TW202209515A

TW202209515A - Micro-electromechanical system device and method of forming the same

Info

Publication number: TW202209515A
Application number: TW109128837A
Authority: TW
Inventors: 夏佳杰
Original assignee: 世界先進積體電路股份有限公司
Priority date: 2020-08-24
Filing date: 2020-08-24
Publication date: 2022-03-01
Also published as: TWI775133B

Abstract

The present disclosure related to a micro-electromechanical system (MEMS) device and a method of forming the same. The MEMS device includes a substrate, a cavity, an interconnection structure and a proof mass. The substrate includes a first surface and a second surface opposite to the first surface. The cavity is disposed in the substrate to extend between the first surface and the second surface. The interconnection structure is disposed on the first surface of the substrate, over the cavity. The proof mass is disposed on the interconnection structure, wherein the proof mass is partially suspended over the interconnection structure.

Description

微機電裝置及其形成方法Microelectromechanical device and method of forming the same

本發明是關於一種微機電裝置及其形成方法，且特別是關於一種應用於聲學的微機電裝置及其形成方法。The present invention relates to a microelectromechanical device and a method of forming the same, and more particularly, to a microelectromechanical device for acoustic applications and a method of forming the same.

微機電（micro-electromechanical system, MEMS）裝置乃是利用習知半導體製程來製造的微小機械元件，透過半導體技術例如沉積、或選擇性蝕刻材料層等方式完成具有微米尺寸的機械元件。微機電裝置可利用電磁（electromagnetic）、電致伸縮（electrostrictive）、熱電（thermoelectric）、壓電（piezoelectric）或壓阻（piezoresistive）等效應進行操作，而兼具電子及機械的雙重功能，因此，常見於應用微電子領域，如加速器（accelerometer）、陀螺儀（gyroscope）、反射鏡（mirror）或聲學感測器（acoustic sensor）等。A micro-electromechanical system (MEMS) device is a micro-mechanical element manufactured by using conventional semiconductor processes. The mechanical element having a micron size is completed by means of semiconductor techniques such as deposition or selective etching of material layers. Microelectromechanical devices can operate using electromagnetic, electrostrictive, thermoelectric, piezoelectric or piezoresistive effects, and have both electronic and mechanical functions. Therefore, Commonly used in the field of applied microelectronics, such as accelerator (accelerometer), gyroscope (gyroscope), mirror (mirror) or acoustic sensor (acoustic sensor) and so on.

近年來，由於無線藍芽（true wireless stereo, TWS）耳機的快速發展，可將微機電系統加速器產品用於感測聲音的振動，為聲學換能器帶來新的視野。將微機電系統速器產品設置於該無線藍芽耳機內，可讓該無線藍芽耳機即使處於雜訊高或雜訊較多的周圍環境下依然能有力地擷取聲音。然而，因微機電系統加速器產品目前較普遍應用於手機領域，因此，其結構設計上多偏向厚而大，以致並不能滿足無線藍芽耳機微型化的設計需求。如此，目前仍然需要一種新設計的加速器以應用於聲學領域。In recent years, due to the rapid development of true wireless stereo (TWS) headsets, MEMS accelerator products can be used to sense the vibration of sound, bringing new horizons to acoustic transducers. The micro-electromechanical system accelerator product is arranged in the wireless bluetooth earphone, so that the wireless bluetooth earphone can still capture sound powerfully even in the surrounding environment with high noise or more noise. However, since MEMS accelerator products are more commonly used in the field of mobile phones, their structural design tends to be thick and large, so that they cannot meet the design requirements for miniaturization of wireless Bluetooth earphones. As such, there is still a need for a newly designed accelerator for the acoustic field.

本發明提供一種微機電裝置及其形成方法，該微機電裝置所設置的檢測質量塊（proof mass）係部分懸掛地設置在互連結構（interconnection structure）上方，藉此，該質量塊的設置位置將不會對該互連結構的剛性（stiffness）造成影響。如此，本發明之質量塊的大小、質量以及厚度可以充分擴大，以利於提高該微機電裝置的感測靈敏度。The present invention provides a microelectromechanical device and a method for forming the same. A proof mass provided in the microelectromechanical device is partially suspended above an interconnection structure, whereby the setting position of the proof mass is determined. There will be no impact on the stiffness of the interconnect structure. In this way, the size, mass and thickness of the mass block of the present invention can be sufficiently enlarged, so as to improve the sensing sensitivity of the MEMS device.

為達上述目的，本發明的一實施例係提供一種微機電裝置，包含基底、溝槽、互連結構以及質量塊。該基底，具有一第一表面以及相對於該第一表面的一第二表面。該溝槽設置在該基底內，並延伸於該第一表面以及該第二表面之間。該互連結構設置在該基底的該第一表面上，並且位在該溝槽的上方。質量塊設置在該互連結構上，其中，該質量塊係部分懸掛於該互連結構的上方。To achieve the above object, an embodiment of the present invention provides a microelectromechanical device including a substrate, a trench, an interconnection structure, and a proof mass. The substrate has a first surface and a second surface opposite to the first surface. The groove is disposed in the substrate and extends between the first surface and the second surface. The interconnect structure is disposed on the first surface of the substrate over the trench. A mass is disposed on the interconnecting structure, wherein the mass is partially suspended above the interconnecting structure.

為達上述目的，本發明的另一實施例係提供一種微機電裝置的形成方法，包含以下步驟。首先，提供一基底，該基底具有一第一表面以及相對於該第一表面的一第二表面。接著，於該基底內形成一溝槽，該溝槽延伸於該第一表面以及該第二表面之間。然後，於該基底的該第一表面上形成一互連結構，該互連結構位在該溝槽的上方。之後，於該互連結構上形成一質量塊，其中，該質量塊係部分懸掛於該互連結構的上方。To achieve the above object, another embodiment of the present invention provides a method for forming a microelectromechanical device, which includes the following steps. First, a substrate is provided, the substrate has a first surface and a second surface opposite to the first surface. Next, a trench is formed in the substrate, and the trench extends between the first surface and the second surface. Then, an interconnect structure is formed on the first surface of the substrate, and the interconnect structure is located above the trench. Afterwards, a mass is formed on the interconnecting structure, wherein the mass is partially suspended above the interconnecting structure.

為使熟習本發明所屬技術領域之一般技藝者能更進一步了解本發明，下文特列舉本發明之數個較佳實施例，並配合所附圖式，詳細說明本發明的構成內容及所欲達成之功效。並且，熟習本發明所屬技術領域之一般技藝者亦能在不脫離本發明的精神下，參考以下所舉實施例，而將數個不同實施例中的特徵進行替換、重組、混合以完成其他實施例。In order to enable those skilled in the art to which the present invention pertains to further understand the present invention, a number of preferred embodiments of the present invention are listed below, together with the accompanying drawings, to describe in detail the composition of the present invention and what it wants to achieve effect. Moreover, those of ordinary skill in the technical field to which the present invention pertains can also, without departing from the spirit of the present invention, refer to the following examples, and replace, reorganize, and mix the features in several different embodiments to complete other implementations example.

本發明中針對「第一部件形成在第二部件上或上方」的敘述，其可以是指「第一部件與第二部件直接接觸」，也可以是指「第一部件與第二部件之間另存在有其他部件」，致使第一部件與第二部件並不直接接觸。此外，本發明中的各種實施例可能使用重複的元件符號和/或文字註記。使用這些重複的元件符號與文字註記是為了使敘述更簡潔和明確，而非用以指示不同的實施例及/或配置之間的關聯性。另外，針對本發明中所提及的空間相關的敘述詞彙，例如：「在...之下」、「在...之上」、「低」、「高」、「下方」、「上方」、「之下」、「之上」、「底」、「頂」和類似詞彙時，為便於敘述，其用法均在於描述圖式中一個部件或特徵與另一個（或多個）部件或特徵的相對關係。除了圖式中所顯示的擺向外，這些空間相關詞彙也用來描述半導體裝置在製作過程中、使用中以及操作時的可能擺向。舉例而言，當半導體裝置被旋轉180度時，原先設置於其他部件「上方」的某部件便會變成設置於其他部件「下方」。因此，隨著半導體裝置的擺向的改變（旋轉90度或其它角度），用以描述其擺向的空間相關敘述亦應透過對應的方式予以解釋。In the present invention, the description of "the first part is formed on or above the second part" may mean "the first part is in direct contact with the second part" or "between the first part and the second part" There are other parts" so that the first part is not in direct contact with the second part. In addition, various embodiments in the present disclosure may use repeated reference numerals and/or text. These repeated reference numerals and text are used for brevity and clarity of description, rather than to indicate associations between different embodiments and/or configurations. In addition, for the space-related descriptive words mentioned in the present invention, for example: "below", "above", "low", "high", "below", "above" "," "under", "above", "bottom", "top" and similar terms, for convenience of description, are used to describe the relationship between one component or feature in the drawings and another (or more) components or relative relationship of features. In addition to the pendulum shown in the drawings, these space-related terms are also used to describe the possible pendulum orientations of the semiconductor device during fabrication, use, and operation. For example, when a semiconductor device is rotated by 180 degrees, a component that was originally arranged "above" other components becomes arranged "below" other components. Therefore, as the swing direction of the semiconductor device is changed (rotated by 90 degrees or other angles), the space-related descriptions used to describe the swing direction should also be explained in a corresponding manner.

雖然本發明使用第一、第二、第三等用詞，以敘述種種元件、部件、區域、層、及/或區塊（section），但應了解此等元件、部件、區域、層、及/或區塊不應被此等用詞所限制。此等用詞僅是用以區分某一元件、部件、區域、層、及/或區塊與另一個元件、部件、區域、層、及/或區塊，其本身並不意含及代表該元件有任何之前的序數，也不代表某一元件與另一元件的排列順序、或是製造方法上的順序。因此，在不背離本發明之具體實施例之範疇下，下列所討論之第一元件、部件、區域、層、或區塊亦可以第二元件、部件、區域、層、或區塊等詞稱之。Although the terms first, second, third, etc. are used herein to describe various elements, components, regions, layers, and/or sections, it should be understood that such elements, components, regions, layers, and /or blocks should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, and/or block from another element, component, region, layer, and/or block, and do not by themselves imply or represent that element The presence of any preceding ordinal numbers does not imply the order in which an element is arranged relative to another element, or the order of the method of manufacture. Thus, a first element, component, region, layer, or block discussed below could be termed a second element, component, region, layer, or block without departing from the scope of the specific embodiments of the present invention. Of.

本發明中所提及的「約」或「實質上」之用語通常表示在一給定值或範圍的20%之內，較佳是10%之內，且更佳是5%之內，或3%之內，或2%之內，或1%之內，或0.5%之內。應注意的是，說明書中所提供的數量為大約的數量，亦即在沒有特定說明「約」或「實質上」的情況下，仍可隱含「約」或「實質上」之含義。The terms "about" or "substantially" as used herein generally mean within 20%, preferably within 10%, and more preferably within 5% of a given value or range, or Within 3%, or within 2%, or within 1%, or within 0.5%. It should be noted that the quantities provided in the specification are approximate quantities, that is, the meaning of "about" or "substantially" can still be implied without the specific description of "about" or "substantially".

請參照第1圖至第3圖所示，其繪示本發明第一實施例中微機電裝置的形成方法的示意圖。首先，如第1圖所示，提供一基底100，例如一塊狀矽基底（bulk silicon substrate），基底100例如包含單晶矽、多晶矽、非晶矽或其他合適的材質，但並不限於此。在一實施例中，該基底100具有一合適的厚度T1，例如是約為400微米（micrometers, μm）至500微米，但並不限於此。本領域具通常技藝者應可輕易理解，為了符合實際產品需求，基底100的厚度還可依據後續所形成之溝槽的預定深度進一步調整。Please refer to FIG. 1 to FIG. 3 , which are schematic diagrams of a method for forming a MEMS device according to a first embodiment of the present invention. First, as shown in FIG. 1, a substrate 100 is provided, such as a bulk silicon substrate. The substrate 100 includes, for example, monocrystalline silicon, polycrystalline silicon, amorphous silicon or other suitable materials, but not limited to this . In one embodiment, the substrate 100 has a suitable thickness T1, for example, about 400 micrometers (μm) to 500 micrometers, but not limited thereto. Those skilled in the art should easily understand that, in order to meet actual product requirements, the thickness of the substrate 100 can be further adjusted according to the predetermined depth of the grooves formed subsequently.

基底100具有兩相對表面，如第1圖所示的第一表面101以及第二表面102，基底100的第一表面101上還依序形成有一氧化層110以及一互連結構200。氧化層110例如包含氧化矽（silicon oxide, SiO）或二氧化矽（silicon dioxide, SiO₂ ），而互連結構200則可以是利用沉積及/或選擇性蝕刻材料層等習知半導體製程所形成之任何合適的半導體結構。互連結構200可包含至少一底電極（bottom electrode, 未繪示），設置在該底電極上的一頂電極（top electrode, 未繪示）、以及設置在該底電極與該頂電極之間的一壓電層（piezoelectric layer, 未繪示）。在一實施例中，互連結構200進一步包含堆疊於第一表面101上的至少一介電層201，埋設在至少一介電層201內的至少一金屬層203，以及電連接至少一金屬層203的至少一連接墊205，如第1圖所示，其中，至少一介電層201例如包含氮化矽（silicon nitride, SiN）或氮氧化矽（silicon oxynitride, SiON）等介電材質，至少一金屬層203例如包含銅（copper, Cu）、鉬（molybdenum, Mo）、鎢（tungsten, W）或鋁（aluminum, Al）等金屬材質，但不以此為限。The substrate 100 has two opposite surfaces, such as a first surface 101 and a second surface 102 shown in FIG. 1 , an oxide layer 110 and an interconnect structure 200 are formed on the first surface 101 of the substrate 100 in sequence. The oxide layer 110 includes, for example, silicon oxide (SiO) or silicon dioxide (SiO ₂ ), and the interconnect structure 200 may be formed by conventional semiconductor processes such as deposition and/or selective etching of material layers. any suitable semiconductor structure. The interconnect structure 200 may include at least a bottom electrode (not shown), a top electrode (not shown) disposed on the bottom electrode, and a top electrode disposed between the bottom electrode and the top electrode A piezoelectric layer (piezoelectric layer, not shown). In one embodiment, the interconnect structure 200 further includes at least one dielectric layer 201 stacked on the first surface 101 , at least one metal layer 203 embedded in the at least one dielectric layer 201 , and electrically connected to the at least one metal layer At least one connection pad 205 of 203, as shown in FIG. 1, wherein, at least one dielectric layer 201 includes, for example, a dielectric material such as silicon nitride (SiN) or silicon oxynitride (SiON), etc., at least A metal layer 203 includes metal materials such as copper (Cu), molybdenum (Mo), tungsten (W) or aluminum (Al), but not limited thereto.

需注意的是，互連結構200進一步包含設置在一懸掛區域210內的一穿孔207，藉此，設置在懸掛區域210內的一結構則可在後續製程中與基底100部分分離而形成一懸掛結構（suspended structure, 未繪示）。懸掛結構例如包含由上而下依序堆疊於互連結構200內的該頂電極、該壓電層以及該底電極，進而能夠在該微機電裝置進行操作時以特定頻率振動。在本實施例中，該懸掛結構可包含懸臂（cantilever）、隔膜（diaphragm）等類似結構，但並不限於此。It should be noted that the interconnection structure 200 further includes a through hole 207 disposed in a suspension area 210, whereby a structure disposed in the suspension area 210 can be partially separated from the substrate 100 to form a suspension in a subsequent process structure (suspended structure, not shown). The suspension structure includes, for example, the top electrode, the piezoelectric layer, and the bottom electrode sequentially stacked in the interconnect structure 200 from top to bottom, so as to vibrate at a specific frequency when the MEMS device operates. In this embodiment, the suspension structure may include a cantilever, a diaphragm and the like, but is not limited thereto.

接著，在互連結構200上形成一質量塊130，使質量塊130位在懸掛區域210的該懸掛結構上方。質量塊130可包含任何質量密度（mass density）較高的合適材料，如鋁銅（aluminum copper, AlCu）、銅、金（gold, Au）、鉑（platinum, Pt）、鉬或矽（silicon, Si）等，但不限於此。較佳地，質量塊130係設置在靠近穿孔207的位置，並且，質量塊130的長度L例如約為懸掛區域210之長度的1/2至1/3左右，以避免質量塊130的設置位置落在互連結構200的應力集中區內，而影響其剛性（stiffness）。而質量塊130的厚度較佳約為1微米至3微米，但不限於此。在一實施例中，質量塊130係形成在互連結構200的一頂介電層209內，舉例來說，質量塊130在設置時可選擇部分突出於頂介電層209的頂面，如第1圖所示，以獲得較大的質量。而在另一實施例中，質量塊（未繪示）在設置時亦可選擇不突出於頂介電層209的該頂面，而是與頂介電層209的該頂面共平面。Next, a mass 130 is formed on the interconnect structure 200 so that the mass 130 is located above the suspension structure in the suspension region 210 . The mass 130 may comprise any suitable material with high mass density, such as aluminum copper (AlCu), copper, gold (Au), platinum (Pt), molybdenum, or silicon (silicon, Si), etc., but not limited thereto. Preferably, the mass block 130 is arranged at a position close to the through hole 207 , and the length L of the mass block 130 is, for example, about 1/2 to 1/3 of the length of the suspension area 210 , so as to avoid the setting position of the mass block 130 . It falls within the stress concentration region of the interconnect structure 200 and affects its stiffness. The thickness of the mass block 130 is preferably about 1 μm to 3 μm, but not limited thereto. In one embodiment, the proof-mass 130 is formed in a top dielectric layer 209 of the interconnect structure 200. For example, the proof-mass 130 may be selected to partially protrude from the top surface of the top dielectric layer 209 when disposed, such as Figure 1 for a larger mass. In another embodiment, the proof mass (not shown) can also be selected not to protrude from the top surface of the top dielectric layer 209 when disposed, but to be coplanar with the top surface of the top dielectric layer 209 .

然後，如第2圖所示，自基底100的背側即第二表面102所在側形成一溝槽103。具體來說，先在第二表面102上形成一遮罩層（未繪示），以定義溝槽103的設置位置以及尺寸，再透過該遮罩層進行一蝕刻製程，移除一定程度的基底100直至部份暴露出下方的氧化層110。該遮罩層具有一開口，該開口較佳係對應於設置在懸掛區域210內的該懸掛結構，而該開口的尺寸則較佳係等同於溝槽103的預定尺寸，例如是約為100微米至150微米，但不以此為限。本領域具通常技藝者應可輕易理解，溝槽103的尺寸並不以前述為限，而可依據實際產品需求進一步調整。Then, as shown in FIG. 2 , a trench 103 is formed from the back side of the substrate 100 , that is, the side where the second surface 102 is located. Specifically, a mask layer (not shown) is first formed on the second surface 102 to define the location and size of the trenches 103 , and then an etching process is performed through the mask layer to remove a certain degree of substrate 100 until the underlying oxide layer 110 is partially exposed. The mask layer has an opening, and the opening preferably corresponds to the suspension structure disposed in the suspension region 210 , and the size of the opening is preferably equal to the predetermined size of the groove 103 , for example, about 100 μm to 150 microns, but not limited thereto. Those skilled in the art should easily understand that the size of the groove 103 is not limited to the above, and can be further adjusted according to actual product requirements.

換言之，溝槽103的製程是利用氧化層110作為一蝕刻停止層而進行，使得溝槽103可延伸於基底100的兩相對表面（第一表面101以及第二表面102）之間，進而對位於設置在第一表面101上之互連結構200的懸掛區域210內的該懸掛結構。如此，溝槽103可具有與基底100的厚度T1相同的一深度，並且，溝槽103在鄰接懸掛區域210的底面處則具有一開口103a，如第2圖所示。之後，則再進行另一蝕刻製程，移除被暴露出的部分氧化層110，使得位於下方之互連結構200的懸掛區域210的該底面可被暴露出來，並與溝槽103相互連通，如第2圖所示。需注意的是，在進行該另一蝕刻製程時，剩餘的氧化層110的側壁還可稍微被一併移除，以在鄰近溝槽103的開口103a處形成底切（under cut）部分111。In other words, the process of the trench 103 is performed using the oxide layer 110 as an etch stop layer, so that the trench 103 can extend between the two opposite surfaces (the first surface 101 and the second surface 102 ) of the substrate 100 , and furthermore The suspension structure in the suspension region 210 of the interconnect structure 200 disposed on the first surface 101 . In this way, the trench 103 can have the same depth as the thickness T1 of the substrate 100 , and the trench 103 has an opening 103 a adjacent to the bottom surface of the suspension region 210 , as shown in FIG. 2 . After that, another etching process is performed to remove the exposed part of the oxide layer 110, so that the bottom surface of the suspension region 210 of the underlying interconnect structure 200 can be exposed and communicated with the trench 103, such as shown in Figure 2. It should be noted that during the other etching process, the sidewalls of the remaining oxide layer 110 may also be slightly removed to form an undercut portion 111 adjacent to the opening 103 a of the trench 103 .

此外，在一實施例中，還可選擇在溝槽103形成之前，先額外在互連結構200上形成一保護層（protection layer, 未繪示），以保護設置在互連結構200內的元件，該保護層例如包含氧化矽或二氧化矽等材質。然後，在溝槽103形成並且移除被暴露出的部分氧化層110之後，再完全移除該保護層，以釋放位在互連結構200的懸掛區域210內的該懸掛結構。在此情況下，由於互連結構200的懸掛區域210內設有穿孔207，該懸掛結構的一端（亦可稱為自由端F）即不與基底100相連而呈現懸空的態樣，而該懸掛結構的另一端（亦可稱為錨端A）則仍然與基底100以及設置在基底100上的剩餘氧化層110相連接，如第2圖所示。In addition, in one embodiment, a protection layer (not shown) may be additionally formed on the interconnect structure 200 before the trench 103 is formed, so as to protect the elements disposed in the interconnect structure 200 , the protective layer includes materials such as silicon oxide or silicon dioxide, for example. Then, after the trench 103 is formed and the exposed part of the oxide layer 110 is removed, the protective layer is completely removed to release the suspension structure within the suspension region 210 of the interconnect structure 200 . In this case, since the through hole 207 is provided in the suspension area 210 of the interconnection structure 200, one end (also referred to as the free end F) of the suspension structure is not connected to the substrate 100 and is in a suspended state, and the suspension structure is suspended. The other end of the structure (also referred to as the anchor end A) is still connected to the substrate 100 and the remaining oxide layer 110 disposed on the substrate 100 , as shown in FIG. 2 .

由此，即可形成本發明第一實施例中的微機電裝置。在本實施例中，該微機電裝置包含設置在互連結構200的懸掛區域210內的懸掛結構、溝槽103以及質量塊130，因而可作為一微機電系統加速器，透過該懸掛結構內設置的壓電層而在接收到聲波或電訊號時產生相應的振動，並透過質量塊130調整該懸掛結構，使得該懸掛結構具有能符合所需感測之音頻範圍的共振頻率。值得注意的是，當該懸掛結構振動時，壓力以及振動會導致該懸掛結構發生形變，進而使該懸掛結構產生壓電反應。請參考第3圖所示的應力分布模式，其中，懸掛區域210內應力分布的強度係由點狀網底的密度來表示。一般來說，多數的應力會集中在該懸掛結構的該另一端（即錨端A），如第3圖所示。因此，本實施例的質量塊130是設置在鄰近該懸掛結構之該端（即自由端F）的位置，即設置在應力分布較小的區域。在此設置下，本實施例的質量塊130才不會影響位在懸掛區域210內的該懸掛結構的剛度。依據下方的公式（I），該微機電裝置的最小感測訊號（a_min ）係與質量塊130的質量正相關，是以，本實施例中設置有質量塊130的該微機電裝置才能夠應用於無線藍芽耳機，從而輔助麥克風的語音振動。公式（I）：

，其中，κ _B 為博爾茨曼常數（Boltzmann’s constant）；T為絕對溫度；ω₀ 為共振頻率；m_i 為感測器的質量；Q為質量係數。Thus, the MEMS device in the first embodiment of the present invention can be formed. In this embodiment, the MEMS device includes a suspension structure, a groove 103 and a mass 130 disposed in the suspension region 210 of the interconnect structure 200 , so that it can be used as a MEMS accelerator. The piezoelectric layer generates corresponding vibrations when receiving sound waves or electrical signals, and adjusts the suspension structure through the mass block 130 , so that the suspension structure has a resonance frequency that can meet the audio frequency range required for sensing. It is worth noting that when the suspension structure vibrates, the pressure and vibration will cause the suspension structure to deform, thereby causing the suspension structure to generate a piezoelectric response. Please refer to the stress distribution pattern shown in FIG. 3 , wherein the intensity of the stress distribution in the suspension area 210 is represented by the density of the dot-shaped mesh bottom. In general, most of the stress will be concentrated on the other end of the suspension structure (ie the anchor end A), as shown in Figure 3. Therefore, the mass 130 of the present embodiment is disposed at a position adjacent to the end (ie, the free end F) of the suspension structure, that is, in a region where the stress distribution is small. Under this setting, the mass 130 of this embodiment will not affect the stiffness of the suspension structure located in the suspension region 210 . According to the following formula (I), the minimum sensing signal (a _min ) of the MEMS device is positively correlated with the mass of the mass 130 . Therefore, the MEMS device provided with the mass 130 in this embodiment can only Applied to wireless bluetooth earphones to assist the voice vibration of the microphone. Formula (I):

, where κ _B is Boltzmann's constant; T is the absolute temperature; ω ₀ is the resonance frequency; _mi is the mass of the sensor; Q is the mass coefficient.

本領域具通常知識者也應了解，本發明的微機電裝置及其形成方法並不限於前述，而可具有其他態樣或變化。舉例來說，雖然前述製程中，是將該微機電裝置形成於一塊狀矽基底作為實施態樣進行說明，但其實際製程並不以此為限，而可選擇另外在一矽覆絕緣基底（silicon-on-insulator substrate, SOI substrate）上進行操作。下文將針對本發明微機電裝置及其形成方法的其他實施例或變化型進行說明。且為簡化說明，以下說明主要針對各實施例不同之處進行詳述，而不再對相同之處作重覆贅述。此外，本發明之各實施例中相同之元件係以相同之標號進行標示，以利於各實施例間互相對照。Those skilled in the art should also understand that the MEMS device and the method for forming the same of the present invention are not limited to the foregoing, and may have other aspects or variations. For example, although the foregoing process describes the MEMS device formed on a silicon substrate as an embodiment, the actual process is not limited to this, and another silicon-on-insulator substrate can be selected. (silicon-on-insulator substrate, SOI substrate). Other embodiments or variations of the microelectromechanical device of the present invention and the method for forming the same will be described below. In order to simplify the description, the following description mainly focuses on the differences of the embodiments, and does not repeat the same points. In addition, the same elements in the various embodiments of the present invention are marked with the same reference numerals, so as to facilitate the mutual comparison of the various embodiments.

而本發明的另一實施例，則另公開一種微機電裝置及其形成方法，其是在微機電裝置的最小感測訊號（a_min ）與該質量塊的質量正相關，並且，該質量塊的質量又與懸掛區域210內的懸掛結構的剛性相關的前提下，進一步提供質量更為優化（質量更重）但不至於影響該懸掛結構的剛度的質量塊。請參照第4圖至第7圖所示，其繪示本發明第二實施例中微機電裝置的形成方法的示意圖。本實施例的形成方法在步驟上大體上與前述實施例相似，而相似之處容不再贅述。而本實施例與前述實施例之間的主要差異處在於，本實施例的質量塊330係部分懸掛地設置在互連結構200上方。Another embodiment of the present invention further discloses a MEMS device and a method for forming the same, wherein the minimum sensing signal (a _min ) of the MEMS device is positively correlated with the mass of the mass, and the mass On the premise that the mass of the suspension structure is related to the rigidity of the suspension structure in the suspension area 210, a mass block with more optimized mass (heavier mass) but not affecting the rigidity of the suspension structure is further provided. Please refer to FIG. 4 to FIG. 7 , which are schematic diagrams of a method for forming a MEMS device according to a second embodiment of the present invention. The steps of the forming method of this embodiment are generally similar to those of the previous embodiment, and the similarities will not be repeated. The main difference between the present embodiment and the previous embodiments is that the mass 330 of the present embodiment is partially suspended above the interconnection structure 200 .

如第4圖所示，基底100同樣具有第一表面101以及第二表面102，而基底100的第一表面101上依序形成有一氧化層110以及一互連結構200。需注意的是，關於本實施例中基底100、氧化層110以及互連結構200的細部特徵大體上與前述第一實施例相同，容不再贅述。接著，在頂介電層209的該頂面上形成一基礎材料層（base material layer）331，基礎材料層331進一步填入穿孔207內，如第4圖所示。在一實施例中，基礎材料層331例如包含氧化矽或二氧化矽等材質，但不以此為限。As shown in FIG. 4 , the substrate 100 also has a first surface 101 and a second surface 102 , and an oxide layer 110 and an interconnect structure 200 are sequentially formed on the first surface 101 of the substrate 100 . It should be noted that the detailed features of the substrate 100 , the oxide layer 110 , and the interconnection structure 200 in this embodiment are generally the same as those in the aforementioned first embodiment, and will not be repeated here. Next, a base material layer 331 is formed on the top surface of the top dielectric layer 209 , and the base material layer 331 is further filled into the through holes 207 , as shown in FIG. 4 . In one embodiment, the base material layer 331 includes materials such as silicon oxide or silicon dioxide, but not limited thereto.

然後，如第5圖所示，在基礎材料層331以及頂介電層209內形成至少一開孔，該至少一開孔係位在懸掛區域210的範圍內。較佳地，該至少一開孔形成在該懸掛結構上鄰近穿孔207的位置。在本實施例中，係形成一個開孔，該開孔從一俯視圖（未繪示）來看可具有環狀外觀，而從一剖面圖來看則可呈現相互分離的兩孔332，如第5圖所示，但該開孔的設置方式與態樣並不限於此。也就是說，當從一個由上而下的視角查看時，前述相互分離的兩孔332可能彼此相連，但並不以此為限。在另一實施例中，亦可依據實際製程需求而在鄰近穿孔207的位置形成各種數量的開孔。之後，則在基礎材料層331上再形成一質量層（mass layer）333，質量層333同樣是形成在懸掛區域210的範圍內，並進一步填入前述的孔332之內而形成突出部333a，使得突出部333a可環繞在一部分的基礎材料層331的外側，如第5圖所示。質量層333的形成可包含以下步驟，首先，在基礎材料層331上形成一質量材料層（mass material layer, 未繪示），使得該質量材料層整體覆蓋在基礎材料層331的所有表面上，再圖案化該質量材料層，形成第5圖所示的質量層333。在一實施例中，質量層333包含任何質量密度較高的合適材料，如鋁銅、銅、金、鉑、鉬或矽，但不限於此。需注意的是，質量層333可具有相對較大的厚度，使得質量層333與下方基礎材料層331的整體厚度T2可約為5微米至15微米，較佳為10微米，但不以此為限。除此之外，質量層333的厚度還可單獨地依照位在互連結構200表面的連接墊的厚度進行調整。Then, as shown in FIG. 5 , at least one opening is formed in the base material layer 331 and the top dielectric layer 209 , and the at least one opening is located within the range of the suspension region 210 . Preferably, the at least one opening is formed on the suspension structure at a position adjacent to the through hole 207 . In this embodiment, an opening is formed, and the opening can have a ring-shaped appearance from a top view (not shown), and can show two holes 332 separated from each other from a cross-sectional view, such as the first 5, but the arrangement and aspect of the openings are not limited to this. That is, when viewed from a top-down perspective, the aforementioned two mutually separated holes 332 may be connected to each other, but not limited thereto. In another embodiment, various numbers of openings can also be formed at positions adjacent to the through holes 207 according to actual process requirements. After that, a mass layer 333 is formed on the base material layer 331. The mass layer 333 is also formed in the range of the suspension region 210, and is further filled into the aforementioned holes 332 to form the protrusions 333a. The protruding portion 333a can surround the outer side of a part of the base material layer 331, as shown in FIG. 5 . The formation of the mass layer 333 may include the following steps. First, a mass material layer (not shown) is formed on the base material layer 331, so that the mass material layer entirely covers all surfaces of the base material layer 331, The mass material layer is then patterned to form the mass layer 333 shown in FIG. 5 . In one embodiment, the mass layer 333 includes any suitable material with high mass density, such as, but not limited to, aluminum copper, copper, gold, platinum, molybdenum, or silicon. It should be noted that the quality layer 333 may have a relatively large thickness, so that the overall thickness T2 of the quality layer 333 and the underlying base material layer 331 may be about 5 μm to 15 μm, preferably 10 μm, but not limited to this. limit. Besides, the thickness of the quality layer 333 can be independently adjusted according to the thickness of the connection pads on the surface of the interconnect structure 200 .

如第6圖所示，自基底100的背側即第二表面102所在側形成一溝槽103。具體來說，在形成溝槽103之前，係先在互連結構200上形成一保護層350，覆蓋質量層333、基礎材料層331以及互連結構200，進而保護設置於下方的元件。保護層350例如包含氧化矽、二氧化矽、或是與下方基礎材料層331的材質具有相同或相近蝕刻選擇比的其他材質等。然後，在第二表面102上形成一遮罩層（未繪示），以定義溝槽103的設置位置以及尺寸，再透過該遮罩層自基底100的該背側進行一蝕刻製程，例如是一非等向性乾蝕刻製程，以移除一定程度的基底100直至部份暴露出下方的氧化層110。在一實施例中，該遮罩層具有一開口，該開口較佳係對應於設置在懸掛區域210內的該懸掛結構，而該開口的尺寸則較佳係等同於溝槽103的預定尺寸，例如是約為100微米至150微米，但不以此為限。As shown in FIG. 6 , a trench 103 is formed from the backside of the substrate 100 , that is, the side where the second surface 102 is located. Specifically, before the trench 103 is formed, a protective layer 350 is first formed on the interconnect structure 200 to cover the quality layer 333 , the base material layer 331 and the interconnect structure 200 , thereby protecting the underlying elements. The protective layer 350 includes, for example, silicon oxide, silicon dioxide, or other materials having the same or similar etching selectivity as the material of the underlying base material layer 331 . Then, a mask layer (not shown) is formed on the second surface 102 to define the location and size of the trenches 103, and then an etching process is performed from the back side of the substrate 100 through the mask layer, such as An anisotropic dry etching process is performed to remove a certain extent of the substrate 100 until a portion of the underlying oxide layer 110 is exposed. In one embodiment, the mask layer has an opening, and the opening preferably corresponds to the suspension structure disposed in the suspension area 210 , and the size of the opening is preferably equal to the predetermined size of the groove 103 , For example, it is about 100 microns to 150 microns, but not limited thereto.

藉此，利用氧化層110作為一蝕刻停止層而在基底100內形成溝槽103，使得溝槽103可延伸於基底100的兩相對表面（第一表面101以及第二表面102）之間，並且具有與基底100的厚度T1相同的一深度，此外，溝槽103可對位於設置在第一表面101上之互連結構200的懸掛區域210內的該懸掛結構，且溝槽103在鄰近懸掛區域210的底面處則具有一開口103a，如第6圖所示。Thereby, the trench 103 is formed in the substrate 100 by using the oxide layer 110 as an etch stop layer, so that the trench 103 can extend between two opposite surfaces (the first surface 101 and the second surface 102 ) of the substrate 100 , and Having a depth that is the same as the thickness T1 of the substrate 100 , in addition, the trenches 103 may correspond to the suspension structures located in the suspension regions 210 of the interconnect structure 200 disposed on the first surface 101 , and the trenches 103 are adjacent to the suspension regions. The bottom surface of 210 has an opening 103a, as shown in FIG. 6 .

之後，如第7圖所示，進行另一蝕刻製程，例如是一等向性濕蝕刻製程，以移除自溝槽103所暴露出的部分氧化層110，使得位於下方的懸掛區域210的該底面可被部分暴露出來，而可與溝槽103相互連通。需注意的是，在進行該另一蝕刻製程時，剩餘的氧化層110的側壁還可稍微地被一併移除，以在鄰近溝槽103的開口103a處形成底切部分111。而後，則移除保護層350以及基礎材料層331，藉此釋放互連結構200的懸掛區域210內的該懸掛結構。如此，該懸掛結構的一端（亦可稱為自由端F）即不與基底100相連而呈現懸空的態樣，而該懸掛結構的另一端（亦可稱為錨端A）則仍然與基底100相連接，使得該微機電裝置在進行操作而使該懸掛結構產生振動時，較多的應力應會集中在該懸掛結構的該錨端A，而較少的應力則會集中在該懸掛結構的該自由端F。Afterwards, as shown in FIG. 7, another etching process, such as an isotropic wet etching process, is performed to remove the part of the oxide layer 110 exposed from the trench 103, so that the part of the oxide layer 110 exposed from the trench 103 is The bottom surface may be partially exposed and communicate with the groove 103 . It should be noted that during the other etching process, the sidewalls of the remaining oxide layer 110 may also be slightly removed to form the undercut portion 111 adjacent to the opening 103 a of the trench 103 . Then, the protective layer 350 and the base material layer 331 are removed, thereby releasing the suspension structure in the suspension region 210 of the interconnection structure 200 . In this way, one end (also referred to as the free end F) of the suspension structure is not connected to the base 100 and appears in a suspended state, while the other end (also referred to as the anchor end A) of the suspension structure is still connected to the base 100 are connected, so that when the MEMS device is operated to cause the suspension structure to vibrate, more stress should be concentrated on the anchor end A of the suspension structure, and less stress will be concentrated on the anchor end A of the suspension structure. The free end F.

在一實施例中，保護層350以及基礎料材層331可選擇在移除部分暴露的氧化層110時一併被移除，但不限於此。在另一實施例中，保護層350以及基礎料材層331亦可選擇由另一等向性濕蝕刻製程額外地進行移除。需注意的是，在移除保護層350以及基礎料材層331時，係完全移除保護層350以及大部分的基礎料材層331，而僅留下被質量層333的突出部333a所環繞之該部分的基礎材料層331，藉此，即可形成如第7圖所示的基礎層331a。藉此，基礎層331a以及質量層333可共同形成本實施例的質量塊330。本實施例的質量塊330包含一雙層結構，其中，基礎層331a以及環繞於基礎層331a外側的突出部333a係設置在該雙層結構的底層，而設置在基礎層331a以及突出部333a上方的質量層333則是位在該雙層結構的頂層。需注意的是，質量塊330中僅有其底層（基礎層331a以及突出部333a）是直接設置在懸掛區域210的該懸掛結構上，並設置在鄰近該懸掛結構的自由端F的位置，而質量塊330的該頂層（質量層333）則可以自該懸掛結構的自由端F進一步延伸到錨端A，使得該頂層的一端可懸空於錨端A之上，如第7圖所示。In one embodiment, the protective layer 350 and the base material layer 331 may be optionally removed together with the partially exposed oxide layer 110 , but not limited thereto. In another embodiment, the protective layer 350 and the base material layer 331 may be additionally removed by another isotropic wet etching process. It should be noted that when the protective layer 350 and the base material layer 331 are removed, the protective layer 350 and most of the base material layer 331 are completely removed, and only the protrusions 333 a of the quality layer 333 are left surrounded by This part of the base material layer 331 is removed, whereby the base layer 331a as shown in FIG. 7 can be formed. Thereby, the base layer 331a and the mass layer 333 can jointly form the mass 330 of the present embodiment. The mass 330 of this embodiment includes a double-layer structure, wherein the base layer 331a and the protrusions 333a surrounding the outside of the base layer 331a are disposed on the bottom layer of the double-layer structure, and are disposed above the base layer 331a and the protrusions 333a The quality layer 333 is located on the top layer of the double-layer structure. It should be noted that, in the mass block 330, only the bottom layer (the base layer 331a and the protruding portion 333a) is directly disposed on the suspension structure of the suspension region 210, and is disposed adjacent to the free end F of the suspension structure, while The top layer (mass layer 333 ) of the mass block 330 can further extend from the free end F of the suspension structure to the anchor end A, so that one end of the top layer can be suspended above the anchor end A, as shown in FIG. 7 .

由此，即可形成本發明第二實施例中的微機電裝置。在本實施例中，該微機電裝置包含設置在互連結構200的懸掛區域210內的懸掛結構、溝槽103以及質量塊330，同樣可作為一微機電系統加速器，透過該懸掛結構內設置的壓電層而在接收到聲波或電訊號時能夠振動，並透過質量塊330調整該懸掛結構，使得該懸掛結構具有能符合所需感測之音頻範圍的共振頻率。值得說明的是，本實施例的質量塊330包含一雙層結構，該雙層結構由一底層（基礎層331a以及突出部333a）以及頂層（質量層333）構成，使得該頂層可以自該懸掛結構的自由端F延伸到錨端A，使得本實施例的質量層330可兼具較大的厚度T2、較大的尺寸、以及較大的質量等優點。其中，質量塊330的厚度T2例如是約為前述第一實施例中質量塊130厚度的5至10倍左右，例如是約為5微米至15微米，較佳為10微米，但不以此為限。此外，本實施例的質量塊330僅其底層（基礎層331a以及突出部333a）是直接設置在該懸掛結構上，並位在該懸掛結構中應力分布較少的區域內（即靠近自由端F的區域），而質量塊330的該頂層（質量層333）則可一端懸空地設置在錨端A之上，而未直接接觸該懸掛結構的應力集中區域。由此，本實施例中具有較大厚度、較大尺寸以及較大質量的質量塊330不會影響位在懸掛區域210內的該懸掛結構的剛度，從而可提供更為優化的感測靈敏度。是以，本發明具有前述質量塊330的微機電裝置能夠應用於無線藍芽耳機，從而輔助麥克風的語音振動。Thus, the MEMS device in the second embodiment of the present invention can be formed. In this embodiment, the MEMS device includes a suspension structure, a groove 103 and a mass 330 disposed in the suspension region 210 of the interconnect structure 200 , and can also be used as a MEMS accelerator. The piezoelectric layer can vibrate when receiving sound waves or electrical signals, and the suspension structure is adjusted through the mass block 330 so that the suspension structure has a resonance frequency that can meet the audio frequency range required for sensing. It should be noted that the mass block 330 of this embodiment includes a double-layer structure, and the double-layer structure is composed of a bottom layer (the base layer 331a and the protruding portion 333a ) and a top layer (the mass layer 333 ), so that the top layer can be suspended from the The free end F of the structure extends to the anchor end A, so that the quality layer 330 of this embodiment can have the advantages of a larger thickness T2, a larger size, and a larger mass. The thickness T2 of the mass block 330 is, for example, about 5 to 10 times the thickness of the mass block 130 in the first embodiment, for example, about 5 microns to 15 microns, preferably 10 microns, but not limited to this. limit. In addition, only the bottom layer (the base layer 331a and the protruding portion 333a) of the mass 330 in this embodiment is directly disposed on the suspension structure, and is located in the area of the suspension structure with less stress distribution (that is, close to the free end F). area), and the top layer (mass layer 333 ) of the mass block 330 may be suspended above the anchor end A at one end without directly contacting the stress concentration area of the suspension structure. Therefore, in this embodiment, the mass 330 having a larger thickness, a larger size and a larger mass will not affect the stiffness of the suspension structure located in the suspension region 210 , thereby providing more optimized sensing sensitivity. Therefore, the micro-electromechanical device having the aforementioned mass 330 of the present invention can be applied to a wireless bluetooth earphone, thereby assisting the voice vibration of the microphone.

請參照第8圖所示，其繪示本發明第三實施例中微機電裝置的形成方法的示意圖。本實施例的形成方法在步驟上大體上與前述第二實施例相似，而相似之處容不再贅述。而本實施例與前述實施例之間的主要差異處在於，質量塊530的質量層533僅位在雙層結構的頂層，而不會向下延伸並環繞位在該雙層結構底層的基礎層531周圍。Please refer to FIG. 8 , which is a schematic diagram of a method for forming a MEMS device according to a third embodiment of the present invention. The forming method of this embodiment is generally similar to the foregoing second embodiment in steps, and the similarities will not be repeated. The main difference between this embodiment and the previous embodiments is that the mass layer 533 of the mass block 530 is only located on the top layer of the double-layer structure, and does not extend downward and surround the base layer located at the bottom layer of the double-layer structure. Around 531.

具體來說，本實施例的質量層533是直接形成在如第4圖所示的基礎材料層331上。接著，類似於前述第二實施例中的製程，在形成保護層350後，繼續形成溝槽103，再透過一等向性濕蝕刻製程移除氧化層110、保護層350以及基礎材料層331。需注意的是，在透過該等向性濕蝕刻製程移除本實施例中的基礎材料層時，需進一步控制蝕刻速率、蝕刻時間等蝕刻條件，以形成如第8圖所示的基礎層531，使得基礎層531僅會形成在應力分布較少的區域（即靠近自由端F的區域），而不致使所有的該基礎材料層皆被移除。在此情況下，基礎層531以及質量層533同樣可共同形成本實施例的質量塊530，而質量塊530則同樣是設置在鄰近該懸掛結構的自由端F的位置，而不會影響位在懸掛區域210內的該懸掛結構的剛度。Specifically, the quality layer 533 of this embodiment is directly formed on the base material layer 331 as shown in FIG. 4 . Next, similar to the process in the second embodiment, after the protective layer 350 is formed, the trench 103 is continuously formed, and the oxide layer 110 , the protective layer 350 and the base material layer 331 are removed through an isotropic wet etching process. It should be noted that when the base material layer in this embodiment is removed through the isotropic wet etching process, etching conditions such as etching rate and etching time need to be further controlled to form the base layer 531 as shown in FIG. 8 . , so that the base layer 531 is only formed in a region with less stress distribution (ie, a region close to the free end F), so that all the base material layers are not removed. In this case, the base layer 531 and the mass layer 533 can also jointly form the mass block 530 of the present embodiment, and the mass block 530 is also disposed adjacent to the free end F of the suspension structure without affecting the position in the suspension structure. The stiffness of the suspension structure within the suspension region 210 .

由此，即可形成本發明第三實施例中的微機電裝置，該微機電裝置同樣包含設置在互連結構200的懸掛區域210內的懸掛結構、溝槽103以及質量塊530，同樣可作為一微機電系統加速器，透過該懸掛結構內設置的壓電層而在接收到聲波或電訊號時能夠振動，並透過質量塊530調整該懸掛結構，使得該懸掛結構具有能符合所需感測之音頻範圍的共振頻率。需注意的是，本實施例的質量塊530同樣具有較大的尺寸、較大的質量以及較大的厚度T2，而質量塊530的厚度T2例如是約為5微米至15微米，但不以此為限。並且，本實施例中具有較大厚度、較大尺寸以及較大質量的質量塊530不會影響位在懸掛區域210內的該懸掛結構的剛度，從而可提供更為優化的感測靈敏度。是以，本發明具有前述質量塊530的微機電裝置能夠應用於無線藍芽耳機，從而輔助麥克風的語音振動。Thus, the MEMS device in the third embodiment of the present invention can be formed. The MEMS device also includes the suspension structure, the groove 103 and the mass 530 disposed in the suspension region 210 of the interconnection structure 200 , which can also be used as A micro-electromechanical system accelerator can vibrate when receiving sound waves or electrical signals through the piezoelectric layer disposed in the suspension structure, and adjust the suspension structure through the mass block 530, so that the suspension structure has a characteristic that can meet the required sensing. The resonant frequency of the audio range. It should be noted that the proof block 530 of this embodiment also has a larger size, a larger mass and a larger thickness T2, and the thickness T2 of the proof block 530 is, for example, about 5 to 15 μm, but not limited to This is limited. Moreover, the mass 530 having a larger thickness, a larger size and a larger mass in this embodiment will not affect the rigidity of the suspension structure located in the suspension region 210, thereby providing more optimized sensing sensitivity. Therefore, the micro-electromechanical device having the aforementioned mass 530 of the present invention can be applied to a wireless bluetooth earphone, so as to assist the voice vibration of the microphone.

整體來說，本發明提供一種具有雙層結構的檢測質量塊，該質量塊的底層係直接設置在位於懸掛區域內的懸掛結構上，並位在該懸掛結構上應力分布較少的區域內，而該質量塊的頂層則設置在該底層上。如此，該質量塊的該頂層的一端則會直接設置在該底層上，而該頂層的另一端則進一步延伸並懸空地設置在該懸掛結構之上，而並未直接接觸位在該懸掛區域內的該懸掛結構。藉此，本發明可在避免影響該懸掛結構的剛性的前提下，充分擴大該質量塊的尺寸、質量、以及厚度等，而有利於提高該微機電裝置的感測靈敏度。是以，本發明具有前述質量塊的微機電裝置即能夠應用於無線藍芽耳機，從而輔助麥克風的語音振動。此外，本領域具通常知識者應可輕易了解，雖然本發明的前述實施例中是以雙層結構的質量塊作為實施樣態進行說明，但該質量塊的實際結構並不以此為限。在另一實施例中，亦可選擇形成具有多層結構的質量塊，同樣可呈現部分懸空設置的態樣，而懸掛地設置在該懸掛結構的應力集中區域的上，以在提高該微機電裝置的感測靈敏度之餘，避免對該懸掛結構的剛性造成影響。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。In general, the present invention provides a proof mass with a double-layer structure, the bottom layer of the proof mass is directly arranged on the suspension structure located in the suspension area, and is located in the area with less stress distribution on the suspension structure, The top layer of the mass is placed on the bottom layer. In this way, one end of the top layer of the mass block is directly disposed on the bottom layer, and the other end of the top layer is further extended and suspended above the suspension structure without directly touching the suspension area. of the suspension structure. In this way, the present invention can fully enlarge the size, mass, and thickness of the mass block without affecting the rigidity of the suspension structure, thereby improving the sensing sensitivity of the MEMS device. Therefore, the micro-electromechanical device having the aforementioned mass block of the present invention can be applied to wireless bluetooth earphones, so as to assist the voice vibration of the microphone. In addition, those skilled in the art should easily understand that although the above-mentioned embodiment of the present invention uses a mass block with a double-layer structure as an implementation mode, the actual structure of the mass block is not limited thereto. In another embodiment, a mass block with a multi-layer structure can also be selected, which can also be partially suspended, and is suspended on the stress concentration area of the suspension structure, so as to improve the performance of the MEMS device. In addition to the high sensing sensitivity, the rigidity of the suspension structure is avoided. The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

100:基底 101:第一表面 102:第二表面 103:溝槽 103a:開口 110:氧化層 111:底切部分 200:互連結構 201:介電層 203:金屬層 205:連接墊 207:穿孔 209:頂介電層 210:懸掛區域 130:質量塊 330:質量塊 331:基礎材料層 331a:基礎層 332:孔 333:質量層 333a:突出部 350:保護層 530:質量塊 531:基礎層 533:質量層 A:錨端 F:自由端 L:長度 T1、T2:厚度100: base 101: First Surface 102: Second Surface 103: Groove 103a: Opening 110: oxide layer 111: Undercut part 200: Interconnect Structure 201: Dielectric Layer 203: Metal Layer 205: Connection pad 207: Perforation 209: Top Dielectric Layer 210: Hanging Area 130: Mass Block 330: Mass Block 331: Basic Material Layer 331a: Base Layers 332: Hole 333: Quality Layer 333a: Protrusion 350: Protective layer 530: Mass Block 531: Base Layer 533: Quality Layer A: Anchor end F: free end L: length T1, T2: Thickness

第1圖為本發明一微機電裝置（MEMS device）於形成質量塊（proof mass）後的剖面示意圖。第2圖為本發明一微機電裝置於形成溝槽（cavity）後的剖面示意圖。第3圖為一懸掛區域的應力分布模擬示意圖。第4圖為本發明一微機電裝置於形成互連結構（interconnection structure）後的剖面示意圖。第5圖為本發明一微機電裝置於形成質量層後的剖面示意圖。第6圖為本發明一微機電裝置於形成溝槽後的剖面示意圖。第7圖為本發明一微機電裝置於形成質量塊後的剖面示意圖。第8圖為本發明一微機電裝置於形成質量塊後的另一剖面示意圖。FIG. 1 is a schematic cross-sectional view of a MEMS device of the present invention after a proof mass is formed. FIG. 2 is a schematic cross-sectional view of a MEMS device of the present invention after a cavity is formed. FIG. 3 is a schematic diagram of the stress distribution simulation of a suspension area. FIG. 4 is a schematic cross-sectional view of a MEMS device of the present invention after an interconnection structure is formed. FIG. 5 is a schematic cross-sectional view of a MEMS device of the present invention after the quality layer is formed. FIG. 6 is a schematic cross-sectional view of a MEMS device of the present invention after the trenches are formed. FIG. 7 is a schematic cross-sectional view of a microelectromechanical device of the present invention after a mass is formed. FIG. 8 is another schematic cross-sectional view of a microelectromechanical device of the present invention after a mass is formed.

100:基底100: base

101:第一表面101: First Surface

102:第二表面102: Second Surface

103:溝槽103: Groove

103a:開口103a: Opening

110:氧化層110: oxide layer

111:底切部分111: Undercut part

200:互連結構200: Interconnect Structure

201:介電層201: Dielectric Layer

203:金屬層203: Metal Layer

205:連接墊205: Connection pad

207:穿孔207: Perforation

209:頂介電層209: Top Dielectric Layer

210:懸掛區域210: Hanging Area

330:質量塊330: Mass Block

331a:基礎層331a: Base Layers

333:質量層333: Quality Layer

333a:突出部333a: Protrusion

A:錨端A: Anchor end

F:自由端F: free end

T1、T2:厚度T1, T2: Thickness

Claims

一種微機電裝置，包含：一基底，具有一第一表面以及相對於該第一表面的一第二表面；一溝槽，設置在該基底內，該溝槽延伸於該第一表面以及該第二表面之間；一互連結構，設置在該基底的該第一表面上，並且位在該溝槽的上方；以及一質量塊，設置在該互連結構上，其中，該質量塊係部分懸掛於該互連結構的上方。A microelectromechanical device, comprising: a substrate having a first surface and a second surface opposite to the first surface; a groove, disposed in the substrate, the groove extending between the first surface and the second surface; an interconnect structure disposed on the first surface of the substrate and over the trench; and A mass is disposed on the interconnecting structure, wherein the mass is partially suspended above the interconnecting structure.

如申請專利範圍第1項所述的微機電裝置，其中該質量塊包含一基礎層以及一質量層，該基礎層直接設置在該互連結構上，該質量層設置在該基礎層上。The MEMS device of claim 1, wherein the mass block comprises a base layer and a mass layer, the base layer is directly disposed on the interconnect structure, and the mass layer is disposed on the base layer.

如申請專利範圍第2項所述的微機電裝置，其中，該質量層的一端位在該基礎層上，該質量層的另一端則懸掛在該互連結構上。The MEMS device of claim 2, wherein one end of the mass layer is located on the base layer, and the other end of the mass layer is suspended on the interconnect structure.

如申請專利範圍第2項所述的微機電裝置，其中，質量層還包含一突出部，該突出部環繞該基礎層的一側壁。The MEMS device of claim 2, wherein the quality layer further includes a protruding portion surrounding a side wall of the base layer.

如申請專利範圍第4項所述的微機電裝置，其中，該突出部直接接觸該互連結構。The MEMS device of claim 4, wherein the protrusion directly contacts the interconnect structure.

如申請專利範圍第2項所述的微機電裝置，其中，該互連結構還包含一懸掛區域，該懸掛區域對應該溝槽，該懸掛區域的一第一端與該基底直接連接，該懸掛區域的一第二端未與該基底直接連接。The MEMS device of claim 2, wherein the interconnect structure further comprises a suspension area, the suspension area corresponds to the groove, a first end of the suspension area is directly connected to the substrate, and the suspension area is directly connected to the substrate. A second end of the region is not directly connected to the substrate.

如申請專利範圍第6項所述的微機電裝置，其中，該基礎層設置在鄰接該懸掛區域的該第二端的位置。The MEMS device of claim 6, wherein the base layer is disposed adjacent to the second end of the suspension region.

如申請專利範圍第6項所述的微機電裝置，其中，該質量層自該懸掛區域的該第一端延伸至該懸掛區域的該第二端。The MEMS device of claim 6, wherein the quality layer extends from the first end of the suspension area to the second end of the suspension area.

如申請專利範圍第1項所述的微機電裝置，更包含一氧化層，該氧化層設置在該互連結構以及該基底之間。The MEMS device as described in claim 1, further comprising an oxide layer disposed between the interconnection structure and the substrate.

如申請專利範圍第1項所述的微機電裝置，其中，該溝槽的厚度與該基底的厚度相同。The MEMS device of claim 1, wherein the thickness of the trench is the same as the thickness of the substrate.

如申請專利範圍第1項所述的微機電裝置，其中，該質量塊的至少一端懸掛在該互連結構的上方。The MEMS device of claim 1, wherein at least one end of the mass is suspended above the interconnect structure.

一種微機電裝置的形成方法，包含：提供一基底，該基底具有一第一表面以及相對於該第一表面的一第二表面；於該基底內形成一溝槽，該溝槽延伸於該第一表面以及該第二表面之間；於該基底的該第一表面上形成一互連結構，該互連結構位在該溝槽的上方；以及於該互連結構上形成一質量塊，其中，該質量塊係部分懸掛於該互連結構的上方。A method for forming a microelectromechanical device, comprising: providing a substrate having a first surface and a second surface opposite to the first surface; forming a groove in the substrate, the groove extending between the first surface and the second surface; forming an interconnect structure on the first surface of the substrate, the interconnect structure overlying the trench; and A mass is formed on the interconnecting structure, wherein the mass is partially suspended above the interconnecting structure.

如申請專利範圍第12項所述微機電裝置的形成方法，其中，該質量塊的形成是在該溝槽形成之後。The method for forming a microelectromechanical device according to claim 12, wherein the proof mass is formed after the trench is formed.

如申請專利範圍第12項所述微機電裝置的形成方法，其中，該質量塊的形成還包含：於該互連結構上形成一基礎層；以及形成一質量層。The method for forming a microelectromechanical device according to item 12 of the claimed scope, wherein the forming of the mass further comprises: forming a base layer on the interconnect structure; and A quality layer is formed.

如申請專利範圍第14項所述微機電裝置的形成方法，還包含：於該互連結構上形成一基礎材料層；在該溝槽形成之前，於該基礎材料層上形成該質量層；以及在該溝槽形成之後，部分移除該基礎材料層，形成該基礎層。The method for forming a microelectromechanical device as described in item 14 of the claimed scope further includes: forming a base material layer on the interconnect structure; forming the quality layer on the base material layer before the trench is formed; and After the trench is formed, the base material layer is partially removed to form the base layer.

如申請專利範圍第15項所述微機電裝置的形成方法，還包含：在該溝槽形成之前，於該基礎層上形成一穿孔；以及形成該質量層，該質量層包含設置於該穿孔內的一突出部。The method for forming a microelectromechanical device as described in item 15 of the claimed scope further includes: forming a through hole in the base layer before the trench is formed; and The quality layer is formed, and the quality layer includes a protrusion disposed in the through hole.

如申請專利範圍第16項所述微機電裝置的形成方法，其中，該突出部環繞該基礎層的一側壁，並直接接觸該互連結構。The method for forming a microelectromechanical device as claimed in claim 16, wherein the protruding portion surrounds a sidewall of the base layer and directly contacts the interconnection structure.

如申請專利範圍第12項所述微機電裝置的形成方法，還包含：形成一氧化層，該氧化層位在該互連結構以及該基底之間；以及形成該溝槽後，部分移除該氧化層，以連通該溝槽以及該內連結構。The method for forming a microelectromechanical device as described in item 12 of the claimed scope further includes: forming an oxide layer between the interconnect structure and the substrate; and After the trench is formed, the oxide layer is partially removed to connect the trench and the interconnect structure.

如申請專利範圍第12項所述微機電裝置的形成方法，其中，該溝槽的包含：自該第二表面部分移除該基底。The method for forming a microelectromechanical device according to item 12 of the claimed scope, wherein the grooves include: The substrate is partially removed from the second surface.

如申請專利範圍第12項所述微機電裝置的形成方法，其中，該質量塊的至少一端懸掛在該互連結構的上方。The method for forming a microelectromechanical device as claimed in claim 12, wherein at least one end of the mass is suspended above the interconnecting structure.