KR20160120558A

KR20160120558A - Method of manufacturing three-dimensional inertia measurement system and three-dimensional inertia measurement system using the same

Info

Publication number: KR20160120558A
Application number: KR1020150049783A
Authority: KR
Inventors: 문상희; 이종성
Original assignee: 주식회사 스탠딩에그
Priority date: 2015-04-08
Filing date: 2015-04-08
Publication date: 2016-10-18
Also published as: WO2016163586A1

Abstract

The present invention relates to a three-axis accelerometer comprising a single substrate on which an x-axis accelerometer for detecting translation in the x-axis, a y-axis accelerometer for detecting translation in the y-axis, and a z- A method of manufacturing an inertial measurement system, wherein the x-axis accelerometer, the y-axis accelerometer, and the z-axis angle meter are formed by a surface / bulk micromachining (SBM) process, And forming a release prevention pattern that prevents the release of the release force when the release force is released.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a three-axis inertia measurement system and a three-axis inertia measurement system using the same,

The present invention relates to a method of manufacturing a three-axis inertia measurement system and a three-axis inertia measurement system using the same, and more particularly, a method of manufacturing a three-axis inertia measurement system capable of preventing a MEMS structure from being affected by a mechanical impact applied to a released MEMS and causing a failure to break or fall off, and a three-axis inertia measurement system using the same .

As a prior art, Sangwoo Lee et al., &Quot; The Surface / Bulk Micromachining (SBM) Process: A new method for fabricating released MEMS in single crystal silicon ", Journal of Microelectromechanical systems, Vol. 8, No. The Surface / Bulk Micromachining (SBM) process and the (111) silicon crystallography, which were introduced in U.S. 4, 1999, will be briefly described.

To understand the salient features of the SBM process, consider six {111} planes on a (111) oriented silicon wafer. These {111} planes represent six of the eight {111} planes, and the remainder are the top plane and the bottom plane. These six {111} planes are inclined ± 19.47 degrees from the vertical. The eight {111} planes are planes that are slowly etched in an alkaline etchant and are used as etch stops when manufacturing released structures.

The fast etch plane of (111) silicon in the alkali etchant is the {110} plane. These have a total of twelve {110} planes. Six are found by rotating equilateral triangles by 30 degrees clockwise or counterclockwise, and this {110} plane is at 90 degrees to the (111) plane. Six additional {110} planes are aligned in the (111) plane. These {110} planes are tilted by vertical and ± 54.7 degrees. These six {110} planes perpendicular to the (111) plane are the fastest etch planes. All other {100} planes as well as the other six {110} planes are etched more slowly due to the various intersecting {111} planes. In potassium hydroxide, the etch selectivity between the {110} plane of fast etch vertical and the {111} plane of slow etch is in the order of 100.

Referring to the manufacturing steps of the SBM process, a PECVD oxide layer is deposited and patterned. Next, a vertical silicon reactive ion etching (RIE) process is used to define the structural pattern. The first oxide layer should be thick enough to withstand the final aqueous alkaline etching as well as vertical silicon RIE for structural patterning and sacrificial-gap definition. Then, a second PECVD oxide film is deposited. This film is used to protect the side walls of the structure in alkali etching. The first oxide layer is anisotropically etched using RIE to leave the silicon exposed directly at the bottom of the etch trench. This step does not require a photoresist / etch process and should not etch the sidewalls. The silicon wafer is then vertically etched again using deep silicon RIE (deep silicon RIE). This is the same concept as the oxide sacrificial layer in surface micromachining. Finally, the wafer is immersed in an aqueous alkali solution, such as potassium hydroxide, ethyleene diamine pyrocatechol, or tetramethylammonium hydroxide, to perform a sacricifial etch. In this last step, the lower portion of the sidewall will be etched laterally without oxidation passivation. Such wet etching is terminated when the etching fronts meet the {111} plane. This results in released patterns. If the required release etch time is long, a nitride film can be used with the PECVD oxide film.

As noted above, the last step in the SBM process is alkali etching. The structure is flattened while the etching proceeds along the (111) direction. The reaction process is as follows. That is, a typical etchant for anisotropic wet etching is an alkaline hydroxide base, i.e., potassium hydroxide, ethiylene diamine pyrocatechol, or tetramethylammonium hydroxide (TMAH). The order of the reactions is as follows:

to be.

At this time, there was a concern that a MEMS (released MEMS) in which hydrogen gas (H2) released was subjected to a mechanical shock while being affected by the MEMS structure may be damaged or broken.

On the other hand, Korean Unexamined Patent Publication No. 2002-0079040 (published on October 19, 2002, entitled " Insulation Method for Single Crystal Silicon Microelectronic System Using Sanyo Structure, An electrode capable of supporting a floating structure can be implemented in this portion by forming an insulating layer selectively buried in a portion where electrodes are formed to implement a partial SOI structure, According to the insulation method of the present invention, selective SOI is introduced into the electrode portion by using a single crystal silicon wafer, and the same effect as that of using an expensive SOI wafer can be obtained, and furthermore, Unlike the conventional insulating method using a wafer, even in a single-crystal silicon wafer, And the position and the thickness of the insulating layer itself can be adjusted. Also, in the present invention, since the electrode is supported by the buried insulating layer realized with a desired depth and a desired thickness, the mechanical reliability is excellent and the parasitic capacitance Quot; is relatively small, and a mesa-type electrode can be realized. "

Although the SBM process has been disclosed in this patent document, the MEMS structure is affected while mechanical impact is applied to the released MEMS (released MEMS) in which hydrogen (H2) gas released in the alkali etching step, which is the last step of the SBM process, There is no sense of concern that there is a possibility of an error that causes the user to fall off.

Korean Unexamined Patent Publication No. 2002-0079040 (published on October 19, 2002, entitled: Isolation Method for Single Crystal Silicon Microelectronic System Using an Optional Sioe Structure)

Sangwoo Lee et al., &Quot; The Surface / Bulk Micromachining (SBM) Process: A New Method for fabricating released MEMS in single crystal silicon ", Journal of Microelectromechanical systems, Vol. 8, No. 4, 1999

SUMMARY OF THE INVENTION The present invention has been made in order to overcome the above-described problems, and it is an object of the present invention to provide a MEMS structure, in which a mechanical impact is applied to a MEMS (released MEMS) Axis inertia measurement system and a three-axis inertia measurement system using the same, which are capable of preventing an occurrence of an error that may be broken or broken due to the influence of the three-axis inertia measurement system.

According to a first aspect of the present invention, there is provided a method of manufacturing a three-axis inertial measurement system, comprising: detecting, on a single substrate, an x-axis accelerometer for detecting a translation in the x- axis accelerometer, a y-axis accelerometer, and a z-axis angular velocity meter for detecting rotational motion in the z-axis, wherein the x-axis accelerometer, the y- And forming a release preventing pattern which is formed by a surface / bulk micromachining (SBM) process and is prevented from being released when performing alkaline etching.

It is preferable that the release preventing pattern of the x-axis accelerometer and the release preventing pattern of the y-axis accelerometer are formed at four corner portions of the structure.

In addition, it is preferable that a total of four release preventing patterns of the z-axis angular velocity meter are formed on both sides of the spring.

Preferably, the release preventing pattern of the x-axis accelerometer, the release preventing pattern of the y-axis accelerometer, and the release preventing pattern of the z-axis angular velocity meter are released upon HF etching.

On the other hand, the 3-axis inertia measurement system according to the second embodiment of the present invention is manufactured by the above-described manufacturing method of the 3-axis inertia measurement system.

According to the method for manufacturing a three-axis inertia measurement system and the three-axis inertia measurement system using the same according to the present invention,

The final step of the conventional SBM process is to prevent a MEMS (released MEMS) from releasing H2 gas generated by alkali etching from being mechanically impacted while failing to break or fall due to the influence of the MEMS structure It is possible to do.

1 is a view showing a state where a release preventing pattern is formed in a manufacturing method of a three-axis inertia measurement system according to the present invention,
Fig. 2 shows the release preventing pattern in Fig. 1,
FIG. 3 is a view showing a state in which the release preventing pattern is maintained even when alkali etching is performed in the manufacturing method of the 3-axis inertial measurement system,
4 is a cross-sectional view taken along a line A-A 'in FIG. 2, showing a state in which a release preventing pattern is removed at the time of HF etching in a manufacturing method of a 3-axis inertial measurement system, and a MEMS structure is released.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately The present invention should be construed in accordance with the meaning and concept consistent with the technical idea of the present invention.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

Hereinafter, the portions in which the present invention is not differentiated in the SBM process will not be described in the present invention.

(Embodiment 1)

1 is a view showing a state in which a release preventing pattern is formed in a manufacturing method of a three-axis inertial measurement system according to the present invention, FIG. 2 is a view showing a release preventing pattern in FIG. 1, Sectional view taken along the line A-A 'in FIG. 2, and the release preventing pattern is maintained even when alkali etching is performed in the manufacturing method of the three-axis inertia measuring system. FIG. 4 is a cross- Sectional view of a MEMS structure in which a release preventing pattern is removed at the time of HF etching in a manufacturing method of a three-axis inertia measurement system.

A method of manufacturing a three-axis inertial measurement system according to a first embodiment of the present invention is a method of manufacturing a three-axis inertial measurement system, comprising: a step of measuring, on a single substrate, an x- Axis accelerometer, the y-axis accelerometer, and the z-axis angular velocity meter are provided with a surface / bulk micromachining (SBM) Micromachining process and forming a release preventing pattern that prevents the release inhibition pattern from being released when performing alkaline etching.

As shown in FIG. 1, the release prevention pattern of the x-axis accelerometer and the release prevention pattern of the y-axis accelerometer are preferably formed at four corner portions of the structure.

As shown in FIG. 1, it is preferable that the release preventing pattern of the z axis angular velocity meter forms four on both sides of a spring. Since the z-axis is the weakest part of the spring, it is desirable to put four z-sides on both sides of the spring.

As described above, the reaction sequence in the alkali etching process, which is the last step of the SBM process,

to be. Therefore, due to the hydrogen gas generated at this time, the MEMS structure is affected by the mechanical impact applied to the released MEMS (released MEMS), and there is a possibility that the MEMS structure is broken or broken. In the present invention, As shown in the figure, it is possible to minimize the mechanical impact on the MEMS (released MEMS) by generating the hydrogen gas using the release preventing pattern.

4, the release preventing pattern of the x-axis accelerometer, the release preventing pattern of the y-axis accelerometer, and the release preventing pattern of the z-axis angular velocity meter are different from each other in the case of HF etching .

(Second Embodiment)

On the other hand, the 3-axis inertia measurement system according to the second embodiment of the present invention is manufactured by the manufacturing method of the 3-axis inertia measurement system described in the first embodiment.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood that various modifications and changes may be made without departing from the scope of the appended claims.

10 ... release prevention pattern

Claims

A three-axis inertial measurement system in which an x-axis accelerometer for detecting translation in the x-axis, a y-axis accelerometer for detecting translation in the y-axis, and a z-axis angular velocity meter for detecting rotational motion in the z- As a production method,
The x-axis accelerometer, the y-axis accelerometer, and the z-axis angular velocity meter are formed by a surface / bulk micromachining (SBM)
Forming a release preventing pattern to prevent release when the substrate is subjected to alkaline etching.
A method of manufacturing a three-axis inertia measurement system.

The method according to claim 1,
Wherein the release preventing pattern of the x-axis accelerometer and the release preventing pattern of the y-axis accelerometer are formed at four corners of the structure,
A method of manufacturing a three-axis inertia measurement system.

The method according to claim 1,
Wherein the release preventing pattern of the z-axis angular velocity meter is formed of four on each of two sides of the spring,
A method of manufacturing a three-axis inertia measurement system.

The method according to claim 2 or 3,
Wherein the release preventing pattern of the x-axis accelerometer, the release preventing pattern of the y-axis accelerometer, and the release preventing pattern of the z-axis angular velocity meter are released at the time of HF etching,
A method of manufacturing a three-axis inertia measurement system.

A three-axis inertial measurement system manufactured by the method of manufacturing a triaxial inertial measurement system according to any one of claims 1 to 4.