KR101388927B1

KR101388927B1 - Method of fabricating mems device using amorphous carbon layer with promoted adhesion

Info

Publication number: KR101388927B1
Application number: KR1020130027538A
Authority: KR
Inventors: 임성규; 김영수; 김한흥; 박상현; 황욱중; 이귀로
Original assignee: 한국과학기술원
Priority date: 2013-03-14
Filing date: 2013-03-14
Publication date: 2014-04-25

Abstract

Provided is a method for producing an MEMS device using an amorphous carbon film as a sacrificial layer. According to an embodiment of the present invention, the method comprises the steps of: producing a bottom structure including metallic patterns; producing an adhesion reinforcing layer that covers the metallic patterns of the bottom structure and includes at least one among an oxide film, a nitride film, a nitrifying film, and an amorphous silicon film; producing an amorphous carbon film as a sacrificial layer on the adhesion reinforcing layer; producing an insulating and supporting layer on the amorphous carbon film; producing via holes formed in order to penetrate through the insulating and supporting layer and amorphous carbon film and make the bottom structure exposed therethrough sequentially by forming an etching protection film on the insulating and supporting layer, by performing only one photolithography procedure, and by etching the insulating and supporting layer and the amorphous carbon film at a time; producing a top structure including a sensor structure on the insulating and supporting layer; producing at least one through-hole that penetrates through the insulating and supporting layer; and removing the amorphous carbon film through the through-hole so that the bottom structure and top structure are disposed to be separated from each other.

Description

Method of fabricating MEMS device using amorphous carbon layer with promoted adhesion}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to semiconductor devices, and more particularly, to a MEMS (Micro Electro Mechanical Systems) device and a manufacturing method thereof.

In general, a MEMS device refers to a device that integrates mechanical element parts, sensors, actuators, and electronic circuits on a single silicon substrate. Current products include a printer head, a pressure sensor, an acceleration sensor, a gyroscope, a DMD Projector).

The main part is fabricated using a semiconductor process, but a process called a sacrificial layer etching, which is not used for the fabrication of a semiconductor integrated circuit, needs to form a three-dimensional shape when a semiconductor integrated circuit is fabricated by processing the planar . This process is a method of fabricating a structure by patterning the shape of a structure using a sacrificial layer and a structure thin film on a silicon substrate and removing the sacrificial layer. Silicon or an organic polyimide has been used as a sacrificial layer for maintaining a constant space between the lower electrode or the lower structure and the upper structure.

However, in the conventional MEMS device fabrication, when the silicon is used as the sacrificial layer, the etching selectivity with the oxide film is excellent, but the etching selectivity with the metal such as nitride film and tungsten is not good, and the polyimide is used as the sacrificial layer. There is a problem that the quality is reduced by using a lift off method that is contained, and proceeds at a low temperature in the subsequent process.

The present invention is to solve the various problems including the above problems, has an excellent etching selectivity with various kinds of inorganic materials, and can easily adjust the thickness of the film according to the device, the conventional MEMS in terms of performance and shape It is an object of the present invention to provide a MEMS device and a manufacturing method which are superior to devices and can utilize existing semiconductor processes. However, these problems are exemplary and do not limit the scope of the present invention.

A method of manufacturing a MEMS device according to one aspect of the present invention is provided. The method of manufacturing a MEMS device may include forming a lower structure including a metal pattern; Forming an adhesive reinforcement layer covering all metal patterns of the lower structure and including at least one of an oxide film, a nitride film, an oxynitride film, and an amorphous silicon film; Forming an amorphous carbon film as a sacrificial layer on the adhesion reinforcing layer; Forming an insulating support layer on the amorphous carbon film; Performing only one photolithography process on the insulating support layer to etch the insulating support layer and the amorphous carbon film at one time to form via holes through the insulating support layer and the amorphous carbon film to expose the lower structure; Forming an upper structure including a sensor structure on the insulating support layer; Forming at least one through hole penetrating the insulating support layer; And removing all of the amorphous carbon film through the through holes so that the lower structure and the upper structure are spaced apart from each other. .

In the manufacturing method, the forming of the amorphous carbon film may be performed using chemical vapor deposition (CVD).

In the manufacturing method, the sensor structure may be formed in a temperature range of 250 ℃ to 450 ℃.

In the manufacturing method, removing the amorphous carbon film may include a dry etching method. In addition, the dry etching method may be performed by using an oxygen (O 2) plasma.

In the manufacturing method, the forming of the upper structure may further include forming an insulating support layer on the amorphous carbon film.

The method may further include forming metal anchors on the lower electrodes to be connected to the lower electrodes through the via holes after the step of forming the via holes.

In the manufacturing method, the forming of the upper structure may further include forming an absorbing layer on the insulating support layer.

In the manufacturing method, the lower structure may include a read integrated circuit (ROIC) for reading the electrical characteristics of the sensor.

In the manufacturing method, the sensor structure may include an infrared sensor.

In the manufacturing method, forming the via holes exposing the lower structure through the insulating support layer and the amorphous carbon film may be performed by only one photolithography process.

According to an embodiment of the present invention as described above, since it has an excellent etch selectivity with various types of inorganic materials and can easily adjust the thickness of a film according to a device, it is superior in performance and shape to conventional MEMS devices , A MEMS device that can utilize an existing semiconductor process can be implemented. In addition, by introducing an adhesion reinforcing layer between the amorphous carbon film and the metal pattern of the lower structure, it is possible to prevent the peeling between the amorphous carbon film and the metal pattern of the lower structure. Of course, the scope of the present invention is not limited by these effects.

FIGS. 1 to 6 are sectional views schematically showing a MEMS device and a method of manufacturing the MEMS device according to an embodiment of the present invention.
7 is a cross-sectional view schematically illustrating a MEMS device manufactured according to another embodiment of the present invention.
8 to 11 are sectional views showing a method of manufacturing a MEMS device according to another embodiment of the present invention.
12 is a photograph of a cross section of a structure in which an amorphous carbon film is formed according to an embodiment of the present invention.
13 is a photograph of a cross section of a structure in which an amorphous carbon film is formed according to a comparative example of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, Is provided to fully inform the user. Also, for convenience of explanation, the components may be exaggerated or reduced in size.

FIGS. 1 to 6 are sectional views schematically showing a MEMS device and a method of manufacturing the MEMS device according to an embodiment of the present invention.

Referring to FIG. 1, a substructure 12 may be provided. For example, the substructure 12 may comprise suitable logic circuitry, such as a Read Out Integrated Circuit (ROIC). The read integrated circuit can read the electrical characteristics of the sensor structure 23. The readout integrated circuit can be manufactured by forming a CMOS device on a substrate. Further, the substructure 12 may further include an insulating layer 15 on the substrate and a lower electrode 14b and a reflective layer 14c on the insulating layer 15. [ The lower structure 12 may include a metal pattern, such as the lower electrode 14b and / or the reflective layer 14c.

The lower electrode 14b may be used to electrically connect the circuit element and the sensor element in the logic circuit. The lower electrode 14b may be formed to protrude on the insulating layer 15 or may be formed by forming a trench pattern in the insulating layer 15 and then filling it with a metal layer. Reflective layer 14c may be used to reflect light incident on underlying structure 12. Particularly, in the case of using a damascene method of embedding the trench pattern in the insulating layer 15 and embedding the trench pattern in the metal layer to form the lower electrode 14b and the reflection layer 14c, the amorphous carbon film to be described later is formed by chemical vapor deposition Can be very advantageous in terms of planarization when formed.

Referring to FIG. 2, a sacrificial layer 16 may be formed on the lower structure 12. The sacrificial layer 16 is used to support the upper structure (23 of FIG. 6) described below on the lower structure 12, but finally at least some or all may be removed. For example, the sacrificial layer 16 may include an amorphous carbon film.

For example, the sacrificial layer 16 may be formed using Chemical Vapor Deposition (CVD). The amorphous carbon film 16 can be deposited by various techniques, but plasma enhanced chemical vapor deposition (PECVD) can be used, for example, because of cost effectiveness and film property controllability. Plasma enhanced chemical vapor deposition (CVD) may introduce materials including liquid or gaseous hydrocarbons into carrier gas and helium and argon as plasma initiation gases into the chamber. The plasma can be transferred into the chamber to produce excited CH-radicals, which can be chemically constrained to the surface of the substrate located in the chamber to form an a-C: H film on the surface of the substrate. In one embodiment of the present invention, a damascene method may be used in which a trench pattern is formed in the insulating layer 15 and then the trench pattern is embedded in the metal layer to realize the lower electrode 14b and the reflective layer 14c. In this case, the sacrificial layer 16 composed of the amorphous carbon film may not be subjected to a separate planarization process such as CMP. If the amorphous carbon film is deposited on the uneven metal structure and the amorphous carbon film is flattened by CMP, peeling may occur because the adhesion between the metal and the amorphous carbon film is poor.

Accordingly, the sacrificial layer 16 may be formed in a manner compatible with a back-end process such as a metallization process of a semiconductor device. That is, the sacrificial layer 16 may be formed by using a post-process used for manufacturing a conventional semiconductor device, not a MEMS process. Therefore, following the formation of the lower structure 12, it is possible to proceed with the sacrificial layer 16 and the subsequent metal process by applying most of the process technology used in the existing semiconductor post-process as it is to reduce the manufacturing cost and easy mass production Become.

On the other hand, when the sacrificial layer 16 is formed using a material such as polyimide, it is not easy to apply the high-temperature process in the subsequent metal deposition process due to moisture reabsorption, The metal should be deposited using the method. In this case, there is a disadvantage that the step coverage is not good and a lot of impurities remain in the metal.

However, in this embodiment, the sacrificial layer 16 may be formed of an amorphous carbon film using a CVD method at a middle temperature range of about 200 캜 to 600 캜. In this case, the metal deposition process can be performed using the CVD method. The CVD method is excellent in step coverage, is excellent in wiring shape and electrical characteristics, and can improve the reliability of the metal deposition process.

On the other hand, the thickness of the sacrificial layer 16 may be appropriately selected in consideration of the separation distance between the lower structure 12 and the upper structure and the subsequent removal burden. For example, in the MEMS structure like this embodiment, the thickness of the sacrificial layer 16 may be selected in the range of 0.5 to 5 mu m. However, in another embodiment, the thickness of the sacrificial layer 16 may be selected without being limited to this range. Alternatively, the insulating support layer 17 may be formed on the sacrificial layer 16. For example, the insulating support layer 17 may be formed of an oxide film by CVD.

As described above, the lower structure 12 may include a metal pattern, such as the lower electrode 14b and / or the reflective layer 14c. When the amorphous carbon film 16 is formed on the metal material, poor adhesion may occur. In order to solve this problem, in one embodiment of the present invention, the adhesion reinforcing layer 160 covering all or at least a portion of the metal patterns such as the lower electrode 14b and / or the reflective layer 14c constituting the lower structure 12 is provided. By forming the interlayer between the lower structure 12 and the amorphous carbon film 16, peeling between the amorphous carbon film 16 and the lower structure 12 may be prevented. The adhesion reinforcing layer 160 may include at least one of an oxide film, a nitride film, a nitride oxide film, and an amorphous silicon film.

For example, when the lower structure 12 needs to be planarized, a metal pattern such as the lower electrode 14b and / or the reflective layer 14c is formed, and then planarization is performed through an oxide film deposition and planarization process (CMP) and an oxide layer etch. Achieve. Since the amorphous carbon film 16 forms a layer by chemical vapor deposition (CVD), when the lower structure of the amorphous carbon film 16 has a step, the amorphous carbon film 16 and the upper structure cannot be planarized. Next, the amorphous carbon film 16 is deposited on the exposed portion of the metal pattern by the planarization process (CMP). Deposit. If the planarization of the lower structure 12 is not necessary, a non-metal layer such as a thin oxide film, a nitride film, an oxynitride film, or an amorphous silicon layer of 500 nm or less is formed on a metal pattern such as the lower electrode 14b and / or the reflective layer 14c. After depositing the phosphorus adhesion-enhancing layer 160, the amorphous carbon film 16 may be deposited.

3, the insulating support layer 17 and the sacrificial layer 16 may be patterned by a single photolithography process to form the sacrificial layer 16d having the via holes 19 and the insulating support layer 17a at the same time have. In addition, the adhesion reinforcing layer 160 exposed in the process of forming the via holes 19 may be removed. For example, the via holes 19 can be formed by forming a photoresist pattern using photolithography, and etching the insulating support layer 17 and the sacrifice layer 16 simultaneously using the photoresist pattern as an etching protection film . For example, the via holes 19 may be formed to expose the lower electrodes 14b, and then the lower electrodes 14b may be used as a path for connecting the lower electrodes 14b to the upper structure. If the sacrificial layer 16 is made of organic material polyimide, after the sacrificial layer 16 is etched by the first photolithography process to form the via holes 19, 2 photolithography process. This is because outgassing occurs in the polyimide exposed by the first photolithography process, and therefore, a separate process for covering the exposed portion of the polyimide is further required before the second photolithography process to be. However, in the embodiments of the present application, since the sacrificial layer 16 is composed of an amorphous carbon film, the above-described problem of outgassing does not occur, and thus, there is no need to prevent the exposure of the amorphous carbon film in the etching process. By the lithography process, the insulating support layer 17 and the sacrificial layer 16 can be etched at once, that is, simultaneously. By replacing the sacrificial layer 16 with an amorphous carbon film in polyimide, the inventor not only prevents the problems such as water resorption, poor step coverage, impurities in subsequent processes, etc., but also utilizes the characteristics of the amorphous carbon film. In the process of forming the via holes 19, the number of photolithography processes is simplified from two times to one time, thereby providing a manufacturing method that can significantly reduce the manufacturing cost.

Referring to FIG. 4, the metal anchors 21 may be formed to be connected to the lower electrodes 14b through the via holes 19. FIG. For example, the metal anchors 21 can be formed by forming a metal layer on the lower electrodes 14b exposed by the via holes 19 by CVD and patterning the metal layers. Examples of such a metal layer include a tungsten (W) layer. These metal anchors 21 may be used as via plugs for electrically connecting the lower electrodes 14b to the upper structure.

Referring to FIG. 5, an upper structure may be formed on the sacrificial layer 16d. For example, the absorbent layer 22 may be formed on the resulting product with the metal anchors 21 and the sensor structure 23 formed on the absorbent layer 22. The absorbing layer 22 may be patterned to include a plurality of holes. For example, the absorbent layer 22 may comprise a metal capable of absorbing infrared radiation.

The sensor structure 23 may include various sensors used in a MEMS structure, and may include an infrared sensor, an ultraviolet sensor, an X-ray sensor, a laser sensor, or the like. For example, in the case of an infrared sensor, it may include a resistance element, a thermoelectric element, and the like. In the case of a bolometer including a resistance element, the resistance may vary depending on the degree of infrared rays absorbed, for example, amorphous silicon, vanadium oxide, and the like.

If the sacrificial layer 16 is used as a polyimide series rather than an amorphous carbon film, temperature constraints may occur in the process of forming the sensor structure 23. That is, when the sacrificial layer 16 of the polyimide series is used, the process of forming the sensor structure 23 should be carried out at 250 ° C. or lower, but it is possible to prevent deterioration of properties in subsequent processes due to outgassing generated from the polyimide. have. When the temperature is restricted in the process of forming the sensor structure 23, the impurity content of the material forming the sensor structure 23 increases, which may lead to deterioration of sensor characteristics.

In an embodiment of the present invention, the purity of the material constituting the sensor structure 23 is increased by raising the temperature of the process of forming the sensor structure 23 using the amorphous carbon film as the sacrificial layer 16 to 250 ° C to 450 ° C. In addition, it has the following advantages. Electrical properties are much more uniform and better with respect to the membrane in the sensor structure 23. The 1 / f noise is reduced to improve the noise equivalent temperature difference (NETD), and it is possible to implement a thermal camera having low manufacturing cost by enabling a sensor operation without a thermoelectric cooler (TEC) or a shutter. The mechanical properties of the membrane and the chemical selectivity (for dry ashing) are also good. This increases yield and quality. In addition, the thermal window is much larger in subsequent heat treatment processes such as eutectic bonding and getter activation, which are required for vacuum packages. That is, getters activated at 250 ° C or higher, or even AlGe bonding at 420 ° C are possible.

As described above, since the temperature of the process of forming the sensor structure 23 using the amorphous carbon film as the sacrificial layer 16 may be raised to 250 ° C. to 450 ° C., the material forming the sensor structure 23 may include zirconium, Hafnium, polycrystalline silicon, amorphous silicon, monocrystalline silicon, silicon dioxide, silicon nitride, silicon carbide, organosilica glass, tungsten, tungsten nitride, tungsten carbide, aluminum, aluminum alloy, aluminum oxide, aluminum nitride, aluminum carbide, tantalum, tantalum At least any one of an alloy, tantalum oxide, titanium, titanium alloy, titanium nitride, titanium oxide, copper, copper alloy, copper oxide, vanadium and vanadium oxide may be applied.

Referring to FIG. 6, a second insulating support layer 25 may be formed on the sensor structure 23. For example, the second insulating support layer 25 may include an oxide film. The through holes 27 may be formed through the second insulating support layer 25, the sensor structure 23, the absorbent layer 22, and the insulating support layer 17a. For example, the through holes 27 are formed by using a photolithography technique to form a photoresist pattern, and the second insulating supporting layer 25, the sensor structure 23, the absorbing layer 22 And the insulating support layer 17a. The number of the through holes 27 can be appropriately selected in one or more ranges in consideration of the etching rate of the sacrifice layer 16d. The shape of the through holes 27 can be variously modified, and a cantilever pattern can be realized by the through holes 27.

Then, the sacrificial layer 16d may be removed through these through holes 27 to define the empty space C. The empty space C can contribute to enhancement of the infrared absorption efficiency by causing the infrared ray to be reflected through the reflection layer 14c and incident on the sensor structure 23 again.

For example, when the sacrificial layer 16d is an amorphous carbon film, the sacrificial layer 16d may be etched by using wet etching or dry etching. However, stiction may occur when wet etching is used, but dry etching may be free from such a problem. For example, dry etching can be performed using an oxygen (O 2) plasma. Meanwhile, in the process of etching the sacrificial layer 16d, the adhesion reinforcing layer 160 formed on the lower structure 12 may be etched.

The thus formed MEMS device may include a superstructure including a substructure 12 and a sensor structure 23. [ Between the substructure 12 and the sensor structure 23, an empty space C where the sacrificial layer 16, 16d is removed may be defined. The sensor structure 23 may be electrically connected to the lower electrodes 14b through the metal anchors 21. [ Thus, the sensor structure 23 and the logic circuitry of the underlying structure 12, e.g., the readout integrated circuit, can be structurally connected to one another to form a MEMS device. Such a MEMS device may include various sensor structures, and may include, for example, an infrared sensor, an ultraviolet sensor, an X-ray sensor, a laser sensor, and the like.

7 is a cross-sectional view schematically illustrating a MEMS device manufactured according to another embodiment of the present invention.

Referring to FIG. 7, the lower electrode 14 may be formed in the first substrate 12a. The lower electrode 14 may be formed by implanting an impurity of the second conductivity type into the first substrate 12a of the first conductivity type and heat-treating the first substrate 12a. Here, the first conductivity type and the second conductivity type may be n-type and p-type, respectively, or vice versa. In a modified embodiment, the lower electrode 14 may not be formed in the first substrate 12a but may be disposed on the upper surface of the first substrate 12a.

An amorphous carbon film pattern 16c may be formed on a portion of the first substrate 12a. There is no amorphous carbon film pattern 16c on the remaining portion of the first substrate 12a. For example, the amorphous carbon film pattern 16c may be formed to expose at least a part of the first substrate 12a located on the upper surface of the lower electrode 14 and the lower electrode 14. A second substrate 18a and an upper electrode 20 are disposed on the amorphous carbon film pattern 16c. The upper electrode 20 may be disposed at a position opposite to the lower electrode 14. [ Accordingly, the lower electrode 14 may be disposed apart from the upper electrode 20 and the amorphous carbon film pattern 16c. Of course, the amorphous carbon film pattern 16c may not be interposed between the lower electrode 14 and the upper electrode 20.

For convenience, a structure including the first substrate 12a and / or the lower electrode 14 described above is referred to as a lower structure, and a structure including the second substrate 18a and / or the upper electrode 20 is referred to as an upper structure You can name it. In this case, the upper structure and the lower structure can be disposed apart from each other by the amorphous carbon film pattern 16c.

As described above, the upper structure may be disposed on the first substrate 12a and the amorphous carbon film pattern 16c. The upper structure may further include a solder bonding layer 24 and a packaging cap layer 26 in addition to the second substrate 18a and the upper electrode 20. [ The second substrate 18a may correspond to a device layer in a MEMS device. The thickness of the device layer can be arbitrarily adjusted and can have various types of structures. The second substrate 18a may include an upper electrode 20, and the upper electrode 20 injects a second conductive material into a predetermined portion of the second substrate 18a and the second substrate. (18a) can be formed by heat treatment. The upper electrode 20 may be formed at a position passing through the amorphous carbon film pattern 16c and facing the lower electrode 14. [

The upper electrode 20 and the lower electrode 14 are spaced apart by a distance d1 corresponding to the thickness of the amorphous carbon film pattern 16c. Therefore, the upper electrode 20 may be formed so that the position on the lower electrode 14 can be changed.

When the upper electrode 20 and the lower electrode 14, which are conductive flat plates, are arranged so as to face each other in parallel, the capacitance between the two electrodes is proportional to the dielectric constant of the medium between the two electrodes and the area of the two electrodes facing each other, It can be approximated to a value in inverse proportion to the separation distance d1 between the two electrodes. When relative movement occurs between the two electrodes relatively vertically and / or horizontally, the gap or overlapping area between the two electrodes changes and the capacitance changes. Therefore, by outputting the change in capacitance as an electrical signal it is possible to measure the relative displacement between the two electrodes.

A packaging cap layer 26 may be disposed on the second substrate 18a. The packaging cap layer 26 may serve to protect the MEMS device from the outside. The interior 28 of the packaging cap layer 26 may be sealed to maintain a vacuum. A solder joint layer 24 may be interposed between the second substrate 18a and the packaging cap layer 26. [ The solder joint layer 24 may include at least one of gold, silver, copper, tin, indium and silicon.

Further, the MEMS device may further include a penetrating electrode 32 for electrically connecting the lower electrode 14 and / or the upper electrode 20 to the outside through the first substrate 12a and / or the amorphous carbon film pattern 16c And a conductive pad 34 electrically connected to the penetrating electrode 32 on the lower surface of the first substrate 12a. The upper electrode 20 and the second substrate 18a are separated from each other in FIG. 1 according to the cross-sectional view. However, since the upper electrode 20 and the second substrate 18a are actually connected to each other, 20 may be electrically connected. The penetrating electrode 32 may be made of a conductive material, for example, a material such as copper, tungsten, and aluminum.

For example, a MEMS device according to this embodiment can be used as a gyro sensor, but the scope of this embodiment is not limited thereto.

8 to 11 are sectional views schematically showing a manufacturing process of a MEMS device according to another embodiment of the present invention.

Referring to FIG. 8, first a first substrate 12 is prepared. The first substrate 12 may be a silicon substrate and may include a variety of semiconductor materials, such as a Group IV semiconductor, a Group III-V compound semiconductor, or a Group II-VI oxide semiconductor. For example, a Group IV semiconductor may include germanium or silicon-germanium in addition to silicon. Examples of the substrate include a gallium-arsenic substrate, a ceramic substrate, a quartz substrate, and a glass substrate for a display.

Next, impurities are implanted into the first substrate 12, and the first substrate 12 is heat-treated to form the lower electrode 14. Next, as shown in FIG. When the lower electrode 14 is formed by implanting impurities, the lower electrode 14 may be formed in the first substrate 12 without protruding from the upper surface of the first substrate 12. The lower electrode 14 thus formed has the same level as the upper surface of the lower electrode 14 and the upper surface of the first substrate 12. On the other hand, in the modified embodiment, the lower electrode 14 may protrude from the upper surface of the first substrate 12a.

The process of injecting impurities may include an ion implant process or a doping process. In the impurity implantation process, for example, an n-type impurity source such as PH3, AsH3 or the like or a p-type impurity source such as BF3, BCl3 or the like may be used. In this case, the lower electrode 14 may have characteristics of a conductor having excellent electrical conductivity.

An amorphous carbon film can be formed on the substrate 12a as a sacrificial layer. Referring to FIG. 9, the amorphous carbon film 16 may be formed on the first substrate 12 having the lower electrode 14 formed therein. In forming the amorphous carbon film 16, the amorphous carbon film 16 may be formed by chemical vapor deposition. The amorphous carbon film 16 can be deposited by a variety of techniques, but plasma enhanced chemical vapor deposition (PECVD) can be used, for example, due to cost effectiveness and film property controllability.

The temperature at which this chemical vapor deposition method is performed may be performed at 200 ° C to 600 ° C. For example, if argon is used as a diluent gas, the substrate temperature may be reduced to as low as about 300 DEG C during deposition. A lower process temperature for the substrate can lower the thermal budget of the process and protect the device formed on the substrate from dopant migration. In addition, the process can be performed at the same temperature as the post-semiconductor process. Therefore, the manufacturing cost can be lowered because the process technologies already used in the conventional semiconductor process can be utilized sufficiently.

The first substrate 12, which is a lower structure, may include a metal pattern like the lower electrode 14. When the amorphous carbon film 16 is formed on the metal material, poor adhesion may occur. In order to solve this problem, in another embodiment of the present invention, an adhesive reinforcing layer 160 covering all of the metal patterns, such as the lower electrode 14 constituting the first substrate 12 as the lower structure, is formed as the first substrate as the lower structure. By forming it between the 12 and the amorphous carbon film 16, peeling between the amorphous carbon film 16 and the lower structure 12 can be prevented. The adhesion reinforcing layer 160 may include at least one of an oxide film, a nitride film, a nitride oxide film, and an amorphous silicon film.

Referring to FIG. 10, an upper structure may be formed on the first substrate 12 and the amorphous carbon film 16. The superstructure may include a second substrate 18a and an upper electrode 20. The second substrate 18a may be, for example, a silicon substrate. The second substrate 18a may correspond to a device layer in a MEMS device. The thickness of the device layer may be arbitrarily adjusted through bonding and / or thinning of the silicon substrate, and may have a range of, for example, 10 mu m to 100 mu m. Subsequently, the second substrate 18a is subjected to an exposure, an etching, and a cleaning process. For example, the etching process may be performed using a so-called deep reactive ion etching (RIE) method.

The second substrate 18a may include a predetermined structure of various forms. For example, the upper electrode 20 may be formed by implanting impurities into a predetermined portion of the second substrate 18a and heat treating the second substrate 18a. The process of injecting impurities may include an ion implant process or a doping process. Meanwhile, in the impurity implantation process, for example, an n-type impurity source such as PH3 or AsH3 or a p-type impurity source such as BF3 or BCl3 may be used.

Forming the upper structure may further include depositing tungsten by chemical vapor deposition. Tungsten deposition by chemical vapor deposition can be produced using a WF6 / H2 mixed gas. WF6 can be reduced by silicon, hydrogen and silane, and upon contact with silicon, a selective reaction can be started from the reduction reaction of silicon. Hydrogen reduction reactions can rapidly deposit tungsten on the nucleation layer while forming plugs, and silane reduction reactions can achieve faster deposition rates and smaller tungsten grain sizes than those obtainable in hydrogen reduction reactions. The tungsten thin film formed by such a reaction has a good step coverage property and a low resistance component compared to other materials, and thus may be treated as an important conductor material.

10 to 11, a portion of the amorphous carbon film 16 interposed between the lower electrode 14 and the upper electrode 20 may be removed to form the amorphous carbon film pattern 16b. The process of removing a portion of the amorphous carbon film 16 may be removed after forming at least one of the upper structures, for example, the second substrate 18a, and may use wet etching and / or dry etching. For example, a portion of the amorphous carbon film 16 may be easily removed by using an oxygen (O 2) plasma, which is one of dry etching methods. By using an oxygen (O 2) plasma, it is possible to have an excellent etching selectivity with many kinds of inorganic materials and to easily control the film thickness. Therefore, the lower electrode 14 may be easy to adjust the separation distance between the upper electrode 20 and the two, it is easy to ensure the uniformity of the capacitance can ensure a stable operation of the MEMS device.

The upper structure may further include a solder bonding layer 24 and a packaging cap layer 26 in addition to the second substrate 18a and the upper electrode 20. The packaging cap layer 26 may be attached on the second substrate 18a and the interior 28 of the packaging cap layer 26 may be sealed to maintain a vacuum and the second substrate 18a and the packaging cap layer 26 may be interposed between the solder joint layer 24 and the solder joint layer 24. The material forming the solder joint layer 24 may include at least one of gold, silver, copper, tin, indium and silicon. For example, the solder joint layer 24 may be comprised of various binary or ternary solder alloys such as copper / tin, gold / indium, gold / tin, gold / silicon, copper / gold /

As described above, since the MEMS device according to the technical idea of the present invention forms the amorphous carbon film pattern as the sacrificial layer on the silicon substrate, the tungsten deposition process by the chemical vapor deposition method can be used and the step coverage is excellent A device excellent in wiring shape and electrical characteristics can be manufactured. In addition, since the process is performed at the same temperature as the post-semiconductor process, the process technologies already used in the conventional semiconductor process can be fully utilized.

Furthermore, the amorphous carbon film is peeled by covering the metal pattern of the lower structure and including an adhesion reinforcing layer between the metal pattern and the amorphous carbon film of the lower structure, the adhesive reinforcing layer including at least one of an oxide film, a nitride film, an oxynitride film, and an amorphous silicon film. Peeling phenomenon can be prevented.

12 is a photograph of a cross section of a structure in which an amorphous carbon film is formed according to an embodiment of the present invention, and FIG. 13 is a photograph of a cross section of a structure in which an amorphous carbon film is formed according to a comparative example of the present invention.

Referring to FIG. 12, the lower structure may include the metal pattern 14 and the insulating layer 15 as described above. As illustrated in FIG. 2, the metal pattern 14 may include a lower electrode 14b and / or a reflective layer 14c. The inventors have observed a peeling phenomenon of the amorphous carbon film 16 by interposing the adhesion reinforcing layer 160 including at least one of an oxide film, a nitride film, an oxynitride film, and an amorphous silicon film between the metal pattern 14 and the amorphous carbon film 16. It was confirmed that can be prevented. On the contrary, referring to FIG. 13, when the amorphous carbon film 16 is directly formed directly on the metal pattern 14 of the lower structure, it is confirmed that the peeling of the amorphous carbon film 16 occurs due to poor adhesion. Could. This peeling (P) phenomenon of the amorphous carbon film 16 causes the failure of subsequent processes.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

Claims

Forming a lower structure including a metal pattern;
Forming an adhesive reinforcement layer covering the metal pattern of the lower structure and including at least one of an oxide film, a nitride film, a nitride oxide film, and an amorphous silicon film;
Forming an amorphous carbon film as a sacrificial layer on the adhesion reinforcing layer;
Forming an insulating support layer on the amorphous carbon film;
Performing only one photolithography process on the insulating support layer to etch the insulating support layer and the amorphous carbon film at one time to form via holes through the insulating support layer and the amorphous carbon film to expose the lower structure;
Forming an upper structure including a sensor structure on the insulating support layer;
Forming at least one through hole penetrating the insulating support layer; And
Removing all of the amorphous carbon film through the through holes such that the lower structure and the upper structure are spaced apart from each other; Including, MEMS device manufacturing method.

The method of claim 1,
Forming the amorphous carbon film is carried out using chemical vapor deposition (CVD) at a temperature of 200 ℃ to 600 ℃, MEMS device manufacturing method.

The method of claim 1,
Wherein the sensor structure is formed at a temperature range of 250 ° C to 450 ° C.

The method of claim 1,
Removing the amorphous carbon film includes a dry etching method performed by using an oxygen (O ₂ ) plasma (Plasma), MEMS device manufacturing method.

The method of claim 1, wherein the forming of the upper structure further comprises forming an insulating support layer on the amorphous carbon film.

The method of claim 1, further comprising forming metal anchors on the lower electrodes to be connected to the lower electrodes through the via holes after forming the via holes.

The method of claim 1,
And the lower structure comprises a read integrated circuit (ROIC) for reading the electrical characteristics of the sensor.