TWI753067B - Monolithic integrated device - Google Patents

Abstract

This disclosure describes a monolithic integrated device having an architecture that allows the acoustic device to transduce either the surface acoustic waves or the bulk acoustic waves. The monolithic integrated device comprises a substrate layer (101) being the base of the monolithic integrated device; an inter-layer dielectric (102) disposed on top of the substrate layer (101); an electronic circuitry substantially formed in the inter-layer dielectric (102) and supported by the substrate layer (101), the electronic circuitry comprises a plurality of metal layers formed by one or more spaced apart metals (204); and a piezoelectric (301)being sandwiched between a top electrode and a bottom electrode within the inter-layer dielectric. The top electrode is a metal (204) of an upper metal layer belonging to the electronic circuitry and the bottom electrode is a metal (204) of a lower metal layer belonging to the electronic circuitry. In order to transduce bulk acoustic waves, the inter-layer dielectric is formed with a top cavity (105) above the top electrode and a bottom cavity (106) below the bottom electrode.

Description

Single stone integrated device

The present invention relates to components in the semiconductor field, and more particularly to monolithic integrated devices that can be used in controlled frequency circuit design applications.

Acoustic elements facilitate frequency filtering to enable transmission and reception of signals of specific bandwidths. Such elements are conventionally used in broadcast radio, television and mobile communications applications. The numerous functions of these passive acoustic wave components are by integrating them with active circuits to form various components such as oscillators, active filters, low noise amplifiers, mass sensors, temperature sensors, etc. . These electronic circuits fabricated by complementary-metal-oxide semiconductor (CMOS) technology and acoustic elements fabricated by micro-electro mechanical systems (MEMS) technology are mounted on a laminated board (laminated board). ) or silicon interposer.

Typically, the integration of electronic circuits and acoustic components is achieved by monolithic or heterogeneous integration methods, where the acoustic components are built on top of the electronic circuits. Monolithic integration provides a better solution than heterogeneous integration. US20060202779A1 describes an example of a monolithic integrated device comprising a substrate, an electronic circuit supported by the substrate, an acoustic isolator over the electronic circuit, and an acoustic resonator on the acoustic isolator for transducing bulk acoustic waves (bulk acoustic wave). acoustic harmonics The vibrator is vertically integrated with the electronic circuit in a single monolithic element. Such elements have the characteristics of shortening the signal propagation distance between the acoustic resonator and the electronic circuit and reducing the number of connections, thus resulting in improved performance and sensitivity of the monolithic integrated device, and reduced size of the monolithic integrated device, while being compatible with the Acoustic resonators increase the number of acoustic resonator elements and electronic circuit elements that can be fabricated within a given area of a substrate compared to monolithic integrated devices in which electronic circuits are laterally integrated.

Another example of a monolithic integrated device disclosed in US5260596A describes a monolithic circuit die integrated with a bulk structure resonator. The wafer contains a plurality of integrated circuit elements fabricated as part of a semiconductor substrate mounted with springs for supporting the mass. The invention includes an excitation device for applying a varying electrostatic force to a mass to induce mechanical vibrations in the mass. Cavities fabricated on the semiconductor substrate provide room for mechanical vibrations to occur. Other embodiments of the invention include the use of non-piezoelectric mechanical resonators, quartz crystal resonators and thin film piezoelectric resonators capable of generating surface acoustic waves or bulk acoustic waves.

Conventional monolithic devices, especially those configured to have acoustic components built on top of the CMOS components' electronic circuitry, create complexity and compatibility issues between the acoustic components and the CMOS components, which can lead to sacrificing the functionality of the acoustic element. Accordingly, the invention disclosed herein aims to provide solutions to these problems.

One of the objects of the present invention is to provide a monolithic integrated device having reduced interconnect electronic parasitic effects by embedding the acoustic element in the electronic circuit of the CMOS element and using the metal layer of the electronic circuit as the electrode of the acoustic element )Structure.

Another object of the present invention is to provide a monolithic integrated device having reduced interconnect electronic parasitic effects by embedding the acoustic element within the electronic circuit of the CMOS element and utilizing the metal layer of the electronic circuit as the electrode of the acoustic element )Structure.

Another object of the present invention is to provide a monolithic integrated device having a structure that allows the integration of an acoustic element with an electronic circuit with or without a passivation layer.

Another object of the present invention is to provide a monolithic integrated device that enables an acoustic element to be electronically disconnected from an active electronic circuit so that the acoustic element can be used for a passive element.

Another object of the present invention is a monolithic integrated device having a simplified element structure and configuration while enhancing compatibility between acoustic elements and CMOS elements without sacrificing the functionality of the acoustic elements.

Through the present invention satisfying at least one of the above aspects in whole or in part, a preferred embodiment of the present invention describes a monolithic integrated device, comprising: a base layer as the substrate of the monolithic integrated device; an electrical circuit disposed on top of the base layer; an electronic circuit formed substantially in the interlayer dielectric and supported by the base layer, the electronic circuit comprising a plurality of metals formed from one or more spaced-apart metal layer; and a piezoelectric body sandwiched between a top electrode and a bottom electrode within the interlayer dielectric; wherein the top electrode is a metal belonging to the upper metal layer of the electronic circuit and the bottom electrode is a metal belonging to the upper metal layer of the electronic circuit The metal of the lower metal layer of the electronic circuit. This structure allows the conduction of surface acoustic waves. To conduct bulk acoustic waves, cavities are formed above the top electrode and below the bottom electrode.

101: Substrate layer

102: Interlayer dielectric

103: Passivation layer

104: Bond pad opening

105, 106: cavity

201: Gate

202: Source and drain regions

203: Contact element

204: Metal

205: Through hole

301: Piezoelectric

Figure 1 shows a schematic diagram of a monolithic integrated device having a structure that allows the acoustic element to conduct surface acoustic waves.

Figure 2 shows a schematic diagram of a monolithic integrated device having a structure that allows conduction of surface or bulk acoustic waves through the acoustic element.

For a better understanding of the present invention, preferred embodiments of the present invention shown in the accompanying drawings will be described in detail.

The invention disclosed herein relates to a monolithic integrated device that integrates an acoustic element with an electronic circuit fabricated by complementary metal oxide semiconductor technology. Depending on the type of electronic circuit and acoustic elements, monolithic integrated devices can be formed as oscillators, active filters, low noise amplifiers, mass sensors, temperature sensors, etc. through the integration of acoustic elements that generate electrical charges in response to applied mechanical stress. Acoustic wave elements, which are passive electronic frequency generators, are generally formed of piezoelectrics sandwiched between top and bottom electrodes. It should be noted that the term "electronic circuit" as used herein refers to an active circuit comprising an electronic element or electronic elements connected by electrical connections such as CMOS elements.

Referring to Figures 1 and 2, a monolithic integrated device has a base layer (101) that serves as a base for the element. The base layer (101) is made of a semiconductor such as but not limited to silicon. An inter-layer dielectric (102) is provided on top of the base layer (101), wherein electronic circuits are substantially formed between the base layer (101) and the inter-layer dielectric (102) and are supported by the base layer (101) )support.

The electronic circuit comprises at least one gate (201) in a base layer (101), at least one source and drain in an interlayer dielectric (102) and having a source and a drain respectively connected to the gate (201) electrode regions (202), a plurality of metal layers formed from one or more spaced-apart metals (204), at least one contact element (203) for connecting the source and drain regions (202) and the gate (204) 201) in Any one or a combination of these are connected to one of a plurality of metals (204), and vias (205) for connecting different metal layers.

The gate (201), source and drain are the terminals of a field-effect transistor (FET) that uses an electric field to control the current flow of the electronic circuit. In the preferred embodiment of the invention shown in Figures 1 and 2, a pair of gate electrodes (201) are connected to the source and drain electrodes, respectively. A voltage is applied to the gate (201), which is insulated from the rest of the electronic circuit by being embedded in the base layer (101). The applied gate voltage applies an electric field into the electronic circuit, resulting in the attraction or repulsion of charge carriers relative to the region between the source and drain embedded in the interlayer dielectric (102). The density of charge affects the conductivity between the source and drain, which controls the flow of current in electronic circuits. As shown in Figures 1 and 2, contact elements (203) are used to connect the gate (201) to either of the metals (204) and the source and drain regions (202) into the metal (204) any of the . The different metal layers are connected by vias (205).

The monolithic integrated device described herein is characterized by a shared metal (204) between the electronic circuit and the acoustic element. This sharing is made possible by using two metals (204) from two different metal layers as the top and bottom electrodes of the acoustic element. The piezoelectric body (301) is sandwiched between the top and bottom electrodes within the interlayer dielectric (102). Thus, unlike conventional monolithic integrated devices, the acoustic element is not formed on top of the electronic circuit, but embedded within the interlayer dielectric (102). The top electrode is metal (204) in the upper metal layer and the bottom electrode is metal (204) in the lower metal layer. Furthermore, although the acoustic element uses the metal (204) of the electronic circuit as electrodes, the element structure and configuration of this monolithic integrated device allows the acoustic element to function as a passive element when the acoustic element is electronically disconnected from the active electronic circuit.

A passivation layer (103) that acts as a protective layer for the electronic circuit and piezoelectric body (301) is optionally formed on the interlayer dielectric (102). Conventionally, acoustic elements are built on top of the passivation layer (103). By using the metal (204) of the electronic circuit as the electrodes of the acoustic element The components are embedded in an interlayer dielectric (102), enabling integration of the acoustic components with electronic circuits even without a passivation layer (103). The device is formed using at least one bond-pad opening (104) extending through the passivation layer (103) and partially into the interlayer dielectric (102) until reaching one of the plurality of metals (204). , and the metal (204) is used as the pad for the monolithic integrated device. Preferably, these bond pad openings (104) are etched into the passivation layer (103) and the interlayer dielectric (102) to expose the bond pads.

One of the main features of the present invention is its structure capable of conducting surface acoustic waves or bulk acoustic waves. Figure 1 shows the structure of a monolithic integrated device that allows the acoustic element to conduct surface acoustic waves, while Figure 2 shows the structure of a monolithic integrated device that can be used to conduct surface acoustic waves or bulk acoustic waves. In Fig. 1, no cavities for vibration of the piezoelectric body (301) are formed above and below the electrodes. Therefore, the acoustic element in the monolithic integrated device shown in FIG. 1 conducts surface acoustic waves. On the other hand, the interlayer dielectric (102) in Figure 2 is formed with a top cavity (105) above the top electrode and a bottom cavity (106) below the bottom electrode. These cavities (105, 106) provide space for the vibration of the piezoelectric body, allowing the piezoelectric body to conduct bulk or surface acoustic waves.

While the present invention has been described and illustrated in detail, it is to be understood that the present invention has been presented by way of illustration and example, and not limitation. The spirit and scope of the present invention are limited only by those defined by the appended claims.

101: Substrate layer

102: Interlayer dielectric

103: Passivation layer

104: Bond pad opening

105: cavity

106: Cavity

201: Gate

202: Source and drain regions

203: Contact element

204: Metal

205: Through hole

301: Piezoelectric

Claims (8)

A monolithic integrated device, comprising: a base layer (101), which is the base of the monolithic integrated device; an interlayer dielectric (102) arranged on top of the base layer (101); an electronic circuit, basically Formed in the interlayer dielectric (102) and supported by the base layer (101), the electronic circuit includes a plurality of metal layers formed from two or more spaced apart metals (204); a passivation layer ( 103) formed on top of the interlayer dielectric (102); and a piezoelectric body (301) sandwiched between a top electrode and a bottom electrode within the interlayer dielectric (102), The top electrode located near the passivation layer (103) is metal (204) belonging to the upper metal layer of the electronic circuit and the bottom electrode is metal (204) belonging to the lower metal layer of the electronic circuit; wherein the monolithic The body device is formed with bond pad openings (104) extending through the passivation layer (103) and partially into the interlayer dielectric (102) until the bond pad openings (104) ) to one of the metals (204) of the electronic circuit, which serve as the top electrode and a pad. The monolithic integrated device of claim 1, wherein the interlayer dielectric (102) is formed with a top cavity (105) above the top electrode and a bottom cavity (106) below the bottom electrode ). The monolithic integrated device of claim 1, wherein the electronic circuit comprises at least one gate (201) in the base layer (101). The monolithic integrated device of claim 3, wherein the electronic circuit comprises at least one source and drain region (202) in the interlayer dielectric (102), the source and drain regions (202) There is a source and a drain connected to the gate (201), respectively. The monolithic integrated device of claim 4, wherein the electronic circuit includes means for connecting any one or combination of the source and drain regions (202) and the gate (201) to the plurality of A contact element (203) of one of the metals (204). The monolithic integrated device of claim 1, further comprising one or more through holes (205) for connecting different metal layers. The single-chip integrated device of claim 1, wherein the electronic circuit is a CMOS device. A monolithic integrated device, comprising: a base layer (101), which is the base of the monolithic integrated device; an interlayer dielectric (102) disposed on top of the base layer (101); a passivation layer (103) ), disposed on top of the interlayer dielectric (102); an electronic circuit formed substantially in the interlayer dielectric (102) and supported by the base layer (101), the electronic circuit comprising two A plurality of metal layers formed of one or more spaced-apart metals (204); and a piezoelectric body (301) sandwiched between a top electrode and a bottom electrode within the interlayer dielectric (102) , the top electrode located near the passivation layer (103) is metal (204) belonging to the upper metal layer of the electronic circuit and the bottom electrode is metal (204) belonging to the lower metal layer of the electronic circuit; wherein the interlayer The cell (102) is formed with a top cavity (105) above the top electrode and a bottom cavity (106) below the bottom electrode, and the monolithic integrated device is formed with at least one connection. bond pad opening (104) extending through the passivation layer (103) and partially into the interlayer dielectric (102) until the bond pad opening (104) reaches the electronic One of a plurality of metals (204) of the circuit that serves as the top electrode and a pad.

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