CN1766684A

CN1766684A - Microminiature moving device and method of making the same

Info

Publication number: CN1766684A
Application number: CN 200510065655
Authority: CN
Inventors: 森惠一; 加藤嘉睦; 吉田惠; 近藤健治; 滨田义彦; 伊卷理
Original assignee: Japan Aviation Electronics Industry Ltd
Current assignee: Japan Aviation Electronics Industry Ltd
Priority date: 2004-03-03
Filing date: 2005-03-03
Publication date: 2006-05-03
Anticipated expiration: 2025-03-03
Also published as: CN100444317C; JP5016653B2; JP2010052134A

Abstract

In a microminiature moving device that has disposed, on a single-crystal silicon substrate, movable elements (a movable rod 46, a movable comb electrode 49, etc.) displaceable in parallel to the substrate surface and stationary parts (a stationary part 40 a, etc.), the stationary parts are fixedly secured to the single-crystal silicon substrate 61 with an insulating layer 62 sandwiched therebetween, and depressions 64 are formed in those surface regions of the single-crystal silicon substrate 61 where no stationary parts are present, and the movable parts are positioned above the depressions 64. The depressions 64 form gaps 50 large enough to prevent foreign bodies from causing troubles such as malfunction of the movable parts and shoring.

Description

Microminiature moving device and preparation method thereof

Technical field

The present invention relates to a kind of microminiature moving device that is made by micromachining technology such as photoetching, etching etc. (microminiature moving device), more particularly, relate to a kind of having and to be parallel to freely the be shifted microminiature moving device of moving-member of (freely displaceable) of substrate surface.

Background technology

The present invention relates to a kind of microminiature moving device that is made by micromachining technology such as photoetching, etching etc., more particularly, relate to a kind of microminiature moving device that can be parallel to the moving-member that substrate surface freely is shifted that has.

For instance, this microminiature moving device comprises micro optical switch, micro accelerometer and miniature relay.The SOI that the common use of these microminiature moving devices is three layers (Silicon On Insulator: silicon-on-insulator) make, and the SOI substrate comprises an insulation course that is clipped between monocrystalline silicon layer and the monocrystalline substrate by substrate.

As the example of microminiature moving device in the prior art, Fig. 1 shows United States Patent (USP) the 6th, 315, No. 462 (November 13 calendar year 2001, issue was called document 1 hereinafter) described photoswitches.Fig. 2 has provided the series of steps of making document 1 disclosed photoswitch.At first, the structure of photoswitch will be described below with reference to figure 1.

In tabular flat substrate 11 is on the top surface of SOI substrate, four optical fiber that form right-angled intersection insert raceway groove (optical fier insertion channel) 12a to 12d, be in the optical fiber that extends at the right angle

insert raceway groove

12a and 12b surround actuating mechanism (actuator) form distinguish 11 '.Form groove 13 that inserts

raceway groove

12a and 12b angle at 45 respectively with optical fiber of district's 11 ' middle formation at actuating mechanism.In groove 13, dispose motion bar 14.

One end of motion bar 14 has minute surface (mirror) 15, and it is positioned at mutual rectangular four optical fiber raceway groove 12a at first in the zone of intersection between the 12d 16.The both sides of motion bar 14 center sections are attached to the end of

brace summer

17a and 17b, and the other end of

brace summer

17a and 17b is separately fixed on fixture (stationary part) 19a and the 19b by the support member 18a and the 18b of similar springs.Similarly, among brace summer 17c and the 17d each at one end is attached to a side of neck one end of motion bar 14 relative its inners, and the other end of

brace summer

17c and 17d also is separately fixed on fixture 19a and the 19b by the support member 18c and the 18d of similar springs.Like this, the support member 18a of similar springs can vertically move motion bar 14 along it to 18d.

Motion bar 14 drives by pectination electrostatically actuated mechanism, actuating mechanism comprises and is separately fixed at the movable comb electrode 21a of brace summer 17a to the 17d to 21d, and fixedly be formed on actuating mechanism form district 11 ' in fixed comb electrode 22a to 22d, fixed comb electrode 22a is staggered to 21d is alternate with movable comb electrode 21a respectively to 22d.

The voltage that is added between

movable comb electrode

21a and 21b and fixed comb electrode 22a and the 22b produces electrostatic attraction, drives the direction of motion bar 14 to the described zone of intersection 16 and moves.On the other hand, the voltage that is added between

movable comb electrode

21c and 21d and fixed comb electrode 22c and the 22d produces electrostatic attraction, drives motion bar 14 and moves to the direction away from the zone of intersection 16.Therefore,, drive motion bar 14, can make minute surface 15 push and pull out the zone of intersection 16 by pectination electrostatically actuated mechanism by selectively applying voltage.

In 12d, dispose optical fiber 23a respectively at four raceway groove 12a to 23d.When minute surface 15 remains in the zone of intersection 16, from the light that optical fiber 23a sends, for instance, will and penetrate on optical fiber 23d from minute surface 15 reflections, the light that sends from optical fiber 23b also will and be penetrated on optical fiber 23c from minute surface 15 reflections simultaneously.When minute surface 15 is pulled out from the zone of intersection 16, will inject optical fiber 23c from the light that optical fiber 23a sends, the light that sends from optical fiber 23b also will be injected optical fiber 23d simultaneously.Like this, just realized the switching of light path.

Fig. 2 provided make described traditional photoswitch series of steps S1 to S3.Making is prepared SOI substrate 30 from step S1, and it comprises the silicon dioxide (SiO that is clipped between monocrystalline silicon layer 33 and the monocrystalline substrate 31 ₂) insulation course 32, subsequently by forming the mask 34 of required pattern on the surface that is patterned at whole monocrystalline silicon layer 33.Then, in step S2, utilize reactive ion etching (RIE) and etch away the surface of monocrystalline silicon layer 33 selectively, on whole insulation course 32, stay desired pattern up to insulation course 32 by mask 34.

Thin slice 35 correspondences of the monocrystalline silicon layer 33 that forms in step S2 movable part, motion bar 14 for example shown in Figure 1, minute surface 15, brace summer 17a to the element 18a of 17d, similar springs to 18d and movable comb electrode 21a to 21d, be fixed on fixed part on the monocrystalline substrate 31 and sheet 36 will finally form

fixed part

19a, 19b shown in Figure 1 and other.Movable part among Fig. 2 and fixed part are exemplary illustration.

Then, in step S2, the insulation course 32 that exposes is carried out wet etching, the insulation course below being in thin slice 35 is removed by the side etching.So, thin slice 35 being suspended on like that slightly on the monocrystalline substrate 31 shown in 37 among the step S3 just; That is, the movable part that is made of thin slice 35 separates from monocrystalline substrate 31 by removing insulation course 32 selectively, thereby they can move freely.On the both side surface of the thin slice 35 of the monocrystalline silicon layer 33 that is used for forming minute surface 15, plate reflective film.

In method for making shown in Figure 2, etch away the insulation course 32 of the SOI substrate 30 under the movable part that monocrystalline silicon layer 33 is constituted, thereby movable part can be shifted.

As mentioned above, this microminiature moving device that has the movable part that can be parallel to the substrate surface displacement, usually use SOI substrate 30 to make, and etch away intermediate insulating layer 32 selectively, thereby form all movable parts (thin slice 35), each movable part separates by minim gap and following monocrystalline substrate 31.

Because it is thick that the intermediate insulating layer 32 common maximums of SOI substrate 30 are about 3 μ m, so the gap between movable part (thin slice 35) and the monocrystalline substrate 31 is very little, to such an extent as to the operate as normal of the foreign matter of the minimum in the gap also there is a strong possibility interfering activity parts.

In addition, when the insulation course 32 below movable part (thin slice 35) is etched away, insulation course 32 below fixed part (sheet 36) also can be removed by the side etching, thereby fixed part (sheet 36) and below monocrystalline substrate 31 between form the gap, the width in the etching gap, insulation course 32 side below its width and the movable part (thin slice 35) is the same; Therefore, foreign matter also can enter these gaps sometimes.In this case, a worry being arranged is that foreign matter can make monocrystalline substrate 31 and fixed part (sheet 36) short circuit---situation of fixed part (sheet 36) short circuit may take place to make by foreign matter and monocrystalline substrate 31 once in a while for this.

Therefore, traditional microminiature moving device has the defective of accidental short circuit, thereby makes two defectives that fixed part breaks down that apply voltage as electrode to pectination electrostatically actuated mechanism.

Summary of the invention

Therefore an object of the present invention is to provide a kind of microminiature moving device, it can use the SOI substrate to make, and can eliminate the described problem that exists in the prior art.

Another object of the present invention provides a kind of method of making this microminiature moving device.

According to the present invention, the microminiature moving device that is provided is included in the movable part and the fixed part of the be parallel to monocrystalline substrate surface displacement that forms on the monocrystalline substrate, and wherein: fixed part is fixed on the monocrystalline substrate by the insulation course that is clipped between it and the monocrystalline substrate; Form depression on the surface of the monocrystalline substrate that does not have fixed part to form, movable part is formed on the top of depression.

According to the present invention, a kind of method of making described microminiature moving device is provided, it may further comprise the steps: form mask layer on the top surface of the whole monocrystalline silicon layer of three layers of SOI substrate, the SOI substrate comprises an insulation course that is clipped between monocrystalline substrate and the monocrystalline silicon layer; The patterned mask layer forms the mask of fixed part and the mask of the movable part that is made of narrow combinations of patterns; Utilize the gas reaction dry etching and optionally etch away monocrystalline silicon layer, up to exposing insulation course by mask; Use the sidewall diaphragm, cover the sidewall that forms by dry etching perpendicular to the monocrystalline silicon layer of substrate surface; Etch away the expose portion of insulation course, expose the top surface of monocrystalline substrate; Surface portion to the monocrystalline substrate that exposes carries out isotropic etching, and the surf zone below it is positioned at movable part is etched away; Remove mask and sidewall diaphragm.

According to microminiature moving device of the present invention, because equally with prior art can use the SOI substrate, and formed the depressed area, so can eliminate owing in monocrystalline substrate be arranged in the failure problems of the movable part that the foreign matter introduced in the gap between the movable part above the gap causes, also can eliminate the monocrystalline substrate that causes owing to the foreign matter of introducing in the gap and be fixed in short circuit problem between the fixed part on the substrate.

Therefore, according to microminiature moving device superior performance of the present invention and reliability height.

Utilize method for making of the present invention, for example use commercial available SOI substrate, can produce microminiature moving device with high reliability.

Description of drawings

Fig. 1 shows the planimetric map as traditional photoswitch of microminiature moving device example;

Fig. 2 schematically shows the series of steps of making traditional photoswitch shown in Figure 1;

Fig. 3 is the top plan view according to the photoswitch of first embodiment of the invention;

Fig. 4 A is the sectional view of obtaining along A-A line among Fig. 3;

Fig. 4 B is the sectional view of obtaining along B-B line among Fig. 3;

Fig. 4 C is the sectional view of obtaining along C-C line among Fig. 3;

Fig. 5 inserts the planimetric map that has disposed the photoswitch of optical fiber in the raceway groove at optical fiber;

The planimetric map of Fig. 6 photoswitch shown in Figure 5 when to be minute surface pull out from optical fiber inserts the zone of intersection of raceway groove;

Fig. 7 shows the series of steps of the photoswitch of construction drawing 3 embodiment;

Fig. 8 is the top plan view according to the photoswitch of second embodiment of the invention;

Fig. 9 A is that the optical fiber of the photoswitch among details displayed map 8 embodiment inserts the amplification view of the zone of intersection of raceway groove;

Fig. 9 B is the amplification view of the electrostatically actuated mechanism of the photoswitch among details displayed map 8 embodiment;

Figure 10 A is the sectional view of obtaining along A-A line among Fig. 8;

Figure 10 B is the sectional view of obtaining along B-B line among Fig. 8;

Figure 10 C is the sectional view of obtaining along C-C line among Fig. 8;

Figure 11 A shows the series of steps of the method example of making photoswitch shown in Figure 8 along the cross section of A-A line among Fig. 8;

Figure 11 B shows the series of steps of optical switch preparation method along the cross section of B-B line among Fig. 8;

Figure 11 C shows the series of steps of optical switch preparation method along the cross section of C-C line among Fig. 8;

Figure 12 A is the planimetric map that amplifies, and it shows the example that the mask pattern of leading a part (placement guide) that is provided in the raceway groove is provided at the optical fiber of Figure 11 C;

Figure 12 B is the planimetric map that amplifies, and it shows another example that the mask pattern of leading a part that is provided in the raceway groove is provided at the optical fiber of Figure 11 C;

Figure 13 A is not forming under the situation of depression on the end face that shows on the cross section in monocrystalline substrate, and condensing is (example of prior art) how to take place;

Figure 13 B shows to condense under the situation that is formed with depression on the monocrystalline substrate along the cross section of A-A line among Fig. 8 and how to take place;

Figure 14 A shows the series of steps of another example of making the photoswitch method along the cross section of A-A line among Fig. 8;

Figure 14 B shows the series of steps of optical switch preparation method along the cross section of B-B line among Fig. 8;

Figure 14 C shows the series of steps of optical switch preparation method along the cross section of C-C line among Fig. 8;

Figure 15 A shows the modification of the making step of Figure 11 A and 14A on the cross section;

Figure 15 B shows the modification of the making step of Figure 11 B and 14B on the cross section;

Figure 15 C shows the modification of the making step of Figure 11 C and 14C on the cross section;

Figure 16 is the top plan view according to the photoswitch of third embodiment of the invention;

Figure 17 A has schematically provided and has made the series of steps S1 of photoswitch among Figure 16 to S4;

Figure 17 B has schematically provided when making photoswitch among Figure 16 subsequently step S5 to S8;

Figure 18 is the top plan view according to the photoswitch of fourth embodiment of the invention;

Figure 19 is the sectional view that has schematically shown one of the step of making photoswitch shown in Figure 180;

Figure 20 is the sectional view that has schematically shown the photoswitch shown in Figure 180 that optical fiber has been installed on it;

Figure 21 A has schematically provided and has made the series of steps S1 of another method of photoswitch among Figure 18 to S4; And

Figure 21 B has schematically provided and has made the step S5 subsequently of photoswitch among Figure 18 to S8.

Embodiment

With reference to the accompanying drawings, will the present invention who be applied to photoswitch be described hereinafter.

Embodiment 1

Fig. 3 is to use the top plan view of the photoswitch of SOI substrate making.Four optical fiber that form right-angled intersection on the end face 41a of smooth SOI substrate 41 receive raceway groove 42a to 42d.Receive one of four substrate surface area that raceway groove 42a are split to form to 42d by four optical fiber, be used as actuating mechanism and form and distinguish 40.Be formed with a groove (slot) 44 in actuating mechanism formation district 40, it communicates to the zone of intersection 43 of 42d with four optical fiber reception raceway groove 42a, and actuating mechanism formation district 40 is divided into two parts; In addition, form at actuating mechanism and to form a groove (recess) 45 in the district 40, it communicates with groove 44 on the relative end in groove 44 and the zone of intersection 43.The part that actuating mechanism except that groove 44 and groove 45 forms district 40 is used as fixed part 40a.

A slidably motion bar 46 is arranged in groove 44, and it carries a minute surface 47 in the inner near the zone of intersection 43.Motion bar 46 parts extend in the groove 45, wherein springs support

member

48a and 48b be respectively with the both sides of the center section of one client link motion bar 46, and springs

support member

48c and 48d are respectively with the outer end portion of one client link motion bar 46 similarly.Thereby motion bar 46 is connected to fixed part 40a by springs support member 48a to 48d, make motion bar 46 can along its vertically and the end face 41a that is parallel to SOI substrate 41 move freely.

Between springs support

member

48a and 48b and 48c and 48d, dispose a pectination electrostatically actuated mechanism, it comprises the movable comb electrode 49 that is fixed on motion bar 46 both sides.Activity comb electrode 49 is directly along the both sides of landscape configuration at

sway brace

49a and 49b, and sway

brace

49a and 49b are fixed on the motion bar 46 with the one end respectively.

Dispose first and second

fixed comb electrodes

51 and 52 in the both sides of

sway brace

49a and 49b, they and the 49 adjacent and interlaced arrangements of movable comb electrode.First and second

fixed comb electrodes

51 and 52 are separately fixed on fixed

part

51a, 51b and 52a, the 52b.The Outboard Sections of motion bar 46,

sway brace

49a and 49b, movable comb electrode 49, springs support member 48a to 48d, first and second

fixed comb electrodes

51 and 52 and fixed

part

51a, 51b, 52a and 52b all be arranged in groove 45.

Fixed part

51a, 51b, 52a and 52b are fixed on the bottom of groove 45 by being clipped in insulation course 62 in the middle of their, and be as mentioned below.

Fig. 4 A is respectively the sectional view of obtaining along A-A line, B-B line and C-C line among Fig. 3 to 4C.Substrate 41 has three-decker, and wherein the insulation course 62 that is formed by silica membrane is clipped between monocrystalline substrate 61 and the monocrystalline silicon layer 63.Utilize monocrystalline silicon layer 63, formation can be parallel to the movable part that wafer surface moves on monocrystalline substrate 61, and for example motion bar 46, minute surface 47, springs support member 48a are to 48d,

sway brace

49a, 49b and movable comb electrode 49.

In addition, similarly, utilize monocrystalline silicon layer 63 to form the fixed part 51a of first and second

fixed comb electrodes

51 and 52 and 51b and 52a and 52b, fixed part 40a and optical fiber reception raceway groove 42a fixed part to 42d.These fixed parts all are fixed on the monocrystalline substrate 61 by the insulation course 62 that is clipped in the middle.In illustrated example, insulation course 62 also be positioned at movable part below.

On the end face of monocrystalline substrate 61, between adjacent fixed part, form depression (depression) 64, promptly in having the surf zone of fixed part, do not form, as Fig. 4 A to shown in the 4C.Movable part is positioned at the top of such depression 64, and they are caved in 64 from monocrystalline substrate 61 separately like this.The depression 64 that forms on the wafer surface in the gamut that movable part moves provides enough gaps 50 between they and monocrystalline substrate 61.

Fig. 5 has shown that in the photoswitch of Fig. 3 optical fiber 71a is placed on four optical fiber respectively to 71d and receives the original state of raceway groove 42a in 42d the time.In illustrated original state (first stable state), minute surface 47 remains on optical fiber and receives the zone of intersection 43 of raceway groove 42a to 42d; For instance, the light that sends from optical fiber 71a reflects into into optical fiber 71d through minute surface 47, and similarly, the light that sends from optical fiber 71b reflects into into optical fiber 71c through minute surface 47.

On first fixed comb electrode 51, apply voltage, simultaneously with fixed part 40a and second fixed comb electrode, 52 ground connection, second fixed comb electrode 52 is by

sway brace

49a and 49b, motion bar 46 and springs support member 48a are electrically connected to movable comb electrode 49 to 48d, between first fixed comb electrode 51 and movable comb electrode 49, produce electrostatic attraction, when attractive force greater than making springs support member 48a when 48d remains on the required power of first stable state, they will be inverted to second stable state shown in Figure 6, even and still can control oneself after added voltage interruption.At this moment, minute surface 47 is pulled out from the zone of intersection 43, and in this case, the light wave that sends from

optical fiber

71a and 71b is along rectilinear propagation and intactly be injected into optical fiber 71c and the 71d respectively.

Described first and second stable states can keep its Outboard Sections to be parallel to each other and realize simultaneously by making springs support member 48a to the slight deflection of the center section of 48d length direction.By on second fixed comb electrode 52, applying voltage, simultaneously with fixed part 40a and first fixed comb electrode, 51 ground connection, between second fixed comb electrode 52 and movable comb electrode 49, produce electrostatic attraction, when attractive force greater than making springs support member 48a when 48d remains on the required power of second stable state, they will turn back to first stable state shown in Figure 5.

For instance, first or second

fixed comb electrode

51 or 52 and movable comb electrode 49 between apply voltage and can realize by following method, promptly between

fixed part

51a, 51b and 52a, 52b and first or second

fixed comb electrode

51 or 52, be connected bonding wire (bonding wire) respectively, and between bonding wire and fixed part 40a, apply voltage.

Photoswitch for described structure, can be parallel to the movable part (motion bar 46, minute surface 47, springs support member 48a are to 48d,

sway brace

49a and 49b and movable comb electrode 49) that the end face direction of monocrystalline substrate 61 moves, separate with monocrystalline substrate 61 fully by the depression 64 that forms in the monocrystalline substrate 61.Compare with the gap that about 3 μ m are thick in the prior art, the formation of depression 64 provides the gap 50 of broad---and this has eliminated the problem that foreign matter enters gap 50 and hinders the movable part motion.

Next, a kind of description of making the method for microminiature moving device will be provided, this device is included in movable part and fixed part and the parts that the be parallel to substrate surface that forms on the monocrystalline substrate moves, and wherein movable part is located at the top of the depression that the substrate surface area between adjacent stationary components and the parts forms.Fig. 7 has schematically provided the series of steps S1 of making microminiature moving device to S5, and is as described below.

Step S1: at first prepare three layers of SOI substrate 60, wherein comprise one and be clipped in insulation course 62 between monocrystalline substrate 61 and the monocrystalline silicon layer 63 by what silica membrane constituted.The coating resist forms fixed part and the mask 65 of parts and the mask 66 of movable part to form mask layer thereby form pattern by photoetching technique on the whole surf zone of monocrystalline silicon layer 63, and they are fixedly placed on the monocrystalline substrate 61 the most at last.

Shown in the top plan view of photoswitch among Fig. 3, each movable part, be motion bar 46, minute surface 47, springs support member 48a to 48d,

sway brace

49a, 49b and movable comb electrode 49, be narrower or thin at least on a direction of substrate surface; Therefore, the mask 66 of movable part is generally all narrower.By comparison, mask 65 broads of fixed part.

Step S2: utilize degree of depth gas reaction dry etching and etch away monocrystalline silicon layer 63 selectively, up to following insulation course 62 by mask 65 and 66.This etching is used a kind of ICP (inductively coupled plasma)-RIE (reactive ion etching) equipment.For the verticality of the sidewall that strengthens monocrystalline silicon layer 63, preferably adopt the vertical lithographic technique that alternately repeats conventional etching and polymer deposition (precipitation).This can be by introducing sulfur hexafluoride (SF in etching process in the plasma chamber of ICP equipment ₆) and the mixed gas of argon (Ar), in the polymer deposition process, introduce octafluorocyclobutane (C ₄F ₈) and the mixed gas of argon (Ar) realize.

When monocrystalline silicon layer 63 is carried out etching, by alternately repeating described two steps, all be deposited on the sidewall of silicon layer 63 at each operating cycle polymeric layer, they are as complete sidewall diaphragm 67.

Step S3: etch away insulation course 62 exposed portions, expose the surf zone of following monocrystalline substrate 61.This etching can adopt the wet etching of about 50% hydrofluorite (HF) solution to finish, but in this case, is by RIE equipment and adopts fluoroform (CHF ₃) and the dry etching of the mixed gas of argon (Ar) finish.

Step S4: the surf zone to the monocrystalline substrate 61 that exposes carries out isotropic etching.In this step, isotropic dry etch is to use sulfur hexafluoride (SF ₆) and the mixed gas of argon (Ar) finish.

Because isotropic dry etch involves so-called " side etching (side etching) ", so selective etching time suitably, so that kept at the monocrystalline silicon that constitutes by monocrystalline silicon layer 63 and insulation course 62 and form the most at last below the wider portion of described fixed part, and the monocrystalline silicon below forming the thin or narrower part of described movable part is the most at last removed fully.By such isotropic etching, on the end face of monocrystalline substrate 61, formed depression 64, thereby between narrower part and monocrystalline substrate 61, obtained enough gaps 50.In this example, the depression 64 also can enter into a little wider portion below, but wider portion still tightly is fixed on the monocrystalline substrate 61 by remaining monocrystalline silicon.For instance, the degree of depth of formed depression 64 is about 10 μ m.

Step S5: remove

mask

65,66 and sidewall diaphragm 67.So just obtained a kind of structure, wherein fixed part 82 is fixed on the monocrystalline substrate 61 by insulation course 62, and movable part 81 separates from monocrystalline substrate 61 owing to depression 64 with thereupon the gap 50 that produces.Groove 83 correspondences optical fiber and are received raceway groove 42a (42b is to 42d).

Etching mask

65 and 66 and can pass through O by the sidewall diaphragm 67 that polymer deposition forms ₂Dry plasma etch or use sulfuric acid (H ₂8O ₄) removed simultaneously.

When need on the sidewall of movable part 81 or fixed part, forming required film, when the same, when finishing, the manufacture craft process forms this film just as the situation that on arbitrary of the minute surface 47 of photoswitch shown in Figure 3, forms reflectance coating.

In aforesaid method for making, SOI substrate 60 is commercial available as in the prior art.Yet in this case, remove the intermediate insulating layer 62 of three layers of substrat structure does not resemble in the prior art forming movable part, but be used to stop or limit the etching of the monocrystalline silicon layer 63 above it and as electrical isolation.

In step S4, only require it is isotropic etching haply because on the end face of monocrystalline substrate 61, form the etching of depression 64, so etching is not confined to dry etching above-mentioned especially, also can be to use the wet etching of nitric acid-hydrofluorite (nitric-hydrofluoric acid) as etching agent.Yet, when the etching of monocrystalline silicon among the etching of insulation course 62 among the step S3 and the step S4 all was to use RIE equipment to adopt dry etching to finish, these two steps can be carried out continuously by the etching gas that only etching gas of step S3 is replaced with step S4---and this just allows to simplify manufacturing equipment and technology.

In addition; it is the most favourable using the polymer deposition layer to form sidewall diaphragm 67 in step S2; but; after monocrystalline silicon layer 63 is carried out anisotropic etching, sidewall diaphragm 67 also can by vaporization on the sidewall silicon dioxide or be placed in the high-temperature vapor thermal oxide sidewall and form oxide film and form.

Yet in this case; because sidewall diaphragm 67 is a silica membrane with the intermediate insulating layer 62 of SOI substrate equally; so need the exposed region of selectively only removing the insulation course 62 except that sidewall diaphragm 67 in step S3, this can finish by mode as described below.

In RIE equipment, provide a parallel-plate electrode right, the substrate 60 through step S2 etching among Fig. 7 is placed between the parallel-plate electrode, make substrate surface and pole plate keeping parallelism.Then, will contain fluoroform (CHF ₃) or the reacting gas of similar gas be passed in the plasma chamber of RIE equipment, ion in direct current (DC) the electric field accelerate plasma particle that sheath by electrode surface produces, to being carried out high-energy ion bombardment, thereby cause the ion assisted chemical reactions by the exposed surface of the insulation course 62 of etched groove trench bottom.Consequently, etching only occurs on the direction of ion incidence---and this has just guaranteed just effectively to remove the exposed region of insulation course 62, and stays sidewall diaphragm 67.

Additional disclosure uses hydrofluorite to remove the sidewall diaphragm 67 that described silicon dioxide constitutes.In this case, removed simultaneously by sidewall diaphragm 67 on the vertical sidewall of etched groove groove and the insulation course 62 below the movable part 81, but sidewall diaphragm 67 is removed very soon, therefore need not consider to such an extent as to the side etching of insulation course 62 is slight.

In the above example, movable part 81 and the marginal portion that is suspended on the fixed part 82 above the depression 64 all are made of monocrystalline silicon layer 63 and insulation course 62, shown in step S5 among Fig. 7.Especially, the lower surface of the suspended portion of fixed part 82 also is covered with insulation course 62, even under the situation in the gap below the conduction foreign matter enters into suspended portion, this also can prevent the foreign matter generation electrical short by conducting electricity between monocrystalline silicon layer 63 and the monocrystalline substrate 61.

Yet, being about under the situation that insulation course (for example 3 μ m are thick) on 10 μ m and the suspended portion bottom surface also has been removed in formed each 64 degree of depth that cave in, the total degree of depth from fixed part 82 bottom surfaces to depression 64 bottom surfaces is approximately about 13 μ m.For instance, in the environment that the size of the foreign matter that enters seldom can take place even as big as the situation that produces short circuit in so wide gap, the purpose prevent that short circuit from taking place is satisfied in the gap of broad fully, no longer need form insulation course on the bottom surface of the suspension marginal portion of fixed part.

For instance, when the movable part 81 that forms more flexible, or run into when forming the problem of stress or similar phenomenon in the interface of double-layer structure of movable part 81, can in step S5, use the insulation course 62 below the suspension marginal portion of hydrofluorite removal movable part 81 and fixed part 82.

Additional disclosure, in described example, depression 64 not only formation below movable part 81 also form between adjacent fixed part 82, that is and, depression 64 is formed on the surf zone of the monocrystalline substrate 61 that does not have fixed part 82 formation.Therefore, depression 64 also is formed on and is used for receiving optical fiber 71a and receives raceway groove 42a in 42d to the optical fiber of 71d.

Generally speaking, control the degree of depth of each depression 64 that forms by etching not too easily accurately, and when on the monocrystalline substrate 61 a plurality of groove being arranged, also form depression 64 not too easily with same depth.

Owing to above reason, the optical fiber 71a that places in such depression 64 is relatively poor inevitably to the precision of the height of 71d, so they are in height different, and this has brought because the optical axis mismatch causes the possibility that coupling efficiency descends.

Embodiment 2

Next, will provide the description of second embodiment of the invention, it is in order to eliminate problem above-mentioned, that is, it to be constructed, making each parts with high-precision height placement.

Fig. 8 is a microminiature moving device with structure like this, for example top plan view of photoswitch.Fig. 9 A and 9B are its part enlarged drawings.Figure 10 A is the sectional view of obtaining along A-A, B-B among Fig. 8 and C-C line respectively to 10C.With Fig. 3 and Fig. 4 A to the corresponding parts of the parts among the 4C still with same number-mark, it is described in detail no longer and repeats.

In the present embodiment, shown in Figure 10 C, receiving raceway groove 42a at each optical fiber provides one to lead a part 91 in the depression 64 of 42d, and optical fiber 71a is placed on respectively to 71d and leads on the part 91.Lead a part 91 and form, and the surface accuracy of leading a part 91 is height like this, make optical fiber 71a can be in sustained height with high precision to 71d by the superficial layer of the monocrystalline substrate 61 that is not etched away in 64 in depression.The minute surface 47 that is formed by monocrystalline silicon layer 63 also can High Accuracy Control to the height of 71d with respect to optical fiber 71a, and this is because minute surface 47 and optical fiber 71a can in height be controlled with reference to the end face of monocrystalline substrate 61 to 71d.

In the present embodiment, as shown in Figure 8, form

conductive path

53 and 54, they are connecting fixed part 51a, the 51b of first fixed comb electrode 51 and fixed part 52a, the 52b of second fixed comb electrode 52 respectively, and extend to the fringe region (shown in double dot dash line among Fig. 8) that actuating mechanism forms district 40.The fringe region (shown in double dot dash line among Fig. 8) that forms district 40 across the actuating mechanism of

conductive path

53 and 54 forms district 55 as electrode pad, forms the electrode pad 56 shown in Figure 10 A therein.For instance, electrode pad 56 is to be the Au/Pt/Ti film of basement membrane (base) with the Ti film, forms by sputtering method.

Figure 11 A has schematically provided to 11C and has made the step S1 of the photoswitch with described structure to S6.Figure 11 A shows making step along the cross section of the A-A among Fig. 8, B-B and C-C line respectively to 11C.To provide the description of step S1 below to S6.

Step S1: prepare SOI substrate 60.

Step S2: the coating resist forms mask layer on the end face of whole monocrystalline silicon layer 63, thereby forms the mask 65 of the fixed part of fixed configurations on monocrystalline substrate 61 and the mask 66 of movable part by the photoetching technique composition.Also form the mask 68 of leading a part simultaneously.

According to their the pattern descending sort of the size of narrow part, at first be the mask 65 of fixed part, be the mask 68 of leading a part then, be the mask 66 of movable part at last.

Leading the mask 68 of a part, can be the continuous pattern along optical fiber reception raceway groove longitudinal extension shown in Figure 12 A, also can be the discontinuous pattern shown in Figure 12 B.In the latter's situation, in following step S4, owing on the end face of the monocrystalline substrate between the adjacent island areas 61, formed groove, thus can below optical fiber, inject bonding agent by groove, thus the constant intensity of optical fiber increased.

Then, utilize degree of depth gas reaction dry etching and, etch away monocrystalline silicon layer 63 selectively, up to exposing insulation course 62 by

mask

65,66 and 68.In this example, although Figure 11 A is not shown in the 11C, also to use with foregoing Fig. 7 in the same mode of step S2, deposit film is to form the sidewall diaphragm on the sidewall that monocrystalline silicon layer 63 exposes.

Step S3: etch away the exposed region of insulation course 62, up to exposing monocrystalline substrate 61.

Step S4: adopt the isotropic etching method to etch away the surf zone of the exposure of monocrystalline substrate 61, below the thin or narrower part of the monocrystalline silicon that forms movable part the most at last, remove up to it.The result has just formed depression 64.Etching among step S3 and the S4 can be a wet etching, but uses dry etching comparatively favourable because like this can be in same etching apparatus continuously completing steps S2 to S4.

Step S5: remove

mask

65,66 and 68 and the sidewall diaphragm; etch away insulation course 62 subsequently; up to removing insulation course 62 parts that form the most at last above monocrystalline substrate 61 surf zones of leading a part 91, the result has removed the monocrystalline silicon layer 63 of leading on the part 91.

Step S6: form on district 55 and minute surface 47 zones at each electrode pad, adopt sputtering method and form the Au/Pt/Ti film by mechanical mask.Photoswitch shown in Figure 8 has so just completed.

For instance, be more than 100 μ m when wide when optical fiber receives raceway groove 42a to 42d, the width of leading a part 91 is approximately 50 μ m.In this case, suppose that depression 64 is that 10 μ m are dark, the width of then leading the mask 68 of a part 91 is 70 μ m, and this is because be used for forming the isotropic etching of depression 64, is to carry out in the horizontal and vertical directions simultaneously with same speed.

When the mask 68 of leading a part 91 forms the continuous pattern of an integral body shown in Figure 12 A, the depression 64 that optical fiber receives in the raceway groove is divided into along two parts of raceway groove longitudinal extension, and when mask 68 forms discontinuous or discrete island-shaped pattern shown in Figure 12 B, just can obtain the advantage of increased optical fiber constant intensity mentioned above; In addition, the island areas of separating can interconnect two parts depression 64---and this is convenient to be injected into optical fiber and receives ultraviolet (UV) curing adhesive below the optical fiber in the raceway groove or the smooth flow of similar substance, bonding agent can be received in the raceway groove at whole optical fiber at once reach even height.

Leading a part 91 and can promptly be caved in by fixed part and 64 surround like this, and at the edge of substrate, it may contain not the edge that is surrounded by depression 64 and fixed part, as optical fiber receives in the example of raceway groove.

Lead a part 91 and be used for supporting optical fiber in the present embodiment, it also can be used for supporting chip element such as lens, semiconductor light-emitting elements or semiconductor light modulator.Under the situation of supporting chip element, on other parts, form in the electrode pad, on the surface of leading a part 91, form metal level as electrode pad.

As previously mentioned, provide depression 64 to overcome the problem that foregoing movable part breaks down or caused electrical short by foreign matter.Now, will provide by coagulum (condensation) is the description that dewfall (dew) (also can be used as foreign matter from broadly) causes short circuit.

For comparison purposes, Figure 13 A shows to condense in the example of the prior art that does not form depression 64 and how to take place.Ref. No. 75 expression dewfall.Dewfall is easy in silicon and metal (the boundary vicinity formation between the gold (Au).When forming the film of electrode pad 56 by the mechanical mask of use, because metal level 56a and 56b are formed on the sidewall of the surface of monocrystalline substrate 61 of exposure and monocrystalline silicon layer 63, then form the dewfall 75 as shown in Figure 13 A, thereby caused short circuit between electrode pad 56-1 and the 56-2.

Figure 13 B shows the dewfall 75 that forms in depression 64, this shows that depression 64 can prevent the short circuit that is caused by coagulum.

Additional disclosure is not only photoswitch and is comprised that all this microminiature moving devices that use the SOI substrate to make all are placed in the encapsulation usually, but is difficult to obtain the encapsulating structure of sealing fully in practice; As time goes on water vapor can progress in the encapsulation, and the variation of simultaneous temperature environment can make on the device surface condenses.

Next, the another kind of method of making photoswitch shown in Figure 8 will be provided.The same to the situation of 11C with Figure 11 A, Figure 14 A has schematically provided series of steps S1 according to the method for this case making photoswitch to S6 to 14C.

Step S1: prepare SOI substrate 60.

Step S2: on the surf zone of whole monocrystalline silicon layer 63, form silicon dioxide film, with the mask 66 of the mask 65 that forms fixed part, movable part with lead the mask 68 of a part, this is the same with Figure 11 A situation of step S2 in the 11C through photoetching composition for silicon dioxide film then.The silicon dioxide film that forms mask layer is thicker than the insulation course 62 that is made of silicon dioxide equally.

Then, utilize degree of depth gas reaction dry etching to etch away monocrystalline silicon layer 63 selectively, up to exposing insulation course 62 by

mask

65,66 and 68.In this example, although not shown in the 14C, equally also on the sidewall that monocrystalline silicon layer 63 exposes, formed the sidewall diaphragm at Figure 14 A.

Step S3: etch away the exposed region of insulation course 62, up to exposing monocrystalline substrate 61.In this step,

mask

65,66 and 68 has also stood etching, but because they are thicker than insulation course 62, so can not etched away fully.

Step S4: the same with Figure 11 A situation of step S4 in the 11C, etch away the surf zone of the monocrystalline substrate 61 of exposure by the isotropic etching method.

Step S5: remove the sidewall diaphragm, subsequently with Figure 11 A same mode of step S5 in the 11C, etch away insulation course 62, the result has removed the monocrystalline silicon layer 63 of leading on the part 91.Simultaneously, also etch away

mask

65,66 and 68.

Above method for making uses silicon dioxide film rather than resist to form

mask

65,66 and 68.Use silicon dioxide film to involve a step, but silicon dioxide film is stronger than resist to the repellence of dry etching, so be highly reliable to its composition.

Reference Figure 11 A to 11C and Figure 14 A in described two kinds of method for makings of 14C; in step S2, in gas reaction dry etching process, be deposited on film (polymer deposition layer) on the sidewall that monocrystalline silicon layer 63 exposes as the sidewall diaphragm in the etching process of step S4; but in the method shown in the 14C, the sidewall diaphragm can be to carry out the silicon dioxide film that thermal oxide forms behind step S2 at Figure 14 A.

Provide following listed advantage by the film formed sidewall diaphragm of silicon dioxide.

A) silicon dioxide film as the sidewall diaphragm in the etching process of monocrystalline substrate 61, more more reliable than polymer deposition layer.

B) when needs obtain a smooth vertical surface (sidewall surfaces) as minute surface, booster action is played in the complanation meeting of vertical surface in the step that forms the dioxide film.

C) owing to do not need to form and keep desired polymer deposition layer, this can improve the dirigibility of whole technology, such as alternately repeat etching and polymer deposition step in degree of depth gas reaction dry etching.

Figure 11 A to 11C and Figure 14 A in the method for making shown in the 14C, covering the monocrystalline silicon layer 63 of leading on the part 91 can remove simultaneously along with the etching of insulation course 62 among the step S5, but the marginal portion that is positioned at the insulation course 62 under the fixed part also can be etched away, thereby between monocrystalline substrate 61 and monocrystalline silicon layer 63, form small gap, shown in the dotted line among Figure 13 B 76.

In this case, dewfall 75 accumulates in this gap sometimes, and other foreign matter also enters into this gap easily---and this makes the possibility that short circuit has been arranged between monocrystalline substrate 61 and the monocrystalline silicon layer 63." and S6 has shown the short circuit that how to prevent that the appearance owing to such minim gap from causing to step S5, S5 ', the S5 of Figure 15 A in the 15C.Below these steps will be described.

According to the step S1 of Figure 11 A in to 11C or Figure 14 A to 14C to the same mode of S5, completing steps S1 is to S5.

Step S5 ': the monocrystalline silicon layer 63 of exposure and the surf zone of monocrystalline substrate 61 form silicon dioxide film 69 through thermal oxide.

Step S5 ": the composition electrode pad forms the silicon dioxide film 69 on the monocrystalline silicon layer 63 in the district 55, the window 70 that is used for conducting electricity with formation.

Step S6: form in district 55 and the minute surface 47 formation districts at each electrode pad, form the Au/Pt/Ti film by sputtering method.

Forming silicon dioxide film 69 by thermal oxide in above step guarantees to have prevented to be short-circuited in described gap.

Be applied to first embodiment of photoswitch according to the present invention noted earlier, provide depression 64 possibility of having avoided the movable part short circuit and having broken down, constitute simultaneously and lead a part 91 permission parts with hi-Fix by the not surf zone of removal of the monocrystalline substrate 61 in the depression 64.Though described depression 64 and to lead a part 91 be that isotropic etching by monocrystalline silicon forms, they also can form by the anisotropic etching of monocrystalline silicon.

Embodiment 3

Next, will provide a kind of device structure and make the description of the method for this device, the depression of this device and to lead a part be that anisotropic etching by monocrystalline silicon forms.

Figure 16 has shown a photoswitch as microminiature moving device with described structure.With the corresponding parts of the parts of photoswitch among Fig. 3 still with same number-mark, it is described in detail no longer and repeats.

In the present embodiment, photoswitch is to use SOI substrate 60 to make, and wherein the insulation course 62 that is made of silicon dioxide film is clipped in its top end surface between monocrystalline substrate 61 and monocrystalline silicon layer 63 that (100) Jinping face forms.Four optical fiber receive raceway groove 42a to 42d along monocrystalline substrate 61＜100〉crystal orientation formation.

On the other hand, constitute the support member 48a of minute surface 47, the motion bar 46 of movable part, similar springs and 48b, sway

brace

49a and 49b and movable comb electrode 49 mainly with those be not parallel to＜100〉direction lines form, and in the present embodiment, motion bar 46 supports by the support member 48a and the 48b of a pair of similar springs.With being not parallel to＜110〉direction lines, form perforate or hole 58 in the thicker part of movable part.Yet on the outer shape of details, they may partly comprise and be parallel to＜110〉direction lines.

Electrostatically actuated mechanism in the present embodiment is made of a pair of movable comb electrode 49 and fixed comb electrode 51.Fixed comb electrode 51, hold the groove 44 of motion bar 46 and close on the groove 45 of groove 44, also be main be not parallel to＜110〉direction lines form.In the present embodiment, minute surface 47 initially remains in the zone of intersection 43, and by applying voltage at

movable comb electrode

49 and 51 of fixed comb electrodes, minute surface 47 is drawn out the zone of intersection 43 and remains on the pull-out location in the process that voltage applies.

Receive raceway groove 42a in 42d at each optical fiber, utilize the surf zone formation of not removed monocrystalline substrate 61 to lead a part 101.This routine sprocket bit part 101 along monocrystalline substrate 61＜110〉direction be patterned into the form of matrix or grid.Every optical fiber is placed on leading on the part 101 that such matrix or grid configuration are arranged.

Figure 17 A and 17B have schematically provided and have made the step S1 of the photoswitch with described structure to S8.

Step S1: prepare SOI substrate 60, wherein insulation course 62 is clipped between the monocrystalline substrate 61 and monocrystalline silicon layer 63 of its end face formation (100) face.The end face of monocrystalline silicon layer 63 forms silicon dioxide film as mask layer through oxidation, then by photoetching composition form fixed part mask 65, movable part mask 66 and lead the mask 111 of a part.

The profile of each mask 111 by be parallel to monocrystalline substrate 61＜110〉direction lines limit, and the profile of each mask 66 mainly by be not parallel to＜110〉direction lines limit.The mask 111 of leading a part forms narrowlyer than other mask.Particularly, the width of mask 111 is about 1 to 2 μ m and arranges with matrix form, but the width of mask 111 is greater than the thickness of insulation course 62.

Step S2: utilize degree of depth gas reaction dry etching and etch away monocrystalline silicon layer 63 by

mask

65,66 and 111, the insulation course 62 below exposing.Like this, just form movable part 81 and fixed part 82, and below leading a part mask 111, formed fillet structure 112.

Step S3: etch away the exposed region of insulation course 62, thereby expose the top surface of monocrystalline substrate 61.Use the aqueous solution of hydrofluorite to carry out etching and continue the short period.For example, contain in use under the situation of aqueous solution of 50wt% hydrofluorite, etching time is approximately 3 minutes.In this case, selected etching time is not too long, not the degree of long insulation course 62 below getting rid of fillet structure 112 fully.Carry out this step to remove sull minimumly by the RIE method among the described step S5 after a while, etch away simultaneously by the film formed

mask

65,66 and 111 of silicon dioxide.

Step S4: monocrystalline silicon layer 63 and monocrystalline substrate 61 are carried out thermal oxide.The amount of oxidation of selecting is greater than the value of complete oxidation fillet structure 112.Like this, on the whole exposed region of monocrystalline silicon layer 63 and monocrystalline substrate 61, formed heat oxide film 113.The heat oxide film that forms on the sidewall of movable part 81 and fixed part 82 is as the sidewall diaphragm during anisotropic etching among the following step S6.

Step S5: etch away the heat oxide film 113 that on the top surface of monocrystalline substrate 61 and monocrystalline silicon layer 63, covers, thereby expose their top surface.For example, by using CHF ₃The RIE method of-Ar mixed gas is finished this etching.Because RIE can not produce etching being parallel on the direction of incident ion basically, so can not remove the heat oxide film on movable part 81 and fixed part 82 sidewalls.

Step S6: use the KOH aqueous solution that monocrystalline silicon layer 63 and monocrystalline substrate 61 are carried out anisotropic etching.As shown in the figure, etch away the surf zone of the exposure of monocrystalline substrate 61 and monocrystalline silicon layer 63, the zone below movable part 81 is removed, and the heat oxide film 113 above them is removed in the rapid S5 of previous step.Below movable part 81, cause the side etching, thereby form depression 64 by (100), (110) and (311) face.

On the other hand, owing to be arranged in the fillet structure 112 that optical fiber receives raceway groove, have on the whole be parallel to monocrystalline substrate 61＜110〉direction latticed structure, so constituted reverse taper hole 102 by (111) face, but below fillet structure 112, owing to do not have the side etching to take place here, so the surface of monocrystalline substrate 61 is kept.Like this, depression 64 is made of one group of reverse taper hole 102 respectively, and in depression 64, formed grid shape lead a part 101.

Step S7: the heat oxide film 113 on the sidewall of the removal of use hydrofluorite movable part 81, fixed part 82 and fillet structure 112.Then, do not illustrate, form electrode pad, meanwhile, on each surface of minute surface, form metal film though give.This metal is preferably gold (Au).

Like this, by the described step photoswitch shown in Figure 16 that completed.Additional disclosure, the step S8 among Figure 17 B has shown that optical fiber 71 puts into the state that optical fiber receives raceway groove, in addition high precision is definite for the part 101 of leading that the height of optical fiber 71 forms by the remaining surf zone by monocrystalline substrate 61.Do not illustrate though give, optical fiber 71 passes through adhesive.

As mentioned above, according to present embodiment, depression 64 can form between the fixed part on the monocrystalline substrate 61 that the anisotropic etching by monocrystalline silicon forms in adjacent stationary distribution, and can be in the raceway groove of receiving optical fiber 71, lead a part 101 by what the surf zone of remaining monocrystalline substrate 61 in the depression 64 formed grid shape.

Embodiment 4

In described embodiment, optical fiber 71 is placed on leading on the part 101 of grid shape.In the present embodiment, lead a part and form two parallel ridges that receive the longitudinal extension of raceway groove along optical fiber, form a V-shaped groove therebetween in order to support optical fiber accurately.

Figure 18 has shown a photoswitch according to present embodiment.With the corresponding parts of the parts among Figure 16 by identical number-mark.

In the present embodiment, receive raceway groove 42a in 42d at each optical fiber, two parallel ridges 103 that provide the residual surface zone by monocrystalline substrate 61 to form constitute leads a part 104.Ridge 103 extends along being parallel to the direction that optical fiber receives raceway groove, promptly along monocrystalline substrate 61＜110〉direction extend.Define a V-shaped groove leading between two ridges 103 of a part 104.

Corresponding with the step S6 among Figure 17 B, Figure 19 has shown how to form V-shaped groove.In this example, by with Figure 17 A and 17B in step S1 to the same step of S5, two fillet structures 112 that extend in parallel of formation in optical fiber reception raceway groove ', and adopt the anisotropic etching method of monocrystalline silicon, fillet structure 112 ' between the top surface of monocrystalline substrate 61 in (111) plane, form a V-shaped groove 105.Two fillet structures 112 ' the outside goodly become V-shaped groove 106.

Figure 20 has shown that optical fiber 71 is placed on the state in the V-shaped groove that constitutes between two parallel ridges 103 leading a part 104; V-shaped groove 105 has guaranteed the hi-Fix of optical fiber 71.In addition, V-shaped groove 105 can accurately be located optical fiber on vertical direction and horizontal direction, and design alternative by V-shaped groove 105, promptly by suitably selecting to adjust the height of the optical axis of optical fiber 71 easily by the interval between regional two ridges 103 that form of the residual surface of monocrystalline substrate 61.

Form the method that forms of leading a part 104 and between them, forming V-shaped groove 105 by two ridges 103, be not confined to described method shown in Figure 19 especially.Also can adopt another kind of method, what wherein form leads the pattern width of a pattern width of part mask greater than the movable part mask, only thermal oxide is carried out on the surface of fillet structure then limitedly, rather than whole oxidation, thereby top fillet structure is removed in the insulation course zone that then etches away below the fillet structure.Figure 21 A and 21B show the series of steps S1 of this method for making to S8, and they are corresponding to S8 with the step S1 among Figure 17 A and the 17B.

In this example, shown in step S1 among Figure 21 A, formation lead the pattern width of a pattern width of part mask 111 greater than movable part mask 66, and in step S4 the thermal oxide by monocrystalline silicon to fillet structure 112 ' the surface carry out thermal oxide.By with Figure 17 A and 17B in step S1 to the same mode completing steps S1 of S6 to S6, thereby two fillet structures 112 ' between form V-shaped groove 105.When V-shaped groove 105 forms desired size, in step S6, finish the anisotropic etching of monocrystalline silicon.

In step S7, etch away insulation course 62, remain in the insulation course 62 that constitutes above two ridges 103 of leading a part 104, meanwhile also etch away heat oxide film 113 up to getting rid of.Get rid of insulation course 62 by anisotropic etching in this way, so also just removed fillet structure 112 '.Insulation courses 62 in this example below the movable part 81 also have been etched away, and these are different with situation among Figure 19.

Method for making as the photoswitch of microminiature moving device has more than been described, wherein the anisotropic etching by monocrystalline substrate 61 forms depression 64, and in depression 64, utilize the residual surface zone formation of monocrystalline substrate 61 to lead a

part

101 or 104 simultaneously, be used for placing component; Compare with the isotropic etching of leading a part 91 with foregoing formation depression 64, consider that structural stability and precision preferably use anisotropic etching.

Claims

1. microminiature moving device, it is included in the movable part that move on described monocrystalline substrate surface that is parallel to that is provided with on the monocrystalline substrate, and fixed part, wherein:

Described fixed part is fixed on the described monocrystalline substrate by the insulation course that is clipped in the middle; And

Form depression in the surf zone of the described monocrystalline substrate that does not form described fixed part, described movable part is configured in the top of described depression.

2. device as claimed in claim 1, wherein:

Be used for providing in the described depression of placing component the part of leading that the residual surface zone that utilizes described monocrystalline substrate forms.

3. device as claimed in claim 2, wherein:

A described part of leading is a grid shape.

4. device as claimed in claim 2, wherein:

Each described part of leading is formed by two parallel ridges, and this parallel ridges is separated by the V-shaped groove between them.

5. device as claimed in claim 3, wherein:

The end face of described monocrystalline substrate is (100) face, and along described monocrystalline substrate＜110〉direction form described lattice-shaped element of leading a part.

6. device as claimed in claim 1, wherein:

The end face of described monocrystalline substrate is (100) face, and along described monocrystalline substrate＜110〉direction form described ridge of leading a part.

7. method of making microminiature moving device as claimed in claim 1, the step that described method comprises has:

Form mask layer on the entire top surface of the monocrystalline silicon layer of three layers of SOI substrate, wherein the SOI substrate has the insulation course that is clipped between described monocrystalline substrate and the described monocrystalline silicon layer;

The described mask layer of composition forms the mask of described fixed part and by the mask of the described movable part that constitutes of narrower pattern;

Adopt the gas reaction dry etching and etch away described monocrystalline silicon layer selectively, up to exposing described insulation course by described mask;

Use the sidewall diaphragm to cover the sidewall that forms by described dry etching perpendicular to the described monocrystalline silicon layer of described substrate surface;

Etch away the expose portion of described insulation course, to expose the top surface of described monocrystalline substrate;

The surface portion that described monocrystalline substrate is exposed carries out isotropic etching, and the surf zone below it is positioned at described movable part is etched away; And

Remove described mask and described sidewall diaphragm.

8. method of making described microminiature moving device as claimed in claim 2, the step that described method comprises has:

Form mask layer on the entire top surface of the monocrystalline silicon layer of three layers of SOI substrate, wherein the SOI substrate has an insulation course that is clipped between described monocrystalline substrate and the described monocrystalline silicon layer;

The described mask layer of composition forms the mask of described fixed part, the described mask of a part and the mask of described movable part of leading, and the mask of described fixed part is the wideest, and described mask second of leading a part is wide, and the mask of described movable part is the narrowest;

Remove described mask and described sidewall diaphragm, and etch away described insulation course, be removed up to being in a described described insulation course of leading above the part.

9. as claim 7 or 8 described methods, wherein:

Described insulation course and described mask layer form by silicon dioxide film, and the film thickness of described mask layer is greater than the film thickness of described insulation course.

10. the method for a making such as claim 3 or 4 described microminiature moving devices, the step that described method comprises has:

Form mask layer on the entire top surface of the monocrystalline silicon layer of three layers of SOI substrate, wherein the SOI substrate has one and is clipped in its end face and is described monocrystalline substrate of (100) face and the insulation course between the described monocrystalline silicon layer;

The described mask layer of composition, form its profile by be parallel to described monocrystalline substrate＜described mask of leading a part that 110〉direction lines limit, its profile is described by being not parallel to＜mask of the described movable part that 110〉direction lines limit, and the mask of described fixed part, described mask of leading a part is narrower than other mask;

Remove the expose portion and the described mask of described insulation course;

Described monocrystalline silicon layer of thermal oxide and described monocrystalline substrate, up in the described fillet structure that forms below the mask of a part led fully by thermal oxide;

Etch away the heat oxide film on the top surface of described monocrystalline substrate, to expose described substrate;

The surface portion that described monocrystalline substrate is exposed carries out anisotropic etching, and the surf zone below it is positioned at described movable part is etched away; And

Etch away the part of described thermal oxide.

11. a method of making microminiature moving device as claimed in claim 6, the step that described method comprises has:

The described mask layer of composition, form its profile by be parallel to described monocrystalline substrate＜described mask of leading a part that 110〉direction lines limit, its profile is described by being not parallel to＜mask of the described movable part that 110〉direction lines limit, and the mask of described fixed part, the mask of described fixed part is the wideest, described mask second of leading a part is wide, and the mask of described movable part is the narrowest;

Described monocrystalline silicon layer of thermal oxide and described monocrystalline substrate form heat oxide film on the surf zone of the whole exposure of described monocrystalline silicon layer and described monocrystalline substrate;

Etch away the heat oxide film on the top surface of described monocrystalline substrate, expose the top surface of described substrate;

The surface portion that described monocrystalline substrate is exposed carries out anisotropic etching, and the surf zone below it is positioned at described movable part is etched away and described V-shaped groove becomes desired structure; And

Etch away described insulation course, the insulation course above being positioned at the surf zone that forms the described described monocrystalline substrate of leading a part is removed.