CN1373367A - Miniature silicon dridge type heat convection acceleration sensor - Google Patents
Miniature silicon dridge type heat convection acceleration sensor Download PDFInfo
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- CN1373367A CN1373367A CN 02116842 CN02116842A CN1373367A CN 1373367 A CN1373367 A CN 1373367A CN 02116842 CN02116842 CN 02116842 CN 02116842 A CN02116842 A CN 02116842A CN 1373367 A CN1373367 A CN 1373367A
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Abstract
A miniature silicon bridge type acceleration sensor based on heat convection principle is composed of a sealed cavity, a heating wire in the center of said cavity, two pairs of temp sensors symmetric about said heating wire and bridge-type temp measuring circuit composed of said temp sensors. Its advantages are high range and impact resistance, small size, low cost, and high linearity, sensitivity and response frequency.
Description
Technical field
The invention belongs to sensor technical field, particularly be suitable for the micro-machined thermal convection arrangements of accelerometers design of silicon.
Background technology
Acceleration transducer all has broad application prospects in communications and transportation (automobile, aircraft, boats and ships), the product for civilian use (camera, toy, mouse), Industry Control and robot and military affairs fields such as (guided missile, precision guided weapon, satellites).Development size novel accelerometer littler, that performance better, reliability is higher, price is lower is the target that people are pursuing always.The present acceleration transducer of using, its popular feature is to need the quality inspection piece.The existence of mass makes that narrow, the shock-resistant ability of the measurement range of sensor is weak, reliability is low, makes that also physical dimension is big, cost is higher.In addition, also there is such or such problem in the mass detection of motion, apparent in view such as piezoelectricity or piezoresistive accelerometer temperature influence, and condenser type is subjected to initial effect of parasitic capacitance bigger.
The problems referred to above impel people to seek acceleration transducer without mass.1996, United States Patent (USP) 5581034 proposed a kind of with the acceleration transducer of fluid as actuating medium, and adopted conventional machining process to give realization, and its synoptic diagram as shown in Figure 1.1,5 is earth connection point among the figure, and 9,12 is temperature sensor, and 2,4,6,8 is the temperature sensor joint, and 11 is heater strip, and 3,7 is the joint of heater strip, and 10 is airtight container, and 13 is the acceleration direction.Its principle of work is: when heater strip 11 galvanizations heated, its temperature raise, and near the also corresponding rising of temperature of the fluid around it, thereby formed natural convection in seal chamber.When not having acceleration to act on this device, gas flow and heat transfer are that rotational symmetry is distributed in both sides with the heater strip, the temperature sensor 9 of two symmetric arrangement, 12 detect identical temperature, and when acceleration 13 acts on this device, mobile and heat exchange in the cavity will no longer be symmetrically distributed, and two temperature sensors 9,12 will detect different temperature, and the temperature difference ratio between them is in the size of acceleration.Acceleration is big more, and the asymmetry of the free convection in the cavity is strong more, and the temperature difference is also just big more.Just can obtain the size of acceleration by the detected temperatures difference.Above-mentioned accelerometer has overcome the problem that adopts mass to bring in the general accelerometer owing to adopt gas as actuating medium, has more advantage.The weak point of this acceleration transducer is: 1) physical dimension is big, response frequency is low; 2) poor sensitivity; 3) output signal is non-linear.
Summary of the invention
The objective of the invention is to use above-mentioned thermal convection principle, propose a kind of miniature silicon dridge type thermal convection acceleration transducer, its structural parameters and actuating medium have been carried out choosing of optimization for overcoming the weak point of prior art.The present invention is suitable for the little processing of silicon, has characteristics such as volume is little, cost is low, performance is good.
The present invention proposes a kind of miniature silicon dridge type thermal convection acceleration transducer, it is characterized in that, comprise a seal chamber, a heater strip in this cavity center, be symmetrically placed in two pairs of temperature sensors of these heater strip both sides, and the bridge-type temperature sensing circuit that constitutes by these two pairs of temperature sensors.
First pair of sensor near said heater strip can be positioned at apart from heater strip 0.2-0.3 doubly to the position of cavity half length, second pair of sensor can be apart from the position of first couple of sensor 1-3 heater strip width doubly, and said housing depth can be 10-15 doubly to the thickness of heater strip.
Said silicon low-grade fever convective acceleration meter adopts silicon materials as stock, adopts the bulk silicon process manufacturing.
The actuating medium of cavity of the present invention adopts the big gas of density when being applied to highly sensitive occasion, and adopts little density gas in the time of the high response frequency of needs.
Principle of work of the present invention is based on thermal convection, but different with United States Patent (USP) 5581034 is: the present invention adopts four temperature sensors that are suitable for the micro-machined scheme of silicon, adopt rectangular cavities, adopt symmetry to split in the heater strip both sides simultaneously to come sense acceleration.Employing rectangular cavities and a plurality of temperature sensor are the sensitivity and the linearities in order to improve signal.
The test circuit of thermal convection acceleration transducer of the present invention adopts bridge circuit, its synoptic diagram as shown in Figure 2, R1 is arm resistance to R4 among the figure, that is four temperature sensors of corresponding accelerometer.
Under the identical situation of other condition, the output voltage signal (having represented the sensitivity of accelerometer) that four temperature sensors are arranged to the bridge circuit scheme can be expressed as:
The output voltage signal of two temperature sensor arrangements is expressed as:
E is a supply voltage in above-mentioned two formulas, and ξ is the temperature-coefficient of electrical resistance of temperature sensor, Δ T
1With Δ T
3Be respectively the temperature difference of two pairs of symmetrical sensors.Because Δ T
3Be negative value, the sensitivity of the acceleration of obvious four temperature sensor arrangements will improve near one times than the sensitivity of two temperature sensor arrangements.The temperature difference and the output voltage that are also noted that formula (1) and (2) in addition are linear, this means that the testing circuit of this accelerometer can obtain the better linearity relation.Because (1) formula of derivation only needs two hypothesis relations, and (2) formula of deriving needs three hypothesis relations, this that is to say the easier acquisition better linearity of the accelerometer degree of the arrangement that adopts four temperature sensors, than the accelerometer of two temperature sensor arrangements, it can improve the linearity.
The response frequency of thermal convection accelerometer is lower in general.Studies show that the key that improves the thermal response frequency is that device size is little, it is less important reasonable actuating medium.The fast development of MEMS technology makes the integrated circuit job operation can be used in the processing of other devices, so device miniatureization is achieved the silicon micro-processing method that this just often says.
Characteristics of the present invention and range of application:
1, adopts silicon micromachining technology to make, have the advantages that size is little, cost is low, performance is good;
2, adopt four temperature sensor symmetric arrangement to come the sense acceleration signal, the sensitivity of device and the linearity are got
To very big raising;
3, structural parameters and actuating medium have been done optimization, made device obtain higher performance;
4, the present invention can use under different occasions, is particularly suitable for measuring high acceleration and exists under the situation of thump
Work.
Description of drawings
Fig. 1 is the structural representation of existing thermal convection accelerometer.
Fig. 2 is the principle schematic of the bridge-type metering circuit among the present invention.
Fig. 3 is the embodiments of the invention structural representation.
Fig. 4 is a bulk silicon process process synoptic diagram of the present invention.
Embodiment
A kind of miniature silicon dridge type thermal convection acceleration transducer embodiment of the present invention's design is described with reference to the accompanying drawings as follows:
The structure of present embodiment as shown in Figure 3, it mainly by silica-based 17, be used to provide cavity 16, heater strip 14, temperature sensor 151,152,153,154 and its corresponding electric contact piece 181,182,183 and 184 in natural convection space to constitute.Silica-based 17 height is 500 μ m, and the length of cavity 16 is 3000 μ m, and width is 910 μ m, highly is 250 μ m.The width of heater strip 14 is 80 μ m, highly is 2 μ m.The width of temperature sensor 15 is 30 μ m, highly is 2 μ m.A pair of temperature sensor 152 and 153 near heater strip is arranged symmetrically in the heater strip both sides, and their distance is 750 μ m.Another also is arranged symmetrically in the heater strip both sides to sensor 151 and 154, and the distance between them is 1050 μ m.
Present embodiment adopts four temperature sensors 151,152,153,154 to come sense acceleration.Test circuit adopts bridge circuit, its synoptic diagram as shown in Figure 2, R1 is arm resistance to R4 among the figure, that is four temperature sensors of accelerometer, 153 and 151 in R1, the R3 corresponding diagram 3 wherein is in R2, the R4 corresponding diagram 3 152 and 154.
Present embodiment adopts the silicon micro-processing method that sensor construction is processed, basic process as shown in Figure 4 because the processing of four sensors is identical, and symmetry in twos, for convenience, the process of only intactly having drawn a sensor among Fig. 4.
At first be on silica-based 19, to form layer of silicon dioxide 20 with damp and hot method for oxidation, precipitation layer of even polysilicon 21 in the LPCVD reactor then, and on face length on the polysilicon another layer silicon dioxide 22 (Fig. 4 (a)).Superincumbent layer of silicon dioxide and polysilicon layer are carried out photoetching so that form heater strip, temperature sensor and electric contact piece.After photoetching, (Fig. 4 (b)) comes out in polysilicon side 23.Form layer of oxide layer 24 in the polysilicon side by oxidizing process again, with the protection polysilicon unaffected during anisotropic etching among the EDP (ethylene diamine-pyrocatechol, a kind of silicon etching agent).By etching, electric contact piece window 25 and cavity window 26 be opened (Fig. 4 (c)) on oxide layer.One deck boron is immersed silicon area so that form the electrode that connects heater strip and well heater subsequently,, the hybrid metal 28 of one deck titanium/gold/copper is sprayed onto its upper surface (Fig. 4 (d)) then by photoresist 27.After this layer metal was stripped from, contiguous block 29 and cavity window 30 formed (Fig. 4 (e)).At last, the whole silica-based etching that is placed among the EDP forms (Fig. 4 (f)) up to cavity 31.
Optimization of the present invention be the analysis showed that temperature sensor is arranged in the sensitivity and the linearity that can improve the thermal convection accelerometer near the place (about 0.3 times of cavity half length) of heater strip.The height of cavity should be higher as far as possible, and 10-15 can avoid owing to the interior mobile performance that has reduced accelerometer of cavity has been restrained in the border effect so doubly to the height of heater strip usually.Aspect the choosing of actuating medium, if improve the sensitivity of thermal convection accelerometer, can adopt bigger gas ratio of density such as carbon dioxide, and will improve response frequency, generally speaking should choose the less gas of density.
Claims (3)
1, a kind of miniature silicon dridge type thermal convection acceleration transducer, it is characterized in that, comprise a seal chamber, a heater strip in this cavity center, be symmetrically placed in two pairs of temperature sensors of these heater strip both sides, and the bridge-type temperature sensing circuit that constitutes by these two pairs of temperature sensors.
2, miniature silicon dridge type thermal convection acceleration transducer according to claim 1, it is characterized in that, said first pair of sensor near heater strip is positioned at apart from heater strip 0.2-0.3 doubly to the position of cavity half length, the position of first couple of sensor 1-3 of second pair of sensor distance heater strip width doubly, said housing depth are that 10-15 is doubly to the thickness of heater strip.
3, miniature silicon dridge type thermal convection acceleration transducer according to claim 1 is characterized in that, said silicon low-grade fever convective acceleration meter adopts silicon materials as stock, adopts the bulk silicon process manufacturing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021168423A CN1161618C (en) | 2002-04-12 | 2002-04-12 | Miniature silicon dridge type heat convection acceleration sensor |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB021168423A CN1161618C (en) | 2002-04-12 | 2002-04-12 | Miniature silicon dridge type heat convection acceleration sensor |
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| CN1373367A true CN1373367A (en) | 2002-10-09 |
| CN1161618C CN1161618C (en) | 2004-08-11 |
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| CNB021168423A Expired - Fee Related CN1161618C (en) | 2002-04-12 | 2002-04-12 | Miniature silicon dridge type heat convection acceleration sensor |
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101187673B (en) * | 2007-12-12 | 2010-06-02 | 美新半导体（无锡）有限公司 | Single-chip tri-axis acceleration sensor |
| CN102556942A (en) * | 2010-12-10 | 2012-07-11 | 中国科学院上海微系统与信息技术研究所 | Manufacturing method of convective acceleration sensor chip based on temperature sensitive resistor |
| TWI477779B (en) * | 2013-06-11 | 2015-03-21 | Univ Chung Hua | Thermal convection type linear accelerometer |
| CN105203250A (en) * | 2015-10-21 | 2015-12-30 | 美新半导体（无锡）有限公司 | Thermal type pressure sensor |
| CN109164274A (en) * | 2018-10-30 | 2019-01-08 | 北京信息科技大学 | A kind of thermally expansive fluid two dimensional accelerometer and its processing method |
| CN112162112A (en) * | 2020-09-25 | 2021-01-01 | 西北工业大学 | Flexible thermal convection acceleration sensor |
-
2002
- 2002-04-12 CN CNB021168423A patent/CN1161618C/en not_active Expired - Fee Related
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101187673B (en) * | 2007-12-12 | 2010-06-02 | 美新半导体（无锡）有限公司 | Single-chip tri-axis acceleration sensor |
| CN102556942A (en) * | 2010-12-10 | 2012-07-11 | 中国科学院上海微系统与信息技术研究所 | Manufacturing method of convective acceleration sensor chip based on temperature sensitive resistor |
| CN102556942B (en) * | 2010-12-10 | 2014-10-22 | 中国科学院上海微系统与信息技术研究所 | Manufacturing method of convective acceleration sensor chip based on temperature sensitive resistor |
| TWI477779B (en) * | 2013-06-11 | 2015-03-21 | Univ Chung Hua | Thermal convection type linear accelerometer |
| CN105203250A (en) * | 2015-10-21 | 2015-12-30 | 美新半导体（无锡）有限公司 | Thermal type pressure sensor |
| CN105203250B (en) * | 2015-10-21 | 2017-10-10 | 美新半导体（无锡）有限公司 | A kind of hot type pressure sensor |
| CN109164274A (en) * | 2018-10-30 | 2019-01-08 | 北京信息科技大学 | A kind of thermally expansive fluid two dimensional accelerometer and its processing method |
| CN112162112A (en) * | 2020-09-25 | 2021-01-01 | 西北工业大学 | Flexible thermal convection acceleration sensor |
| CN112162112B (en) * | 2020-09-25 | 2022-10-28 | 西北工业大学 | Flexible thermal convection acceleration sensor |
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| Publication number | Publication date |
|---|---|
| CN1161618C (en) | 2004-08-11 |
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