Summary of the invention
The invention provides a kind of pressure transducer and preparation method thereof, overcome in prior art diffused silicon piezoresistive pressure sensor and adopted P-N knot isolation strain bridge and strain films, P-N junction leakage is along with temperature raises and sharply increases the pressure transducer causing based on the isolation of P-N knot and be difficult to the problem of working under higher than 80 ℃ of high-temperature conditions.
The technical scheme that technical solution problem of the present invention adopts is:
A method for making for pressure transducer, wherein, adopts following steps:
S1, provides a SOI substrate, and described SOI substrate comprises the first body silicon layer, the first insulation course, the second body silicon layer, the second insulation course and trisome silicon layer from the bottom to top;
S2, adulterates and forms resistive layer described trisome silicon layer, forms one the 3rd insulation course on described resistive layer, and the core of etching the 3rd insulation course and resistive layer forms pressure drag;
S3, the two ends of the 3rd insulation course form respectively contact hole described in etching, in described contact hole, form metal electrode;
S4, one face glass is provided, described face glass comprises through hole and cavity, described face glass is bonded on the 3rd insulation course forming after metal electrode, metal electrode described in described through-hole alignment, described cavity forms a seal chamber with the spacial alignment that forms the 3rd insulation course of pressure drag and the core of resistive layer;
S5, removes described the first body silicon layer, and the first insulation course and the second body silicon layer that etching is positioned at described pressure drag lower position form mass and pressure-bearing film, remove described the first insulation course, form chip structure;
S6, one pedestal is provided, and described benchmark comprises base, base glass plate and tinsel, described chip structure is poured into described pedestal after filling conductor in described through hole, tinsel in described pedestal is aimed in the conductor inserting in described through hole, and high temperature sintering solidifies;
S7, provides a back side glass, and described back side glass comprises backside through vias, described back side glass is bonded on the second body silicon layer of described chip structure, and described backside through vias is aimed at described mass and pressure-bearing film.
The method for making of above-mentioned pressure transducer, wherein, in described step S2, the core of etching the 3rd insulation course and resistive layer forms pressure drag, be specially: described in etching, the core of the 3rd insulation course is to described resistive layer, and spin coating photoresist, after exposure, development, described in etching, the core of photoresist and described resistive layer forms pressure drag, removes photoresist.
The method for making of above-mentioned pressure transducer, wherein, in described step S2, the core of etching the 3rd insulation course and resistive layer forms pressure drag, be specially: spin coating photoresist on described the 3rd insulation course, exposure, develop after, the core of photoresist, described the 3rd insulation course and described resistive layer forms pressure drag described in etching, removes photoresist.
The method for making of above-mentioned pressure transducer, wherein, the core quantity of formation of etching the 3rd insulation course and resistive layer is more than or equal to 2 even number pressure drag.
The method for making of above-mentioned pressure transducer, wherein, the method for making of described face glass is: a face glass plate is provided, in the bottom centre position formation one of the described face glass plate cavity suitable with forming the 3rd insulation course of pressure drag and the core position of resistive layer, in the both sides of described face glass plate, form respectively through hole suitable with described metal electrode position and that described metal electrode can all be come out, obtain described face glass.
The method for making of above-mentioned pressure transducer, wherein, the method for making of described back side glass is: a back glass plate is provided, in the center of described back glass plate, form one with described mass and pressure-bearing film location is suitable and backside through vias that described mass and pressure-bearing film can all be come out, obtain described back side glass.
The method for making of above-mentioned pressure transducer, wherein, the method for making of described pedestal is: a base and a base glass plate are provided, by sintering connection metal silk on described base glass plate, make described one end wiry vertically through described base glass plate; Base glass plate sintering after connection metal silk is connected in to nearly bottom opening place in described base, makes the described other end wiry through the bottom opening of described base; The surface of the base glass plate in being connected to described base applies one deck glass paste, obtains described pedestal.
The method for making of above-mentioned pressure transducer, wherein, in described step S2, carries out the boron ion doping of high dose to described trisome silicon layer, form dense boron resistive layer.
A method for making for pressure transducer, wherein, adopts following steps:
S1, provides a SOI substrate, and described SOI substrate comprises the first body silicon layer, the first insulation course, the second body silicon layer, the second insulation course and trisome silicon layer from the bottom to top;
S2, adulterates and forms resistive layer described trisome silicon layer, forms one the 3rd insulation course on described resistive layer, and the core of etching the 3rd insulation course and resistive layer forms pressure drag;
S3, the two ends of the 3rd insulation course form respectively a contact hole described in etching, in described contact hole, form metal electrode;
S4, one face glass is provided, described face glass comprises through hole and cavity, described face glass is bonded on the 3rd insulation course forming after metal electrode, metal electrode described in described through-hole alignment, described cavity forms a seal chamber with the spacial alignment that forms the 3rd insulation course of pressure drag and the core of resistive layer;
S5, removes described the first body silicon layer, and the first insulation course and the second body silicon layer that etching is positioned at described pressure drag lower position form mass and pressure-bearing film, remove described the first insulation course;
S6, forms layer of metal layer in the sidewall of described face glass, described through hole and the surface of bottom and described metal electrode;
S7, provides a back side glass, and described back side glass comprises backside through vias, and described back side glass is bonded on the lower surface of described the second body silicon layer, makes described backside through vias aim at described mass and pressure-bearing film, removes described metal level, forms chip structure;
S8, one pedestal is provided, and described benchmark comprises base, base glass plate and tinsel, described chip structure is poured into described pedestal after filling conductor in described through hole, tinsel in described pedestal is aimed in the conductor inserting in described through hole, and high temperature sintering solidifies.
The method for making of above-mentioned pressure transducer, wherein, in described step S2, the core of etching the 3rd insulation course and resistive layer forms pressure drag, be specially: described in etching, the core of the 3rd insulation course is to described resistive layer, and spin coating photoresist, after exposure, development, described in etching, the core of photoresist and described resistive layer forms pressure drag, removes photoresist.
The method for making of above-mentioned pressure transducer, wherein, in described step S2, the core of etching the 3rd insulation course and resistive layer forms pressure drag, be specially: spin coating photoresist on described the 3rd insulation course, exposure, develop after, the core of photoresist, described the 3rd insulation course and described resistive layer forms pressure drag described in etching, removes photoresist.
The method for making of above-mentioned pressure transducer, wherein, the core quantity of formation of etching the 3rd insulation course and resistive layer is more than or equal to 2 even number pressure drag.
The method for making of above-mentioned pressure transducer, wherein, the method for making of described face glass is: a face glass plate is provided, in the bottom centre position formation one of the described face glass plate cavity suitable with forming the 3rd insulation course of pressure drag and the core position of resistive layer, in the both sides of described face glass plate, all form through hole suitable with described metal electrode position and that described metal electrode can all be come out, obtain described face glass.
The method for making of above-mentioned pressure transducer, wherein, the method for making of described back side glass is: a back glass plate is provided, in the center of described back glass plate, form one with described mass and pressure-bearing film location is suitable and backside through vias that described mass and pressure-bearing film can all be come out, obtain described back side glass.
The method for making of above-mentioned pressure transducer, wherein, the method for making of described pedestal is: a base and a base glass plate are provided, by sintering connection metal silk on described base glass plate, make described one end wiry vertically through described base glass plate; Base glass plate sintering after connection metal silk is connected in to nearly bottom opening place in described base, makes the described other end wiry through the bottom opening of described base; The surface of the base glass plate in being connected to described base applies one deck glass paste, obtains described pedestal.
The method for making of above-mentioned pressure transducer, wherein, in described step S2, carries out the boron ion doping of high dose to described trisome silicon layer, form dense boron resistive layer.
A pressure transducer, wherein, comprises pedestal and is arranged at the chip in described pedestal; Described chip comprises middle layer, the back side glass being connected with the upper surface in described middle layer, and the face glass being connected with the lower surface in described middle layer;
Described middle layer comprises the second body silicon layer, the second insulation course, resistive layer and the 3rd insulation course from top to bottom successively, the core of described the 3rd insulation course and described resistive layer is provided with a fluting, in described fluting, be provided with pressure drag, the two ends of described the 3rd insulation course are respectively equipped with metal electrode; The part that is positioned at described pressure drag top in described the second body silicon layer comprises two symmetrical inverted trapezoidal openings, is located at the pressure-bearing film of described inverted trapezoidal opening below, and is located at two masses between inverted trapezoidal opening;
The upper surface middle of described face glass is provided with a cavity, described cavity and described fluting form the vacuum cavity of the described pressure drag of sealing, the two ends of described face glass are also respectively equipped with the through hole suitable with described metal electrode position, described through hole is aimed at described metal electrode, is also provided with conductor in described through hole;
The center of described back side glass is provided with and the suitable backside through vias of described pressure-bearing film and described mass position, and described backside through vias all comes out described pressure-bearing film and described mass;
Described pedestal comprises the base of upper and lower opening and hollow, be arranged at the base glass plate of nearly bottom in described base, and be arranged at the tinsel on described base glass plate, described tinsel is perpendicular to described base glass plate, described one end wiry is passed described base glass plate and is inserted in the conductor in described through hole, and the described other end wiry stretches out from the under shed of described base.
Above-mentioned pressure transducer, wherein, described pressure drag is for adopting the single layer structure of resistive layer material, and its thickness is identical with described resistive layer.
Above-mentioned pressure transducer, wherein, described pressure drag is for to adopt the double-decker of resistive layer material and the 3rd insulating layer material respectively, and its thickness is identical with the 3rd insulation course with described resistive layer respectively.
The technical program tool has the following advantages or beneficial effect:
Pressure transducer of the present invention is based on SOI Silicon-On-Insulator substrate, in front, by photoetching and lithographic technique, form wheatstone bridge structure, bulk silicon etching technology mineralization pressure sensitive membrane for the back side, and the anode linkage by positive si-glass forms vacuum cavity, the back side adopts silicon on glass bonding to reach stress equilibrium, and device adopts unique single-chip package mode to reach high reliability.
In the method for making of MEMS pressure transducer of the present invention, pass through to adopt soi process, can guarantee that formed diffuse si piezoresistance, pressure sensor can work under hot environment, especially can between 175 ℃, work at-55 ℃, can be widely used in various industrial automatic control environment, numerous industries such as design petroleum pipe line, water conservancy and hydropower, railway traffic, intelligent building, production automatic control, Aero-Space, petrochemical industry, oil well, electric power, boiler.
Embodiment
The invention provides a kind of pressure transducer and preparation method thereof, relate in particular to a kind of MEMS pressure transducer that can normally use in high temperature (higher than 80 ℃) environment.It should be appreciated by those skilled in the art, pressure transducer of the present invention is only not limited to and normally uses in the environment higher than 80 ℃.It should be noted that, pressure transducer of the present invention can work between-55 ℃ to 175 ℃, and can be applicable in various industrial automatic control environment, as numerous industries such as design petroleum pipe line, water conservancy and hydropower, railway traffic, intelligent building, production automatic control, Aero-Space, petrochemical industry, oil well, electric power, boilers.
Pressure transducer of the present invention is based on SOI Silicon-On-Insulator substrate, front at device forms wheatstone bridge configuration by photoetching and lithographic technique, the back side of device adopts bulk silicon etching technology mineralization pressure sensitive membrane, and the positive anode linkage by si-glass forms vacuum cavity, the back side adopts silicon on glass bonding to reach stress equilibrium, positive dry film technique and the metal sputtering technique of adopting forms metal electrode, and device adopts unique single-chip package mode to reach high reliability.
Below in conjunction with specific embodiment, pressure sensor structure of the present invention and preparation method thereof is elaborated.
Embodiment 1:
The pressure transducer of the present embodiment can consist of chip and pedestal.
The preparation of chip:
First, prepare a silicon-on-insulator (silicon on insulator, be called for short: SOI) substrate, as shown in Figure 1, this silicon-on-insulator substrate comprises the first body silicon layer 1, at upper surface covering one deck first insulation course 2 ' of the first body silicon layer 1, at upper surface covering one deck second body silicon layer 3 ' of this first insulation course 2 ', upper surface at this second body silicon layer 3 ' covers first insulating layer 4, at upper surface covering one deck trisome silicon layer 5 of the second insulation course 4.Wherein, the thickness of the first body silicon layer 1, the second body silicon layer 3 ' and trisome silicon layer 5 reduces successively; Thickness Ratio second insulation course 4 of the first insulation course 2 ' is thick, and wherein, the first insulation course 2 ' plays the effect of sheltering that stops while corroding the second body silicon layer 3 formation mass in subsequent technique.
Then, as shown in Figure 2, in above-mentioned trisome silicon layer 5, carry out dense boron doping process, so that the boron ion of high dose is doped in trisome silicon layer 5.In this step, for the doping of boron ion, can preferably adopt the mode of ion implantation technology or boiler tube diffusion to carry out.Through overdoping the trisome silicon layer after uniform dense boron ion become dense boron resistive layer 6 '.
As shown in Figure 3, prepare the upper surface that one the 3rd insulation course 7 ' covers dense boron resistive layer 6 ', to protect the dense boron resistive layer 6 ' that is positioned at its below.Wherein, the 3rd insulation course 7 ' is preferably oxide layer, for the preparation of this layer, can adopt thermal oxide growth, also can adopt chemical vapor deposition (Chemical vapor deposition, be called for short: CVD) or the method for other depositing operation methods be prepared.
Then, prepare the upper surface that one deck photoresist covers the 3rd above-mentioned insulation course 7 ', this photoresist can adopt spin coating or other processes to apply, afterwards, this photoresist is carried out to photoetching process, adopt the figuratum photomask blank of a tool to expose and developing process to this photoresist, make to form pattern in this photoresist, then the photoresistance with this pattern of take carries out etching to the 3rd insulation course 7 ' and the dense boron resistive layer 6 ' of below as mask, and make etching stopping in the upper surface of the second insulation course 4, this etching can adopt dry etching or wet etching etc.As shown in Figure 4, after over etching, two composite beds that remaining three insulation course 7 and the dense boron resistive layer 6 of formation at structure two ends forms in the 3rd insulation course 7 ' and dense boron resistive layer 6 ' and several pressure drags 71 that form between these two composite beds, the quantity of pressure drag 71 can need to be adjusted according to actual process, in the present embodiment, the quantity of pressure drag is 4.In each pressure drag, include bilevel structure, wherein, understructure is dense boron doped silicon, superstructure is insulating material.Then, remaining photoresist in photoetching process before removing, the i.e. photoresist of remaining the 3rd insulation course 7 upper surfaces after removal is covered in each pressure drag 71 top and passes through etching.
After having formed above-mentioned pressure drag 71, same, as shown in Figure 5, adopt existing photoetching, lithographic method, at the two ends of the 3rd insulation course 7, form respectively this contact hole 72 of contact hole 72(and be formed with altogether four, because Fig. 5 is cut-open view, only can see two contact holes 72).Then, deposit one composite metal electrode layer on the sidewall of the 3rd insulation course 7 and contact hole 72 and bottom, this composite metal electrode layer of etching, only remainder covers the sidewall of place, adosculation hole on the 3rd insulation course 7 and contact hole, metal electrode 8 on bottom, as shown in Figure 6, this metal electrode 8 by the first metal electrode 81 and on the second metal electrode 82 form, wherein the material of the first metal electrode 81 can preferably adopt titanium (Ti) or nickel (Ni), the material of the second metal electrode 82 can preferably adopt platinum (Pt) or chromium (Cr), and adopt the first metal electrode 81 and the second metal electrode 82 can increase the conductance of metal electrode, prevent the metal diffusion in subsequent technique simultaneously.Wherein, this composite metal electrode adopts magnetron sputtering and liftoff technique to form.
Then, as shown in Figure 7, at the top of said structure autoregistration bonding one face glass 9, this bonding is anode linkage.In the center of these face glass 9 bottoms, there is a cavity 91, the width of this cavity 91 equates with the spacing between two composite beds, and the edge of this cavity 91 is chamfering or perpendicular type design, cavity and comprise that the spacial alignment between above-mentioned two composite beds of several pressure drags is formed for sealing the seal chamber of pressure drag, sealing cavity can be vacuum or antivacuum cavity; In this face glass 9, be also provided with two through holes 92 that lay respectively at two composite bed tops, when bonding, this through hole 92 is aimed at above-mentioned metal electrode, and metal electrode 8 is come out.
Preparation for this face glass can be divided into following step: as shown in figure 20, preparation for face glass, first, the face glass plate 9 ' of one even thickness is provided, then this face glass is carried out to etching technics (dry etching or wet etching), with the central position in this face glass plate bottom, forming a top (is chamfering while adopting dry etching with chamfering or right angle, while adopting wet etching, be right angle) cavity as shown in Figure 21 91, the degree of depth of cavity 91 can need to be determined according to concrete technology.Then adopt laser technology or blasting craft to act on this face glass plate 9 ', the both sides Formation cross-section that makes to be positioned in this face glass plate 9 ' cavity 91 is similarly four for circular or polygonal through hole 92(through hole 92, and the position of position and metal electrode 8 is suitable), as shown in figure 22.
Afterwards, adopt reduction process and/or bulk silicon etching technique to remove the first body silicon layer 1, as shown in Figure 8.
Subsequently, adopt reactive ion etching (Reactive Ion Etching, be called for short: RIE) technique or wet-etching technology carry out etching to the first insulation course 2 ', control etching stopping in the lower surface of the second body silicon layer 3 ', to be formed for subsequent etching in the first insulation course 2 ', form the figure opening of pressure-bearing film and mass.In the process of etching, preferred, can first apply one deck photoresist, then by photoetching, at this photoresist, define the pattern of figure open area, and take this photoresist with this pattern and the first insulation course 2 ' is carried out to etching as mask.As shown in Figure 9, two openings 21 that are used to form pressure-bearing film and mass in the first insulation course after over etching, have been formed.
Then, the first insulation course 2 that forms opening of take carries out wet etching to the second body silicon layer 3 ' as mask, in etching process, control the degree of depth of etching, as shown in figure 10, so that form two trapezoidal grooves in the second body silicon layer 3 ', owing to there being the first insulation course 2 not being etched away to exist in the process of etching in the centre of two openings, so the body silicon between two trapezoidal grooves that form in the second body silicon layer at aperture position place is with regard to the shape of an inverted trapezoidal of self-assembling formation, the part second body silicon layer 3 of two trapezoidal groove tops forms the pressure-bearing film 31 of pressure transducer, the body silicon of an inverted trapezoidal between it partly forms the mass 32 of pressure transducer.Wherein, for the wet etching in this step, can adopt the strong base solution with highly corrosive is reaction raw materials, as potassium hydroxide solution (KOH), Tetramethylammonium hydroxide (THAM) solution etc.In addition, can also adopt ICP(Inductively Coupled Plasma, inductively coupled plasma) the dark silicon BOSCH of dry etching technique formation mass 32 and pressure-bearing film 31.
Then, total after above-mentioned technique is formed is carried out wet etching, with all insulation courses of the part that remove to expose, all remaining the first insulation courses 2 and by part the 3rd insulation course that in face glass, each through hole exposed, form structure as shown in figure 11.
As shown in figure 12; adopt the mode of metal sputtering to prepare the upper surface that layer of metal layer 10 is covered in structure shown in Figure 11; cover the sidewall surfaces of top surface He each through hole 92 of face glass 9; and cover the surface of dense boron resistive layer 6 exposures and the side surface that the 3rd insulation course 7 exposes, to play in follow-up technological process, the structure below it is carried out to the suitably effect of protection.In this step, the material of prepared metal level 10 can be preferably aluminium.
Then, back side glass 12 on bonding on the lower surface of the second body silicon layer 3 in the structure shown in Figure 13, this back side glass is covered in the lower surface of the second body silicon layer 3 except pressure-bearing film 31 and mass 32, the centre that is back side glass is formed with a backside through vias 121, and the width of this backside through vias 121 equates to distance between the right hand edge of the pressure-bearing film on right side with the left hand edge of the pressure-bearing film in left side.Wherein, the preparation for this back side glass 12 can be divided into two steps: step 1, as shown in figure 23, provides a thickness identical and smooth back glass plate 12 '; Step 2, as shown in figure 24, carries out etching to this back glass plate 12 ' and forms backside through vias 121, and the width of backside through vias 121 equates to distance between the right hand edge of the pressure-bearing film on right side with the left hand edge of the pressure-bearing film in left side.
In the process of above-mentioned back side glass 12 bondings; the metal level 10 that is positioned at chip structure upper surface is protected the structure of its below; and its meaning not had in follow-up technological process; therefore; need to remove, remove structure after this metal level as shown in figure 14.
Be more than the detailed step in the present embodiment, chip being prepared, below the method for making of pedestal described.
The preparation of pedestal:
First, one base 16 is as shown in figure 25 provided, the hollow structure that this base 16 is upper and lower opening, and its cross section is reversed convex type, then, as shown in figure 26, one base glass plate 17 is carried out to sintering with tinsel 18, this tinsel 18 is fixed perpendicular to base glass plate 17 and with this base glass plate 17, tinsel 18 is provided with four altogether, and every one metal wire 18 all has sub-fraction to pass the upper surface of described base glass plate 17, for being electrically connected to of subsequent technique and chip.Simultaneously, in the process of this sintering, need to guarantee that the spacing between tinsel 18 equates with the spacing between chip inner via hole, then, as shown in figure 27, to be fixed with the two ends of base glass plate wiry and the upper surface of base 16 inner both sides carries out sintering, the base glass plate 17 that makes base 16 and be fixed with tinsel 18 is fixed.Finally, base glass plate 17, tinsel 18 and base 16 threes are fixed together, and form pedestal.
For the pressure transducer in the present embodiment, last, need to carry out packaging technology, the chip of soon having prepared is fixed in pedestal.
This packaging technology comprises:
As shown in figure 15, in the through hole that is coated with metal electrode in chip, pour into resistant to elevated temperatures conductor 19, in this process, pour into conductor until be positioned at the surface of conductor and the top surface of face glass of through hole and flush.This resistant to elevated temperatures conductor is fluid material in the present embodiment, is preferably silver slurry.
Then, chip autoregistration is poured in pedestal, and guarantee that two one metal wires 18 in pedestal are inserted into respectively two fillings and have in the through hole of conductor 19, the surface that simultaneously guarantees the base glass plate in pedestal contacts with the surface of face glass in chip, now, carry out high temperature sintering curing process, make to form a fixed connection between pedestal and chip, after technique completes, form structure as shown in figure 16.
So far, the method for making of the pressure transducer in the present embodiment finishes completely.
Below the structure of the pressure transducer in the present embodiment is elaborated.
As shown in figure 16, the pressure transducer in the present embodiment mainly comprises chip and pedestal, and chip is positioned at the inside of pedestal, between chip and pedestal for being fixedly connected with.
Wherein, the section of pedestal is zhou duicheng tuxing, the center line that axis of symmetry is pressure transducer.Pedestal mainly comprises that base and is connected with glass wiry.Base is the container of a semi open model, and its top and bottom are for opening wide, and side is for sealing, to protect the chip being positioned at wherein; This is connected with straight base glass plate 17 and the tinsel 18 of partial fixing in this base glass plate 17 that base glass plate wiry comprises an even thickness, every 18, this metal is all fixed perpendicular to this base glass plate 17, and every one metal wire 18 all runs through this base glass plate 17.
The cross-section structure of chip is zhou duicheng tuxing, the center line that axis of symmetry is pressure transducer.Chip mainly comprises face glass 9, back side glass 12 and middle layer, the lower surface bonding in the upper surface of back side glass and middle layer, the top surface bonding in the lower surface of face glass and middle layer.Wherein, the structure in middle layer is followed successively by from the bottom to top, the second body silicon layer 3, the second insulation course 4, dense boron resistive layer 6, the 3rd insulation course 7.In the second body silicon layer 3, be provided with two pressure-bearing films 31 and a mass 32, mass 32 is positioned at the centre of the second body silicon layer 3, two pressure-bearing films 31 are positioned at the both sides of this mass 32, and about these mass 32 symmetries, the section of mass 32 is inverted trapezoidal, and what the section that is positioned at the below of each pressure-bearing film 31 was hollow out is trapezoidal; Center section at dense boron resistive layer 6 and the 3rd insulation course 7 is formed with 4 pressure drags that comprise dense boron resistance material and the 3rd insulating material, wherein, two left sides that are positioned at center line, two other is positioned at the right of center line; In face glass 9, be provided with a cavity 91, this cavity 91 makes to have certain distance between pressure drag 71 and face glass 9, the spacial alignment with pressure drag between cavity 91 and dense boron resistive layer 6 and the 3rd insulation course 7 forms the vacuum cavity of sealing, and the both sides in face glass 9 are also respectively provided with the through hole 92 that an inside is provided with conductor and metal electrode.The 3rd insulation course 7 at two ends is also respectively provided with a contact hole 72, and part covers sidewall, the metal electrode on bottom 8 of place, adosculation hole on the 3rd insulation course 7 and contact hole, this metal electrode 8 is double-decker, comprise the first metal layer 81 and the second metal level 82, metal electrode 8 and through hole 92 are aimed at, and the remaining space in this through hole 92 is filled up by conductor 19.
Pedestal is realized and being fixedly connected with of chip by the lower surface of its inner glass 17 and the upper surface sintering of face glass in chip 9.One end of tinsel 18 in pedestal is stretched in chip inner via hole 92, realizes being electrically connected between metal wire 18 and dense boron resistive layer 6.
Embodiment 2:
In the present embodiment, final formed device architecture is in the same manner as in Example 1, and difference is only in method for making.To being different from the step of embodiment 1 in the present embodiment, be elaborated below.
In the method for making of the present embodiment, with embodiment 1 difference be, when the preparation technology of chip proceeds to structure as shown in figure 11, the processing step of glass bonding in the back side in embodiment 1 is adjusted in the packaging technology of chip and pedestal and gone to carry out, and the final step that the step of this back side glass bonding is adjusted to packaging technology is carried out, the advantage of doing is like this, the bonding of back side glass and chip in the end chip and pedestal is sintered together and just carries out afterwards, the face glass of chip now and through hole are sintered together with pedestal, therefore, before bonding, without the front covering metal layer to chip, protected overleaf, like this for the processing step in embodiment 1, just omitted as Figure 12, covering metal layer shown in 14, remove the processing step of metal level, and only at last increase by the one step back side glass of technique and the bonding of chip.
Concrete steps are:
As shown in Fig. 1~11, the processing step of the method for the present embodiment before forming Figure 11 structure is identical with embodiment 1, can, referring to embodiment 1, no longer repeat herein.
Then, carry out the packaging technology step of follow-up chip and pedestal, as shown in figure 17, in the through hole that is coated with metal electrode in chip, pour into resistant to elevated temperatures conductor 19, in this process, pour into conductor until be positioned at the surface of conductor and the top surface of face glass of through hole and flush.The material of this resistant to elevated temperatures conductor is preferably silver slurry in the present embodiment.
Then, chip autoregistration is poured in pedestal, and guarantee that two one metal wires 18 in pedestal are inserted into respectively two fillings and have in the through hole of conductor 19, the surface that simultaneously guarantees the base glass plate in pedestal contacts with the surface of face glass in chip, now, carry out high temperature sintering curing process, make to form a fixed connection between pedestal and chip, after technique completes, form structure as shown in figure 18.
Finally, the surface bond back side glass 12 of the second body silicon layer 3 of the chip after upside-down mounting, as shown in figure 19, because the method for making of back side glass is identical with embodiment 1, therefore no longer repeat herein.
So far, the method for making of the pressure transducer in the present embodiment finishes completely.
Due to identical with embodiment 1 of the pressure sensor structure in the present embodiment, so do not repeat at this.
Embodiment 3:
The present embodiment is different from embodiment 1 part, only comprises the part of dense boron resistive layer in the structure of formed pressure drag, and does not comprise the part of the 3rd insulation course of the side of being located thereon, and all the other processing steps are all identical with embodiment 1.
Below the pressure sensor structure in the present embodiment and method thereof are elaborated.
The pressure transducer of the present embodiment can consist of chip and pedestal.
As Figure 1-3, the processing step of the method for the present embodiment before forming Fig. 3 structure is identical with embodiment 1, can, referring to embodiment 1, no longer repeat herein.
Then, prepare the upper surface that one deck photoresist covers the 3rd insulation course 7 ', this photoresist can adopt spin coating or other processes to apply, afterwards, this photoresist is carried out to photoetching process, adopt the figuratum photomask blank of a tool to expose and developing process to this photoresist, make to form pattern in this photoresist, then the photoresistance with this pattern of take carries out etching to the 3rd insulation course 7 ' of below as mask, and making etching stopping in the upper surface of dense boron resistive layer 6 ', this etching can adopt dry etching or wet etching etc.As shown in figure 28, after over etching, the center section of the 3rd insulation course 7 ' is etched away, the part at remaining two ends, and remove remaining photoresist, subsequently, continue to adopt photoetching and etching technics at upper several pressure drags 61 that form of dense boron resistive layer 6 ', as shown in figure 29, the quantity of pressure drag 61 can need to be adjusted according to actual process, in the present embodiment, the quantity of pressure drag is 4.Because pressure drag is by carrying out forming after etching to dense boron resistive layer 6 ', therefore, the material of pressure drag is identical with the material of dense boron resistive layer.
After having formed above-mentioned pressure drag 61, carry out subsequent process steps, subsequent process steps be no matter chip front side glass, back side glass bonding or and pedestal between encapsulation, all identical with embodiment 1, finally formed pressure transducer as shown in figure 30.
So far, the method for making of the pressure transducer in the present embodiment finishes completely.
Below the structure of the pressure transducer in the present embodiment is elaborated.
As shown in figure 30, the pressure transducer in the present embodiment mainly comprises chip and pedestal, and chip is positioned at the inside of pedestal, between chip and pedestal for being fixedly connected with.
Wherein, the section of pedestal is zhou duicheng tuxing, the center line that axis of symmetry is pressure transducer.Pedestal mainly comprises that base and is connected with the glass of two one metal wires.Base is the container of a semi open model, and its top and bottom are for opening wide, and side is for sealing, to protect the chip being positioned at wherein; This base glass plate that is connected with two one metal wires comprises straight base glass plate 17 and two one metal wires 18 of partial fixing in this base glass plate 17 of an even thickness, every 18, this metal is all fixed perpendicular to this base glass plate 17, and every one metal wire 18 all runs through this base glass plate 17.
The cross-section structure of chip is zhou duicheng tuxing, the center line that axis of symmetry is pressure transducer.Chip mainly comprises face glass 9, back side glass 12 and middle layer, the lower surface bonding in the upper surface of back side glass and middle layer, the top surface bonding in the lower surface of face glass and middle layer.Wherein, the structure in middle layer is followed successively by from the bottom to top, the second body silicon layer 3, the second insulation course 4, dense boron resistive layer 6, the 3rd insulation course 7.In the second body silicon layer 3, be provided with two pressure-bearing films 31 and a mass 32, mass 32 is positioned at the centre of the second body silicon layer 3, two pressure-bearing films 31 are positioned at the both sides of this mass 32, and about these mass 32 symmetries, the section of mass 32 is inverted trapezoidal, and what the section that is positioned at the below of each pressure-bearing film 31 was hollow out is trapezoidal; Center section at dense boron resistive layer 6 and the 3rd insulation course 7 is formed with 4 pressure drags that only comprise dense boron resistance material, wherein, two left sides that are positioned at center line, two other is positioned at the right of center line; In face glass 9, be provided with a cavity 91, this cavity 91 makes to have certain distance between pressure drag 71 and face glass 9, the spacial alignment with pressure drag between cavity 91 and dense boron resistive layer 6 and the 3rd insulation course 7 forms the vacuum cavity of sealing, and the both sides in face glass 9 are also respectively provided with the through hole 92 that an inside is provided with conductor and metal electrode.The 3rd insulation course 7 at two ends is also respectively provided with a contact hole 72, and part covers sidewall, the metal electrode on bottom 8 of place, adosculation hole on the 3rd insulation course 7 and contact hole, this metal electrode 8 is double-decker, comprise the first metal layer 81 and the second metal level 82, metal electrode 8 and through hole 92 are aimed at, and the remaining space in this through hole 92 is filled up by conductor 19.
Pedestal is realized and being fixedly connected with of chip by the lower surface of its inner glass 17 and the upper surface sintering of face glass in chip 9.One end of tinsel 18 in pedestal is stretched in chip inner via hole 92, realizes being electrically connected between metal wire 18 and dense boron resistive layer 6.
Embodiment 4:
In the present embodiment, final formed device architecture is in the same manner as in Example 3, and difference is only in method for making.To being different from the step of embodiment 3 in the present embodiment, be elaborated below.
In the method for making of the present embodiment, with embodiment 3 differences be, when the preparation technology of chip carries out the structure after bonding face glass, the processing step of back side glass bonding is adjusted in the packaging technology of chip and pedestal and gone to carry out, and the final step that this step is adjusted to packaging technology is carried out, the advantage of doing is like this, the bonding of back side glass and chip in the end chip and pedestal is sintered together and just carries out afterwards, the face glass of chip now and through hole are sintered together with pedestal, therefore, before bonding, without the front covering metal layer to chip, protected overleaf, and only at last increase by the one step back side glass of technique and the bonding of chip.
After bonding face glass, carry out the packaging technology step of follow-up chip and pedestal, in the through hole that is coated with metal electrode in chip, pour into resistant to elevated temperatures conductor 19, in this process, pour into conductor until be positioned at the surface of conductor and the top surface of face glass of through hole and flush.The material of this resistant to elevated temperatures conductor is preferably silver in the present embodiment.
Then, chip autoregistration is poured in pedestal, and guarantee that two one metal wires 18 in pedestal are inserted into respectively two fillings and have in the through hole of conductor 19, the surface that simultaneously guarantees the base glass plate in pedestal contacts with the surface of face glass in chip, now, carry out high temperature sintering curing process, make to form a fixed connection between pedestal and chip.
Finally, the surface bond back side glass 12 of the second body silicon layer 3 of the chip after upside-down mounting, the structure of formation pressure transducer as shown in figure 30, because the method for making of back side glass is identical with embodiment 1, therefore no longer repeat herein.
So far, the method for making of the pressure transducer in the present embodiment finishes completely.
Due to identical with embodiment 1 of the pressure sensor structure in the present embodiment, so do not repeat at this.
For a person skilled in the art, read after above-mentioned explanation, various changes and modifications undoubtedly will be apparent.Therefore, appending claims should be regarded whole variations and the correction of containing true intention of the present invention and scope as.Within the scope of claims, scope and the content of any and all equivalences, all should think and still belong to the intent and scope of the invention.