TWI387555B - Mems integrated chip and method for making same - Google Patents

Description

MEMS wafer and manufacturing method thereof

The present invention relates to a microelectromechanical system wafer, and to a method of fabricating such a system wafer.

MEMS have a variety of applications, such as micro-acoustic pressure sensors, gyroscopes, accelerometers, and more. Most MEMS systems contain MEMS components and other microelectronic circuits that must be integrated with each other to form an integrated wafer. In one of the prior art, the microelectromechanical component and the microelectronic circuit are placed on the same surface of the wafer. For example, referring to the plan view of FIG. 1, as shown, the integrated wafer includes the microelectromechanical component region 100 and the microelectronic circuit. An element (e.g., CMOS element) region 200, and the microelectromechanical device region 100 is surrounded by a guard ring 120 to prevent etch damage to the microelectronic circuit device region 200 during fabrication of the microelectromechanical device.

Please refer to FIG. 2. FIG. 2 is a cross-sectional view taken along line A-A of FIG. 1. In the process of fabricating the microelectronic circuit component and the microelectromechanical component, a plurality of dielectric layers 19 (without dividing the boundaries between the layers) are deposited on the substrate 11, and in this prior art, etching must be performed. The dielectric layer 19 forms a movable microelectromechanical element (not shown) in the microelectromechanical element region 100, thus leaving a space 10 in the microelectromechanical element region 100. As described above, when the dielectric layer 19 is etched, the microelectronic circuit device region 200 is not damaged. Therefore, the guard ring 120 is provided, which is composed of the polysilicon layer 12, the metal layers 15, 16, 17 and 18, and the dielectric layer 19. The number of metal layers can be determined by the wiring requirements within the microelectronic circuit and the design of the MEMS components.

In order to fabricate microelectromechanical components and microelectronic circuit components on the same surface, electrical connections must be provided therebetween. In the above prior art, one or more layers are used. A layer of metal is used to achieve this bond, such as the second metal layer 16 in FIG. However, since one or more layers of metal are used, the layers must pass through the guard ring 120 and will not be able to interact with other portions of the guard ring 120 (the first contact layer in the illustration) at the location through which the guard ring 120 is passed. 14. The first metal layer 15) constitutes a tightly closed structure, otherwise a short circuit is caused. Therefore, in this prior art, the damage to the microelectronic circuit component region 200 cannot be completely avoided when etching the microelectromechanical device.

In addition, in this prior art, since the microelectromechanical element and the microelectronic circuit are disposed on the same surface of the wafer, the area is relatively consumed.

In view of the above, it is necessary to provide a structure that functionally couples MEMS components to microelectronic circuit components while still protecting the integrity of the microelectronic circuit component regions and, in addition, reducing the MEMS wafer footprint. area.

It is an object of the present invention to provide a microelectromechanical system wafer that protects the integrity of the microelectronic circuit component regions and occupies less area.

Another object of the present invention is to provide a method of fabricating a microelectromechanical system wafer.

In order to achieve the above object, in one aspect of the present invention, a microelectromechanical system wafer is provided, comprising: a first substrate having opposite first and second surfaces; and a microelectronic circuit on the first surface An element region; a first MEMS element region on the second surface; and a wire structure electrically connecting the microelectronic circuit device region to the first MEMS device region.

In another aspect of the present invention, a method of fabricating a MEMS wafer is provided, comprising the steps of: providing a first substrate having a phase a first surface and a second surface; forming a microelectronic circuit component region on the first surface; forming a wire structure traversing the first substrate; forming a first MEMS element region on the second surface; The microelectronic circuit component region and the first microelectromechanical device region are electrically connected by the wire structure, wherein the step of forming the microelectronic circuit component region, forming the wire structure passing through the first substrate, and forming the first microelectromechanical device region may be In any order.

In the above MEMS wafer and manufacturing method, the first substrate may be a silicon on insulator (SOI) material.

In the above MEMS wafer and fabrication method, the wire structure may be formed by a through silicon via (TSV) method.

In the above MEMS wafer and manufacturing method, the first MEMS element region may include a moving member formed by a twin portion of the eutectic insulator material.

In the above MEMS wafer and manufacturing method, a second substrate may be further provided, and a second MEMS element region is formed on the second substrate, and the second substrate and the first substrate are bonded to make the second MEMS The component region is functionally coupled to the aforementioned first microelectromechanical component region.

The purpose, technical content, features and effects achieved by the present invention will be more readily understood by the detailed description of the embodiments.

The drawings in the present invention are schematic and are mainly intended to represent the process steps and the relationship between the layers, and the shapes, thicknesses, and widths are not drawn to scale.

The main concept of the present invention is to separately provide microelectronics on both sides of the substrate. The circuit and the microelectromechanical component are provided in a wire structure to provide a functional connection between the two. A preferred embodiment of the wire structure is a through silicon via (TSV). The steps may be: (1) first setting a microelectronic circuit, then fabricating a wire structure, and then fabricating a microelectromechanical component; (2) first setting a microelectronic circuit, then fabricating a microelectromechanical component, and then fabricating a wire structure; (3) first setting MEMS components, remanufactured wire structures, and fabricated microelectronic circuit components; (4) first set up microelectromechanical components, then fabricate microelectronic circuit components, and then fabricate wire structures; (5) first set wire structure, then fabricate microelectromechanical components And then make microelectronic circuit components; (6) first set the wire structure, then make microelectronic circuit components, and then make microelectromechanical components.

After the above steps are completed, or after the microelectromechanical component is fabricated, a coating layer may be provided to cover and seal the microelectromechanical component, and the corresponding microelectromechanical component may be disposed on the cladding layer, and the substrate may be disposed on the substrate. The interaction of the microelectromechanical components, for example, constitutes a planar sensor, and the like.

Hereinafter, the first (1) production method of the above concept will be described by way of examples. After referring to the embodiments, the person skilled in the art can be applied to the above (2) to (6) production methods.

Referring to FIG. 3 to FIG. 9 , in the embodiment, a first substrate 110 is provided as a substrate of a microelectromechanical component and a microelectronic circuit component (for example, a CMOS component). As shown in FIG. 3 , the substrate may be a germanium. Silicon on insulator, The SOI) material has a first surface 111 and a second surface 112 separated by an insulator 31 therebetween. As shown in FIG. 4, a protective layer 51 is deposited on the second surface 112 of the first substrate 110. This protective layer 51 is, for example, an undoped polysilicon layer, or other layer of material that provides electrical isolation. As shown in FIG. 5, on the first surface 111 of the first substrate 110, a microelectronic circuit device region 200a is formed, including, for example, a doped region 13a, a gate layer 12a, metal layers 15a, 16a, 17a, 18a, and A constituent layer required for a microelectronic circuit component region such as a passivation 19a, for example, a standard CMOS process can be used.

FIG. 6 illustrates the wire structure 300 of the present embodiment. In the present embodiment, the wire structure 300 is formed on the second surface 112 of the first substrate 110 by using a through-silicon via method to form a microelectromechanical component and a microelectronic circuit component. The wires are joined and the protective layer 51 is removed during the process. The through-silicone via is typically formed by etching. After the via is filled, a barrier layer 310 is filled and a conductor layer 320 is filled. The barrier layer 310 can be, for example, titanium or nitrogen. The composite structure of titanium, tantalum, tantalum nitride or the above material, the barrier layer 310 can also be regarded as an adhesion layer, because it can improve the adhesion of the conductor layer 320 and the substrate 110 in addition to the barrier function. The material of the conductor layer 320 may be a commonly used perforated conductor material such as tungsten, copper or the like. It should be noted that although the preferred embodiment of the present invention forms the wire structure 300 by using a through-pass twinning method, the manner in which the micro-electromechanical element and the micro-electronic circuit element are functionally coupled is not limited to the use of through-pass twinning, and may be other The manner is such that the connection is made through a wire bond outside the wafer, which is also within the scope of the invention.

Referring to FIG. 7, on the second surface 112 of the first substrate 110, a first MEMS element region 400 is formed by etching; the etching method depends on the substrate material and the shape of the MEMS element to be formed, when the substrate is 矽For example, you can use non An isotropic ICP (Inductively Coupled Plasma) etch, or an isotropic XeF2 etch. After the first microelectromechanical device region 400 is formed, as shown in FIG. 8, a portion of the insulating layer 31 is etched away to make the first microelectromechanical device a movable member, and the etching method thereof may be, for example, HF vapor etching or buffer oxide etching (buffered). Oxide etch). In this embodiment, the first microelectromechanical element has formed a complete microelectromechanical element, and the moving element of the microelectromechanical element is formed by a twinned portion of the crystalline insulator material. Referring next to FIG. 9, the first MEMS element region 400 is covered with a cladding layer 410 to complete the overall structure of the MEMS wafer. The cladding layer may be, for example, another tantalum substrate joined to the first substrate 110 using a glass frit, a solder, or a photo-sensitive polymer as a bonding material. The details of the combination method are not the focus of this case. Please refer to the application No. 098126099 filed by the applicant in this case on August 3, 1998, and will not be repeated here.

Next, a second embodiment of the present invention will be described. In this embodiment, after the steps of FIGS. 3-8, and then FIG. 10 and FIG. 11, a second substrate 500 is provided. The substrate can be, for example, a germanium substrate, and an electrical connection terminal is formed on the second substrate 500. 510 and a second MEMS element region 520. The purpose of the electrical connection end 510 is to make an electrical connection between the second substrate 500 and the first substrate 110 to enable the electrical signal to be transmitted, such as, but not limited to, being connectable to the wire structure 300 of the first substrate 110. The second MEMS element region 520 can be fabricated using the substrate itself, or can be formed on the substrate by deposition, lithography, or etching, using germanium, metal, and/or insulating layers. The manner in which the second substrate 500 is bonded to the first substrate 110 may be performed by any of the above methods, using glass sintering, soldering, or bonding with a photosensitive polymer as a bonding material. As shown in FIG. 11, after the first substrate 110 is bonded to the second substrate 500, the second MEMS element region 520 and the first MEMS element region 400 are A combined function can be achieved to form a complete microelectromechanical component 400a that can sense changes in motion in the vertical direction, such as an out-of-plane sensor. In a preferred embodiment, at a periphery not shown in the drawing, the microelectromechanical element 400a and the electrical connection (510, 300) are preferably sealed with a gas-tight material. The sealing step may be performed on the second substrate 500 and the first substrate 110. Completed at the time of joining, without further instructions.

The present invention has been described with reference to the preferred embodiments thereof, and the present invention is not intended to limit the scope of the present invention. For those skilled in the art, various equivalent changes can be immediately considered within the spirit of the invention. For example, the materials, the number of metal layers, and the like in the above embodiments are all exemplified, and there are other possibilities for equivalent changes. Further, the microelectronic circuit integrated with the microelectromechanical element is not limited to being fabricated by a CMOS element, and may also include a bipolar transistor or the like. Equivalent changes or modifications of the concept and spirit of the invention are intended to be included within the scope of the invention.

10‧‧‧ space

11‧‧‧Substrate

12,12a‧‧‧Polysilicon layer

13,13a‧‧‧Doped area

14‧‧‧First contact layer

15,15a‧‧‧First metal layer

16,16a‧‧‧Second metal layer

17,17a‧‧‧ third metal layer

18,18a‧‧‧Fourth metal layer

19‧‧‧Dielectric layer

19a‧‧‧ Passivation layer

31‧‧‧Insulation

51‧‧‧Protective layer

100‧‧‧Microelectromechanical component area

110‧‧‧First substrate

111‧‧‧ first surface

112‧‧‧ second surface

120‧‧‧ guard ring

200,200a‧‧‧Microelectronic circuit component area

300‧‧‧Wire structure

310‧‧‧Barrier layer

320‧‧‧ conductor layer

400‧‧‧First MEMS component area

400a‧‧‧Microelectromechanical components

410‧‧‧Cladding

500‧‧‧second substrate

510‧‧‧Electrical connection

520‧‧‧Second MEMS component area

Figures 1-2 show prior art.

Figures 3-9 illustrate a first embodiment of the present invention.

Figures 10-11 illustrate a second embodiment of the present invention.

31‧‧‧Insulation

110‧‧‧First substrate

200a‧‧‧Microelectronic circuit component area

300‧‧‧Wire structure

400‧‧‧First MEMS component area

410‧‧‧Cladding

Claims (13)

A microelectromechanical system wafer comprising: a first substrate having opposing first and second surfaces; a microelectronic circuit component region on the first surface; a first MEMS element region on the second surface; a wire structure electrically connected to the first MEMS element region, wherein the wire structure is from the second surface toward the first surface, penetrates the first substrate, and reaches the first surface, A wire structure is formed through the first substrate. The MEMS wafer of claim 1, wherein the first substrate is a twinned insulator material (SOI). The MEMS wafer of claim 2, wherein the first MEMS element region comprises a moving member formed by a twin portion of the eutectic insulator material. The MEMS wafer of claim 1, further comprising a cladding layer covering the first MEMS element region. The MEMS wafer of claim 1, further comprising a second substrate bonded to the first substrate, the second substrate comprising a second MEMS element region, and the first MEMS element region Microelectromechanical components provide a combined function. The MEMS wafer of claim 5, wherein the second substrate is electrically connected to the wire structure. A method of fabricating a microelectromechanical system wafer, comprising the steps of: providing a first substrate having opposite first and second surfaces; and forming a microelectronic circuit component region on the first surface; Forming a through hole from the second surface toward the first surface to etch through the first substrate and reaching the first surface to form a wire structure passing through the first substrate; and forming a first micro on the second surface An electromechanical component region; and electrically interconnecting the microelectronic circuit component region and the first microelectromechanical device region by the wire structure, wherein the microelectronic circuit component region is formed, the wire structure is formed through the first substrate, and the first micro is formed The steps of the electromechanical component region can be in any order. The method of fabricating a microelectromechanical system wafer according to claim 7, wherein the first substrate is a twinned insulator material. The method of fabricating a microelectromechanical system wafer according to claim 8, wherein the step of forming the first microelectromechanical device region comprises: etching a twin portion of the germanium insulator material and an insulator portion to form a movable member . The method of fabricating a microelectromechanical system wafer according to claim 7, further comprising: forming a protective layer on the second surface before forming the microelectronic circuit component region. The method for fabricating a microelectromechanical system wafer according to claim 10, further comprising: removing the protective layer on the second surface before the step of forming the through hole by etching to penetrate the first substrate, and wherein The step of forming a wire structure through the first substrate includes: filling in the barrier material; and filling in the conductor material. The method for fabricating a microelectromechanical system wafer according to claim 7, further comprising: forming a cladding layer after the first microelectromechanical component region is formed, and coating the first Microelectromechanical component area. The method for fabricating a MEMS wafer according to claim 7 , further comprising: providing a second substrate; forming a second MEMS element region on the second substrate; bonding the second substrate and the first substrate The second MEMS element region is functionally coupled to the aforementioned first MEMS element region.