WO2015176606A1

WO2015176606A1 - Method for manufacturing mems mass block

Info

Publication number: WO2015176606A1
Application number: PCT/CN2015/078242
Authority: WO
Inventors: 荆二荣; 夏长奉
Original assignee: 无锡华润上华半导体有限公司
Priority date: 2014-05-19
Filing date: 2015-05-05
Publication date: 2015-11-26
Also published as: CN105084302A

Abstract

A method for manufacturing an MEMS mass block comprises the steps of: providing a substrate (100) and a base plate (200); forming a recessed portion (300) on the substrate (100) or the base plate (200); bonding the base plate (200) and the substrate (100) to obtain an accommodating cavity (500) formed by the recessed portion (300) at a bonding interface; reducing the thickness of the base plate (200); and forming a plurality of release holes (600) at corresponding positions in the accommodating cavity (500) of the base plate (200), wherein the plurality of release holes (600) forms the profile and a support beam (800) of a mass block (900), and the mass block (900) in the profile and the base plate (200) outside the profile are connected by means of the support beam (800). The method does not need a process of removing a sacrificial layer, and the problem of adhesion between the mass block and the substrate is solved.

Description

MEMS quality block manufacturing method

[Technical Field]

The present invention relates to the field of semiconductor device technologies, and in particular, to a method for fabricating a MEMS mass.

【Background technique】

MEMS (Micro Electro Mechanical Systems, Microelectromechanical systems are micro-integrated systems that use integrated circuit fabrication techniques and micromachining techniques to fabricate microstructures, microsensors, microactuators, control processing circuits, and even interfaces, communications, and power supplies on one or more chips. With MEMS Technology development, using MEMS Technically produced accelerometers and gyroscopes have been widely used in the automotive and consumer electronics sectors. The basic structure of the accelerometer and gyroscope includes a movable mass, and the large movable mass can increase the sensitivity of the device and reduce noise interference. MEMS The preparation of movable mass has become one of the key technologies for the development and practical application of MEMS devices, thus developing a variety of MEMS. Preparation technology of movable mass. Surface micromachining techniques often make movable masses through polysilicon and sacrificial layers, which is easy to implement with CMOS The integration of the circuit, but the manufacturing quality is relatively small, the mechanical noise is large, which limits the improvement of the sensor performance. At the same time, when the method removes the sacrificial layer, the adhesion problem between the movable mass and the substrate is prone to occur, which affects the stability of the process.

[Summary of the Invention]

Based on this, it is necessary to provide a method for fabricating a MEMS mass with high process stability.

A method for fabricating a MEMS mass block includes the steps of:

A substrate and a substrate are provided.

A recess is formed on one of the substrate and the substrate.

Bonding the substrate to the substrate causes the recess to form a cavity at the interface of the bond.

The substrate is subjected to a thinning treatment.

Forming a plurality of release holes at a cavity corresponding to the substrate, the plurality of release holes forming a profile of the mass and a support beam, the mass within the profile and the substrate outside the profile passing through the support Beam connection.

The method for fabricating the above MEMS mass block does not require a final sacrificial layer removal process, avoids the problem of adhesion of the movable mass to the substrate, and improves process stability and product yield.

[Description of the Drawings]

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present invention, and those skilled in the art can obtain drawings of other embodiments according to the drawings without any creative work.

1 is a flow chart of a method of fabricating a MEMS mass of an embodiment;

Figure 2 is a plan view of a substrate of an embodiment;

Figure 3 is a side cross-sectional view taken along line A-A' of Figure 2;

Figure 4 is a side cross-sectional view of the substrate and the substrate after bonding;

Figure 5 is a plan view of the substrate and the substrate after forming the release holes;

Figure 6 is a side cross-sectional view taken along line B-B' of Figure 5 .

【detailed description】

In order to facilitate the understanding of the present invention, the present invention will be described more fully hereinafter with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the understanding of the present disclosure will be more fully understood.

All technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. The terminology used in the description of the present invention is for the purpose of describing particular embodiments and is not intended to limit the invention. The term "and/or" used herein includes any and all combinations of one or more of the associated listed items.

The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

FIG. 1 is a flow chart of a method for fabricating a MEMS mass according to an embodiment. Please refer to FIG. 2 to FIG. 6.

A method of fabricating a MEMS mass includes:

Step S100: Providing a substrate 100 and a substrate 200, which in the present embodiment is glass, and in other embodiments may also be a semiconductor material such as silicon. The substrate 200 is also a semiconductor material such as silicon in this embodiment.

Step S110: Referring to FIGS. 2 and 3, a quadrangular recess 300 is formed on the front surface of the substrate 100. The size and depth of the recess 300 on the substrate 100 depend on the specific performance requirements of the device, such as sensitivity, noise, and the like of the device. The area of the recess 300 should be smaller than the area of the substrate 200, ensuring that the substrate 200 has sufficient contact faces with the substrate 100 for bonding. The depth of the recess 300 ranges from 1 μm to 100 μm.

Step S120: As shown in FIG. 4, the bottom surface of the substrate 200 is bonded to the front surface of the substrate 100 such that the recess 300 forms a cavity 500 at the bonded interface 400. The bonding method includes electrostatic bonding or glass paste bonding to ensure that the substrate 200 can be fixed on the substrate 100 for subsequent processing.

Step S130: The front side of the substrate 200 is subjected to a thinning process, and finally the remaining thickness of a portion of the substrate in the region above the cavity 500 is equal to the thickness of the desired mass. The method of thinning treatment includes wet etching, dry etching, mechanical thinning, etc., for example, using KOH Or TMAH thins the front side of the substrate 200.

Step S140: As shown in FIG. 5 and FIG. 6, a plurality of release holes 600 are formed on a portion of the substrate in the upper region of the cavity 500 by a wet etching method and a dry etching method, and the plurality of release holes 600 are penetrated through the substrate 200, and two The two connections form a profile 700 of a mass 900 (in this embodiment a quadrilateral) and a corresponding support beam 800, the mass 900 within the profile 700 and the substrate outside the profile 700 being joined by a support beam 800.

In other embodiments, a recess may be formed on the bottom surface of the substrate 200, and then the bottom surface of the substrate 200 may be bonded to the front surface of the substrate 100, and then the substrate 200 may be thinned and etched.

The above method adopts a bonding method to prepare a movable mass, and a movable mass is prepared by using a polysilicon and a sacrificial layer method (the thickest is 1) Compared with μm), MEMS with thickness greater than 100μm can be prepared by this method. The movable mass, the large movable mass will greatly improve the sensitivity of the acceleration sensor and the gyroscope, and at the same time reduce the noise interference of the device. In addition, the method does not require a final sacrificial layer removal process, avoiding adhesion of the movable mass to the substrate, improving process stability and product yield.

It should be understood that although the various steps in the flowchart of FIG. 1 are sequentially displayed as indicated by the arrows, these steps are not necessarily performed in the order indicated by the arrows. Except as explicitly stated herein, the execution of these steps is not strictly limited, and may be performed in other sequences. Moreover, at least some of the steps in FIG. 1 may include a plurality of sub-steps or stages, which are not necessarily performed at the same time, but may be executed at different times, and the order of execution thereof is not necessarily This may be performed in sequence, but may be performed alternately or alternately with other steps or at least a portion of the sub-steps or stages of the other steps.

It can be understood that the above-mentioned manufacturing method of the MEMS mass block only describes some main steps, and does not represent all the steps of the manufacturing method of the MEMS mass. The illustrations in Figures 2-6 are also a simple example of some of the main structures of the device during fabrication of the MEMS mass and do not represent the overall structure of the device.

The above-mentioned embodiments are merely illustrative of several embodiments of the present invention, and the description thereof is more specific and detailed, but is not to be construed as limiting the scope of the invention. It should be noted that a number of variations and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, the scope of the invention should be determined by the appended claims.

Claims

A method for fabricating a MEMS mass block, comprising the steps of:

Providing a substrate and a substrate;

Forming a recess on one of the substrate and the substrate;

Bonding the substrate and the substrate such that the recess forms a cavity at the interface of bonding;

Thinning the substrate; and

Forming a plurality of release holes at a cavity corresponding to the substrate, the plurality of release holes forming a profile of the mass and a support beam, the mass within the profile and the substrate outside the profile passing through the support Beam connection.
The method according to claim 1, wherein a recess is formed on said substrate, said recess having an area smaller than an area of said substrate.
The method according to claim 1, wherein the concave portion is 1 μm to 100 μm deep.
The method of claim 1 wherein the material of the substrate comprises one of glass and a semiconductor material.
The method of claim 1 wherein the material of the substrate comprises a semiconductor material.
The method of any of claims 4 or 5 wherein the semiconductor material is silicon.
The method of claim 1 wherein said recess is quadrangular.
The method of claim 1 wherein the bonding is carried out by electrostatic bonding or glass paste bonding.
The method of claim 1 wherein the manner of thinning treatment comprises wet etching, dry etching, and mechanical thinning.
The method of claim 1 wherein said plurality of relief holes are formed by wet etching and dry etching.