201116475 六、發明說明： 【發明所屬之技術領威】 本發明係，-種微機電系統結構及其製造方法。特定 言之，本發_關於4具有立體振膜電極之微機電系統結 構及其製造料。此等立_膜電極具有複合結構’以增進 立體振膜電極本身之機械強度。 【先前技術】 MEMS裝置包括具有微機電的基板與微電子電路整合 在一起。此種裝置可形成例如微感應器（microsensors)或微驅 動器（microactuators)，其係基於例如電磁、電致伸縮 (electrostrictive)、熱電、塵電、廢阻(piezoresistive)等效應來 操作。MEMS裝置可藉由微電子技術例如微影、氣相沉積、 及蝕刻等，於絕緣層或其他之基板上製得。近來，有使用與 習知之類比及數位CMOS (互補式金氧半）電路之同類型的製 造步驟(例如材料層的沉積與材料層的選擇性移除）來製造 MEMt目前微機電㈣麥克風結構可藉由―般的微電子技 術例如微影、氣相沉積、_ ’或光刻電禱模造(liga)等技 術，於絕緣層或其他半導體等之基板上製得。 請參考第1圖至第3m圖至ΪΓ圖為習知製造微 機電系統麥克風結構之方法示意圖。如第1圖鮮，習知製 造具多層振叙微機電系齡克風結構H)之方法係、先提供 201116475 一基底12,且基底12之表面包含有一基部犧牲層14以及一 第-金腳16。然後，圖案化第一金屬層16以形成一第一 微型金屬網18。接著，如第2圖所示，將一第一犧牲層2〇 覆蓋於基底12上，並且平坦化第—犧牲層2()之表面。然後， 於第-犧牲層2G上形成-第二金屬層22，再圖案化第二金 制22以形成第二微型金屬網。接著，將—第二犧牲層％ 覆蓋於基底12上’並且平垣化第二犧牲層％之表面。然後， 於弟二犧牲層26上形成一第三金屬層28，再圖案化第三金 屬層28以形成第三微型金屬網。之後，覆蓋一第三犧牲層 32於基底12上。 最後如第3圖所示，利用一等向性姓刻製程移除第_ ㈣金屬網18、第二微型金屬網以及第三微型金屬網之間白 弟-犧牲層20、第二犧牲層％、第三犧牲層&以及部分』 ;犧=二使第一微型金屬網18、第二微型金屬網以』 型金屬網懸浮於基底12上，而形成多層振膜結構。 可進行背後_製程，將基底12_，使外界之空 =子可上下的自由縣，進而震動多層 形成習知微機W齡絲轉1G。 至此巧 般』: = 胸機電系統麥克風結構係採用- 構成之Z第:Γ1Τ微型金屬網’即先形成㈣ 層圖案化。接層二塗·層’且將光-201116475 VI. Description of the Invention: [Technology Leading to the Invention] The present invention is a MEMS structure and a method of manufacturing the same. Specifically, the present invention relates to a microelectromechanical system structure having a stereoscopic diaphragm electrode and a material for its manufacture. These vertical membrane electrodes have a composite structure to enhance the mechanical strength of the stereomembrane electrode itself. [Prior Art] A MEMS device includes a substrate having microelectromechanics integrated with a microelectronic circuit. Such devices may form, for example, microsensors or microactuators that operate based on effects such as electromagnetic, electrostrictive, thermoelectric, dust, piezoresistive, and the like. MEMS devices can be fabricated on insulating layers or other substrates by microelectronics such as lithography, vapor deposition, and etching. Recently, there are similar types of fabrication steps (such as deposition of material layers and selective removal of material layers) using conventional analog-to-digital and digital CMOS (complementary MOS) circuits to fabricate MEMt's current MEMS (tetra) microphone structure. It is fabricated on a substrate such as an insulating layer or other semiconductor by a general microelectronic technique such as lithography, vapor deposition, or photolithography. Please refer to Fig. 1 to Fig. 3m to Fig. 3 for a schematic diagram of a conventional method for fabricating a microphone structure of a MEMS system. As shown in FIG. 1 , a method for fabricating a multi-layered vibrating micro-electromechanical system of the wind structure H) is provided. First, a substrate 12 is provided in 201116475, and the surface of the substrate 12 includes a base sacrificial layer 14 and a first-golden foot. 16. The first metal layer 16 is then patterned to form a first micro-metal mesh 18. Next, as shown in Fig. 2, a first sacrificial layer 2 is covered on the substrate 12, and the surface of the sacrificial layer 2 is planarized. Then, a second metal layer 22 is formed on the first sacrificial layer 2G, and the second metal 22 is patterned to form a second micro metal mesh. Next, the second sacrificial layer % is overlaid on the substrate 12' and the surface of the second sacrificial layer % is flattened. Then, a third metal layer 28 is formed on the sacrificial layer 26, and the third metal layer 28 is patterned to form a third micrometal mesh. Thereafter, a third sacrificial layer 32 is overlaid on the substrate 12. Finally, as shown in FIG. 3, the ante (four) metal mesh 18, the second micro metal mesh, and the third micro metal mesh are removed by an isotropic process to remove the white-sacrificial layer 20 and the second sacrificial layer. The third sacrificial layer & and the portion of the first micro-metal mesh 18 and the second micro-metal mesh are suspended on the substrate 12 by a stencil, thereby forming a multi-layered diaphragm structure. Can carry out the back_process, the base 12_, the outer space = the sub-free can be up and down, and then shake the multi-layer to form a conventional microcomputer W-age wire to 1G. At this point in time: = The structure of the microphone system of the chest electromechanical system is adopted - the Z-shaped: Γ1Τ micro-metal mesh is formed first (four) layer patterning. Layer 2 coating layer 'and will light-
步❹ 再關案域阻層為遮罩_金屬層，以A 夕所需之各層微型金屬網。由於以上方法需錢刻多= 201116475 金屬層，所以仍然需要一種新穎的微機電系統結構，而具有 更簡化但是依然強固之結構。 【發明内容】 本發明於是提出-種微機電系統結構，其可作為麥克風 之用。本發明之微機㈣統結構，具有複合 電極。此等具諸合結狀讀振膜電極，不㈣ #強度’而且在製作時還可以無需進行金屬層的_步驟，於 是製作流程得以更為簡化。 、 本發明所提出之微機電系統結構，包含—背板電極與一 立體振膜電極。立體振膜電極鄰近f板電極，而—起步成一 :變電容。立體賴電極包含具有至少1槽結構之第一: 屬層、位於凹槽結構之側壁上之至少—第、以pStep ❹ Re-secured the domain barrier layer as a mask _ metal layer, to the layer of micro metal mesh required for A eve. Since the above method requires more than the 201116475 metal layer, there is still a need for a novel MEMS structure with a more simplified but still robust structure. SUMMARY OF THE INVENTION The present invention thus proposes a MEMS structure that can be used as a microphone. The microcomputer (four) structure of the present invention has a composite electrode. These have a closed-type read diaphragm electrode, which is not (four) #strength' and can be fabricated without the need for a metal layer step, so that the manufacturing process is simplified. The MEMS structure proposed by the present invention comprises a back plate electrode and a stereo diaphragm electrode. The stereo diaphragm electrode is adjacent to the f-plate electrode, and starts to become a variable capacitor. The stereoscopic electrode includes a first structure having at least one groove structure: a genus layer, at least a side of the sidewall of the groove structure, and a p
立於第—金屬層與第—間隙壁上之第二金屬層。立體振 ，電極之複合結構可以增進立體振膜電極本身之機械強 又’而足以應付當麥克風在使用時，聲 壓縮或是伸張應力。 輯產生之各種 提供I! 電系統結構的方法。首先， 煶供-基材，其包含一具有斜角之溝渠 層共形地覆蓋基材。然後，進行以一材料 之誉_ 餘刻步驟’移除部份 ^弟一材料層而選擇性地保留斜角溝渠側壁上之第 層，以形成第一間隙壁。繼續，以第一 4 金屬層共形地覆蓋在 _壁上。再來，將第二材料層共形地覆蓋第— 201116475 金屬層。之後，進行一第二蝕刻步驟，移除部份之第二材料 層，但選擇性地保留鄰近斜角溝渠側壁上之第二材料層，以 形成第二間隙壁。接下來，將第二金屬層共形地覆蓋在第二 間隙壁與第一金屬層上，於是形成了立體振膜電極。 在本發明立體振膜電極中，一介電層選擇性地位於兩金 屬層之間，而形成一複合結構。此等具有複合結構之立體振 膜電極，不但具有足以應付當麥克風在使用時，聲波震動所 產生之各種壓縮或是伸張應力之高機械強度，而且製作步驟 還無涉於金屬層的蝕刻步驟，因之又同時具有製作流程得以 更為簡化之優點。 【實施方式】 本發明首先提供一種形成微機電系統結構的方法。第4 圖至第12圖例示製造本發明微機電系統結構之一實施方法 示意圖。本發明形成微機電系統結構的方法，如第4圖所示， 首先提供基材201。基材201可以為一種含矽的材料，例如 單晶矽、多晶矽、氧化矽或其組合。使用半導體基材可以使 得本發明製作微機電系統結構的方法，與一般半導體之製作 流程相容，其為本發明形成微機電系統結構方法的特點之 一。基材201又包含一溝渠202。在形成溝渠202時，可以 選擇適當之蝕刻方式，使得溝渠202之底部與側璧會具有大 於90度之斜角α。例如斜角溝渠202之斜角α介於100-135 度之間。 201116475 其次，如第5圖所示’使用第一材料層2l〇 住基材201。第一材料層210可以為一介電材料，例如盖 矽、氮化矽、氮氧化矽或碳化矽之至少一者。或者，氣化 料層210可以具有一複合結構’例如包含氧化發、材 氮氧化矽及/或碳化矽之複合結構，其經由分別之^ 石夕、 "匕積與餘刻 所形成。 ^ 然後，請同時參考第5圖與第6圖，進行第—^ 禾次之蝕刻a second metal layer standing on the first metal layer and the first spacer. The three-dimensional vibration and the composite structure of the electrodes can enhance the mechanical strength of the stereoscopic diaphragm electrode itself and are sufficient to cope with the acoustic compression or tensile stress when the microphone is in use. Various methods of generating I! Electrical system structures. First, a donor-substrate comprising a layer of beveled corners conformally covers the substrate. Then, the first layer on the side wall of the beveled trench is selectively removed by removing the portion of the material layer by a material _ residual step to form the first spacer. Continuing, the first 4 metal layers are conformally covered on the _ wall. Further, the second material layer conformally covers the -201116475 metal layer. Thereafter, a second etching step is performed to remove a portion of the second material layer, but selectively retain a second material layer adjacent the sidewall of the bevel trench to form a second spacer. Next, the second metal layer is conformally covered on the second spacer and the first metal layer, thereby forming a stereo diaphragm electrode. In the stereomembrane electrode of the present invention, a dielectric layer is selectively positioned between the two metal layers to form a composite structure. These three-dimensional diaphragm electrodes having a composite structure not only have high mechanical strength enough to cope with various compression or tensile stresses generated by acoustic vibration when the microphone is in use, but also the etching step of the metal layer is not involved in the fabrication steps. At the same time, it has the advantage of simplifying the production process. [Embodiment] The present invention first provides a method of forming a structure of a microelectromechanical system. 4 to 12 are schematic views showing an embodiment of a method of fabricating the MEMS structure of the present invention. The method of forming a MEMS structure of the present invention, as shown in Fig. 4, first provides a substrate 201. Substrate 201 can be a germanium containing material such as single crystal germanium, polycrystalline germanium, cerium oxide or combinations thereof. The use of a semiconductor substrate allows the method of fabricating a MEMS structure of the present invention to be compatible with the fabrication process of a general semiconductor, which is one of the features of the method of forming a MEMS structure of the present invention. Substrate 201 further includes a trench 202. When the trench 202 is formed, an appropriate etching method can be selected such that the bottom and side turns of the trench 202 have an oblique angle α greater than 90 degrees. For example, the bevel angle a of the beveled trench 202 is between 100 and 135 degrees. 201116475 Next, as shown in Fig. 5, the substrate 201 is held by the first material layer 2l. The first material layer 210 may be a dielectric material such as at least one of a cap, a tantalum nitride, a hafnium oxynitride or a tantalum carbide. Alternatively, the gasification layer 210 may have a composite structure, e.g., a composite structure comprising oxidized hair, bismuth oxynitride, and/or tantalum carbide, which is formed by separate "hoarding" and residual. ^ Then, please refer to the 5th and 6th drawings at the same time, and perform the etching of the first ^^
材料 步驟，例如一乾#刻步驟。第一次之蚀刻步驟，較佳者I 量移除第一材料層210之水平部分211，但又保留第 曰盡 層210部分之垂直部分212’亦即位於斜角溝渠2〇2側壁 上之第一材料層210。於是第一材料層210部分之垂直邛八 212便成為第一間隙壁213。 繼續’如第7圖所示’將第一金屬層220共形地覆蓋在 基材201與第一間隙壁213之上。第一金屬層220可以包含 紹、欽、氮化鈥、组以及氮化纽之至少一者。另外，可以選 用適當之沉積方式，例如濺鍍法，加上第一間隙壁213的位 置，使得第一金屬層220的水平部分221與第一金屬層220 的垂直部分222盡量地均勻覆蓋在基材2〇1與第一間隙壁 213之上。 雖然第一金屬層220水平部分221的厚度與第一金屬層 220的垂直部分222的厚度可能會不同，然而較佳者，第一 金屬層220水平部分221的厚度與第一金屬層22〇的垂直部 分222的厚度比值能介於30%~70%之間。由於第一間隙壁 201116475 213的存在，第一金屬層220的水平部分221與第一金屬層 220垂直部分222的夾角，亦即位於斜角溝渠202底部之第 一金屬層220的夾角，會介於90度-135度之間。另外，亦 由於第一間隙壁213的存在，第一金屬層220的轉角223部 分也會較為圓鈍化（corner rounding)。 再來，如第8圖所示，將第二材料層230共形地覆蓋在 第一金屬層220上。第二材料層230可以為一介電材料，例 >1 . . 如氧化矽、氮化矽、氮氧化矽或碳化矽之至少一者。或者， 第二材料層230可以具有一複合結構，例如包含氧化矽、氮 化矽、氮氧化矽及/或碳化矽之複合結構，其經由分別之沉積 與蝕刻所形成。 之後，請同時參考第8圖與第9圖，進行第二次之蝕刻 步驟，例如一乾#刻步騾。第二次之#刻步驟，較佳仍然會 盡量移除第二材料層230之水平部分231，但又保留第二材 料層230部分之垂直部分232，亦即位於斜角溝渠202側壁 203上之第二材料層230。於是第二材料層230部分之垂直 部分232便成為第二間隙壁233。 接下來，如第10圖所示，又將另外之第二金屬層240 共形地覆蓋在第二間隙壁233與第一金屬層220之上，於是 形成了立體振膜電極250。第二金屬層240可以包含鋁、鈦、 氮化鈦、钽以及氮化钽之至少一者。另外，可以選用適當之 沉積方式，例如濺鍍法，加上第二間隙壁233之位置，使得 第二金屬層240的水平部分241與第二金屬層240的垂直部 201116475 '分242盡量地均勻覆蓋在第二間隙壁233與第—金屬層22〇 * 之上。雖然第一金屬層240水平部分241的厚度與第二金屬 層240的垂直部分242的厚度可能會不同，然而較佳者，第 二金屬層240水平部分241的厚度與第二金屬層24〇的垂直 部分242的厚度比值能介於3〇%〜7〇%之間。 由於第二間隙壁233的存在，第二金屬層24〇的水平部 分241與第二金屬層240垂直部分242的夾角，亦即位於斜 •角溝渠202底部之第二金屬層240的夾角，比起第一金屬層 220的水平部分221與第一金屬層22〇垂直部分222的夾 角，會更放大，例如介於90度_135度之間。而且由於第二 間隙壁233的存在，第二金屬層24〇的轉角243部分也會較 為圓鈍.化。 曰 另外，還會需要形成一背板電極260,使得背板電極26〇 鄰近立體振膜電極250。較佳者，背板電極26〇具有一多孔 •結構。視情況需要，背板電極26〇可以在立體振膜電極謂 之别或疋之後形成。如第11圖所示，如果背板電極26〇在 立體振膜電極250之前形成，可以在形成基材2〇1之溝渠2〇2 之削，先完成背板電極260。當背板電極26〇與立體振膜電 極250都 元成之時再利用背面敍刻（back-etch)方式移 除相對應區域之基材201 ’以於基底2〇1的背面形成背腔 (back-chamber)，使得立體振臈電極25〇與背板電極26〇 一 -起成為麥克風結構270之可變電容，而如第12圖所示。在 移除基材201時，還可以一併移除用來微調第一金屬層22〇 201116475 角度的第一間隙壁213。 經過前述之方法後，就可以得到一微機電系統結構。第 13圖例示本發明微機電系統結構之一實施例示意圖。本發明 微機電系統結構270可作為麥克風之用，包含一背板電極 260以及一立體振膜電極250，例如一非線形振膜電極。立 體振膜電極250鄰近背板電極260，例如位於背板電極260 上方，一起形成一可變電容。背板電極260可以具有一多孔 結構。 立體振膜電極250具有一複合結構，使得一介電層位於 兩金屬層之間。例如，立體振膜電極250包含第一金屬層 220、至少一間隙壁233與第二金屬層240。第一金屬層220 具有至少一凹槽結構202。另外，間隙壁233則位於凹槽結 構202之一側壁203上，使得第二金屬層240共形地位於第 一金屬層220與間隙壁233表面上，同時也使得間隙壁233 夾置於第一金屬層220與第二金屬層240之間。間隙壁233 可以為一介電材料。另一方面，間隙壁233也可以具有一複 合結構。例如，間隙壁233會包含氧化矽、氮化矽、氮氧化 矽、或碳化矽之至少一者。 如前所述，凹槽結構202之之底部與側璧會具有介於 90-135度間之角度。但是。第一金屬層220與第二金屬層 240位於凹槽結構202底部之角度則不相同。另外，凹槽結 構202之底部與凹槽結構之側壁之厚度可以不同，例如底部 的厚度與側壁的厚度比值能介於30%〜70%之間。第一金屬 201116475 層220與第二金屬層240可以分別獨立地包含鋁、鈦、氮化 钬、钽以及氮化组之至少一者。 在本發明微機電系統結構中，介電層可以選擇性地位於 立體振膜電極的兩金屬層之間，而形成一複合結構。此等介 電層一方面可以微調複合結構之形狀，另一方面可以緩衝麥 克風在使用時，聲波震動所產生之各種壓縮或是伸張應力， 而能夠使得具有複合結構之立體振膜電極具有更高之機械 強度。而且本發明微機電系統結構的製作步驟還無涉於金屬 層的蝕刻步驟，於是還同時具有製作流程得以更為簡化之優 以上所述僅為本發明之較佳實施例，凡依本發明申請專利範圍 所做之均等變化與修飾，皆應屬本發明之涵蓋範圍。 【圖式簡單說明】 第1圖至第3圖為習知製造微機電系統麥克風結構之方 法示意圖。 第4圖至第12圖例示製造本發明微機電系統結構之一 實施方法示意圖。 第13圖例示本發明微機電系統結構之一實施例示意圖。 【主要元件符號說明】 10微機電系統裝置 11 201116475 12基底 14基部犧牲層 16第一金屬層 18第一微型金屬網 20第一犧牲層 22第二金屬層 26第二犧牲層 28第三金屬層 32第三犧牲層 201基材 202斜角溝渠/凹槽結構 203側壁 210第一材料層 211水平部分 212垂直部分 213第一間隙壁 220第一金屬層 221水平部分 222垂直部分 223轉角 230第二材料層 231水平部分 232垂直部分 201116475 — 233第二間隙壁 .240第二金屬層 241水平部分 .242垂直部分 243轉角 250立體振膜電極 260背板電極 A 270麥克風結構/微機電系統結構Material steps, such as a dry #刻 step. In the first etching step, preferably, the horizontal portion 211 of the first material layer 210 is removed, but the vertical portion 212' of the portion of the second layer 210 is retained, that is, on the sidewall of the beveled trench 2〇2. The first material layer 210. Thus, the vertical 邛 eight 212 of the portion of the first material layer 210 becomes the first spacer 213. Continuing, as shown in Fig. 7, the first metal layer 220 is conformally overlaid on the substrate 201 and the first spacer 213. The first metal layer 220 may include at least one of Shao, Qin, tantalum nitride, group, and nitride. In addition, a suitable deposition method, such as sputtering, may be applied, and the position of the first spacer 213 is added such that the horizontal portion 221 of the first metal layer 220 and the vertical portion 222 of the first metal layer 220 are uniformly covered as much as possible. The material 2〇1 is above the first spacer 213. Although the thickness of the horizontal portion 221 of the first metal layer 220 may be different from the thickness of the vertical portion 222 of the first metal layer 220, preferably, the thickness of the horizontal portion 221 of the first metal layer 220 is different from that of the first metal layer 22 The thickness ratio of the vertical portion 222 can be between 30% and 70%. Due to the presence of the first spacers 201116475 213, the angle between the horizontal portion 221 of the first metal layer 220 and the vertical portion 222 of the first metal layer 220, that is, the angle of the first metal layer 220 at the bottom of the oblique trench 202, Between 90 degrees and 135 degrees. In addition, due to the presence of the first spacer 213, the corner 223 portion of the first metal layer 220 is also relatively rounded. Further, as shown in Fig. 8, the second material layer 230 is conformally covered on the first metal layer 220. The second material layer 230 may be a dielectric material, such as >1 . . . such as at least one of cerium oxide, cerium nitride, cerium oxynitride or cerium carbide. Alternatively, the second material layer 230 may have a composite structure such as a composite structure comprising ruthenium oxide, ruthenium hydride, ruthenium oxynitride, and/or tantalum carbide, which are formed by separate deposition and etching. After that, please refer to Figure 8 and Figure 9 at the same time for the second etching step, such as a dry step. The second engraving step preferably still removes the horizontal portion 231 of the second material layer 230, but retains the vertical portion 232 of the second material layer 230 portion, that is, on the side wall 203 of the beveled trench 202. The second material layer 230. The vertical portion 232 of the portion of the second material layer 230 then becomes the second spacer 233. Next, as shown in Fig. 10, another second metal layer 240 is conformally overlaid on the second spacer 233 and the first metal layer 220, thereby forming the stereo diaphragm electrode 250. The second metal layer 240 may include at least one of aluminum, titanium, titanium nitride, tantalum, and tantalum nitride. In addition, a suitable deposition method, such as sputtering, plus the position of the second spacer 233 may be selected such that the horizontal portion 241 of the second metal layer 240 and the vertical portion 201116475 '242 of the second metal layer 240 are as uniform as possible. Covering the second spacer 233 and the first metal layer 22〇*. Although the thickness of the horizontal portion 241 of the first metal layer 240 and the thickness of the vertical portion 242 of the second metal layer 240 may be different, preferably, the thickness of the horizontal portion 241 of the second metal layer 240 and the thickness of the second metal layer 24 The thickness ratio of the vertical portion 242 can be between 3% and 7%. Due to the presence of the second spacer 233, the angle between the horizontal portion 241 of the second metal layer 24 and the vertical portion 242 of the second metal layer 240, that is, the angle of the second metal layer 240 at the bottom of the oblique trench 202 is The angle between the horizontal portion 221 of the first metal layer 220 and the vertical portion 222 of the first metal layer 22 is more amplified, for example, between 90 degrees and 135 degrees. Moreover, due to the presence of the second spacer 233, the portion of the corner 243 of the second metal layer 24 is also relatively blunt. Further, it is also necessary to form a back plate electrode 260 such that the back plate electrode 26 is adjacent to the stereoscopic diaphragm electrode 250. Preferably, the backing plate electrode 26 has a porous structure. The backing plate electrode 26A may be formed after the orthoscopic diaphragm electrode is said to be different or desired, as the case may be. As shown in Fig. 11, if the backing plate electrode 26 is formed before the three-dimensional diaphragm electrode 250, the backing plate electrode 260 can be completed first in the trench 2〇2 where the substrate 2〇1 is formed. When the back plate electrode 26A and the stereoscopic film electrode 250 are both formed, the substrate 201' of the corresponding region is removed by a back-etching method to form a back cavity on the back surface of the substrate 2〇1 ( The back-chamber is such that the three-dimensional vibrating electrode 25A and the back plate electrode 26 become the variable capacitance of the microphone structure 270, as shown in FIG. When the substrate 201 is removed, the first spacer 213 for finely adjusting the angle of the first metal layer 22 〇 201116475 can also be removed. After the foregoing method, a MEMS structure can be obtained. Fig. 13 is a view showing an embodiment of the structure of the MEMS of the present invention. The MEMS structure 270 of the present invention can be used as a microphone, including a backing plate electrode 260 and a stereoscopic diaphragm electrode 250, such as a non-linear diaphragm electrode. The body diaphragm electrode 250 is adjacent to the backing plate electrode 260, for example, above the backing plate electrode 260, together forming a variable capacitance. The back plate electrode 260 may have a porous structure. The stereo diaphragm electrode 250 has a composite structure such that a dielectric layer is located between the two metal layers. For example, the stereo diaphragm electrode 250 includes a first metal layer 220, at least one spacer 233, and a second metal layer 240. The first metal layer 220 has at least one groove structure 202. In addition, the spacer 233 is located on one of the sidewalls 203 of the recess structure 202 such that the second metal layer 240 is conformally located on the surface of the first metal layer 220 and the spacer 233, and also causes the spacer 233 to be sandwiched first. The metal layer 220 is between the second metal layer 240. The spacer 233 may be a dielectric material. On the other hand, the spacer 233 may have a composite structure. For example, the spacer 233 may contain at least one of cerium oxide, cerium nitride, cerium oxynitride, or cerium carbide. As previously mentioned, the bottom and side turns of the groove structure 202 will have an angle of between 90 and 135 degrees. but. The angle at which the first metal layer 220 and the second metal layer 240 are located at the bottom of the groove structure 202 is different. In addition, the thickness of the bottom of the groove structure 202 and the side wall of the groove structure may be different, for example, the ratio of the thickness of the bottom portion to the thickness of the side wall may be between 30% and 70%. The first metal 201116475 layer 220 and the second metal layer 240 may independently comprise at least one of aluminum, titanium, tantalum nitride, niobium, and nitride groups, respectively. In the MEMS structure of the present invention, the dielectric layer can be selectively positioned between the two metal layers of the stereomembrane electrode to form a composite structure. On the one hand, these dielectric layers can finely adjust the shape of the composite structure, and on the other hand, can buffer various compression or tensile stress generated by the acoustic vibration of the microphone during use, and can make the stereo diaphragm electrode with the composite structure higher. Mechanical strength. Moreover, the manufacturing steps of the MEMS structure of the present invention are not involved in the etching step of the metal layer, so that the manufacturing process is further simplified. The above is only a preferred embodiment of the present invention, and the application according to the present invention is applicable. Equivalent changes and modifications made to the scope of the patent are intended to be within the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 to Fig. 3 are schematic diagrams showing a conventional method for fabricating a microphone structure of a MEMS system. 4 to 12 are views showing a method of manufacturing one of the structures of the MEMS of the present invention. Figure 13 is a view showing an embodiment of the structure of the MEMS system of the present invention. [Major component symbol description] 10 MEMS device 11 201116475 12 substrate 14 base sacrificial layer 16 first metal layer 18 first micro metal mesh 20 first sacrificial layer 22 second metal layer 26 second sacrificial layer 28 third metal layer 32 third sacrificial layer 201 substrate 202 beveled trench/groove structure 203 sidewall 210 first material layer 211 horizontal portion 212 vertical portion 213 first spacer 220 first metal layer 221 horizontal portion 222 vertical portion 223 corner 230 second Material layer 231 horizontal portion 232 vertical portion 201116475 - 233 second spacer wall 240 second metal layer 241 horizontal portion 242 vertical portion 243 corner 250 stereo diaphragm electrode 260 back plate electrode A 270 microphone structure / MEMS structure
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