CN102236163B - Micro-electro mechanical system (MEMS) light valve based display device and forming method thereof - Google Patents

Abstract

The invention provides a micro-electro mechanical system (MEMS) light valve based display device. The device comprises a substrate, an MEMS switch and an MEMS light valve positioned on the surface of the substrate, wherein the MEMS light valve at least comprises a fixed optical grating and a movable optical grating which is arranged relative to the fixed optical grating; the MEMS switch is electrically connected with the MEMS light valve; and the relative positions of the movable grating and the fixed grating in the MEMS light valve can be controlled by applying an electric signal to the MEMS light valve through the MEMS switch. The invention also provides a method for forming the MEMS light valve based display device. The MEMS switch with a simple structure is adopted to replace a traditional thin film transistor (TFT) switch, and the electric signal is applied to the MEMS light valve through the MEMS switch, so that the relative positions of the movable optical grating and the fixed optical grating in the MEMS light valve can be controlled; and the MEMS switch has a simple structure, so that the manufacture process for the display device is greatly simplified, and the manufacture cost is reduced.

Description

Based on display device of MEMS light valve and forming method thereof

Technical field

The present invention relates to field of semiconductor manufacture, particularly a kind of display device based on the MEMS light valve and forming method thereof.

Background technology

Liquid crystal flat panel display; Special TFT-LCD is at present at the display device of catching up with and surpass CRT aspect the combination properties such as brightness, contrast, power consumption, life-span, volume and weight comprehensively, and its function admirable, large-scale production characteristic are good; Automaticity is high; The cost of raw material is cheap, and development space is wide, might be the main product of display of future generation.

Liquid crystal indicator mainly comprises: substrate is provided with backlight in this substrate; Pixel electrode is positioned in the said substrate, also has TFT (thin film transistor switch) array in the substrate, and this TFT (thin film transistor switch) array is used for being electrically connected with pixel electrode, the current potential of control pixel electrode; The color filter corresponding, and the liquid crystal layer between pixel electrode and color filter with pixel electrode, and on the one side of liquid crystal layer, be formed with common electrode layer at color filter.To pixel electrode electromotive force is provided through TFT (thin film transistor switch) array; Make between common electrode layer and the pixel electrode and have electric potential difference; Through the liquid crystal deflection in this electromotive force official post liquid crystal layer; According to the angle of electromotive force extent control liquid crystal deflection, thereby can control what of light that light transmission liquid crystal layer that backlight sends is sent to color filter.In the liquid crystal indicator, the backlight that uses is white light, at first only becomes polarized light and just can pass through liquid crystal layer; Polarization makes the utilization factor of light only have 50%; When light again through color filter, the utilization factor of light has only 33% at most, so the utilization factor of light is lower in the liquid crystal indicator.In addition, above-mentioned liquid crystal indicator also has otherwise defective: for example angular field of view is little, and complex structure, cost are high.

Along with the development of MEMS (microelectromechanical systems) technology, in display device, utilize MEMS light valve replacement liquid crystal layer, thereby the transmittance of the light that the control backlight sends is realized the demonstration of liquid crystal.The Chinese patent that on March 26th, 2008, disclosed publication number was CN101151206A discloses a kind of display device with the MEMS light valve; This patent adopts the MEMS light valve replacement liquid crystal of high-speed and high-efficiency; No longer need polaroid, color filter and ITO electrode, can increase substantially optical efficiency, reduce power consumption and manufacturing cost.

But the MEMS light valve in the existing display device all is by the dull and stereotyped micro-processing technology of existing TFT-LCD, controls shows signal in conjunction with TFT and MEMS light valve, and therefore, this technology is still complicated, and manufacturing cost is still higher.

Summary of the invention

The problem that the present invention solves provides a kind of display device based on the MEMS light valve and forming method thereof, solves the display device complex process of existing TFT-MEMS light valve, the manufacturing cost problem of higher.

For addressing the above problem, the present invention provides a kind of display device based on the MEMS light valve, comprising:

Substrate;

Be positioned at the mems switch and the MEMS light valve of said substrate surface, the removable slit that said MEMS light valve includes fixed grating at least and is provided with respect to fixed grating;

Said mems switch is electrically connected on the MEMS light valve, applies electric signal to the MEMS light valve through mems switch, with the relative position of removable slit and fixed grating in the control MEMS light valve.

Optional, said mems switch comprises: first electrode and third electrode; With respect to second electrode of first electrode and third electrode setting, said second electrode comprises supporting section and the conductive layer that is connected with supporting section, and wherein, third electrode has contact projection with respect to the surface of conductive layer; When first electrode and second electrode had potential difference (PD), said conductive layer was drawn close to third electrode under the effect of electrostatic force, makes the contact projection of said conductive layer and third electrode electrically contact, with through mems switch control MEMS light valve.

Optional, said first electrode lays respectively at the one or both sides of third electrode.

Optional, be positioned at said first electrode and the second interelectrode cavity.

Optional, said second electrode or third electrode and MEMS light valve are electrically connected.

Optional, when the potential difference (PD) scope of first electrode and second electrode was 2～50V, the contact projection of said conductive layer and third electrode electrically contacted.

Optional, the material of said first electrode, second electrode and third electrode is conducting metal or conductive non-metals.

Optional, said MEMS light valve also comprises:

The drive electrode that is provided with respect to removable slit, and the grating electrode that is connected with said removable slit, when said drive electrode and grating electrode had potential difference (PD), moved with respect to fixed grating towards the drive electrode direction on said removable slit edge.

Optional, said drive electrode is positioned at the one or both sides of removable slit.

Optional, also comprise the storage unit that is electrically connected with said MEMS light valve and mems switch.

Optional, said storage unit is a MM CAP, and said MM CAP has two pole plates, and one of them pole plate is connected between MEMS light valve and the mems switch, another pole plate ground connection.

The present invention also provides a kind of formation method of the display device based on the MEMS light valve, may further comprise the steps:

Substrate is provided;

In said substrate, form mems switch and MEMS light valve, the removable slit that said MEMS light valve includes fixed grating at least and is provided with respect to fixed grating;

Wherein, said mems switch is electrically connected on the MEMS light valve, applies electric signal to the MEMS light valve through mems switch, with the relative position of removable slit and fixed grating in the control MEMS light valve.

Optional, the formation method of said mems switch comprises:

In substrate, form first electrode, third electrode and supporting section, wherein, said third electrode has contact projection;

Deposit first dielectric layer, said first dielectric layer is filled the gap between first electrode, third electrode and supporting section, and exposes the surface of first electrode, third electrode and supporting section at least;

Deposition of sacrificial layer, said sacrifice layer cover said first electrode and third electrode, and the sacrificial layer surface of corresponding third electrode has convexity;

On said sacrifice layer, form conductive layer, said conductive layer is electrically connected with supporting section, and said conductive layer and supporting section constitute second electrode;

Remove sacrifice layer, between said first electrode, second electrode and third electrode, form cavity.

Optional, said first electrode is positioned at the one or both sides of said third electrode.

Optional, comprise, be electrically connected said second electrode and MEMS light valve or be electrically connected said third electrode and MEMS light valve.

Optional, when the potential difference (PD) scope of first electrode and second electrode was 2～50V, said contact projection contacted with third electrode.

Optional, the material of said first electrode, second electrode and third electrode is conducting metal or conductive non-metals.

Optional, said removable slit is positioned at a side of fixed grating, and the opposite side that said formation method also is included in said fixed grating forms backlight.

Optional, form said mems switch and MEMS light valve simultaneously, comprising:

Substrate is provided, in said substrate, forms fixed grating;

On said fixed grating, form interlayer dielectric layer;

On interlayer dielectric layer, form the drive electrode of first electrode, third electrode, supporting section and the MEMS light valve of mems switch, said third electrode has contact projection;

Deposit first dielectric layer, said first dielectric layer is filled the gap between first electrode, third electrode, supporting section and drive electrode, and exposes the surface of said first electrode, third electrode, supporting section and drive electrode at least;

At the said first dielectric layer surface deposition sacrifice layer, said sacrifice layer exposes supporting section and drive electrode;

The conductive layer and the removable slit of MEMS light valve, said conductive layer and the supporting section that on said sacrifice layer, form mems switch constitute second electrode;

Remove sacrifice layer, between said first electrode, second electrode and third electrode, form first cavity, said removable slit is with respect to the fixed grating setting, and is formed with second cavity with interlayer dielectric layer.

Optional, said first electrode is positioned at the one or both sides of said third electrode.

Optional, also comprise being electrically connected said second electrode and MEMS light valve or being electrically connected said third electrode and the MEMS light valve.

Optional, also comprising the formation grating electrode, said grating electrode is electrically connected with the removable slit of said MEMS light valve.

Compared with prior art, the present invention has the following advantages:

Through adopting mems switch simple in structure to substitute traditional T FT switch; Apply electric signal to the MEMS light valve through mems switch; Relative position with removable slit and fixed grating in the control MEMS light valve; Said mems switch is simple in structure, has simplified the manufacturing process of said display device greatly, reduces manufacturing cost.

Mems switch comprises first electrode and third electrode, reaches second electrode that is oppositely arranged with third electrode, whether contact with third electrode through second electrode, and control MEMS light valve, thus realize control to the display device shows signal.Said mems switch is simple in structure, has simplified the manufacturing process of said display device greatly, reduces manufacturing cost.

Further, form mems switch when forming the MEMS light valve, utilize the opening and closing of said mems switch control MEMS light valve, thereby realize the control of display device shows signal, simplified the manufacturing process of said display device, reduce manufacturing cost.

Description of drawings

Fig. 1 is the electrical block diagram based on MEMS light valve display device of an embodiment.

Fig. 2 be an embodiment based on MEMS light valve structure synoptic diagram in the display device of MEMS light valve.

Fig. 3 be another embodiment based on MEMS light valve structure synoptic diagram in the display device of MEMS light valve.

Fig. 4 be again an embodiment based on MEMS light valve structure synoptic diagram in the display device of MEMS light valve.

Fig. 5 be an embodiment based on mems switch structural representation in the display device of MEMS light valve.

Fig. 6 is the schematic top plan view based on MEMS light valve in the display device of MEMS light valve of an embodiment.

Fig. 7 is the formation method flow synoptic diagram based on mems switch in the display device of MEMS light valve of an embodiment.

Fig. 8 is the formation method flow synoptic diagram based on the display device of MEMS light valve of an embodiment.

Fig. 9 to Figure 21 is the formation method structural representation based on the display device of MEMS light valve of one embodiment of the invention.

Embodiment

For make above-mentioned purpose of the present invention, feature and advantage can be more obviously understandable, does detailed explanation below in conjunction with the accompanying drawing specific embodiments of the invention.

Specify the display device of the specific embodiment of the invention below in conjunction with specific embodiment.

Fig. 1 is the electrical block diagram based on MEMS light valve display device.As shown in Figure 1; Display device comprises in the present embodiment: substrate; Be positioned at suprabasilmulti-strip scanning line 11,12 ..., 1m, be positioned at suprabasilmany data lines 21,22 ..., 2n, be positioned at suprabasil a plurality of mems switch 30,electric capacity 40 and MEMSlight valve 50; The multi-strip scanning line is parallel to each other, and many data lines are parallel to each other, and data line is vertical each other with sweep trace.Wherein, Said mems switch 30 has first electrode, second electrode and third electrode; Said sweep trace is connected with first electrode electricity of mems switch 30, and said data line is connected with second electrode electricity of mems switch 30, and the third electrode of MEMSlight valve 50 and mems switch 30 is electrically connected.

Through on first electrode of mems switch 30 and second electrode, applying a potential difference (PD), make second electrode and the third electrode conducting of mems switch 30, be electrically connected because of third electrode and MEMSlight valve 50 again, and then control imposes on the voltage of MEMSlight valve 50; Wherein,electric capacity 40 is connected between the third electrode and ground of mems switch.

In another embodiment, the connected mode of the third electrode and second electrode can be exchanged, and promptly said data line is electrically connected with the third electrode of mems switch 30, and second electrode electricity of MEMSlight valve 50 and mems switch 30 is connected.Electric capacity 40 is connected between second electrode and ground of mems switch.

Shown in Figure 2 is based on MEMS light valve structure synoptic diagram in the display device of MEMS light valve in the present embodiment.As shown in Figure 2, comprising: substrate 001, be positioned at the fixed grating 002 in the said substrate 001, said fixed grating 002 is fixed in substrate 001 surface; The removable slit 003 that is oppositely arranged with said fixed grating 002; Said MEMS light valve also comprises grating electrode 006, and said grating electrode 006 1 ends are electrically connected on removable slit 003; The drive electrode 005 that is oppositely arranged with said grating electrode 006.

When said grating electrode 006 had potential difference (PD) with drive electrode 005, grating electrode 006, drive electrode 005 had the xenogenesis electric charge, make to produce electrostatic force between grating electrode 006 and the drive electrode 005.Under the effect of electrostatic force; Drive electrode 005 attract grating electrode 006 towards drive electrode 005 direction near; And then drive and the removable slit 003 that said grating electrode 006 is electrically connected, make said removable slit 003 and the fixed grating 002 that is positioned at its below be formed with relative displacement.And then make the light that appears from fixed grating 002 can see through said removable slit 003 selectively.The material of said drive electrode 005, removable slit 003 and grating electrode 006 is conducting metal or conductive non-metals.

Wherein, Said removable slit 003 is positioned at a side of fixed grating 002; The opposite side of said fixed grating 002 also is formed with backlight (not shown), and said backlight provides light to see through said fixed grating 002, and appears through the gap of removable slit 003; If blocked by said removable slit 003 lightproof part, then this part light can not appear.

In the present embodiment, the both sides of said drive electrode all are formed with grating electrode, as other embodiment, can also be only be formed with grating electrode in a side of said drive electrode.

In the present embodiment, said drive electrode 005 only is positioned at a side of removable slit 003, and being positioned at removable slit 003 opposite side is fixed pivot 007, is used for fixing removable slit 003.And the syndeton between said fixed pivot 007 and the said removable slit 003 is the loop configuration shown in Fig. 2; Promptly said removable slit 003 is not carried out straight the connection with fixed pivot 007, but said fixed pivot 007 is connected with removable slit 003 through the loop configuration 008 of both sides.Said loop configuration 008 has elasticity, makes 007 of removable slit 003 and fixed pivot have certain telescopic space, makes that said removable slit 003 can be under the effect of electrostatic force, moves towards the direction of drive electrode 005.

As other embodiment, said drive electrode 005 can also be positioned at the both sides of said removable slit 003 simultaneously, so that said removable slit 003 can move to the drive electrode direction of both sides.

Fig. 3 is the floor map of the MEMS light valve of another specific embodiment, and with reference to figure 3, the fixed grating of this specific embodiment is circular (not shown), has a plurality of fan-shaped light openings, and the shape of this fixed grating matches with the shape ofremovable slit 31a; Cooperate with fixed grating, saidremovable slit 31a also is circular, has a plurality of fan-shaped light openings;Bayonet socket 21a bottom is fixed in the substrate, and is positioned at the circumferential edges of fixed grating, and circularremovable slit 31a can rotate by the circumferencial direction alongremovable slit 31a inbayonet socket 21a; The quantity of saidmovable electrode 32a, fixedelectorde 33a and fixedelectorde 34a is respectively four, on the circumference of saidremovable slit 31a, distributes symmetrically.Fixedelectorde 33a and fixedelectorde 34a lay respectively at the both sides of said movable electrode 32a.The end ofmovable electrode 32a fixedly is electrically connected with the circumferential edges of theremovable slit 31a of said circle.

When applying certain voltage for each electrode through mems switch; Make when having electric potential difference betweenfixed electorde 33a, 34a, themovable electrode 32a; The MEMS light valve can rotate under the effect of electrostatic force; Thereby can control the degree of agreement of the light openings and the light openings on theremovable slit 31a of fixed grating, the printing opacity of control fixed grating.The principle of MEMS light valve is not elaborated at this.

Fig. 4 is the floor map of the MEMS light valve of another specific embodiment, and with reference to figure 4, the said fixed grating of this specific embodiment is fan-shaped (not shown), has the light openings of a plurality of strips, and the shape of this fixed grating matches with the shape ofremovable slit 31b;Removable slit 31b is fan-shaped, has the light openings (among the figure not label) of a plurality ofstrips.Bayonet socket 21b bottom is fixed in the substrate, is positioned at the both sides on two circular arc limits of said fan-shaped fixed grating, said fan-shapedremovable slit 31b can be in saidbayonet socket 21b along the scallop rotation ofremovable slit 31b; The end ofmovable electrode 32b fixedly is electrically connected with the short circular arc limit of said fan-shaped removable slit 31b.Wherein, fixedelectorde 33b, 34b lay respectively at the both sides of saidmovable electrode 32b.

When applying certain voltage for each electrode through mems switch; Make when having electric potential difference betweenfixed electorde 33b, 34b, themovable electrode 32b; The MEMS light valve can rotate under the effect of electrostatic force; Thereby can control the degree of agreement of the light openings and the light openings on theremovable slit 31b of fixed grating, the printing opacity of control fixed grating.The principle of MEMS light valve is not elaborated at this.

More than just list the shape of having enumerated limited fixed grating and MEMS grating; Those skilled in the art can learn the change along with fixed grating 20 and removable slit 31 shapes according to essence of the present invention, and corresponding movable electrode, fixed electorde shaped position will and then change.

Fig. 5 is a mems switch structural representation in the display device of MEMS light valve in the present embodiment.As shown in Figure 5, comprisesubstrate 101, be positioned at thethird electrode 1083 in the saidsubstrate 101 and be positioned atfirst electrode 104 ofthird electrode 1083 both sides, saidthird electrode 1083 is positioned at the surface ofmedium block 1084, and promptly saidthird electrode 1083 has contact projection; Lay respectively at the supportingsection 1081 of first electrode, 104 both sides; Be positioned at firstdielectric layer 103 in saidthird electrode 1083,first electrode 104 and supportingsection 1081 gaps, said firstdielectric layer 103 and saidthird electrode 1083,first electrode 104 and supportingsection 1081 flush.

Said mems switch also comprises and is positioned at said firstinterlayer dielectric layer 103 surfaces, and theconductive layer 1082 that is oppositely arranged with saidfirst electrode 104 and third electrode 1083.Particularly, the two ends of saidconductive layer 1082 are electrically connected with supportingsection 1081 respectively, and the saidconductive layer 1082 andfirst electrode 104 are formed with cavity with third electrode 1083.Said supportingsection 1081 constitutessecond electrode 108 withconductive layer 1082.

Further, saidfirst electrode 104 surfaces also are formed withseparation layer 107, electrically contact with saidfirst electrode 104 to avoid said conductive layer 1082.Further, said mems switch surface also is formed with seconddielectric layer 109.

In the present embodiment, saidfirst electrode 104 is positioned at the both sides ofthird electrode 1083, and as other embodiment, saidfirst electrode 104 can also be positioned at a wherein side of saidthird electrode 1083.

Third electrode 1083 is positioned at the surface of saidmedium block 1084 described in the embodiment shown in Figure 5, has contact projection with respect to saidsecond electrode 108 surfaces.As other embodiment, saidthird electrode 1083 can also only be positioned on themedium block 1084 andsecond electrode 108 surface in opposite directions, and saidthird electrode 1083 is non-raised position.Be implemented under the situation of electrostatic force, saidsecond electrode 108 electrically contacts with third electrode 1083.Remake and be other embodiment, saidthird electrode 1083 can also be other shapes and structure, and under the situation that is implemented in electrostatic force, saidsecond electrode 108 electrically contacts withthird electrode 1083.

Be illustrated in figure 6 as the vertical view of mems switch structure shown in Figure 5, comprise: be positioned atfirst electrode 104 of saidthird electrode 1083 both sides, and lay respectively at the supportingsection 1081 of second electrode of saidfirst electrode 104 both sides.Wherein, saidfirst electrode 104,third electrode 1083 and supportingsection 1081 tops also are formed with theconductive layer 1082 of second electrode, and saidconductive layer 1082 is electrically connected with said supporting section 1081.Saidconductive layer 1082 has constitutedsecond electrode 108 with supporting section 1081.Wherein, saidthird electrode 1083 has contact projection (not shown), and said contact projection is provided with respect to theconductive layer 1082 of said second electrode.

In conjunction with Fig. 2, Fig. 5 and Fig. 6 the connected mode and the principle of work of mems switch and MEMS light valve are described.Particularly, said mems switch is electrically connected with said MEMS light valve throughsecond electrode 108 orthird electrode 1083, and particularly, saidthird electrode 1083 is electrically connected with the drive electrode 005 of said MEMS light valve.With 006 of the grating electrode that said drive electrode 005 is oppositely arranged can ground connection or other non zero potential.

In the present embodiment; Whenfirst electrode 104 andsecond electrode 108 are applied a potential difference (PD); Like said potential difference (PD) scope is 2～50V, andfirst electrode 104,second electrode 108 have the xenogenesis electric charge, and making wins produces electrostatic force between theelectrode 104 and second electrode 108.Under the effect of electrostatic force,conductive layer 1082 downwarpings thatfirst electrode 104 attractssecond electrode 108 near, contact with the contact projection ofthird electrode 1083 until said conductive layer 1082.At this moment,second electrode 108 is sent to the MEMS light valve drive electrode 005 that is electrically connected withthird electrode 1083 throughthird electrode 1083 with electric signal, thus the open and close of control MEMS light valve.

After being sent to the drive electrode 005 that is electrically connected withthird electrode 1083 when electric signal; Because said grating electrode 006 ground connection or have the non zero potential that is not equal tothird electrode 1083 current potentials; Then be formed with potential difference (PD) between drive electrode 005 and the grating electrode 006; Be that drive electrode 005 has the xenogenesis electric charge with grating electrode 006, make to produce electrostatic force between drive electrode 005 and the grating electrode 006.Under the effect of electrostatic force, drive electrode 005 attract grating electrode 006 towards the direction of drive electrode 005 near.And then make said grating electrode 006 drive removable slit 003 towards the direction of drive electrode 005 near, and 002 of fixed grating is formed with relative displacement, and the light that sees through fixed grating 002 is carried out selective permeation.

In the present embodiment; The material offirst electrode 104,second electrode 108 andthird electrode 1083 can be selected from conducting metal or conductive non-metals, like combination arbitrarily of gold, silver, copper, aluminium, titanium, chromium, molybdenum, cadmium, nickel, cobalt, amorphous silicon, polysilicon, amorphous germanium silicon, poly-SiGe one of them or they.

As other embodiment, thethird electrode 1083 of said mems switch can also be electrically connected grating electrode 006, and accordingly, 005 of the drive electrode that is oppositely arranged with said grating electrode 006 can ground connection or is not equal to the non zero potential ofthird electrode 1083 current potentials.

The display device based on the MEMS light valve of this embodiment also comprises the storage unit that is electrically connected with said MEMS light valve and mems switch; Said storage unit is a MM CAP; Said MM CAP has two pole plates; One of them pole plate is connected between MEMS light valve and the mems switch, another pole plate ground connection.

Present embodiment also provides a kind of formation method of the display device based on the MEMS light valve, comprising: substrate at first is provided; In said substrate, form mems switch and MEMS light valve, the removable slit that said MEMS light valve includes fixed grating at least and is provided with respect to fixed grating; Wherein, said mems switch is electrically connected on the MEMS light valve, applies electric signal to the MEMS light valve through mems switch, with the relative position of removable slit and fixed grating in the control MEMS light valve.

Particularly, said mems switch and MEMS light valve can form respectively, also can in same step process flow process, form simultaneously.

As an embodiment, said mems switch and MEMS light valve are independent formation respectively.The formation method of wherein said MEMS light valve can not be described in detail with reference to prior art here.

As shown in Figure 7, the formation method of said mems switch comprises:

Execution in step S101 forms discrete first electrode, third electrode and supporting section in substrate, said third electrode has contact projection;

Execution in step S102 deposits first dielectric layer, and said first dielectric layer is filled the gap between first electrode, third electrode and supporting section, and exposes the surface of said first electrode, third electrode and supporting section at least;

Execution in step S103, deposition of sacrificial layer, said sacrifice layer covers said first electrode and third electrode, and the sacrificial layer surface of corresponding third electrode has convexity;

Execution in step S104 forms conductive layer on said sacrifice layer, said conductive layer is electrically connected with supporting section, and said conductive layer and supporting section constitute second electrode;

Execution in step S105 removes sacrifice layer, between said first electrode, second electrode and third electrode, forms cavity.

Wherein, also comprise forming the separation layer that covers said first electrode surface, and be positioned at second dielectric layer on mems switch surface.Particularly, said separation layer electrically contacts between second electrode and first electrode for preventing, said second dielectric layer is positioned on the metal surface of electrode of said mems switch, to avoid the metal surface of exposed electrode.

Wherein, said first electrode is positioned at the one or both sides of said third electrode, and the material of said first electrode, second electrode and third electrode is conducting metal or conductive non-metals.And said third electrode has contact projection, promptly makes said third electrode surface be higher than said first electrode surface.

Particularly; Second electrode of said mems switch or third electrode and MEMS light valve are electrically connected; When the potential difference (PD) scope of first electrode and second electrode is 2～50V; Said conductive layer is drawn close to third electrode under the effect of electrostatic force, makes said conductive layer contact with the contact projection of third electrode, electric signal is transferred to the MEMS light valve that is electrically connected with mems switch.In the present embodiment, said third electrode and MEMS light valve are electrically connected.

Simultaneously, when conductive layer contacted with the contact projection of third electrode, the separation layer of said first electrode surface can avoid said conductive layer and said first electrode to electrically contact.

As other embodiment, said mems switch and MEMS light valve can form in same step process flow process simultaneously.As shown in Figure 8, comprising:

Execution in step S201 provides substrate, in said substrate, forms fixed grating;

Execution in step S202 forms interlayer dielectric layer on said fixed grating;

Execution in step S203, the drive electrode of first electrode, third electrode, supporting section and the MEMS light valve of formation mems switch on interlayer dielectric layer, said third electrode has contact projection;

Execution in step S204 deposits first dielectric layer, and said first dielectric layer is filled the gap between first electrode, third electrode, supporting section and drive electrode, and exposes the surface of said first electrode, third electrode, supporting section and drive electrode at least;

Execution in step S205, at the said first dielectric layer surface deposition sacrifice layer, said sacrifice layer exposes supporting section and drive electrode;

Execution in step S206 forms the conductive layer of mems switch and the removable slit of MEMS light valve on said sacrifice layer, said conductive layer and supporting section constitute second electrode;

Execution in step S207 removes sacrifice layer, between said first electrode, second electrode and third electrode, forms first cavity, and said removable slit is with respect to the fixed grating setting, and is formed with second cavity with interlayer dielectric layer.

Fig. 9 to Figure 22 is the formation method structural representation based on the display device of MEMS light valve of one embodiment of the invention.As shown in Figure 9,substrate 200 is provided; Saidsubstrate 200 is a glass substrate; Be formed with the backlight (not shown) in the saidsubstrate 200; And backlight comprises red-light source, blue light source and green-light source; Said red-light source, blue light source and green-light source can be provided by blue-ray LED, red-light LED and green light LED respectively; Also can provide through laser, said laser comprises redgreenblue laser.

Shown in figure 10, insubstrate 200, form fixed grating 201, it is following specifically to form technology: insubstrate 200, form conductive layer with vacuum sputtering; On said conductive layer, form the first photoresist layer (not shown), graphical said first photoresist layer defines the fixed grating figure, and said fixed grating figure includes shading light part and light transmission part; With patterned first photoresist layer is mask, with the dry etching method along the fixed grating pattern etching to exposingsubstrate 200, form fixed grating 201.The light that being positioned at the backlight ofsubstrate 200 provides can appear through the light transmission part offixed grating 201.

In the present embodiment, the material of said fixed grating 201 also can be a non-conducting material, get final product so long as can completely cut off the light-proof material of light, for example, unadulterated polysilicon.

Shown in figure 11, on said fixed grating 201, forminterlayer dielectric layer 202, the formation method is: onfixed grating 201, form dielectric layer with chemical vapour deposition technique, said dielectric layer is filled the light transmission part of full fixed grating 201 simultaneously; Utilize the said dielectric layer of chemical mechanical milling method planarization, forminterlayer dielectric layer 202.

In the present embodiment, saidinterlayer dielectric layer 202 is formed by transparent material, like SiO₂, SiN, SiON or SiOC; Light can see throughinterlayer dielectric layer 202.

Shown in figure 12, formmedium block 2021 on saidinterlayer dielectric layer 202 surfaces.Subsequent technique will form the third electrode of mems switch on the surface that saidmedium block 2021 exposes.

Shown in figure 13, on saidinterlayer dielectric layer 202, form some electrodes.Particularly, said electrode package containsfirst electrode 205 andthird electrode 2042, supporting section 2041.Wherein, saidfirst electrode 205 is positioned at the both sides of saidthird electrode 2042, and as other embodiment, saidfirst electrode 205 can also only be positioned at a side of third electrode 2042.Said supportingsection 2041 lays respectively at the both sides of said first electrode 205.Saidthird electrode 2042 is formed at saidmedium block 2021 surfaces, so saidthird electrode 2042 has contact projection.

Electrode also comprises 301 and second drive electrode bottom, firstdrive electrode bottom 302 that is positioned at first electrode, 205 1 sides.301 and second drive electrode bottom, said firstdrive electrode bottom 302 lays respectively at the both sides of fixed grating light transmission part.

301 and second drive electrode bottom, said firstdrive electrode bottom 302 is the drive electrode bottom of MEMS light valve part, and saidfirst electrode 205 andthird electrode 2042, the secondelectrode supporting section 2041 are the counterpart of mems switch.In the present embodiment; In forming process; Saidthird electrode 2042 is a status of electrically connecting with the MEMS light valve; Concrete saidthird electrode 2042 is a status of electrically connecting with said firstdrive electrode bottom 301, makes said firstdrive electrode bottom 301 can receive the electric signal ofthird electrode 2042, to reach the control of mems switch to the MEMS light valve.

The concrete technology that forms is: with physical vaporous deposition atinterlayer dielectric layer 202 surface deposition metal materials; On said metal material, form the second photoresist layer (not shown), and define discrete figure; With second photoresist layer is mask, and the said discrete pattern etching metal material in edge is to exposinginterlayer dielectric layer 202; Remove second photoresist layer, form discrete electrode, includefirst electrode 205 andthird electrode 2042, supportingsection 2041, saidthird electrode 2042 has contact projection.

In the present embodiment, the material of above-mentioned discrete electrodes can be one of them or combination wherein such as conducting metal such as gold, silver, copper, aluminium, titanium, chromium, molybdenum, cadmium, nickel, cobalt; Also can be conductive non-metals, like amorphous silicon, polysilicon, amorphous germanium silicon, poly-SiGe or the like; Can also conducting metal and conductive non-metals combination.

Shown in figure 14, deposition forms firstdielectric layer 206, and said firstdielectric layer 206 is positioned at the gap of above-mentioned some electrodes, and exposes the surface of above-mentioned electrode at least.Said electrode comprisesfirst electrode 205,third electrode 2042, supportingsection 2041 and 301, second drive electrode bottom, first drive electrode bottom 302.Wherein, saidthird electrode 2042 can also expose the side of part.

Further, comprise that also formation is covered in theseparation layer 207 on saidfirst electrode 205 surfaces.The purpose that forms saidseparation layer 207 is to avoid second electrode of follow-up formation andfirst electrode 205 to electrically contact.In the present embodiment, the saidseparation layer 207 and firstdielectric layer 206 are that same depositing operation forms, and as other embodiment, can also form firstdielectric layer 206 andseparation layer 207 successively respectively through two step depositing operations.

In the present embodiment, firstdielectric layer 206 is a transparent material, monox for example, and light can see through.Theseparation layer 207 that coversfirst electrode 205 can be selected the material of differing dielectric constant according to the actual voltage that is applied between first electrode and second electrode, such as SiO₂, SiN, SiON or SiOC.

Shown in figure 15, on firstdielectric layer 206, form the first sacrifice layer 208a.The saidfirst sacrifice layer 208a covers the structure except that supportingsection 2041,301 and second drive electrode bottom, first drive electrode bottom 302.Be that the saidfirst sacrifice layer 208a is coated withfirst electrode 205 andseparation layer 207, cover first dielectric layer, 206 surfaces between supportingsection 2041,301 and second drive electrode bottom, firstdrive electrode bottom 302 simultaneously.

The material of the saidfirst sacrifice layer 208a is an amorphous carbon, and the technology that specifically forms thefirst sacrifice layer 208a is following: on firstdielectric layer 206, form the sacrifice layer that covers firstdielectric layer 206 andseparation layer 207 with chemical vapour deposition technique; On said sacrifice layer, form the 3rd photoresist layer; Graphical afterwards the 3rd photoresist layer that forms; Be mask with patterned the 3rd photoresist layer then, etching is removed the sacrifice layer that not graphical the 3rd photoresist layer covers, and forms thefirst sacrifice layer 208a of predetermined pattern.

Shown in figure 16, form thesecond sacrifice layer 208b, the saidsecond sacrifice layer 208b covers the part surface of the first sacrifice layer 208a.The saidfirst sacrifice layer 208a and thesecond sacrifice layer 208b have constitutedsacrifice layer 208 jointly.The material of the saidsecond sacrifice layer 208b also is an amorphous carbon, and its formation method is conventional chemical vapour deposition technique.

Shown in figure 17, depositingmetal layers 209, saidmetal level 209 are coated withsacrifice layer 208, supportingsection 2041 top surfaces, firstdrive electrode bottom 301 top surfaces and second drive electrode bottom, 302 top surfaces.Saidsacrifice layer 208 comprises thefirst sacrifice layer 208a and thesecond sacrifice layer 208b; Saidmetal level 209 also contacts and is electrically connected with the secondelectrode supporting section 2041 of mems switch, and saidmetal level 209 also contacts and is electrically connected with seconddrive electrode bottom 302 with firstdrive electrode bottom 301 of MEMS light valve simultaneously.

Shown in figure 18, onmetal level 209, form seconddielectric layer 210, saidsecond dielectric layer 210 covers saidmetal level 209 fully.

Shown in figure 19; The saidmetal level 209 and seconddielectric layer 210 are carried out etching; The removable slit part of formation between 301 and second drive electrode bottom, firstdrive electrode bottom 302, said removable slit partly includes grating electrode 312,316 and removable slit 313,314,315.Said removable slit 313,314, the gap between 315 will be as the light transmission part of removable slit.The removable slit 313,314,315 of said grating electrode 312,316 and said MEMS light valve is a status of electrically connecting.

Also be formed with simultaneously baredend 311 on firstdrive electrode bottom 301, and seconddrive electrode bottom 302 on bared end 317.Said firstdrive electrode bottom 301 constitutes first drive electrode with baredend 311, and said seconddrive electrode bottom 302 constitutes second drive electrode with baredend 317.

Shown in figure 20, etching is removed the metal level between the supportingsection 2041 andfirst drive electrode 311, makes said supportingsection 2041 electrically isolate from said first drive electrode 311.Form theconductive layer 2043 of mems switch simultaneously, saidconductive layer 2043 and the supportingsection 2041 that is electrically connected with it constitute second electrode.

Saidconductive layer 2043 is coated with thesecond sacrifice layer 208b, and the two ends of saidconductive layer 2043 are electrically connected with supportingsection 2041 respectively.Wherein, Saidconductive layer 2043 has contact projection; Under the effect of the electrostatic force betweenfirst electrode 205 and second electrode; Saidconductive layer 2043 meeting downwarpings make said contact projection be electrically connected with saidthird electrode 2042, electric signal are transferred to the MEMS light valve that is electrically connected withthird electrode 2042.

Shown in figure 21, removefirst sacrifice layer 208a and the 208b, form first cavity 510 betweenfirst electrode 205 and second electrode; Also be formed with second cavity 520 between theinterlayer dielectric layer 206 on fixed grating surface and the removable slit part simultaneously.

The formation method based on the display device of MEMS light valve of this embodiment also comprises and forms the storage unit that is electrically connected with said MEMS light valve and mems switch; Said storage unit is a MM CAP; Said MM CAP has two pole plates; One of them pole plate is connected in MEMS light valve and mems switch, another pole plate ground connection.

Particularly; The principle of work of said display device based on the MEMS light valve comprises:first electrode 205 is applied first current potential, to second electrode, comprise thatconductive layer 2043 and supportingsection 2041 apply second current potential; Saidconductive layer 2043 is under the effect of electrostatic force; Towards 205 bendings of first electrode, make the contact projection of saidconductive layer 2043 contact with saidthird electrode 2042, then saidthird electrode 2042 has second current potential.Accordingly, first drive electrode that is electrically connected with saidthird electrode 2042 has second current potential, and thegrating electrode 312 of simultaneously said removable slit part is a ground state, or is different from other current potentials of second current potential.

Then; Between said first drive electrode andgrating electrode 312, be formed with potential difference (PD); When being 2～50V like the potential difference (PD) scope; Then first drive electrode and removable slit are formed with electrostatic force; Said electrostatic force makes removable slit part (comprising grating electrode 312,316 and removable slit 313,314,315) move to first drive electrode, thereby makes and be formed with relative displacement between said removable slit part and the fixed grating below it, so that the light that fixed grating is appeared is selected.When the light transmission part of the light transmission part of fixed grating and removable slit had lap, the light that said backlight provides can appear removable slit through fixed grating.

In the present embodiment; Under the effect of electrostatic force; Said removable slit part (comprising grating electrode 312,316 and removable slit 313,314,315) moves towards the direction of first drive electrode, as other embodiment, in order to make said removable slit move towards the direction of second drive electrode; Can form the mems switch of the opposite side that is connected with said drive electrode, the concrete structure of said mems switch and formation method can be with reference to aforementioned.

Further; In the present embodiment; For making said removable slit part move towards the first drive electrode direction, said first drive electrode is electrically connected withthird electrode 2042, andgrating electrode 312 ground connection of said removable slit part or other are different from the current potential of second current potential.As other embodiment, can also saidthird electrode 2042 be electrically connected withgrating electrode 312, make saidgrating electrode 312 have second current potential, the said first drive electrode ground connection of while or other are different from the current potential of second current potential.

In the present embodiment, mems switch is electrically connected throughthird electrode 2042 and MEMS light valve, as other embodiment, can also pass through second electrode, comprises thatconductive layer 2043 and supportingsection 2041 and MEMS light valve are electrically connected.

Through adopting mems switch simple in structure to substitute traditional T FT switch; Apply electric signal to the MEMS light valve through mems switch; Relative position with removable slit and fixed grating in the control MEMS light valve; Said mems switch is simple in structure, has simplified the manufacturing process of said display device greatly, reduces manufacturing cost.

Said mems switch comprises first electrode and third electrode, reaches second electrode that is oppositely arranged with third electrode, whether contacts with third electrode through second electrode and controls the MEMS light valve, thereby realize the control to the display device shows signal.Said mems switch is simple in structure, has simplified the manufacturing process of said display device greatly, reduces manufacturing cost.

The formation method based on the display device of MEMS light valve that this embodiment provides also forms mems switch when forming the MEMS light valve, utilize said mems switch control MEMS light valve, thereby realizes the control of display device shows signal.Said MEMS is simple in structure, has simplified the manufacturing process of said display device greatly, reduces manufacturing cost.

Though the present invention discloses as above, the present invention is defined in this.Any those skilled in the art are not breaking away from the spirit and scope of the present invention, all can do various changes and modification, so protection scope of the present invention should be as the criterion with claim institute restricted portion.

Claims (20)

1. the display device based on the MEMS light valve is characterized in that, comprising:

Substrate;

Be positioned at the mems switch and the MEMS light valve of said substrate surface, the removable slit that said MEMS light valve includes fixed grating at least and is provided with respect to fixed grating;

Said mems switch is electrically connected on the MEMS light valve, applies electric signal to the MEMS light valve through mems switch, with the relative position of removable slit and fixed grating in the control MEMS light valve;

Said mems switch comprises: first electrode and third electrode; With respect to second electrode of first electrode and third electrode setting, said second electrode comprises supporting section and the conductive layer that is connected with supporting section, and wherein, third electrode has contact projection with respect to the surface of conductive layer; When first electrode and second electrode had potential difference (PD), said conductive layer was drawn close to third electrode under the effect of electrostatic force, makes the contact projection of said conductive layer and third electrode electrically contact, with through mems switch control MEMS light valve.

2. the display device based on the MEMS light valve according to claim 1 is characterized in that said first electrode lays respectively at the one or both sides of third electrode.

3. the display device based on the MEMS light valve according to claim 1 is characterized in that, is positioned at said first electrode and the second interelectrode cavity.

4. the display device based on the MEMS light valve according to claim 1 is characterized in that, said second electrode or third electrode and MEMS light valve are electrically connected.

5. the display device based on the MEMS light valve according to claim 1 is characterized in that, when the potential difference (PD) scope of first electrode and second electrode was 2 ~ 50V, the contact projection of said conductive layer and third electrode electrically contacted.

6. the display device based on the MEMS light valve according to claim 1 is characterized in that, the material of said first electrode, second electrode and third electrode is conducting metal or conductive non-metals.

7. the display device based on the MEMS light valve according to claim 1 is characterized in that, said MEMS light valve also comprises:

The drive electrode that is provided with respect to removable slit, and the grating electrode that is connected with said removable slit, when said drive electrode and grating electrode had potential difference (PD), moved with respect to fixed grating towards the drive electrode direction on said removable slit edge.

8. the display device based on the MEMS light valve according to claim 7 is characterized in that said drive electrode is positioned at the one or both sides of removable slit.

9. the display device based on the MEMS light valve according to claim 1 is characterized in that, also comprises the storage unit that is electrically connected with said MEMS light valve and mems switch.

10. the display device based on the MEMS light valve according to claim 9 is characterized in that, said storage unit is a MM CAP, and said MM CAP has two pole plates, and one of them pole plate is connected between MEMS light valve and the mems switch, another pole plate ground connection.

11. the formation method based on the display device of MEMS light valve is characterized in that, may further comprise the steps:

Substrate is provided;

In said substrate, form mems switch and MEMS light valve, the removable slit that said MEMS light valve includes fixed grating at least and is provided with respect to fixed grating;

Said mems switch is electrically connected on the MEMS light valve, applies electric signal to the MEMS light valve through mems switch, with the relative position of removable slit and fixed grating in the control MEMS light valve;

Wherein, the formation method of said mems switch comprises:

In substrate, form first electrode, third electrode and supporting section, wherein, said third electrode has contact projection;

Deposit first dielectric layer, said first dielectric layer is filled the gap between first electrode, third electrode and supporting section, and exposes the surface of first electrode, third electrode and supporting section at least;

Deposition of sacrificial layer, said sacrifice layer cover said first electrode and third electrode, and the sacrificial layer surface of corresponding third electrode has convexity;

On said sacrifice layer, form conductive layer, said conductive layer is electrically connected with supporting section, and said conductive layer and supporting section constitute second electrode;

Remove sacrifice layer, between said first electrode, second electrode and third electrode, form cavity.

12. formation method according to claim 11 is characterized in that said first electrode is positioned at the one or both sides of said third electrode.

13. formation method according to claim 11 is characterized in that, comprises, is electrically connected said second electrode and MEMS light valve or is electrically connected said third electrode and the MEMS light valve.

14. formation method according to claim 11 is characterized in that, when the potential difference (PD) scope of first electrode and second electrode was 2 ~ 50V, said contact projection contacted with third electrode.

15. formation method according to claim 11 is characterized in that, the material of said first electrode, second electrode and third electrode is conducting metal or conductive non-metals.

16. formation method according to claim 11 is characterized in that, said removable slit is positioned at a side of fixed grating, and the opposite side that said formation method also is included in said fixed grating forms backlight.

17. the formation method based on the display device of MEMS light valve is characterized in that, may further comprise the steps:

Substrate is provided;

In said substrate, form mems switch and MEMS light valve, the removable slit that said MEMS light valve includes fixed grating at least and is provided with respect to fixed grating;

Said mems switch is electrically connected on the MEMS light valve, applies electric signal to the MEMS light valve through mems switch, with the relative position of removable slit and fixed grating in the control MEMS light valve;

Wherein, the step that forms said mems switch and MEMS light valve simultaneously comprises:

Substrate is provided, in said substrate, forms fixed grating;

On said fixed grating, form interlayer dielectric layer;

On interlayer dielectric layer, form the drive electrode of first electrode, third electrode, supporting section and the MEMS light valve of mems switch, said third electrode has contact projection;

Deposit first dielectric layer, said first dielectric layer is filled the gap between first electrode, third electrode, supporting section and drive electrode, and exposes the surface of said first electrode, third electrode, supporting section and drive electrode at least;

At the said first dielectric layer surface deposition sacrifice layer, said sacrifice layer exposes supporting section and drive electrode; The conductive layer and the removable slit of MEMS light valve, said conductive layer and the supporting section that on said sacrifice layer, form mems switch constitute second electrode;

Remove sacrifice layer, between said first electrode, second electrode and third electrode, form first cavity, said removable slit is with respect to the fixed grating setting, and is formed with second cavity with interlayer dielectric layer.

18. formation method according to claim 17 is characterized in that said first electrode is positioned at the one or both sides of said third electrode.

19. formation method according to claim 17 is characterized in that, also comprises being electrically connected said second electrode and MEMS light valve or being electrically connected said third electrode and the MEMS light valve.

20. formation method according to claim 17 is characterized in that, also comprises the formation grating electrode, said grating electrode is electrically connected with the removable slit of said MEMS light valve.

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