TWI528520B - Pressure sensor and manufacturing method of the same - Google Patents

Description

Pressure sensor and method of manufacturing same

The present disclosure relates to a pressure sensor and a method of manufacturing the same, and more particularly to a pressure sensor having a degree of deformation caused by a change in temperature and an increase in initial capacitance value, and a method of manufacturing the same.

In recent years, with the rapid development of smart phones and tablets, and the demand for anti-noise functions of smart phones, the technology development of micro-electromechanical (MEMS) microphones has become increasingly mature, and the demand for MEMS microphones continues to grow. .

MEMS microphones can be used in voice secretary, voice navigation and voice noise reduction, etc. However, noise in the phone may affect the quality of the call. Therefore, in order to reduce the background volume and thus improve the call quality, the noise suppression technology of the MEMS microphone is one of the important topics.

The disclosure relates to a pressure sensor and a method of manufacturing the same. In the pressure sensor of the embodiment, the conductive/dielectric composite structure of the second electrode layer can improve the deformation degree of the overall material caused by the temperature change, and increase the initial capacitance value of the entire component, thereby improving the reliability of the component. .

According to one embodiment of the present disclosure, a pressure sensor is proposed. The pressure sensor includes a substrate, a dielectric oxide layer, a first electrode layer, a dielectric connection layer, and a second electrode layer. The dielectric oxide layer is formed on the substrate, the first electrode layer is formed on the dielectric oxide layer, the dielectric connection layer is formed on the first electrode layer, and the second electrode layer is formed on the dielectric connection layer. The second electrode layer includes a patterned conductive layer and a dielectric layer. The patterned conductive layer has a plurality of through holes, and a dielectric layer is formed on the patterned conductive layer and covers the inner walls of the through holes. The first electrode layer, the dielectric connecting layer and the second electrode layer define a first chamber between the first electrode layer and the second electrode layer.

According to another embodiment of the present disclosure, a method of manufacturing a pressure sensor is proposed. The method of manufacturing the pressure sensor includes the following steps. Providing a substrate; forming a dielectric oxide layer on the substrate; forming a first electrode layer on the dielectric oxide layer; forming a dielectric connection layer on the first electrode layer; and forming a second electrode layer on the substrate The dielectric connecting layer comprises: forming a patterned conductive layer having a plurality of through holes; and forming a dielectric layer on the patterned conductive layer and covering the inner walls of the through holes. The first electrode layer, the dielectric connecting layer and the second electrode layer define a first chamber between the first electrode layer and the second electrode layer.

In order to better understand the above and other aspects of the present invention, the preferred embodiments are described below, and in conjunction with the drawings, the detailed description is as follows:

100, 200‧‧‧ pressure sensor

110, 110s, 110s', 210‧‧‧ substrates

110c‧‧‧ second chamber

120, 120s, 220‧‧‧ first electrode layer

120a‧‧‧First electrode layer surface

120t‧‧‧first electrode layer slotting

130‧‧‧Dielectric connection layer

130c‧‧‧ recess

130s, 143s1, 143s2‧‧‧ dielectric material layer

140, 240‧‧‧ second electrode layer

141‧‧‧ patterned conductive layer

141t‧‧‧Perforation

143‧‧‧ dielectric layer

150‧‧‧ first chamber

160‧‧‧ convex structure

170, 170s, 270‧‧ dielectric oxide layer

245‧‧‧ Sealing material

G‧‧‧ gap

FIG. 1 is a schematic diagram of a pressure sensor according to an embodiment of the disclosure.

FIG. 2 is an exploded view of a pressure sensor according to an embodiment of the present disclosure.

FIG. 3 is a schematic diagram of a pressure sensor according to another embodiment of the disclosure. Figure.

4A to 4J are schematic views showing a method of manufacturing a pressure sensor according to an embodiment of the present invention.

5A to 5D are schematic views showing a manufacturing method of a pressure sensor according to another embodiment of the present invention.

In an embodiment of the present disclosure, in the pressure sensor, the conductive/dielectric composite structure of the second electrode layer can improve the degree of deformation of the overall material caused by temperature changes, and increase the initial capacitance value of the entire component, thereby Improve the reliability of components. Embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. The same reference numerals are used to designate the same or similar parts. It is to be noted that the drawings have been simplified to illustrate the details of the embodiments, and the detailed description of the embodiments is for illustrative purposes only and is not intended to limit the scope of the disclosure. Those having ordinary knowledge may modify or change the structures as needed in accordance with the actual implementation.

FIG. 1 is a schematic diagram of a pressure sensor 100 according to an embodiment of the present disclosure. FIG. 2 is an exploded view of the pressure sensor 100 of one embodiment of the present disclosure. Please refer to pictures 1~2. The pressure sensor 100 includes a substrate 110, a first electrode layer 120, a dielectric connection layer 130, and a second electrode layer 140. The first electrode layer 120 is formed on the substrate 110, the dielectric connection layer 130 is formed on the first electrode layer 120, and the second electrode layer 140 is formed on the dielectric connection layer 130. The second electrode layer 140 includes a patterned conductive layer 141 and a dielectric layer 143. The patterned conductive layer 141 has a plurality of vias 141t formed on the patterned conductive layer 141 and packaged. The inner walls of the perforations 141t are covered. The first electrode layer 120, the dielectric connection layer 130, and the second electrode layer 140 define a first chamber 150 between the first electrode layer 120 and the second electrode layer 140.

In the embodiment, as shown in FIG. 1, the substrate 110 has a second opening 110c, and the second chamber 110c exposes the surface 120a of the first electrode layer 120. The substrate 110 is, for example, a tantalum substrate.

In the embodiment, as shown in FIG. 1, the first electrode layer 120 has a plurality of slots 120t that communicate with the first chamber 150 and the second chamber 110c. In the embodiment, as shown in Fig. 2, the surface 120a of the first electrode layer 120 is, for example, circular, and the slits 120t are interlaced, for example, in a peripheral region of the surface 120a.

In one embodiment, the pressure sensor 100 is, for example, a sound pressure sensor, such as a microelectromechanical microphone. The first electrode layer 120 is a movable member with respect to the second electrode layer 140, and the first electrode layer 120 is slotted 120t. Designed to achieve the effect of slowing and releasing material stress, thereby increasing the variation tolerance of material process stress.

In the embodiment, as shown in FIG. 1, the groove 120t is separated from the substrate by a gap G, the first electrode layer 120 is separated from the substrate by a gap G, and the second chamber 150 is not exposed. Slot 120t. In one embodiment, the pressure sensor 100 is, for example, a sound pressure sensor, and the gap G forms an acoustic resistance channel to improve the frequency response, reducing the frequency response in the case of low frequency decay, thereby causing the frequency sensed by the pressure sensor 100. The scope is more complete.

In the embodiment, the material of the dielectric connection layer 130 is different from the material of the first electrode layer 120 and the material of the second electrode layer 140. The dielectric connection layer 130 connects the first electrode layer 120 and the second electrode layer 140, thereby achieving the effect of stress balance. In the process, also due to different materials, the essential stress of the dielectric connection layer 130 and two electricity The intrinsic stress between the pole layers 120 and 140 is exactly compensated for each other.

In the embodiment, the first electrode layer 120 is made of, for example, polysilicon, and the dielectric connection layer 130 is made of, for example, yttrium oxide. In the second electrode layer 140, the patterned conductive layer 141 is made of, for example, a metal having conductivity, and the dielectric layer 143 is made of, for example, tantalum nitride (SiN). In this way, since the materials are the same as those commonly used in the CMOS process, the same material and process as the CMOS process can be applied in the front stage of the process of fabricating the pressure sensor 100, and then only in the CMOS process portion. The pressure sensor 100 can be completed by adding a simple microelectromechanical process after completion. Moreover, in the embodiment, the conductive/dielectric composite material of the second electrode layer 140 has a lower coefficient of thermal expansion (CTE) than the pure metal, thereby improving the overall material caused by temperature changes. The degree of deformation.

Furthermore, in the second electrode layer 140, as shown in FIG. 1, the dielectric layer 143 covers the patterned conductive layer 141 such that the first electrode layer 120 and the patterned conductive layer 141 are interposed except for air. Electrical material. Taking the dielectric layer 143 as a tantalum nitride layer as an example, the dielectric constant is about 7, which is higher than the dielectric constant of air (about 1), so that the initial capacitance value of the entire component can be increased, and the possibility of the component can be lowered. The resulting parasitic capacitance affects the operation and performance of the component, which in turn increases the sensitivity of the component.

In one embodiment, as shown in FIGS. 1 to 2, the through hole 141t of the patterned conductive layer 141 is communicated to the first chamber 150, and the pressure sensor 100 is an acoustic pressure sensor, and the through hole 141t is used as a sound hole. . In the embodiment, the number and distribution of the through holes 141t may be appropriately changed depending on the actual application, and are not limited to the ones shown in FIGS.

In an embodiment, as shown in FIG. 1 , the pressure sensor 100 may further include a dielectric oxide layer 170 formed between the substrate 110 and the first electrode layer 120 . The dielectric oxide layer 170 can define the location and size of the gap G.

In an embodiment, as shown in FIG. 1 , the pressure sensor 100 may further include a plurality of protrusions 160 formed on the second electrode layer 140 and located on the first electrode layer 120 and the first Between the two electrode layers 140. Referring to FIG. 2, a plurality of convex structures 160 (not shown) may be formed, for example, on the surface of the second electrode layer between the through holes 141t. In the embodiment, as shown in FIG. 1, the convex structure 160 is integrally formed with the dielectric layer 143.

The convex structure 160 reduces the area in which the upper and lower film layers (for example, the first electrode layer 120 and the second electrode layer 140) are in contact with each other in the process. For example, when the wet etching process is performed, the first electrode layer 120 and the second electrode layer 140 may be stuck together, and the first electrode layer 120 and the second electrode layer 140 are caused by the presence of the convex structure 160. At most, only the partial contact of the convex structure 160 can reduce the adhesion, so that the anti-adhesion effect of the adjacent film layer in the process can be achieved. Moreover, when the finished product is subjected to the drop test or the sound pressure is large, the film layers on both sides of the first chamber 150 (for example, the first electrode layer 120 and the second electrode layer 140) may also contact, via the convex. The structure 160 reduces the contact area of the two film layers, so that the film layers on both sides of the first chamber 150 can easily return to the original position even after contact, and can overcome the electrostatic attraction force or the condition that the Valle force exceeds the restoring force. , thereby improving the reliability of the product.

FIG. 3 is a schematic diagram of a pressure sensor 200 according to another embodiment of the disclosure. The pressure sensor 200 of the present embodiment differs from the pressure sensor 100 of the previous embodiment in the design of the substrate 210, the first electrode layer 220, the second electrode layer 240, and the dielectric oxide layer 270, and the rest are the same. Let me repeat.

In the embodiment, as shown in FIG. 3, the substrate 210 does not have any second chamber, the first electrode layer 220 does not have any slots, and the first electrode layer 220, the dielectric connection layer 130, and the second electrode layer 240 The first chamber 150 is completely closed.

In an embodiment, as shown in FIG. 3, the second electrode layer 240 may further include a sealing material 245, the sealing material 245 is filled in the through hole 141t and completely fills the through hole 141t, so that the first The electrode layer 220, the dielectric connection layer 130, and the second electrode layer 240 completely enclose the first chamber 150. In the embodiment, the sealing material 245 is, for example, an insulating sealing material, which may be an inorganic material or an organic material such as cerium oxide (SiO ₂ ) or cerium nitride (SiN) or parylene. In one embodiment, the pressure sensor 200 is, for example, an absolute pressure sensor.

The following is a method of manufacturing a pressure sensor 100 of the embodiment, which is for illustrative purposes only and is not intended to limit the invention. Those having ordinary knowledge may modify or change the steps as needed according to the actual implementation. Please refer to Figures 4A to 4J. 4A to 4J are schematic views showing a manufacturing method of a pressure sensor 100 according to an embodiment of the present invention.

Please refer to pictures 4A~4B. A substrate 110s is provided, and a first electrode layer 120 is formed on the substrate 110s. In an embodiment, before the first electrode layer 120 is formed on the substrate 110s, a dielectric oxide layer 170s may be formed on the substrate 110s to form a dielectric oxide layer 170s between the substrate 110s and the first electrode layer 120. .

The manufacturing method of forming the first electrode layer 120 includes, for example, the following steps. As shown in FIG. 4A, the first electrode layer 120s is formed on the dielectric oxide layer 170s, and then, as shown in FIG. 4B, the first electrode layer 120s is etched to form a plurality of openings. Slot 120t. The slots 120t are in communication with the first chamber and the second chamber formed in a subsequent process.

Next, referring to FIGS. 4C-4J, a dielectric connection layer 130 is formed on the first electrode layer 120, and a second electrode layer 140 is formed on the dielectric connection layer 130. The first electrode layer 120 and the dielectric connection layer are formed. The 130 and second electrode layers 140 define a first chamber 150 between the first electrode layer 120 and the second electrode layer 140.

The manufacturing method of forming the dielectric connection layer 130 and the second electrode layer 140 includes, for example, the following steps.

As shown in FIG. 4C, a dielectric material layer 130s is formed on the first electrode layer 120. In this step, a dielectric material layer 130s is also formed in the trench 120t. In the embodiment, the substrate 110s may be subjected to a thinning process to form a thinned substrate 110s'. In an embodiment, the step of thinning the substrate is used to determine the thickness of the substrate 110 in the final product, and the size of the first chamber 150 can be determined. In the examples, the substrate is thinned, for example, by grinding.

As shown in FIG. 4D, the dielectric material layer 130s is etched to form a plurality of recesses 130c. These recesses 130c are used to define the position and size of the convex structures formed in subsequent processes.

As shown in FIG. 4E, a dielectric material layer 143s1 is formed on the dielectric material layer 130s and filled with the recess 130c.

As shown in FIG. 4F, a patterned conductive layer 141 is formed on the dielectric material layer 143s1. The patterned conductive layer 141 has a plurality of vias 141t, for example, a via 141t formed by an etching process.

As shown in FIG. 4G, a dielectric material layer 143s2 is formed on the patterned conductive layer 141 and filled with the vias 141t. Dielectric material layers 143s1 and 143s2 are completely The patterned conductive layer 141 is covered. In one embodiment, the material of the dielectric material layer 143s1 and the material of the dielectric material layer 143s2 are the same.

As shown in FIG. 4H, the dielectric material layers 143s1 and 143s2 are etched according to the position of the through holes 141t to form the second electrode layer 140. In this etching step, the vias 141t extend to the contact dielectric material layer 130s. In the second electrode layer 140, the dielectric layer covers the inner wall of the through hole 141t.

As shown in FIG. 4I, the substrate 110s is etched to form the second chamber 110c, and the second chamber 110c exposes the surface 120a of the first electrode layer 120. In an embodiment, the dielectric oxide layer 170s can serve as an etch barrier when etching a substrate. After etching the substrate to form the substrate 110 having the second chamber 110c, the dielectric oxide layer 170s may be further etched to form the dielectric oxide layer 170 and the gap G between the first electrode layer 120 and the substrate 110, for example It is carried out in a wet etching process.

As shown in FIG. 4J, the dielectric material layer 130s is etched to form the dielectric connection layer 130, the first chamber 150, and the convex structure 160. For example, it is carried out in a wet etching process. Thus far, the pressure sensor 100 as shown in Fig. 4J (Fig. 1) is formed.

The following is a method of manufacturing another pressure sensor 200 of the embodiment, which is for illustrative purposes only and is not intended to limit the invention. Those having ordinary knowledge may modify or change the steps as needed according to the actual implementation. Please refer to the 4Cth to 4thth and 5A to 5D drawings at the same time. 5A to 5D are schematic views showing a manufacturing method of a pressure sensor 200 according to another embodiment of the present invention.

Please refer to Figure 5A. Providing a substrate 210 to form a dielectric oxide layer 270 is on the substrate 210, and the first electrode layer 220 is formed on the substrate 210.

Please refer to the 4C~4H and 5B drawings at the same time. The patterned conductive layer 141, the dielectric layer 143, and the through holes 141t are formed in a manner as shown in FIGS. 4C to 4H, and the through holes 141t extend to the contact dielectric material layer 130s.

Please refer to Figure 5C. The dielectric material layer 130s is etched to form the dielectric connection layer 130 and the first chamber 150. At this time, the first electrode layer 220, the dielectric connection layer 130, and the patterned conductive layer 141 and the dielectric layer 143 define the first chamber 150 between the first electrode layer 220 and the patterned conductive layer 141.

Please refer to Figure 5D. A sealing material 245 is filled in all of the through holes 141t to seal all of the through holes 141t such that the first electrode layer 220, the dielectric connecting layer 130, and the second electrode layer 240 completely close the first chamber 150. So far, the pressure sensor 200 as shown in Fig. 5D (Fig. 3) is formed.

In conclusion, the present invention has been disclosed in the above preferred embodiments, and is not intended to limit the present invention. A person skilled in the art can make various changes and modifications without departing from the spirit and scope of the invention. Therefore, the scope of the invention is defined by the scope of the appended claims.

100‧‧‧pressure sensor

110‧‧‧Substrate

110c‧‧‧ second chamber

120‧‧‧First electrode layer

120a‧‧‧First electrode layer surface

120t‧‧‧first electrode layer slotting

130‧‧‧Dielectric connection layer

140‧‧‧Second electrode layer

141‧‧‧ patterned conductive layer

141t‧‧‧Perforation

143‧‧‧ dielectric layer

150‧‧‧ first chamber

160‧‧‧ convex structure

170‧‧‧Dielectric oxide layer

G‧‧‧ gap

Claims (16)

A pressure sensor comprising: a substrate; a dielectric oxide layer formed on the substrate; a first electrode layer formed on the dielectric oxide layer; a dielectric connection layer formed on the first electrode layer And a second electrode layer formed on the dielectric connection layer, the second electrode layer comprising: a patterned conductive layer having a plurality of vias; and a dielectric layer formed on sidewalls of the patterned conductive layer An inner wall covering the perforations on the top and the bottom; wherein the first electrode layer, the dielectric connecting layer and the second electrode layer define a first chamber on the first electrode layer and the second electrode Between the layers. The pressure sensor of claim 1, wherein the substrate has a second opening that exposes a surface of the first electrode. The pressure sensor of claim 1, wherein the first electrode layer has a plurality of slots that communicate with the first chamber and the second chamber. The pressure sensor of claim 3, wherein the first electrode layer and the substrate are separated by a gap. The pressure sensor according to claim 1, wherein the material of the dielectric connecting layer is different from the material of the first electrode layer and the material of the second electrode layer. The pressure sensor of claim 1, wherein the perforations are connected to the first chamber. The pressure sensor of claim 1, further comprising a plurality of protrusions formed on the second electrode layer between the first electrode layer and the second electrode layer. The pressure sensor of claim 1, further comprising a dielectric oxide layer formed between the substrate and the first electrode layer. The pressure sensor of claim 1, wherein the second electrode layer further comprises a sealing material filled in the perforations, so that the first electrode layer and the dielectric layer The electrical connection layer and the second electrode layer completely enclose the first chamber. A method of manufacturing a pressure sensor, comprising: providing a substrate; forming a dielectric oxide layer on the substrate; forming a first electrode layer on the dielectric oxide layer; forming a dielectric connection layer thereon On the first electrode layer; Forming a second electrode layer on the dielectric connecting layer, comprising: forming a patterned conductive layer having a plurality of through holes; and forming a dielectric layer on the sidewall, the top and the bottom of the patterned conductive layer and coating The inner wall of the perforations; wherein the first electrode layer, the dielectric connecting layer and the second electrode layer define a first chamber between the first electrode layer and the second electrode layer. The method of manufacturing a pressure sensor according to claim 10, further comprising: etching the substrate to form a second chamber, the second chamber exposing a surface of the first electrode layer. The method of manufacturing the pressure sensor of claim 11, further comprising: etching the first electrode layer to form a plurality of slots, the slots connecting the first chamber and the Second chamber. The method of manufacturing a pressure sensor according to claim 10, further comprising: forming a plurality of protrusions on the second electrode and between the first electrode and the second electrode. The method for manufacturing a pressure sensor according to claim 10, further comprising: A dielectric oxide layer is formed between the substrate and the first electrode layer. The method of manufacturing a pressure sensor according to claim 14, further comprising: etching the dielectric oxide layer to form a gap between the first electrode layer and the substrate. The method of manufacturing a pressure sensor according to claim 10, further comprising: filling a sealing material in the perforations to make the first electrode layer and the dielectric connection The layer and the second electrode layer completely enclose the first chamber.