EP2738627B1 - Micro-machined vapor cell - Google Patents
Micro-machined vapor cell Download PDFInfo
- Publication number
- EP2738627B1 EP2738627B1 EP13191631.4A EP13191631A EP2738627B1 EP 2738627 B1 EP2738627 B1 EP 2738627B1 EP 13191631 A EP13191631 A EP 13191631A EP 2738627 B1 EP2738627 B1 EP 2738627B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- vapor cell
- hole
- pattern
- silicon element
- micro
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 45
- 229910052710 silicon Inorganic materials 0.000 claims description 45
- 239000010703 silicon Substances 0.000 claims description 45
- 238000000034 method Methods 0.000 claims description 23
- 239000011521 glass Substances 0.000 claims description 13
- 229910052783 alkali metal Inorganic materials 0.000 claims description 9
- 239000000376 reactant Substances 0.000 claims description 7
- 150000001340 alkali metals Chemical class 0.000 claims description 5
- 238000007789 sealing Methods 0.000 claims description 5
- -1 alkali metal azide Chemical class 0.000 claims description 4
- 239000011248 coating agent Substances 0.000 claims description 4
- 238000000576 coating method Methods 0.000 claims description 4
- 238000005530 etching Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000005284 excitation Effects 0.000 description 4
- 229910052792 caesium Inorganic materials 0.000 description 3
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 230000018109 developmental process Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- 230000005283 ground state Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 238000005459 micromachining Methods 0.000 description 2
- 229910052701 rubidium Inorganic materials 0.000 description 2
- IGLNJRXAVVLDKE-UHFFFAOYSA-N rubidium atom Chemical compound [Rb] IGLNJRXAVVLDKE-UHFFFAOYSA-N 0.000 description 2
- 230000001427 coherent effect Effects 0.000 description 1
- 238000004320 controlled atmosphere Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F5/00—Apparatus for producing preselected time intervals for use as timing standards
- G04F5/14—Apparatus for producing preselected time intervals for use as timing standards using atomic clocks
- G04F5/145—Apparatus for producing preselected time intervals for use as timing standards using atomic clocks using Coherent Population Trapping
Definitions
- the invention relates to highly miniaturized atomic clocks.
- the invention particularly concerns micro-machined chip-sized vapor cells with volumes on the order of a few cubic millimeters or less.
- the invention also concerns a method to fabricate the aforementioned vapor cells.
- the unprecedented frequency stability of atomic clocks is achieved by a suitable interrogation of optically excited atoms in order to achieve the hyperfine splitting of the electron state of the reactant, which takes place in the so-called vapor cell, the heart of an atomic clock.
- the vapor cell comprises a sealed cavity, which contains small amounts of suitable reactants: an alkali metal, preferably rubidium or cesium, buffer gas(es), and/or anti-relaxation coating(s).
- MEMS technology allows for fabricating miniaturized vapor cells having a volume in the range of a few cubic millimeters. Silicon micromachining is particularly interesting. It allows a very high level of miniaturization and hybrid integration with control electronics and sensors, and the wafer-level batch fabrication affords a low cost production and higher reproducibility.
- CPT coherent population trapping
- DR double-resonance
- the minimum size of the clock physics package is determined in part by the cavity that confines the microwaves used to excite the atoms. This cavity is usually larger than one-half the wavelength of the microwave radiation used to excite the atomic resonance. For cesium and rubidium, this wavelength is of the order of several centimeters, clearly posing a problem for the development of vapor cell references for portable applications. Thus, CPT or DR excitation is very suitable for micro-machined vapor cells.
- US2006022761 A1 discloses the fabrication of a micro-machined vapor cell comprising a cavity etched in a silicon wafer.
- the cavity is sealed by anodic bonding in its top part and in its bottom part by glass substrates.
- electromagnets could be used for achieving a proper homogeneous magnetic field.
- Helmholtz configuration with two planar coils integrated directly on the two windows of the vapor cell may be a suitable option.
- planar coils realized in MEMS technology are characterized by a very low thickness of the coil, typically in the range of some hundreds of nanometer. As a consequence, a planar coil has a relatively high electrical resistance and hence an elevated power dissipation. Thus, a skilled person is not encouraged to investigate planar coils for providing a homogeneous magnetic field in a miniaturized vapor cell.
- the object of this invention is to at least partially overcome the limitations described, and thereby provide a versatile simple configuration using electromagnets to create the needed homogeneous magnetic field on the vapor cell boosting the methods of miniaturization and providing a favorable simplicity to efficiency ratio.
- the invention relates to a micro-machined vapor cell according to independent claim 1.
- Such a vapor cell presents the advantage that the magnetic means don't add significant additional volume.
- Another advantage of this solution is its very low electrical resistivity compared to a planar coil realized in MEMS technology.
- the object of the invention contributes to the development of highly miniaturized atomic clocks using simple configurations in order to simplify and to improve the control of the assembled components.
- the invention also concerns a method to fabricate the aforementioned vapor cell according to independent claim 6.
- Figure 1 shows a micro-machined vapor cell 1 according to the invention comprising:
- the cavity is preferably cylindrical but other shapes can be obviously used.
- the vapor cell 1 comprises furthermore a solenoid 50 arranged to provide a homogeneous magnetic field to said vapor cell 1.
- the solenoid 50 is coiled directly on the vapor cell 1 that defines the core of this solenoid 50. More precisely, the wire forming the solenoid is coiled along the longitudinal axis of the cavity, along the external surface 25 of the central silicon element 10.
- the solenoid provides a homogeneous magnetic field to the vapor cell 1 with the advantage that not significant additional volume is added to the vapor cell 1, achieving an important goal of the invention.
- Figure 1 presents two identical enlarged vapor cells 1, one of them showing through its upper sealing cap 40 the central silicon element 10, the cavity 20 being visible.
- the different components of the vapor cell 1, the two glass caps 30 and 40 and the external surface 25 of the central silicon element 10, are arranged to keep the solenoid 50 in a substantially fixed, at least stable, position without the risk that it glides off. Essentially, the solenoid 50 has to be maintained between the two caps 30 and 40 that define banking means for the solenoid 50.
- the central silicon element 10 has a dodecagonal shaped external surface 25 while the two glass caps 30 and 40, closing the cavity 20, have a quadratic shape with the particularity that they define limitation means for the solenoid 50 and that they exceed the footprint of the central silicon element 10, defined by its external surface.
- different cap shapes could also be used as an ellipse or a regular polygon.
- Other banking means may be considered, in addition to the sealing means. Hooks or notches can be considered, extending over the footprint of the central silicon element 10. Nevertheless, the quadratic shape of the caps 30 and 40 simplifies the fabrication process of the vapor cells 1 according to the invention as it is going to be described further.
- the external surface 25 of the central silicon element 10 has preferably a regular polygonal shape, which could be an octagonal shape, but also a dodecagonal shape as said before, or a hexadecagonal shape, or any regular polygonal shapes having (n * 4) number of segments, where n is an integer and it is equal or greater than 2.
- the different shapes of the glass caps 30 and 40 and the external surface 25 of the central silicon element 10 are obtained in the fabrication method by a combination of etching and dicing processes.
- figure 2 presents two different patterns of holes 11 and 12 that are etched through a silicon wafer.
- the first hole-pattern 11 consists of circular holes required for the vapor cell cavities 20 that are arranged in regularly spaced columns and rows.
- the second hole-pattern 12 consists of holes having a star shape. The figure shows that this star shape is formed by four peaks 12A, 12B, 12C and 12D, each peak being arranged perpendicularly in reference to its two adjacent peaks.
- the second hole-pattern 12 is offset towards the first hole-pattern 11 by half the column spacing and half the row spacing.
- a silicon wafer square matrix is presented showing sixteen first circular hole-patterns 11 and nine second hole-patterns 12; this is going turn out that sixteen singular vapor cells 1 are going to be formed following the method of fabrication illustrated in this non limiting example.
- the shape of the second hole-pattern 12 is chosen in function of the desired external surface 25 shape of the central silicon element 10, as illustrated in figure 4 to figure 6 .
- figure 4 illustrates a second hole-pattern 12 showing the shape of a four-peaks star, in this case the four-peaks star is a rhombus (square), and it is formed by four adjacent octagons formed by eight external surface segments 14 that represent the external surface 25 shape of the central silicon element 10.
- the four-peaks star has eight peak star segments 13 and it is formed by four adjacent dodecagons formed by twelve external surface segments 14; and in that way, figure 6 illustrates a four-peaks star having twelve peak star segments 13 and it is formed by four adjacent hexadecagons formed by sixteen external surface segments 14.
- the four-peaks star gets more and more segments 13 too.
- the four-peaks stars are formed by a number of (m * 4) segments 13, where m is an integer, equal to or greater than 1 and depending on the desired regular polygonal shape of the central silicon element external surface 25.
- the peak star segments 13 plays an important role in the dicing process following the method presented hereafter.
- two lines A and B define the dicing directions. These lines A and B intersect perpendicularly in the center of the second hole-pattern 12 (the four-peak star shape), each line connecting opposite peaks of the star.
- Line A connects two peaks of the star 12A and 12B
- line B connects the other two peaks of the star 12C and 12D. All the second hole-patterns 12 are identical, so, the definition of the lines A and B could be defined by any one of the second hole-patterns 12.
- the next fabrication steps are the anodic bonding of a first glass wafer to one side of the silicon wafer (the bottom side of the etched silicon wafer) to form a first cap 30 to seal it.
- the filling of the cavities 20 with the required reactants such as an alkali metal or an alkali metal azide.
- the bonding of a second glass wafer to the other side of the silicon wafer also to form a second cap 40 to seal it, preferably under controlled atmosphere.
- the bonded wafer stack is diced along the lines A and B defined by the shape of the second hole-pattern 12.
- the solenoid 50 is then coiled directly on the central silicon element 10, the first 30 and second 40 glass caps defining banking means to keep it in a substantially fixed position without the risk that it glides off.
- the volume of the vapor cell 1 is lower than 100 mm 3 , preferably even less than 1 mm 3 .
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Ecology (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Micromachines (AREA)
Description
- The invention relates to highly miniaturized atomic clocks. The invention particularly concerns micro-machined chip-sized vapor cells with volumes on the order of a few cubic millimeters or less. The invention also concerns a method to fabricate the aforementioned vapor cells.
- Miniaturized atomic clocks characterized by a small size and a drastically reduced power consumption compared to standard atomic clocks exhibit an increasing interest mainly for applications in portable devices. The unprecedented frequency stability of atomic clocks is achieved by a suitable interrogation of optically excited atoms in order to achieve the hyperfine splitting of the electron state of the reactant, which takes place in the so-called vapor cell, the heart of an atomic clock. The vapor cell comprises a sealed cavity, which contains small amounts of suitable reactants: an alkali metal, preferably rubidium or cesium, buffer gas(es), and/or anti-relaxation coating(s).
- MEMS technology allows for fabricating miniaturized vapor cells having a volume in the range of a few cubic millimeters. Silicon micromachining is particularly interesting. It allows a very high level of miniaturization and hybrid integration with control electronics and sensors, and the wafer-level batch fabrication affords a low cost production and higher reproducibility.
- Various atom excitation techniques have been investigated concerning the field of miniaturized atomic clocks developments. One alternative includes coherent population trapping (CPT) by means of a modulated laser, while another alternative is based on double-resonance (DR) microwave excitation by means of a modulated magnetic field.
- In most vapor cell frequency references, which do not use CPT or DR, the minimum size of the clock physics package is determined in part by the cavity that confines the microwaves used to excite the atoms. This cavity is usually larger than one-half the wavelength of the microwave radiation used to excite the atomic resonance. For cesium and rubidium, this wavelength is of the order of several centimeters, clearly posing a problem for the development of vapor cell references for portable applications. Thus, CPT or DR excitation is very suitable for micro-machined vapor cells.
-
US2006022761 A1 discloses the fabrication of a micro-machined vapor cell comprising a cavity etched in a silicon wafer. The cavity is sealed by anodic bonding in its top part and in its bottom part by glass substrates. - L-A Liew, Appl. Phys. Lett. 84, 2694 (2004) discloses a method to fabricate millimeter sized cesium vapor cells using silicon micromachining and anodic bonding techniques, where the frequency reference is based on optical excitation and CPT interrogation. The results presented in this work show that it is possible to design and build frequency references far smaller than known in the prior art before even if it results in a complicated interrogation optics assembly highlighted by the miniaturization conditions.
- In addition, in order to realize a working CPT or DR atomic clock a magnetic field has to be provided which is required to be homogeneous inside the vapor cell in order to achieve ground-state hyperfine splitting of the alkali atoms.
- There are different ways to create the needed homogeneous magnetic field. One option is the use of permanent magnets, but they present the disadvantage that the strength of the magnetic field cannot be adjusted, and that they make the final device quite bulky.
- On the other hand, electromagnets could be used for achieving a proper homogeneous magnetic field. Helmholtz configuration with two planar coils integrated directly on the two windows of the vapor cell may be a suitable option. However, the Helmholtz condition r = d (where r is the radius of the coil and d is the distance between the two coils) must be fulfilled in order to obtain a homogeneous magnetic field, a requirement which limits downsizing of the vapor cells. Moreover, planar coils realized in MEMS technology are characterized by a very low thickness of the coil, typically in the range of some hundreds of nanometer. As a consequence, a planar coil has a relatively high electrical resistance and hence an elevated power dissipation. Thus, a skilled person is not encouraged to investigate planar coils for providing a homogeneous magnetic field in a miniaturized vapor cell.
- The object of this invention is to at least partially overcome the limitations described, and thereby provide a versatile simple configuration using electromagnets to create the needed homogeneous magnetic field on the vapor cell boosting the methods of miniaturization and providing a favorable simplicity to efficiency ratio.
- To this end, the invention relates to a micro-machined vapor cell according to
independent claim 1. - Such a vapor cell presents the advantage that the magnetic means don't add significant additional volume. Another advantage of this solution is its very low electrical resistivity compared to a planar coil realized in MEMS technology.
- Thus, the object of the invention contributes to the development of highly miniaturized atomic clocks using simple configurations in order to simplify and to improve the control of the assembled components.
- The invention also concerns a method to fabricate the aforementioned vapor cell according to independent claim 6.
- Further characteristics and details of this invention are explained in the following detailed description of the invention and in the claims.
- The above described objects and advantages of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed descriptions and accompanying drawings, in which:
-
figure 1 illustrates a vapor cell according to the invention; -
figures 2 and 3 illustrate different aspects of the method of vapor cell's fabrication according to the invention; and -
figures 4 to 6 illustrate different regular polygonal shapes of the external surface of the central silicon element etched through the silicon wafer, and different shapes of the second hole-pattern also etched trough the silicon wafer. -
Figure 1 shows amicro-machined vapor cell 1 according to the invention comprising: - a
central silicon element 10 forming acavity 20 containing vapor cell reactants such as alkali metal or alkali metal azide, buffer gas(es), and/or anti relaxation coating(s); and - a first 30 and a second 40 glass caps sealing the
cavity 20. - The cavity is preferably cylindrical but other shapes can be obviously used.
- The present invention being not particularly directed to the reactants suitable for obtaining a vapor cell, this aspect will not be described in details and the scope of the protection is not limited by the example provided.
- The
vapor cell 1 comprises furthermore asolenoid 50 arranged to provide a homogeneous magnetic field to saidvapor cell 1. According to the invention, thesolenoid 50 is coiled directly on thevapor cell 1 that defines the core of thissolenoid 50. More precisely, the wire forming the solenoid is coiled along the longitudinal axis of the cavity, along theexternal surface 25 of thecentral silicon element 10. The solenoid provides a homogeneous magnetic field to thevapor cell 1 with the advantage that not significant additional volume is added to thevapor cell 1, achieving an important goal of the invention. -
Figure 1 presents two identical enlargedvapor cells 1, one of them showing through its upper sealingcap 40 thecentral silicon element 10, thecavity 20 being visible. The different components of thevapor cell 1, the twoglass caps external surface 25 of thecentral silicon element 10, are arranged to keep thesolenoid 50 in a substantially fixed, at least stable, position without the risk that it glides off. Essentially, thesolenoid 50 has to be maintained between the twocaps solenoid 50. - In the example presented here, the
central silicon element 10 has a dodecagonal shapedexternal surface 25 while the twoglass caps cavity 20, have a quadratic shape with the particularity that they define limitation means for thesolenoid 50 and that they exceed the footprint of thecentral silicon element 10, defined by its external surface. In other examples, different cap shapes could also be used as an ellipse or a regular polygon. Other banking means may be considered, in addition to the sealing means. Hooks or notches can be considered, extending over the footprint of thecentral silicon element 10. Nevertheless, the quadratic shape of thecaps vapor cells 1 according to the invention as it is going to be described further. - The
external surface 25 of thecentral silicon element 10 has preferably a regular polygonal shape, which could be an octagonal shape, but also a dodecagonal shape as said before, or a hexadecagonal shape, or any regular polygonal shapes having (n * 4) number of segments, where n is an integer and it is equal or greater than 2. - The different shapes of the
glass caps external surface 25 of thecentral silicon element 10 are obtained in the fabrication method by a combination of etching and dicing processes. - The method to fabricate the described
vapor cell 1 according to the invention is principally illustrated usingfigures 2 and 3 . - In this example,
figure 2 presents two different patterns ofholes pattern 11 consists of circular holes required for thevapor cell cavities 20 that are arranged in regularly spaced columns and rows. The second hole-pattern 12 consists of holes having a star shape. The figure shows that this star shape is formed by fourpeaks pattern 12 is offset towards the first hole-pattern 11 by half the column spacing and half the row spacing. In this figure a silicon wafer square matrix is presented showing sixteen first circular hole-patterns 11 and nine second hole-patterns 12; this is going turn out that sixteensingular vapor cells 1 are going to be formed following the method of fabrication illustrated in this non limiting example. - The shape of the second hole-
pattern 12 is chosen in function of the desiredexternal surface 25 shape of thecentral silicon element 10, as illustrated infigure 4 to figure 6 . For example,figure 4 illustrates a second hole-pattern 12 showing the shape of a four-peaks star, in this case the four-peaks star is a rhombus (square), and it is formed by four adjacent octagons formed by eightexternal surface segments 14 that represent theexternal surface 25 shape of thecentral silicon element 10. In another example illustrated infigure 5 , the four-peaks star has eightpeak star segments 13 and it is formed by four adjacent dodecagons formed by twelveexternal surface segments 14; and in that way,figure 6 illustrates a four-peaks star having twelvepeak star segments 13 and it is formed by four adjacent hexadecagons formed by sixteenexternal surface segments 14. By adding more andmore segments 14 to the regular polygonalcentral silicon element 10, the four-peaks star gets more andmore segments 13 too. Thus, the four-peaks stars are formed by a number of (m * 4)segments 13, where m is an integer, equal to or greater than 1 and depending on the desired regular polygonal shape of the central silicon elementexternal surface 25. - We note that n and m tending to infinity, the external shape of the
central silicon elements 10 tend to a circular shape. - The
peak star segments 13 plays an important role in the dicing process following the method presented hereafter. Thus, two lines A and B define the dicing directions. These lines A and B intersect perpendicularly in the center of the second hole-pattern 12 (the four-peak star shape), each line connecting opposite peaks of the star. Line A connects two peaks of thestar star patterns 12 are identical, so, the definition of the lines A and B could be defined by any one of the second hole-patterns 12. - It should be noticed that when etching the second hole-
pattern 12, allsegments 14 of the regular polygonalexternal surface 25 of thecentral silicon element 10 are formed up, except thesegments 14 that relies the differentcentral silicon elements 10, that is the twoadjacent segments 14 crossed by the line A and the twoadjacent segments 14 crossed by the line B, that is where thefuture vapor cells 1 are still connected to their direct neighbors (attaches) before dicing process. - Although the silicon wafer has many holes, the wafer is still stable and can be easily manipulated. The next fabrication steps are the anodic bonding of a first glass wafer to one side of the silicon wafer (the bottom side of the etched silicon wafer) to form a
first cap 30 to seal it. After, the filling of thecavities 20 with the required reactants, such as an alkali metal or an alkali metal azide. Then the bonding of a second glass wafer to the other side of the silicon wafer (the top side of the etched silicon wafer) also to form asecond cap 40 to seal it, preferably under controlled atmosphere. Then, the bonded wafer stack is diced along the lines A and B defined by the shape of the second hole-pattern 12. Finally, the result is shown infigure 3 where the vapor cell matrix is clearly visible after the dicing process; sixteensingular vapor cells 1 were fabricated following the method according to the invention. The sealingcap 40 of one of thecentral silicon elements 10 is not represented to show the components between the layers of the bonded wafer stacks. - The
solenoid 50 is then coiled directly on thecentral silicon element 10, the first 30 and second 40 glass caps defining banking means to keep it in a substantially fixed position without the risk that it glides off. - It is therefore obtained a
micro-machined vapor cell 1 equipped with asolenoid 50 that provides the needed homogeneous magnetic field in order to achieve ground-state hyperfine splitting of the alkali atoms. Thanks to this configuration and to the above-described process, the volume of thevapor cell 1 is lower than 100 mm3, preferably even less than 1 mm3.
Claims (10)
- Micro-machined vapor cell (1) comprising:- a central silicon element (10) forming a cavity (20) containing vapor cell reactants such as alkali metal or alkali metal azide, buffer gas(es), and/or anti relaxation coating(s),- a first (30) and a second (40) glass caps sealing the cavity (20), and- a solenoid (50) arranged to provide a homogeneous magnetic field to said vapor cell (1) characterized in thatthe solenoid (50) is coiled directly on the central silicon element (10), which forms the core of the solenoid (50);
the first (30) and second (40) glass caps define banking means to keep the solenoid (50) coiled on the central silicon element (10). - The micro-machined vapor cell (1) according to claim 1, characterized in that the first (30) and second (40) glass caps exceed the central silicon element (10).
- The micro-machined vapor cell (1) according to any one of claims 1 and 2, characterized in that the central silicon element (10) shows an external surface (25) having a regular polygonal shape.
- The micro-machined vapor cell (1) according to claim 3,characterized in that the regular polygonal shape external surface (25) of the central silicon element (10) is an octagon, a dodecagon, a hexadecagon, and all regular polygonal shapes having a number of (n * 4) segments, where n is an integer equal or greater than 2.
- The micro-machined vapor cell (1) according to any one of claims 1 to 4, characterized in that the vapor cell volume is lower than 100 mm3.
- Method to fabricate the micro-machined vapor cell (1) according to any one of the previous claims and comprising the following steps:- providing a silicon wafer,- etching a first hole-pattern (11) and a second hole-pattern (12) through said silicon wafer to form holes constituting cavities (20),- anodic bonding a first glass wafer on the bottom of the etched silicon wafer to form a first cap (30),- filling the holes with vapor cell reactants such as alkali metal or alkali metal azide, buffer gas(es), and/or anti relaxation coating(s),- anodic bonding a second glass wafer on the top of the etched silicon wafer to form a second cap (40), a bonded wafer stack being obtained,- dicing said bonded wafer stack along lines (A and B) defined by the shape of the second hole-pattern (12), and- coiling a solenoid (50) directly on the central silicon element (10) between the first cap and the second cap defining banking means to keep the solenoid (50) coiled on the central silicon element (10).
- The method according to claim 6, characterized in that the first hole-pattern (11) and the second hole-pattern (12) are arranged in regular columns and rows through the silicon wafer.
- The method according to any one of claims 6 and 7, characterized in that the shape of the second hole-pattern (12) is a four-peak star.
- The method according to claim 8,characterized in that the four-peaks stars are formed by (m * 4) segments, where m is an integer equal to or greater than 1 and depends of the desired regular polygonal shape external surface (25) of the central silicon element (10).
- The method according to any one of claims 8 to 9, characterized in that the dicing process follows two perpendicular lines (A and B) that cross in the center of the second hole-pattern (12), each line connecting opposite peaks of the star.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201261722468P | 2012-11-05 | 2012-11-05 |
Publications (3)
Publication Number | Publication Date |
---|---|
EP2738627A2 EP2738627A2 (en) | 2014-06-04 |
EP2738627A3 EP2738627A3 (en) | 2015-02-18 |
EP2738627B1 true EP2738627B1 (en) | 2021-05-12 |
Family
ID=49546292
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP13191631.4A Active EP2738627B1 (en) | 2012-11-05 | 2013-11-05 | Micro-machined vapor cell |
Country Status (1)
Country | Link |
---|---|
EP (1) | EP2738627B1 (en) |
Families Citing this family (31)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP6957187B2 (en) * | 2017-04-18 | 2021-11-02 | 浜松ホトニクス株式会社 | Chip manufacturing method and silicon chip |
US10976386B2 (en) | 2018-07-17 | 2021-04-13 | Hi Llc | Magnetic field measurement system and method of using variable dynamic range optical magnetometers |
WO2020036666A1 (en) | 2018-08-17 | 2020-02-20 | Hi Llc | Optically pumped magnetometer |
WO2020040882A1 (en) | 2018-08-20 | 2020-02-27 | Hi Llc | Magnetic field shaping components for magnetic field measurement systems and methods for making and using |
US10627460B2 (en) | 2018-08-28 | 2020-04-21 | Hi Llc | Systems and methods including multi-mode operation of optically pumped magnetometer(s) |
US11237225B2 (en) | 2018-09-18 | 2022-02-01 | Hi Llc | Dynamic magnetic shielding and beamforming using ferrofluid for compact Magnetoencephalography (MEG) |
US11370941B2 (en) | 2018-10-19 | 2022-06-28 | Hi Llc | Methods and systems using molecular glue for covalent bonding of solid substrates |
US11307268B2 (en) | 2018-12-18 | 2022-04-19 | Hi Llc | Covalently-bound anti-relaxation surface coatings and application in magnetometers |
US11294008B2 (en) | 2019-01-25 | 2022-04-05 | Hi Llc | Magnetic field measurement system with amplitude-selective magnetic shield |
EP3924743A1 (en) | 2019-02-12 | 2021-12-22 | Hi LLC | Neural feedback loop filters for enhanced dynamic range magnetoencephalography (meg) systems and methods |
CA3130157A1 (en) | 2019-03-29 | 2020-10-08 | Hi Llc | Integrated magnetometer arrays for magnetoencephalography (meg) detection systems and methods |
US11269027B2 (en) | 2019-04-23 | 2022-03-08 | Hi Llc | Compact optically pumped magnetometers with pump and probe configuration and systems and methods |
US11506730B2 (en) | 2019-05-03 | 2022-11-22 | Hi Llc | Magnetic field measurement systems including a plurality of wearable sensor units having a magnetic field generator |
US11839474B2 (en) | 2019-05-31 | 2023-12-12 | Hi Llc | Magnetoencephalography (MEG) phantoms for simulating neural activity |
US11131729B2 (en) | 2019-06-21 | 2021-09-28 | Hi Llc | Systems and methods with angled input beams for an optically pumped magnetometer |
US11415641B2 (en) | 2019-07-12 | 2022-08-16 | Hi Llc | Detachable arrangement for on-scalp magnetoencephalography (MEG) calibration |
US10996293B2 (en) | 2019-08-06 | 2021-05-04 | Hi Llc | Systems and methods having an optical magnetometer array with beam splitters |
WO2021045953A1 (en) | 2019-09-03 | 2021-03-11 | Hi Llc | Methods and systems for fast field zeroing for magnetoencephalography (meg) |
US11474129B2 (en) | 2019-11-08 | 2022-10-18 | Hi Llc | Methods and systems for homogenous optically-pumped vapor cell array assembly from discrete vapor cells |
CN111024123B (en) * | 2019-12-18 | 2022-01-21 | 北京航空航天大学 | Method for manufacturing multi-layer OTS coating in alkali metal air chamber |
US11604236B2 (en) | 2020-02-12 | 2023-03-14 | Hi Llc | Optimal methods to feedback control and estimate magnetic fields to enable a neural detection system to measure magnetic fields from the brain |
US11980466B2 (en) | 2020-02-12 | 2024-05-14 | Hi Llc | Nested and parallel feedback control loops for ultra-fine measurements of magnetic fields from the brain using a neural detection system |
US11872042B2 (en) | 2020-02-12 | 2024-01-16 | Hi Llc | Self-calibration of flux gate offset and gain drift to improve measurement accuracy of magnetic fields from the brain using a wearable neural detection system |
US11801003B2 (en) | 2020-02-12 | 2023-10-31 | Hi Llc | Estimating the magnetic field at distances from direct measurements to enable fine sensors to measure the magnetic field from the brain using a neural detection system |
US11977134B2 (en) | 2020-02-24 | 2024-05-07 | Hi Llc | Mitigation of an effect of capacitively coupled current while driving a sensor component over an unshielded twisted pair wire configuration |
US11428756B2 (en) | 2020-05-28 | 2022-08-30 | Hi Llc | Magnetic field measurement or recording systems with validation using optical tracking data |
WO2021242682A1 (en) | 2020-05-28 | 2021-12-02 | Hi Llc | Systems and methods for recording biomagnetic fields of the human heart |
WO2021242680A1 (en) | 2020-05-28 | 2021-12-02 | Hi Llc | Systems and methods for recording neural activity |
US11766217B2 (en) | 2020-05-28 | 2023-09-26 | Hi Llc | Systems and methods for multimodal pose and motion tracking for magnetic field measurement or recording systems |
US11604237B2 (en) | 2021-01-08 | 2023-03-14 | Hi Llc | Devices, systems, and methods with optical pumping magnetometers for three-axis magnetic field sensing |
US11803018B2 (en) | 2021-01-12 | 2023-10-31 | Hi Llc | Devices, systems, and methods with a piezoelectric-driven light intensity modulator |
Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101774529A (en) * | 2010-01-26 | 2010-07-14 | 北京航空航天大学 | MEMS atom cavity chip and preparation method thereof |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6265945B1 (en) * | 1999-10-25 | 2001-07-24 | Kernco, Inc. | Atomic frequency standard based upon coherent population trapping |
US20050007118A1 (en) * | 2003-04-09 | 2005-01-13 | John Kitching | Micromachined alkali-atom vapor cells and method of fabrication |
WO2006036268A2 (en) * | 2004-07-16 | 2006-04-06 | Sarnoff Corporation | Chip-scale atomic clock (csac) and method for making same |
-
2013
- 2013-11-05 EP EP13191631.4A patent/EP2738627B1/en active Active
Patent Citations (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101774529A (en) * | 2010-01-26 | 2010-07-14 | 北京航空航天大学 | MEMS atom cavity chip and preparation method thereof |
Also Published As
Publication number | Publication date |
---|---|
EP2738627A2 (en) | 2014-06-04 |
EP2738627A3 (en) | 2015-02-18 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
EP2738627B1 (en) | Micro-machined vapor cell | |
US9461659B2 (en) | Micro-machined vapor cell | |
Kitching | Chip-scale atomic devices | |
Pétremand et al. | Microfabricated rubidium vapour cell with a thick glass core for small-scale atomic clock applications | |
US10024929B2 (en) | Vapor cell structure having cavities connected by channels for micro-fabricated atomic clocks, magnetometers, and other devices | |
Eklund et al. | Glass-blown spherical microcells for chip-scale atomic devices | |
Xia et al. | The development of micromachined gyroscope structure and circuitry technology | |
CN104737246A (en) | Through substrate via inductors | |
JP6515091B2 (en) | MEMS device having a getter layer | |
US9753280B2 (en) | Micromirror arrangement | |
US20140247269A1 (en) | High density, low loss 3-d through-glass inductor with magnetic core | |
McGilligan et al. | Micro-fabricated components for cold atom sensors | |
Glenday et al. | Limits on anomalous spin-spin couplings between neutrons | |
US8950552B2 (en) | Mainspring comprising supplementary energy accumulation curves | |
CN105973217A (en) | Miniature nuclear magnetic resonance gyro air chamber | |
US8981874B2 (en) | Resonator device and method of optimizing a Q-factor | |
US8465660B2 (en) | Fabrication process of a microfabricated blazed grating | |
Hamamda et al. | Ro-vibrational cooling of molecules and prospects | |
Hasegawa et al. | Effects of getters on hermetically sealed micromachined cesium–neon cells for atomic clocks | |
Artioli et al. | Design of quantum dot-nanowire single-photon sources that are immune to thermomechanical decoherence | |
Néel et al. | Aluminum nitride photonic crystals and microdiscs for ultra-violet nanophotonics | |
US8358881B2 (en) | High-Q resonators assembly | |
CN110998854B (en) | Molecular spectroscopic chamber with resonant cavity | |
EP3843426A1 (en) | Sound producing device | |
GB2587331A (en) | Single photon sources |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
17P | Request for examination filed |
Effective date: 20131105 |
|
AK | Designated contracting states |
Kind code of ref document: A2 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G04F 5/14 20060101AFI20140922BHEP Ipc: H03L 7/26 20060101ALI20140922BHEP |
|
PUAL | Search report despatched |
Free format text: ORIGINAL CODE: 0009013 |
|
AK | Designated contracting states |
Kind code of ref document: A3 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
AX | Request for extension of the european patent |
Extension state: BA ME |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G04F 5/14 20060101AFI20150109BHEP Ipc: H03L 7/26 20060101ALI20150109BHEP |
|
R17P | Request for examination filed (corrected) |
Effective date: 20150703 |
|
RBV | Designated contracting states (corrected) |
Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
17Q | First examination report despatched |
Effective date: 20200320 |
|
RIC1 | Information provided on ipc code assigned before grant |
Ipc: G04F 5/14 20060101AFI20201023BHEP |
|
GRAP | Despatch of communication of intention to grant a patent |
Free format text: ORIGINAL CODE: EPIDOSNIGR1 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: GRANT OF PATENT IS INTENDED |
|
INTG | Intention to grant announced |
Effective date: 20201208 |
|
RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: OVERSTOLZ, THOMAS Inventor name: HAESLER, JACQUES |
|
GRAS | Grant fee paid |
Free format text: ORIGINAL CODE: EPIDOSNIGR3 |
|
GRAA | (expected) grant |
Free format text: ORIGINAL CODE: 0009210 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE PATENT HAS BEEN GRANTED |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R083 Ref document number: 602013077432 Country of ref document: DE |
|
AK | Designated contracting states |
Kind code of ref document: B1 Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR |
|
REG | Reference to a national code |
Ref country code: GB Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: CH Ref legal event code: EP |
|
RIN2 | Information on inventor provided after grant (corrected) |
Inventor name: HAESLER, JACQUES Inventor name: OVERSTOLZ, THOMAS |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R096 Ref document number: 602013077432 Country of ref document: DE |
|
REG | Reference to a national code |
Ref country code: IE Ref legal event code: FG4D |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: REF Ref document number: 1392584 Country of ref document: AT Kind code of ref document: T Effective date: 20210615 |
|
REG | Reference to a national code |
Ref country code: LT Ref legal event code: MG9D |
|
REG | Reference to a national code |
Ref country code: AT Ref legal event code: MK05 Ref document number: 1392584 Country of ref document: AT Kind code of ref document: T Effective date: 20210512 |
|
REG | Reference to a national code |
Ref country code: NL Ref legal event code: MP Effective date: 20210512 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: AT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: BG Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210812 Ref country code: HR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: LT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: FI Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: PT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210913 Ref country code: PL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: NO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210812 Ref country code: ES Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: GR Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210813 Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210912 Ref country code: LV Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: SE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: RS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: NL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CZ Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: EE Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: DK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: SM Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: SK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: RO Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
REG | Reference to a national code |
Ref country code: DE Ref legal event code: R097 Ref document number: 602013077432 Country of ref document: DE |
|
PLBE | No opposition filed within time limit |
Free format text: ORIGINAL CODE: 0009261 |
|
STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT |
|
26N | No opposition filed |
Effective date: 20220215 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IS Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210912 Ref country code: AL Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MC Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: LU Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20211105 Ref country code: IT Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 Ref country code: BE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20211130 |
|
REG | Reference to a national code |
Ref country code: BE Ref legal event code: MM Effective date: 20211130 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: IE Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES Effective date: 20211105 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: HU Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO Effective date: 20131105 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: CY Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: GB Payment date: 20231123 Year of fee payment: 11 |
|
PGFP | Annual fee paid to national office [announced via postgrant information from national office to epo] |
Ref country code: FR Payment date: 20231123 Year of fee payment: 11 Ref country code: DE Payment date: 20231120 Year of fee payment: 11 Ref country code: CH Payment date: 20231201 Year of fee payment: 11 |
|
PG25 | Lapsed in a contracting state [announced via postgrant information from national office to epo] |
Ref country code: MK Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT Effective date: 20210512 |