CN205246969U

CN205246969U - Perpendicular broach drive MOEMS micro mirror

Info

Publication number: CN205246969U
Application number: CN201521059002.4U
Authority: CN
Inventors: 张晓磊; 杜妙璇; 徐永青
Original assignee: CETC 13 Research Institute
Current assignee: CETC 13 Research Institute
Priority date: 2015-12-18
Filing date: 2015-12-18
Publication date: 2016-05-18
Anticipated expiration: 2025-12-18

Abstract

The utility model discloses a perpendicular broach drive MOEMS micro mirror relates to micro electronmechanical technical field. Including the silicon wafer, the upper and lower surface of silicon wafer is equipped with the oxide layer, and the upper surface that lies in the oxide layer of upside is equipped with the structural layer of SOI disk, two sets of comb tooth structure about being equipped with in the structural layer of SOI disk and the right SOI disk, every comb tooth structure of group are including the movable comb tooth structure that is located the upside and the fixed comb tooth structure that is located the downside, and fixed comb tooth structure fixes the upper surface in the oxide layer of upside, and movable comb tooth structure includes the movable broach that a plurality of interval set up, and fixed comb tooth structure includes the fixed broach that a plurality of interval set up. The micro mirror only adopts a slice SOI disk, has simple process, control characteristics accurate and with low costs.

Description

Vertical comb teeth drives MOEMS micro mirror

Technical field

The utility model relates to field of micro electromechanical technology, relates in particular to a kind of vertical comb teeth and drives MOEMS micro mirror.

Background technology

Along with the increase gradually of optical communication network transmission and exchange capacity, the light such as demand OADM, optical cross connectUpgrading and the development of key equipment for communication, and this with the micro-optics electric mechanical such as optical attenuator (VOA), photoswitch (OSW) isThe development interwoveness of system (MOEMS) basic device. MOEMS because of its volume little easy of integration, the response time is short and be beneficial in batchesChange the feature such as preparation, in recent years standbyly extensively paid close attention to, its type of drive has developed has electric capacity to drive that (dull and stereotyped driving, broach driveMoving), heat drives and the various ways such as magnetic driving. Wherein, vertical comb teeth drives MOEMS chip can effectively overcome dull and stereotyped driving partiallyThe deficiencies such as gyration is little, intrinsic frequency is low, have become one of focus of MOEMS chip design and process exploitation.

Tradition vertical comb teeth drives chip preparing process, generally selects two SOI disks, first ties at a slice SOI diskStructure layer forms fixed fingers structure by dark silicon etching, completes bonding subsequently with another sheet SOI disk, removes this SOI disk liningAfter end silicon, utilize dual surface lithography technique, then carry out the photoetching and dark silicon etching of movable comb structure. Because broach drives electrostatic forceDirectly related with broach gap, therefore, need to there is high-precision dual surface lithography alignment process equipment, to guarantee to determine tooth and moving between cogGap is consistent.

Utility model content

Technical problem to be solved in the utility model is to provide a kind of vertical comb teeth and drives MOEMS micro mirror, described micro mirrorOnly adopt a slice SOI disk, have technique simple, control precisely and the low feature of cost.

For solving the problems of the technologies described above, technical solution adopted in the utility model is: a kind of vertical comb teeth drives MOEMSMicro mirror, is characterized in that: comprise silicon wafer, the upper and lower surface of described silicon wafer is provided with oxide layer, is positioned at the oxide layer of upsideUpper surface is provided with the structure sheaf of SOI disk, is provided with two groups of left and right broach knot in the structure sheaf of described SOI disk and right SOI diskStructure, every group of comb structure comprises the movable comb structure that is positioned at upside and the fixed fingers structure that is positioned at downside, fixed fingers knotStructure is fixed on the upper surface of the oxide layer of upside, and movable comb structure comprises several spaced movable comb, fixing combToothing comprises several spaced fixed fingers, and described fixed fingers is relative with the space between movable comb, movably combThe lower surface of tooth and the upper surface of fixed fingers remain on same plane, and movable comb does not contact with fixed fingers; Two groups of combsBetween toothing, for micro mirror reverses space, in reversing space, micro mirror is provided with movable micro-mirror structure, described movable micro-mirror structureUpper surface is provided with speculum surface layer, and the upper surface of the structure sheaf of described SOI disk is provided with comb drive electrode.

Further technical scheme is: described silicon wafer is twin polishing silicon wafer, and thickness is 400 ± 100 μ m, SOIThe Laminate construction thickness of disk is minimum is 100 μ m.

Further technical scheme is: described speculum surface layer and comb drive electrode are chromium or gold, and the thickness of chromium is10nm-30nm, the thickness of gold is not less than 100nm.

The beneficial effect that adopts technique scheme to produce is: described micro mirror only adopts monolithic SOI disk, minute surface knotStructure and comb structure are one deck, and movable comb structure and minute surface discharge and carry out simultaneously, and technique is simple, can reduce Alternative to mirrorThe issuable impact of face quality. Twin polishing silicon wafer surface oxide layer is as isolation barrier, can effectively avoid minute surface withLower substrate contact and the short circuit phenomenon that causes, improve the stability of device.

Brief description of the drawings

Fig. 1-10th, procedure structure schematic diagram of the present utility model;

Figure 11 is micro-mirror structure schematic diagram described in the utility model;

Figure 12 is the part-structure schematic diagram of micro mirror described in the utility model;

Wherein: 1, silicon wafer 2, SOI disk 21, structure sheaf 22, intermediate oxide layer 23, substrate layer 3, broach driveElectrode 4, movable comb structure 5, fixed fingers structure 6, movable micro-mirror structure 7, speculum surface layer 8, oxide layer 9, pre-Masking graphics 10, photoetching offset plate figure.

Detailed description of the invention

Below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme in the utility model embodiment is carried out clearlyChu, intactly description, obviously, described embodiment is only a part of embodiment of the present utility model, instead of wholeEmbodiment. Based on the embodiment in the utility model, those of ordinary skill in the art are not making under creative work prerequisiteThe every other embodiment obtaining, belongs to the scope that the utility model is protected.

Set forth in the following description a lot of details so that fully understand the utility model, but this practicality is newType can also adopt other to be different from alternate manner described here and implement, and those skilled in the art can be without prejudice to this realityIn situation by novel intension, do similar popularization, therefore the utility model is not subject to the restriction of following public specific embodiment.

As shown in figure 11, the utility model discloses a kind of vertical comb teeth and drive MOEMS micro mirror, comprise silicon wafer 1, described inThe upper and lower surface of silicon wafer 1 is provided with oxide layer 8, and the upper surface that is positioned at the oxide layer 8 of upside is provided with the structure sheaf 21 of SOI disk 2,Preferably, described silicon wafer 1 is twin polishing silicon wafer, and thickness is 400 ± 100 μ m, the thickness of the structure sheaf 21 of SOI disk 2Minimum is 100 μ m. In the structure sheaf of described SOI disk, be provided with the two groups of comb structures in left and right, every group of comb structure comprises and being positioned atThe movable comb structure 4 of side and be positioned at the fixed fingers structure 5 of downside, fixed fingers structure 5 is fixed on the oxide layer 8 of upsideUpper surface, movable comb structure 4 comprises several spaced movable comb, fixed fingers structure 5 comprises several intervalsThe fixed fingers arranging, described fixed fingers is relative with the space between movable comb, the lower surface of movable comb and fixed fingersUpper surface remain on same plane, and movable comb do not contact with fixed fingers, as shown in figure 12; Between two groups of comb structuresFor micro mirror reverses space, in reversing space, micro mirror is provided with movable micro-mirror structure 6, and the upper surface of described movable micro-mirror structure 6 is establishedHave speculum surface layer 7, the upper surface of the structure sheaf of described SOI disk is provided with comb drive electrode 3. Preferably, described speculumSurface layer 6 and comb drive electrode 3 are chromium or gold, and the thickness of chromium is 10nm-30nm, and the thickness of gold is not less than 100nm.

Vertical comb teeth drives MOEMS micro mirror, can realize the deflection of the set angle of micro mirror by applying less driving voltage,Its general principle is (wherein d represents the lateral separation between movable comb and fixed fingers) as shown in figure 12, fixed fingers structure 5Be connected with one of them comb drive electrode 3, movable comb structure 4 is connected with another comb drive electrode 3, when fixingBetween comb structure and movable comb structure, apply after voltage, revolve because interelectrode electrostatic force makes the movable micro-mirror structure axis that lingersTurn, thereby drive micro mirror deflection mirror surface, until electrostatic force moment of torsion and turning round that the torsion beam restoring force in movable micro-mirror structure producesWhen square equates, micro mirror is realized stable, is therefore that the deflection of different angles is with steady by applying different voltage, can realizing diverse locationFixed. Formula (1) is broach driving electrostatic force formula.

（1）

Wherein, ε is permittivity of vacuum, and N is movable comb quantity, and l is broach length, and v is fixed fingers and movable combThe voltage that between cog applies, d is fixed fingers and movable comb gap.

Can be found out by formula (1), electrostatic force and broach quantity and length, apply voltage and surely moving broach gap is relevant, justSet design chips, electrostatic force is directly limited to the technical process control in fixed fingers and movable comb gap, to guarantee staticPower stabilization is in broach and minute surface.

The preparation method of above-mentioned MOEMS micro mirror comprises the steps:

1) at the upper surface coating photoresist of the structure sheaf 21 of SOI disk 2, exposure, develop after in the structure of SOI disk 2Layer 21 forms the pre-figure of fixed fingers, forms the pre-structure of fixed fingers and micro mirror torsion after dark reaction and plasma etching DRIESpace, as shown in Figure 1.

2) silicon wafer 1 is oxidized, lower surface forms oxide layer 8 thereon, and silicon wafer 1 adopts twin polishing silicon circleSheet, thickness is generally 400 μ m; The drives structure layer thickness of SOI disk is minimum is 100 μ m.

3) silicon wafer after oxidation 1 and the drives structure layer 21 of SOI disk 2 upper surfaces are carried out to Si-Si bonding, as Fig. 2 instituteShow;

4) adopt reactive ion etching RIE and body silicon wet corrosion technique to remove substrate layer 23 and the middle oxygen of SOI disk 2Change layer 22;

5) by above-mentioned device upset, as shown in Figure 3, the upper surface of the device after upset is prepared metal level, metal level oneAs be chromium or gold, the thickness of chromium is generally 10nm-30nm, gold thickness be generally not less than 100nm; In metal level coating photoetchingAfter glue, exposure, development, then form comb drive electrode 3 and metallic reflection minute surface 7 through etching process, as shown in Figure 4;

6) pass through plasma enhanced chemical gas phase PECVD cvd silicon oxide film at the upper surface of above-mentioned device, asMasking layer;

7) in masking layer surface coating photoresist, photoetching, development described in step 6), after thin film corrosive, form movable combThe pre-masking graphics 9 of tooth, as shown in Figure 5;

8) the pre-masking graphics surface forming in step 7), continues coating photoresist, forms movable comb after photoetching, developmentTooth, torsion beam and micro mirror minute surface figure, as shown in Figure 6, thin film corrosive is removed the unprotected masking layer of photoresist, as shown in Figure 7;

9) on the patterned surface forming in step 8), carry out dark reaction and plasma etching DRIE technique, do not have photoresist to protectThe region of protecting, etching forms movable comb structure 4, torsion beam and movable micro-mirror structure 6 vertically downward, and etching depth is no more than 30μ m, the lower surface of movable comb structure 4 and the upper surface of fixed fingers structure 5 that etching forms remain on same plane, as Fig. 8Shown in; After removing photoresist, (as shown in Figure 9) continuation etching, in the region that there is no masking layer protection, continues vertical etching, by fixed fingersStructure 5 comes out, and as shown in figure 10, forms described MOEMS micro mirror, as shown in figure 11 after erosion removal masking layer.

Described method, by reserved masking layer, in conjunction with photoetching, corrosion and twice dark silicon etching process, can precisely be controlled fixingThe interstructural gap of comb structure and movable comb. Only adopt monolithic SOI disk, mirror surface structure and comb structure are one deck, canMoving comb structure and minute surface discharge and carry out simultaneously, and technique is simple, can reduce Alternative to the issuable impact of mirror-quality.Twin polishing silicon wafer surface oxide layer is as isolation barrier, can effectively avoid minute surface and lower substrate contact and the short circuit that causesPhenomenon, the stability of raising device.

Claims

1. vertical comb teeth drives a MOEMS micro mirror, it is characterized in that: comprise silicon wafer (1), described silicon wafer (1) upper and lowerSurface is provided with oxide layer (8), and the upper surface that is positioned at the oxide layer (8) of upside is provided with the structure sheaf (21) of SOI disk (2), described inIn the structure sheaf of SOI disk, be provided with the two groups of comb structures in left and right, every group of comb structure comprises the movable comb structure that is positioned at upsideAnd be positioned at the fixed fingers structure (5) of downside (4), fixed fingers structure (5) is fixed on the upper surface of the oxide layer (8) of upside,Movable comb structure (4) comprises several spaced movable comb, and fixed fingers structure (5) comprises that several intervals arrangeFixed fingers, described fixed fingers is relative with the space between movable comb, the lower surface of movable comb and fixed fingers upperSurface remains on same plane, and movable comb does not contact with fixed fingers; Between two groups of comb structures, be micro mirror torsion space,In micro mirror reverses space, be provided with movable micro-mirror structure (6), the upper surface of described movable micro-mirror structure (6) is provided with speculum surface layer(7), the upper surface of the drives structure layer of described left SOI disk and the drives structure layer of right SOI disk is provided with comb drive electrode（3）。

2. vertical comb teeth as claimed in claim 1 drives MOEMS micro mirror, it is characterized in that: described silicon wafer (1) is two-sided throwingLight silicon wafer, thickness is 400 ± 100 μ m, structure sheaf (21) thickness of SOI disk is minimum is 100 μ m.

3. vertical comb teeth as claimed in claim 1 drives MOEMS micro mirror, it is characterized in that: described speculum surface layer (6) and combTooth drive electrode (3) is chromium or gold, and the thickness of chromium is 10nm-30nm, and the thickness of gold is not less than 100nm.