KR100655192B1 - Mems comprising planarization layer and Method thereof - Google Patents

Abstract

Depositing an insulating layer on the substrate, etching the insulating layer to form a groove corresponding to a predetermined pattern and a support portion surrounding the groove, depositing a sacrificial layer on the insulating layer, and sacrificial layer to expose the support portion Planarizing a layer, depositing a planarization layer on the support and the sacrificial layer, depositing a layered structure on the planarization layer, forming a hole in the planarization layer and the layered structure, and using the etchant through the hole. A method of manufacturing a MEMS structure including the step of removing may be provided. MEMS structure according to the present invention and a method of manufacturing the same by depositing the ribbon structure on a flat surface has an excellent electrical characteristics by making the ribbon height uniform.

MEMS, comodulators, sacrificial layers, ribbon structures.

Description

MEMS structure planarization layer and method manufacturing method including planarization layer

1 is a cross-sectional view of a MEMS structure according to the prior art.

2 is a perspective view of an optical modulator according to a preferred embodiment of the present invention.

3 is a plan view of an optical modulator according to a preferred embodiment of the present invention.

4 to 10 is a view showing a manufacturing process of the optical modulator according to a preferred embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

210: substrate

220: insulation layer

225: sacrificial layer

230: planarization layer

240: ribbon structure

250: piezoelectric

The present invention relates to a MEMS structure and a method of manufacturing the same, and more particularly, to an optical modulator manufactured using a semiconductor process.

MEMS (Micro Electro Mechanical System) is a technology that forms three-dimensional structures on silicon substrates using semiconductor manufacturing technology. The fields of application of MEMS are very diverse, and examples thereof include various sensors for vehicles, inkjet printer heads, HDD magnetic heads, and portable communication devices that are rapidly progressing in miniaturization and high functionality. The MEMS element has an injured portion on the substrate so as to be mechanically operated. Hereinafter, the optical modulator among the MEMS structures will be described. An optical modulator is a circuit or an apparatus that mounts a signal on light (optical modulation) in a transmitter when a free space of an optical fiber or an optical frequency band is used as a transmission medium. Optical modulators are used in the fields of optical memory, optical display, printer, optical interconnection, hologram, etc., and researches on the development of display devices using the same are being actively conducted.

1 is a cross-sectional view of a MEMS structure for mechanical operation according to the prior art. Referring to FIG. 1, an optical modulator including a substrate 110, an insulating layer 120, a sacrificial layer 130, a ribbon structure 140, and a piezoelectric body 150 is illustrated.

When the wavelength of light is λ, the distance between the ribbon structure 140 and the insulating layer 120 on which the lower reflective layer is formed is equal to λ / 2 when the optical modulator is not deformed (no voltage is applied). Therefore, the total path difference between the light reflected from the ribbon structure 140 and the insulating layer 120 is equal to λ so that light interferes constructively.

In addition, when an appropriate voltage is applied to the piezoelectric body 150, the distance between the ribbon structure 140 and the insulating layer 120 on which the lower reflective layer is formed is equal to λ / 4. Therefore, the total path difference between the light reflected from the ribbon structure 140 and the insulating layer 120 is equal to λ / 2 so that the light interferes with each other. As a result of such interference, the optical modulator may load a signal on the light by adjusting the amount of incident light. Here, a portion of the sacrificial layer 130 is used to support the ribbon structure 140 without being etched.

However, according to the related art, there is a problem in that the removal amount of the sacrificial layer 130 is not constant depending on the nonuniformity of the etching rate, the equipment reproducibility, the equipment uniformity, or the position in the wafer according to the difference in the pattern density or the pattern size. . In this case, there are problems such as nonuniformity in driving displacement between wafers (or LOT), nonuniformity of ribbon height, and the like. In addition, when the process of digging the sacrificial layer is used to remove the sacrificial layer, it is difficult to planarize the surface, so that it is difficult to deposit the piezoelectric body 150 or the electrical characteristics of the piezoelectric body 150 are hindered. In addition, even when the planarization process is performed using a chemical mechanical polishing (CMP) process, the interface between the heterogeneous material (insulation layer 120 and sacrificial layer 130) is completely planarized. There is a problem that is not made.

The present invention provides a MEMS structure having excellent electrical characteristics and a method of manufacturing the same by depositing the ribbon structure on a flat surface to uniform the ribbon height.

In addition, the present invention provides a MEMS structure and a method of manufacturing the same that can precisely control the sacrificial layer removal process using a planarization layer.

According to an aspect of the present invention, depositing an insulating layer on a substrate, etching the insulating layer to form a groove corresponding to a predetermined pattern and a support surrounding the groove, depositing a sacrificial layer on the insulating layer Planarizing the sacrificial layer to expose the support, depositing a planarization layer on the support and the sacrificial layer, depositing a laminate structure on the planarization layer, forming a hole in the planarization layer and the laminate structure, through the hole It is possible to provide a method for manufacturing a MEMS structure including removing a sacrificial layer using an etchant.

Here, the preset pattern may be a pattern in which the stacked structure is deposited, the insulating layer may be SiO ₂ , and the sacrificial layer may be Si.

In addition, the insulating layer may be etched by a photolithography process, and the sacrificial layer may be planarized using chemical mechanical polishing (CMP).

In addition, the method of manufacturing a MEMS structure according to the present invention may further include planarizing the planarization layer by heat treatment or chemical mechanical polishing (CMP).

According to another aspect of the invention, depositing an insulating layer on a substrate, etching the insulating layer to form a groove corresponding to a predetermined pattern and the support surrounding the groove, depositing a sacrificial layer on the insulating layer Planarizing the sacrificial layer to expose the support, depositing a planarization layer on the support and the sacrificial layer, depositing a ribbon structure on the planarization layer, and etching the planarization layer and the ribbon structure using a photolithography process. A method of manufacturing a MEMS structure may be provided, including forming a ribbon and removing the sacrificial layer using an etchant through a gap formed in the ribbon structure.

Here, the insulating layer may be SiO ₂ , and the sacrificial layer may be Si.

In addition, the method of manufacturing a MEMS structure according to the present invention may further include planarizing the planarization layer by heat treatment or chemical mechanical polishing (CMP), and may further include depositing a piezoelectric body on the ribbon structure. .

According to another aspect of the present invention, the insulating layer is located on the substrate, the groove corresponding to the pattern on which the ribbon structure is deposited and the support layer surrounding the groove, the insulating layer formed on the insulating layer, and the lower surface of the groove of the insulating layer The MEMS structure including a stacked structure spaced apart from each other by a predetermined interval and positioned on the planarization layer having a plurality of holes and formed with the plurality of holes may be provided.

According to another aspect of the invention, the insulating layer formed on the substrate, the groove corresponding to the predetermined pattern and the support portion surrounding the groove, the insulating layer is located on the insulating layer, the predetermined distance from the lower surface of the groove of the insulating layer It is possible to provide a MEMS structure including a planarization layer spaced apart from each other, a planarization layer having a plurality of holes, a ribbon structure having a plurality of holes, and a piezoelectric body positioned on the ribbon structure.

Here, the insulating layer may be SiO ₂ .

Hereinafter, preferred embodiments of a MEMS structure and a method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. In the following description with reference to the accompanying drawings, the same components are denoted by the same reference numerals. And duplicate description thereof will be omitted.

2 is a perspective view of an optical modulator precisely removing a sacrificial layer using a planarization layer according to a preferred embodiment of the present invention, and FIG. 3 is a plan view of the optical modulator according to a preferred embodiment of the present invention. 2 to 3, an optical modulator including a substrate 210, an insulating layer 220, a planarization layer 230, a ribbon structure 240, and a piezoelectric material 250 is illustrated.

The substrate 210 is a commonly used silicon substrate, and the insulating layer 220 is deposited as an etch stop layer, and an etchant for etching a material used as a sacrificial layer, where the etchant is an etching gas or an etching Solution). For example, the sacrificial layer 230 may be formed of Si, and the insulating layer 220 may be formed of Si0 ₂ having a high selectivity with respect to a gas or a solution for etching Si. Here, the insulating layer 220 may be coated with a reflective layer (not shown) to reflect incident light.

The planarization layer 230 is deposited on the removed sacrificial layer (not shown) and planarized by heat treatment and / or a CMP process. Here, since the planarization layer 230 does not have a boundary formed in the transverse direction with the insulating layer 220, the CMP process is performed on a single material, and thus the planarization layer 230 may be completely planarized. In this case, when the planarization layer 230 is planarized by heat treatment, the planarization layer 230 may be formed of a material that reflows well by heat treatment. For example, the planarization layer 230 may be formed of Boron Phosphorous Silicon Glass (BPSG), Phospho Silicate Glass (PSG), or SiO ₂ , in which reflow occurs well by heat treatment.

As described above, the ribbon structure 240 causes diffraction and interference of incident light to optically modulate the signal. The shape of the ribbon structure 240 may be configured in the form of a plurality of ribbons according to the electrostatic method, or may be provided with a plurality of open holes in the center of the ribbon according to the piezoelectric method. 2 and 3, the optical modulator is provided with a piezoelectric member 250 to control the ribbon to move up and down according to the piezoelectric method.

4 to 10 are views illustrating a manufacturing process of an optical modulator for precisely removing a sacrificial layer by using a planarization layer according to a preferred embodiment of the present invention.

Referring to FIG. 4, an insulating layer 220 is deposited on the silicon substrate 210 as an etch stop layer. Here, when the insulating layer 220 has a property of reflecting light, the insulating layer 220 may be a lower reflector of the optical modulator. Otherwise, the lower reflector may be deposited as a separate layer on the insulating layer 220. .

Referring to FIG. 5, the insulating layer 220 is etched to form a groove corresponding to a preset pattern and a support portion surrounding the groove. Here, the preset pattern is a pattern in which a stacked structure, for example, a ribbon structure is deposited, and the groove may be patterned by a photolithography process. The support part may be implemented in various shapes by enclosing the groove. For example, the support part may have a shape of a cross section of the letter 'C'. Thereafter, a sacrificial layer is deposited on the groove of the insulating layer 220 and the support part surrounding the groove.

Referring to FIG. 6, the sacrificial layer 225 is planarized until the support of the insulating layer 220 is exposed. In this case, a planarization method using a CMP process, an etch back method, a flow, or the like may be used for planarization. However, even if the planarization is attempted using a sophisticated CMP process, the interface of the heterogeneous material may not be completely planarized due to differences in polishing rates. If the surface planarization is not completed, then the ribbon structure 240 and the piezoelectric member 250 may not be properly deposited on top, and thus electrical and mechanical properties may be degraded.

Referring to FIG. 7, in order to solve the above-described problem, the planarization layer 230 is deposited on the supporting portions of the sacrificial layer 225 and the insulating layer 220. The planarization layer 230 is deposited and then planarized using a heat treatment and / or a CMP process. Unlike the case of planarizing the sacrificial layer 225, the planarization layer 230 may be completely planarized because the planarization process may be performed on a single material.

8 and 9, the ribbon structure 240 is deposited on the planarization layer 230, and then the piezoelectric material 250 is deposited on the ribbon structure 240. The optical modulator components are then patterned by photolithography. By this process, an optical modulator structure is formed. In other words, the planarization layer and the ribbon structure are etched using a photolithography process to form a laminated structure, for example, a ribbon. In addition, a process of applying a material forming the upper reflective surface and the lower reflective surface of the optical modulator and other additional processes are obvious to those skilled in the art to which the present invention pertains, and thus description thereof will be omitted.

Referring to FIG. 10, the sacrificial layer 225 is etched using an etchant through holes formed in the planarization layer 230 and the ribbon structure 240. Here, the hole penetrates the planarization layer 230 and the ribbon structure 240 when viewed from the stacking direction, and the cross section may have a circular, square, triangular, or other various shapes. In addition, the holes formed in the planarization layer 230 and the ribbon structure 240 may be applied to the present invention regardless of whether one side is opened by being located at an interface between the planarization layer 230 and the ribbon structure 240. For example, such a hole may be a gap formed in the ribbon structure 240, where the gap may be a gap formed between a plurality of ribbons or may be a plurality of gaps formed in one ribbon. . Therefore, since the insulating layer 220 is positioned on the sidewall of the sacrificial layer 225, the sacrificial layer 225 in the sidewall direction can be precisely removed.

The present invention is not limited to the above embodiments, and many variations are possible by those skilled in the art within the spirit of the present invention.

As described above, the MEMS structure and the method of manufacturing the same according to the present invention have an excellent electrical characteristic by depositing the ribbon structure on a flat surface to make the ribbon height uniform.

In addition, the MEMS structure according to the present invention and a method of manufacturing the same can be precisely controlled by using a planarization layer, the sacrificial layer formed on both side walls can be accurately etched.

Claims (14)

delete delete delete delete delete delete Depositing an insulating layer on the substrate; Etching the insulating layer to form a groove corresponding to a predetermined pattern and a support surrounding the groove; Depositing a sacrificial layer on the insulating layer; Planarizing the sacrificial layer to expose the support; Depositing a planarization layer on the support and the sacrificial layer; Depositing a ribbon structure on the planarization layer that reflects and diffracts and modulates incident light by a predetermined distance formed with the insulating layer; Forming a ribbon by etching the planarization layer and the ribbon structure using a photolithography process; And Removing the sacrificial layer using an etchant through a gap formed in the ribbon structure. The method of claim 7, wherein The insulating layer is SiO ₂ , The sacrificial layer is a MEMS structure manufacturing method. The method of claim 7, wherein Depositing a planarization layer on the support and the sacrificial layer, And planarizing the planarization layer by heat treatment or chemical mechanical polishing (CMP). The method of claim 7, wherein And depositing a piezoelectric body on the ribbon structure. delete delete An insulating layer on the substrate and having a groove corresponding to a predetermined pattern and a support surrounding the groove; A planarization layer on the insulating layer, spaced apart from a lower surface of the groove of the insulating layer by a predetermined interval, and having a plurality of holes; A ribbon structure disposed on the planarization layer and having a plurality of holes formed thereon, the ribbon structure reflecting and diffracting incident light by a predetermined distance formed from the insulating layer; And MEMS structure comprising a piezoelectric body located on the ribbon structure. The method of claim 13, The insulating layer is a MEMS structure of SiO ₂ .

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