the dose. PE-TEOS is independent of the dose of ion implantation. It can be concluded from Figures 3 and 4 that the ion implantation step can increase the removal rate of the organic spin-coated glass film for chemical mechanical honing, and the removal rate increases with the increase of the ion implantation dose. While increasing. Please continue to refer to FIG. 2D. After the ion implantation step is performed, the patterned second photoresist layer 210 is removed. Please continue to refer to FIG. 2E to perform a chemical mechanical honing step. Since the ion-implanted spin-on glass layer 220 has a faster removal rate than the ion-implanted spin-on glass layer 208, When all ion-implanted spin-coated glass layers 220 are removed, a part of the non-ion-implanted spin-coated glass layer 208 will remain on the oxide layer 206 outside the active area, that is, A portion of the spin-on glass 208 remains above the trench. Please continue to refer to FIG. 2F and continue the chemical mechanical honing step. When the remaining spin-coated glass layer 208 without ion implantation is removed, the oxide layer 206 on the active area will also be honed away. The oxide 206 on the silicon nitride layer 204 in the active region will be etched before the oxide in other regions. 9 ---.-------- ί, ------ order-^- ---- 唆 .1 (Please read the precautions on the back before filling in this page) The paper size applies to the Chinese National Standard (CNS) Α4 specification (2ΙΟχ 297 mm) 4369 7 5 V. Description of the invention (") Grinding Therefore, there is no need to worry about the phenomenon of depression in the trench portion, and there will be no oxide residue on the silicon nitride layer 204, and finally a shallow trench isolation structure with a flat surface is formed as shown in FIG. 2G. (Please read the precautions on the back before filling in this page} Therefore, 'The advantage of the present invention is to propose a process for shallow trench isolation. First, a layer of spin-on-glass is formed on the chemical vapor deposition oxide, and The inversion mask on the spin-coated glass layer performs an ion implantation step, so that the spin-coated glass layer on the active area is affected by the ion implantation to increase the removal rate of chemical mechanical honing. Excessive honing of the dense cell area can be avoided during the chemical mechanical honing process, so unnecessary microchannels can be prevented from forming in the dense cell area. Another advantage of the present invention is that the oxide is deposited in the chemical vapor phase. It is also covered with a spin-on glass layer, so the thickness of the chemical vapor deposition oxide used can be less than conventional. Another advantage of the present invention is that there is no need to worry about the patterned second photoresist layer. Micro-ditches are formed because of inaccuracy, so the process window can be larger than the conventional method, and this importance is even more prominent in sub-micron technology. Employees ’Consumption, Intellectual Property Bureau, Ministry of Economic Affairs In summary, although the present invention has been disclosed in the preferred embodiment as above, it is not intended to limit the present invention. Any person skilled in the art can make the present invention without departing from the spirit and scope of the present invention. Various changes and retouching, so the protection scope of the present invention shall be determined by the scope of the attached patent application. This paper size applies the Chinese National Standard (CNS) Λ4 specification (210 × 297 mm)