CN204085748U - Piezoresistive pressure sensor - Google Patents
Piezoresistive pressure sensor Download PDFInfo
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- CN204085748U CN204085748U CN201420580179.8U CN201420580179U CN204085748U CN 204085748 U CN204085748 U CN 204085748U CN 201420580179 U CN201420580179 U CN 201420580179U CN 204085748 U CN204085748 U CN 204085748U
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Abstract
The utility model provides a kind of piezoresistive pressure sensor, it vacuum cavity comprising substrate, be bonded in the ground floor wafer in substrate front and be formed between ground floor wafer and substrate.Described substrate has substrate, is arranged on the first insulation course of substrate face and is arranged on the movable sensitive rete between the first insulation course front and ground floor wafer.Described substrate is formed with the back of the body chamber exposed at the movable sensitive rete back side downwards.
Description
Technical field
The utility model is positioned at technical field of microelectronic mechanical systems, particularly relates to a kind of piezoresistive pressure sensor.
Background technology
Pressure transducer is one of product occurring the earliest in MEMS sensor and apply, and pressure resistance type, condenser type and piezoelectric type etc. can be divided into several according to principle of work.Wherein, piezoresistive pressure sensor has the advantages such as output signal is large, the simple and applicable production in enormous quantities of subsequent treatment.Sensitivity is a critical performance parameters of pressure transducer, and the homogeneity of monocrystalline silicon piezoresistance film thickness and consistance decide the consistance of Sensitivity in Pressure Sensors.
At present, the job operation of the monocrystalline silicon piezoresistance film of pressure drag type pressure sensing has two kinds: a kind of is utilize alkaline solution to carry out anisotropic etch from the back side of silicon chip, thus forms monocrystalline silicon pressure-sensitive film in front while the back side of silicon chip forms back of the body chamber.This mode adopts the control corrosion rate time to control the thickness of pressure drag film, can not ensure the homogeneity of pressure drag film thickness in sheet and between sheet and consistance; The another kind of comparatively normal method adopted is galvanic corrosion; the method can obtain the light dope pressure-sensitive film that can make pressure drag thereon; but this kind of method need add potentiostat costly; and adopt the fixture of particular design to protect front be not corroded and apply the front of voltage to silicon chip; such one side improves equipment cost; too increase the complexity of technique on the other hand, make production efficiency very low.
Existing piezoresistive pressure sensor major part all adopts frontal inlet, and pressure drag film directly contacts with external environment, pressure drag film surface vulnerable to pollution, and reliability is bad; Although can instilling gel at chip surface, to carry out protect IC not contaminated, gel price, considerably increases sensor cost.
The another kind of method for making of piezoresistive pressure sensor is at the back side of pressure transducer or front bonding glass, but silex glass bonding temperature is high, can affect charge carrier and distribute, affect sensor performance; And it is enough large that silex glass bonding reserves area, prevents the existence of particle from affecting bonding quality, and make chip size large.
Therefore, be necessary to be improved to solve the problem to existing pressure transducer.
Utility model content
The purpose of this utility model is to provide a kind of convenient making and sensitivity and the good piezoresistive pressure sensor of consistance.
For realizing above-mentioned utility model object, the utility model provides a kind of piezoresistive pressure sensor, the vacuum cavity that described pressure transducer comprises substrate, is bonded in the ground floor wafer in substrate front and is formed between ground floor wafer and substrate, described substrate has substrate, is arranged on the first insulation course of substrate face and is arranged on the movable sensitive rete between the first insulation course front and ground floor wafer, and described substrate is formed with the back of the body chamber exposed at the movable sensitive rete back side downwards.
As further improvement of the utility model, Al-Ge bonding is adopted between described substrate and ground floor wafer, wherein said ground floor wafer has and is formed in towards the twin islet of substrate side and the Ge metal connecting layer being arranged on twin islet surface, described substrate has the Al metal docking section with Ge metal connecting layer bonding, and described vacuum cavity is formed between twin islet and substrate.
As further improvement of the utility model, described movable sensitive rete front is provided with doped region, described substrate also has the insulation composite being arranged on movable sensitive rete front and the pressure welding point running through insulation composite and connecting doped area territory, and described Al metal docking section is arranged on described insulation composite front and is positioned at above doped region.
As further improvement of the utility model, described insulation composite comprises the silicon oxide layer being deposited on movable sensitive rete front, the silicon nitride layer being deposited on silicon oxide layer front and is deposited on the another silicon oxide layer in silicon nitride layer front, or also can be and only comprise the silicon oxide layer being deposited on movable sensitive rete front and the silicon nitride layer being deposited on silicon oxide layer front.
As further improvement of the utility model, described doped region comprises lightly doped region and heavily doped region; Described lightly doped region is positioned at directly over back of the body chamber, and described heavily doped region is positioned at outside back of the body chamber; Described pressure welding point by arranging through hole and be connected with part heavily doped region on insulation composite, described Al metal docking site directly over heavily doped region, and and pressure welding point interval arrange.
As further improvement of the utility model, the big up and small down type in described back of the body chamber is arranged.
The beneficial effects of the utility model are: the thickness being formed directly into the movable sensitive rete on the first insulation course in the utility model pressure transducer directly defines the thickness of pressure transducer, conveniently the thickness of movable sensitive rete is controlled, and sensitivity and the consistance of movable sensitive rete can be ensured; And adopt Al-Ge bonding between substrate and ground floor wafer, bonding quality is good; In addition, vacuum cavity is arranged on movable sensitive rete front, back of the body chamber is arranged on the back side and adopts back side air inlet, and movable sensitive film surface can be protected not contaminated.Generally speaking, based on the utility model pressure transducer, have that bonding quality is good, back side air inlet reliability is high, conveniently control the advantages such as thickness, sensitivity and consistance are good.
Accompanying drawing explanation
Fig. 1 to Fig. 7 A and Fig. 8 to Figure 12 is the manufacturing process schematic diagram of the utility model piezoresistive pressure sensor.
Fig. 7 B is the vertical view schematic diagram of Fig. 7 A.
Embodiment
Below with reference to each embodiment shown in the drawings, the utility model is described in detail.But these embodiments do not limit the utility model, the structure that those of ordinary skill in the art makes according to these embodiments, method or conversion functionally are all included in protection domain of the present utility model.
Please refer to the preferred embodiment that Figure 12 shows that the utility model piezoresistive pressure sensor.Described pressure transducer comprises substrate, is bonded in the ground floor wafer 9 in substrate front and is formed in the vacuum cavity 93 between ground floor wafer 9 and substrate.Al-Ge bonding is adopted between described substrate and ground floor wafer 9, wherein said ground floor wafer 9 has and is formed in towards the twin islet 91 of substrate side and the Ge metal connecting layer 92 being arranged on twin islet 91 surface, described substrate has the Al metal docking section 72 with Ge metal connecting layer 92 bonding, and described vacuum cavity 93 is formed between twin islet 91 and substrate.
Described substrate has substrate 1, be arranged on first insulation course 3 in substrate 1 front, be arranged on movable sensitive rete 4 between the first insulation course 3 front and ground floor wafer 9.Described substrate 1 is formed with the back of the body chamber 10 exposed at movable sensitive rete 4 back side downwards, carries on the back chamber 10 and be formed as up big and down small type described in the present embodiment.
Described movable sensitive rete 4 front is provided with doped region 5.Described substrate also has the insulation composite 6 being arranged on movable sensitive rete 4 front and the pressure welding point 71 running through insulation composite 6 and connecting doped area territory 5.Described Al metal docking section 72 is arranged on described insulation composite 6 front and is positioned at above doped region 5.Described ground floor wafer 9 is bonded in described insulation composite 6 front, thus described vacuum cavity 93 is specifically formed between twin islet 91 and insulation composite 6.
Described doped region 5 comprises the lightly doped region 51 being formed as pressure drag bar and the heavily doped region 52 being formed as wire.Described lightly doped region 51 is positioned at directly over back of the body chamber 10, and described heavily doped region 52 is positioned at outside back of the body chamber 10; Described pressure welding point 71 by arranging through hole and being connected with part heavily doped region 52 on insulation composite 6, and described Al metal docking section 72 is positioned at directly over heavily doped region 52, and and pressure welding point 71 interval arrange.
Described insulation composite 6 comprises the silicon oxide layer 61 being deposited on movable sensitive rete 4 front, the silicon nitride layer 62 being deposited on silicon oxide layer 61 front and is deposited on the another silicon oxide layer 61 in silicon nitride layer 62 front, or also can be and only comprise the silicon oxide layer 61 being deposited on movable sensitive rete 4 front and the silicon nitride layer 62 being deposited on silicon oxide layer 61 front.
Fig. 1 to Figure 12 is the method for making process flow diagram of the above-mentioned piezoresistive pressure sensor of the utility model.This method for making comprises the steps S1 to S10.
S1: please refer to shown in Fig. 1, provides substrate 1; Described substrate 1 is certain thickness low-resistivity silicon, plays a supportive role.Shown in composition graphs 2, in the present embodiment, also being included in substrate 1 front in this step adopts photoetching or plasma etch process to form square cavity 2, thus etching depth when regulating follow-up back of the body chamber 10 shaping by this cavity 2, and adjustable shaping after pressure transducer on the shape in back of the body chamber 10 or size, and then the product of multiple range can be realized; Certain cavity 2 also can be set to other circles or irregularly shaped according to relevant range demand, the equally also object of attainable cost utility model; Certainly, if back of the body chamber 10 can in the end shaping time be directly formed to preset shape or size, also can this cavity 2 shaping in this step.
S2: please refer to shown in Fig. 3, is oxidized or the deposit of LPCVD(low temperature chemical vapor respectively to the front and back of substrate 1), form the first insulation course 3.This first insulation course 3 can be monox.Above-mentioned first insulation course 3 covers the inside surface of cavity 2.
S3: incorporated by reference to Fig. 4, bonding one silicon layer 4 on first insulation course 3 in substrate 1 front, this silicon layer 4 is formed as movable sensitive rete 4, and this movable sensitive rete 4 defines the sensitivity of pressure transducer.
Wherein: the silicon layer 4 in this S3 step is specifically formed by such as under type one or mode two:
Mode one: first bonding one silicon chip on first insulation course 3 in substrate 1 front, then adopts CMP (Chemical Mechanical Polishing) process thinning this silicon chip and forms described silicon layer 4;
Mode two: the SOI(silicon-on-insulator being first inverted a routine on first insulation course 3 in substrate 1 front) wafer (not shown), the silicon layer of this SOI wafer first insulation course 3 that reclines is arranged, then remove substrate layer and the insulation course of SOI wafer, make the described silicon layer 4 that the silicon layer of this SOI wafer is formed as in S3 step.
Thus, the pressure drag film thickness of the utility model pressure transducer, by can directly be determined by the thickness of silicon layer 4, facilitates shaping and is convenient to control forming process, greatly can improve sensitivity and the consistance of the utility model pressure transducer simultaneously.
S4: incorporated by reference to Fig. 5, forms doped region 5 in movable sensitive rete 4 front, comprises lightly doped region 51 and heavily doped region 52; Be specially: on movable sensitive rete 4, adopt lithography corrosion process to form heavily doped region, and adopt ion implantation technology to carry out heavy doping, thus form the heavily doped region 52 used as wire; And then adopt lithography corrosion process to form light doping section, and adopt ion implantation technology to carry out light dope, form the lightly doped region 51 as pressure drag bar.
S5: incorporated by reference to Fig. 6, forms insulation composite 6 in the deposit of movable sensitive rete 4 front; This insulation composite 6 comprises the silicon oxide layer 61 being deposited on movable sensitive rete 4 front, the silicon nitride layer 62 being deposited on silicon oxide layer 61 front and is deposited on the another silicon oxide layer 61 in silicon nitride layer 62 front, or also can be and only comprise the silicon oxide layer 61 being deposited on movable sensitive rete 4 front and the silicon nitride layer 62 being deposited on silicon oxide layer 61 front.This insulation composite 6 with certain thickness ratio deposit, to reach stress equilibrium state.
S6: incorporated by reference to Fig. 7 A and Fig. 7 B, insulation composite 6 is formed the through hole be communicated with part doped region 5, and the insulation composite 6 surface deposition metal in through hole and above doped region 5, thus form the pressure welding point 71 contacted with doped region 5 and the Al metal docking section 72 being positioned at insulation composite 6 surface; Wherein said through hole adopts photoetching corrosion or anisotropic etching to be formed, and described pressure welding point 71 is specially and contacts with heavily doped region 52, for extraction signal; Al metal docking section 72 is distributed in directly over heavily doped region 52, and is mainly used as bonding; Composition graphs 7B, described pressure welding point 71 and Al metal docking section 72 material are all metal A l, and pressure welding point 71 quantity has 4, and is distributed in side; Al metal docking section 72 continuous distribution is in surrounding.
S7: incorporated by reference to Fig. 8, adopts lithographic etch process on first insulation course 3 at substrate 1 back side, etch the window 8 in back of the body chamber 10.
S8: composition graphs 9, provides ground floor wafer 9, and this ground floor wafer 9 through etching twin islet 91, form Ge metal connecting layer 92 at this twin islet 91 surface sputtering simultaneously on another substrate; And ground floor wafer 9, by Ge metal connecting layer 92 and Al metal docking section 72, low temperature eutectic bonding is occurred and forms as one, wherein form vacuum cavity 93 between twin islet 91 and insulation composite 6; For the utility model pressure transducer after avoiding bonding is too high, the suitable reduction processing of CMP (Chemical Mechanical Polishing) process can be carried out to another substrate above-mentioned.
S9: in conjunction with Figure 10, Figure 11, using the first insulation course 3 as mask plate, the substrate 1 above window 8 is etched, stop until etching into the first insulation course 3, thus form back of the body chamber 10, then the first insulation course 3 be exposed in back of the body chamber 10 is removed, make movable sensitive rete 4 back side and atmosphere, wherein, above-mentioned have back of the body substrate 1, first insulation course 3 in chamber 10, movable sensitive rete 4 and insulation composite 6 and form substrate.
S10, in conjunction with Figure 12, cut to expose pressure welding point 71 to the edge of ground floor wafer 9, be convenient to routing and draw signal.
Wherein, in above-mentioned steps: described window 8 is formed between the lateral border of square cavity 2, thus make the big up and small down type in back of the body chamber 10 that formed in S9.
In sum, the thickness being formed directly into the movable sensitive rete 4 on the first insulation course 3 in the utility model pressure transducer directly defines the thickness of pressure transducer, conveniently the thickness of movable sensitive rete 4 is controlled, and sensitivity and the consistance of movable sensitive rete 4 can be ensured; And adopt Al-Ge bonding between substrate and ground floor wafer 9, bonding quality is good; In addition, vacuum cavity 93 is arranged on movable sensitive rete 4 front, back of the body chamber 10 is arranged on the back side and adopts back side air inlet, and movable sensitive rete 4 surface can be protected not contaminated.Generally speaking, based on the utility model pressure transducer that said method is made, have that bonding quality is good, back side air inlet reliability is high, conveniently control the advantages such as thickness, sensitivity and consistance are good.
Be to be understood that, although this instructions is described according to embodiment, but not each embodiment only comprises an independently technical scheme, this narrating mode of instructions is only for clarity sake, those skilled in the art should by instructions integrally, technical scheme in each embodiment also through appropriately combined, can form other embodiments that it will be appreciated by those skilled in the art that.
A series of detailed description listed is above only illustrating for feasibility embodiment of the present utility model; they are also not used to limit protection domain of the present utility model, all do not depart from the utility model skill equivalent implementations of doing of spirit or change all should be included within protection domain of the present utility model.
Claims (6)
1. a piezoresistive pressure sensor, it is characterized in that, the vacuum cavity that described pressure transducer comprises substrate, is bonded in the ground floor wafer in substrate front and is formed between ground floor wafer and substrate, described substrate has substrate, is arranged on the first insulation course of substrate face and is arranged on the movable sensitive rete between the first insulation course front and ground floor wafer, and described substrate is formed with the back of the body chamber exposed at the movable sensitive rete back side downwards.
2. piezoresistive pressure sensor according to claim 1, it is characterized in that, Al-Ge bonding is adopted between described substrate and ground floor wafer, wherein said ground floor wafer has and is formed in towards the twin islet of substrate side and the Ge metal connecting layer being arranged on twin islet surface, described substrate has the Al metal docking section with Ge metal connecting layer bonding, and described vacuum cavity is formed between twin islet and substrate.
3. piezoresistive pressure sensor according to claim 2, it is characterized in that, described movable sensitive rete front is provided with doped region, described substrate also has the insulation composite being arranged on movable sensitive rete front and the pressure welding point running through insulation composite and connecting doped area territory, and described Al metal docking section is arranged on described insulation composite front and is positioned at above doped region.
4. piezoresistive pressure sensor according to claim 3, it is characterized in that, described insulation composite comprises the silicon oxide layer being deposited on movable sensitive rete front, the silicon nitride layer being deposited on silicon oxide layer front and is deposited on the another silicon oxide layer in silicon nitride layer front, or also can be and only comprise the silicon oxide layer being deposited on movable sensitive rete front and the silicon nitride layer being deposited on silicon oxide layer front.
5. piezoresistive pressure sensor according to claim 3, is characterized in that, described doped region comprises lightly doped region and heavily doped region; Described lightly doped region is positioned at directly over back of the body chamber, and described heavily doped region is positioned at outside back of the body chamber; Described pressure welding point by arranging through hole and be connected with part heavily doped region on insulation composite, described Al metal docking site directly over heavily doped region, and and pressure welding point interval arrange.
6. piezoresistive pressure sensor according to claim 1, is characterized in that, the big up and small down type in described back of the body chamber is arranged.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420580179.8U CN204085748U (en) | 2014-10-09 | 2014-10-09 | Piezoresistive pressure sensor |
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| CN201420580179.8U CN204085748U (en) | 2014-10-09 | 2014-10-09 | Piezoresistive pressure sensor |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104266781A (en) * | 2014-10-09 | 2015-01-07 | 苏州敏芯微电子技术有限公司 | Piezoresistive pressure sensor and manufacturing method thereof |
| CN104900714A (en) * | 2015-05-29 | 2015-09-09 | 歌尔声学股份有限公司 | Pressure sensor manufacturing method and pressure sensor |
| CN106257254A (en) * | 2015-06-22 | 2016-12-28 | 意法半导体股份有限公司 | Generate pressure transducer and the manufacture method thereof of the ambient temperature dependent transducing signal with reduction |
| TWI700241B (en) * | 2019-12-27 | 2020-08-01 | 新唐科技股份有限公司 | Sensor membrane structure and method for forming the same |
-
2014
- 2014-10-09 CN CN201420580179.8U patent/CN204085748U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104266781A (en) * | 2014-10-09 | 2015-01-07 | 苏州敏芯微电子技术有限公司 | Piezoresistive pressure sensor and manufacturing method thereof |
| CN104900714A (en) * | 2015-05-29 | 2015-09-09 | 歌尔声学股份有限公司 | Pressure sensor manufacturing method and pressure sensor |
| CN104900714B (en) * | 2015-05-29 | 2018-08-03 | 歌尔股份有限公司 | A kind of manufacturing method and pressure sensor of pressure sensor |
| CN106257254A (en) * | 2015-06-22 | 2016-12-28 | 意法半导体股份有限公司 | Generate pressure transducer and the manufacture method thereof of the ambient temperature dependent transducing signal with reduction |
| US10809140B2 (en) | 2015-06-22 | 2020-10-20 | Stmicroelectronics S.R.L. | Pressure sensor generating a transduced signal with reduced ambient temperature dependence, and manufacturing method thereof |
| TWI700241B (en) * | 2019-12-27 | 2020-08-01 | 新唐科技股份有限公司 | Sensor membrane structure and method for forming the same |
| US11561145B2 (en) | 2019-12-27 | 2023-01-24 | Nuvoton Technology Corporation | Sensor membrane structure with insulating layer |
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Address after: 215123, NW-09 building, room 99, Jinji Lake Avenue, Suzhou Industrial Park, Jiangsu, 102 Patentee after: MEMSENSING MICROSYSTEMS (SUZHOU, CHINA) CO., LTD. Address before: 99 building NW-09 No. 215123 in Jiangsu Province, Suzhou City Industrial Park Jinji Lake Avenue, Room 501 Patentee before: Suzhou MEMSensing Microsystems Co., Ltd. |