TWI844794B

TWI844794B - Acoustic wave device

Info

Publication number: TWI844794B
Application number: TW110133138A
Authority: TW
Inventors: 徐大正; 鍾崇仁; 馮天璟; 林峻毅; 郭威慶; 葉威村; 周成澤
Original assignee: 晶成半導體股份有限公司
Filing date: 2021-09-07
Publication date: 2024-06-11

Abstract

An acoustic wave device includes: a supporting substrate; a seed layer formed above the supporting substrate, wherein a cavity is between the supporting substrate and the seed layer; a first electrode formed above the seed layer; a piezoelectric layer formed above the first electrode; a second electrode formed above the piezoelectric layer; and a first protective layer formed above the second electrode, formed between the seed layer and the second electrode, or formed below the seed layer. The first protective layer is formed by atomic layer deposition.

Description

聲波元件 Acoustic components

本發明是關於一種聲波元件及其製造方法，特別是關於一種具有空腔的聲波元件及其製造方法。 The present invention relates to an acoustic wave element and a manufacturing method thereof, in particular to an acoustic wave element having a cavity and a manufacturing method thereof.

無線頻率通訊裝置(例如智慧型手機)為了能夠在各種無線電頻率與頻段正常運行，需要仰賴聲波濾波器濾除其頻率範圍以外鄰近頻段的信號。為了滿足日益複雜的通訊裝置之要求，有必要針對不同的通信通道以及通訊裝置而使用具有不同型態與組成的聲波元件之濾波器，以在不同頻寬範圍進行調諧。 In order for wireless communication devices (such as smart phones) to operate normally in various radio frequencies and frequency bands, they need to rely on acoustic filters to filter out signals from adjacent frequency bands outside their frequency range. In order to meet the requirements of increasingly complex communication devices, it is necessary to use filters with acoustic wave elements of different types and compositions for different communication channels and communication devices to tune in different bandwidth ranges.

隨著通訊裝置不斷朝輕、薄、短小及時尚化方向發展，且頻率資源越來越擁擠，具有高性能(例如，高Q值及/或高壓電耦合率)聲波元件的濾波器顯得更為重要。儘管現有的聲波元件已大致符合濾波器及各種通訊裝置之需求，但並非在各方面皆令人滿意。 As communication devices continue to develop in the direction of being lighter, thinner, shorter and more fashionable, and frequency resources are becoming increasingly crowded, filters with high-performance (e.g., high Q value and/or high piezoelectric coupling ratio) acoustic wave components are becoming more important. Although existing acoustic wave components have generally met the requirements of filters and various communication devices, they are not satisfactory in all aspects.

本發明實施例提供一種聲波元件。聲波元件包括：支撐基板；形成於支撐基板之上的種子層，其中支撐基板與種子層間具有空腔；形成於種子層之上的第一電極；形成於第一電極之上的壓電層；形成於壓電層之上的第二電極；以及形成於第二電極之上、或形成於種子層與第二電極之間、或形成於種子層之下的第一保護層。第一保護層係利用原子層沉積法所形成。 The present invention provides an acoustic wave element. The acoustic wave element includes: a supporting substrate; a seed layer formed on the supporting substrate, wherein a cavity is formed between the supporting substrate and the seed layer; a first electrode formed on the seed layer; a piezoelectric layer formed on the first electrode; a second electrode formed on the piezoelectric layer; and a first protective layer formed on the second electrode, or formed between the seed layer and the second electrode, or formed under the seed layer. The first protective layer is formed by atomic layer deposition.

100,200,300,400,500,600,700,800:聲波元件 100,200,300,400,500,600,700,800: Acoustic wave components

102:支撐基板 102: Supporting substrate

104:犧牲層 104: Sacrifice layer

105:空腔 105: Cavity

106:支撐層 106: Support layer

108:種子層 108: Seed layer

110:第一電極 110: First electrode

111:金屬層 111:Metal layer

112:壓電層 112: Piezoelectric layer

114:第二電極 114: Second electrode

115:縫隙 115: Gap

116,117,118,120,122,124:保護層 116,117,118,120,122,124: Protective layer

130:主動區 130: Active zone

140:減縮部 140: Reduction section

145:缺口 145: Gap

A-A’,B-B’:剖線 A-A’, B-B’: section line

R1:元件區 R1: Component area

R2:周邊區 R2: Peripheral area

θ1:第一夾角 θ1: first angle

θ2:第二夾角 θ2: Second angle

以下將配合所附圖式詳述本發明實施例。應注意的是，依據在業界的標準做法，各種特徵並未按照比例繪製且僅用以說明例示。事實上，可任意地放大或縮小元件的尺寸，以清楚地表現出本發明實施例的特徵。 The following will be described in detail with the accompanying drawings. It should be noted that, according to standard practice in the industry, various features are not drawn to scale and are only used for illustration. In fact, the size of the components can be arbitrarily enlarged or reduced to clearly show the features of the embodiments of the present invention.

第1A至1J圖是根據一些實施例，繪示出在製造聲波元件的過程中各個中間階段的剖面示意圖。 Figures 1A to 1J are schematic cross-sectional views of various intermediate stages in the process of manufacturing an acoustic wave element according to some embodiments.

第2A至2D圖與3A至3D圖是根據其他實施例，繪示出在製造具有不同保護層配置的聲波元件的過程中各個中間階段的剖面示意圖。 Figures 2A to 2D and 3A to 3D are schematic cross-sectional views of various intermediate stages in the process of manufacturing an acoustic wave element with different protective layer configurations according to other embodiments.

第4至6圖是根據各種實施例的聲波元件剖面圖。 Figures 4 to 6 are cross-sectional views of acoustic wave elements according to various embodiments.

第7A至7C圖是根據其他實施例，繪示出在製造具有環狀結構保護層的聲波元件的過程中各個中間階段的剖面示意圖。 Figures 7A to 7C are schematic cross-sectional views of various intermediate stages in the process of manufacturing an acoustic wave element having a ring-shaped structural protective layer according to other embodiments.

第7D至7F圖是根據各種實施例，繪示出具有環狀結構的聲波元件上視示意圖。 Figures 7D to 7F are schematic top views of an acoustic wave element having a ring structure according to various embodiments.

第8圖是根據其他實施例，繪示出具有元件區及周邊區的聲波元件上視示意圖。 FIG. 8 is a schematic top view of an acoustic wave element having an element region and a peripheral region according to other embodiments.

第9圖是根據其他實施例，繪示出具有元件區及周邊區的聲波元件剖面示意圖。 FIG. 9 is a schematic cross-sectional view of an acoustic wave element having an element region and a peripheral region according to other embodiments.

以下說明本發明實施例之聲波元件及其形成方法。然而，應能理解本發明實施例提供許多合適的發明概念而可實施於廣泛的各種特定背景。所揭示的特定實施例僅用於說明以特定方法製作及使用本發明，而並非用以侷限本發明的範圍。再者，在本發明實施例之圖式及說明內容中係使用相同的標號來表示相同或相似的部件。 The following describes the acoustic wave element and its forming method of the embodiment of the present invention. However, it should be understood that the embodiment of the present invention provides many suitable invention concepts and can be implemented in a wide variety of specific backgrounds. The specific embodiment disclosed is only used to illustrate the manufacture and use of the present invention in a specific method, and is not used to limit the scope of the present invention. Furthermore, the same reference numerals are used in the drawings and descriptions of the embodiments of the present invention to represent the same or similar components.

第1A至1J圖是根據一些實施例，繪示出在製造聲波元件100的過程中各個中間階段的剖面示意圖。參照第1A圖，提供支撐基板102，且於支撐基板102上形成犧牲層104。犧牲層104將於後續製程時被移除以形成聲波元件100中的空腔。在一些實施例中，支撐基板102的材料可包括半導體材料或絕緣材料，半導體材料可包括矽、碳化矽、氮化鋁、氮化鎵、氮化鋁鎵等或前述之組合，絕緣材料可包括藍寶石、玻璃、聚醯亞胺(polyimide,PI)等或前述之組合。 Figures 1A to 1J are cross-sectional schematic diagrams of various intermediate stages in the process of manufacturing the acoustic wave element 100 according to some embodiments. Referring to Figure 1A, a support substrate 102 is provided, and a sacrificial layer 104 is formed on the support substrate 102. The sacrificial layer 104 will be removed in a subsequent process to form a cavity in the acoustic wave element 100. In some embodiments, the material of the support substrate 102 may include a semiconductor material or an insulating material, and the semiconductor material may include silicon, silicon carbide, aluminum nitride, gallium nitride, aluminum gallium nitride, etc., or a combination thereof, and the insulating material may include sapphire, glass, polyimide (PI), etc., or a combination thereof.

在一些實施例中，犧牲層104的材料可包括無機材料、有機材料或前述之組合。例如，無機材料可包括四乙氧基矽烷 (tetraethoxysilane,TEOS)、多晶矽(polysilicon)非晶矽(amorphous silicon,a-Si)、二氧化矽、硼磷矽酸鹽玻璃(borophosphosilicate glass,BPSG)、磷矽酸鹽玻璃(phosphosilicate glass,PSG)等或前述之組合。例如，有機材料可包括光阻或聚醯亞胺等有機高分子材料。可利用如化學氣相沉積(chemical vapor deposition,CVD)製程、原子層沉積(atomic layer deposition,ALD)製程、物理氣相沉積(physical vapor deposition,PVD)製程、旋轉塗佈(spin-on coating)製程、其他適當的製程或前述之組合沉積犧牲層104的材料。接著，可利用適當的製程如光學微影製程及/或蝕刻製程或其他替代方式圖案化犧牲層104的材料，以於支撐基板102上預定的位置或區域形成犧牲層104。 In some embodiments, the material of the sacrificial layer 104 may include an inorganic material, an organic material, or a combination thereof. For example, the inorganic material may include tetraethoxysilane (TEOS), polysilicon, amorphous silicon (a-Si), silicon dioxide, borophosphosilicate glass (BPSG), phosphosilicate glass (PSG), or a combination thereof. For example, the organic material may include organic polymer materials such as photoresist or polyimide. The material of the sacrificial layer 104 may be deposited by a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, a physical vapor deposition (PVD) process, a spin-on coating process, other appropriate processes, or a combination thereof. Then, the material of the sacrificial layer 104 may be patterned by an appropriate process such as a photolithography process and/or an etching process or other alternative methods to form the sacrificial layer 104 at a predetermined position or region on the supporting substrate 102.

接著，如第1B圖所示，在一些實施例中，可於支撐基板102上形成支撐層106，且支撐層106的頂表面與犧牲層104的頂表面可相互齊平。在後續移除犧牲層104的步驟之後，支撐層106可作為聲波元件100的支撐結構。詳細而言，可先於支撐基板102與犧牲層104上沉積支撐層106的材料，接著進行如化學機械研磨(chemical mechanical polishing,CMP)的平坦化製程移除犧牲層104上的支撐層材料，使得支撐層106的頂表面與犧牲層104的頂表面相互齊平。支撐層106的材料可選自任何與犧牲層104相比具有較高蝕刻抗性(etching resistance)的合適材料，例如單晶矽、多晶矽、非晶矽、二氧化矽等或前述之組合。在一些實施例中，犧牲層104的材料為二氧化矽或磷矽酸鹽玻璃時，支撐層106的材料可選用單晶矽。 Next, as shown in FIG. 1B , in some embodiments, a supporting layer 106 may be formed on the supporting substrate 102, and the top surface of the supporting layer 106 may be flush with the top surface of the sacrificial layer 104. After the subsequent step of removing the sacrificial layer 104, the supporting layer 106 may serve as a supporting structure of the acoustic wave device 100. In detail, the material of the support layer 106 may be deposited on the support substrate 102 and the sacrificial layer 104, and then a planarization process such as chemical mechanical polishing (CMP) is performed to remove the support layer material on the sacrificial layer 104, so that the top surface of the support layer 106 is flush with the top surface of the sacrificial layer 104. The material of the support layer 106 may be selected from any suitable material having a higher etching resistance than the sacrificial layer 104, such as single crystal silicon, polycrystalline silicon, amorphous silicon, silicon dioxide, etc., or a combination thereof. In some embodiments, when the material of the sacrificial layer 104 is silicon dioxide or phosphosilicate glass, the material of the supporting layer 106 can be single crystal silicon.

然而，根據本發明的其他實施例，也可不額外形成支撐層106。詳細而言，可從支撐基板102的頂表面直接凹蝕支撐基板102以形成用於填充犧牲層材料的凹口，而支撐基板102於凹口周圍未被蝕刻去除的部分則作為聲波元件100的支撐結構。接著，於凹口中沉積犧牲層的材料，然後可進行如化學機械研磨的平坦化製程移除過多的犧牲層材料，以露出支撐基板102的頂表面。此外，進行平坦化製程之後，支撐基板102的頂表面可與犧牲層的頂表面齊平。在不額外形成支撐層106的這些實施例中，支撐基板102的材料相較於犧牲層的材料具有較高的蝕刻抗性，使得在後續移除犧牲層材料的步驟中不對支撐基板102造成顯著的蝕刻。 However, according to other embodiments of the present invention, the supporting layer 106 may not be additionally formed. In detail, the supporting substrate 102 may be directly etched from the top surface of the supporting substrate 102 to form a recess for filling the sacrificial layer material, and the portion of the supporting substrate 102 that is not etched away around the recess serves as a supporting structure for the acoustic wave element 100. Then, the sacrificial layer material is deposited in the recess, and then a planarization process such as chemical mechanical polishing may be performed to remove excess sacrificial layer material to expose the top surface of the supporting substrate 102. In addition, after the planarization process, the top surface of the supporting substrate 102 may be flush with the top surface of the sacrificial layer. In these embodiments where the support layer 106 is not additionally formed, the material of the support substrate 102 has a higher etching resistance than the material of the sacrificial layer, so that the support substrate 102 is not significantly etched in the subsequent step of removing the sacrificial layer material.

接著，參照第1C圖，於犧牲層104上形成種子層108。在形成有支撐層106的實施例中，種子層108形成於犧牲層104與支撐層106上。在形成聲波元件100的第一電極之前，設置種子層108有助於提升其上形成的第一電極的晶相品質，也能提升第一電極上壓電層的晶相品質。此外，種子層108也於後續移除犧牲層104的步驟中作為聲波元件100第一電極的保護層，以避免因過度蝕刻侵蝕第一電極而造成聲波元件的性能受損。在一些實施例中，種子層108的材料可搭配壓電層的材料調整，例如可包括半導體材料、陶瓷材料或薄膜材料，半導體材料可包括氮化鋁、或氮化鈧鋁(Sc_xAl_1-xN，其中x小於1且大於0)，陶瓷材料可包括鋯鈦酸鉛 (PZT，亦可稱為壓電陶瓷)，薄膜材料可包括氧化鋅。。在一些實施例中，可利用物理氣相沉積、原子層沉積、金屬有機化學氣相沉積(metal organic CVD,MOCVD)、其他合適的沉積技術或前述之組合來沉積種子層108。在一些實施例中，種子層108可利用濺射沉積(sputtering deposition)來形成，厚度可介於約30奈米(nm)至80奈米(nm)之間。 Next, referring to FIG. 1C , a seed layer 108 is formed on the sacrificial layer 104. In the embodiment in which the support layer 106 is formed, the seed layer 108 is formed on the sacrificial layer 104 and the support layer 106. Before forming the first electrode of the acoustic wave element 100, providing the seed layer 108 helps to improve the crystal quality of the first electrode formed thereon, and also improves the crystal quality of the piezoelectric layer on the first electrode. In addition, the seed layer 108 also serves as a protective layer for the first electrode of the acoustic wave element 100 in the subsequent step of removing the sacrificial layer 104, so as to prevent the performance of the acoustic wave element from being damaged due to excessive etching of the first electrode. In some embodiments, the material of the seed layer 108 can be adjusted with the material of the piezoelectric layer, for example, it can include semiconductor materials, ceramic materials or thin film materials. The semiconductor material can include aluminum nitride or aluminum nitride (Sc _x Al _1-x N, where x is less than 1 and greater than 0), the ceramic material can include lead zirconium titanate (PZT, also known as piezoelectric ceramics), and the thin film material can include zinc oxide. In some embodiments, the seed layer 108 can be deposited by physical vapor deposition, atomic layer deposition, metal organic chemical vapor deposition (MOCVD), other suitable deposition techniques or a combination thereof. In some embodiments, the seed layer 108 may be formed by sputtering deposition and may have a thickness ranging from about 30 nm to about 80 nm.

接著，參照第1D圖，於種子層108上形成第一電極110。詳細而言，在一些實施例中，可於種子層108上沉積第一電極110的材料並接著圖案化第一電極110，以於預定的區域形成具有特定圖案形狀的第一電極110且露出種子層108未被圖案化製程所使用的光阻保護的部分。於一實施例中，第一電極110於聲波元件100剖面圖中的特定圖案形狀包含梯形形狀或矩形形狀，一般而言，具有梯形形狀或矩形形狀的第一電極110的頂角(即，第一電極110的側壁與頂表面之間的夾角)為一鈍角或一直角。於一實施例中，頂角可在約90度至約165度之間的範圍。在一些特定實施例中，第一電極110可具有約135度至約160度之間的頂角。 Next, referring to FIG. 1D , a first electrode 110 is formed on the seed layer 108. Specifically, in some embodiments, a material of the first electrode 110 may be deposited on the seed layer 108 and then patterned to form the first electrode 110 having a specific pattern shape in a predetermined region and to expose a portion of the seed layer 108 that is not protected by the photoresist used in the patterning process. In one embodiment, the specific pattern shape of the first electrode 110 in the cross-sectional view of the acoustic wave element 100 includes a trapezoidal shape or a rectangular shape. Generally speaking, the top angle of the first electrode 110 having a trapezoidal shape or a rectangular shape (i.e., the angle between the side wall and the top surface of the first electrode 110) is a blunt angle or a right angle. In one embodiment, the top angle may be in a range between about 90 degrees and about 165 degrees. In some specific embodiments, the first electrode 110 may have a top angle between about 135 degrees and about 160 degrees.

第一電極110的材料可包括鉬(Mo)、鋁(Al)、鈦(Ti)、鈦鎢合金(TiW)、銣(Ru)、銀(Ag)、銅(Cu)、金(Au)、鉑(Pt)或前述之組合，且可利用脈衝雷射沉積(pulsed laser deposition,PLD)、濺射沉積(sputtering deposition)、電子束蒸鍍(e-beam evaporation)、其他合適的沉積技術或前述之組合來沉積第一電極110的材料。在一些實施例中，第一電極110 的厚度可介於約0.01μm至約5μm之間。在一些實施例中，第一電極110的厚度可介於約0.1μm至約0.4μm之間。 The material of the first electrode 110 may include molybdenum (Mo), aluminum (Al), titanium (Ti), titanium-tungsten alloy (TiW), ruthenium (Ru), silver (Ag), copper (Cu), gold (Au), platinum (Pt), or a combination thereof, and the material of the first electrode 110 may be deposited using pulsed laser deposition (PLD), sputtering deposition, electron beam evaporation (e-beam evaporation), other suitable deposition techniques, or a combination thereof. In some embodiments, the thickness of the first electrode 110 may be between about 0.01 μm and about 5 μm. In some embodiments, the thickness of the first electrode 110 may be between about 0.1 μm and about 0.4 μm.

接著，參照第1E圖，於第一電極110上形成壓電層112。如第1E圖所示，在一些實施例中，壓電層112可覆蓋第一電極110的頂表面與側壁，且更延伸至種子層108上。在一些實施例中，壓電層112的壓電材料可包括半導體材料、陶瓷材料或薄膜材料，半導體材料可包括氮化鋁或氮化鈧鋁(Sc_xAl_1-xN，其中x小於1且大於0)，陶瓷材料可包括鋯鈦酸鉛，薄膜材料可包括氧化鋅。在一些特定實施例中，壓電層112的壓電材料可包括Sc_xAl_1-xN，其中x小於1且大於或等於0(即，壓電材料可為氮化鋁或氮化鈧鋁)。可利用脈衝雷射沉積、濺射沉積、電子束蒸鍍等或前述之組合來沉積壓電層112。在一些實施例中，壓電層112的厚度可介於約0.05μm至約10μm之間。在一些實施例中，壓電層112的厚度可介於約0.4μm至約1.5μm之間。 Next, referring to FIG. 1E , a piezoelectric layer 112 is formed on the first electrode 110. As shown in FIG. 1E , in some embodiments, the piezoelectric layer 112 may cover the top surface and sidewalls of the first electrode 110, and further extend onto the seed layer 108. In some embodiments, the piezoelectric material of the piezoelectric layer 112 may include a semiconductor material, a ceramic material, or a thin film material, the semiconductor material may include aluminum nitride or aluminum nitride (Sc _x Al _1-x N, wherein x is less than 1 and greater than 0), the ceramic material may include lead zirconate titanate, and the thin film material may include zinc oxide. In some specific embodiments, the piezoelectric material of the piezoelectric layer 112 may include Sc _x Al _1-x N, where x is less than 1 and greater than or equal to 0 (i.e., the piezoelectric material may be aluminum nitride or carbendazim). The piezoelectric layer 112 may be deposited using pulsed laser deposition, sputtering deposition, electron beam evaporation, or the like, or a combination thereof. In some embodiments, the thickness of the piezoelectric layer 112 may be between about 0.05 μm and about 10 μm. In some embodiments, the thickness of the piezoelectric layer 112 may be between about 0.4 μm and about 1.5 μm.

接著，如第1F圖所示，於壓電層112上形成第二電極114。形成第二電極114所使用的材料與製程可與第一電極110的相似或相同，而此不再重複說明。在一些實施例中，第二電極114的厚度可介於約0.01μm至約5μm m之間。在一些實施例中，第二電極114的厚度可介於約0.1μm至約0.4μm之間。根據本發明的一些實施例，如第1G圖所示，由於第一電極110形成具有鈍角或甚至直角的頂角，導致利用沉積製程於第一電極110上形成的膜層可能會在第一電極110頂角向外延伸的方向產生縫隙115。縫隙115可能會延伸穿過第一電極110上的各層至第一電極110，但也可能沒有完全延伸穿過各個膜層至第一電極110，例如縫隙115可能只延伸至部份的壓電層112或部份的第二電極114中，但未穿過壓電層112或第二電極114，即縫隙115的底部位於壓電層112或第二電極114中。 Next, as shown in FIG. 1F , a second electrode 114 is formed on the piezoelectric layer 112. The materials and processes used to form the second electrode 114 may be similar or the same as those of the first electrode 110 , and will not be repeated here. In some embodiments, the thickness of the second electrode 114 may be between about 0.01 μm and about 5 μm m. In some embodiments, the thickness of the second electrode 114 may be between about 0.1 μm and about 0.4 μm. According to some embodiments of the present invention, as shown in FIG. 1G , since the first electrode 110 is formed with a blunt or even right-angled top corner, the film layer formed on the first electrode 110 using a deposition process may generate a gap 115 in the direction in which the top corner of the first electrode 110 extends outward. The gap 115 may extend through each layer on the first electrode 110 to the first electrode 110, but may not completely extend through each film layer to the first electrode 110. For example, the gap 115 may only extend to part of the piezoelectric layer 112 or part of the second electrode 114, but not through the piezoelectric layer 112 or the second electrode 114, that is, the bottom of the gap 115 is located in the piezoelectric layer 112 or the second electrode 114.

在後續移除犧牲層104的蝕刻製程中，若聲波元件100之中存在著縫隙115，蝕刻製程所使用的蝕刻劑可能會沿著縫隙115進入聲波元件100並侵蝕聲波元件100中的各個膜層，進而造成聲波元件100功能失效。應注意的是，為了簡化圖式，後續圖式有時會省略各個膜層中的縫隙115。然而，為了清楚起見，下文將根據本發明不同的實施例，詳細地說明縫隙形成的位置。 In the subsequent etching process of removing the sacrificial layer 104, if there is a gap 115 in the acoustic wave element 100, the etchant used in the etching process may enter the acoustic wave element 100 along the gap 115 and erode each film layer in the acoustic wave element 100, thereby causing the acoustic wave element 100 to fail in function. It should be noted that in order to simplify the drawings, the gaps 115 in each film layer are sometimes omitted in the subsequent drawings. However, for the sake of clarity, the location where the gap is formed will be described in detail below according to different embodiments of the present invention.

接著，參照第1H圖，在一些實施例中，可利用具有高順應性沉積法，例如原子層沉積法於第二電極114上形成保護層116，且保護層116可延伸填入第1G圖中所示的縫隙115(第二電極與壓電層中的縫隙)。如前文所討論，即便保護層116下方的膜層具有縫隙，具有高順應性的原子層沉積法仍可使得保護層116填補下方膜層中的縫隙，而不會於保護層116中持續形成擴大的縫隙。如此一來，可避免保護層116上形成的膜層(若有的話)產生縫隙，也防止後續移除犧牲層104的蝕刻製程中所使用的蝕刻劑侵入聲波元件100而侵蝕聲波元件100的各個膜層。在一些實施例中，保護層116的材料可包括金屬氧化物或金屬氮化物。例如，金屬氧化物可包括氧化鋁、氧化鉿、氧化鋯、氧化鉭、氧化鈦或前述之組合。例如，金屬氮化物可包括氮化鋁、氮化鈦、氮化鋯、或氮化鉻。在一些實施例中，若移除犧牲層104的蝕刻製程中所使用的蝕刻劑為氟化氫氣體，保護層116的材料可選用具有較高蝕刻抗性的材料，例如氧化鋁。在一些實施例中，保護層116的厚度可介於約30nm至70nm之間的範圍，例如約為50nm。此外，利用原子層沉積法所沉積的保護層116也具有高度的緻密性，使保護層116可具有較高的薄膜密度。根據一些實施例，保護層116的材料選用三氧化二鋁(Al₂O₃)，以原子層沉積法形成的薄膜，在以X光反射技術(X-ray reflectivity,XRR)所測量的薄膜密度可介於約3.2g/cm³至約3.76g/cm³之間，例如約為3.32g/cm³。 Next, referring to FIG. 1H , in some embodiments, a highly compliant deposition method, such as atomic layer deposition, may be used to form a protective layer 116 on the second electrode 114, and the protective layer 116 may extend to fill the gap 115 (the gap between the second electrode and the piezoelectric layer) shown in FIG. 1G . As discussed above, even if the film layer below the protective layer 116 has a gap, the highly compliant atomic layer deposition method can still allow the protective layer 116 to fill the gap in the film layer below without continuously forming an enlarged gap in the protective layer 116 . In this way, it is possible to avoid the formation of cracks in the film layer (if any) formed on the protective layer 116, and to prevent the etchant used in the subsequent etching process for removing the sacrificial layer 104 from invading the acoustic wave device 100 and corroding each film layer of the acoustic wave device 100. In some embodiments, the material of the protective layer 116 may include metal oxide or metal nitride. For example, the metal oxide may include aluminum oxide, bismuth oxide, zirconium oxide, tantalum oxide, titanium oxide, or a combination thereof. For example, the metal nitride may include aluminum nitride, titanium nitride, zirconium nitride, or chromium nitride. In some embodiments, if the etchant used in the etching process for removing the sacrificial layer 104 is hydrogen fluoride gas, the material of the protective layer 116 can be selected to have a material with high etching resistance, such as aluminum oxide. In some embodiments, the thickness of the protective layer 116 can be in the range of about 30nm to 70nm, such as about 50nm. In addition, the protective layer 116 deposited by atomic layer deposition also has a high degree of density, so that the protective layer 116 can have a higher film density. According to some embodiments, the material of the protection layer 116 is aluminum oxide (Al ₂ O ₃ ), and the film density measured by X-ray reflectivity (XRR) can be between about 3.2 g/cm ³ and about 3.76 g/cm ³ , for example, about 3.32 g/cm ³ .

參照第1I圖，在一些實施例中，可於保護層116上形成保護層118。在一些實施例中，保護層118的材料可包括高聲阻抗材料，例如氮化物系列材料，例如SiN_x、AlN、Sc_xAl_1-xN(x小於1且大於或等於0)或前述之組合。保護層116與形成於保護層116上且包含氮化物系列材料的保護層118可作為雙層保護層，其中保護層116可用於填補下方膜層中的縫隙，且包含氮化物系列材料的保護層118可用於提供良好的化學保護。在聲波元件100最終的處理步驟中，可根據設計需求，視需要地調整保護層118的厚度以對聲波元件100進行頻率調控，進而使所製得的聲波元件100達到所欲的作用頻率範圍。可利用脈衝雷射沉積、濺射沉積、電子束蒸鍍等或前述之組合來沉積保護層118。在一些實施例中，保護層118的厚度可介於約30nm至約70nm之間。 1I, in some embodiments, a protective layer 118 may be formed on the protective layer 116. In some embodiments, the material of the protective layer 118 may include a high acoustic impedance material, such as a nitride series material, such as _SiNx , AlN, _ScxAl1 _-xN (x is less than 1 and greater than or equal to 0), or a combination thereof. The protective layer 116 and the protective layer 118 formed on the protective layer 116 and including the nitride series material may serve as a double-layer protective layer, wherein the protective layer 116 may be used to fill the gap in the underlying film layer, and the protective layer 118 including the nitride series material may be used to provide good chemical protection. In the final processing step of the acoustic wave device 100, the thickness of the protective layer 118 may be adjusted as needed according to design requirements to perform frequency control on the acoustic wave device 100, thereby making the acoustic wave device 100 reach the desired operating frequency range. The protective layer 118 may be deposited by pulsed laser deposition, sputtering deposition, electron beam evaporation, etc., or a combination thereof. In some embodiments, the thickness of the protective layer 118 may be between about 30 nm and about 70 nm.

接著，參照第1J圖，移除犧牲層104。可利用選擇性的蝕刻製程移除犧牲層104，以於支撐基板102與種子層108之間形成空腔105。在一些實施例中，可於聲波元件100中自其表面形成至少一通孔(未繪示)以將犧牲層104從聲波元件100露出，進而使蝕刻製程的蝕刻劑得以進入聲波元件100之中而移除犧牲層104。 Next, referring to FIG. 1J, the sacrificial layer 104 is removed. The sacrificial layer 104 may be removed by a selective etching process to form a cavity 105 between the supporting substrate 102 and the seed layer 108. In some embodiments, at least one through hole (not shown) may be formed in the acoustic wave element 100 from its surface to expose the sacrificial layer 104 from the acoustic wave element 100, thereby allowing the etchant of the etching process to enter the acoustic wave element 100 and remove the sacrificial layer 104.

移除犧牲層104的蝕刻製程可包括濕式蝕刻、氣相蝕刻(vapor etching)以及/或其他合適的蝕刻製程。例如，濕式蝕刻製程可採用酸性溶液或鹼性溶液、或其他合適的濕式蝕刻化學物質來進行。酸性溶液可包括氫氟酸、磷酸、硝酸、醋酸等或前述之組合的溶液；鹼性溶液可包括含有氫氧化鉀、氨、過氧化氫等或前述之組合的溶液。例如，氣相蝕刻製程可採用氟化氫氣相蝕刻(HF vapor etching)或二氟化氙氣相蝕刻(XeF₂ vapor etching)。在一些特定實施例中，可使用氣相氟化氫蝕刻製程來移除犧牲層104。移除犧牲層104之後，如第1J圖所示，支撐基板102與種子層108之間具有空腔105。 The etching process for removing the sacrificial layer 104 may include wet etching, vapor etching, and/or other suitable etching processes. For example, the wet etching process may be performed using an acidic solution or an alkaline solution, or other suitable wet etching chemicals. The acidic solution may include a solution containing hydrofluoric acid, phosphoric acid, nitric acid, acetic acid, or a combination thereof; the alkaline solution may include a solution containing potassium hydroxide, ammonia, hydrogen peroxide, or a combination thereof. For example, the vapor etching process may include HF vapor etching or XeF ₂ vapor etching. In some specific embodiments, a vapor phase HF vapor etching process may be used to remove the sacrificial layer 104. After the sacrificial layer 104 is removed, as shown in FIG. 1J , a cavity 105 is formed between the supporting substrate 102 and the seed layer 108 .

根據第1A至1J圖所示的實施例，利用原子層沉積所形成的保護層可延伸填入第一電極之上膜層中的縫隙，防止在移除犧牲層的蝕刻製程時蝕刻劑透過縫隙侵入聲波元件之中而導致聲波元件受損。此外，原子層沉積所形成的保護層可與其上形成用於頻率調控的保護層形成雙層保護層，可在移除犧牲層的蝕刻製程時提供良好的化學保護，進而降低聲波元件功能失效的可能性。 According to the embodiments shown in Figures 1A to 1J, the protective layer formed by atomic layer deposition can be extended to fill the gap in the film layer above the first electrode to prevent the etchant from penetrating into the acoustic wave element through the gap during the etching process of removing the sacrificial layer and causing damage to the acoustic wave element. In addition, the protective layer formed by atomic layer deposition can form a double-layer protective layer with the protective layer formed thereon for frequency regulation, which can provide good chemical protection during the etching process of removing the sacrificial layer, thereby reducing the possibility of functional failure of the acoustic wave element.

第2A至2D圖是根據其他實施例，繪示出在製造具有不同保護層配置的聲波元件200的過程中各個中間階段的剖面示意圖。參照第2A圖，第2A圖中的聲波元件200與第1I圖中的聲波元件100相似，但聲波元件200的保護層118形成於第二電極114與保護層116之間。聲波元件200之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。在第2A圖所示的實施例中，如前文所述，第二電極114可具有如第1G圖所示的縫隙115，而直接形成於第二電極114上的保護層118可能也會具有縫隙。因此，利用原子層沉積法形成於保護層118上的保護層116可更延伸填入保護層118的縫隙中。 FIGS. 2A to 2D are cross-sectional schematic diagrams of various intermediate stages in the process of manufacturing an acoustic wave element 200 having different protective layer configurations according to other embodiments. Referring to FIG. 2A, the acoustic wave element 200 in FIG. 2A is similar to the acoustic wave element 100 in FIG. 1I, but the protective layer 118 of the acoustic wave element 200 is formed between the second electrode 114 and the protective layer 116. Some of the processes and structures of the acoustic wave element 200 are similar to those of the acoustic wave element 100. For similar processes and structures, please refer to the description and drawings of the acoustic wave element 100, and no further description will be given. The differences will be described in detail later. In the embodiment shown in FIG. 2A, as described above, the second electrode 114 may have a gap 115 as shown in FIG. 1G, and the protective layer 118 directly formed on the second electrode 114 may also have a gap. Therefore, the protective layer 116 formed on the protective layer 118 by atomic layer deposition can be further extended to fill the gap of the protective layer 118.

接著，如第2B圖所示，類似第2A圖的聲波元件200，可於保護層116上更形成保護層120。在一些實施例中，保護層120的材料可包括Sc_yAl_1-yN，其中y小於1且大於或等於0。可利用脈衝雷射沉積、濺射沉積、電子束蒸鍍等或前述之組合來沉積保護層120。保護層120與下方的保護層116可作為雙層保護層，其中保護層116不僅可延伸填入沉積製程中所形成的縫隙，且包括氮化鋁系列材料的保護層120也可為下方膜層提供良好的化學保護。 Next, as shown in FIG. 2B , a protective layer 120 may be formed on the protective layer 116 similar to the acoustic wave device 200 of FIG. 2A . In some embodiments, the material of the protective layer 120 may include _ScyAl1 _-yN , wherein y is less than 1 and greater than or equal to 0. The protective layer 120 may be deposited by pulsed laser deposition, sputtering deposition, electron beam evaporation, or a combination thereof. The protective layer 120 and the protective layer 116 below may serve as a double-layer protective layer, wherein the protective layer 116 may not only extend to fill the gap formed in the deposition process, but the protective layer 120 including the aluminum nitride series material may also provide good chemical protection for the film layer below.

接著，參照第2C圖，移除犧牲層104以於種子層108與支撐基板102之間形成空腔105。形成空腔105之後，接著，如第2D圖所示，可進一步移除保護層116與120以露出用以調控頻率的保護層118。可利用合適的蝕刻製程如乾式蝕刻、濕式蝕刻或前述之組合移除保護層116與120。在一些實施例中，移除保護層116與120之後，保護層116延伸填入前述縫隙中的部分可保留而沒有被移除。 Next, referring to FIG. 2C , the sacrificial layer 104 is removed to form a cavity 105 between the seed layer 108 and the supporting substrate 102 . After the cavity 105 is formed, the protective layers 116 and 120 may be further removed to expose the protective layer 118 for frequency modulation as shown in FIG. 2D . The protective layers 116 and 120 may be removed by a suitable etching process such as dry etching, wet etching, or a combination thereof. In some embodiments, after removing the protective layers 116 and 120, the portion of the protective layer 116 extending into the aforementioned gap may be retained without being removed.

第3A至3D圖是根據其他實施例，繪示出在製造具有不同保護層配置的聲波元件300的過程中各個中間階段的剖面示意圖。參照第3A圖，第3A圖中的聲波元件300與第1I圖中的聲波元件100相似，但聲波元件300的保護層116形成於壓電層112與第二電極114之間。聲波元件300之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。在第3A圖所示的實施例中，如前文所述，由於壓電層112可具有縫隙，因此先利用原子層沉積法形成的保護層116可延伸填入壓電層112的縫隙。再者，由於保護層116已填充壓電層112的縫隙，保護層116之上形成的第二電極114、保護層118及其他膜層可能不會產生縫隙。 FIGS. 3A to 3D are cross-sectional schematic diagrams of various intermediate stages in the process of manufacturing an acoustic wave element 300 with different protective layer configurations according to other embodiments. Referring to FIG. 3A , the acoustic wave element 300 in FIG. 3A is similar to the acoustic wave element 100 in FIG. 1I , but the protective layer 116 of the acoustic wave element 300 is formed between the piezoelectric layer 112 and the second electrode 114. Some of the processes and structures of the acoustic wave element 300 are similar to those of the acoustic wave element 100 . For similar processes and structures, please refer to the description and drawings of the acoustic wave element 100 . No further description will be given. The differences will be described in detail later. In the embodiment shown in FIG. 3A, as described above, since the piezoelectric layer 112 may have gaps, the protective layer 116 formed by atomic layer deposition can be extended to fill the gaps of the piezoelectric layer 112. Furthermore, since the protective layer 116 has filled the gaps of the piezoelectric layer 112, the second electrode 114, the protective layer 118 and other film layers formed on the protective layer 116 may not generate gaps.

接著，參照第3B圖，在一些實施例中，可於保護層118上形成保護層122，且於保護層122上形成保護層124。在這些實施例中，保護層122類似保護層116，可包括利用原子層沉積法形成的金屬氧化物或金屬氮化物。例如，金屬氧化物可包括氧化鋁、氧化鉿、氧化鋯、氧化鉭、氧化鈦或前述之組合。例如，金屬氮化物可包括氮化鋁、氮化鈦、氮化鋯、或氮化鉻。保護層124類似保護層118，可包括Sc_zAl_1-zN，其中z小於1且大於或等於0。利用原子層沉積法所沉積的保護層122具有高度的緻密性，使保護層122可具有較高的薄膜密度。因此，根據一些實施例，保護層122的材料選用三氧化二鋁(Al₂O₃)，以原子層沉積法形成的薄膜，在以 X光反射技術所測量的薄膜密度可介於約3.2g/cm³至約3.76g/cm³之間，例如約為3.32g/cm³。此外，在一些實施例中，保護層122的厚度可介於約30nm至約70nm之間，例如約為50nm。在一些實施例中，保護層124的厚度可介於約30nm至約70nm之間。可利用脈衝雷射沉積、濺射沉積、電子束蒸鍍等或前述之組合來沉積保護層124。如第3B圖所示，聲波元件300中，除了具有保護層116可填補第一電極110之上各個膜層中的縫隙，也具有作為雙層保護層的保護層122與124。保護層122與124形成的雙層保護層具有良好的化學保護能力，可避免下方膜層因移除犧牲層104的蝕刻製程而受到損傷，進而防止聲波元件功能失效。 Next, referring to FIG. 3B , in some embodiments, a protective layer 122 may be formed on the protective layer 118, and a protective layer 124 may be formed on the protective layer 122. In these embodiments, the protective layer 122 is similar to the protective layer 116, and may include a metal oxide or a metal nitride formed by atomic layer deposition. For example, the metal oxide may include aluminum oxide, tantalum oxide, zirconium oxide, tantalum oxide, titanium oxide, or a combination thereof. For example, the metal nitride may include aluminum nitride, titanium nitride, zirconium nitride, or chromium nitride. The protective layer 124 is similar to the protective layer 118, and may include Sc _z Al _1-z N, where z is less than 1 and greater than or equal to 0. The protective layer 122 deposited by the atomic layer deposition method has a high degree of compactness, so that the protective layer 122 can have a high film density. Therefore, according to some embodiments, the material of the protective layer 122 is selected from aluminum oxide (Al ₂ O ₃ ), and the film density of the film formed by the atomic layer deposition method can be between about 3.2 g/cm ³ and about 3.76 g/cm ³ , for example, about 3.32 g/cm ³ , as measured by X-ray reflection technology. In addition, in some embodiments, the thickness of the protective layer 122 can be between about 30 nm and about 70 nm, for example, about 50 nm. In some embodiments, the thickness of the protective layer 124 can be between about 30 nm and about 70 nm. The protective layer 124 may be deposited by pulsed laser deposition, sputtering deposition, electron beam evaporation, or a combination thereof. As shown in FIG. 3B , the acoustic wave device 300 has not only the protective layer 116 that fills the gaps in the film layers above the first electrode 110, but also the protective layers 122 and 124 that serve as a double protective layer. The double protective layer formed by the protective layers 122 and 124 has good chemical protection capability, which can prevent the film layers below from being damaged by the etching process for removing the sacrificial layer 104, thereby preventing the acoustic wave device from failing.

接著，參照第3C圖，移除犧牲層104以於種子層108與支撐基板102之間形成空腔105。形成空腔105之後，接著，如第3D圖所示，可移除保護層122與124以露出用以調控頻率的保護層118。可利用合適的蝕刻製程如乾式蝕刻、濕式蝕刻或前述之組合移除保護層122與124。 Next, referring to FIG. 3C , the sacrificial layer 104 is removed to form a cavity 105 between the seed layer 108 and the supporting substrate 102 . After the cavity 105 is formed, the protective layers 122 and 124 can be removed to expose the protective layer 118 for frequency modulation as shown in FIG. 3D . The protective layers 122 and 124 can be removed by a suitable etching process such as dry etching, wet etching, or a combination thereof.

第4至6圖是根據各種實施例的聲波元件400、500與600的剖面圖。參照第4圖，第4圖的聲波元件400與第3D圖的聲波元件300相似，但聲波元件400的保護層116形成於第一電極110與壓電層112之間。聲波元件400之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。在第4圖所示的實施例中，可利用原子層沉積於第一電極110上形成順應於第一電極110的保護層 116，以避免第一電極110之上形成的膜層沿著第一電極110頂角向外延伸的方向產生縫隙。此外，在此實施例中，利用原子層沉積形成的保護層116由於具有高緻密性，可為壓電層112的沉積提供較為平坦的表面以改善第一電極110可能具有較高表面粗糙度的問題，進而為聲波元件400整體的結構提供較佳的結構穩定度。 FIGS. 4 to 6 are cross-sectional views of acoustic wave devices 400, 500, and 600 according to various embodiments. Referring to FIG. 4, the acoustic wave device 400 of FIG. 4 is similar to the acoustic wave device 300 of FIG. 3D, but the protective layer 116 of the acoustic wave device 400 is formed between the first electrode 110 and the piezoelectric layer 112. Some processes and structures of the acoustic wave device 400 are similar to those of the acoustic wave device 100. For similar processes and structures, please refer to the description and drawings of the acoustic wave device 100, and no further description will be given. The differences will be described in detail later. In the embodiment shown in FIG. 4, a protective layer 116 conforming to the first electrode 110 can be formed on the first electrode 110 by atomic layer deposition to prevent the film layer formed on the first electrode 110 from generating gaps along the direction of the top corner of the first electrode 110 extending outward. In addition, in this embodiment, the protective layer 116 formed by atomic layer deposition has high density and can provide a relatively flat surface for the deposition of the piezoelectric layer 112 to improve the problem that the first electrode 110 may have a relatively high surface roughness, thereby providing better structural stability for the overall structure of the acoustic wave element 400.

參照第5圖，第5圖的聲波元件500與第3D圖的聲波元件300相似，但聲波元件500的保護層116形成於種子層108與第一電極110之間。聲波元件500之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。在第5圖所示的實施例中，利用原子層沉積形成的保護層116由於具有高緻密性，可為第一電極110的沉積提供較為平坦的表面以改善種子層108可能具有較高表面粗糙度的問題，進而為聲波元件500整體的結構提供較佳的結構穩定度。 Referring to FIG. 5 , the acoustic wave element 500 of FIG. 5 is similar to the acoustic wave element 300 of FIG. 3D , but the protective layer 116 of the acoustic wave element 500 is formed between the seed layer 108 and the first electrode 110. Some processes and structures of the acoustic wave element 500 are similar to those of the acoustic wave element 100 . For similar processes and structures, please refer to the description and drawings of the acoustic wave element 100 . The differences will be described in detail later. In the embodiment shown in FIG. 5 , the protective layer 116 formed by atomic layer deposition has high density and can provide a relatively flat surface for the deposition of the first electrode 110 to improve the problem that the seed layer 108 may have a relatively high surface roughness, thereby providing better structural stability for the overall structure of the acoustic wave element 500.

參照第6圖，第6圖的聲波元件600與第3D圖的聲波元件300相似，但聲波元件600的保護層116形成於支撐基板102與種子層108之間。聲波元件600之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。在一些實施例中，在移除犧牲層的蝕刻製程時，可進一步部分地或完全地移除支撐基板102與種子層108之間的保護層116，特別是犧牲層正上方的保護層116。部分地或完全地移除保護層116可減少保護層116對聲波元件600的聲波共振特性造成的負面影響。 Referring to FIG. 6 , the acoustic wave element 600 of FIG. 6 is similar to the acoustic wave element 300 of FIG. 3D , but the protective layer 116 of the acoustic wave element 600 is formed between the supporting substrate 102 and the seed layer 108. Some processes and structures of the acoustic wave element 600 are similar to those of the acoustic wave element 100. For similar processes and structures, please refer to the description and drawings of the acoustic wave element 100 and will not be described in detail. The differences will be described in detail later. In some embodiments, during the etching process of removing the sacrificial layer, the protective layer 116 between the supporting substrate 102 and the seed layer 108 may be further partially or completely removed, especially the protective layer 116 directly above the sacrificial layer. Partially or completely removing the protective layer 116 can reduce the negative impact of the protective layer 116 on the acoustic resonance characteristics of the acoustic wave element 600.

在第5、6圖所示的實施例中，設置於第一電極110之下的保護層116於移除犧牲層的蝕刻製程時可作為保護層，防止蝕刻製程的蝕刻劑對第一電極110造成損傷，進而避免聲波元件的功能失效。 In the embodiments shown in FIGS. 5 and 6, the protective layer 116 disposed under the first electrode 110 can be used as a protective layer during the etching process for removing the sacrificial layer to prevent the etchant of the etching process from damaging the first electrode 110, thereby avoiding the functional failure of the acoustic wave element.

雖然第4至6圖繪示出製造聲波元件400、500與600的完整結構，但應能理解在製造聲波元件400、500與600的過程中，可於保護層118上形成如第3C圖所示的保護層122與124，以於移除犧牲層的蝕刻製程時提供良好的化學保護，且避免蝕刻製程的蝕刻劑侵蝕下方膜層。再者，在聲波元件400、500與600形成有保護層122與124的實施例中，移除犧牲層之後，可進一步利用合適的蝕刻製程移除保護層122與124以露出用以調控頻率的保護層118。 Although FIGS. 4 to 6 illustrate the complete structure of the acoustic wave elements 400, 500 and 600, it should be understood that in the process of manufacturing the acoustic wave elements 400, 500 and 600, protective layers 122 and 124 as shown in FIG. 3C can be formed on the protective layer 118 to provide good chemical protection during the etching process of removing the sacrificial layer and prevent the etchant of the etching process from corroding the underlying film layer. Furthermore, in the embodiment where the acoustic wave elements 400, 500 and 600 are formed with the protective layers 122 and 124, after removing the sacrificial layer, the protective layers 122 and 124 can be further removed by a suitable etching process to expose the protective layer 118 for frequency modulation.

第7A至7C圖是根據其他實施例，繪示出在製造具有環狀結構保護層117的聲波元件700的過程中各個中間階段的剖面示意圖。聲波元件700之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。參照第7A圖，在一些實施例中，在第1F、1G圖所示的結構上形成保護層117。詳細而言，利用原子層沉積於第二電極114上形成保護材料層(未繪示)，且利用光學微影製程圖案化保護材料層以形成露出一部分的第二電極114的保護層117，例如蝕刻或掀離製程。 FIGS. 7A to 7C are cross-sectional schematic diagrams showing various intermediate stages in the process of manufacturing an acoustic wave element 700 having a ring-shaped structure protection layer 117 according to other embodiments. Some processes and structures of the acoustic wave element 700 are similar to those of the acoustic wave element 100. For similar processes and structures, please refer to the description and drawings of the acoustic wave element 100, and no further description will be given. The differences will be described in detail later. Referring to FIG. 7A, in some embodiments, a protection layer 117 is formed on the structure shown in FIGS. 1F and 1G. In detail, a protective material layer (not shown) is formed on the second electrode 114 by atomic layer deposition, and the protective material layer is patterned by a photolithography process to form a protective layer 117 that exposes a portion of the second electrode 114, such as an etching or lift-off process.

如前文所述，由於第一電極110上的壓電層112與第二電極114可具有如第1G圖所示的縫隙115，保護材料層在進行圖案化製程以形成保護層117之前，可延伸填入壓電層112與第二電極114中的縫隙。在其他實施例中，縫隙也可能僅存在於第二電極114中，且保護材料層可僅延伸填入第二電極114中的縫隙。再者，在此些實施例中，保護層117也可作為調諧層(tuning layer)，可抑制聲波元件700運作時寄生模式(spurious mode)的影響，進而降低聲波元件700的***損耗以及改善寄生模式對聲波元件100頻寬範圍所造成的干擾。在一些實施例中，保護層117類似保護層116，可包括利用原子層沉積法形成的金屬氧化物或金屬氮化物。例如，金屬氧化物可包括氧化鋁、氧化鉿、氧化鋯、氧化鉭、氧化鈦或前述之組合。例如，金屬氮化物可包括氮化鋁、氮化鈦、氮化鋯、或氮化鉻。在一些實施例中，保護層117的厚度可介於約30nm至約70nm之間，例如約為50nm。 As described above, since the piezoelectric layer 112 on the first electrode 110 and the second electrode 114 may have a gap 115 as shown in FIG. 1G, the protective material layer may extend to fill the gap between the piezoelectric layer 112 and the second electrode 114 before the patterning process is performed to form the protective layer 117. In other embodiments, the gap may also exist only in the second electrode 114, and the protective material layer may only extend to fill the gap in the second electrode 114. Furthermore, in these embodiments, the protective layer 117 can also be used as a tuning layer to suppress the influence of the spurious mode when the acoustic wave element 700 is in operation, thereby reducing the insertion loss of the acoustic wave element 700 and improving the interference caused by the spurious mode on the bandwidth of the acoustic wave element 100. In some embodiments, the protective layer 117 is similar to the protective layer 116 and can include a metal oxide or a metal nitride formed by an atomic layer deposition method. For example, the metal oxide can include aluminum oxide, bismuth oxide, zirconium oxide, tantalum oxide, titanium oxide, or a combination thereof. For example, the metal nitride can include aluminum nitride, titanium nitride, zirconium nitride, or chromium nitride. In some embodiments, the thickness of the protective layer 117 may be between about 30 nm and about 70 nm, for example, about 50 nm.

接著，參照第7B圖，於第二電極114上形成用以調控頻率的保護層118。如第7B圖所示，保護層118可覆蓋保護層117的側壁與頂表面。接著，參照第7C圖，移除犧牲層104以於支撐基板102與種子層108之間形成空腔105。移除犧牲層104之後，空腔105沿著空腔105垂直向上延伸的區域之中定義出聲波元件700的主動區130。 Next, referring to FIG. 7B , a protective layer 118 for frequency modulation is formed on the second electrode 114 . As shown in FIG. 7B , the protective layer 118 can cover the sidewalls and top surface of the protective layer 117 . Next, referring to FIG. 7C , the sacrificial layer 104 is removed to form a cavity 105 between the supporting substrate 102 and the seed layer 108 . After removing the sacrificial layer 104 , the cavity 105 defines the active region 130 of the acoustic wave element 700 in the region where the cavity 105 extends vertically upward.

第7D至7F圖是根據各種實施例，繪示出具有保護層117的聲波元件700上視圖。應注意的是，為了簡化圖式，第7D至7F圖中省略了保護層118。參照第7D圖，在一些實施例中，保護層 117於上視圖中可具有環狀結構，且保護層117的環狀結構可環繞聲波元件700的主動區130並對應第一電極110的邊緣。相較於前述實施例中形成完整的保護層116，第7A至7F圖所示的保護層117僅形成環繞於聲波元件700主動區130的第一電極110邊緣，因此除了作為保護層外，可使聲波能量侷限於主動區130中進行共振以提高聲波元件700的效能，如以上所述，可作為調諧層而抑制聲波元件700的寄生模式。此外，應注意的是，第7A至7C圖的剖面是沿著第7D圖中的剖線A-A’所繪示。 FIGS. 7D to 7F are top views of an acoustic wave device 700 having a protective layer 117 according to various embodiments. It should be noted that the protective layer 118 is omitted in FIGS. 7D to 7F for the sake of simplicity. Referring to FIG. 7D , in some embodiments, the protective layer 117 may have a ring-shaped structure in the top view, and the ring-shaped structure of the protective layer 117 may surround the active region 130 of the acoustic wave device 700 and correspond to the edge of the first electrode 110. Compared to the protective layer 116 formed completely in the aforementioned embodiment, the protective layer 117 shown in FIGS. 7A to 7F is only formed around the edge of the first electrode 110 of the active region 130 of the acoustic wave element 700. Therefore, in addition to serving as a protective layer, the acoustic wave energy can be confined to the active region 130 for resonance to improve the performance of the acoustic wave element 700. As described above, it can serve as a tuning layer to suppress the parasitic mode of the acoustic wave element 700. In addition, it should be noted that the cross-sections of FIGS. 7A to 7C are drawn along the section line A-A’ in FIG. 7D.

根據本發明的其他實施例，如第7E圖所示，保護層117的環狀結構可具有減縮部140，減縮部140的寬度小於保護層117的環狀結構其他部位的寬度。應能理解的是，減縮部140可不侷限於第7E圖所示的位置，且可基於聲波元件700的設計需求，於保護層117環狀結構的任何位置具有減縮部140，使得聲波元件700具有較佳的性能(例如，高Q值)。此外，如第7F圖所示，在其他實施例中，保護層117的環狀結構可為不連續的結構。例如，基於聲波元件700的設計需求，保護層117的環狀結構可具有缺口145，而形成不相連的保護層117環狀結構。 According to other embodiments of the present invention, as shown in FIG. 7E , the annular structure of the protective layer 117 may have a reduced portion 140, and the width of the reduced portion 140 is smaller than the width of other parts of the annular structure of the protective layer 117. It should be understood that the reduced portion 140 is not limited to the position shown in FIG. 7E , and may be provided at any position of the annular structure of the protective layer 117 based on the design requirements of the acoustic wave element 700, so that the acoustic wave element 700 has better performance (for example, high Q value). In addition, as shown in FIG. 7F , in other embodiments, the annular structure of the protective layer 117 may be a discontinuous structure. For example, based on the design requirements of the acoustic wave element 700, the annular structure of the protective layer 117 may have a gap 145 to form an unconnected annular structure of the protective layer 117.

第8圖是根據其他實施例，繪示出具有元件區R1及周邊區R2的聲波元件800上視示意圖，且第9圖是根據其他實施例，沿著第8圖中的剖線B-B’繪示出聲波元件800的剖面示意圖。聲波元件800之部分製程及結構和聲波元件100類似，類似的製程及結構請參考聲波元件100之說明及圖式，不再贅述，後續將針對差異處詳細說明。應注意的是，為了簡化圖式，第8圖中僅繪示位於元件區R1的第一電極110及位於周邊區R2的金屬層111。參照第8圖及第9圖，聲波元件800包括支撐基板102，支撐基板102包括元件區R1及圍繞元件區R1的周邊區R2，在支撐基板102的元件區R1及周邊區R2上形成支撐層106及種子層108，在種子層108上對應元件區R1及周邊區R2的位置分別形成第一電極110及金屬層111，且壓電層112、保護層116及118進一步形成於第一電極110及金屬層111上。在一些實施例中，分別對應元件區R1及周邊區R2的第一電極110及金屬層111在空間上彼此分離，且可由同一層金屬形成，第一電極110及金屬層111的材料可包括鉬(Mo)、鋁(Al)、鈦(Ti)、鈦鎢合金(TiW)、銣(Ru)、銀(Ag)、銅(Cu)、金(Au)、鉑(Pt)或前述之組合。在一些實施例中，第一電極110及金屬層111的厚度可介於約0.01μm至約5μm之間。在一些實施例中，第一電極110及金屬層111的厚度可介於約0.1μm至約0.4μm之間。 FIG. 8 is a schematic top view of an acoustic wave element 800 having a device region R1 and a peripheral region R2 according to other embodiments, and FIG. 9 is a schematic cross-sectional view of the acoustic wave element 800 along the section line B-B' in FIG. 8 according to other embodiments. Some processes and structures of the acoustic wave element 800 are similar to those of the acoustic wave element 100. For similar processes and structures, please refer to the description and drawings of the acoustic wave element 100, and no further description will be given. The differences will be described in detail later. It should be noted that, in order to simplify the drawings, FIG. 8 only shows the first electrode 110 located in the device region R1 and the metal layer 111 located in the peripheral region R2. 8 and 9 , the acoustic wave element 800 includes a supporting substrate 102, the supporting substrate 102 includes a device region R1 and a peripheral region R2 surrounding the device region R1, a supporting layer 106 and a seed layer 108 are formed on the device region R1 and the peripheral region R2 of the supporting substrate 102, a first electrode 110 and a metal layer 111 are formed on the seed layer 108 at positions corresponding to the device region R1 and the peripheral region R2, respectively, and a piezoelectric layer 112, protective layers 116 and 118 are further formed on the first electrode 110 and the metal layer 111. In some embodiments, the first electrode 110 and the metal layer 111 corresponding to the device region R1 and the peripheral region R2 are separated from each other in space and may be formed by the same layer of metal. The materials of the first electrode 110 and the metal layer 111 may include molybdenum (Mo), aluminum (Al), titanium (Ti), titanium-tungsten alloy (TiW), ruthenium (Ru), silver (Ag), copper (Cu), gold (Au), platinum (Pt) or a combination thereof. In some embodiments, the thickness of the first electrode 110 and the metal layer 111 may be between about 0.01 μm and about 5 μm. In some embodiments, the thickness of the first electrode 110 and the metal layer 111 may be between about 0.1 μm and about 0.4 μm.

在第8、9圖所示的實施例中，元件區R1的支撐基板102與種子層108之間具有空腔105，而周邊區R2未具有空腔，且元件區R1的壓電層112上具有第二電極114，而周邊區R2未具有第二電極114。在一些實施例中，周邊區R2的金屬層111具有圖案，例如文字(如第8圖的上視圖中所示的文字SAMPLE)，作為元件辨識之用途。而元件區R1的第一電極110作為聲波元件的電極。由於第一電極110及金屬層111在圖案化設計上的差異，第一電極110的側壁及金屬層111的側壁與種子層108的上表面分別具有第一夾角 θ1及第二夾角θ2，且第二夾角θ2大於第一夾角θ1。於一實施例中，金屬層111於聲波元件800剖面圖中的形狀包含梯形形狀或矩形形狀，一般而言，具有梯形形狀或矩形形狀的金屬層111的頂角(即，金屬層111的側壁與頂表面之間的夾角)為一鈍角或一直角，而導致利用沉積製程於金屬層111上形成的膜層可能會在金屬層111頂角向外延伸的方向產生縫隙而衍生出前述問題，故在金屬層111上利用原子層沉積來形成高順應性的保護層116，保護層116可延伸填充金屬層111的縫隙，避免聲波元件的各個膜層在移除犧牲層的蝕刻製程時受損。 In the embodiment shown in FIGS. 8 and 9, the supporting substrate 102 and the seed layer 108 of the device region R1 have a cavity 105, while the peripheral region R2 has no cavity, and the piezoelectric layer 112 of the device region R1 has a second electrode 114, while the peripheral region R2 does not have the second electrode 114. In some embodiments, the metal layer 111 of the peripheral region R2 has a pattern, such as text (such as the text SAMPLE shown in the top view of FIG. 8), for device identification. The first electrode 110 of the device region R1 serves as the electrode of the acoustic wave device. Due to the difference in patterning design between the first electrode 110 and the metal layer 111, the sidewall of the first electrode 110 and the sidewall of the metal layer 111 and the upper surface of the seed layer 108 have a first angle θ1 and a second angle θ2, respectively, and the second angle θ2 is greater than the first angle θ1. In one embodiment, the shape of the metal layer 111 in the cross-sectional view of the acoustic wave element 800 includes a trapezoidal shape or a rectangular shape. Generally speaking, the top angle of the metal layer 111 having a trapezoidal shape or a rectangular shape (i.e., the angle between the sidewall and the top surface of the metal layer 111) is a blunt angle or a right angle, resulting in the formation of a first angle θ1 on the metal layer 111 by a deposition process. The film layer formed may produce gaps in the direction where the top corners of the metal layer 111 extend outward, resulting in the aforementioned problems. Therefore, an atomic layer deposition is used on the metal layer 111 to form a highly compliant protective layer 116. The protective layer 116 can extend to fill the gaps of the metal layer 111 to prevent the film layers of the acoustic wave element from being damaged during the etching process of removing the sacrificial layer.

在製造聲波元件的過程中，由於形成的第一電極一般會具有鈍角或甚至是直角的頂角，使得其上形成的各個膜層可能會沿著第一電極頂角向外延伸的方向產生縫隙。在後續移除犧牲層的蝕刻製程時，特別是對於使用氣相氟化氫蝕刻製程，蝕刻製程的蝕刻劑可能會沿著上述的縫隙侵入聲波元件並侵蝕各個膜層，進而導致聲波元件功能失效。本發明實施例提供的聲波元件的製造方法利用原子層沉積來形成高順應性的保護層，保護層可延伸填充第一電極之上各個膜層的縫隙，避免聲波元件的各個膜層在移除犧牲層的蝕刻製程時受損。另一方面，利用原子層沉積形成的保護層也可形成於第一電極之下(例如，第一電極與種子層之間，或種子層與支撐基板之間)，能夠防止移除犧牲層的蝕刻製程所使用的蝕刻劑在移除犧牲層之後，進一步侵蝕種子層與第一電極而導致聲波元件功能失效。此外，利用原子層沉積於第一電極與壓電層之間或種子層與第一電極之間形成的保護層，由於其高緻密性，可提供較為平坦的表面，因而進一步改善第一電極(保護層形成於第一電極與種子層之間)或種子層(保護層形成於種子層之下)具有較高表面粗糙度的問題且為聲波元件提供良好的結構穩定性。 In the process of manufacturing an acoustic wave device, since the first electrode generally has a blunt or even right-angled top angle, each film layer formed thereon may generate a gap along the direction in which the top angle of the first electrode extends outward. In the subsequent etching process for removing the sacrificial layer, especially for the etching process using gas phase hydrogen fluoride, the etchant of the etching process may invade the acoustic wave device along the above-mentioned gap and erode each film layer, thereby causing the acoustic wave device to fail. The manufacturing method of the acoustic wave element provided by the embodiment of the present invention utilizes atomic layer deposition to form a highly compliant protective layer, and the protective layer can extend to fill the gaps of each film layer on the first electrode to prevent each film layer of the acoustic wave element from being damaged during the etching process of removing the sacrificial layer. On the other hand, the protective layer formed by atomic layer deposition can also be formed under the first electrode (for example, between the first electrode and the seed layer, or between the seed layer and the supporting substrate), which can prevent the etchant used in the etching process of removing the sacrificial layer from further corroding the seed layer and the first electrode after removing the sacrificial layer, thereby causing the acoustic wave element to fail. In addition, the protective layer formed by atomic layer deposition between the first electrode and the piezoelectric layer or between the seed layer and the first electrode can provide a relatively flat surface due to its high density, thereby further improving the problem of high surface roughness of the first electrode (the protective layer is formed between the first electrode and the seed layer) or the seed layer (the protective layer is formed under the seed layer) and providing good structural stability for the acoustic wave element.

以上概述數個實施例之部件，以便在本發明所屬技術領域中具有通常知識者可更易理解本發明實施例的觀點。在本發明所屬技術領域中具有通常知識者應理解，他們能以本發明實施例為基礎，設計或修改其他製程和結構，以達到與在此介紹的實施例相同之目的及/或優勢。在本發明所屬技術領域中具有通常知識者也應理解到，此類等效的製程和結構並無悖離本發明的精神與範圍，且他們能在不違背本發明之精神和範圍之下，做各式各樣的改變、取代和替換。 The above summarizes the components of several embodiments so that those with ordinary knowledge in the art to which the present invention belongs can more easily understand the viewpoints of the embodiments of the present invention. Those with ordinary knowledge in the art to which the present invention belongs should understand that they can design or modify other processes and structures based on the embodiments of the present invention to achieve the same purpose and/or advantages as the embodiments introduced herein. Those with ordinary knowledge in the art to which the present invention belongs should also understand that such equivalent processes and structures do not violate the spirit and scope of the present invention, and they can make various changes, substitutions and replacements without violating the spirit and scope of the present invention.

200:聲波元件 200: Acoustic wave element

102:支撐基板 102: Supporting substrate

105:空腔 105: Cavity

106:支撐層 106: Support layer

108:種子層 108: Seed layer

110:第一電極 110: First electrode

112:壓電層 112: Piezoelectric layer

114:第二電極 114: Second electrode

118:保護層 118: Protective layer

Claims

一種聲波元件，包括：一支撐基板；一種子層，形成於該支撐基板之上，其中該支撐基板與該種子層間具有一空腔；一第一電極，形成於該種子層之上；一壓電層，形成於該第一電極之上；一第二電極，形成該壓電層之上，其中該第二電極具有一電極縫隙；以及一第一保護層，形成於該第二電極之上並延伸填入該電極縫隙，其中該第一保護層係利用原子層沉積法所形成。 An acoustic wave element includes: a supporting substrate; a seed layer formed on the supporting substrate, wherein a cavity is provided between the supporting substrate and the seed layer; a first electrode formed on the seed layer; a piezoelectric layer formed on the first electrode; a second electrode formed on the piezoelectric layer, wherein the second electrode has an electrode gap; and a first protective layer formed on the second electrode and extending to fill the electrode gap, wherein the first protective layer is formed by atomic layer deposition.

如請求項1所述之聲波元件，其中該壓電層具有一壓電層縫隙，該第一保護層延伸填入該壓電層縫隙。 The acoustic wave element as described in claim 1, wherein the piezoelectric layer has a piezoelectric layer gap, and the first protective layer extends to fill the piezoelectric layer gap.

如請求項2所述之聲波元件，其中該空腔定義出一主動區，且該第一保護層於上視圖中具有一環狀結構，該環狀結構環繞該主動區。 The acoustic wave element as described in claim 2, wherein the cavity defines an active area, and the first protective layer has an annular structure in the top view, and the annular structure surrounds the active area.

如請求項3所述之聲波元件，其中該環狀結構的一部分具有減縮的寬度，或其中該環狀結構為一非連續的環狀結構。 An acoustic wave element as described in claim 3, wherein a portion of the annular structure has a reduced width, or wherein the annular structure is a discontinuous annular structure.

一種聲波元件，包括：一支撐基板；一種子層，形成於該支撐基板之上，其中該支撐基板與該種子層間具有一空腔；一第一電極，形成於該種子層之上；一壓電層，形成於該第一電極之上；一第二電極，形成該壓電層之上；以及一第一保護層，形成於該種子層與該第二電極之間，其中該第一保護層係利用原子層沉積法所形成。 An acoustic wave element includes: a supporting substrate; a seed layer formed on the supporting substrate, wherein a cavity is provided between the supporting substrate and the seed layer; a first electrode formed on the seed layer; a piezoelectric layer formed on the first electrode; a second electrode formed on the piezoelectric layer; and a first protective layer formed between the seed layer and the second electrode, wherein the first protective layer is formed by atomic layer deposition.

如請求項5所述之聲波元件，其中該壓電層具有一壓電層縫隙，該第一保護層形成於該壓電層與該第二電極之間並延伸填入該壓電層縫隙。 The acoustic wave element as described in claim 5, wherein the piezoelectric layer has a piezoelectric layer gap, and the first protective layer is formed between the piezoelectric layer and the second electrode and extends to fill the piezoelectric layer gap.

如請求項5所述之聲波元件，其中該第一保護層形成於該第一電極與該壓電層之間。 An acoustic wave device as described in claim 5, wherein the first protective layer is formed between the first electrode and the piezoelectric layer.

如請求項5所述之聲波元件，其中該第一保護層形成於該種子層與該第一電極之間。 The acoustic wave element as described in claim 5, wherein the first protective layer is formed between the seed layer and the first electrode.

一種聲波元件，包括：一支撐基板；一種子層，形成於該支撐基板之上，其中該支撐基板與該種子層間具有一空腔；一第一電極，形成於該種子層之上；一壓電層，形成於該第一電極之上；一第二電極，形成該壓電層之上；以及一第一保護層，形成於該種子層之下，其中該第一保護層係利用原子層沉積法所形成。 An acoustic wave element includes: a supporting substrate; a seed layer formed on the supporting substrate, wherein a cavity is provided between the supporting substrate and the seed layer; a first electrode formed on the seed layer; a piezoelectric layer formed on the first electrode; a second electrode formed on the piezoelectric layer; and a first protective layer formed under the seed layer, wherein the first protective layer is formed by atomic layer deposition.

如請求項4至9中任一項所述之聲波元件，更包括一第二保護層，該第二保護層形成於該第一保護層上，且該第二保護層包括氮化矽、Sc_xAl_1-xN或前述之組合，其中x小於1且大於或等於0。 The acoustic wave device as described in any one of claims 4 to 9 further includes a second protective layer formed on the first protective layer, and the second protective layer includes silicon nitride, Sc _x Al _1-x N or a combination thereof, wherein x is less than 1 and greater than or equal to 0.