200933811 16 2597ltwf.doc/n 九、發明說明： 【發明所屬之技術領域】 本發明是有關於一種隔離結構及其製造方法，且特別 是有關於一種淺溝渠隔離結構及其製造方法。 【先前技術】 隨著半導體技術的進步，元件的尺寸不斷地縮 ❹ 小，而進入深次微米（deep submicron meter)的領域中， 甚至更細微的尺寸範圍。因此，為了防止相鄰的元件發 . 生短路的現象，元件與元件間的隔離變得相當重要。現今 較常使用的隔離方法為淺溝渠隔離結構(shallow trench isolation ’ STI)製程。利用此技術所形成的隔離區具有可調 整大小（scalable)的優點，並且可避免傳統局部區域氧化 (LOCOS)法隔離技術中鳥嘴侵蝕的缺點，因此，對於現今 的金氧半導體(metal oxide semiconductor，MOS)製程而 言’是一種較為理想的隔離技術。 ® 圖1是習知一種淺溝渠隔離結構的剖面示意圖。請參 “'、圖1，習知淺溝渠隔離結構的製造方法是先在基底1〇〇 上依序形成罩幕層（未繪示)與墊氧化層（未緣示），而後圖案 化罩幕層與塾氧化層，並於基底100中形成溝渠1〇8，接 著以絕緣層110填滿溝渠108，再將罩幕層與墊氧化層移 除以形成淺溝渠隔離結構112。然而，由於絕緣層 的材質與塾氧化層的材質均為氧化石夕， ，程中，以及在後續的各項製程二 所使用的氫氟酸蝕刻液也會侵蝕溝渠1〇8邊角處114的絕 5 16 25971twf.doc/n 200933811 緣層110,而造成溝渠108的邊角114處外露，並產生凹 陷(divot)l〗6。此外，在形成淺溝渠隔離結構112之後，由 於後續會進行多次的清洗步驟，而清洗步驟所使用的氫氟 酸或磷酸清洗溶液也會發生同樣的情形。因此，前述方法 所製作的淺溝渠隔離結構容易產生漏電流，而造成元件間 短路。此外，在凹陷116處會累積電荷，而造成元件的次 啟始漏電流(sub-threshold leakage current)，產生所謂的頸 結效應(kink effect)或是閘極誘導汲極漏電(gate induced drain leakage，GIDL)效應，進而使得元件的可靠度與良率 降低。 【發明内容】 本發明提供一種淺溝渠隔離結構的製造方法，可以避 免在淺溝渠隔離結構的邊角處產生凹陷，進而防止導致元 件漏電流的情況發生。 本發明另提供一種淺溝渠隔離結構，玎以有效地進行 〇 隔離’以防止各元件之間發生短路。 本發明提出一種淺溝渠隔離結構的製造方法。首先， 於基底上依序形成墊氧化層與罩幕層。然後，圖案化罩幕 層與墊氧化層，並於基底中形成溝渠。接著，於溝渠中形 成第一襯層。然後，移除部份第一襯層，以至少暴露出溝 渠的邊角。而後，於基底上形成第二襯層，第二襯層覆蓋 溝渠的邊角與第一襯層，此第二襯層的材質與第一襯層的 材貝不同。繼而，於基底上形成絕緣層以填滿溝渠。接著， 移除溝渠外的絕緣層、第二襯層、罩幕層以及墊氧化層。 6 200933811 26 25971twf.doc/n 方法Ϊ據實施例所述’上述淺溝渠隔離結構的製造 忐中，上述第一襯層的材質包括氧化矽。 依據本發明實施例所述，上述漤 方法Φ 〜w #錢離結構的製造 中，上述形成第一襯層的方法包括熱氧化法。 方法t據本發明實施例所述，上述淺溝渠隔離結構的製造 r, 上料—襯層的材質包括氣碳彳U>(SiCN)、氧破 〇 (Si〇N)iro) ^ ^'b^(SiQ ' ^ 依據本發明實_所述’上錢輕祕結構的製造 法中，上述形成第二襯層的方法包括原子層沉積法。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 法中，上述形成第二襯層的方法包括化學氣相沉積法。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 法中，上述第二概層的材質與塾氧化層的材質不同。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中’上述第二襯層的材質與罩幕層的材質不同。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中’上述第二襯層的材質與絕緣層的材質不同。 依據本發明實施例所述’上述淺溝渠隔離結構的製造 方法中’上述移除部份第一襯層的方法包括非等向性蝕刻 法。 依據本發明實施例所述’上述淺溝渠隔離結構的製造 方法中’上述移除部份第一襯層的步驟更包括移除罩幕層 的邊角。 7 126 25971twf.doc/n 200933811 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中，上述移除部份第一襯層的步驟更包括暴露出溝渠 的底部。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中，上述移除溝渠外的絕緣層與移除溝渠外的第二襯 層之步驟係同時進行。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中，上述移除溝渠外的絕緣層與移除溝渠外的第二襯 層之步驟係以罩幕層為移除終止層。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中，上述移除溝渠外的絕緣層與移除溝渠外的第二襯 層的方法包括化學機械研磨法。 依據本發明實施例所述，上述淺溝渠隔離結構的製造 方法中，墊氧化層是以蝕刻液移除，其對於第二襯層之蝕 刻率低於塾氧化層者。 本發明另提出一種淺溝渠隔離結構，配置於基底的溝 渠中，其包括第一概層、第二概層以及絕緣層。第一概層 配置於溝渠的侧壁，其高度低於基底之表面，至少暴露出 溝渠的邊角。第二襯層覆蓋於溝渠的邊角與第一襯層，其 材質與第一襯層的材質不同。絕緣層則配置於第二襯層 上’填滿溝渠。 依據本發明實施例所述，上述淺溝渠隔離結構中，上 述第二襯層的材質與絕緣層的材質不同。 依據本發明實施例所述，上述淺溝渠隔離結構中，上 8 200933811 16 25971twf.doc/n 述第一襯層的材質包括氧化矽。 依據本發明實施例所述，上述淺溝渠隔離結構中，上 述第二襯層的材質包括氮碳化矽（SiCN)、氧碳化石夕 (sico)、碳化石卿〇、碳氮化啊SicC)N)、氮氧化哪 或介電常數大於4之高介電常數材料。 ❹ 本發明因在溝渠的邊角形成第二襯層，因此在移除塾 氧化層以及進行清洗製_，能髓淺溝渠隔離結構的邊 角不受_液或清洗溶液的破壞，崎免錢溝渠隔離姓 構的邊祕產生㈣。因此，本發·有效地提升隔離^ 力，P方止漏電流的情況出現，纽避免在各元件之間發生 短路，進而提升元件的可靠度與良率。 為讓本發明之上述特徵和優點能更明顯易懂，下文特 舉較佳實施例’並配合所_式，作詳細說明如下。 【實施方式】 圖2A至圖2E是依照本發明實施例所纷示之一種淺 溝渠隔離結構的製造流程剖面圖。200933811 16 2597ltwf.doc/n IX. Description of the Invention: [Technical Field] The present invention relates to an isolation structure and a method of fabricating the same, and more particularly to a shallow trench isolation structure and a method of fabricating the same. [Prior Art] With the advancement of semiconductor technology, the size of components has been steadily shrinking, and into the field of deep submicron meters, even more subtle size ranges. Therefore, in order to prevent adjacent components from being short-circuited, isolation between components and components becomes quite important. The more commonly used isolation method today is the shallow trench isolation (STI) process. The isolation region formed by this technology has the advantage of being scalable, and can avoid the disadvantage of bird's mouth erosion in the traditional local area oxidation (LOCOS) isolation technology. Therefore, for today's metal oxide semiconductor (metal oxide semiconductor) , MOS) process is 'an ideal isolation technology. ® Figure 1 is a schematic cross-sectional view of a conventional shallow trench isolation structure. Please refer to "', Figure 1, the conventional shallow trench isolation structure is manufactured by first forming a mask layer (not shown) and a pad oxide layer on the substrate 1 (not shown), and then patterning the mask The curtain layer and the tantalum oxide layer form a trench 1〇8 in the substrate 100, then fill the trench 108 with the insulating layer 110, and then remove the mask layer and the pad oxide layer to form the shallow trench isolation structure 112. However, The material of the insulating layer and the material of the tantalum oxide layer are both oxidized stone, the process, and the hydrofluoric acid etching solution used in the subsequent processes 2 will also erode the edge of the trench 1〇8. 16 25971twf.doc/n 200933811 The edge layer 110 causes the corners 114 of the trench 108 to be exposed, and a divot is formed. Further, after the shallow trench isolation structure 112 is formed, it is subsequently performed multiple times. The same is true for the cleaning step, and the hydrofluoric acid or phosphoric acid cleaning solution used in the cleaning step. Therefore, the shallow trench isolation structure fabricated by the above method is prone to leakage current and short circuit between components. Further, in the recess 116 Will accumulate charge, and The sub-threshold leakage current of the component causes a so-called kink effect or a gate induced drain leakage (GIDL) effect, thereby making the reliability of the component The invention provides a method for manufacturing a shallow trench isolation structure, which can avoid the occurrence of a depression at the corners of the shallow trench isolation structure, thereby preventing the leakage current of the component from occurring. The present invention further provides a The shallow trench isolation structure is configured to effectively perform the germanium isolation to prevent short circuits between the components. The present invention provides a method for fabricating a shallow trench isolation structure. First, a pad oxide layer and a mask layer are sequentially formed on the substrate. Then, the mask layer and the pad oxide layer are patterned, and a trench is formed in the substrate. Then, a first liner layer is formed in the trench. Then, a portion of the first liner layer is removed to expose at least the corners of the trench. Then, a second lining layer is formed on the substrate, the second lining layer covers the corner of the trench and the first lining layer, and the material of the second lining layer and the first lining layer The material is different. Then, an insulating layer is formed on the substrate to fill the trench. Then, the insulating layer, the second liner layer, the mask layer and the pad oxide layer outside the trench are removed. 6 200933811 26 25971twf.doc/n MethodΪ According to the manufacturing process of the above-mentioned shallow trench isolation structure, the material of the first liner layer includes ruthenium oxide. According to the embodiment of the present invention, in the manufacture of the 漤 method Φ 〜 w #钱离结构, the above The method for forming the first lining layer comprises a thermal oxidation method. Method t According to the embodiment of the present invention, the preparation of the shallow trench isolation structure, the material of the lining-liner comprises a gas-carbon 彳U> (SiCN), and the oxygen is broken. 〇(Si〇N)iro) ^ ^'b^(SiQ ' ^ According to the manufacturing method of the invention, the method for forming the second underlayer includes the atomic layer deposition method. According to an embodiment of the present invention, in the method of fabricating the shallow trench isolation structure, the method of forming the second liner includes a chemical vapor deposition method. According to the manufacturing method of the shallow trench isolation structure, the material of the second layer is different from the material of the tantalum oxide layer. According to the embodiment of the present invention, in the manufacturing method of the shallow trench isolation structure, the material of the second liner layer is different from the material of the mask layer. According to the embodiment of the present invention, in the manufacturing method of the shallow trench isolation structure, the material of the second liner layer is different from the material of the insulating layer. In the above method for fabricating a shallow trench isolation structure according to an embodiment of the present invention, the method of removing a portion of the first liner layer includes an anisotropic etching method. In the above method of fabricating the shallow trench isolation structure according to the embodiment of the present invention, the step of removing the portion of the first liner further comprises removing the corners of the mask layer. In the manufacturing method of the shallow trench isolation structure, the step of removing a portion of the first liner further comprises exposing the bottom of the trench. According to an embodiment of the present invention, in the manufacturing method of the shallow trench isolation structure, the step of removing the insulating layer outside the trench and the step of removing the second liner outside the trench are performed simultaneously. According to the embodiment of the present invention, in the manufacturing method of the shallow trench isolation structure, the step of removing the insulating layer outside the trench and removing the second liner outside the trench is to remove the termination layer by using the mask layer. According to an embodiment of the present invention, in the method for fabricating the shallow trench isolation structure, the method of removing the insulating layer outside the trench and removing the second liner outside the trench includes a chemical mechanical polishing method. According to an embodiment of the invention, in the method for fabricating the shallow trench isolation structure, the pad oxide layer is removed by an etchant, and the etch rate of the second liner is lower than that of the tantalum oxide layer. The invention further provides a shallow trench isolation structure disposed in the trench of the substrate, comprising a first layer, a second layer and an insulating layer. The first layer is disposed on the side wall of the trench and has a height lower than the surface of the substrate to expose at least the corner of the trench. The second lining covers the corners of the trench and the first lining, and the material is different from the material of the first lining. The insulating layer is disposed on the second liner to fill the trench. According to the embodiment of the present invention, in the shallow trench isolation structure, the material of the second liner layer is different from the material of the insulation layer. According to the embodiment of the present invention, in the shallow trench isolation structure, the material of the first liner includes yttrium oxide. According to the embodiment of the present invention, in the shallow trench isolation structure, the material of the second liner layer includes niobium oxynitride (SiCN), oxycarbonized carbon sic, carbon carbide, and carbonic acid (SicC)N. ), a high dielectric constant material with a nitrogen oxidation or a dielectric constant greater than 4. ❹ The present invention forms a second lining layer at the corners of the trench, so that the yttrium oxide layer is removed and the cleaning process is performed _, the corners of the shallow trench isolation structure are not damaged by the _ liquid or the cleaning solution, and the money is free. The secret of the ditch isolation of the surname (4). Therefore, the present invention effectively improves the isolation force, and the P-side leakage current occurs, so that the short circuit between the components is avoided, thereby improving the reliability and yield of the component. In order to make the above features and advantages of the present invention more comprehensible, the preferred embodiments of the present invention are described in detail below. [Embodiment] Figs. 2A to 2E are cross-sectional views showing a manufacturing process of a shallow trench isolation structure according to an embodiment of the present invention.
首先’請參照圖2A，於基底2〇〇上依序形成塾氧化層 202與罩幕層2G4。基底綱例如是p型摻_基底、N 型掺雜縣底、|晶錄底、_化鎵基底、磷化銦基底或 石夕化鍺基底。墊氧化層2G2的材f例如是氧化♦，其形成 方法例如是熱氧化法或化學氣相沈積法。罩幕層2〇4的材 質例如是1化梦，其形成方法例如是化學氣相沈積法。 然後’請參照圖2B，圖案化罩幕層綱與塾氧化層 200933811 ------— IS 25971twf.doc/n 202，並於基底200中形成溝渠206。在一實施例中，是進 行微影與蝕刻製程，以形成圖案化的罩幕層2〇4。而後， 以圖案化的罩幕層204為蝕刻罩幕，蝕刻墊氧化層2〇2與 部伤的基底200，以在基底2〇〇中形成溝渠206。 然後，請參照圖2C’於溝渠2〇6中形成第一襯層208。 第-襯層208的材質例如是氧化妙，其形成方法例如是熱 氧化法。然後，移除部份第一襯層2〇8，使其高度低於基 ❹ 底20〇的表面200a，以暴露出溝渠20ό的邊角210。移除 的方法包括非等向性蝕刻法，例如是乾式蝕刻製程。於本 實施例中，移除部份第一襯層2〇8的過程中，除了會暴露 出溝渠206的邊角210外’也可以暴露出溝渠2〇6的底部， 再者，在這個步驟中，也可能會移除罩幕層2〇4的邊角， 如圖2Β所示者。罩幕層2〇4的邊角2〇4a移除後，將有助 於後續溝渠206之填溝的進行。 而後，於基底200上形成第二襯層212，第二襯層212 覆蓋溝渠206的邊角210與第一襯層2〇8。第二襯層212 的材質為介電材料，其材質與第一襯層2〇8、墊氧化層2〇2 以及罩幕層204的材質均不相同。第二襯層212的材質例 如是氣碳化矽(SiCN)、氧碳化、碳化矽(Sic)、碳 氛化石夕(SiCON)、氮氧化矽(Si〇N)4介電常數大於*之高 介電常數材例如是Ta2〇5、HfSi02、HfSiON等，其形成方 法例如是原子層沉積法或化學氣相沉積法。 繼而，請參照圖2D，於基底200上形成絕緣層214， 以填滿溝渠206。絕緣層214的材質與第二襯層212的材 26 25971twf.doc/n 200933811 質不同。絕緣層214的材質例如是氧化矽，其形成方法例 如是電漿增強型化學氣相法(PECVD)、常壓化學氣相沉積 法(APCVD)或高密度電漿化學氣相沉積法(HDPCVD)或次 大氣壓化學氣相沈積法(SACVD)。 接著，請參照圖2E，移除溝渠206外的絕緣層214、 第二襯層212、罩幕層204以及墊氧化層202。在一實施例 中，是以罩幕層204為移除終止層，移除部份絕緣層214 〇 與部份第二襯層212。移除絕緣層214與第二襯層212的 方法例如是化學機械研磨法。而後，移除罩幕層2〇4以及 墊氧化層202,以於基底200中形成淺溝渠隔離結構216。 移除罩幕層204的方法包括進行濕式蝕刻製程，例如是以 熱磷酸作為蝕刻液。移除墊氧化層2〇2的方法包括進行濕 式#刻裝程，例如是使用氫氟酸作為韻刻液。 方法例如疋化學機械研磨法。而後，移除$ 二襯層212、罩幕層204以及墊氧化層2〇2 在另-實施例中，是以罩幕層2〇4上的第二概層212 為移除終止層’移除部份絕緣層214。移除絕緣層214的 中形成淺溝渠隔離結構216。移除溝渠2G6外的第二襯層 加的方法例如7C乾式或濕式钱刻法。關於移除罩幕層綱 與墊氧化層202的方法可參考前面實施例的 贅述。 你个First, referring to Fig. 2A, a tantalum oxide layer 202 and a mask layer 2G4 are sequentially formed on the substrate 2''. The substrate class is, for example, a p-type doped-based substrate, an N-type doped county bottom, a crystal substrate, a gallium substrate, an indium phosphide substrate, or a Shihua chemical substrate. The material f of the pad oxide layer 2G2 is, for example, oxidized ♦, which is formed by, for example, thermal oxidation or chemical vapor deposition. The material of the mask layer 2〇4 is, for example, a dream, and its formation method is, for example, a chemical vapor deposition method. Then, please refer to FIG. 2B, patterning the mask layer and the germanium oxide layer 200933811 ------- IS 25971 twf.doc/n 202, and forming a trench 206 in the substrate 200. In one embodiment, a lithography and etching process is performed to form a patterned mask layer 2〇4. Thereafter, the patterned mask layer 204 is used as an etch mask to etch the pad oxide layer 2〇2 and the damaged substrate 200 to form trenches 206 in the substrate 2〇〇. Then, a first liner layer 208 is formed in the trench 2〇6 with reference to Fig. 2C'. The material of the first underlayer 208 is, for example, oxidized, and its formation method is, for example, a thermal oxidation method. Then, a portion of the first underlayer 2 〇 8 is removed to a height lower than the surface 200a of the base 〇 20 以 to expose the corner 210 of the trench 20 。. The method of removal includes an anisotropic etch, such as a dry etch process. In this embodiment, in the process of removing a portion of the first lining layer 2〇8, in addition to exposing the corners 210 of the trench 206, the bottom of the trench 2〇6 may also be exposed, and further, in this step. In the middle, it is also possible to remove the corners of the mask layer 2〇4, as shown in Fig. 2Β. The removal of the corner 2〇4a of the mask layer 2〇4 will facilitate the filling of the subsequent trench 206. Then, a second liner 212 is formed on the substrate 200, and the second liner 212 covers the corner 210 of the trench 206 and the first liner 2〇8. The material of the second liner 212 is a dielectric material, and the material of the second liner 212 is different from that of the first liner 2〇8, the pad oxide layer 2〇2, and the mask layer 204. The material of the second lining layer 212 is, for example, carbon monoxide (SiCN), oxycarburization, strontium carbide (Sic), carbonized fossil (SiCON), yttrium oxynitride (Si〇N) 4 and a dielectric constant greater than * The electric constant material is, for example, Ta2〇5, HfSiO2, HfSiON or the like, and the formation method thereof is, for example, atomic layer deposition method or chemical vapor deposition method. Then, referring to FIG. 2D, an insulating layer 214 is formed on the substrate 200 to fill the trench 206. The material of the insulating layer 214 is different from the material of the second liner 212 26 25971 twf.doc/n 200933811. The material of the insulating layer 214 is, for example, cerium oxide, and the forming method thereof is, for example, plasma enhanced chemical vapor deposition (PECVD), atmospheric pressure chemical vapor deposition (APCVD) or high density plasma chemical vapor deposition (HDPCVD). Or sub-atmospheric chemical vapor deposition (SACVD). Next, referring to FIG. 2E, the insulating layer 214, the second liner 212, the mask layer 204, and the pad oxide layer 202 outside the trench 206 are removed. In one embodiment, the mask layer 204 is removed from the termination layer, and a portion of the insulating layer 214 and a portion of the second liner 212 are removed. The method of removing the insulating layer 214 and the second liner 212 is, for example, a chemical mechanical polishing method. The mask layer 2〇4 and the pad oxide layer 202 are then removed to form a shallow trench isolation structure 216 in the substrate 200. The method of removing the mask layer 204 includes performing a wet etching process, such as using hot phosphoric acid as an etchant. The method of removing the pad oxide layer 2〇2 includes performing a wet type engraving process, for example, using hydrofluoric acid as a rhyme. Methods such as hydrazine chemical mechanical milling. Then, the second liner 212, the mask layer 204, and the pad oxide layer 2〇2 are removed. In another embodiment, the second layer 212 on the mask layer 2〇4 is removed as a removal layer. Except for a portion of the insulating layer 214. The shallow trench isolation structure 216 is formed in the middle of the insulating layer 214. A method of removing the second liner outside the trench 2G6 is, for example, a 7C dry or wet method. For a method of removing the mask layer and the pad oxide layer 202, reference may be made to the description of the previous embodiment. You
移除溝渠206外的第 I 202 ’以於基底200 a町何買興罩幕層204 ，且其對於移除罩幕層 11 200933811 25971twf.doc/n 204以及墊氧化層2〇2的過程中所使用的蝕刻液，均具有 極咼的選擇性，也就是，這些蝕刻液對於第二襯層212之 钱刻率低於墊氧化層202且低於罩幕層204，因此，第二 觀層212可以保濩淺溝渠隔離結構216，使其不會遭受餘 刻液的破壞。故，淺溝渠隔離結構216的邊角21〇a處不會 有凹陷的形成。 ❹ Ο 此外，在形成淺溝渠隔離結構216以後，為了去除後 ，製程在基底200表面所產生的殘留物，還可能包含著多 夂的/月洗製程。而在這些清洗製程中所使用的清洗液，例 ^是使用氫氟酸與磷酸’其對於第二襯層犯同樣具有極 ^的選擇性，因此，淺溝渠隔離結構加的邊角21〇a可被 第一=層212保護’而不會有凹陷的形成。 ”述’本發明以第二襯層覆蓋於溝渠的邊角，因 的邊角，化層或清洗製程時，淺溝渠隔離結構 θ被蝕刻液或清洗液所侵蝕而產生凹陷，故， 間::::離===’進而防止漏電流或是元件 除罩幕層的邊由，除部份第—襯層的同時也會移 效能。因此，本發助於輕的溝填’啸升隔離的 雖梦士 1發月月b提升70件的可靠度與良率。 限定本發明，佳實施例揭露如上1其並非用以 脫離本發明之精領；中具有通常知識者’在不 因此本發明之it内，當可作些許之更動與潤飾， 當視後社申請專利範_界定 12 200933811 26 25971 twf.doc/n 【圖式簡單說明】 圖1是習知一種淺溝渠隔離結構的剖面示意圖。 圖2A至圖2E是依照本發明實施例所繪示之一種淺溝 渠隔離結構的製造流程剖面圖。 【主要元件符號說明】 100 :基底 108 :溝渠 110 :絕緣層 112 :淺溝渠隔離結構 114 :邊角 116 :凹陷 200 :基底 200a :表面 202 :墊氧化層 204 :罩幕層 204a :邊角 206 :溝渠 208 :第一襯層 210、210a :邊角 212 :第二襯層 214 :絕緣層 216 :淺溝渠隔離結構 13The first 202' outside the trench 206 is removed to cover the substrate 200a, and it is in the process of removing the mask layer 11 200933811 25971twf.doc/n 204 and the pad oxide layer 2〇2. The etching solutions used are all extremely selective, that is, the etching rate of the etching liquid for the second liner 212 is lower than the pad oxide layer 202 and lower than the mask layer 204, and therefore, the second layer 212 can protect the shallow trench isolation structure 216 from damage caused by the residual liquid. Therefore, there is no depression at the corner 21〇a of the shallow trench isolation structure 216. ❹ Ο In addition, after the shallow trench isolation structure 216 is formed, in order to remove, the residue generated on the surface of the substrate 200 may also contain a multi-turn/month wash process. In the cleaning process used in these cleaning processes, the use of hydrofluoric acid and phosphoric acid is also extremely selective for the second liner. Therefore, the corners of the shallow trench isolation structure are 21 〇a. It can be protected by the first = layer 212 without the formation of depressions. According to the present invention, the second lining layer covers the corners of the ditch, and the shallow trench isolation structure θ is eroded by the etching liquid or the cleaning liquid to cause a depression due to the corner, the layer or the cleaning process, so that: ::: From ===' to prevent leakage current or component removal of the edge of the mask layer, in addition to some of the first layer of the liner will also shift the performance. Therefore, the help of light trench filling 'howling The isolation of the dreamer 1 month month b increases the reliability and yield of 70 pieces. Limiting the invention, the preferred embodiment discloses that the above 1 is not used to deviate from the essence of the invention; In the present invention, when a little change and retouching can be made, the company will apply for a patent model _definition 12 200933811 26 25971 twf.doc/n [Simplified Schematic] FIG. 1 is a conventional shallow trench isolation structure. 2A to 2E are cross-sectional views showing a manufacturing process of a shallow trench isolation structure according to an embodiment of the invention. [Main component symbol description] 100: substrate 108: trench 110: insulating layer 112: shallow trench isolation Structure 114: corner 116: recess 200: substrate 200a : Surface 202 : pad oxide layer 204 : mask layer 204a : corner 206 : trench 208 : first liner 210 , 210a : corner 212 : second liner 214 : insulating layer 216 : shallow trench isolation structure 13