201141246 六、發明說明： 【發明所屬之技術領域】 [0001] 本發明有關一種微機電電容式麥克風’尤指一種振膜 平整度高且應力殘留度低之微機電電容式麥克風。 [先前技術] [0002] 電子產品的發展趨勢一向朝體積輕薄、效率提升的方 •向前進，麥克風的演進亦不例外。麥克風用以接收聲音 • 並將其轉換為電氣訊號，在曰常生活中應用廣泛，例如 裝置於電話、手機、錄音筆等，以電容式麥克風為例， f) 聲音的變化會以音波式迫使薄膜豬構產生相對應的變 形，薄膜結構的變形會導致魔容發生:變化，爰此，可藉 感測電容變化而讀出壓差值而獲知聲音訊的變化。 [00〇3] 相較於傳統駐極電容式麥克風（electret condens er microphone, ECM) ， 微機電 (Micro-Electro-Mechanical Systems，MEMS)式麥 克風可利用積體電路的製程技術，將機械元件與電子元 Q 件整合於一半導體材料上，藉此製作出微型的麥克風， 乃漸成微型麥克風的主流。微機電式麥克風除重量輕、 體積小、省電外，尚具備的優點包括其可利用表面黏著 (surface mount)方式生產、能夠忍受較高的回焊溫度 (reflow temperature)、易於與互補式金屬氧化物半 導體（CMOS)製程以及其他音訊電子裝置整合，以及具有 較佳的抗射頻（RF)和電磁干擾（electromagnetic interference， EMI) 的特性》 [0004] 099115380 圖1」顯示一習知微機電電容式麥克風1的構造示意 表單編號A0101 第3頁/共30頁 0992027246-0 201141246 圖，其包含一背極板2(back-plate)、一可撓式可撓式 振膜3(membrane or diaphragm)以及一間隔件4。其 中’該間隔件4設置於背極板2與可撓式振膜3之間，致使 可撓式振獏3之周緣可承靠固定於該件隔件4，並與背極 板2相互絕緣隔離並平行設置，彼此分別形成一平行電容 板結構的上電極與下電極；背極板2對應可撓式振膜3處 開設有複數個音孔5(air hole)，該些音孔5貫通背極板 2，並連通開設於一矽基板6的一背腔7(1^以chamber) 〇 [0005] 分別對該背極板2輿可撓式振膜3施加電壓，可使其電 性相異並帶有電荷，形成一電容結構。根據平行電極板 的電谷公式.C=eA/d (其中ε為介電係數 (dielectric constnt)、Α為兩電極板重合面積、d為 兩電容板之間距（gap))，吾人可知兩電容板間的間距變 化將改變電容值。藉此，當一音波作用於可撓式振膜3而 造成該可撓式振膜3振動、形變時，可撓式振膜3與背極 板2之間的間距將會改變，使得竜容隨之變化而可轉換成 電氣訊號輸出。位於可撓式振膜3與背極板2之間受擾動 、壓縮的空氣，則可自該些音孔5釋放至該背腔7，避免 氣壓變動過大而損壞可撓之可撓式振膜3和背極板2結構 〇 [0006] 請配合參閱「圖2」’其顯示一微機電電容式麥克風1 的封裝示意圖。該微機電電容式麥克風丨設置於一基板8 ，並封裝於一金屬蓋體9形成的容置空間内。其中，微機 電電容式麥克風1的可撓式振膜3與背極版2分別電性連接 099115380 表單編號A0101 第4頁/共30頁 0992027246-0 201141246 [0007] Ο [0008] ❹ 至一轉換晶片10,俾使背極板2與可撓式振膜3之間的電 ，化可藉該轉換晶片i。轉換成電氣訊號而輸出。 習用之微機電電容式麥克風係透過音壓造成可挽式振 形變的特性，來獲致可撓式振膜與背極板間的電容改 變。惟，以薄膜沉積可撓式振膜的製程溫度極高，且因 掎料彼此間的熱膨脹係數互有差異，如此將使得振膜在 '的過程中累積程度不—的張應力或壓應力。殘存於 振膜的應力會導致振_曲，或是形成敏摺而導致振膜 表面不平整ϋ降低其感測卿精準度4進—步地 麥克風的靈敏度（sensitivi ty)與振膜的殘留應力呈 現反比關係，因此過高的應々殘留將等致靈敏度降低。 據此，美國專利第US549Q220號之「Solid state ondenser and microphone devices」.提出一種無 固定邊界的懸浮振膜，利用一懸臂梁来支撐振膜，使振 膜懸浮藉以釋放溫度效應造成的應力；美丨國專利第 US5870482號之「Miniature silicon condenser microphone」則延伸應用設计出大型平板振膜僅固定一 邊的結構；或如美國專利第7〇23〇66號之rSiiic〇I1 microphone」’透過振膜周緣的特殊結構設計，例如於 振膜周緣設計切線式的支撐彈簧，來改善應力殘留的問 題。惟’不管振膜利用懸臂樑支撐而懸浮，或是改良其 周緣結構方式以解決應力殘留的問題，其製程與設計均 較為複雜’且無法完全解決應力殘留的問題。 【發明内容】 爰此’本發明之目的在於解決上述熱應力殘留的問題 099115380 表單編號A0101 第5頁/共30頁 0992027246-0 [0009] 201141246 [0010] [0011] [0012] [0013] 099115380 ，進而提出一種振膜平整度高、應力釋放能力佳且製造 容易的微機電電容式麥克風。 為了達成前述目的，本發明係透過一支撐部承固振膜 的中心部分，以提供振膜足夠的空間釋放應力。本發明 提出之微機電電容式麥克風包含一基座、一背極板、一 固定件以及一振膜；其中背極板設置於基座，開設有複 數個音孔；基座開設一背腔，俾使該些音孔連通該背腔 ;固定件設置於該基座，並包含一支撐部，該支撐部並 承固振膜的中心部分，致使振膜平行且對應該背極板設 置；藉此，該振膜上的應力可自該支撐部朝外釋放。 本發明提出之微機電電容式麥克風，其振膜係以中心 部分作為支撐，可使殘留於振膜的應力有空間自内而外 釋放，並克服振膜因應力導致變形、皺摺、破裂等問題 。有關本發明的詳細技術内容及較佳實施例，配合圖式 說明如後。 【實施方式】 本發明提出一種微機電電容式麥克風，其係利用一支 撐元件支持振膜之形心，藉以輔助振膜達到釋放應力之 效。有關本發明之詳細說明及技術内容，現配合圖式說 明如下： 請參閱「圖3-1」與「圖3-2」所示，在本發明之一 實施例中，所提出之微機電電容式麥克風20包含：一基 座21、一振膜22、一固定件23以及一背極板24 ;其中， 該背極板24設置於基座21上，背極板24開設有貫通背極 板24的複數個音孔25 ;該基座21相對於背極板24的位置 表單編號A0101 第6頁/共30頁 0992027246-0 201141246 包含一背腔26 ’俾使該些音孔25得以連通該背腔26 ;該 固足件23汉置於s亥基座21而橫跨於該背腔26 ;固定件 部27 ’使得該振膜22可以振膜22的中 〜科承m於θ支標部27，以平行設置於背極板24一侧 [0014] Ο 須明的是’由於殘存振膜22上的應力通常會自振膜22 中心朝向振膜22外緣呈放射狀的方式釋放， 因此為達較 佳的應力釋放效果’該振膜22可藉由支撐部27支持於振 骐22靠近中心部分。其中，考量支部27穩定承固振膜 22的效果’支擇部27支持振膜22的中心部分可為振膜22 之形心（重心）或是位於振膜22非邊緣的對稱軸線上，舉 例來說’如承固於圓形振膜22的圓心，但不以此為限； 且為方便說明’後载均以形心部分作代表。此外，該支 撐部27可為一故設於該固定件23的一極趙。 [0015] ❹ 在上述之一實施例中，該振膜22為一可撓式振膜。因 此，振膜22的形心部分可承固於支撐部27而形成一相對 固定端，振膜2 2周緣則形成相.對之一自由端，可隨音波 作用而擺動或形變。因此，殘留於該振膜22的應力自上 述之固定端朝向自由端釋放，避免應力造成振膜22皺摺 或是不平整。 [0016] 099115380 在上述之一實施例中’該基座21例如為一碎基板’其 上開設圓形之背腔2 6 ;該固定件2 3儀呈一交叉樣態’端 緣固定於該基座21之背腔26邊緣；該背極板24固定設置 於該基座21之背腔26 —側’開設複數個音孔25並預留有 固定件23的設置空間。藉此’振膜22可平行設置於背極 表單編號A0101 第7頁/共30頁 0992027246-0 201141246 板24上方’兩者形成平行電容板結構。請再參閱「圖4」 所示’微機電電容式麥克風2〇於運作時’振膜22與背極 板24可分別輸入正負電壓，使其帶有電性相異之電荷而 為平行板電容。當振膜22之一表面承受聲音作用時，來 自聲音的壓力可使振骐22的自由端擺動而變形，而改變 振膜22與背極板24間的電容。藉此，經由外部電路的分 析與運算’吾人可將聲音訊號轉變為電氣訊號而輪出。 同時，因振膜22振動而受擾的空氣可自背極板24的音孔 25排至背腔26。 [00Π] 在上述一實施例中，該微機電電容式麥克風30可更包 含至少一絕緣件28(顯示於r圖4」），該絕緣件28設置於 振膜22與背極板24之間，例如設置於振膜22面對背極板 24側或該、背極板24面對振膜22侧，如「圖4」顯示位於背 極板24的兩絕緣件28 ’分別設置於背極板24的相異兩端 。當振膜22承受過大的聲壓而導致振膜22變形量過大時 ’該絕緣件28可提供一緩衝效果並作為振膜22與背極板 24之間的電性分隔’避免振膜22與背極板24產生電性接 觸而損壞。 [0018] 振膜22形心以支撐部27承固的設計亦可應用於一剛性 振膜。請參閱「圖5-1」與「圖5_2」所示，其為本發明 之第二實施例之立體示意、剖視圖。本實施例提出之微 機電電容式麥克風30包含一基座31、一剛性振膜32、一 彈性元件33以及一背極板34。其中，該背極板34設置於 基座31上’背極板34開設有貫通背極板34的複數個音孔 35 ;該基座31相對於背極板34的位置包含一背腔36，使 099115380 表單編號A0101 第8頁/共30頁 0992027246-0 201141246 得該些音孔35得以連通該背腔36。該剛性振膜32固定於 該彈性元件33而平行設置於背極板34—侧。因此，該背 極板34可相對於剛性振膜32形成一固定端，該剛性振膜 32則可因彈性元件33的彈性作用而位移，藉以相對該背 極板34形成一活動端。是故，當一音波作用於剛性振膜 3 2而致使剛性振膜3 2相對背極板3 4位移時，該剛性振膜 32可始終與背極板34保持平行而平行背極版34法向量方 向（即Z軸方向）位移。因此，根據前述平行電極板電容公 式，剛性振膜3 2與背極板3 4之間的電容變化便可改寫為 ® Δ(：=ε A/(d-^x)。其中，Δχ為剛性振膜32受音壓 (acoustic pressure)作用後的位移量，d為剛性振膜 32文音壓作用前與背極板34的原始間距。故，相較於習 知可撓式振膜上各點與背極板34間的間距改變量不同， 本發明之電容變化與AX有關，如此可提供更大的電容變 化量輸出，有效提升麥克風的靈敏度。 剛 請配合參閱「圖5-2」，在上述之一實施例中，該基 〇 座31例如為一矽基板，其上開設圓形之背腔36 ;該彈性 70件33係呈一十字平板交又樣態，四端固定於該基座 之背腔36邊緣；該剛性振膜32成一圓形狀，並藉—支撐 件37(anch〇r)固設於彈性元件33之十字交叉處，使剛性 振膜32平彳了彈性元件33所構成之平面；該支斜37相對 於彈性元件33之另-端固定於剛性振膜32之圓心，使支 樓件3 7承@1剛性振膜3 2時得以保持該剛性振膜3 2的物理 平衡，並輔助剛性振膜32進行熱製程時的應力釋放。 剛 該背極板34111定設置於該基細之背腔36-側，開 099115380 表單編號A0101 第9頁/共30頁 0992027246-0 201141246 設複數個音孔35並預留有彈性元件33的設置空間。藉此 ’剛性振膜32可平行設置於背極板34上方，兩者形成平 行電容板結構。請再參閱「圖6」，微機電電容式麥克風 30於運作時，剛性振膜32與背極板34可分別輸入正負電 壓’使其帶有電性相異之電荷而為平行板電容。當剛性 振膜32之一表面承受聲音作用時，來自聲音的墨力可傳 遞至彈性元件33致使其形變’俾使剛性振膜32朝向背極 板34位移（Z軸方向），而改變兩者間的電容。藉此，經由 外部電路的分析與運算，吾人可將聲音訊號轉變為電氣 訊遽而輸出。 [〇〇21] 在上述一實施例中，該徽機電電容式麥克風30可更包 含至少一絕緣件38(顯示於「圖6」），該絕緣件38設置於 剛性振膜32與背極板34之間，例如設置於翊性振膜32面 對背極板34側或該背極板34面對剛性振膜32側，如「圖6 」顯示位於背極板34的兩絕緣件38，分別設置於背極板 34的相異兩端。當剛性振膜32承受過大的聲墨而導致剛 性振膜32朝背極板34的位移量過大時，該絕緣件38可提 供—緩衝效果並作為剛性振膜32與背極板34之間的電性 分隔’避免剛性振則2與背極板34產生電性接觸而損壞 [0022] 在上述一實施例中，該剛性振膜32可包含複數個結構 加強部（圖中未示）’該些結構加強部例如為加強肋 «Reinforced rib)，可設置於剛性振膜32一 侧，用以 加強剛性振膜32整體之結構強度與並保持剛性振膜“之 099115380 表單編號A0101 第10頁/共30頁 0992027246-0 201141246 [0023] 同理，在上述之另一實施例中，該背極板34可包含複 數個結構加強部39，該些結構加強部39例如為加強肋， 可設置於該背極板34背對於剛性振膜32之一侧，用以加 強背極板34整體之結構強度與並保持背極板34的剛性。 [0024] Ο 為方便說明與瞭解，前載所述係將功能不同之結構、 元件分開定義。惟，須說明的是，上述所述及之結構或 元件可互相獨立分離而組裝，或是藉由微機電或半導體 製程，利用蝕刻、微影、回填等該領域知悉之技術直接 製作而成，例如應用MOSBE之微機電技術平台製程技術來 製造本發明提出之微機電電容式麥克風，其相關之平台 技術可參閱2005年發表之「The Molded Surfaee_ micromachining and Bulk Etching Release (MOSBE) Fabrication Platform on (111) Si for MOEMSj (Journal of Micromechanics and Mi- croengineering，v〇l. 15，260-265)，在此不 加贅述。 〇 [0025] 請再參閱「圖7-1」至「圖7-9」之製造上述微機電 電容式麥克風20—實施例的流程示意圖，該些圖式顯示 沿「圖5-1」中線段K-K’的截面示意，且在不影響本發 明的實施與了解下，省略掉於不同元件中的電性佈線流 程。首先，備製一用於製做基座31的基材，例如為一石夕 基板40，如「圖7-1」所示；接著於該矽基板40定義背極 板34之設置位置，並於其上#刻出用於形成前述結構加 強部39的溝槽41，如「圖7-2」；接續地’於該梦基板 40上沉積一層多晶石夕（p〇ly-si 1 icon)層42，該多晶矽 099115380 表單編號A0101 第11頁/共30頁 0992027246-0 201141246 層42並回填該㈣槽4卜以形成背極板34之結構加強部 39、°構，如「圖7 —3」。緊接著’於該多晶石夕層42的預設 位置餘刻出彈性元件33與音孔35位置並同時定義出背 極板34之尺寸範圍，如「圖卜4」；該背極板附藉該些 、·Ό構加強。卩3 9保持其表面平整與結構剛性，該彈性元件 33則可藉多晶梦層的厚度改變或材料選擇，調整自身之 彈性。 然後，於背極板34上形成前述之絕緣件38，該些絕緣 件38之材質例如為氮化矽（silicon nitride，如 Si/p，如「圖7_5j所示；接著，於背極板以上方形成 一中間層43並同時定義出支撐件37的形成位置，該支撐 件37的形成位置位於彈性元件33上方，如「圖卜6」，該 中間層43例如為二氧化矽（Si〇2);而後，於該中間層43 上再沉積一多晶矽層44，該多晶矽層44用以定義出剛性 振膜32與支撐件37,如「圖7 — 7」；接續地，自矽基板 40底側蝕刻出背腔36，如「圖7_8」；最後，蝕刻去除該 中間層43，致使剛性振膜32舞該支撐件37設置於彈性元 件33上，並平行於背極板34，如「圖7_9」。 圖8」顯示將上述實施例的頻率反應測試結果，係 將前述之微機電電容式麥克風3〇電性連接一電容讀出晶 片（capacitance readout IC)(MS311〇)，並置於一 半音波暗室（semi-anechoic chamber)收取揚聲機 (loudspeaker)的訊號結果。由圖可知，在聲準位 (sound-level)為94dB下，上述微機電電容式麥克風3〇 實施例的頻率感測範圍介於1 〇 ~ 2 0，0 〇 〇Hz之間。靈敏产 0992027246-0 099115380 表單編號A0101 第12頁/共30頁 2U1141246 [0028] Ο [0029] ο [0030] (sensitivity)約為 126 微機電製程製造出的微機電二：:或責議/Pa… 高外，更兼具體積小、 奋式麥克風30，除靈敏度 式振膜難以處理應力^本等優點。相較於習知可撓 應力，可獲致較佳的麵靈丨性振麟不易殘留 須再特別說明定義的是 枒料之廍声类—μ 上述剛性振膜32並非純然以 办 & ^ ’而雜配微機電電容式麥克風的電 各感測原理而加以定義。熹故 所謂之剛性振膜32係指 振膜不藉自身的形變來改變與背極板34間的電容值，而 乃須搭配-彈性元伽，並藉彈性元賴的彈性或形變 來改變與背極板34間的電容值，故所述之彈性元件33也 不以上述實施例所顯示者為限。 综上所述，本發明提出之微機電電容式麥克風，其振 膜係以形心作為支撐，藉以使殘留於振膜的應力有空間 自内而外釋放，以克服振膜因高溫製程產生殘留應力， 導致振膜變形或破裂筝問題》 惟以上所述者，僅為本發明之較佳實施例，非欲偏限 本發明專利之專利保護範圍，故舉凡運用本發明說明書 及圖式内容所為之等效變化與修飾，均同理包含於本發 明之權利保護範圍，合予陳明。 以 【圖式簡單說明】 [0031] 本發明的實施方式係結合圖式予以描述： [003¾ 「圖1」為習知微機電電容式之一麥克風晶片的構造示意 圖； 099115380 表單編號A0101 第13頁/共30頁 0992027246-0 201141246 [0033] 「圖2」為習知微機電電容式麥克風的封裝示意圖； [0034] 「圖3-1」為本發明之微機電電容式麥克風一實施例之立 體示意圖； [0035] 「圖3-2」為本發明之微機電電容式麥克風一實施例之立 體剖視圖； [0036] 「圖4」為本發明之微機電電容式麥克風一實施例之作動 示意圖； [0037] 「圖5-1」為本發明之微機電電容式麥克風另一實施例之 立體不意圖， [0038] 「圖5-2」為本發明之微機電電容式麥克風另一實施例之 立體剖視圖； [0039] 「圖6」為本發明之微機電電容式麥克風另一實施例之作 動示意圖； [0040] 「圖7-1」至「圖7-9」為本發明之微機電電容式麥克風 另一實施例之流程示意圖；及 [0041] 「圖8」為上述實施例於不同頻率下的輸出結果圖。 【主要元件符號說明】 [0042] 先前技術： [0043] 1.......微機電電容式麥克風 [0044] 2.......背極板 [0045] 3.......振膜 [0046] 4.......間隔件 099115380 表單編號 A0101 第 14 頁/共 30 頁 0992027246-0 201141246 [0047] 5...... •音孔 [0048] 6 · · . · · · •矽基板 [0049] 7...... •背腔 [0050] 8...... •基板 [0051] 9...... •金屬蓋體 [0052] 10...... •轉換晶片 [0053] 本發明： Ο [0054] 20, 30 · · · · •微機電電容式麥克風 [0055] 21,31 ·... •基座 [0056] 22 · · · · · · •振膜 [0057] 23...... •固定件 [0058] 24, 34 . . . .背極板 [0059] 25, 35 · · · · •音孔 [0060] 26,36···· •背腔 [0061] 27 · · · · · · •支撐部 [0062] 28, 38 .... •絕緣件 [0063] 32...... •剛性振膜 [0064] 33...... •彈性元件 [0065] 37...... •支撐件 099115380 表單編號A0101 第15頁/共30頁 0992027246-0 201141246 [0066] 39.......結構加強部 [0067] 40.......矽基板 [0068] 41.......溝槽 [0069] 42.......多晶石夕層 [0070] 43...... ·中間層 [0071] 44.......多晶矽層 099115380 表單編號 A0101 第 16 頁/共 30 頁 0992027246-0201141246 VI. Description of the Invention: [Technical Field] [0001] The present invention relates to a microelectromechanical condenser microphone, particularly a microelectromechanical condenser microphone having high diaphragm flatness and low stress residual. [Prior Art] [0002] The development trend of electronic products has always been toward thinner and lighter, and the efficiency is improving. The evolution of microphones is no exception. Microphones are used to receive sounds and convert them into electrical signals, which are widely used in everyday life, such as telephones, cell phones, voice recorders, etc., using condenser microphones as an example. f) Sound changes are forced by sound waves. The film pig structure produces corresponding deformation, and the deformation of the film structure causes the magic volume to occur: change, and the change of the pressure difference can be read by sensing the change of the capacitance to obtain the change of the sound signal. [00〇3] Compared to traditional electret condenser microphones (EMMs), Micro-Electro-Mechanical Systems (MEMS) microphones can utilize mechanical process technology to integrate mechanical components with The electronic component Q is integrated into a semiconductor material to create a miniature microphone, which is gradually becoming the mainstream of the miniature microphone. In addition to light weight, small size, and power saving, MEMS microphones have advantages such as surface mount, high reflow temperature, and easy and complementary metal. Integration of oxide semiconductor (CMOS) processes and other audio electronics, as well as better resistance to radio frequency (RF) and electromagnetic interference (EMI) [0004] 099115380 Figure 1 shows a conventional microelectromechanical capacitor The configuration of the microphone 1 is shown in Form No. A0101, Page 3 of 30, 0992027246-0, 201141246, which includes a back-plate, a membrane or diaphragm. And a spacer 4. Wherein the spacer 4 is disposed between the back plate 2 and the flexible diaphragm 3, so that the periphery of the flexible vibrating ring 3 can be fixed to the spacer 4 and insulated from the back plate 2 The upper electrode and the lower electrode of the parallel capacitor plate structure are formed separately from each other, and the plurality of sound holes 5 are formed corresponding to the flexible diaphragm 3 at the back plate 2, and the sound holes 5 are penetrated. The back plate 2 is connected to a back cavity 7 of a substrate 6 (1), and a voltage is applied to the flexible film 3 of the back plate 2 to electrically Different and charged, forming a capacitor structure. According to the electric valley formula of the parallel electrode plate. C=eA/d (where ε is the dielectric constnt, Α is the overlap area of the two electrode plates, and d is the gap between the two capacitor plates), we know that the two capacitors The change in spacing between the boards will change the capacitance value. Therefore, when an acoustic wave acts on the flexible diaphragm 3 to cause the flexible diaphragm 3 to vibrate and deform, the distance between the flexible diaphragm 3 and the back plate 2 will change, so that the tolerance is changed. It can be converted into an electrical signal output. The disturbed and compressed air between the flexible diaphragm 3 and the back plate 2 can be released from the sound holes 5 to the back cavity 7 to prevent the air pressure from being excessively changed and damaging the flexible flexible diaphragm. 3 and the structure of the back plate 2 [0006] Please refer to "Figure 2" for the package diagram of a microelectromechanical condenser microphone 1. The MEMS condenser microphone is disposed on a substrate 8 and encapsulated in an accommodating space formed by a metal cover 9. The flexible diaphragm 3 of the microelectromechanical condenser microphone 1 is electrically connected to the back plate 2 respectively. 099115380 Form No. A0101 Page 4 / Total 30 Page 0992027246-0 201141246 [0007] Ο [0008] ❹ To one conversion The wafer 10 is electrically coupled between the backing plate 2 and the flexible diaphragm 3 to convert the wafer i. Converted to electrical signal and output. The conventional micro-electromechanical condenser microphone is characterized by a changeable capacitance caused by sound pressure to obtain a change in capacitance between the flexible diaphragm and the back plate. However, the process temperature for depositing a flexible diaphragm by a film is extremely high, and the thermal expansion coefficients of the tantalum are different from each other, so that the diaphragm will not accumulate in the course of the process, or the tensile stress or compressive stress. The stress remaining in the diaphragm will cause the vibration of the diaphragm, or the formation of the sensitization, resulting in uneven surface of the diaphragm, reducing the sensitivity of the sensor, the sensitivity of the microphone, and the residual stress of the diaphragm. It exhibits an inverse relationship, so excessively high residuals will reduce sensitivity. Accordingly, U.S. Patent No. US549Q220 "Solid state ondenser and microphone devices" proposes a suspended diaphragm without a fixed boundary, which uses a cantilever beam to support the diaphragm, so that the diaphragm is suspended to release the stress caused by the temperature effect; The "Miniature silicon condenser microphone" of the Japanese Patent No. 5870482 extends the application to design a structure in which a large flat diaphragm is fixed only on one side; or, as in the U.S. Patent No. 7〇23〇66, rSiiic〇I1 microphone" The special structural design of the circumference, such as the design of a tangential support spring on the periphery of the diaphragm, to improve the problem of residual stress. However, regardless of whether the diaphragm is suspended by the cantilever beam support or the peripheral structure is modified to solve the problem of residual stress, the process and design are complicated, and the problem of residual stress cannot be completely solved. SUMMARY OF THE INVENTION The object of the present invention is to solve the above problem of thermal stress residual 099115380 Form No. A0101 Page 5 / Total 30 Page 0992027246-0 [0009] 201141246 [0010] [0012] [0013] 099115380 Furthermore, a microelectromechanical condenser microphone with high flatness of the diaphragm, good stress release capability and easy manufacture is proposed. In order to achieve the foregoing object, the present invention supports the central portion of the diaphragm through a support portion to provide a sufficient space for the diaphragm to release stress. The MEMS microphone of the present invention comprises a base, a back plate, a fixing member and a diaphragm; wherein the back plate is disposed on the base, and a plurality of sound holes are opened; the base defines a back cavity. Having the sound holes communicate with the back cavity; the fixing member is disposed on the base and includes a support portion that supports the central portion of the diaphragm, so that the diaphragm is parallel and corresponds to the back plate; Thus, the stress on the diaphragm can be released outward from the support. The microelectromechanical condenser microphone proposed by the invention has the diaphragm supported by the central portion, so that the stress remaining on the diaphragm can be released from the inside and the outside, and overcomes deformation, wrinkles, cracks, etc. of the diaphragm due to stress. problem. The detailed technical content and preferred embodiments of the present invention are described in conjunction with the drawings. [Embodiment] The present invention proposes a microelectromechanical condenser microphone which supports the centroid of the diaphragm by means of a support member, thereby assisting the diaphragm to achieve the effect of releasing stress. The detailed description and technical contents of the present invention will be described below with reference to the drawings: Please refer to "FIG. 3-1" and "FIG. 3-2", in one embodiment of the present invention, the proposed microelectromechanical capacitor The microphone 20 includes a base 21, a diaphragm 22, a fixing member 23 and a back plate 24; wherein the back plate 24 is disposed on the base 21, and the back plate 24 is opened through the back plate a plurality of sound holes 25 of 24; the position of the base 21 relative to the back plate 24, form number A0101, page 6 of 30 pages 0992027246-0 201141246, including a back cavity 26', such that the sound holes 25 are connected The back cavity 26; the fixing member 23 is placed on the sill base 21 and spans the back cavity 26; the fixing portion 27' is such that the diaphragm 22 can be in the middle of the diaphragm 22 The portion 27 is disposed in parallel on the side of the back plate 24 [0014]. It is to be noted that the stress on the remaining diaphragm 22 is normally released radially from the center of the diaphragm 22 toward the outer edge of the diaphragm 22. Therefore, in order to achieve a better stress releasing effect, the diaphragm 22 can be supported by the support portion 27 near the center portion of the vibrating portion 22. The effect of the support portion 27 for stably supporting the diaphragm 22 is determined. The central portion of the diaphragm 22 supporting the diaphragm 22 may be the centroid (center of gravity) of the diaphragm 22 or the axis of symmetry of the non-edge of the diaphragm 22, for example. For example, it is fixed to the center of the circular diaphragm 22, but is not limited thereto; and for convenience of explanation, the rear load is represented by the centroid portion. In addition, the support portion 27 can be a pole formed on the fixing member 23. [0015] In one of the above embodiments, the diaphragm 22 is a flexible diaphragm. Therefore, the centripetal portion of the diaphragm 22 can be fixed to the support portion 27 to form a relatively fixed end, and the peripheral edge of the diaphragm 22 forms a pair of free ends which can be swung or deformed with the action of sound waves. Therefore, the stress remaining on the diaphragm 22 is released toward the free end from the fixed end as described above, and the stress is prevented from wrinkling or unevenness of the diaphragm 22. [0016] 099115380 In one of the above embodiments, the base 21 is, for example, a broken substrate, and has a circular back cavity 26; the fixing member 23 has a cross-shaped end edge fixed to the The back surface of the base 21 is fixed to the side of the back cavity 26 of the base 21 to open a plurality of sound holes 25 and to reserve the installation space of the fixing member 23. Thereby, the diaphragm 22 can be arranged in parallel on the back pole. Form No. A0101 Page 7 / Total 30 pages 0992027246-0 201141246 Above the board 24 Both form a parallel capacitive plate structure. Please refer to the "Micro-electromechanical condenser microphone 2" during operation. The diaphragm 22 and the back plate 24 can input positive and negative voltages respectively, so that they have electrically different charges and are parallel plate capacitors. . When one surface of the diaphragm 22 is subjected to sound, the pressure from the sound can oscillate and deform the free end of the ring 22, and the capacitance between the diaphragm 22 and the back plate 24 is changed. Thereby, the analysis and operation "via the external circuit" can turn the sound signal into an electrical signal and turn it out. At the same time, air disturbed by the vibration of the diaphragm 22 can be discharged from the sound hole 25 of the back plate 24 to the back chamber 26. In the above embodiment, the MEMS condenser microphone 30 further includes at least one insulating member 28 (shown in FIG. 4), and the insulating member 28 is disposed between the diaphragm 22 and the back plate 24. For example, the diaphragm 22 faces the back plate 24 side or the back plate 24 faces the diaphragm 22 side. As shown in FIG. 4, the two insulating members 28' located on the back plate 24 are respectively disposed on the back pole. The opposite ends of the plate 24. When the diaphragm 22 is subjected to excessive sound pressure and the deformation of the diaphragm 22 is excessively large, the insulating member 28 can provide a buffering effect and serve as an electrical separation between the diaphragm 22 and the backing plate 24 to avoid the diaphragm 22 and The back plate 24 is electrically damaged and damaged. [0018] The design in which the centroid of the diaphragm 22 is supported by the support portion 27 can also be applied to a rigid diaphragm. Referring to Figures 5-1 and Figure 5-2, there is shown a perspective view and a cross-sectional view of a second embodiment of the present invention. The MEMS condenser microphone 30 of the present embodiment comprises a base 31, a rigid diaphragm 32, an elastic member 33 and a back plate 34. The back plate 34 is disposed on the base 31. The back plate 34 defines a plurality of sound holes 35 extending through the back plate 34. The base 31 includes a back cavity 36 at a position relative to the back plate 34. Let the 099115380 form number A0101 page 8/total 30 page 0992027246-0 201141246 the sound holes 35 are connected to the back cavity 36. The rigid diaphragm 32 is fixed to the elastic member 33 and disposed in parallel on the side of the back plate 34. Therefore, the back plate 34 can form a fixed end with respect to the rigid diaphragm 32, and the rigid diaphragm 32 can be displaced by the elastic action of the elastic member 33, thereby forming a movable end with respect to the back plate 34. Therefore, when an acoustic wave acts on the rigid diaphragm 3 2 to cause the rigid diaphragm 32 to be displaced relative to the back plate 34, the rigid diaphragm 32 can always be parallel with the back plate 34 and parallel to the back plate 34 method. The vector direction (ie, the Z-axis direction) is displaced. Therefore, according to the aforementioned parallel electrode plate capacitance formula, the change in capacitance between the rigid diaphragm 32 and the back plate 34 can be rewritten as ® Δ(:=ε A/(d-^x), where Δχ is rigid The displacement of the diaphragm 32 after the acoustic pressure is applied, and d is the original spacing of the back surface of the rigid diaphragm 32 before the sound pressure is applied. Therefore, compared with the conventional flexible diaphragm The difference in the distance between the point and the back plate 34 is different, and the capacitance change of the present invention is related to AX, so that a larger capacitance change output can be provided, thereby effectively improving the sensitivity of the microphone. Just refer to "Fig. 5-2". In one embodiment, the base 31 is, for example, a base plate having a circular back cavity 36; the elastic 70 member 33 is in the form of a cross plate, and the four ends are fixed to the base. The rigid diaphragm 32 is formed in a circular shape, and is fixed at the intersection of the elastic members 33 by a support member 37 (anch〇r), so that the rigid diaphragm 32 is flattened by the elastic member 33. a plane formed; the yoke 37 is fixed to the center of the rigid diaphragm 32 with respect to the other end of the elastic member 33, so that When the floor member 3 receives the @1 rigid diaphragm 3 2, the physical balance of the rigid diaphragm 32 is maintained, and the rigid diaphragm 32 is assisted in stress release during the thermal process. The back plate 34111 is just placed on the base. Thin back cavity 36-side, open 099115380 Form No. A0101 Page 9 / Total 30 pages 0992027246-0 201141246 Set a plurality of sound holes 35 and reserve the space for the elastic elements 33. By this, the rigid diaphragm 32 can be parallel It is disposed above the back plate 34, and the two form a parallel capacitor plate structure. Please refer to FIG. 6 again. When the MEMS condenser microphone 30 is in operation, the rigid diaphragm 32 and the back plate 34 can input positive and negative voltages respectively. It has an electrically different electric charge and is a parallel plate capacitor. When one surface of the rigid diaphragm 32 is subjected to a sound action, the ink force from the sound can be transmitted to the elastic member 33 to cause it to deform, so that the rigid diaphragm 32 is oriented. The back plate 34 is displaced (Z-axis direction), and the capacitance between the two is changed. Thereby, through the analysis and calculation of the external circuit, the voice signal can be converted into an electrical signal and output. [〇〇21] In an embodiment, the emblem electromechanical The microphone 30 can further include at least one insulating member 38 (shown in FIG. 6) disposed between the rigid diaphragm 32 and the back plate 34, for example, disposed on the back surface of the diaphragm 32. The side of the plate 34 or the back plate 34 faces the side of the rigid diaphragm 32. As shown in Fig. 6, the two insulating members 38 on the back plate 34 are respectively disposed at the opposite ends of the back plate 34. When the film 32 is subjected to excessive acoustic ink and the displacement of the rigid diaphragm 32 toward the back plate 34 is excessively large, the insulating member 38 can provide a buffering effect and serve as an electrical separation between the rigid diaphragm 32 and the back plate 34. 'Attenuation of the rigid vibration 2 to make electrical contact with the back plate 34 and damage [0022] In the above embodiment, the rigid diaphragm 32 may include a plurality of structural reinforcements (not shown) For example, the reinforcing rib «Reinforced rib" may be disposed on the side of the rigid diaphragm 32 to reinforce the structural strength of the rigid diaphragm 32 as a whole and to maintain the rigid diaphragm "099115380 Form No. A0101 Page 10 of 30 0992027246-0 201141246 [0023] Similarly, in another embodiment described above, the back pole The plate 34 may include a plurality of structural reinforcing portions 39, such as reinforcing ribs, which may be disposed on one side of the back plate 34 facing away from the rigid diaphragm 32 for reinforcing the structure of the back plate 34 as a whole. The strength is and maintains the rigidity of the back plate 34. [0024] For convenience of explanation and understanding, the pre-loading system defines the structures and components with different functions separately. However, it should be noted that the structures or components described above may be independently separated and assembled, or may be directly fabricated by techniques known in the art, such as etching, lithography, backfilling, by microelectromechanical or semiconductor processes. For example, the MEMS-based microelectromechanical technology platform process technology is used to manufacture the MEMS condenser microphone proposed by the present invention. The related platform technology can be referred to the "The Molded Surfaee_micromachining and Bulk Etching Release (MOSBE) Fabrication Platform on (111) published in 2005. Si for MOEMSj (Journal of Micromechanics and Mi- croengineering, v〇l. 15, 260-265), which is not described here. 〇[0025] Please refer to "Figure 7-1" to "Figure 7-9" A schematic diagram of the process of manufacturing the above-described microelectromechanical condenser microphone 20, which shows a section along the line K-K' in "Fig. 5-1", and without affecting the implementation and understanding of the present invention, The electrical wiring process that is omitted from the different components is omitted. First, a substrate for making the susceptor 31 is prepared, for example, a slab substrate 40, as shown in FIG. 7-1; and then the ruthenium substrate 40 defines the position of the back plate 34, and The groove 41 for forming the structural reinforcement portion 39 is as shown in FIG. 7-2, and a polycrystalline stone (p〇ly-si 1 icon) is deposited on the dream substrate 40. Layer 42, the polysilicon 99 099115380 Form No. A0101 Page 11 / Total 30 Page 0992027246-0 201141246 Layer 42 and backfill the (four) slot 4 to form the structural reinforcement 39 of the back plate 34, such as "Figure 3-4 "." Immediately following the position of the polycrystalline stone layer 42, the position of the elastic member 33 and the sound hole 35 is left and the size range of the back plate 34 is defined, such as "Fig. 4"; the back plate is attached Leverage these and strengthen the structure.卩3 9 maintains its surface flatness and structural rigidity, and the elastic member 33 can adjust its elasticity by the thickness change or material selection of the polycrystalline dream layer. Then, the foregoing insulating member 38 is formed on the back plate 34, and the material of the insulating members 38 is, for example, silicon nitride (such as Si/p, as shown in FIG. 7_5j; then, above the back plate) The square forming an intermediate layer 43 and simultaneously defining the formation position of the support member 37 is formed above the elastic member 33, such as "Fig. 6", which is, for example, cerium oxide (Si〇2). And then depositing a polysilicon layer 44 on the intermediate layer 43 for defining the rigid diaphragm 32 and the support member 37, such as "Fig. 7-7"; successively, the bottom of the substrate 40 is self-twisted The back cavity 36 is etched sideways, as shown in FIG. 7-8. Finally, the intermediate layer 43 is etched away, so that the rigid diaphragm 32 dances the support member 37 on the elastic member 33 and parallel to the back plate 34, such as 7_9". Fig. 8" shows the result of the frequency reaction test of the above embodiment, which electrically connects the aforementioned microelectromechanical condenser microphone 3〇 to a capacitance readout IC (MS311〇) and places it in a half sound wave. The semi-anechoic chamber collects the speaker (loudspe) The signal result of aker). As can be seen from the figure, the frequency sensing range of the above-mentioned microelectromechanical condenser microphone 3〇 embodiment is between 1 〇~ 2 0,0 〇〇Hz at a sound-level of 94 dB. Sensitive Product 0992027246-0 099115380 Form No. A0101 Page 12 of 30 2U1141246 [0028] Ο [0030] ο [0030] (sensitivity) about 126 MEMS manufacturing MEMS 2:: or responsibility Discussion/Pa... High-level, more specific and small, exciting microphone 30, in addition to the sensitivity of the diaphragm is difficult to deal with the stress ^ and other advantages. Compared to the conventional flexible stress, can achieve better facial stimulation It is not easy to remnant. It is necessary to specify the definition of the squeaking sound of the sputum-μ. The above rigid diaphragm 32 is not purely defined by the electrical sensing principle of the MEMS micro-electromechanical condenser microphone. Therefore, the so-called rigid diaphragm 32 means that the diaphragm does not change its capacitance value with the back plate 34 by its own deformation, but it must be matched with the elastic element gamma, and the elastic element or the deformation of the elastic element is used to change and back. The capacitance value between the plates 34, so the elastic member 33 is not in the above In summary, the microelectromechanical condenser microphone of the present invention has a diaphragm supported by a centroid, so that the stress remaining in the diaphragm is spatially released from the inside to the outside, Overcoming the problem that the diaphragm is subjected to residual stress due to the high-temperature process, causing deformation or cracking of the diaphragm. However, the above description is only a preferred embodiment of the present invention, and it is not intended to limit the scope of patent protection of the present invention. The equivalent changes and modifications of the present specification and the contents of the drawings are included in the scope of the present invention and are combined with Chen Ming. BRIEF DESCRIPTION OF THE DRAWINGS [0031] Embodiments of the present invention are described in conjunction with the drawings: [0033⁄4 "FIG. 1" is a schematic diagram of a conventional microelectromechanical capacitive microphone chip; 099115380 Form No. A0101 Page 13 / Total 30 pages 0992027246-0 201141246 [0033] "Fig. 2" is a package schematic diagram of a conventional microelectromechanical condenser microphone; [0034] "Fig. 3-1" is a three-dimensional embodiment of the microelectromechanical condenser microphone of the present invention 3 is a perspective cross-sectional view of an embodiment of a microelectromechanical condenser microphone according to the present invention; [0036] FIG. 4 is a schematic diagram of an embodiment of a microelectromechanical condenser microphone according to the present invention; [0037] FIG. 5 is a perspective view of another embodiment of a microelectromechanical condenser microphone according to the present invention, and FIG. 5-2 is another embodiment of the microelectromechanical condenser microphone of the present invention. FIG. 6 is a schematic view showing another embodiment of a microelectromechanical condenser microphone according to the present invention; [0040] FIG. 7-1 to FIG. 7-9 are microelectromechanical capacitors of the present invention. Another embodiment of a microphone A schematic process; and [0041] "FIG. 8" is a result of the above-described embodiments in FIG output at different frequencies. [Main Component Symbol Description] [0042] Prior Art: [0043] 1.......Microelectromechanical condenser microphone [0044] 2.......Back plate [0045] 3.... ...diaphragm [0046] 4.......spacer 099115380 Form No. A0101 Page 14 of 30 0992027246-0 201141246 [0047] 5... • Sound Hole [0048] 6 · · · · · · 矽 substrate [0049] 7... • Back cavity [0050] 8... • Substrate [0051] 9... • Metal cover [0052] 10... • Conversion wafer [0053] The present invention: Ο [0054] 20, 30 · · · · • Microelectromechanical condenser microphone [0055] 21, 31 ·... • Base [0056] 22 · · · · · · • Diaphragm [0057] 23... • Fixing parts [0058] 24, 34 . . . . Back plate [0059] 25, 35 · · · · • Sound hole [ 0060] 26,36···· • Back cavity [0061] 27 · · · · · · Support [0062] 28, 38 .... • Insulation [0063] 32... • Rigid Diaphragm [0064] 33... • Elastic element [0065] 37... • Support 099115380 Form No. A0101 Page 15/Total 30 Page 0992027246-0 201141246 [0066] 39... ....structure Strong part [0067] 40.......矽 substrate [0068] 41....... trench [0069] 42....... polycrystalline layer [0070] 43.. .... ·Intermediate layer [0071] 44.......Polysilicon layer 099115380 Form No. A0101 Page 16 of 30 0992027246-0