CN105036060A

CN105036060A - MEMS device and manufacturing method thereof

Info

Publication number: CN105036060A
Application number: CN201510365845.5A
Authority: CN
Inventors: 王文婧; 郭群英; 黄斌
Original assignee: No 214 Institute of China North Industries Group Corp
Current assignee: No 214 Institute of China North Industries Group Corp
Priority date: 2015-06-29
Filing date: 2015-06-29
Publication date: 2015-11-11

Abstract

The invention relates to an MEMS device. The MEMS device comprises an MEMS device top electrode (2), a thermal insulating structural layer (1) and an MEMS device bottom electrode (3); a silicon pillar (3b) is arranged in the MEMS device bottom electrode (3); the lower end of the silicon pillar is correspondingly bonded and connected to an anchor point (2b) in the MEMS device top electrode (2), while the upper end of the silicon pillar is connected with a metal lead (4) in the MEMS device bottom electrode (3), and therefore, vertical wire drawing is realized. The MEMS device can be produced according to the steps of a manufacturing method provided in the invention by use of the existing technology; under the circumstance of not changing the device structure, an independent isolation structure is added to achieve the effects of effectively reducing thermal stress and improving the properties of the device; the thermal isolation structure is simple and easy to manufacture, and can be directly bonded to the device layer after being manufactured, and therefore, the reliability and device properties of a packaged product can be greatly improved; the vertical wire drawing of the device is realized to enable chip volume reduction, stray capacitance reduction, and higher transmission rate and low power consumption.

Description

A kind of MEMS and preparation method thereof

Technical field

The present invention relates to a kind of MEMS and preparation method thereof, specifically, relate to a kind of MEMS and the manufacturing process that adopt heat insulation structure and silicon post lead-in wire.

Background technology

In the face of the development trend that more and more less, the integrated difficulty of chip size is more and more higher, disk size is increasing, high-precision MEMS advantage is more obvious.Thermal stress has considerable influence to the mechanical property of MEMS, reliability and life-span.Thermal stress extensively exists with encapsulation and multilayer device.Package thermal stress is the one of the main reasons causing MEMS to lose efficacy, thermal stress is mainly from paster technique and bonding technology, in the former, the elastic modelling quantity of the thermal coefficient of expansion of substrate and Heraeus, thermal coefficient of expansion and thickness are the principal elements of package thermal stress, and in the latter, substrate and bonding temperature major effect are to the size of thermal stress.In a package, compared with direct paster to tube shell bottom, MEMS bottom surface heat of linkage isolation structure is attached to tube shell bottom package thermal stress again and can greatly reduces.Thermal stress is also the one of the main reasons of MEMS sandwich construction Interface Crack Fatigue, and under the effect of thermal stress, crackle is easily along interface Directional Extension; Temperature amplitude raises, and Fatigue Propagation of Cracks speed exponentially relation increases, and finally causes layering to be lost efficacy; By carrying out simulation analysis, experimental verification to the impact of thermal stress, result shows that thermal stress isolation structure can reduce the impact of temperature on device performance greatly.

In the prior art, the stress brought due to heat transfer causes very large impact to device performance, and device performance is generally low.Existing Patents is all make the method for heat insulation structure at device layer in conjunction with sensitive part, and manufacture craft is comparatively complicated.

In the prior art, existing employing silicon post carries out the Patents of vertical leads or stresses filling mode or utilize whole soi wafer to carry out through hole making.

Summary of the invention

Shortcoming is there is, a kind of MEMS provided and preparation method thereof exactly in object of the present invention in order to overcome in prior art.Namely the present invention realizes the problem of device architecture perpendicular interconnection to solve thermal stress to device performance impact.The present invention is in conjunction with silocon-silicon linkage technology, adopt and carry out Si-Si bonding based on SOI silicon post as the electrode material of sensor construction and top electrode and realize device architecture, thermal stress isolation structure and MEMS structure are carried out Si-Si bonding, form three layers of complete silicon structure, thus reach the object improving MEMS performance, improve yield rate.

The technical solution used in the present invention is as follows:

A kind of MEMS, comprise MEMS top electrode, the bottom surface bonding heat insulation structural layer of MEMS top electrode, the bonding MEMS bottom electrode above of MEMS top electrode, it is characterized in that: in MEMS bottom electrode, be provided with one group of silicon post with insulation system, silicon post lower end bonding corresponding to the anchor point in MEMS top electrode connects, make the metal lead wire be connected with silicon post in the oxygen buried layer of MEMS bottom electrode top layer, described each silicon post upper end is corresponding with the metal lead wire in device architecture bottom electrode to be connected.

Present invention also offers a kind of preparation method of MEMS, it is characterized in that comprising the following steps:

A. the making of heat insulation structural layer: the shallow chamber of photoetching making in the middle part of double-polished chip, four turnings of double-polished chip silicon substrate form bonding face, the movable member in the corresponding MEMS top electrode in position in shallow chamber;

The making of b.MEMS device bottom electrode: make shallow chamber, bonding face and silicon post on soi wafer, make etching mask layer, dark annular groove etching is carried out until the oxygen buried layer of soi wafer along the silicon post face of cylinder, form silicon rod structure, make electric isolution insulating barrier on the surface of dark annular groove and silicon post, finally in dark annular groove, fill filler;

The making of c.MEMS device top electrode: by the bonding face at four of the silicon substrate of heat insulation structure layer turnings and employing soi wafer bonding, etch this soi wafer substrate layer and oxygen buried layer, release movable structure forms movable structure, anchor point, forms MEMS top electrode;

D. by bonding face Si-Si bonding that MEMS top electrode is corresponding with MEMS bottom electrode, silicon post simultaneously in MEMS bottom electrode and the anchor point also Si-Si bonding in MEMS top electrode, then top layer silicon in MEMS bottom electrode is removed, oxygen buried layer is opened in photoetching, make fairlead, splash-proofing sputtering metal, photoetching making metal lead wire, alloy.

The present invention when not needing to change device architecture, by add one independently isolation structure reach and effectively reduce thermal stress, improve the effect of device performance; This heat insulation structure is simple, be easy to processing, after completing directly and device layer bonding, substantially increases reliability and the device performance of encapsulating products.The present invention is directed to double-polished chip making silicon post lead-in wire to improve for the technique of MEMS structure, use soi wafer instead to carry out making silicon post and go between for MEMS, realize device vertical leads, its advantage: reduce chip volume, reduce parasitic capacitance, higher transfer rate and low-power consumption.

Accompanying drawing illustrates:

Fig. 1 is the sectional view of heat insulation structure layer;

Fig. 2 is the top view of Fig. 1;

Fig. 3 is the soi wafer sectional view that MEMS bottom electrode adopts;

Fig. 4 is the sectional view that MEMS bottom electrode makes shallow chamber, silicon post and bonding point;

Fig. 5 is the sectional view making dark annular groove in MEMS bottom electrode;

Fig. 6 is the sectional view making dark annular groove electric isolution insulating barrier in MEMS bottom electrode;

Fig. 7 is the sectional view making dark annular groove filler in MEMS bottom electrode;

Fig. 8 is the sectional view of heat insulation structure layer and the soi wafer bonding making MEMS top electrode;

Fig. 9 be MEMS top electrode by process meanses such as photoetching, the movable structure of formation, the sectional view of anchor point;

Figure 10 is the sectional view of MEMS bottom electrode and MEMS structure structure sheaf bonding;

Figure 11 is the sectional view that MEMS bottom electrode removes top layer silicon;

Figure 12 is the sectional view at MEMS bottom electrode oxygen buried layer photoetching making fairlead;

Figure 13 is the metal lead wire sectional view through means formation such as photoetching after splash-proofing sputtering metal layer.

Detailed description of the invention

Below in conjunction with accompanying drawing, device architecture of the present invention and manufacture method are described further.

1. the making of heat insulation structure layer 1: make shallow chamber in double-polished chip as shown in Figure 1 and Figure 2, the movable member of the position respective devices layer of shallow chamber 1a; Meanwhile, only bonding face 1b being set at four turnings of double-polished chip substrate silicon in order to reduce heat biography by passing, reducing bonding area as far as possible, while guaranteeing device reliability, additionally reducing heat trnasfer.

The making of 2.MEMS device bottom electrode 3: select soi wafer as shown in Figure 3, MEMS bottom electrode makes shallow chamber as shown in Figure 4, makes etching mask layer, carries out deep etching, forms silicon post 3b structure, silicon post bonding corresponding to the anchor point of MEMS top electrode; As shown in Figure 5, Figure 6, carry out dark annular groove 3d along the silicon post 3b face of cylinder and etch until the oxygen buried layer 3e of soi wafer, form silicon post 3b structure, make electric isolution insulating barrier 3f on the surface of dark annular groove 3d and silicon post 3b, finally in dark annular groove, fill filler 3h; Finally fill dark annular groove as shown in Figure 7;

Mask layer general wet method growth silica, fill dark annular groove and can adopt teos, lpcvd, plating etc., can fill polysilicon, silica, plated metal etc., these are all existing technique.

The making of 3.MEMS device top electrode 2: heat insulation structure layer 1 and soi wafer bonding, as shown in Figure 8; Remove soi wafer substrate layer and oxygen buried layer, by means structure release such as photoetching processes, form MEMS top electrode 2, form the bonding face 2a, anchor point 2b and the movable structure 2c that are connected with oxygen buried layer 2d, as shown in Figure 9;

Removal soi wafer substrate layer and oxygen buried layer can adopt mechanical reduction and dry etching to combine, and dry etching and wet etching silica also can be adopted to combine.

4. three-decker makes: as shown in Figure 10, by MEMS top electrode 2 and MEMS bottom electrode 3 Si-Si bonding; As shown in Figure 11, Figure 12, remove the top layer silicon of MEMS bottom electrode 3, oxygen buried layer 3e is opened in photoetching, makes fairlead 4a;

As shown in figure 13,4a splash-proofing sputtering metal in oxygen buried layer 3e surface and fairlead, forms metal lead wire 4 by photoetching process, finally metal lead wire 4 is carried out alloy treatment with silicon post 3b.

Finally form complete MEMS, comprise MEMS top electrode 2, MEMS bottom electrode 3, heat insulation structural layer 1.MEMS top electrode and MEMS bottom electrode bonding, with the silicon post 3b of insulation system in MEMS bottom electrode 3, silicon post lower end connects with the corresponding bonding of anchor point 2b in MEMS top electrode, and in the oxygen buried layer 3e of MEMS bottom electrode 3 top layer, there is metal lead wire 4 at the place of opening.

Beneficial effect of the present invention: do not need the structure changing device portions in process, heat insulation structure is simple, does not need to change device architecture, direct and device layer bonding after completing, fuel factor can be reduced affect device performance, substantially increase the device performance of encapsulating products; Adopt based on the electrode material of SOI silicon post as sensor construction, do not need to change device architecture, compare the technique adopting double-polished chip to carry out one side making silicon post pin configuration to compare, avoid CMP and electricity isolated layer oxidation technology, simplify technological process, reduce technology difficulty, substantially increase element manufacturing yield rate, realize device vertical leads, its advantage: reduce chip volume, reduce parasitic capacitance, higher transfer rate and low-power consumption; Thermal stress is down to minimum by Si-Si direct bonding.

And innovative point of the present invention is just: reduce technology difficulty by silicon post lead-in wire of the present invention, reduce chip volume, reduce parasitic capacitance, higher transfer rate and low-power consumption, greatly improve MEMS yield rate; Fuel factor degree minimizes by the combination of complete silicon structure and heat insulation structure, greatly improves device performance.

Claims

1. a MEMS, comprise MEMS top electrode (2), bottom surface bonding heat insulation structural layer (1) of MEMS top electrode, the bonding MEMS bottom electrode (3) above of MEMS top electrode, it is characterized in that: in MEMS bottom electrode (3), be provided with one group of silicon post (3b) with insulation system, silicon post lower end connects with anchor point (2b) the corresponding bonding in MEMS top electrode, the metal lead wire (4) be connected with silicon post is made in the oxygen buried layer (3e) of MEMS bottom electrode (3) top layer, described each silicon post (3b) upper end is corresponding with the metal lead wire (4) in device architecture bottom electrode (3) to be connected.

2. a preparation method for MEMS, is characterized in that comprising the following steps:

A. the making of heat insulation structural layer (1): the shallow chamber of photoetching making (1a) in the middle part of double-polished chip, four turnings of double-polished chip silicon substrate form bonding face (1b), the movable member in the corresponding MEMS top electrode in position of shallow chamber (1a);

The making of b.MEMS device bottom electrode (3): make shallow chamber (3c), bonding face (3a) and silicon post (3b) on soi wafer, make etching mask layer, dark annular groove (3d) etching is carried out until the oxygen buried layer (3e) of soi wafer along silicon post (3b) face of cylinder, form silicon post (3b) structure, make electric isolution insulating barrier (3f) on the surface of dark annular groove (3d) and silicon post (3b), finally in dark annular groove, fill filler (3h);

The making of c.MEMS device top electrode (2): by the bonding face (1b) at four turnings of the silicon substrate of heat insulation structure layer (1) and employing soi wafer bonding, etch this soi wafer substrate layer and oxygen buried layer, release movable structure forms movable structure (2c), anchor point (2a), forms MEMS top electrode (2);

D. by middle to MEMS top electrode (2) and MEMS bottom electrode (3) corresponding bonding face Si-Si bonding, silicon post simultaneously in MEMS bottom electrode (3) and the anchor point also Si-Si bonding in MEMS top electrode, then top layer silicon in MEMS bottom electrode (3) is removed, oxygen buried layer is opened in photoetching, make fairlead (4a), splash-proofing sputtering metal, photoetching making metal lead wire (4), alloy.