CN102009943B - Microelectronic device and method for manufacturing microelectromechanical resonator thereof - Google Patents

Abstract

The invention relates to a microelectronic device and a manufacturing method of a micro-electromechanical resonator thereof. The manufacturing method of the micro-electromechanical resonator is characterized in that a laminated main body with a part to be suspended is formed firstly, the laminated main body comprises a silicon substrate, a plurality of metal layers and an isolation layer, the laminated main body is provided with a first etching channel extending from the metal layers to the silicon substrate, and the isolation layer is filled in the first etching channel. Then, part of the isolation layer is removed to form a second etching channel, and the rest part of the isolation layer covers the side wall of the first etching channel. Then, the isolating layer covering the side wall of the first etching channel is used as a mask, the silicon substrate is isotropically etched through the second etching channel, and the micro-electromechanical resonator suspended on the silicon substrate is formed. The manufacturing method of the micro-electromechanical resonator can be integrated with the manufacturing process of a CMOS circuit, so that the manufacturing process of a microelectronic device can be simplified, and the production cost of the microelectronic device can be reduced. In addition, the invention also provides a microelectronic device.

Description

Microelectronic device and method for manufacturing microelectromechanical resonator thereof

technical field

The invention relates to a manufacturing method of a microelectronic device and a microelectromechanical resonator, in particular to a manufacturing method of a microelectronic device and a microelectromechanical resonator with relatively low production costs.

Background technique

The development of Micro Electromechanical System (MEMS) technology has opened up a new technical field and industry, which has been widely used in various microelectronic devices with dual characteristics of electronics and mechanics, such as pressure sensors, accelerators with miniature microphone etc.

In the known manufacturing process of these microelectronic devices, the microelectromechanical resonator and the CMOS circuit are usually formed on different substrates, and then the two are packaged together to form the microelectronic device. However, this method is cumbersome, which makes it difficult to reduce the production cost of the above-mentioned microelectronic device.

It can be seen that the above-mentioned existing microelectronic device and the manufacturing method of the microelectromechanical resonator thereof obviously still have inconveniences and defects in structure and use, and further improvement is urgently needed. In order to solve the above-mentioned problems, relevant manufacturers have tried their best to find a solution, but no suitable design has been developed for a long time, and general products do not have a suitable structure to solve the above-mentioned problems. Therefore, how to improve micro The manufacturing method of the electromechanical resonator can simplify the overall manufacturing process of the microelectronic device, so as to reduce the production cost of the microelectronic device. Therefore, how to create a new manufacturing method of a microelectronic device and its MEMS resonator is one of the current important research and development topics, and it has also become a goal that the industry needs to improve.

Contents of the invention

The purpose of the present invention is to overcome the defects in the existing manufacturing method of microelectromechanical resonators, and provide a new manufacturing method of microelectromechanical resonators. The technical problem to be solved is to simplify the manufacturing process of microelectronic devices , thereby reducing the production cost of microelectronic devices, which is very suitable for practical use.

Another object of the present invention is to provide a new microelectronic device. The technical problem to be solved is to make it have a lower production cost and thus be more suitable for practical use.

The purpose of the present invention and the solution to its technical problems are achieved by adopting the following technical solutions. According to the manufacturing method of the microelectromechanical resonator proposed by the present invention, it firstly forms a laminated body with a suspended part, which includes a silicon substrate, a multi-layer metal layer and an isolation layer, wherein the insulating layer is formed on the silicon substrate, and the metal layer is formed. on the insulating layer. Moreover, the laminated body has at least one first etching channel extending from the metal layer into the silicon substrate. The isolation layer is filled in the first etching channel. Next, part of the isolation layer is removed to form a second etching channel to expose the silicon substrate, and the remaining part of the isolation layer covers the sidewall of the first etching channel. Then, using the isolation layer covering the sidewall of the first etching channel as a mask, the silicon substrate is isotropically etched through the second etching channel, so as to remove part of the silicon substrate under the floating portion. Wherein, the method for forming the laminated body includes: providing a silicon substrate; forming an insulating layer on the silicon substrate; removing part of the insulating layer and part of the silicon substrate to form at least one first opening; filling a first opening into the first opening. an oxide layer; and these metal layers are sequentially formed on the insulating layer, and each of these metal layers has at least one second opening filled with a second oxide layer, located above the first opening, wherein the first oxide layer and the first oxide layer The oxide layer forms the isolation layer, the first opening and the second openings form the first etching channel, and at least one of the second openings is smaller than the first opening, so that at least one of the metal layers protrudes beyond the first above the opening.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

In the aforementioned manufacturing method of the MEMS resonator, the method of forming the first etching channel is anisotropic etching.

In the aforementioned manufacturing method of the MEMS resonator, the method for removing part of the isolation layer is a deep reactive ion etching method.

In the aforementioned manufacturing method of the MEMS resonator, the method for isotropically etching the inside of the silicon substrate through the second etching channel includes etching with xenon fluoride gas.

In the aforementioned manufacturing method of the MEMS resonator, the laminated body further includes an insulating layer formed between the metal layers and the silicon substrate.

In the aforementioned manufacturing method of the MEMS resonator, in the manufacturing process of forming the second etching channel, part of the isolation layer is removed by using the metal layer protruding above the first opening as a mask.

In the aforementioned manufacturing method of the MEMS resonator, the insulating layer is made of non-doped polysilicon.

In the aforementioned manufacturing method of the MEMS resonator, the metal layers include aluminum layers and tungsten layers.

In the aforementioned manufacturing method of the MEMS resonator, the material of the isolation layer is silicon dioxide.

In the aforementioned manufacturing method of the MEMS resonator, there are multiple first etching channels in the laminated body, which are respectively located on two sides of the suspended part.

The purpose of the present invention and the solution to its technical problem also adopt the following technical solutions to achieve. A microelectronic device proposed according to the present invention includes a silicon substrate, a CMOS circuit and a microelectromechanical resonator. Among them, CMOS circuits are formed on a silicon substrate. The silicon substrate has an erosion area, and the MEMS resonator is suspended above the erosion area and separated from the CMOS circuit by at least one second etching channel. Wherein, the second etching channel communicates with the etching area of the silicon substrate. MEMS resonators include silicon layers, multiple metal layers and isolation layers. Wherein, the metal layers are disposed on the silicon layer, and the isolation layer covers the silicon layer and the sidewalls of the metal layers.

The purpose of the present invention and its technical problems can also be further realized by adopting the following technical measures.

In the aforementioned microelectronic device, the MEMS resonator further includes an insulating layer disposed between the silicon layer and the metal layers.

In the aforementioned microelectronic device, the insulating layer is made of non-doped polysilicon.

In the aforementioned microelectronic device, the metal layers include a plurality of first metal layers and a plurality of second metal layers, and the first metal layers and the second metal layers are alternately stacked on the silicon layer.

In the aforementioned microelectronic device, the material of the first metal layers is tungsten.

In the aforementioned microelectronic device, the material of the second metal layers is aluminum.

In the aforementioned microelectronic device, the material of the isolation layer is silicon dioxide.

By virtue of the above-mentioned technical solutions, the manufacturing method of the microelectronic device and its MEMS resonator of the present invention has at least the following advantages and beneficial effects:

1. The manufacturing method of the microelectromechanical resonator of the present invention can be integrated with the manufacturing process of the CMOS circuit, so that the microelectromechanical resonator and the CMOS circuit are integrated and fabricated on the same substrate when the microelectronic device is manufactured, thereby simplifying the microelectronics The manufacturing process of the device, thereby reducing the production cost of the microelectronic device.

2. The MEMS resonator of the present invention includes a silicon layer that is resistant to high temperature and is not prone to material fatigue, so it can have good working performance.

To sum up, the present invention has significant progress in technology and has obvious positive effects. It is a novel, progressive and practical new design.

The above description is only an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable , the following preferred embodiments are specifically cited, and in conjunction with the accompanying drawings, the detailed description is as follows.

Description of drawings

1A to 1C are schematic cross-sectional views of the manufacturing process of the MEMS resonator in an embodiment of the present invention.

2A to 2C are schematic cross-sectional views of a laminated body in a manufacturing process according to an embodiment of the present invention.

FIG. 3 is a schematic partial cross-sectional view of a microelectronic device in another embodiment of the present invention.

10: Microelectronic devices 100: Microelectromechanical resonators

11: Laminated main body 110: Part to be suspended

12: Silicon substrate 120: Cavitation area

121: Silicon layer 13: Insulation layer

14: metal layer 140: tungsten layer

141: Aluminum layer 142: The first etching channel

1422: First opening 1424: Second opening

144: Second etching channel 16: Isolation layer

162: first oxide layer 164: second oxide layer

Detailed ways

In order to further explain the technical means and effects that the present invention adopts to achieve the intended purpose of the invention, the specific implementation of the manufacturing method of the microelectronic device and its microelectromechanical resonator according to the present invention will be described below in conjunction with the accompanying drawings and preferred embodiments. The method, structure, characteristics and effects thereof are described in detail below.

1A to 1C are schematic cross-sectional views of the manufacturing process of the MEMS resonator in an embodiment of the present invention. Please refer to FIG. 1A , the implementation process of the MEMS resonator manufacturing method of this embodiment is to firstly form a laminated body 11 , which includes a silicon substrate 12 , multiple metal layers 14 and isolation layers 16 , and has a floating portion 110 . Wherein, the metal layer 14 is formed on the silicon substrate 12, and in order to avoid the short circuit between the metal layer 14 and the silicon substrate 12, an insulating layer 13 is formed between the metal layer 14 and the silicon substrate 12 in this embodiment, and its material is, for example, non-doped Miscellaneous polysilicon. The stacked body 11 has a first etching channel 142 extending from the metal layer 14 into the silicon substrate 12 . The isolation layer 16 is filled in the first etching channel 142 . It should be pointed out that the metal layer 14 in this embodiment has two first etching channels 142 respectively located on two sides of the floating portion 110 , but the present invention does not limit the number of the first etching channels 142 thereto.

Based on the above, the metal layers 14 may include alternately stacked tungsten layers 140 and aluminum layers 141 , and the material of the isolation layer 16 may be silicon dioxide. 2A to 2C are schematic cross-sectional views of a laminated body in a manufacturing process according to an embodiment of the present invention. Please refer to FIG. 2A. In this embodiment, the method for forming the laminated body 11 is to provide a silicon substrate 12 first, then form an insulating layer 13 on the silicon substrate 12, and then remove part of the silicon substrate 12 and the insulating layer 13, so as to A first opening 1422 is formed, and the first oxide layer 162 is filled in the first opening 1422 .

Referring to FIGS. 2B to 2C , multiple metal layers 14 are sequentially formed on the silicon substrate 12 , and each metal layer 14 has a second opening 1424 filled with the second oxide layer 164 and located above the first opening 1422 . Wherein, the first oxide layer 162 and the second oxide layer 164 form the isolation layer 16 , and the first opening 1422 and the plurality of second openings 1424 form the first etching channel 142 .

In detail, in this embodiment, after forming the first oxide layer 162, the tungsten layer 140 with the second opening 1424 is first formed on the substrate 12, and then the second opening 1424 is filled with the second oxide layer 164, as shown in FIG. 2B shown. Wherein, the second opening 1424 is located above the first opening 1422 . Then, an aluminum layer 141 having a second opening 1424 is formed on the tungsten layer 140, and another second oxide layer 164 is filled in the second opening 1424, as shown in FIG. 2C. By repeating the above steps, the multi-layer metal layer 14 and the isolation layer 16 filled in the first etching channel 142 shown in FIG. 1A can be formed. Wherein, the forming method of the first opening 1422 and the second opening 1424 may be an anisotropic etching method.

In particular, the depth of the first etching channel 142 formed by the first opening 1422 and the second opening 1424 extending into the silicon substrate 12 can be determined according to the target performance of the MEMS resonator to be manufactured. Specifically, if the MEMS resonator to be manufactured needs to have a high resonance frequency, the depth of the first etching channel 142 extending into the silicon substrate 12 can be deepened.

Please refer to FIG. 1B , after forming the laminated body 11, a part of the isolation layer 16 is subsequently removed to form a second etching channel 144 to expose the silicon substrate 12, while the remaining part of the isolation layer 16 covers the first etching. The side walls of the channel 142 . In detail, the method of removing part of the isolation layer 16 may be deep reactive ion etching (Deep Reactive Ion Etching, DRIE).

It is worth mentioning that, in order to leave part of the isolation layer 16 on the sidewall of the first etching channel 142, in the process of forming the laminated body 11, the size of the second opening 1424 of at least one metal layer 14 can be controlled to be smaller than The size of the first opening 1422 is such that at least one metal layer 14 protrudes above the first opening 1422 . In this way, when the second etching channel 144 is formed, the metal layer 14 protruding above the first opening 1422 can be used as a mask to remove part of the isolation layer 16, and then the sidewall of the first etching channel 142 remains The lower part of the isolation layer 16.

Please refer to FIG. 1A and FIG. 2C again. In this embodiment, for example, the dimension D ₂ of the second opening 1424 of the aluminum layer 141 is designed to be smaller than the dimension D ₁ of the first opening 1422 of the silicon substrate 12, but the present invention is not limited to this. In other embodiments, the size of the second opening 1424 of the tungsten layer 140 may also be designed to be smaller than the size of the first opening 1422 of the silicon substrate 12 . Certainly, in the present invention, the size of the second opening 1424 of the tungsten layer 140 and the aluminum layer 141 can be designed to be smaller than the size of the first opening 1422 .

In addition, the present invention does not limit which metal layer 14 is used as a mask when removing part of the isolation layer 16 , and the foregoing is only an embodiment of the present invention. Those who are familiar with this technique can make adjustments according to actual needs.

Referring to FIG. 1C , using the isolation layer 16 covering the sidewall of the first etching channel 142 as a mask, the silicon substrate 12 is isotropically etched through the second etching channel 144 to remove part of the silicon substrate under the floating portion 110 12 , and an erosion region 120 is formed in the silicon substrate 12 . This substantially completes the MEMS resonator 100 suspended at least partially above the silicon substrate 12 . In detail, the method for isotropically etching the inside of the silicon substrate 12 through the second etching channel 144 may be a xenon fluoride (XeF ₂ ) gas etching method. Moreover, since the isolation layer 16 is formed on the sidewall of the first etching channel 142 as a mask, the part of the silicon substrate 12 in contact with the isolation layer 16 can be protected from being removed by etching, so that the suspended When part of the silicon substrate 12 under the part 110 is removed, a part of the silicon substrate 12 can remain in the MEMS resonator 100 .

Based on the above, since the silicon material has a lattice structure, it is not only resistant to high temperature, but also not prone to mechanical fatigue. Therefore, the MEMS resonator 100 whose bottom is composed of a silicon layer can have better working performance. Wherein, the MEMS resonator 100 is, for example, a radio frequency resonator (RF Resonator).

As can be seen from the above, the present invention uses a CMOS manufacturing process to manufacture the MEMS resonator, so the MEMS resonator of the present invention can be fabricated on the same substrate as the CMOS circuit, so as to save subsequent combined manufacturing process steps. In order to make those skilled in the art better understand the present invention, the following examples will be given to illustrate the structure of the microelectronic device of the present invention.

FIG. 3 is a schematic partial cross-sectional view of a microelectronic device in another embodiment of the present invention. Referring to FIG. 1A and FIG. 3 , the microelectronic device 10 includes a microelectromechanical resonator 100 and a CMOS circuit 200 . Wherein, the CMOS circuit 200 is, for example, formed on the silicon substrate 12 by the same manufacturing process as the laminated body 11 . The MEMS resonator 100 is suspended above the cavity 120 of the silicon substrate 12 and includes a silicon layer 121 , a multi-layer metal layer 14 and an isolation layer 16 . Wherein, the metal layer 14 is composed of tungsten layers 140 and aluminum layers 141 stacked alternately, and is disposed above the silicon layer 121 . In this embodiment, the MEMS resonator 100 further includes an insulating layer 13, which is made of, for example, non-doped polysilicon, and is disposed between the metal layer 14 and the silicon layer 121 to avoid a gap between the metal layer 14 and the silicon layer 121. A short circuit has occurred. In addition, the isolation layer 16 covers the sidewall of the silicon layer 121 . In detail, the isolation layer 16 of this embodiment also covers the sidewalls of the tungsten layer 140 and the insulating layer 13 , and its material is, for example, silicon dioxide.

It is worth mentioning that the MEMS resonator 100 is separated from the CMOS circuit 200 by the second etching channel 144 , and the erosion region 120 in the silicon substrate 12 is etched through the second etching channel 144 . In other words, the second etching channel 144 communicates with the hollow area 120 inside the silicon substrate 12 .

It can be seen that the manufacturing method of the MEMS resonator 100 can be integrated with the manufacturing process of the CMOS circuit 200 . In other words, the MEMS resonator 100 and the CMOS circuit 200 can be formed together on the same silicon substrate 12 , so that part of the manufacturing process of the MEMS resonator 100 can be performed simultaneously during the process of manufacturing the CMOS circuit 200 . In this way, the production cost of the microelectronic device 10 can be reduced by simplifying the manufacturing process.

In summary, in the manufacturing method of the MEMS resonator of the present invention, an isolation layer is first formed on the sidewall of the first etching channel to protect the silicon substrate, so that the part of the silicon substrate that is in contact with the isolation layer forms an etching cavity. The region can be protected from being removed during etching. In this way, after the etching process of the silicon substrate, the formed MEMS resonator can still retain part of the silicon layer at the bottom, and has better working performance.

In addition, the manufacturing method of the MEMS resonator of the present invention can also be integrated with the manufacturing process of the CMOS circuit, so that the manufacturing process of the microelectronic device including the MEMS resonator and the CMOS circuit can be completed on the same substrate, thereby reducing the cost of microelectronics. The production cost of the device.

The above description is only a preferred embodiment of the present invention, and does not limit the present invention in any form. Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this field Those skilled in the art, without departing from the scope of the technical solution of the present invention, may use the technical content disclosed above to make some changes or modify equivalent embodiments with equivalent changes. Any simple modifications, equivalent changes and modifications made to the above embodiments by the technical essence still belong to the scope of the technical solution of the present invention.

Claims (7)

1. A method for manufacturing a microelectromechanical resonator, characterized in that it comprises the following steps: forming a stacked body, which includes a silicon base, multiple metal layers and at least one isolation layer, wherein the metal layers are formed above the silicon base, and the stacked body has a structure extending from the metal layers into the silicon base At least one first etching channel, the isolation layer is filled in the first etching channel, and the laminated body has a portion to be suspended; removing part of the isolation layer to form a second etching channel to expose the silicon substrate, and the remaining part of the isolation layer at least partially covers the sidewall of the first etching channel; and Using the isolation layer covering the sidewall of the first etching channel as a mask, the silicon substrate is isotropically etched through the second etching channel to remove part of the silicon substrate below the floating portion, and the An etched area is formed in the silicon substrate; Wherein, the method for forming the laminated body includes: providing the silicon substrate; forming an insulating layer on the silicon substrate; removing part of the insulating layer and part of the silicon substrate to form at least a first opening; filling a first oxide layer in the first opening; and These metal layers are sequentially formed on the insulating layer, and each of the metal layers has at least one second opening filled with a second oxide layer, located above the first opening, wherein the first oxide layer and the The second oxide layer constitutes the isolation layer, the first opening and the second openings constitute the first etching channel, and at least one of the second openings is smaller than the first opening, so that at least one of the metal layers One protrudes above the first opening. 2. The manufacturing method of the MEMS resonator according to claim 1, wherein the method of forming the first etching channel is anisotropic etching, and the method of removing part of the isolation layer is deep reactive ion etching Law. 3 . The manufacturing method of the MEMS resonator according to claim 1 , wherein the method of isotropically etching the inside of the silicon substrate through the second etching channel comprises etching with xenon fluoride gas. 4 . 4. The manufacturing method of the MEMS resonator according to claim 1, wherein the insulating layer is made of non-doped polysilicon. 5. The manufacturing method of the MEMS resonator according to claim 4, wherein in the manufacturing process of forming the second etching channel, the metal layer protruding above the first opening is used as a mask to Part of this isolation layer is removed. 6 . The manufacturing method of the MEMS resonator according to claim 1 , wherein the metal layers include aluminum layers and tungsten layers, and the isolation layer is made of silicon dioxide. 7 . The manufacturing method of the microelectromechanical resonator according to claim 1 , wherein there are a plurality of first etching channels in the laminated body, which are respectively located on two sides of the suspended part. 8 .

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