CN1970172A - Capacitive ultrasonic transducer device and manufacturing method thereof - Google Patents

Abstract

A capacitive ultrasonic transducer comprises a first electrode; an insulating layer formed on the first electrode; at least one supporting frame formed on the insulating layer; and a second electrode formed to be spaced apart from the first electrode, wherein the first electrode and the second electrode define an effective oscillation area of the capacitive ultrasonic transducer, and respective lengths of the first electrode and the second electrode defining the effective oscillation area are substantially the same.

Description

Capacitive ultrasonic transducer device and manufacturing method thereof

technical field

The invention relates to an ultrasonic transducer device, in particular to a capacitive ultrasonic transducer device and a manufacturing method thereof.

Background technique

With the advantages of non-invasive evaluation, real-time response and portability, ultrasonic sensing devices have been widely used in medical, military and aviation industries. For example, echographic systems or ultrasound imaging systems can obtain information from surrounding devices or from the human body based on the use of elastic waves at ultrasound frequencies. In an ultrasonic sensing device, the ultrasonic transducer is usually one of many important components. Most known ultrasonic transducers are realized by using piezoelectric ceramics. Since the acoustic impedance of piezoelectric ceramics has the same magnitude as that of solid materials, piezoelectric transducer devices are generally used to obtain information from solid materials. However, piezoelectric transducing devices are not ideal for obtaining information from liquids due to the significant impedance mismatch between piezoelectric ceramics and liquids such as human tissue. Piezoelectric transducers generally operate in the frequency band from 50KHz (kilohertz) to 200KHz. Additionally, piezoelectric transducers are typically fabricated in high temperature processes and are not ideal for integration with electronic circuits. In contrast, capacitive ultrasonic transducers can be mass-produced through standard integrated circuit (IC) processes, and thus can be integrated with IC devices. Furthermore, capacitive ultrasonic transducers are capable of operating at a higher frequency band from 200 KHz to 5 MHz (megahertz) compared to known piezoelectric transducers. Therefore, capacitive ultrasonic transducers have gradually replaced piezoelectric transducers.

FIG. 1 is a schematic cross-sectional view of a capacitive ultrasonic transducer 10 . Referring to FIG. 1 , the capacitive ultrasonic transducer 10 includes a first electrode 11 , a second electrode 12 formed on a film layer 13 , an isolation layer 14 formed on the first electrode, and a supporting sidewall 15 . The machine chamber 16 is defined by the first electrode 11 , the film layer 13 and the supporting sidewall 15 . When an appropriate AC or DC voltage is applied between the first electrode 11 and the second electrode 12, the electrostatic force causes the membrane layer 13 to vibrate and generate sound waves. The effective oscillation region of the known transducer device 10 is the region defined by the first electrode 11 and the second electrode 12 . In this example, since the second electrode 12 is shorter than the first electrode 11 , the effective oscillation area is limited by the length of the second electrode 12 . Furthermore, the film layer 13 is typically fabricated in a high temperature process such as known chemical vapor deposition (CVD) or low pressure chemical vapor deposition (LPCVD) at a temperature ranging from about 400°C to 800°C.

2A to 2D are cross-sectional views illustrating a known method for manufacturing a capacitive ultrasonic transducer. Referring to FIG. 2A, a silicon substrate 21, which is highly doped with impurities, is provided as an electrode. Next, the first nitride layer 22 and the amorphous silicon layer 23 are continuously formed on the silicon substrate 21 . The first nitride layer 22 is used to protect the silicon substrate 21 . The amorphous silicon layer 23 is used as a sacrificial layer and will be removed in subsequent processes.

Referring to FIG. 2B, the amorphous silicon layer 23 is patterned and etched to expose a portion of the first nitride layer 22 to form a patterned amorphous silicon layer 23'. A second nitride layer 24 is then formed on the patterned sacrificial layer 23', and fills up the above-mentioned exposed portions.

2C, by patterning and etching the second nitride layer 24 to form a patterned second nitride layer 24' having openings 25, thereby exposing the patterned nitride layer through the openings 25. part of the amorphous silicon layer 23'. The patterned amorphous silicon layer 23' is then removed by selective etching.

Referring to FIG. 2D , a silicon oxide layer is deposited through opening 25 to form plug 26 . Thus, a chamber 27 may be defined by the plug 26, the patterned second nitride layer 24' A metal layer 28 is then formed on the patterned second nitride layer 24' as a second electrode.

In addition, known capacitive ultrasonic transducers generally include silicon substrates. Known methods for manufacturing these capacitive ultrasonic transducers described above may utilize bulk micromachining or surface micromachining in high temperature processes, which would disadvantageously lead to high residual stresses, or would lead to the capacitive ultrasonic Deformation of the membrane of the transducer. To relieve the residual stress, an additional process such as annealing may be required, which means longer processing time and higher manufacturing cost.

In addition, the chambers, or cavities, in conventional capacitive ultrasonic transducers are usually formed by elements of different materials with different coefficients of thermal expansion, which affects the performance of the transducer. At the same time, when the transducer device is assembled in the protective cover during the packaging process, the film of the known capacitive ultrasonic transducer device will be damaged. It would be desirable to have an improved capacitive ultrasonic transducer and method of making the same.

Contents of the invention

The present invention is directed to a capacitive ultrasonic transducer and method of manufacturing the same that alleviates one or more problems due to limitations and disadvantages of the prior art.

According to one embodiment of the present invention, there is provided a capacitive ultrasonic transducer, which includes a conductive substrate; an insulating layer formed on the conductive substrate; a supporting frame formed on the insulating layer; and a conductive layer, It has substantially the same coefficient of thermal expansion as the support frame, being separated from the conductive substrate by the support frame.

In an embodiment, the support frame and the conductive layer are made of substantially the same material.

In another embodiment, the supporting frame and the conductive layer comprise a material selected from one of nickel (Ni), nickel-cobalt (NiCo), nickel-iron (NiFe) and nickel-manganese (NiMn).

And according to the present invention, there is provided a capacitive ultrasonic transducer, which includes a first electrode; an insulating layer formed on the first electrode; at least a supporting frame formed on the insulating layer; and a second electrode , which is formed to be separated from the first electrode, wherein the first electrode and the second electrode define the effective oscillation region of the capacitive ultrasonic transducer, and the first electrode and the second electrode defining the effective oscillation region The individual lengths are substantially the same.

Also according to the present invention, a capacitive ultrasonic transducer is provided, which includes a substrate; a support frame, which is formed on the substrate; and a conductive layer, which is held by the support frame on the substrate, so that the The conductive layer, the support frame and the base plate define a machine room.

Further according to the present invention, there is provided a method for manufacturing a capacitive ultrasonic transducer, which includes providing a substrate; forming an insulating layer on the substrate; forming a patterned first metal layer on the insulating layer; forming a patterned second metal layer substantially coplanar with the patterned first metal layer; a patterned metal layer formed on the patterned first metal layer and the patterned second metal layer exposing portions of the patterned first metal layer through the openings; and removing the patterned first metal layer through the openings.

Also according to the present invention, there is provided a method for manufacturing a capacitive ultrasonic transducer, comprising providing a substrate; forming an insulating layer on the substrate; forming a patterned first metal layer on the insulating layer; forming a second metal layer on the patterned first metal layer; patterning the second metal layer to expose portions of the patterned first metal layer through openings; and removing the patterned through the openings oxidized first metal layer.

Also according to the present invention, there is provided a method for manufacturing a capacitive ultrasonic transducer, which includes providing a substrate; forming an insulating layer on the substrate; forming a metal layer on the insulating layer; forming a patterned a photoresist layer; exposing a portion of the metal layer; forming a patterned first metal layer substantially coplanar with the patterned photoresist layer; removing the patterned photoresist layer; forming a patterned second metal layer that is substantially coplanar with the patterned first metal layer; formed on the patterned first metal layer and the patterned second metal layer a patterned third metal layer; exposing portions of the patterned first metal layer through openings; and removing the patterned first metal layer and portions of the metal layer through the openings.

Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will be learned from the description, or may be learned by practice of the invention. The features and advantages of the invention will be realized and attained by means of the elements and combinations particularly recited in the claims.

It should be understood that both the foregoing general description and the following detailed description are by way of illustration and explanation only, and are not restrictive of the invention claimed herein.

Description of drawings

The foregoing abstract, together with the foregoing detailed description, of the present invention may be better understood when read in conjunction with the accompanying drawings. For the purpose of illustrating the present invention, presently preferred specific embodiments are described in the drawings. It should be understood, however, that the invention is not limited to the precise arrangements and instrumentalities described.

In the attached picture:

Fig. 1 is a schematic sectional view of a known capacitive ultrasonic transducer;

2A to 2D are cross-sectional views illustrating a known method for manufacturing a capacitive ultrasonic transducer;

3A is a schematic cross-sectional view of a capacitive ultrasonic transducer device according to an embodiment of the present invention;

3B is a schematic cross-sectional view of a capacitive ultrasonic transducer according to another embodiment of the present invention;

4A to 4G are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention;

4D-1 and 4E-1 are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention;

5A to 5G are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer according to another embodiment of the present invention;

5D-1 and 5E-1 are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention;

6A to 6D are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer according to another embodiment of the present invention;

Fig. 7 is a schematic cross-sectional view of a capacitive ultrasonic transducer device according to another embodiment of the present invention;

8A is a schematic cross-sectional view illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention; and

8B is a schematic cross-sectional view illustrating a method for manufacturing a capacitive ultrasonic transducer according to another embodiment of the present invention.

Description of main components

10 Capacitive ultrasonic transducer

11 The first electrode

12 Second electrode

13 film layer

14 Isolation layer

15 Support side wall

16 machine room

21 Silicon substrate

22 The first nitride layer

23 Amorphous silicon layer

23’ patterned silicon layer

24 Second nitride layer

24’ patterned second nitride layer

25 openings

26 Embolus

27 Machine Room

28 metal layer

30 Capacitive ultrasonic transducer

31 Substrate

32 Insulation layer

33 seed layer

35 Conductive layer

36 bumps

37 Machine room

37-1 Machine Room

38 Insulation layer

38-1 Support frame

39 Capacitive ultrasonic transducer

40 Substrate

41 Insulation layer

42 patterned photoresist layer

43 sacrificial metal layer

44 metal layer

44-1 Patterned metal layer

44-2 Patterned metal layer

44-3 Part 1

44-4 Part II

45 Conductive layer

45-1 Patterned conductive layer

46 bump

46-1 bump

47 opening

48 machine room

48-1 Machine Room

49 patterned metal layer

51 seed layer

51-1 Patterned seed layer

58 Machine room

60 Substrate

61 Insulation layer

62 seed layer

63 Patterned photoresist layer

64 Patterned metal layer

64-1 Patterned metal layer

65 Patterned sacrificial layer

66 Conductive layer

67 bump

70 Capacitive ultrasonic transducer

72 Patterned insulating layer

77 Machine room

77-1 engine room

77-2 engine room

81 Patterned insulating layer

82 Patterned insulating layer

Detailed ways

Reference will now be made in detail to specific embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to represent the same or like parts.

FIG. 3A is a schematic cross-sectional view of a capacitive ultrasonic transducer device 30 according to an embodiment of the present invention. Referring to FIG. 3A , the capacitive ultrasonic transducer device 30 includes a substrate 31 , an insulating layer 32 , a supporting frame 38 and a conductive layer 35 . In an embodiment, the substrate 31 may have a thickness of about 525 μm and be formed from a silicon wafer densely doped with phosphorous to a resistance level of about 0.1 to 0.4 microohms per square centimeter (μΩ/cm2). In another aspect, the substrate 31 is a metal substrate made of aluminum (Al) or copper (Cu). The substrate 31 is used as the lower or first electrode of the capacitive ultrasonic transducer 30 . The insulating layer 32 includes a material selected from one of oxide, nitride or oxynitride. In an embodiment in accordance with the invention, the insulating layer 32 comprises silicon dioxide (SiO2) having a thickness of about 0.2 microns (μm). The support frame 38 includes a material selected from one of nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe) and nickel manganese (NiMn). In an embodiment, the support frame 38 contains a nickel layer having a thickness of about 0.5 to 10 μm. The conductive layer 35 separated from the substrate 31 by the insulating layer 32 and the supporting frame 38 is used as an oscillating film, and also serves as the upper or second electrode of the capacitive ultrasonic transducer 30 . The conductive layer 35 contains a material selected from nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe), and nickel manganese (NiMn). In an embodiment, the conductive layer 35 comprises a nickel layer having a thickness in the range of about 0.5 to 5 μm.

The sealed or unsealed machine chamber 37 is defined by the insulating layer 32 , the support frame 38 and the conductive layer 35 . Therefore, the effective oscillation region of the transducer device 30 can be defined by the substrate 31 and the conductive layer 35 . Since the individual lengths of the substrate 31 and the conductive layer 35 defining the machine chamber 37 are substantially equal, that is, the entire length of the machine chamber 37 is extended, the effective oscillation region of the transducer device 30 is shown in a larger representation than that shown in FIG. 1 The known capacitive transducing device has increased, and thus represents an increase in performance of the transducing device 30 over known capacitive transducing devices.

Referring again to FIG. 3A , the capacitive ultrasonic transducer 30 may further include at least one bump 36 formed on the conductive layer 35 and placed on the supporting frame 38 . The bump 36 can be used to protect the conductive layer 35 from damage or accidental vibration. The bump 36 may be formed of a material selected from nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe), and nickel manganese (NiMn). In an embodiment, the bump 36 contains a nickel layer having a thickness of about 5 to 50 μm. In another embodiment, the supporting frame 38 and the conductive layer 35 are made of substantially the same material, which alleviates the problem of different thermal expansion coefficients that may occur in conventional capacitive transducers.

Fig. 3B is a schematic cross-sectional view of a capacitive ultrasonic transducer device 39 according to another embodiment of the present invention. Referring to FIG. 3B , the capacitive ultrasonic transducer 39 has a structure similar to that of the capacitive ultrasonic transducer 30 described in FIG. 3A , except that the support frame 38 - 1 contains the seed layer 33 . The seed layer 33 is formed on the insulating layer 32 to facilitate metal interconnection in processes such as electrochemical deposition or electrochemical plating. The seed layer 33 contains a material selected from titanium (Ti), copper (Cu), nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe), and nickel manganese (NiMn). In an embodiment, the seed layer 33 contains a nickel layer having a thickness of about 0.15 to 0.3 μm. A sealed or unsealed machine room 37 - 1 can be defined by the insulating layer 32 , the supporting frame 38 - 1 and the conductive layer 35 .

4A to 4G are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention. Referring to FIG. 4A , a substrate 40 is provided, which is used as a common first electrode of the capacitive ultrasonic transducer device under fabrication. The substrate 40 includes a doped silicon substrate and a metal substrate. The insulating layer 41 for protecting the substrate 40 is formed on the substrate 40 by a chemical vapor deposition (CVD) process or other suitable processes. The insulating layer 41 contains oxide, nitride or oxynitride. Next, a patterned photoresist layer 42 such as PMMA (polymethylmethacry) or SU-8 is formed on the insulating layer 41 to expose a portion of the insulating layer 41 .

Referring to FIG. 4B, a sacrificial metal layer 43 is formed on the patterned surface by, for example, sputtering, evaporation, or plasma enhanced CVD (PECVD) process, followed by grinding or chemical mechanical polishing (CMP) process or other suitable process. on the photoresist layer 42. The sacrificial metal layer 43 is substantially coplanar with the patterned photoresist layer 42 and will be removed in a subsequent process. In an embodiment according to the present invention, the sacrificial metal layer 43 contains copper (Cu).

Referring to FIG. 4C , the patterned photoresist layer 42 is stripped, and a metal layer 44 is formed on the sacrificial metal layer 43 .

Referring to FIG. 4D, the metal layer 44 as described in FIG. 4C is ground or polished by a grinding process or a CMP process, so that a patterned metal layer 44-1 substantially coplanar with the sacrificial metal layer 43 can be obtained. . The patterned metal layer 44-1 then becomes a supporting frame of the capacitive ultrasonic transducer. Next, a conductive layer 45 is formed on the patterned metal layer 44 - 1 and the sacrificial metal layer 43 by sputtering, evaporation or PECVD process. In an embodiment, the patterned metal layer 44-1 and the conductive layer 45 are substantially selected from nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe) and nickel manganese (NiMn), etc. Formed from one of the same materials. Second, bumps 46 may be formed by forming a metal layer using a sputtering, evaporation, or PECVD process followed by a patterning and etching process. In an embodiment, the bump 46 is formed of a material selected from nickel (Ni), nickel-cobalt (NiCo), nickel-iron (NiFe), and nickel-manganese (NiMn).

Referring to FIG. 4E , a patterned conductive layer 45 - 1 is formed by patterning and etching the conductive layer 45 as described in FIG. 4D , thereby exposing a portion of the sacrificial metal layer 43 through the opening 47 . The patterned conductive layer 45-1 then becomes the vibrating thin film of the capacitive ultrasonic transducer, and is also the second electrode.

Referring to FIG. 4F, the sacrificial metal layer 43 described in FIG. 4E is removed through an etching process. In an embodiment, iron trichloride (FeCl3) can be used as an etching solution to remove the sacrificial metal layer 43 through a wet etching process. Since it has etching selectivity, the sacrificial metal layer 43 can be removed without significant The insulating layer 41 is removed. Therefore, the machine chamber 48 can be defined by the patterned conductive layer 45 - 1 , the patterned metal layer 44 - 1 and the insulating layer 41 , but is not sealed.

Referring to FIG. 4G , another patterned metal layer 49 may be formed by, for example, sputtering, evaporation, PECVD, or other suitable process with desired step coverage, to fill the opening 47 described in FIG. 4E . Therefore, the machine chamber 48 - 1 can be defined and sealed by the patterned conductive layer 45 - 1 , the patterned metal layer 44 - 1 , the insulating layer 41 and the patterned metal layer 49 .

4D-1 to 4E-1 are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention. Referring to FIG. 4D-1, and comparing with FIG. 4D, after the metal layer 44 is formed on the sacrificial metal layer 43, the metal layer 44 will not be reduced to the same size as the sacrificial metal layer due to grinding or polishing. Layers 43 are substantially of the same thickness. Instead, a patterned metal layer 44 - 2 may be formed to cover the sacrificial metal layer 43 . Next, bumps 46-1 are formed on the patterned metal layer 44-2.

Referring to FIG. 4E-1, and for comparison with FIG. 4E, the patterned metal layer 44-2 described in FIG. and the patterned metal layer (not numbered) of the second portion 44 - 4 , thereby exposing a portion of the sacrificial metal layer 43 through the opening 47 . The first part 44-3 and the second part 44-4 of the patterned metal layer will then become the supporting frame and the vibrating membrane of the capacitive ultrasonic transducer device respectively.

5A to 5G are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer according to another embodiment of the present invention. The method described in FIGS. 5A to 5D is similar to the method described in FIGS. 4A to 4G except that an additional seed layer 51 is formed. Referring to FIG. 5A , the substrate 40 is provided, and the insulating layer 41 is formed on the substrate 40 . Then, the seed layer 51 is formed on the insulating layer 41 by sputtering, evaporation or PECVD process. In an embodiment according to the present invention, the seed layer 51 contains titanium (Ti), copper (Cu), nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe) and nickel manganese (NiMn) etc. A selected material. Next, the patterned photoresist layer 42 is formed on the seed layer 51 to expose a portion of the seed layer 51 .

Referring to FIG. 5B , a sacrificial metal layer 43 is formed on the patterned photoresist layer 42 by, for example, an electrochemical deposition process, an electrochemical plating process, or other suitable process, followed by a grinding process or a CMP process.

Referring to FIG. 5C , the patterned photoresist layer 42 is stripped, and the metal layer 44 is formed on the sacrificial metal layer 43 by, for example, an electrochemical deposition process, an electrochemical plating process or other suitable processes.

Referring to FIG. 5D, the metal layer 44 as described in FIG. 5C is ground or polished by a grinding process or a CMP process, so that a patterned metal layer 44-1 substantially coplanar with the sacrificial metal layer 43 can be obtained. . Next, the conductive layer 45 is formed on the patterned metal layer 44 - 1 and the sacrificial metal layer 43 through an electrochemical deposition process, an electrochemical plating process or other appropriate processes. In an embodiment, the seed layer 51, the patterned metal layer 44-1 and the conductive layer 45 contain nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe) and nickel manganese (NiMn) etc. A substantially identical material selected from among. Next, bumps 46 disposed on the patterned metal layer 44-1 may be formed by forming a metal layer using a sputtering, evaporation, or PEVCD process, followed by a patterning and etching process.

Referring to FIG. 5E , for example, the conductive layer 45 described in FIG. 5D is patterned and etched to form a patterned conductive layer 45 - 1 , thereby exposing a portion of the sacrificial metal layer 43 through the opening 47 . The patterned conductive layer 45-1 then becomes the vibrating thin film of the capacitive ultrasonic transducer, and is also the second electrode.

Referring to FIG. 5F , the sacrificial metal layer 43 and portions of the seed layer 51 described in FIG. 5E may be removed by an etching process. In an embodiment, ferric chloride (FeCl3) can be used as an etching solution, which has etching selectivity, and the sacrificial metal layer 43 and part of the seed layer 51 are removed by a wet etching process. The patterned metal layer 44-1 and the patterned seed layer 51-1 together become the supporting frame of the capacitive ultrasonic transducer device. Chamber 58 can thus be defined by the patterned conductive layer 45 - 1 , the patterned metal layer 44 - 1 , the patterned seed layer 51 - 1 and the insulating layer 41 , but is not sealed.

Referring to FIG. 5G , another patterned metal layer 49 may be formed to fill the opening 47 described in FIG. 5E by, for example, an electrochemical deposition process, an electrochemical plating process, or other suitable process with desired step coverage. Thus can be defined by the patterned conductive layer 45-1, the patterned metal layer 44-1, the patterned seed layer 51-1, the insulating layer 41 and the further patterned metal layer 49 The engine room 58-1 is sealed.

5D-1 to 5E-1 are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention. Referring to FIG. 5D-1 and comparing it with FIG. 5D, after forming the sacrificial layer 43 on the seed layer 51 and forming the metal layer 44 on the sacrificial metal layer 43, the metal layer 44 will not be affected by the grinding process. or polishing process to be reduced to substantially the same thickness as the sacrificial metal layer 43 . Instead, a patterned metal layer 44 - 2 may be formed to cover the sacrificial metal layer 43 . Next, bumps 46-1 are formed on the patterned metal layer 44-2.

Referring to FIG. 5E-1 , and for comparison with FIG. 5E , the patterned metal layer 44-2 described in FIG. 5D-1 can be patterned and etched, for example, to form an and the patterned metal layer (not numbered) of the second portion 44 - 4 , thereby exposing a portion of the sacrificial metal layer 43 through the opening 47 . The first part 44-3 and the second part 44-4 of the patterned metal layer will then become the supporting frame and the vibrating membrane of the capacitive ultrasonic transducer device respectively.

6A to 6D are schematic cross-sectional views illustrating a method for manufacturing a capacitive ultrasonic transducer according to another embodiment of the present invention. Referring to FIG. 6A , a substrate 60 is provided and an insulating layer 61 is formed on the substrate 60 . Then, a seed layer 62 is formed on the insulating layer 61 by sputtering, evaporation or PECVD process. Next, a patterned photoresist layer 63 is formed on the seed layer 62 to expose a portion of the seed layer 62 . The patterned photoresist layer 63 defines the chamber of the capacitive ultrasonic transducer device under manufacture.

Referring to FIG. 6B , a patterned metal layer 64 is formed on the patterned photoresist layer 63 by, for example, an electrochemical deposition process, an electrochemical plating process, or other suitable process, followed by a grinding process or a CMP process.

Referring to FIG. 6C, the patterned photoresist layer 63 is stripped, and by, for example, an electrochemical deposition process, an electrochemical plating process, or other suitable processes, followed by grinding or CMP, the patterned A patterned sacrificial layer 65 is formed on the metal layer 64 . The patterned sacrificial layer 65 is substantially coplanar with the patterned metal layer 64 .

Referring to FIG. 6D , a conductive layer 66 is formed on the patterned metal layer 64 and the patterned sacrificial metal layer 65 by electrochemical deposition process, electrochemical plating process or other suitable processes. In an embodiment, the seed layer 62, the patterned metal layer 64 and the conductive layer 66 contain nickel (Ni), nickel cobalt (NiCo), nickel iron (NiFe) and nickel manganese (NiMn) etc. A selected one of substantially the same material. Next, bumps 67 placed on the patterned metal layer 64 are formed.

The structure shown in FIG. 6D is substantially the same as that described in FIG. 5D. The necessary steps to form an unsealed chamber as described in FIG. 5F, or to form a sealed chamber as described in FIG. 5G, are substantially the same as described through FIGS. 5E, 5F and 5G, and thus It will not be repeated here.

Fig. 7 is a schematic cross-sectional view of a capacitive ultrasonic transducer device 70 according to another embodiment of the present invention. 7A, the capacitive ultrasonic transducer 70 comprises a structure similar to the capacitive ultrasonic transducer 30 described in FIG. 3A, except for a patterned insulating layer 72, which is formed on the support frame 38 and the substrate 31. A sealed or unsealed cabinet 77 can be defined by the substrate 31 , the patterned insulating layer 72 , the support frame 38 and the conductive layer 35 .

FIG. 8A is a schematic cross-sectional view illustrating a method for manufacturing a capacitive ultrasonic transducer device according to an embodiment of the present invention. Referring to FIG. 8A, and also referring to FIG. 4F, after the sacrificial metal layer 43 (as shown in FIG. 4E) has been removed, the exposed insulating layer 43 can thus be exposed through the opening 47 by a known wet etching process or other suitable process. Partial removal of layer 41 (FIG. 4F). The wet etch process is etch-selective and thus can remove exposed portions of the insulating layer 41 without significantly removing the substrate 40, resulting in formation between the substrate 40 and the patterned metal layer 44-1. The patterned insulating layer 81 between them will then become the support frame. Therefore, the cabinet 77-1 can be defined by the substrate 40, the patterned insulating layer 81, the patterned metal layer 44-1, and the patterned conductive layer 45-1, but is not sealed. The chambers 77-1 may be sealed by a process similar to that described with reference to Figure 4G. Each in-fabrication capacitive ultrasonic transducing device includes a final structure similar to the capacitive ultrasonic transducing device 70 described in FIG. 7 .

8B is a schematic cross-sectional view illustrating a method for manufacturing a capacitive ultrasonic transducer according to another embodiment of the present invention. Referring to FIG. 8B and also referring to FIG. 5F, after the sacrificial metal layer 43 (as shown in FIG. 5E ) and the seed layer 51 (as shown in FIG. 5E ) are partially removed, a known wet etching process or In other suitable processes, the exposed portion of insulating layer 41 ( FIG. 4F ) is removed through opening 47 . A patterned insulating layer 82 is formed between the substrate 40 and the patterned metal seed layer 51 - 1 , which then becomes a supporting frame together with the patterned metal layer 44 - 1 . Therefore, the substrate can be defined by the substrate 40, the patterned insulating layer 82, the patterned metal seed layer 51-1, the patterned metal layer 44-1 and the patterned conductive layer 45-1. Engine room 77-2, but not sealed. The chambers 77-2 may be sealed by a process similar to that described with reference to Figure 5G. Each in-fabrication capacitive ultrasonic transducing device includes a final structure similar to the capacitive ultrasonic transducing device 70 described in FIG. 7 .

Those skilled in the art should immediately appreciate that changes can be made to the specific embodiments described above without departing from the broad inventive concepts thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications which fall within the spirit and scope of the present invention as defined by the claims.

In addition, in describing representative embodiments of the present invention, the specification may represent the method and/or process of the present invention as a specific sequence of steps; however, since the scope of the method or process is not limited by the Since no particular order of steps is used, the method or process should not be limited to the particular order of steps described. Those skilled in the art will appreciate that other sequences of steps are possible. Therefore, the specific order of steps presented in this specification should not be considered as limitations on the claims. In addition, the claims related to the method and/or process of the present invention should not be limited only to the implementation of the sequence of steps described in writing. It is easy for those skilled in the art to understand that the above-mentioned sequence can also be changed, and still fall within the spirit and scope of the present invention.

Claims (40)

1. A capacitive ultrasonic transducer, characterized in that it comprises: conductive substrate; an insulating layer formed on the conductive substrate; a support frame formed on the insulating layer; and The conductive layer, separated from the conductive substrate by the support frame, has substantially the same coefficient of thermal expansion as the support frame. 2. The capacitive ultrasonic transducer device according to claim 1, characterized in that the support frame is composed of nickel (Ni), nickel-cobalt (NiCo), nickel-iron (NiFe) and nickel-manganese (NiMn) etc. One of the selected materials. 3. The capacitive ultrasonic transducer device according to claim 1, characterized in that the conductive layer is composed of nickel (Ni), nickel-cobalt (NiCo), nickel-iron (NiFe) and nickel-manganese (NiMn), etc. One of the selected materials. 4. The capacitive ultrasonic transducer device according to claim 1, further comprising at least one protrusion placed on the supporting frame. 5. The capacitive ultrasonic transducer according to claim 4, wherein the at least one bump comprises a material selected from one of Ni, NiCo, NiFe and NiMn. 6 . The capacitive ultrasonic transducer device according to claim 1 , wherein the supporting frame comprises a seed layer formed on the insulating layer. 7. The capacitive ultrasonic transducer device according to claim 6, characterized in that the seed layer contains a material selected from one of titanium (Ti), copper (Cu), Ni, NiCo, NiFe and NiMn, etc. s material. 8. The capacitive ultrasonic transducer device according to claim 1, wherein the supporting frame and the conductive layer are made of substantially the same material. 9. A capacitive ultrasonic transducer, comprising: first electrode; an insulating layer formed on the first electrode; at least one support frame formed on the insulating layer; and The second electrode is formed to be separated from the first electrode, wherein the first electrode and the second electrode define the effective oscillation region of the capacitive ultrasonic transducer, and the first electrode and the effective oscillation region define the effective oscillation region Individual lengths of the second electrodes are substantially the same. 10. The capacitive ultrasonic transducer according to claim 9, wherein the support frame and the second electrode are formed of substantially the same material. 11. The capacitive ultrasonic transducer device according to claim 9, further comprising at least one protrusion disposed on the at least one support frame. 12. The capacitive ultrasonic transducer according to claim 9, wherein the at least one supporting frame comprises a seed layer formed on the insulating layer. 13. A capacitive ultrasonic transducer, characterized in that it comprises: Substrate; a support frame formed on the substrate; and The conductive layer is held on the substrate by the support frame, so that the machine room can be defined by the conductive layer, the support frame and the substrate. 14. The capacitive ultrasonic transducer according to claim 13, further comprising a patterned insulating layer formed between the supporting frame and the substrate. 15. The capacitive ultrasonic transducer according to claim 14, wherein the supporting frame comprises a seed layer formed on the patterned insulating layer. 16. The capacitive ultrasonic transducer according to claim 13, wherein the individual lengths of the conductive layer and the substrate defining the chamber are substantially the same. 17. The capacitive ultrasonic transducer device according to claim 13, wherein the support frame and the conductive layer are made of substantially the same material. 18. A method for manufacturing a capacitive ultrasonic transducer, characterized in that it comprises: Provide the substrate; forming an insulating layer on the substrate; forming a patterned first metal layer on the insulating layer; forming a patterned second metal layer that is substantially coplanar with the patterned first metal layer; forming a patterned third metal layer on the patterned first metal layer and the patterned second metal layer, thereby exposing portions of the patterned first metal layer through openings; and The patterned first metal layer is removed through the openings. 19. The method according to claim 18, further comprising: forming a patterned photoresist layer on the insulating layer; and A patterned first metal layer is formed that is substantially coplanar with the patterned photoresist layer. 20. The method of claim 18, further comprising: removing the patterned first metal layer through an opening, thereby exposing a portion of the insulating layer; and Portions of this insulating layer are removed. 21. The method of claim 18, further comprising: forming a metal layer on the patterned first metal layer and the patterned second metal layer; forming a patterned fourth metal layer within the metal layer at a location corresponding to the patterned second metal layer; and The metal layer is patterned and etched to form the patterned third metal layer. 22. The method of claim 18, further comprising forming a patterned metal layer to fill the openings. 23. The method of claim 18, further comprising: forming a fourth metal layer on the insulating layer; and The patterned photoresist layer is formed on the fourth metal layer. 24. The method of claim 18, further comprising forming the patterned second metal layer and the patterned third metal layer from substantially the same material. 25. The method of claim 18, further comprising forming the patterned second metal layer, the patterned third metal layer, and the patterned fourth metal layer from substantially the same material . 26. A method for manufacturing a capacitive ultrasonic transducer, characterized by comprising: Provide the substrate; forming an insulating layer on the substrate; forming a patterned first metal layer on the insulating layer; forming a second metal layer on the patterned first metal layer; patterning the second metal layer to expose portions of the patterned first metal layer through openings; and The patterned first metal layer is removed through the openings. 27. The method of claim 26, further comprising: forming a patterned photoresist layer on the insulating layer; and A patterned first metal layer is formed that is substantially coplanar with the patterned photoresist layer. 28. The method of claim 26, further comprising: removing the patterned first metal layer through the openings, thereby exposing portions of the insulating layer; and These portions of the insulating layer are removed. 29. The method of claim 26, further comprising: forming a third metal layer on the second metal layer; and The third metal layer is patterned to form bumps on the second metal layer. 30. The method of claim 26, further comprising forming a patterned metal layer to fill the openings. 31. The method of claim 26, further comprising: forming a fourth metal layer on the insulating layer; and The patterned photoresist layer is formed on the fourth metal layer. 32. The method of claim 29, further comprising forming the second metal layer and the third metal layer from substantially the same material. 33. The method of claim 31, further comprising forming the second metal layer and the fourth metal layer from substantially the same material. 34. A method for manufacturing a capacitive ultrasonic transducer, characterized by comprising: Provide the substrate; forming an insulating layer on the substrate; forming a metal layer on the insulating layer; forming a patterned photoresist layer on the metal layer, thereby exposing portions of the metal layer; forming a patterned first metal layer that is substantially coplanar with the patterned photoresist layer; removing the patterned photoresist layer; forming a patterned second metal layer that is substantially coplanar with the patterned first metal layer; forming a patterned third metal layer on the patterned first metal layer and the patterned second metal layer, thereby exposing portions of the patterned first metal layer through openings; and The patterned first metal layer and portions of the metal layer are removed through the openings. 35. The method of claim 34, further comprising: forming a metal layer on the patterned first metal layer and the patterned second metal layer; forming a patterned fourth metal layer within the metal layer at a location corresponding to the patterned second metal layer; and The metal layer is patterned and etched to form the patterned third metal layer. 36. The method of claim 34, further comprising forming a patterned metal layer to fill the openings. 37. The method of claim 34, further comprising forming the patterned second metal layer and the patterned third metal layer from substantially the same material. 38. The method of claim 35, further comprising forming the metal layer, the patterned second metal layer, and the patterned third metal layer from substantially the same material. 39. The method of claim 34, further comprising forming a metal layer on the insulating layer with a material selected from one of Ti, Cu, Ni, NiCo, NiFe, and NiMn. 40. The method of claim 34, further comprising: removing the patterned first metal layer and portions of the metal layer through the openings, thereby exposing portions of the insulating layer; and These portions of the insulating layer are removed.

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