TWI440302B - Film bulk acoustic resonator and manufacturing method thereof - Google Patents

Description

Bulk acoustic wave thin film resonator and manufacturing method thereof

The present invention relates to a bulk acoustic wave thin film resonator, and more particularly to a bulk acoustic wave thin film resonator capable of increasing the signal blocking of a bulk acoustic wave resonant element.

In recent years, the body acoustic wave thin film resonator (FBAR) has become a better feature because the component size of the bulk acoustic wave thin film resonator can be reduced smaller, the frequency characteristics are better, and the quality and characteristics of the overall wireless communication system can be improved. Development focus, as shown in FIG. 5, a bulk acoustic wave thin film resonator 10 including a plurality of individual acoustic thin film resonant elements includes a germanium substrate 11, a first metal layer 12, a piezoelectric layer 13, and a second metal. The first metal layer 12 is formed on the ruthenium substrate 11 , and the first metal layer 12 has a plurality of lower electrodes 12 a formed on the ruthenium substrate 11 and covering the first layer a metal layer 12, the second metal layer 14 is formed on the piezoelectric layer 13, and the second metal layer 14 includes a first upper electrode 14a, a second upper electrode 14b and a third upper electrode 14c. The bulk acoustic wave thin film resonator 10 converts the deformation of mechanical energy through the piezoelectric layer 13 into an electrical signal by a piezoelectric effect, but the vibration energy of the bulk acoustic wave thin film resonator 10 does not have a fixed directivity due to mechanical vibration. Therefore, mechanical vibration energy will The piezoelectric layer 13 by a conductive, thus causing signal interference, resulting in signal quality Not good.

The main object of the present invention is to provide a bulk acoustic wave thin film resonator comprising a germanium substrate, a first metal layer, a piezoelectric layer and a second metal layer, the germanium substrate having a first surface and a first a second surface, the first metal layer is formed on the germanium substrate, and the first metal layer includes a plurality of lower electrodes formed on the germanium substrate and covering the first metal layer. The piezoelectric layer has at least a first upper electrode setting area, a second upper electrode setting area, a third upper electrode setting area, a first blocking area outside the first upper electrode setting area, and a first blocking area a second blocking area outside the upper electrode setting area and a third blocking area outside the third upper electrode setting area, wherein the first blocking area is formed with at least one first trench, and the second blocking area is Forming at least one second trench, the third barrier region is formed with at least one third trench, the second metal layer is formed on the piezoelectric layer, and the second metal layer comprises a first upper electrode a second upper electrode and a third upper electrode, A first upper electrode based on the electrode disposed at the first region, the second upper electrode based on the electrode disposed at the second region, located on the third electrode system disposed on the third electrode region. Since the bulk acoustic wave thin film resonator converts the deformation of mechanical energy through the piezoelectric layer into an electrical signal by using a piezoelectric effect, the present invention separately forms the first trench in the first blocking region of the piezoelectric layer, In the piezoelectric layer The second barrier region forms the second trench and the third barrier region of the piezoelectric layer forms the third trench, so that the mechanical vibration generated by the bulk acoustic wave thin film resonator is caused by the piezoelectric layer a trench, a second trench, and a third trench are blocked, so that most of the vibration energy is limited to the vertical structure of the bulk acoustic thin film resonator to increase the signal resonance intensity of the bulk acoustic thin film resonator. And reduce signal interference.

1 and 2 are a preferred embodiment of the present invention. A bulk acoustic wave thin film resonator 100 includes a germanium substrate 110, a first metal layer 120, a piezoelectric layer 130, and a second metal. In the layer 140, the first substrate 111 and the second surface 112 are formed on the substrate 110. In the embodiment, the first metal layer 120 is formed on the substrate 110. A plurality of lower electrodes 121 are disposed, and the piezoelectric layer 130 covers the first metal layer 120. The piezoelectric layer 130 is selected from the group consisting of aluminum nitride, zinc oxide or barium sulfide, and the piezoelectric layer 130 is at least The first upper electrode setting area 131, the second upper electrode setting area 132, the third upper electrode setting area 133, and the first blocking area 134 located outside the first upper electrode setting area 131 are located at the first a second barrier region 135 outside the second upper electrode setting region 132 and a third barrier region 136 outside the third upper electrode region 133, wherein the first barrier region 134 is formed with at least one first trench 137. The second resistance The partition 135 is formed with at least one second trench 138. The third barrier region 136 is formed with at least one third trench 139. The second metal layer 140 is formed on the piezoelectric layer 130. The metal layer 140 includes a first upper electrode 141, a second upper electrode 142, and a third upper electrode 143, and the first upper electrode 141 and the second upper electrode 142 are arranged in series, and the first upper electrode 141 and the third upper electrode 143 are disposed in parallel, the second upper electrode 142 and the third upper electrode 143 are also disposed in parallel, and the first upper electrode 141 is located in the first upper electrode setting area 131, the first The second upper electrode 142 is located in the second upper electrode setting area 132, and the third upper electrode 143 is located in the third upper electrode setting area 133. The materials of the first metal layer 120 and the second metal layer 140 are selected from Metal materials such as aluminum, gold, molybdenum or platinum.

Referring to FIGS. 1 and 2, the first trench 137 is located between the first upper electrode setting region 131 and the third upper electrode setting region 133, and the second trench 138 is located at the second upper electrode. The first trench 137 has a first long trench 137a and two are respectively located on opposite sides of the first long trench 137a. The first trench 137 is disposed on the two sides of the first long trench 137a. a first short trench 137b having a second long trench 138a and two second short trenches 138b respectively on opposite sides of the second long trench 138a, the third trench 139 having a third long groove 139a and two are respectively located in the first a third short trench 139b on the two sides of the three long trenches 139a, at least one first short trench 137b is located between the first upper electrode setting region 131 and the second upper electrode setting region 132, and at least a second short trench The groove 138b is located between the second upper electrode setting region 132 and the first upper electrode setting region 131, and the bulk acoustic wave thin film resonator 100 converts the deformation of the mechanical energy through the piezoelectric layer 130 into a piezoelectric effect. The first groove 137 is formed in the first barrier region 134 of the piezoelectric layer 130, and the second barrier region 135 forms the second trench 138 and the third barrier region 136 is formed. The third trench 139 is such that the mechanical vibration generated by the bulk acoustic wave thin film resonator 100 is blocked by the first trench 137, the second trench 138 and the third trench 139 of the piezoelectric layer 130, so most of the The vibration energy will be limited to the vertical structure of the bulk acoustic wave thin film resonator 100 to increase the signal resonance intensity of the bulk acoustic wave thin film resonator 100 and reduce signal interference.

Next, please refer to FIGS. 3A to 4B, which are a manufacturing method of the bulk acoustic wave thin film resonator 100 of the present invention. First, referring to FIG. 3A, a substrate 110 is provided, and the first substrate 110 has a first a surface 111, a second surface 112, a vibration layer 113 formed on the first surface 111, and an etch mask layer 114 formed on the second surface 112. Next, referring to FIG. 3B, a resonant cavity 115 is formed. After the second surface 112, and then forming a first metal layer 120 on the germanium substrate On the vibration layer 113 of the 110, the first metal layer 120 includes a plurality of lower electrodes 121; then, referring to FIGS. 3C and 4A, a piezoelectric layer 130 is formed on the vibration layer 113 of the germanium substrate 110. And covering the first metal layer 120, the piezoelectric layer 130 has at least a first upper electrode setting area 131, a second upper electrode setting area 132, a third upper electrode setting area 133, and one on the first a first blocking region 134 outside the electrode setting region 131, a second blocking region 135 outside the second upper electrode setting region 132, and a third blocking region 136 outside the third upper electrode setting region 133; Referring to FIG. 4B, at least one first trench 137 is formed in the first barrier region 134, at least one second trench 138 is formed in the second barrier region 135, and at least a third trench 139 is formed in the third region. In the present embodiment, the first trench 137, the second trench 138, and the third trench 139 are formed by a laser shaving method. Preferably, the first trench 137 is located. Between the first upper electrode setting area 131 and the third upper electrode setting area 133, the second trench 138 is located In the present embodiment, the first trench 137 has a first long trench 137a and two of the first long trench 137a respectively located in the first long trench 137a. a first short trench 137b on the two sides, the second trench 138 has a second long trench 138a and two second short trenches 138b respectively on the two sides of the second long trench 138a, the third trench The 139 series has a third long groove 139a And a third short trench 139b respectively located on two sides of the third long trench 139a, the first short trench 137b being located between the first upper electrode setting region 131 and the second upper electrode setting region 132, The second short trench 138b is located between the second upper electrode setting region 132 and the first upper electrode setting region 131; finally, as shown in FIG. 1, a second metal layer 140 is formed on the piezoelectric layer. The second metal layer 140 includes a first upper electrode 141, a second upper electrode 142, and a third upper electrode 143. The first upper electrode 141 is located in the first upper electrode setting region 131. The second upper electrode 142 is located in the second upper electrode setting region 132, and the third upper electrode 143 is located in the third upper electrode setting region 133 to form the bulk acoustic wave thin film resonator 100.

The scope of the present invention is defined by the scope of the appended claims, and any changes and modifications made by those skilled in the art without departing from the spirit and scope of the invention are within the scope of the present invention. .

10‧‧‧Body Acoustic Thin Film Resonator

11‧‧‧矽 substrate

12‧‧‧First metal layer

12a‧‧‧ lower electrode

13‧‧‧Piezoelectric layer

14‧‧‧Second metal layer

14a‧‧‧First upper electrode

14b‧‧‧Second upper electrode

14c‧‧‧ third upper electrode

100‧‧‧Body Acoustic Thin Film Resonator

110‧‧‧矽 substrate

111‧‧‧ first surface

112‧‧‧ second surface

113‧‧‧Vibration layer

114‧‧‧ etching mask layer

115‧‧‧Resonance cavity

120‧‧‧First metal layer

121‧‧‧ lower electrode

130‧‧‧Piezoelectric layer

131‧‧‧First upper electrode setting area

132‧‧‧Second upper electrode setting area

133‧‧‧ Third upper electrode setting area

134‧‧‧First barrier zone

135‧‧‧second barrier zone

136‧‧‧ third barrier zone

137‧‧‧first trench

137a‧‧‧First long groove

137b‧‧‧ first short groove

138‧‧‧Second trench

138a‧‧‧Second long trench

138b‧‧‧Second short groove

139‧‧‧ third trench

139a‧‧‧3rd long groove

139b‧‧‧ third short groove

140‧‧‧Second metal layer

141‧‧‧First upper electrode

142‧‧‧Second upper electrode

143‧‧‧ third upper electrode

Figure 1 is a top plan view of a bulk acoustic wave thin film resonator in accordance with a preferred embodiment of the present invention.

2 is a perspective cross-sectional view of the bulk acoustic wave thin film resonator in accordance with a preferred embodiment of the present invention.

3A to 3C are cross-sectional views showing a method of manufacturing the bulk acoustic wave thin film resonator according to a preferred embodiment of the present invention.

4A to 4B are perspective views of a method of manufacturing the bulk acoustic wave thin film resonator according to a preferred embodiment of the present invention.

Figure 5: A perspective view of a conventional bulk acoustic wave thin film resonator.

100‧‧‧Body Acoustic Thin Film Resonator

110‧‧‧矽 substrate

111‧‧‧ first surface

112‧‧‧ second surface

120‧‧‧First metal layer

121‧‧‧ lower electrode

130‧‧‧Piezoelectric layer

137‧‧‧first trench

137a‧‧‧First long groove

137b‧‧‧ first short groove

138‧‧‧Second trench

138a‧‧‧Second long trench

138b‧‧‧Second short groove

140‧‧‧Second metal layer

141‧‧‧First upper electrode

142‧‧‧Second upper electrode

143‧‧‧ third upper electrode

Claims (9)

A bulk acoustic wave thin film resonator comprising: a germanium substrate having a first surface and a second surface; a first metal layer formed on the germanium substrate, the first metal layer comprising a plurality of lower electrodes; a piezoelectric layer covering the first metal layer, the piezoelectric layer having at least a first upper electrode setting region, a second upper electrode setting region, and a third upper electrode setting region a first blocking region outside the first upper electrode setting region, a second blocking region outside the second upper electrode setting region, and a third blocking region outside the third upper electrode setting region, wherein The first barrier region is formed with at least one first trench, the second barrier region is formed with at least one second trench, the third barrier region is formed with at least one third trench; and a second metal a layer formed on the piezoelectric layer, the second metal layer includes a first upper electrode, a second upper electrode and a third upper electrode, wherein the first upper electrode is located at the first upper electrode a second upper electrode is located at the second upper electrode Region, and the third located on the electrode system disposed on the third electrode region. The bulk acoustic wave thin film resonator according to claim 1, wherein the first trench is located between the first upper electrode setting region and the third upper electrode setting region, and the second trench is located at the a second upper electrode setting area and the third upper electrode setting Between the districts. The bulk acoustic wave thin film resonator according to claim 1, wherein the first trench has a first long trench and two first short trenches respectively located on two sides of the first long trench, the first trench The second trench has a second long trench and two second short trenches respectively located on two sides of the second long trench, the third trench has a third long trench and two third trenches respectively located in the third trench The third short groove on the two sides of the groove. The bulk acoustic wave thin film resonator according to claim 3, wherein the first short trench is located between the first upper electrode setting region and the second upper electrode setting region, the second short trench system Located between the second upper electrode setting area and the first upper electrode setting area. A method for manufacturing a bulk acoustic wave thin film resonator, comprising: providing a germanium substrate having a first surface and a second surface; forming a first metal layer on the germanium substrate, the first metal The layer system includes a plurality of lower electrodes; a piezoelectric layer is formed on the germanium substrate and covers the first metal layer, the piezoelectric layer has at least a first upper electrode setting region, a second upper electrode setting region, and a a third upper electrode setting area, a first blocking area outside the first upper electrode setting area, and a second outer side of the second upper electrode setting area a barrier region and a third barrier region outside the third upper electrode installation region; forming at least one first trench in the first barrier region, forming at least one second trench in the second barrier region and forming at least one a third trench is disposed in the third barrier region; and a second metal layer is formed on the piezoelectric layer, the second metal layer includes a first upper electrode, a second upper electrode, and a third upper electrode. The first upper electrode is located in the first upper electrode setting region, the second upper electrode is located in the second upper electrode setting region, and the third upper electrode is located in the third upper electrode setting region. The method of manufacturing a bulk acoustic wave thin film resonator according to claim 5, wherein the first trench, the second trench, and the third trench are formed by a laser shaving method. The manufacturing method of the bulk acoustic wave thin film resonator according to the fifth aspect of the invention, wherein the first trench is located between the first upper electrode setting region and the third upper electrode setting region, the second trench The system is located between the second upper electrode setting area and the third upper electrode setting area. The method for manufacturing a bulk acoustic wave thin film resonator according to claim 5, wherein the first trench has a first long trench and two first short trenches respectively located on two sides of the first long trench The second trench has a second long trench and two second short trenches respectively located on two sides of the second long trench groove. The manufacturing method of the bulk acoustic wave thin film resonator according to claim 8, wherein the first short trench is located between the first upper electrode setting region and the second upper electrode setting region, the second short The trench is located between the second upper electrode setting region and the first upper electrode setting region.