Piezoelectric resonator element and method of manufacturing same

Abstract

A piezoelectric resonator element and method of manufacturing same are provided. The piezoelectric resonator element having a lower electrode, a piezoelectric substance layer, and an upper electrode disposed in this order on a substrate with an air layer between the substrate and the lower electrode, and having a laminated structure of the lower electrode, the piezoelectric substance layer, and the upper electrode in at least a part of the piezoelectric resonator element, wherein internal stress of the piezoelectric substance layer is -300 MPa to 90 MPa.

Description

technical field

[0001] The present invention relates to a piezoelectric resonant element and a manufacturing method thereof, in particular to a manufacturing method of a Thin Film Bulk Acoustic Resonator (FBAR) utilizing the electroacoustic effect exhibited by a piezoelectric layer and the FBAR. Background technique

[0002] In recent years, with the increase in functionality and speed of mobile phones and PDAs, high-frequency filters operating at hundreds of MHz to several GHz built into these communication devices have been increasing, and miniaturization and cost reduction have been demanded. A strong candidate for a high-frequency filter satisfying such a requirement is a filter using an FBAR, which can be formed using semiconductor manufacturing technology.

[0003] As a representative example of this FBAR, Figure 6 An example of a structure called an air bridge type is shown (for example, refer to Non-Patent Document 1). Figure 6 (a) represents a sectional view, Fig...

Examples

no. 1 approach

[0033]In the present example, as an example of an embodiment of the first piezoelectric resonant element of the present invention, the pass frequency range will be described using an example of FBAR at 2 GHz. figure 1 (a) represents a sectional view, figure 1 (b) represents a floor plan, figure 1 (a) is figure 1 (b) A-A' line profile. In addition, the same code|symbol is attached|subjected to the same structure as demonstrated in background art, and it demonstrates.

[0034] Such as figure 1 As shown in (a), a structure 16 is provided on a substrate 11 made of high-resistance silicon or high-resistance gallium arsenide. In this structure 16, a lower electrode 13 and a piezoelectric body are sequentially formed with an air layer 12 in between. layer 14 and upper electrode 15.

[0035] The lower electrode 13 is provided with a thickness of 0.1 μm to 0.5 μm while covering the air layer 12 and extending in one direction on the substrate 11 (see figure 1 (b)). Examples...

Embodiment 1～10

[0054] Such as figure 1 As shown, a plurality of FBARs of Examples 1 to 10 in which the internal stress of the piezoelectric layer 14 was varied within a range of not less than -300 MPa and not more than 90 MPa were produced by the same method as the example. Table 1 shows the internal stress of the piezoelectric layer 14 in each manufactured FBAR. The internal stress of the piezoelectric layer 14 was measured by the amount of warpage of the substrate 11 that occurred when the piezoelectric layer 14 made of an AlN film was formed on the substrate 11 provided with the lower electrode 13 .

[0055] Example 1

technical field

[0001] The present invention relates to a piezoelectric resonant element and a manufacturing method thereof, in particular to a manufacturing method of a Thin Film Bulk Acoustic Resonator (FBAR) utilizing the electroacoustic effect exhibited by a piezoelectric layer and the FBAR. Background technique

[0002] In recent years, with the increase in functionality and speed of mobile phones and PDAs, high-frequency filters operating at hundreds of MHz to several GHz built into these communication devices have been increasing, and miniaturization and cost reduction have been demanded. A strong candidate for a high-frequency filter satisfying such a requirement is a filter using an FBAR, which can be formed using semiconductor manufacturing technology.

[0003] As a representative example of this FBAR, Figure 6 An example of a structure called an air bridge type is shown (for example, refer to Non-Patent Document 1). Figure 6 (a) represents a sectional view, Fig...

Examples

no. 1 approach

[0033]In the present example, as an example of an embodiment of the first piezoelectric resonant element of the present invention, the pass frequency range will be described using an example of FBAR at 2 GHz. figure 1 (a) represents a sectional view, figure 1 (b) represents a floor plan, figure 1 (a) is figure 1 (b) A-A' line profile. In addition, the same code|symbol is attached|subjected to the same structure as demonstrated in background art, and it demonstrates.

[0034] Such as figure 1 As shown in (a), a structure 16 is provided on a substrate 11 made of high-resistance silicon or high-resistance gallium arsenide. In this structure 16, a lower electrode 13 and a piezoelectric body are sequentially formed with an air layer 12 in between. layer 14 and upper electrode 15.

[0035] The lower electrode 13 is provided with a thickness of 0.1 μm to 0.5 μm while covering the air layer 12 and extending in one direction on the substrate 11 (see figure 1 (b)). Examples...

Embodiment 1～10

[0054] Such as figure 1 As shown, a plurality of FBARs of Examples 1 to 10 in which the internal stress of the piezoelectric layer 14 was varied within a range of not less than -300 MPa and not more than 90 MPa were produced by the same method as the example. Table 1 shows the internal stress of the piezoelectric layer 14 in each manufactured FBAR. The internal stress of the piezoelectric layer 14 was measured by the amount of warpage of the substrate 11 that occurred when the piezoelectric layer 14 made of an AlN film was formed on the substrate 11 provided with the lower electrode 13 .

[0055] Example 1

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