CN102122935B - Micro-mechanical resonator having submicron clearances and manufacturing method thereof - Google Patents
Micro-mechanical resonator having submicron clearances and manufacturing method thereof Download PDFInfo
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Abstract
The invention relates to a micro-mechanical resonator having submicron clearances and a manufacturing method thereof. The micro-mechanical resonator having submicron clearances has a 'sandwich' structure which is formed by bonding following three layers of silicon wafers: a cover plate silicon wafer, a structural silicon wafer and a substrate silicon wafer, wherein the structural silicon wafer is used for manufacturing an oscillator of the resonator; the cover plate silicon wafer and the substrate silicon wafer are used for manufacturing fixed electrodes used for driving and defecting; the submicron clearances among the oscillator of the resonator and the fixed electrodes are formed by using a wafer level aligning bonding technique; and the sizes of the clearances are not limited by the photo-etching process but determined by the thickness of an insulating medium layer on the cover plate silicon wafer or the substrate silicon wafer. By using the manufacturing method of the micro-mechanical resonator, provided by the invention, the submicron clearances are formed by using the wafer level aligning bonding technique and the vacuum sealing for resonator is realized while the resonator structure is formed, thereby reducing the difficulty in designing and manufacturing the resonator, increasing the resonator performance and yield, reducing the size and the cost of the resonator.
Description
Technical field
The present invention relates to a kind of micromechanical resonator and manufacture method with sub-micron gap, belong to micromechanical resonator processing and Micrometer-Nanometer Processing Technology field.
Background technology
Clock chip, as the time base source in Circuits System, has important effect in Circuits System.Traditional clock chip generally adopts quartz crystal oscillator to produce signal waveform as resonator.But quartz crystal oscillator is generally to adopt cutting technique to make, so its volume is difficult to reduce, thereby hindered the microminiaturization of Circuits System.In addition, quartz crystal oscillator also can't with the integrated making of Circuits System, improved cost of manufacture.In recent years, due to the development of micro-processing technology, the MEMS micromechanical resonator obtains very large development.The MEMS resonator has that size is little, power consumption is little, cost is low, with CMOS IC (Complementary Metal Oxide Semiconductor Integrated Circuit, complementary mos integrated circuit) the technique advantage such as compatible mutually, demand in fields such as wireless telecommunications grows with each passing day, and will become the substitute of crystal resonator.
The key property parameter of micromechanical resonator has: resonance frequency, quality factor (Q), frequency temperature are floated etc.Wherein, the Q value of resonator is one of most important parameter of reaction resonator characteristics, and it can be expressed as:
Wherein Q is the total quality factor size of resonator, Q
airthe energy loss mechanism caused by air damping, Q
anchorthe energy loss mechanism caused by anchor point, Q
tEDthe thermoelasticity energy loss mechanism of material, Q
othersthe energy loss mechanism that means other.In these four kinds of energy loss mechanism, latter three kinds is to be caused by factors such as the material of making resonator and structural designs thereof, and the first to be vacuum degree by the resonator works environment cause.Resonator is carried out to vacuum seal, just can greatly reduce the loose consumption of energy caused due to air damping, thereby greatly improve the Q value (Khine of resonator, L and M Palaniapan, High-Q bulk-mode SOI square resonators with straight-beam anchors.Journal ofMicromechanics and Microengineering, 2009.19 (1): p.015017).
The driving of micromechanical resonator and detection principle mainly contain: electrostatic force conversion, piezoelectric effect, piezoresistive effect, thermoelectric effect etc.Condenser type drive and detection method be by electrostatic force to external world signal processed, the advantage such as low in energy consumption owing to having, structure fabrication is simple, and technique is simple, condenser type drives and detects sensing and the braking that is widely used in micro-structural.Electrostatic force in condenser type driving and detection method can be meaned by (2) formula:
Wherein F is the electrostatic force size, and ε is electric medium constant, and A is the polar plate area size, and d is spacing (C G Mattsson, K.B., the G between two-plate
h-E Nilsson and H Martin, Thermal simulation and design optimization of a thermopile infrared detector with an SU-8membrane.Journal of Micromechanics and Microengineering, 2009.19 (5): p.055016.).From (2) formula, can find out, if need to improve electrostatic force to improve the sensitivity of device, effective method is exactly the gap reduced between pole plate, because electrostatic force and pole plate gap are the relations of being inversely proportional to.
Usually the capacitance type micro mechanical resonator comprises resonance oscillator, fixedly elastic construction, drive electrode and detecting electrode four part-structures of oscillator.Traditional MEMS resonator, be all generally first to make the resonator structure, then makes the cover plate silicon chip, finally resonator is encapsulated through row, and its complex process, difficulty of processing is large.Gap between traditional resonator structure is generally by lithographic definition, if reduce gap, just needs to improve the precision of photoetching, is difficult to produce the sub-micron interstitial structure.In addition, also have and utilize oxidation polysilicon or the large gap of monocrystalline silicon thin film to make the method in sub-micron gap, but it still needs photoetching process to define a large interstitial structure, then utilize thermal oxidation technology in film interstital growth oxide layer, large gap is converted into to the sub-micron interstitial structure, this method complex manufacturing technology, cost of manufacture is high.
Summary of the invention
Problem for existing in traditional micromechanical resonator processing, the object of the invention is to propose a kind of have sub-micron gap micromechanical resonator and manufacture method.The present invention is intended to utilize simple technique and cheap cost, realizes the making in micromechanical resonator sub-micron gap and the vacuum seal of device.The present invention the most significantly is characterised in that it is to utilize the wafer level vacuum to aim at bonding to form resonator sub-micron gap, when having made resonator structure, realizes the vacuum seal to resonator.The size in sub-micron gap is determined by the thickness of the electric insulating medium layer on cover plate silicon chip or silicon substrate.
Micromechanical resonator of the present invention comprises silicon substrate, structure silicon chip, cover plate silicon chip, the resonance oscillator, the fixing elastic construction of oscillator, the electric insulating medium layer between structure silicon chip and silicon substrate and cover plate silicon chip, metal pad, electrode is drawn through hole, and basic functional principle is as shown in Figure 1.Its resonance oscillator can be circular columns or square column, can be also circular slab or square plate.The both sides, top and bottom of resonance oscillator are respectively fixed drive electrode and fixed test electrode, while applying alternating voltage like this between fixed drive electrode and resonance oscillator, the alternation electrostatic force produced by alternating voltage can encourage oscillator to enter the mode of resonance of appointment, then by detecting the variation of output electrode end output current, just resonator signal can be exported.The elastic construction that is used for fixing the resonance oscillator is elastic plate or spring beam; The elastic construction that is used for fixing the resonance oscillator is positioned in the middle of the resonance oscillator, is positioned at resonance oscillator one end or is positioned at resonance oscillator two ends.
The resonator that the present invention proposes is the sandwich structure together formed by silicon substrate, structure silicon chip and three layers of wafer bonding of cover plate silicon chip, the back side of the front of silicon substrate and structure silicon chip, the back side of the front of structure silicon chip and cover plate silicon chip is combined by the wafer level alignment keys respectively.The sub-micron gap of resonator is to aim at bonding formation by structure silicon chip and the silicon substrate with submicron order degree of depth curved cavity or cover plate silicon chip being carried out to wafer level.The structure silicon chip is between silicon substrate and cover plate silicon chip, silicon substrate front and cover plate silicon chip back side respectively have curved cavity, these two cavitys form a vacuum tightness chamber, in the vacuum tightness chamber that fixedly elastic construction of resonance oscillator forms the unsettled cavity on silicon substrate and cover plate silicon chip of resonance oscillator.
With the structure of general micromechanical resonator, compare:
The micromechanical resonator that the present invention proposes is made by wafer level vacuum aligning bonding by silicon substrate, structure silicon chip and three layers of silicon chip of cover plate silicon chip;
The silicon substrate of the micromechanical resonator that the present invention proposes and cover plate silicon chip be not only for resonator provides the vacuum tightness chamber, and also being used as is the fixed electrode of driving and detection of device simultaneously;
There is curved cavity on the silicon substrate of the micromechanical resonator that the present invention proposes and cover plate silicon chip;
There is electrode on the cover plate silicon chip of the micromechanical resonator that the present invention proposes and draw through hole.
With general micromechanical resonator manufacture method, compare:
The manufacture method of the micromechanical resonator that the present invention proposes, when having made device architecture, completed the wafer-level vacuum package of device, without the vacuum encapsulation process of follow-up complexity, reduced the complexity of design and processing, improved device performance.
The micromechanical resonator that the present invention proposes utilizes bonding technology to make the device gap, does not have the structure existed in the structure dispose procedure problems such as movable structure that easily are adhered, need protection, and has simplified processing technology, has improved rate of finished products.
The present invention utilizes wafer level to aim at bonding technology and forms the sub-micron gap, and not limited by photoetching technique, reduces difficulty, complexity and the cost of making the sub-micron gap;
The manufacture method proposed due to the present invention, when having made the resonator structure, has just been carried out wafer level vacuum seal by device, has reduced the complexity that designs and process; Adopt wafer level to aim at bonding technology and form the sub-micron gap, reduced difficulty and the complexity of making the sub-micron gap; Device has been carried out to wafer-level vacuum package, not only improved device performance, reduced cost, and be applicable to batch production.
Realize that technical scheme of the present invention is:
(1) to the structure silicon chip carry out oxidation, photoetching and graphical after, utilize deep reaction ion etching technique to make resonator oscillator the latter half structure;
(2) at the positive electric insulating medium layer that deposits one deck submicron thickness of silicon substrate, and the electric insulating medium layer is carried out to etching, form curved cavity;
(3) silicon substrate that structure silicon chip step (1) obtained obtains with step (2) carries out the wafer level vacuum and aims at bonding, forms the sub-micron gap between resonance oscillator the latter half structure and fixed electrode;
(4) the structure silicon chip that oxidation step (3) obtains, and oxide layer is carried out to photoetching and etching, utilize deep reaction ion etching technique to produce the first half structure of resonator oscillator;
(5) deposit the electric insulating medium layer of one deck submicron thickness at the cover plate silicon chip back side, and the electric insulating medium layer is carried out to etching, form curved cavity;
(6) the cover plate silicon chip that structure silicon chip step (4) obtained obtains with step (5) carries out the wafer level vacuum and aims at bonding, forms the sub-micron gap between resonance oscillator the first half structure and fixed electrode; The structure silicon chip is between silicon substrate and cover plate silicon chip;
(7) etch electrode at the cover plate front side of silicon wafer and draw through hole, erode the electric insulating medium layer that electrode is drawn the lead to the hole site place;
(8), at cover plate front side of silicon wafer and silicon substrate backside deposition metal level, and by metallic layer graphic, make metal pad.
In a word, the present invention relates to a kind of micromechanical resonator and manufacture method with sub-micron gap, it is characterized in that resonator forms " sandwich " structure by cover plate silicon chip, structure silicon chip and three layers of wafer bonding of silicon substrate.The structure silicon chip is used for making the oscillator of resonator, and cover plate silicon chip and silicon substrate are used for respectively making the fixed electrode that drives and detect.Sub-micron gap between resonator oscillator and fixed electrode is aimed at bonding technology by wafer level and is formed, and gap length is not limited by photoetching process, but determined by the thickness of the electric insulating medium layer on cover plate silicon chip or silicon substrate.Described electric insulating medium layer is silicon nitride or silica, but is not only limited to this; The scolder of the bonding between described structure silicon chip and silicon substrate, structure silicon chip and cover plate silicon chip is metal, polymer or glass paste, also is not only limited to this.The manufacture method of the micromechanical resonator that the present invention proposes, utilize wafer level to aim at bonding and form the sub-micron gap, realized the wafer level vacuum seal to device when having made device architecture, not only reduced the difficulty of device designing and making, device performance and rate of finished products have been promoted, and reduced device size, reduced cost.And can on the cover plate silicon chip, make the cmos circuit part, and then carry out the solder bonding with the structure silicon chip, realize the integrated of resonator and cmos circuit.
The accompanying drawing explanation
Fig. 1-1st, circular columns micromechanical resonator operation principle schematic diagram, (a) be resonator overall structure cutaway view, wherein (i) unsettled oscillator elastic construction is positioned at the oscillator middle part, (ii) unsettled oscillator elastic construction is positioned at position, oscillator top, and (iii) unsettled oscillator elastic construction is positioned at the oscillator two ends; (b) be the oscillator structure vertical view.
Fig. 1-2 is square plate micromechanical resonator operation principle schematic diagram, (a) is cutaway view, is (b) vertical view.
Fig. 2 is the concrete technology flow process of embodiment 1.
Fig. 2-1: the structure silicon chip after oxidation is carried out to photoetching and etching.
Fig. 2-2: utilize deep reaction ion etching technique to etch the latter half structure of resonator oscillator.
Fig. 2-3: at the electric insulating medium layer of the positive deposition of silicon substrate one deck submicron thickness, and it is graphical.
Fig. 2-4: structure silicon chip and silicon substrate are carried out to the wafer level vacuum and aim at bonding.
Fig. 2-5: thermal oxidation structure silicon chip, and its frontside oxide layer is carried out to photoetching and graphical.
Fig. 2-6: utilize deep reaction ion etching technique to etch the first half structure of resonator oscillator.
Fig. 2-7: at the electric insulating medium layer of cover plate silicon chip back side deposition one deck submicron thickness, and it is graphical.
Fig. 2-8: structure silicon chip and cover plate silicon chip are carried out to wafer level vacuum aligning bonding.
Fig. 2-9: make electrode and draw through hole on the cover plate silicon chip.
Fig. 2-10: depositing metal layers, make metal pad.
Fig. 3 is the resulting devices structure of embodiment 2.
Fig. 4 is the concrete technology flow process of embodiment 3.
Fig. 4-1: at the electric insulating medium layer of the positive deposition of silicon substrate one deck submicron thickness, and it is graphical.
Fig. 4-2: structure silicon chip and silicon substrate are carried out to wafer level aligning bonding, and the structure wafer thinning is arrived to the thickness needed.
Fig. 4-3: utilize deep reaction ion etching technique to etch the resonator oscillator structure.
Fig. 4-4: at the electric insulating medium layer of cover plate front side of silicon wafer deposition one deck submicron thickness, and it is graphical.
Fig. 4-5: structure silicon chip and cover plate silicon chip are carried out to wafer level vacuum aligning bonding.
Fig. 4-6: make electrode and draw through hole on the cover plate silicon chip.
Fig. 4-7: depositing metal layers, make metal pad.
Fig. 5 is embodiment 4 resulting devices structures.
Fig. 6 is embodiment 5 concrete technology flow processs.
Fig. 6-1: silicon substrate front etch or the solder etched;
Fig. 6-2: form curved cavity;
Fig. 6-3: the sub-micron gap formed between resonance oscillator Lower Half structure and fixed electrode;
Fig. 6-4: depositing metal layers, produce metal pad.
Fig. 7 is embodiment 6 resulting devices structures.
In figure, the implication of each digitized representation is:
1 silicon substrate; 2 structure silicon chips; 3 cover plate silicon chips; 4 electrodes are drawn through hole; 5 silica; 6 resonance oscillators; 7 unsettled oscillator structures; 11 electric insulating medium layers; 12 sub-micron gaps; 13 metal pads; 14 bonding solder layers; 15 bonding solder; The 16CMOS circuit; 21 front side of silicon wafers; 22 silicon chip back sides.
Take the resulting devices structure as reference, and structure silicon chip, silicon substrate and cover plate silicon chip one side upward are front side of silicon wafer, and one side down is silicon chip back side.As Fig. 2-10 show.
Embodiment
Below in conjunction with drawings and Examples, the present invention is described in detail.
Structure silicon chip, silicon substrate and cover plate silicon chip are all selected low resistance silicon chip, and resistivity is 0.01-1 Ω cm.The structure silicon chip is used for making the resonance oscillator structure, and the resonance oscillator is the movable electrode of resonator capacitor driving and capacitance detecting.The resonance oscillator can be circular columns, can be also square column.Fixedly the elastic construction of oscillator can be elastic plate, can be also spring beam.Silicon substrate and cover plate silicon chip are used for respectively forming the fixed electrode of resonator capacitor driving and capacitance detecting.The present embodiment adopts wafer level silicon silicon vacuum to aim at bonding, and being deposited on silicon substrate electric insulating medium layer positive and the cover plate silicon chip back side can be silica, can be also silicon nitride.Sub-micron gap length scope between fixed electrode and resonance oscillator is 0.05-2 μ m.Main technological steps comprises:
(1) oxidation structure silicon chip, carry out photoetching and etching to structure silicon chip back side silica.See Fig. 2-1.
(2) etch the latter half structure of resonator oscillator at the structure silicon chip back side.See Fig. 2-2.
(3) at the positive electric insulating medium layer that deposits one deck submicron thickness of silicon substrate, and this electric insulating medium layer is carried out to photoetching and etching formation curved cavity.See Fig. 2-3.
(4) erode the silica on the structure silicon chip that step (2) obtains, then the silicon substrate front its back side obtained with step (3) is carried out the wafer level vacuum and is aimed at bonding, forms the sub-micron gap between resonance oscillator the latter half structure and fixed electrode.See Fig. 2-4.
(5) the structure silicon chip that oxidation step (4) obtains, and its frontside oxide layer is carried out to photoetching and etching.See Fig. 2-5.
(6) etch the first half structure of resonator oscillator at the structure front side of silicon wafer.See Fig. 2-6.
(7) deposit the electric insulating medium layer of one deck submicron thickness at the cover plate silicon chip back side, and this electric insulating medium layer is carried out to photoetching and etching formation curved cavity.See Fig. 2-7.
(8) erode the oxide layer on the structure silicon chip that step (6) obtains, its positive cover plate silicon chip back side obtained with step (7) is carried out to the wafer level vacuum and aim at bonding, form the sub-micron gap between resonator oscillator the first half structure and fixed electrode.See Fig. 2-8.
(9) make electrode at the cover plate front side of silicon wafer and draw through hole, and erode the electric insulating medium layer that electrode is drawn the lead to the hole site place.See Fig. 2-9.
(10) at cover plate front side of silicon wafer and silicon substrate backside deposition metal level, and metal level is carried out graphically, make metal pad.See Fig. 2-10.
The present embodiment adopts wafer level scolder vacuum to aim at bonding, and the bonding scolder can be metal, polymer, can be also glass paste.
Its concrete implementation step part is identical with embodiment 1, the main distinction is: first, in embodiment 1 step (3) and step (7), at first deposit one deck electric insulating medium layer on silicon substrate and cover plate silicon chip, on the electric insulating medium layer, deposit or spin coating one deck solder layer again, and it is carried out to photoetching, then respectively solder layer and electric insulating medium layer are carried out to etching or corrosion; Second, in embodiment 1 step (4) and step (8), oxide layer on the corrosion structure silicon chip, deposition or spin coating one deck solder layer on the structure silicon chip, and it is carried out to photoetching and etching, the silicon chip finally obtained with step (3) in embodiment 1 and step (7) respectively carries out wafer level scolder vacuum and aims at bonding.All the other processing steps are constant.The resulting devices geometric configuration as shown in Figure 3.
The resonance oscillator can be circular slab, can be also square plate.Fixedly the structure of oscillator is spring beam.Silicon substrate and cover plate silicon chip are used for respectively forming the fixed electrode of resonator capacitor driving and capacitance detecting.Sub-micron gap length scope between fixed electrode and resonance oscillator is 0.05 μ m-2 μ m.Main technological steps comprises:
(1) at the positive electric insulating medium layer that deposits one deck submicron thickness of silicon substrate, and this electric insulating medium layer is carried out to photoetching and the graphical curved cavity that forms.See Fig. 4-1.
(2) utilize the wafer level vacuum to aim at bonding technology, the front of the silicon substrate that structure silicon chip back side and step (1) are obtained is bonded together, and, by the method attenuate structure front side of silicon wafer of physics attenuate or chemical reduction, the structure wafer thinning is arrived to needed thickness.See Fig. 4-2.
(3) carry out photoetching and graphical at the structure front side of silicon wafer, etch resonator structure.See Fig. 4-3.
(4) deposit the electric insulating medium layer of one deck submicron thickness at the cover plate silicon chip back side, and this electric insulating medium layer is carried out to photoetching and the graphical curved cavity that forms.See Fig. 4-4.
(5) utilize the wafer level vacuum to aim at bonding technology, the back side of the cover plate silicon chip that the front of the structure silicon chip that step (3) is obtained and step (4) obtain is bonded together.See Fig. 4-5.
(6) make electrode at the cover plate front side of silicon wafer and draw through hole, and erode the electric insulating medium layer that electrode is drawn the lead to the hole site place.See Fig. 4-6.
(7) at cover plate front side of silicon wafer and silicon substrate backside deposition metal level, and metal level is carried out graphically, make metal pad.See Fig. 4-7.
Its concrete implementation step part is identical with embodiment 1; the main distinction is: in embodiment 1 step (1) and step (5); before etching is made device architecture; device architecture is partly protected; then by device architecture on the structure silicon chip, outer other parts are carried out whole attenuate, make device architecture part projective structure silicon chip surface.Other processing step is constant.The resulting devices geometric configuration as shown in Figure 5.
The present embodiment adopts wafer level scolder vacuum to aim at bonding, and the bonding scolder can be metal, polymer, can be also glass paste.Can be by controlling the degree of depth of solder in the present embodiment, make scolder fill full weld material groove fully and without overflowing, thereby guarantee that the structure silicon chip surface contacts fully with silicon substrate and cover plate silicon chip surface.Silicon substrate and cover plate silicon chip are used for respectively forming the fixed electrode of resonator capacitor driving and capacitance detecting.Sub-micron gap length scope between fixed electrode and resonance oscillator is 0.05 μ m-2 μ m.Main technological steps comprises:
Main technological steps comprises:
(1) etch the latter half structure of resonator oscillator at the structure silicon chip back side.
(2) at the silicon substrate front etch or etch the bonding solder.See Fig. 6-1.
(3) at the positive electric insulating medium layer that deposits one deck submicron thickness of silicon substrate, and this electric insulating medium layer is carried out to photoetching and etching formation curved cavity.See Fig. 6-2.
(4) the silicon substrate front that structure silicon chip back side step (1) obtained obtains with step (3) is carried out wafer level scolder vacuum and is aimed at bonding, forms the sub-micron gap between resonance oscillator the latter half structure and fixed electrode.See Fig. 6-3.
(5) the structure front side of silicon wafer obtained in step (4) etches the first half structure of resonator oscillator.
(6) corrosion or etch the bonding solder on the cover plate silicon chip back side.
(7) deposit the electric insulating medium layer of one deck submicron thickness at the cover plate silicon chip back side, and this electric insulating medium layer is carried out to photoetching and etching formation curved cavity.
(8) the cover plate silicon chip back side that structure front side of silicon wafer step (5) obtained obtains with step (7) carries out wafer level scolder vacuum and aims at bonding, forms the sub-micron gap between resonator oscillator the first half structure and fixed electrode.
(9) make electrode at the cover plate front side of silicon wafer and draw through hole, and erode the electric insulating medium layer that electrode is drawn the lead to the hole site place.
(10) at cover plate front side of silicon wafer and silicon substrate backside deposition metal level, and metal level is carried out graphically, make metal pad.See Fig. 6-4.
The present embodiment adopts wafer-level low-temperature scolder bonding, and the bonding scolder can be metal, polymer, can be also glass paste.
Its concrete implementation step part is identical with embodiment 5, the main distinction is: first, in embodiment 5 steps (8), before vacuum is aimed at bonding, first by CMOS technique, on the cover plate silicon chip, produce cmos circuit, and then utilize the solder bonding technology that itself and structure silicon chip are carried out to wafer-level low-temperature scolder bonding.The second, in embodiment 5 steps (10), after making metal pad, utilize routing technique to realize the pin interconnection of resonator and cmos circuit.Other processing step is constant.The resulting devices geometric configuration as shown in Figure 7.
Can find out that by the introduction of above-described embodiment the method in the sub-micron gap that the present invention mentions has following several:
1) deposit respectively the electric insulating medium layer of one deck submicron thickness on silicon substrate front and cover plate silicon chip back side, the electric insulating medium layer that etches away respectively resonance oscillator corresponding position forms curved cavity, then silicon substrate, cover plate silicon chip is carried out to wafer level with the structure silicon chip respectively and aims at the sub-micron gap between bonding formation resonance oscillator and fixed electrode.The sub-micron gap length is exactly the power on thickness of insulating medium layer of silicon substrate or cover plate silicon chip;
2) deposit respectively electric insulating medium layer and the solder layer of one deck submicron thickness on silicon substrate front and cover plate silicon chip back side, the insulating medium layer and the solder layer that erode respectively resonance oscillator corresponding position form curved cavity, then, silicon substrate, cover plate silicon chip are carried out to the wafer level scolder with the structure silicon chip respectively and aim at the sub-micron gap between bonding formation resonance oscillator and fixed electrode; Total the thickness of insulating medium layer and solder layer be exactly the size silicon substrate in sub-micron gap or cover plate silicon chip power on.
3) deposit respectively one deck electric insulating medium layer on silicon substrate front and cover plate silicon chip back side, the electric insulating medium layer that etches away respectively resonance oscillator corresponding position forms curved cavity.After part outside structure silicon chip resonance oscillator structure is carried out to the double-sided overall attenuate, silicon substrate, cover plate silicon chip are carried out to wafer level with the structure silicon chip respectively and aim at bonding formation sub-micron gap.The size in sub-micron gap is exactly that the power on thickness of insulating medium layer of silicon substrate or cover plate silicon chip deducts the difference of resonance oscillator projective structure silicon chip level.
4) deposit respectively the electric insulating medium layer of one deck submicron thickness on silicon substrate front and cover plate silicon chip back side, the electric insulating medium layer that etches away respectively resonance oscillator corresponding position forms curved cavity.Then and cover plate silicon chip back side positive at silicon substrate etches for applying the groove of bonding scolder, then silicon substrate, cover plate silicon chip carried out to the wafer level scolder with the structure silicon chip respectively and aims at bonding formation sub-micron gap.The bonding scolder should fill solder fully and nothing is overflowed.The size in sub-micron gap is exactly the power on thickness of insulating medium layer of silicon substrate or cover plate silicon chip.
Claims (10)
1. the micromechanical resonator manufacture method with sub-micron gap, it is characterized in that utilizing wafer level to aim at bonding and form the sub-micron gap, when having made the resonator structure, realized the wafer-level vacuum package to device, the concrete technology step is:
1) to the structure silicon chip carry out oxidation, photoetching and graphical after, utilize deep reaction ion etching technique to make resonance oscillator the latter half structure;
2) at the positive electric insulating medium layer that deposits one deck submicron thickness of silicon substrate, and the electric insulating medium layer is carried out to etching, form curved cavity;
3) silicon substrate that structure silicon chip step (1) obtained obtains with step (2) carries out the wafer level vacuum and aims at bonding, forms the sub-micron gap between resonance oscillator the latter half structure and fixed electrode;
4) the structure silicon chip that oxidation step (3) obtains, and oxide layer is carried out to photoetching and etching, utilize deep reaction ion etching technique to produce the first half structure of resonance oscillator;
5) deposit the electric insulating medium layer of one deck submicron thickness at the cover plate silicon chip back side, and the electric insulating medium layer is carried out to etching, form curved cavity;
6) the cover plate silicon chip that structure silicon chip step (4) obtained obtains with step (5) carries out the wafer level vacuum and aims at bonding, forms the sub-micron gap between resonance oscillator the first half structure and fixed electrode; The structure silicon chip is between silicon substrate and cover plate silicon chip;
7) etch electrode at the cover plate front side of silicon wafer and draw through hole, erode the electric insulating medium layer that electrode is drawn the lead to the hole site place;
8), at cover plate front side of silicon wafer and silicon substrate backside deposition metal level, and by metallic layer graphic, make metal pad;
When having made the resonator structure, realized the wafer-level vacuum package to device.
2. method according to claim 1, the method that it is characterized in that making the sub-micron gap has one of following four kinds:
1) deposit respectively the electric insulating medium layer of one deck submicron thickness on silicon substrate front and cover plate silicon chip back side, the electric insulating medium layer that etches away respectively resonance oscillator corresponding position forms curved cavity, then silicon substrate, cover plate silicon chip is carried out to wafer level with the structure silicon chip respectively and aims at the sub-micron gap between bonding formation resonance oscillator and fixed electrode; The sub-micron gap length is exactly the power on thickness of insulating medium layer of silicon substrate or cover plate silicon chip;
2) deposit respectively electric insulating medium layer and the solder layer of one deck submicron thickness on silicon substrate front and cover plate silicon chip back side, the insulating medium layer and the solder layer that erode respectively resonance oscillator corresponding position form curved cavity, then, silicon substrate, cover plate silicon chip are carried out to the wafer level scolder with the structure silicon chip respectively and aim at the sub-micron gap between bonding formation resonance oscillator and fixed electrode; Total the thickness of insulating medium layer and solder layer be exactly the size silicon substrate in sub-micron gap or cover plate silicon chip power on;
3) deposit respectively one deck electric insulating medium layer on silicon substrate front and cover plate silicon chip back side, the electric insulating medium layer that etches away respectively resonance oscillator corresponding position forms curved cavity; After part outside structure silicon chip resonance oscillator structure is carried out to the double-sided overall attenuate, silicon substrate, cover plate silicon chip are carried out to wafer level with the structure silicon chip respectively and aim at bonding formation sub-micron gap; The size in sub-micron gap is exactly that the power on thickness of insulating medium layer of silicon substrate or cover plate silicon chip deducts the difference of resonance oscillator projective structure silicon chip level;
4) deposit respectively the electric insulating medium layer of one deck submicron thickness on silicon substrate front and cover plate silicon chip back side, the electric insulating medium layer that etches away respectively resonance oscillator corresponding position forms curved cavity; Then and cover plate silicon chip back side positive at silicon substrate etches for applying the groove of bonding scolder, then silicon substrate, cover plate silicon chip are carried out to the wafer level scolder with the structure silicon chip respectively and aim at bonding formation sub-micron gap, the bonding scolder should fill solder fully and nothing is overflowed; The size in sub-micron gap is exactly the power on thickness of insulating medium layer of silicon substrate or cover plate silicon chip.
3. the micromechanical resonator with sub-micron gap of being made by method claimed in claim 1, it is characterized in that described resonator comprises silicon substrate, the structure silicon chip, the cover plate silicon chip, resonance oscillator, the fixedly elastic construction of oscillator, electric insulating medium layer between structure silicon chip and silicon substrate and cover plate silicon chip, metal pad, electrode is drawn through hole, wherein:
1) resonator is by silicon substrate, structure silicon chip and three layers of sandwich structure that is bonded together and forms of cover plate silicon chip, the back side of the front of silicon substrate and structure silicon chip, the back side of the front of structure silicon chip and cover plate silicon chip is combined by wafer level vacuum alignment keys respectively;
2) silicon substrate front and cover plate silicon chip back side have curved cavity; The cavity of the cavity in silicon substrate front and cover plate silicon chip back side forms a vacuum tightness chamber;
3) the structure silicon chip is used for making the oscillator of resonator, and cover plate silicon chip and silicon substrate are used for respectively making the fixed electrode that drives and detect, and the sub-micron gap between resonance oscillator and fixed electrode is to form by the wafer level bonding technology;
4) fixedly the elastic construction of resonance oscillator by the resonance oscillator in the fixing and unsettled vacuum tightness chamber being formed by cover plate silicon chip and silicon substrate;
5) electrode is drawn through hole and is positioned on resonator cover plate silicon chip.
4. resonator according to claim 3 is characterized in that:
1) described resonance oscillator is circular columns, square column, circular slab, or the square plate structure;
2) elastic construction that is used for fixing the resonance oscillator is elastic plate or spring beam;
3) elastic construction that is used for fixing the resonance oscillator is positioned in the middle of the resonance oscillator, is positioned at resonance oscillator one end or is positioned at resonance oscillator two ends.
5. according to the described resonator of claim 3 or 4, it is characterized in that the both sides up and down of resonance oscillator are respectively the driving fixed electrode and detect fixed electrode.
6. resonator according to claim 3, is characterized in that silicon substrate, structure silicon chip and the cover plate silicon chip of described sandwich structure consisting selected the low resistance silicon chip that resistivity is 0.01～1 Ω CM.
7. resonator according to claim 3, is characterized in that the sub-micron gap between described fixed electrode and resonance oscillator is 0.05～2 μ m.
8. according to the described resonator of claim 3 or 7, it is characterized in that described gap length is the electric insulating medium layer thickness decision on cover plate silicon chip or silicon substrate.
9. resonator according to claim 3, is characterized in that the electric insulating medium layer between structure silicon chip and silicon substrate, structure silicon chip and cover plate silicon chip is silica or silicon nitride.
10. resonator according to claim 3, the scolder that it is characterized in that the bonding between structure silicon chip and silicon substrate, structure silicon chip and cover plate silicon chip is metal, polymer or glass paste.
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| CN103204456B (en) * | 2012-01-16 | 2016-05-18 | 台湾积体电路制造股份有限公司 | Be used for the supporting construction of the TSV of MEMS structure |
| CN102862947B (en) * | 2012-09-18 | 2016-01-27 | 华东光电集成器件研究所 | A kind of MEMS and wafer-level vacuum encapsulating method thereof |
| CN103281048B (en) * | 2013-06-14 | 2016-04-20 | 中国科学院半导体研究所 | A kind of micromechanical resonator and preparation method thereof |
| CN105258713B (en) * | 2015-11-17 | 2017-06-16 | 哈尔滨工业大学 | A kind of quartz crystal oscillator sensor of use low temperature glass solder welding and preparation method thereof |
| US10797681B1 (en) * | 2019-07-25 | 2020-10-06 | Zhuhai Crystal Resonance Technologies Co., Ltd. | Method of fabricating novel packages for electronic components |
| CN111551161A (en) * | 2020-06-28 | 2020-08-18 | 江苏睦荷科技有限公司 | MEMS vibrating gyroscope structure and manufacturing method thereof |
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