WO1993012534A1 - Energy analyser - Google Patents
Energy analyser Download PDFInfo
- Publication number
- WO1993012534A1 WO1993012534A1 PCT/GB1992/002308 GB9202308W WO9312534A1 WO 1993012534 A1 WO1993012534 A1 WO 1993012534A1 GB 9202308 W GB9202308 W GB 9202308W WO 9312534 A1 WO9312534 A1 WO 9312534A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- electrode layer
- layer
- charged particles
- collector electrode
- collector
- Prior art date
Links
- 239000002245 particle Substances 0.000 claims abstract description 35
- 239000011810 insulating material Substances 0.000 claims description 9
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 claims description 3
- 229910052721 tungsten Inorganic materials 0.000 claims description 3
- 239000010937 tungsten Substances 0.000 claims description 3
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 2
- 229910002804 graphite Inorganic materials 0.000 claims description 2
- 239000010439 graphite Substances 0.000 claims description 2
- 238000012545 processing Methods 0.000 abstract description 4
- 150000002500 ions Chemical class 0.000 description 10
- 229920002120 photoresistant polymer Polymers 0.000 description 6
- 238000005530 etching Methods 0.000 description 4
- 239000011521 glass Substances 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- 230000000979 retarding effect Effects 0.000 description 4
- 238000000034 method Methods 0.000 description 3
- 238000005086 pumping Methods 0.000 description 3
- 239000000758 substrate Substances 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 238000009826 distribution Methods 0.000 description 2
- 238000001312 dry etching Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- PLFFHJWXOGYWPR-HEDMGYOXSA-N (4r)-4-[(3r,3as,5ar,5br,7as,11as,11br,13ar,13bs)-5a,5b,8,8,11a,13b-hexamethyl-1,2,3,3a,4,5,6,7,7a,9,10,11,11b,12,13,13a-hexadecahydrocyclopenta[a]chrysen-3-yl]pentan-1-ol Chemical compound C([C@]1(C)[C@H]2CC[C@H]34)CCC(C)(C)[C@@H]1CC[C@@]2(C)[C@]4(C)CC[C@@H]1[C@]3(C)CC[C@@H]1[C@@H](CCCO)C PLFFHJWXOGYWPR-HEDMGYOXSA-N 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 239000003989 dielectric material Substances 0.000 description 1
- 238000010894 electron beam technology Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 238000010884 ion-beam technique Methods 0.000 description 1
- 238000002488 metal-organic chemical vapour deposition Methods 0.000 description 1
- 238000001020 plasma etching Methods 0.000 description 1
- 229910021420 polycrystalline silicon Inorganic materials 0.000 description 1
- 238000005036 potential barrier Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000001039 wet etching Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/32—Gas-filled discharge tubes
- H01J37/32917—Plasma diagnostics
- H01J37/32935—Monitoring and controlling tubes by information coming from the object and/or discharge
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/244—Detectors; Associated components or circuits therefor
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J49/00—Particle spectrometers or separator tubes
- H01J49/02—Details
- H01J49/025—Detectors specially adapted to particle spectrometers
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
- H01J2237/244—Detection characterized by the detecting means
- H01J2237/2444—Electron Multiplier
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2237/00—Discharge tubes exposing object to beam, e.g. for analysis treatment, etching, imaging
- H01J2237/244—Detection characterized by the detecting means
- H01J2237/24485—Energy spectrometers
Definitions
- This invention relates to an energy analyser for measuring the energy of charged particles which are incident on a planar surface in a low-pressure environment, such as, for example, in a plasma processing equipment.
- an energy measuring device comprising a monolithic structure including a planar collector electrode layer and a. rejection electrode layer separated from the collector electrode layer by a first layer of insulating material, said rejection electrode layer and said first layer of insulating material being apertured to allow charged particles from a source of charged particles to flow therethrough towards the collector electrode layer; the device further comprising electrical potential supply means for biasing the collector electrode layer and the rejection electrode layer to cause charged particles of a given polarity and of kinetic energy less than a predetermined level to be repelled away from the collector electrode layer so that the collector electrode layer receives only particles of said given polarity having a kinetic energy equal to or greater than said level; and means to measure the quantity of charged particles reaching the collector electrode layer.
- the collector electrode layer is preferably biased to repel said particles having a kinetic energy less than said predetermined level.
- the rejection electrode layer is preferably biased to reject charged particles of the opposite polarity.
- the monolithic structure may also include an apertured shielding electrode layer separated from the rejection electrode layer by a second layer of insulating material, the shielding electrode layer serving to shield the source of charged particles from the potential applied within the monolithic structure. Further apertured shielding electrode layers may also be provided.
- Figure 1 is a schematic plan view of a monolithic structure for use in the present invention
- Figure 2 is a schematic cross-sectional view taken along a line II-II of Figure 1, and
- Figures 3 and 4 illustrate, schematically, the operation of the device of Figures 1 and 2 when analysing positive ions and electrons, respectively.
- a monol thic structure 1 for collecting charged particles comprises a substrate 3 on which is deposited, for example by sputtering, a layer 5 of electrically-conductive material.
- the substrate 3 may be formed of, for example, silicon, and the layer 5 may be, for example, a layer of tungsten of, say, 500 nm thickness.
- the layer 5 is to form a retarding collector electrode, as will be explained later.
- a dielectric layer 7 is then deposited over the layer 5.
- the layer 7 may be formed of, for example, a spin-on silica glass, the number of glass depositions and the spin speed being chosen such that, after baking, the overall thickness of the layer 7 is, for example, approximately 2000 nm.
- a layer of photoresist material (not shown) is then spun on to the layer 13.
- the photoresist is then exposed and developed by conventional techniques to produce an apertured mask for use in subsequent etching of the underlying layers.
- the mask is firstly used for defining apertures which are formed through the layer 13 by wet or dry etching.
- the regions of the glass layer 11 which are thereby exposed are then removed by etching anisotropically, using a dry etching process, such as reactive ion etching, thereby exposing corresponding regions of the conductive layer 9.
- the etching steps are then repeated to remove corresponding regions of the conductive layer 11 and the dielectric layer 7.
- Apertures 15, 17, 19 are thereby formed through the layers 7-13, extending down to the conductive layer 5.
- the remainder of the photoresist layer is then removed.
- the current collection area can be increased by making the apertures 15, 17, 19 elongate trenches as shown in Figure 1. They may be, for example, 1000 nm wide and 5 mm long. However, the apertures may alternatively be of any other required shape. For the sake of clarity of the drawings, only three apertures are shown, but in practice there will be many such apertures distributed over the area of the structure.
- a further layer of photoresist is then deposited over the whole structure, including the apertures, and is exposed and developed to produce an etch mask through which a larger aperture 21 extending down to the layer 9 is subsequently etched, so that a bond pad can be formed on that layer. Further deposition, exposure and development of photoresist are then effected to define a similar aperture 23, which is produced by etching through the glass and tungsten layers as described above. The aperture 23 extends down to the layer 5, so that a bond pad can be formed on that layer. All remaining photoresist material is then removed. A bond pad 25 is provided on the shielding grid layer 13.
- the collector electrode layer may be treated to reduce the rate of emission of secondary electrons or ions and the reflection of incident charges which would otherwise contribute to the collector current.
- the exposed portions of the surface of the collector layer 5 may be coated with graphite, or its surface may be roughened during the construction.
- All of the layers of the monolithic structure should adhere well to each other, and they should preferably have similar coefficients of thermal expansion.
- the particles source is an electrical plasma
- the layers should not be chemically active with species in the plasma, nor should they contaminate the plasma, nor be excessively eroded by it.
- the spacing between the conductive layers 5, 9 and 13, i.e. the thickness of the dielectric layers 7 and 11, should preferably be much larger than the characteristic diameter of the apertures in the layers 9 and 13.
- the spacing should also be smaller than the mean free path of the electrical charges being analysed, over the expected range of operating pressures.
- the dielectric material of the layers 7 and 11 might be replaced by a highly resistive material, such as polycrystalline silicon, which would allow charges incident on the exposed regions to be conducted away. This would prevent an accumulation of surface charge, which could otherwise affect the performance of the device.
- a highly resistive material such as polycrystalline silicon
- the contact pads may be formed before the apertures are defined.
- MOCVD metal organic chemical vapour deposition
- Control and signal processing electronic circuitry for the device may be provided on the substrate 3, preferably before the formation of the apertured layers described above. Electrical connections to the circuitry are then made after the formation of the layers.
- Such an arrangement would provide a better signal-to-noise ratio and reduce the cost of the electronics in applications where the electronics can be located inside the same enclosure (e.g. a plasma reactor) as the monolithic structure.
- a plasma reactor e.g. a plasma reactor
- the device is to be used in a vacuum or low-pressure environment for measuring the energy and direction of movement of charged particles having either positive or negative charge.
- the charged particles may emanate from, for example, an electrical plasma discharge or may be generated in use of ion beam or electron beam apparatus (for example in microscopes).
- an electrical potential is applied to the collector layer 5 such as to retard the approach of charged particles. Only charges with sufficient kinetic energy will be able to surmount this electrical potential barrier and reach the surface of the collector layer. By determining the number of charges which reach the collector layer as a function of the varying retarding potential applied to it, it is possible to deduce the energy distribution of charges incident on the device.
- the optimum size, shape, density and depth of the apertures will depend upon the use to which the device is to be put and the materials used in fabricating the monolithic structure. However, they should preferably be sufficiently small to ensure that the strength of the electrical space-potential does not vary significantly in the plane of the particular grid layer. Hence, they should at least be smaller than the plasma Debye length.
- the rejecting grid layer 9 is set at a potential such as to reject particles of polarity opposite to that of the particles being analysed.
- This potential may, in some cases, be such as to disturb the nature of the plasma, or other particle source, to such an extent that the measurement is invalid. It is in order to protect the source from this potential that the shielding grid layer 13 is provided between the source and the rejecting grid layer.
- the shielding grid layer is preferably set at a potential which is fixed and is negative with respect to the plasma, in which case it will retard a number of the negative charges emanating from the plasma and flowing towards the monolithic structure. If desired, additional aperture shielding grids may be provided.
- Figure 3 illustrates, schematically, the action of the monolithic structure when analysing positive ions emanating from an electrical plasma 27.
- the shielding grid layer 13 which is held at a negative potential with respect to the plasma, rejects some electrons from the plasma, such as indicated by an arrow 29, but tends to return negative charges to the collector electrode layer which might otherwise have escaped from that layer.
- the rejecting grid layer 9 is held at a potential which is very negative relative to the plasma, and rejects more negative charges, as indicated by an arrow 31.
- the collector electrode layer 5 which is at a potential which can be varied with respect to the plasma, rejects or collects positive ions, as indicated by arrows 33 and 35, respectively, depending upon the energy of the ions in relation to the collector potential.
- a measuring instrument 36 is provided to measure the quantity of ions collected.
- Figure 4 illustrates, schematically, the action of the monolithic structure when analysing negative charges emanating from the plasma 27.
- the shielding grid layer 13 which is held at a negative potential with respect to the plasma, rejects some negative charges, as indicated by an arrow 37.
- the rejecting grid layer 9 is held at a potential which is positive with respect to the plasma and rejects positive ions, as indicated by an arrow 39.
- the collector electrode layer 5 is at a negative potential relative to the plasma, which potential can be varied. This layer rejects or collects negative charges, as indicated by arrows 41 and 43, respectively, depending upon the energy of the negative charges in relation to the collector potential.
- a measuring instrument 45 is provided to measure the quantity of electrons collected.
- the monolithic layer structure of the present invention provides a number of advantages over the conventional charged particle analysers. It can measure the energy distribution of charged particles of either polarity. It operates without the use of any additional vacuum pumping equipment beyond that required for the process under investigation (e.g. plasma processing). It can be made at very low cost and in large quantities. It could therefore be used as a disposable device which could be replaced when it became damaged or contaminated or when it required updating. It is so compact that it can be used where space limitations would preclude the use of the conventional analysers. It could be positioned on the surface of an electrode, where the presence of active cooling inside the electrode would preclude the use of a conventional analyser.
- the compact nature of the structure reduces scattering within the structure by background gas molecules and therefore makes it possible to operate over a larger pressure range than those known analysers which do not employ additional vacuum pumping equipment. Due to the apertures in the layers, the monolithic structure restricts the angle of acceptance for incident charged particles and can therefore be made and operated with directional sensitivity. The conventional analysers are not directional unless additional equipment is provided.
- the device could be used in an alternative mode of operation in which a retarding potential is applied to the grid layer 9, and the collector electrode layer 5 is used solely for the- purpose of measuring the quantity of charge received by the layer 5, without itself providing a retarding field.
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- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Plasma & Fusion (AREA)
- Other Investigation Or Analysis Of Materials By Electrical Means (AREA)
Abstract
A device for measuring the energy of charged particles in a low-pressure environment, such as in a plasma processing equipment, comprises a monolithic structure. The structure comprises a collector electrode layer (5) and a rejection electrode layer (9) separated from the collector layer by an insulating layer. Apertures are formed in the rejection and insulating layers to allow charged particles to flow towards the collector layer. The device also includes a voltage source for biasing the collector and rejector layers such that charged particles of a given polarity (29) and having a kinetic energy less than a predetermined level (33) are repelled away from the collector layer, which therefore receives only particles having that polarity and a greater kinetic energy. The quantity of charged particles received by the collector layer is measured.
Description
ENER6Y ANALYSER
This invention relates to an energy analyser for measuring the energy of charged particles which are incident on a planar surface in a low-pressure environment, such as, for example, in a plasma processing equipment.
Conventional apparatuses for measuring the energy of charged particles are formed of a number of interconnected individual units which take up a substantial amount of space, are expensive to manufacture and, more especially, require the provision of pumping equipment which is dedicated to the evacuation of the energy-measuring apparatus.
It is an object of the present invention to provide an improved device for measuring the energy of charged particles.
According to the invention there is provided an energy measuring device comprising a monolithic structure including a planar collector electrode layer and a. rejection electrode layer separated from the collector electrode layer by a first layer of insulating material, said rejection electrode layer and said first layer of insulating material being apertured to allow charged particles from a source of charged particles to flow therethrough towards the collector electrode layer; the device further comprising electrical potential supply means for biasing the collector electrode layer and the rejection electrode layer to
cause charged particles of a given polarity and of kinetic energy less than a predetermined level to be repelled away from the collector electrode layer so that the collector electrode layer receives only particles of said given polarity having a kinetic energy equal to or greater than said level; and means to measure the quantity of charged particles reaching the collector electrode layer.
The collector electrode layer is preferably biased to repel said particles having a kinetic energy less than said predetermined level. The rejection electrode layer is preferably biased to reject charged particles of the opposite polarity.
The monolithic structure may also include an apertured shielding electrode layer separated from the rejection electrode layer by a second layer of insulating material, the shielding electrode layer serving to shield the source of charged particles from the potential applied within the monolithic structure. Further apertured shielding electrode layers may also be provided.
An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in whic :
Figure 1 is a schematic plan view of a monolithic structure for use in the present invention,
Figure 2 is a schematic cross-sectional view taken along a line II-II of Figure 1, and
Figures 3 and 4 illustrate, schematically, the operation of the device of Figures 1 and 2 when analysing positive ions and electrons, respectively.
Referring to Figures 1 and 2 of the drawings, a monol thic structure 1 for collecting charged particles comprises a substrate 3 on which is deposited, for example by sputtering, a layer 5 of electrically-conductive material. The substrate 3 may be formed of, for example, silicon, and the layer 5 may be, for example, a layer of tungsten of, say, 500 nm thickness. The layer 5 is to form a retarding collector electrode, as will be explained later.
A dielectric layer 7 is then deposited over the layer 5. The layer 7 may be formed of, for example, a spin-on silica glass, the number of glass depositions and the spin speed being chosen
such that, after baking, the overall thickness of the layer 7 is, for example, approximately 2000 nm.
A second electrically-conductive layer 9, similar to the layer 5, is formed on the dielectric layer 7 to act as a rejecting grid, followed by a further dielectric layer 11, similar to the layer 7. A third electrically-conductive layer 13, similar to the layers 5 and 9, is then deposited to form a shielding grid.
A layer of photoresist material (not shown) is then spun on to the layer 13. The photoresist is then exposed and developed by conventional techniques to produce an apertured mask for use in subsequent etching of the underlying layers. The mask is firstly used for defining apertures which are formed through the layer 13 by wet or dry etching. The regions of the glass layer 11 which are thereby exposed are then removed by etching anisotropically, using a dry etching process, such as reactive ion etching, thereby exposing corresponding regions of the conductive layer 9. The etching steps are then repeated to remove corresponding regions of the conductive layer 11 and the dielectric layer 7. Apertures 15, 17, 19 are thereby formed through the layers 7-13, extending down to the conductive layer 5. The remainder of the photoresist layer is then removed.
It may be advantageous to effect a subsequent brief isotropic etch in order to etch back selecti ely the edges of the glass layers 7 and 11 in the apertures 15, 17, 19, thereby exposing the edges of the conductive layers 9 and 13 in those apertures.
Although in order to maximise directional resolution of the measurement circular apertures are preferred, the current collection area can be increased by making the apertures 15, 17, 19 elongate trenches as shown in Figure 1. They may be, for example, 1000 nm wide and 5 mm long. However, the apertures may alternatively be of any other required shape. For the sake of clarity of the drawings, only three apertures are shown, but in practice there will be many such apertures distributed over the area of the structure.
A further layer of photoresist is then deposited over the
whole structure, including the apertures, and is exposed and developed to produce an etch mask through which a larger aperture 21 extending down to the layer 9 is subsequently etched, so that a bond pad can be formed on that layer. Further deposition, exposure and development of photoresist are then effected to define a similar aperture 23, which is produced by etching through the glass and tungsten layers as described above. The aperture 23 extends down to the layer 5, so that a bond pad can be formed on that layer. All remaining photoresist material is then removed. A bond pad 25 is provided on the shielding grid layer 13.
The collector electrode layer may be treated to reduce the rate of emission of secondary electrons or ions and the reflection of incident charges which would otherwise contribute to the collector current. For example, the exposed portions of the surface of the collector layer 5 may be coated with graphite, or its surface may be roughened during the construction.
All of the layers of the monolithic structure should adhere well to each other, and they should preferably have similar coefficients of thermal expansion. Where the particle source is an electrical plasma, the layers should not be chemically active with species in the plasma, nor should they contaminate the plasma, nor be excessively eroded by it.
The spacing between the conductive layers 5, 9 and 13, i.e. the thickness of the dielectric layers 7 and 11, should preferably be much larger than the characteristic diameter of the apertures in the layers 9 and 13. The spacing should also be smaller than the mean free path of the electrical charges being analysed, over the expected range of operating pressures.
The dielectric material of the layers 7 and 11 might be replaced by a highly resistive material, such as polycrystalline silicon, which would allow charges incident on the exposed regions to be conducted away. This would prevent an accumulation of surface charge, which could otherwise affect the performance of the
device.
In an alternative method of fabricating the monolithic structure, the contact pads may be formed before the apertures are defined.
In an alternative technique for producing the alternate conductive and non-conductive layers of the structure, metal organic chemical vapour deposition (MOCVD) may be used.
Control and signal processing electronic circuitry for the device may be provided on the substrate 3, preferably before the formation of the apertured layers described above. Electrical connections to the circuitry are then made after the formation of the layers.
Such an arrangement would provide a better signal-to-noise ratio and reduce the cost of the electronics in applications where the electronics can be located inside the same enclosure (e.g. a plasma reactor) as the monolithic structure.
The device is to be used in a vacuum or low-pressure environment for measuring the energy and direction of movement of charged particles having either positive or negative charge. The charged particles may emanate from, for example, an electrical plasma discharge or may be generated in use of ion beam or electron beam apparatus (for example in microscopes).
In use of the device, an electrical potential is applied to the collector layer 5 such as to retard the approach of charged particles. Only charges with sufficient kinetic energy will be able to surmount this electrical potential barrier and reach the surface of the collector layer. By determining the number of charges which reach the collector layer as a function of the varying retarding potential applied to it, it is possible to deduce the energy distribution of charges incident on the device.
In an electrical plasma environment there are charges of positive polarity (i.e. positive ions) and negative polarity (i.e. electrons and/or negative ions), so it is necessary to use the rejecting grid layer 9 to reject charges of the opposite sign to those charges being analysed. For example, if it is desired to
analyse the energy of positive ions, it will be necessary to prevent negative charges from reaching the collector electrode layer, unless their undesirable effect on the current measured at the collector electrode layer can be accurately predicted. There wiTT be a finite number of charges which are intercepted by the rejecting grid layer 9 and the shielding grid layer 13, and which would otherwise reach the collector electrode layer. The grid layers should be designed to minimise this problem by employing a large number of closely-spaced apertures. The optimum size, shape, density and depth of the apertures will depend upon the use to which the device is to be put and the materials used in fabricating the monolithic structure. However, they should preferably be sufficiently small to ensure that the strength of the electrical space-potential does not vary significantly in the plane of the particular grid layer. Hence, they should at least be smaller than the plasma Debye length.
As explained above, the rejecting grid layer 9 is set at a potential such as to reject particles of polarity opposite to that of the particles being analysed. This potential may, in some cases, be such as to disturb the nature of the plasma, or other particle source, to such an extent that the measurement is invalid. It is in order to protect the source from this potential that the shielding grid layer 13 is provided between the source and the rejecting grid layer. The shielding grid layer is preferably set at a potential which is fixed and is negative with respect to the plasma, in which case it will retard a number of the negative charges emanating from the plasma and flowing towards the monolithic structure. If desired, additional aperture shielding grids may be provided.
Figure 3 illustrates, schematically, the action of the monolithic structure when analysing positive ions emanating from an electrical plasma 27. The shielding grid layer 13, which is held at a negative potential with respect to the plasma, rejects some electrons from the plasma, such as indicated by an arrow 29, but tends to return negative charges to the collector electrode layer
which might otherwise have escaped from that layer. The rejecting grid layer 9 is held at a potential which is very negative relative to the plasma, and rejects more negative charges, as indicated by an arrow 31. The collector electrode layer 5, which is at a potential which can be varied with respect to the plasma, rejects or collects positive ions, as indicated by arrows 33 and 35, respectively, depending upon the energy of the ions in relation to the collector potential. A measuring instrument 36 is provided to measure the quantity of ions collected.
Figure 4 illustrates, schematically, the action of the monolithic structure when analysing negative charges emanating from the plasma 27. The shielding grid layer 13, which is held at a negative potential with respect to the plasma, rejects some negative charges, as indicated by an arrow 37. The rejecting grid layer 9 is held at a potential which is positive with respect to the plasma and rejects positive ions, as indicated by an arrow 39. The collector electrode layer 5 is at a negative potential relative to the plasma, which potential can be varied. This layer rejects or collects negative charges, as indicated by arrows 41 and 43, respectively, depending upon the energy of the negative charges in relation to the collector potential. A measuring instrument 45 is provided to measure the quantity of electrons collected.
The monolithic layer structure of the present invention provides a number of advantages over the conventional charged particle analysers. It can measure the energy distribution of charged particles of either polarity. It operates without the use of any additional vacuum pumping equipment beyond that required for the process under investigation (e.g. plasma processing). It can be made at very low cost and in large quantities. It could therefore be used as a disposable device which could be replaced when it became damaged or contaminated or when it required updating. It is so compact that it can be used where space limitations would preclude the use of the conventional analysers. It could be positioned on the surface of an electrode, where the presence of active cooling inside the electrode would preclude the
use of a conventional analyser. The compact nature of the structure reduces scattering within the structure by background gas molecules and therefore makes it possible to operate over a larger pressure range than those known analysers which do not employ additional vacuum pumping equipment. Due to the apertures in the layers, the monolithic structure restricts the angle of acceptance for incident charged particles and can therefore be made and operated with directional sensitivity. The conventional analysers are not directional unless additional equipment is provided.
The device could be used in an alternative mode of operation in which a retarding potential is applied to the grid layer 9, and the collector electrode layer 5 is used solely for the- purpose of measuring the quantity of charge received by the layer 5, without itself providing a retarding field.
Claims
1. An energy measuring device comprising a monolithic structure including a planar collector electrode layer and a rejection electrode layer separated from the collector electrode layer by a first layer of insulating material, said rejection electrode layer and said first layer of insulating material being apertured to allow charged particles from a source of charged particles to flow therethrough towards the collector electrode layer; the device further comprising electrical potential supply means for biasing the collector electrode layer and the rejection electrode layer to cause charged particles of a given polarity and of kinetic energy less than a predetermined level to be repelled away from the collector electrode layer so that the collector electrode layer receives only particles of said given polarity having a kinetic energy equal to or greater than said level; and means to measure the quantity of charged particles reaching the collector electrode layer.
2. A device as claimed in Claim 1, wherein the monolithic structure further comprises a shielding electrode layer separated from the rejection electrode layer by a second layer of insulating material, said shielding electrode layer and said second layer of insulating material being apertured to allow said charged particles to flow therethrough towards the collector electrode layer; and wherein the electrical potential supply means is operative to bias the shielding electrode layer whereby it provides a shield between the rejection electrode layer and the source of charged particles.
3. A device as claimed in Claim 2, wherein the monolithic structure comprises a plurality of said apertured shielding electrode layers spaced from each other.
4. A device as claimed in any preceding claim, wherein the electrode layers are formed of tungsten.
5. A device as claimed in any preceding claim, wherein the insulating material is silica glass.
6. A device as claimed in any preceding claim, wherein the insulating material has a conductance sufficient to conduct away charges formed on the layers.
7. A device as claimed in any preceding claim, wherein at least part of the collector electrode layer is treated to reduce emission of secondary charged particles therefrom.
8. A device as claimed in Claim 7, wherein said at least part of the collector electrode layer is coated with graphite.
9. A device as claimed in Claim 7, wherein the surface of said at least part of the collector electrode layer is roughened.
10. An energy measuring device substantially as hereinbefore described with reference to the accompanying drawings.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9126507A GB2262649B (en) | 1991-12-13 | 1991-12-13 | Energy analyser |
GB9126507.4 | 1991-12-13 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1993012534A1 true WO1993012534A1 (en) | 1993-06-24 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1992/002308 WO1993012534A1 (en) | 1991-12-13 | 1992-12-11 | Energy analyser |
Country Status (2)
Country | Link |
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GB (1) | GB2262649B (en) |
WO (1) | WO1993012534A1 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996016430A1 (en) * | 1993-09-22 | 1996-05-30 | Northrop Grumman Corporation | Solid state micro-machined mass spectrograph universal gas detection sensor |
GB2315362A (en) * | 1996-07-12 | 1998-01-28 | Analytical Precision Ltd | Mass spectrometers |
DE10258118A1 (en) * | 2002-12-06 | 2004-07-08 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device for measuring and determining charge carrier streams and parameters derived from them used in industrial coating devices comprises a sensor formed as a Faraday collector connected to an evaluation and control device |
WO2011151541A2 (en) | 2010-06-03 | 2011-12-08 | Ion Beam Services | Detector for energetic secondary electrons |
CN103003912A (en) * | 2010-06-03 | 2013-03-27 | 离子射线服务公司 | Dose measurement device for plasma-immersion ion implantation |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5492867A (en) * | 1993-09-22 | 1996-02-20 | Westinghouse Elect. Corp. | Method for manufacturing a miniaturized solid state mass spectrograph |
US5451784A (en) * | 1994-10-31 | 1995-09-19 | Applied Materials, Inc. | Composite diagnostic wafer for semiconductor wafer processing systems |
US5633497A (en) * | 1995-11-03 | 1997-05-27 | Varian Associates, Inc. | Surface coating to improve performance of ion trap mass spectrometers |
DE102014110334A1 (en) * | 2014-07-22 | 2016-01-28 | Krohne Messtechnik Gmbh | Method for separating electrically charged particles with respect to their energy and energy filters |
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US3260844A (en) * | 1964-01-31 | 1966-07-12 | Atomic Energy Commission | Calutron with means for reducing low frequency radio frequency signals in an ion beam |
US4246479A (en) * | 1978-02-20 | 1981-01-20 | National Research Development Corporation | Electrostatic energy analysis |
US4608493A (en) * | 1983-05-09 | 1986-08-26 | Sony Corporation | Faraday cup |
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JPS5823705B2 (en) * | 1977-08-24 | 1983-05-17 | 株式会社東芝 | radiation detector |
US4703256A (en) * | 1983-05-09 | 1987-10-27 | Sony Corporation | Faraday cups |
GB8821496D0 (en) * | 1988-09-14 | 1988-10-12 | Univ Manchester | Charged particle multidetector |
GB8914910D0 (en) * | 1989-06-29 | 1989-08-23 | Vg Instr Group | Charge transducer |
-
1991
- 1991-12-13 GB GB9126507A patent/GB2262649B/en not_active Expired - Fee Related
-
1992
- 1992-12-11 WO PCT/GB1992/002308 patent/WO1993012534A1/en active Application Filing
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
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US3260844A (en) * | 1964-01-31 | 1966-07-12 | Atomic Energy Commission | Calutron with means for reducing low frequency radio frequency signals in an ion beam |
US4246479A (en) * | 1978-02-20 | 1981-01-20 | National Research Development Corporation | Electrostatic energy analysis |
US4608493A (en) * | 1983-05-09 | 1986-08-26 | Sony Corporation | Faraday cup |
Non-Patent Citations (1)
Title |
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JOURNAL OF VACUUM SCIENCE AND TECHNOLOGY: PART A. vol. 9, no. 2, April 1991, NEW YORK US pages 364 - 368 P. K. BATTACHARYA ET AL 'A MICRON SCALE FARADAY CUP FOR ELECTRON BEAM CURRENT MEASUREMENTS' * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1996016430A1 (en) * | 1993-09-22 | 1996-05-30 | Northrop Grumman Corporation | Solid state micro-machined mass spectrograph universal gas detection sensor |
GB2315362A (en) * | 1996-07-12 | 1998-01-28 | Analytical Precision Ltd | Mass spectrometers |
DE10258118A1 (en) * | 2002-12-06 | 2004-07-08 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Device for measuring and determining charge carrier streams and parameters derived from them used in industrial coating devices comprises a sensor formed as a Faraday collector connected to an evaluation and control device |
WO2011151541A2 (en) | 2010-06-03 | 2011-12-08 | Ion Beam Services | Detector for energetic secondary electrons |
CN103003912A (en) * | 2010-06-03 | 2013-03-27 | 离子射线服务公司 | Dose measurement device for plasma-immersion ion implantation |
CN103003911A (en) * | 2010-06-03 | 2013-03-27 | 离子射线服务公司 | Detector for energetic secondary electrons |
CN103003912B (en) * | 2010-06-03 | 2016-01-13 | 离子射线服务公司 | For the dose measurement device of plasma immersion and ion implantation |
Also Published As
Publication number | Publication date |
---|---|
GB2262649B (en) | 1995-03-01 |
GB9126507D0 (en) | 1992-02-12 |
GB2262649A (en) | 1993-06-23 |
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