TWI882711B - Micro electro mechanical system structure and manufacturing method thereof - Google Patents

Abstract

The present disclosure provides a micro electromechanical system structure, which includes a substrate, an oxide layer, a circuit layer, and a patterned sensing layer. The oxide layer is disposed on the substrate. The circuit layer is disposed above the oxide layer. The patterned sensing layer is disposed on the circuit layer. The patterned sensing layer includes a first portion and a second portion. The first portion is disposed on the second portion, and a pattern of the second portion is different from a pattern of the first portion.

Description

Micro-electromechanical system structure and manufacturing method thereof

The present disclosure provides a micro-electromechanical system structure and a method for manufacturing the micro-electromechanical system structure.

Microelectromechanical system (MEMS) is a technology that integrates miniaturized mechanical and electromechanical components on an integrated chip. Micro-fabrication technology is usually used to manufacture MEMS devices. In recent years, MEMS devices have been widely used. For example, MEMS devices exist in mobile phones (e.g., accelerometers, gyroscopes, digital compasses), pressure sensors, microfluidic components (e.g., valves, pumps), optical switches (e.g., (reflective) mirrors), imaging devices (e.g., micromachined ultrasonic transducers (MUTs)), biosensors (e.g., MEMS-based glucose sensors), etc.

The present disclosure provides a micro-electromechanical system structure, which includes a substrate, an oxide layer, a circuit layer, and a patterned sensing layer. The oxide layer is disposed on the substrate. The circuit layer is disposed above the oxide layer. The patterned sensing layer is disposed on the circuit layer, wherein the patterned sensing layer includes a first portion and a second portion, the first portion is disposed on the second portion, and the pattern of the second portion is different from the pattern of the first portion.

According to one or more embodiments of the present disclosure, the patterned sensing layer includes titanium nitride.

According to one or more embodiments of the present disclosure, the patterned sensing layer includes a plurality of first portions protruding upward from a second portion at intervals from each other.

According to one or more embodiments of the present disclosure, the pattern of the second portion is the same as the pattern of the circuit layer.

According to one or more embodiments of the present disclosure, the MEMS structure further includes an adhesive layer disposed between the oxide layer and the circuit layer.

Another aspect of the present disclosure provides a method for manufacturing a micro-electromechanical system structure, comprising the following steps. Forming an oxide layer to cover a substrate. Forming a conductive layer to cover the oxide layer. Forming a sensing layer to cover the conductive layer, wherein the sensing layer has a second portion and a first portion located on the second portion. Patterning the first portion of the sensing layer to form a first patterned sensing layer. Patterning the second portion of the sensing layer and the conductive layer to form a second patterned sensing layer and a circuit layer, wherein the pattern of the second patterned sensing layer is different from the pattern of the first patterned sensing layer.

According to one or more embodiments of the present disclosure, the conductive layer or circuit layer includes a copper-aluminum alloy.

According to one or more embodiments of the present disclosure, the manufacturing method of the MEMS structure further includes forming an adhesion layer between the oxide layer and the conductive layer.

According to one or more embodiments of the present disclosure, the second portion of the second patterned sensing layer has the same pattern as the circuit layer.

According to one or more embodiments of the present disclosure, the manufacturing method of the micro-electromechanical system structure further includes forming a dielectric layer to cover the second patterned sensing layer and the circuit layer; forming an insulating layer on the dielectric layer; and etching the insulating layer and the dielectric layer until the three-dimensional sensing portion of the second patterned sensing layer is exposed.

10: Micro-electromechanical system structure

100:Substrate

110: Oxide layer

120: Line layer

122: Conductive layer

130: Patterned sensing layer

130a: Part 1

130b: Part 2

132: Sensing layer

132a: Part 1

132b: Part 2

140: Dielectric layer

142: Dielectric layer

150: Insulation layer

152: Insulation layer

160: Adhesive layer

162: Adhesive layer

PR1: Photoresist

PR2: Photoresist

Various aspects of the present disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It is noted that, in accordance with standard industry practice, the various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.

Figure 1 is a cross-sectional schematic diagram of a micro-electromechanical system structure according to an embodiment of the present disclosure.

Figures 2 to 7 are cross-sectional schematic diagrams of manufacturing a micro-electromechanical system structure at various stages of the manufacturing process according to an embodiment of the present disclosure.

The following will disclose multiple implementations of the present disclosure with drawings. For the sake of clarity, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present disclosure. In other words, in some implementations of the present disclosure, these practical details are not necessary. In addition, in order to simplify the drawings, some commonly used structures and components will be depicted in the drawings in a simple schematic manner.

In order to conveniently describe the relationship between an element or feature in the diagram and another element or features, spatially related terms such as "under", "below", "lower", "above", "above", "upper", "upper" and similar terms may be used. In addition to the orientation shown in the diagram, spatially related terms also cover different orientations of the device in use or operation. When the device is turned to a different orientation (for example, rotated 90 degrees or other orientations), the spatially related adjectives used therein will also be interpreted according to the orientation after the rotation.

One aspect of the present disclosure is to provide a micro-electromechanical system structure that can be applied to biosensing. FIG. 1 is a cross-sectional schematic diagram of a micro-electromechanical system structure 10 of an embodiment of the present disclosure. The micro-electromechanical system structure 10 includes a substrate 100, an oxide layer 110, a circuit layer 120, and a patterned sensing layer 130. Specifically, the oxide layer 110 is disposed on the substrate 100. In some embodiments, the substrate 100 may include a semiconductor material, such as single crystal silicon, polycrystalline silicon, amorphous silicon, SiGe, Ge, SiC, etc. In some embodiments, the oxide layer 110 includes a nitride (e.g., silicon nitride (SiN)), an oxide (e.g., silicon dioxide ( _SiO2 )), an oxynitride (e.g., silicon _oxynitride ( _SiOxNy )), other dielectric materials, or a combination of the foregoing.

Continuing with FIG. 1 , the circuit layer 120 is disposed above the oxide layer 110. In some embodiments, the circuit layer 120 includes aluminum-copper alloy (AlCu) or other suitable conductive materials.

In some embodiments, the MEMS structure 10 may further include an adhesive layer 160 disposed between the oxide layer 110 and the circuit layer 120. In some embodiments, the adhesive layer 160 includes titanium, such as a titanium layer. The titanium layer can increase the bonding between the circuit layer 120 and the oxide layer 110.

Continuing with FIG. 1 , the patterned sensing layer 130 is disposed on the circuit layer 120. It is noteworthy that the pattern of the patterned sensing layer 130 is different from the pattern of the circuit layer 120. In some embodiments, the patterned sensing layer 130 includes a metal nitride, such as titanium nitride (TiN) or other suitable sensing materials. In some embodiments, the patterned sensing layer includes a first portion 130a and a second portion 130b, the first portion 130a is located on the second portion 130b, and the pattern of the second portion 130b is different from the pattern of the first portion 130a. In some embodiments, the pattern of the second portion 130b of the patterned sensing layer 130 is the same as the pattern of the circuit layer 120. In some embodiments, a plurality of first portions 130a protrude upward from the second portion 130b, and the first portions 130a are spaced apart from each other by a specific distance. In some embodiments, the spacing distance between two adjacent first portions 130a may be about 1.0 micron to 2.0 microns, for example, about 1.1 microns, 1.2 microns, 1.3 microns, 1.4 microns, 1.5 microns, 1.6 microns, 1.7 microns, 1.8 microns, or 1.9 microns. In some embodiments, the width of each first portion 130a may be about 0.3 micron to 0.8 micron, for example, about 0.4 micron, 0.5 micron, 0.6 micron, or 0.7 micron. In some embodiments, the height of the first portion 130a is greater than the height of the second portion 130b. In some embodiments, a plurality of first portions 130a are connected to each other by a plurality of second portions 130b.

Another aspect of the present disclosure is to provide a method for manufacturing a micro-electromechanical system structure. Figures 2 to 7 are cross-sectional schematic diagrams of manufacturing a micro-electromechanical system structure 10 at various stages of the manufacturing process according to an embodiment of the present disclosure. The method for manufacturing a micro-electromechanical system structure 10 includes the following steps.

First, an oxide layer 110 is formed to cover the substrate 100, as shown in FIG2. In some embodiments, the oxide layer 110 can be formed on the substrate 100 by plasma-enhanced chemical vapor deposition (PECVD), sub-atmospheric chemical vapor deposition (SACVD), atmospheric pressure chemical vapor deposition (APCVD), high density plasma chemical vapor deposition (HDPCVD), physical vapor deposition (PVD), atomic layer deposition (ALD), thermal oxidation or other suitable methods. In some embodiments, the thickness of the oxide layer 110 is about 3500Å to 4500Å, for example, about 3600Å, 3700Å, 3800Å, 3900Å, 4000Å, 4100Å, 4200Å, 4300Å, or 4400Å.

Next, a conductive layer 122 is formed to cover the oxide layer 110, as shown in FIG. 2. In some embodiments, the conductive layer 122 may be formed on the oxide layer 110 using PVD, chemical vapor deposition (CVD), electrolytic plating, electroless plating, or other suitable methods. In some embodiments, the conductive layer 122 includes an aluminum copper alloy (AlCu) or other suitable conductive materials. In some embodiments, the thickness of the conductive layer 122 is about 3500Å to 4500Å, for example, about 3600Å, 3700Å, 3800Å, 3900Å, 4000Å, 4100Å, 4200Å, 4300Å, or 4400Å.

In some embodiments, an adhesion layer 162 may be formed between the conductive layer 122 and the oxide layer 110, as shown in FIG. 2. In some embodiments, the adhesion layer 162 may be first formed on the oxide layer 110 using PVD, CVD, electrolytic plating, electroless plating or other suitable methods, and then the conductive layer 122 may be formed on the adhesion layer 162. In some embodiments, the adhesion layer 160 includes titanium, such as a titanium layer. The titanium layer may increase the bonding between the circuit layer 120 and the oxide layer 110. In some embodiments, the thickness of the adhesive layer 162 is about 700Å to 800Å, for example, about 710Å, 720Å, 730Å, 740Å, 750Å, 760Å, 770Å, 780Å, or 790Å.

Next, a sensing layer 132 is formed to cover the conductive layer 122, as shown in FIG. 2. In some embodiments, the sensing layer 132 may be formed on the conductive layer 122 using PVD, sputtering, CVD, PECVD, APCVD, low-pressure chemical vapor deposition (LPCVD), HDPCVD, or ALD. In some embodiments, the sensing layer 132 includes metal nitride, such as titanium nitride (TiN), or other suitable sensing materials. In some embodiments, the thickness of the sensing layer 132 is about 2000Å to 3000Å, for example, about 2100Å, 2200Å, 2300Å, 2400Å, 2500Å, 2600Å, 2700Å, 2800Å, or 2900Å.

The first portion 132a of the patterned sensing layer 132 is formed to form a first patterned sensing layer 132. Specifically, the first portion 132a of the patterned sensing layer 132 may be formed by first forming a photoresist PR1 on the sensing layer 132, as shown in FIG. 2. Then, the sensing layer 132 is etched and the photoresist PR1 is removed, as shown in FIG. 3. In some embodiments, a dry etching process may be used to pattern the first portion 132a of the sensing layer 132. For example, a dry etching gas including chlorine (Cl ₂ ) may be used for etching. It is worth noting that when etching the sensing layer 132, the etching time is shortened so that a portion of the sensing layer 132 not covered by the photoresist PR1 can remain (i.e., the second portion 132b). That is, the sensing layer 132 not covered by the photoresist PR1 is not completely etched. Therefore, the patterned sensing layer 132 includes the second portion 132b and the protruding first portion 132a, and the thickness of the first portion 132a is greater than the thickness of the second portion 132b. In some embodiments, the thickness of the second portion 132b may be about 100Å to 500Å, for example, about 150Å, 200Å, 250Å, 300Å, 350Å, 400Å, or 450Å.

It can be understood that the first part 132a of the sensing layer 132 is a three-dimensional structure to increase the contact area with the reactant. Therefore, the better the uniformity of the first part 132a of the sensing layer 132, the better the sensing accuracy can be improved. In this embodiment, shortening the etching time of the sensing layer 132 can effectively improve the three-dimensional uniformity of the first part 132a of the sensing layer 132 located in the central area and the edge area.

It is worth noting that the remaining sensing layer 132, i.e., the second portion 132b of the sensing layer 132, can prevent the conductive layer 122 below from being over-etched when etching to form the circuit layer, thereby forming an etching depth with sharper corners, thereby generating a micro-trench effect. In addition, the remaining sensing layer 132, i.e., the second portion 132b of the sensing layer 132, can also help to prevent the circuit layer from being exposed and causing leakage defects when etching the insulating layer 152 and the dielectric layer 142 (shown in FIG. 7) in the later stage.

Next, the second portion 132b of the sensing layer 132 and the conductive layer 122 are patterned to form a second patterned sensing layer 130 and a circuit layer 120. Specifically, the second portion 132b of the patterned sensing layer 132 and the conductive layer 122 can first form a photoresist PR2 on the sensing layer 132, as shown in FIG. 4. At this time, the three-dimensional structure used for sensing (i.e., the first portion 132a of the sensing layer 132) will be covered by the photoresist PR2 and will not be affected by subsequent etching. Next, the second portion 132b of the sensing layer 132, the conductive layer 122, and the adhesive layer 162 are etched, and the photoresist PR2 is removed to form the second patterned sensing layer 130 and the circuit layer 120 as shown in FIG. 5. In some embodiments, a dry etching process may be used to form the second patterned sensing layer 130 and the circuit layer 120. For example, a dry etching gas including chlorine (Cl ₂ ) may be used for etching. It is understood that the second patterned sensing layer 130 includes a second portion 130 b and a protruding first portion 130 a, and the pattern of the second portion 130 b is different from the pattern of the first portion 130 a. The pattern of the second portion 130 b of the second patterned sensing layer 130 is the same as the pattern of the circuit layer 120.

A dielectric layer 142 is then formed to cover the second patterned sensing layer 130 and the circuit layer 120, as shown in FIG6. More specifically, the dielectric layer 142 conformally and continuously covers a portion of the surface of the oxide layer 110, the sidewalls of the adhesion layer 160, the sidewalls of the circuit layer 120, and the surface of the second patterned sensing layer 130. In some embodiments, the dielectric layer 142 includes plasma-enhanced oxide (PEOX) or other similar dielectric materials.

An insulating layer 152 is formed on the dielectric layer 142, as shown in FIG7. In some embodiments, the insulating layer 152 may include silicon dioxide, a low-k material (referring to a material having a lower dielectric constant than silicon dioxide), such as silicon oxynitride, phosphosilicate glass (PSG), borophosphosilicate glass (BPSG), fluorinated silicate glass (FSG), organosilicate glasses (OSG), carbon-doped glass (SiO _x C _y ), spin-on-glass, spin-on-polymers, carbon silicide materials, compounds thereof, composites thereof, combinations thereof, or other suitable materials. These materials are deposited using a suitable method, such as spin coating, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), or other suitable methods to achieve planarization. It is understood that the insulating layer 152 can fill the recess of the dielectric layer 142 so that the top surface of the insulating layer 152 is flush with the top surface of the dielectric layer 142.

The insulating layer 152 and the dielectric layer 142 are then etched until the three-dimensional sensing portion (i.e., the first portion 130a) of the second patterned sensing layer 130 is exposed, so as to obtain the MEMS structure 10 as shown in FIG. 1. In some embodiments, the second patterned sensing layer 130 and the circuit layer 120 (and/or the adhesive layer 160) are covered by the etched dielectric layer 140, and a portion of the first portion 130a of the second patterned sensing layer 130 is exposed. In the top view direction, the etched insulating layer 150 surrounds the etched dielectric layer 140.

In summary, the present disclosure shortens the etching time of the sensing layer in the process of manufacturing the micro-electromechanical system structure to improve the uniformity of the three-dimensional sensing structure. Furthermore, shortening the etching time of the sensing layer to leave a portion of the sensing layer can not only avoid the micro-groove effect, but also avoid the leakage problem caused by exposing the circuit layer in the subsequent etching process.

Although the present disclosure has been disclosed in the form of implementation as above, it is not intended to limit the present disclosure. Anyone familiar with this art can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the scope defined in the attached patent application.

10: Micro-electromechanical system structure

100:Substrate

110: Oxide layer

120: Line layer

130: Patterned sensing layer

130a: Part 1

130b: Part 2

140: Dielectric layer

150: Insulation layer

160: Adhesive layer

Claims (10)

A micro-electromechanical system structure includes: an oxide layer disposed on a substrate; a circuit layer disposed above the oxide layer; a patterned sensing layer disposed on the circuit layer, wherein the patterned sensing layer includes a first portion and a second portion, the first portion is located on the second portion, and a pattern of the second portion is different from a pattern of the first portion; and a dielectric layer covering the patterned sensing layer, wherein the first portion of the patterned sensing layer partially protrudes from the dielectric layer and is exposed to the outside. The microelectromechanical system structure as claimed in claim 1, wherein the patterned sensing layer comprises titanium nitride. The MEMS structure as described in claim 1, wherein the patterned sensing layer includes a plurality of first portions protruding upward from the second portion at intervals from each other. The MEMS structure as described in claim 1, wherein the pattern of the second portion is the same as a pattern of the circuit layer. The micro-electromechanical system structure as described in claim 1 further includes an adhesive layer disposed between the oxide layer and the circuit layer. A method for manufacturing a micro-electromechanical system structure, comprising: forming an oxide layer covering a substrate; forming a conductive layer covering the oxide layer; forming a sensing layer covering the conductive layer, wherein the sensing layer has a second portion and a first portion located on the second portion; patterning the first portion of the sensing layer to form a first patterned sensing layer; and patterning the second portion of the sensing layer and the conductive layer to form a second patterned sensing layer and a circuit layer, wherein a pattern of the second patterned sensing layer is different from a pattern of the first patterned sensing layer. The method for manufacturing a micro-electromechanical system structure as described in claim 6, wherein the conductive layer or the circuit layer comprises a copper-aluminum alloy. The method for manufacturing a micro-electromechanical system structure as described in claim 6 further includes forming an adhesion layer between the oxide layer and the conductive layer. A method for manufacturing a micro-electromechanical system structure as described in claim 6, wherein the second patterned sensing layer has the same pattern as the circuit layer. The manufacturing method of the micro-electromechanical system structure as described in claim 6 further includes: forming a dielectric layer covering the second patterned sensing layer and the circuit layer; forming an insulating layer on the dielectric layer; and etching the insulating layer and the dielectric layer until a three-dimensional sensing portion of the second patterned sensing layer is exposed.

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