WO2019046689A1

WO2019046689A1 - Apparatus and method for real-time non-invasive composition sensing and imaging

Info

Publication number: WO2019046689A1
Application number: PCT/US2018/049037
Authority: WO
Inventors: Jeremy William TOLE; Peter Walther; Aryan TAHERI
Original assignee: Azbil North America Research and Development, Inc.
Priority date: 2017-09-01
Filing date: 2018-08-31
Publication date: 2019-03-07
Also published as: TW201915474A

Abstract

An apparatus and method for noninvasively sensing the identities and spatial arrangement of molecular or atomic components in a composition in a closed or open environment. One or more arrays of emitters emit electromagnetic radiation in one or more bands of the terahertz or mmWave frequency spectrum into the closed or open environment, and one or more arrays of receivers receive unabsorbed radiation after it has passed through the environment. A controller (e.g., an amplifier/converter) determines the identities and spatial arrangement of the composition components by comparing the received radiation to known spectral signatures. This determination may be used to generate a 3-D image of the environment, which may be recorded and tracked to detect environmental changes over time. Changes to the composition within the environment may be made in response to the identified components and/or their spatial arrangement. The method may be performed in real time.

Description

APPARATUS AND METHOD FOR REAL-TIME

NON-INVASIVE COMPOSITION SENSING AND IMAGING

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. provisional application Ser. No. 62/553,212, filed September 1 , 2017, which is incorporated herein by reference as if fully set forth herein.

FIELD OF THE INVENTION

[0002] The present invention relates to an improved method and apparatus for real-time non-invasive composition sensing and imaging of a closed or open environment, such as the composition sensing of gases in semiconductor processing within a chamber and imaging/mapping of the gases in the chamber.

BACKGROUND OF THE INVENTION

[0003] Process automation, such as fabrication of semiconductors, and composition processing is best conducted in a controlled environment. For example, semiconductor processing is best conducted in a chamber, i.e., a closed environment, that contains a specific mixture of gases that is optimized for the process to be performed. Some of these gases are desirable in specific quantities for particular processes or steps thereof while other gases may be emitted that are not desirable at all or are best maintained below a specific threshold during the processes or steps thereof.

[0004| An example of a process in which the mixture of gas composition should be measured and controlled is the plasma etching process for semiconductor fabrication. Plasma etching includes processes such as sidewall-inhibitor deposition, ion enhanced etching, physical etching, chemical etching. During these processes, which are described, for example, with respect to Figures 10-20, 10-7, and 10-9 of a treatise entitled Silicon VLSI Technology: Fundamentals, Practice, and Modeling, 1st Edition, by James D. Plummer, Michael Deal, and Peter D. Griffin (2000), various gases are input for plasma etching via an inlet (e.g., Ar, CF₄, and 0₂) into a chamber in which the etching takes place and gases must also be removed via a gas outlet pump as a result of the reactions that take place (e.g., conversion to a plasma) during etching (e.g., disassociation, dissociative ionization, ionization, excitation, and recombination).

[0005] More generally, conventional composition processing applications use mass flow controllers that accurately detect and control the flow rate for the inflow and outflow into a chamber of a composition and a mixture sensor. However, the conventional apparatuses and methods are not sufficiently accurate and reliable to detect and control reactions and mixtures in a manner that results in a desired high yield of semiconductor products without significant manufacturing defects.

[0006] Spectroscopy is the interaction between matter and electromagnetic radiation and it is a method of analysis mat can identify the molecular contents of a sample that is either a solid, liquid, or gas form of any atom, molecule, crystal lattice, or nuclei. Spectroscopy achieves this through the interaction of electromagnetic radiation with atoms and molecules. The effect of the electromagnetic radiation on the atoms and molecules depends on mainly the frequency of electromagnetic radiation emitted. There is a wide range of different types of spectroscopy due to the varying frequencies of emitted that include and are not limited to X-ray spectroscopy, ultraviolet spectroscopy, infrared spectroscopy, visible light spectroscopy, nuclear magnetic resonance, and microwave spectroscopy.

|0007| These forms of spectroscopy take advantage of the energy absorption and emission qualities of atoms and molecules in order to identify atoms and molecules. Absorption of electromagnetic radiation by atoms and molecules can be described as the energy of photons taken up by the atoms and molecules when in contact with electromagnetic radiation. When utilizing spectroscopy, one can infer the identity of a molecule or atom through analyzing which frequencies of electromagnetic radiation are absorbed by the atoms and molecules. Depending on the presence of certain functional groups in molecules or the size of the atoms being analyzed, electromagnetic radiation will be absorbed in its entirety, partially, or not at all. Functional groups are groups of atoms present in molecules that give the molecule chemical functionality. One example of a functional group is a ketone, which is an oxygen atom double bonded to a carbon atom. When using IR spectroscopy to analyze a molecule, if there is presence of strong absorption around frequencies of 1700-1750 cm^'1, it can be inferred that there is presence of a carbon with a double bond to an oxygen in the sample being analyzed by the electromagnetic radiation. The presence of absorption at certain frequencies that identifies functional groups or atoms within a sample is called a signature.

(0008] Generally, all forms of spectroscopy sweep frequencies, which is emitting a range of frequencies of electromagnetic radiation, in order to identify the signatures of absorption which will ultimately serve the purpose of identifying the sample in spectroscopy. Depending on the type of spectroscopy being used, the range of frequencies being swept will vary. Generally, it is contained within the range of the electromagnetic spectrum specified by the form of spectroscopy. For example, infrared spectroscopy will sweep for frequencies of electromagnetic radiation contained within the infrared range of the electromagnetic spectrum, while ultraviolet spectroscopy will sweep for frequencies within the ultraviolet section of the electromagnetic spectrum. The effect of the electromagnetic radiation on the molecule or atom in the sample depends on the range of frequencies being emitted. In other words, microwave radiation, ultraviolet radiation, and infrared radiation have different effects on the atoms, molecules, and bonds between atoms in molecules.

[0009] For example, the infrared frequencies of electromagnetic radiation have a unique effect on the bonds between atoms in molecules. When infrared radiation comes into contact with molecules, the bonds between the atoms in molecules increase in energy and display particular movements ranging from rocking to vibrating. Vibrational spectroscopy is a method of analyzing molecules based on their vibrational energy resulting from the absorption of electromagnetic radiation. Infrared spectroscopy is one of the forms of spectroscopy that utilizes analysis through vibrational spectroscopy.

|0010] Bonds between atoms are modeled generally as springs instead of rigid lines connecting atoms. The spring model serves as an accurate representation because the bonds between atoms can be stretched or bent - they do not remain in place. The different movement types that bonds experience include the following: stretching, scissoring, rocking, and wagging. However, bond movement is not limited to the aforementioned movements. The varying types of movements are induced by energy, and the change between the different types of movements are quantized. Each movement is assigned a quantum energy level. Temperature is one factor that can induce quantum energy level transitions by exciting bonds. However, infrared spectroscopy uses high frequency electromagnetic radiation to induce quantum energy transitions in bonds. The excitement of the bonds by electromagnetic radiation, in turn, results in different types of bond movements.

[0011] Chemical bonds are the interactions between atoms resulting from the sharing of electrons or electrostatic forces. There are multiple types of bonds that form between atoms and those are the following but are not limited to: single covalent bonds, double covalent bonds, triple covalent bonds, polar covalent bonds, ionic bonds, lattices composed of covalent bonds, lattices composed of covalent and ionic bonds, and lattices composed of ionic bonds. There are also loose bonds such as hydrogen bonds that also form between atoms with polar bonds and hydrogen atoms.

[0012] Covalent bonds are very common bonds that are generally interactions in which electrons are shared between atoms in molecules. There are some instances in which sharing is unequal, which is called polar covalent bonds. In a polar covalent bond, one atom is more electronegative, meaning that it attracts electrons more so than the other atom it is sharing electrons with. As a result of having higher electronegativity, the electrons will surround that atom more so than the other atom in the polar bond resulting in a partially positive atom and a partially negative atom. The more electronegative atom is the partially negative side. Polar bonding is a strong interaction that is stronger than a covalent bond with equal sharing. Furthermore, covalent bonds can be present in single, double, and triple bonds. A single covalent bond is an interaction in which two electrons are being shared, one from one atom in the bond and another electron from the other atom in the bond. Double covalent bonds are two single covalent bonds formed between two different atoms. In the case of the double covalent bond, four electrons are being shared in total.

Triple covalent bonds are three single covalent bonds formed between two different atoms, and in that case, six electrons are being shared in total. Double bonds are more rigid than single bonds and are higher in energy. They have a higher dissociation, which is defined as the energy required to break the chemical bond and separate the atoms. Additionally, their movements are more restricted than single covalent bonds because they are composed of both sigma and pi bonds. Triple bonds have an even higher dissociation energy than double bonds and are therefore a stronger attraction between two atoms. As a result, the bond movement is even more restricted than double bonds, and triple bonds are composed of one sigma bond and two pi bonds. A sigma bond is analogous to a single covalent bond. It is a bond that is formed from a head on overlap of electron orbitals in the space directly between the nuclei of atoms. Sigma bonds are the strongest form of covalent bonding. Double bonds include both the sigma bond that single covalent bonds are composed of along with pi bonds. Pi bonds are a form of covalent bond that is formed in a side by side fashion.

They are not as strong as sigma bonds, but sigma bonding supplemented by pi bonding results in a stronger interaction between two atoms. Triple bonds have two side by side overlaps in addition to the sigma bond making them the strongest interaction between covalently bonded atoms. The comparative strengths are the following: double bonded atoms have an interaction that is twice as strong as single bonded atoms and triple bonded atoms have an interaction that is three times as strong as single bonded atoms.

[0013] As a result of covalent bonds having different bond strengths resulting from being polar covalent, single, double, or triple bonds, different levels of electromagnetic frequencies will induce quantized movements in the bonds. Different movements in bonds are easier to induce than others. For example, stretching requires less energy to induce than bending does. The required frequency to induce stretching is modeled by the following equation:

1. V = frequency of electromagnetic radiation.

2. M 1 = mass of the first atom in the bond.

3. M2 = mass of the second atom in the bond.

4. F = force constant associated with the type of bond. F is different for single double and triple bonds.

5. C = speed of light constant.

The force constant f is associated with spring stiffness resulting from the type of bond. Double bonds are higher in energy than single bonds and are stiffer as a result. As a result, the force constant for double bonds is higher than the force constant for single bonds. Triple bonds are the strongest interaction, so they are the stiffest and have the highest force constant. Furthermore, as shown by the equation, the masses of atoms in the bond have an effect on the frequency of electromagnetic radiation that induces bond stretching. When one atom has significantly more mass than the other atom, then the frequency required to induce stretching is higher than the case in which both atoms in the bond are of similar masses.

[0014| In vibrational spectroscopy, which is used in infrared spectroscopy, when a frequency of electromagnetic radiation comes into contact with a bond that is equal to the frequency determined by the previous equation, the bond will absorb that energy and display stretching movement. The frequency absorbed by the bond is a chemical signature that is used to identify the bond. For example, an oxygen and hydrogen bond will have a unique stretching frequency that is different from the stretching frequency of a nitrogen and hydrogen bond. The combination of signatures of absorption present when a sweeping electromagnetic frequency comes in contact with a sample will determine the identity of the sample. The identity of the sample is based on the presence of certain signatures and the lack of others. By identifying a present functional group, the identity of the sample can be pieced together.

[0015] Rotational spectroscopy is another important example of analysis that is related to terahertz spectroscopy and microwave spectroscopy. Rotational spectroscopy is related to the quantized rotational movement states of gas molecules as opposed to the quantized vibrational movement states that vibrational spectroscopy analyzes.

[0016] Rotational and vibrational spectroscopy are similar in many ways, such as they both deal with quantized bond movement states, but there are also many differences. Generally, rotational spectroscopy serves as a form of analysis for polar gas molecules. Polar gas molecules display signatures for quantized rotational movements while non polar molecules do not. Rotational spectroscopy is a form of spectroscopy that utilizes electromagnetic frequencies that are lower than the ones used for vibrational spectroscopy. Specifically, vibrational spectroscopy implements the infrared region of the electromagnetic which is defined as the range of frequencies between 430

THz down to 300 GHz, while rotational spectroscopy implements the terahertz or microwave regions of the electromagnetic spectrum. The terahertz region is also identified as the far infrared range of the electromagnetic spectrum and encompasses the frequency range of 300 GHz to 3 THz. The microwave region of the electromagnetic spectrum is the frequency range of 300 MHz to 300 GHz.

[0017] There is some overlap between the terahertz and infrared regions of the

electromagnetic spectrum, but terahertz encompasses a frequency range of lower frequencies than the infrared portion of the electromagnetic spectrum. As a result, rotational spectroscopy exposes the molecules to lower energy electromagnetic radiation than vibrational spectroscopy. This lower energy electromagnetic radiation results in a different type of analysis. For example, in vibrational spectroscopy, one analyzes different sized absorption peaks at different frequencies to identify functional groups that were contained in the molecule. But, in rotational spectroscopy, one observes the rotational state for the entire molecule instead of observing the absorption for each individual bond in the molecule.

[0018] Aside from having a closer relationship to rotational spectroscopy instead of vibrational spectroscopy, terahertz spectroscopy is also capable of providing more information about the molecules being analyzed in comparison to infrared spectroscopy. Terahertz spectroscopy is able to get more information on the electromagnetic radiation than infrared spectroscopy can on the radiation. Terahertz spectroscopy is able to receive information on the amplitude and phase of the emitted radiation, while infrared spectroscopy is only able to receive information about the amplitude of emitted radiation. The resulting effect is that terahertz spectroscopy measures the electrical field of pulses of terahertz radiation instead of just being a power measurement which is what infrared spectroscopy accomplishes. By measuring only power, infrared spectroscopy can only measure the transmittance of photons. In order for infrared spectroscopy to receive information on the electrical field of emitted electromagnetic radiation, a Kramers-Kronig analysis, which is a method of connecting real and imaginary parts of functions, needs to be implemented, but is rather difficult to accomplish because information on the molecules being analyzed needs to be obtained for every frequency of electromagnetic radiation emitted. Overall, terahertz spectroscopy serves as a method of analysis that can provide more direct information about the emitted electromagnetic pulse than infrared spectroscopy.

|0019] While a spectroscope can identify molecules by coming into contact with a sample of a solid, liquid, or a gas, a spectroscope does not analyze particles in a composition in a given space noninvasively.

SUMMARY

[0020] The present invention provides an apparatus and method that detects (senses) and measures a gas, liquid, solid, and / or plasma composition to identify the particles / components of the composition and the spatial arrangements of the solid, gas, liquid, and/or plasma particles (molecules or atoms) in the composition in a closed environment or in an open environment in an accurate, reliable, and repeatable way in a plurality of applications requiring non-invasive and realtime capability with a flexible and re-configurable scheme. The identities of the components in the composition and the spatial arrangement of the components of the environment that has been sensed may be graphically displayed as 2-D or 3-D images for a user to understand the spatial arrangement of the particles in the composition.

[0021] In an exemplary embodiment of the present invention, an apparatus for non-invasive detection and imaging of molecular or atomic components in a composition, having at least one of a gas, a liquid, a plasma, or a solid, in a chamber (closed environment) includes (a) one or more emitters that are configured to emit electromagnetic radiation having a spectrum of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and are positioned to direct the emitted electromagnetic radiation from outside the chamber into the chamber through a first window on the chamber, wherein the first window includes at least one transparent or

semi transparent section on the chamber, such that the electromagnetic radiation that is emitted by the one or more emitters is transmitted into the chamber through the first window and passes through the chamber; (b) one or more receivers that are positioned and configured to receive a signal having the electromagnetic radiation that remains after any absorption by the composition in the chamber of the emitted electromagnetic radiation, and to detect, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters; and (c) one or more controllers, operatively connected to the one or more emitters and the one or more receivers, wherein the one or more controllers are programmed to (i) obtain the signal received by the one or more receivers, (ii) compare the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum, (iii) determine the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the chamber with reference to the database of predetermined spectral signatures, and (iv) generate an image of the chamber and the one or more molecular or atomic components in the chamber based on the determined identities and the spatial arrangement.

[0022] In embodiments, the one or more emitters may include a heterodyne array of emitters and the one or more receivers include a heterodyne array of receivers.

[0023] In embodiments, die one or more controllers are further programmed to generate the image of the one or more molecular or atomic components in 3-D based on the spatial arrangement of the composition in the chamber. 100241 In exemplary embodiments, the one or more emitters and the one or more receivers are positioned outside of the first window, the chamber has an interior reflective surface opposite the one or more receivers to reflect the electromagnetic radiation that passes through the chamber, and the one or more receivers receive the electromagnetic radiation that is reflected from the interior reflective surface back to the one or more receivers. In embodiments, the apparatus further includes a parabolic mirror positioned between the one or more emitters and the first window to capture the electromagnetic radiation emitted by the one or more emitters and direct the electromagnetic radiation through the first window.

|0025] In other exemplary embodiments, the one or more receivers are positioned outside of a second window in the chamber and substantially opposite the one or more emitters, wherein the second window has at least a second transparent or semi transparent section of the chamber to receive the electromagnetic radiation after it has passed through the chamber.

[0026] In embodiments, the one or more controllers are further programmed to transmit a second signal to regulate an inflow and an outflow of one or more particles in the chamber based on the determination of the identities and the spatial arrangement of the one or more molecular or atomic components in the composition within the chamber. In embodiments, the chamber is for plasma etching of semiconductors, and the regulation of the inflow and the outflow allows for an automated adjustment of at least one of an amount, mixture, or location of the molecular or atomic components in the chamber during the plasma etching.

[0027] In embodiments, the one or more controllers are further programmed to track the identities and the spatial arrangement of the composition in the chamber over time. In

embodiments, the one or more controllers are further programmed to measure an amount of the molecular or atomic components identified in the composition. |0028| In another exemplary embodiment of the present invention, an apparatus for noninvasive detection and imaging of molecular or atomic components in a composition, including at least one of a gas, a liquid, a plasma, or a solid, in an open environment, includes: (a) one or more emitters that are configured to electromagnetic radiation having a spectrum of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and are positioned to direct the emitted electromagnetic radiation through a segment of the open environment; (b) one or more receivers that are positioned and configured to receive a signal including the electromagnetic radiation that remains after any absorption by the composition in the segment of the open environment of the emitted electromagnetic radiation, and to detect, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters; and (c) one or more controllers, operatively connected to the one or more emitters and the one or more receivers, wherein the one or more controllers are programmed to (i) obtain the signal received by the one or more receivers, (ii) compare the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum, (iii) determine the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the open environment with reference to the database of predetermined spectral signatures, and (iv) generate an image of the segment of the open environment and the one or more molecular or atomic components in the segment of the open environment based on the determined identities and the spatial arrangement.

[0029] In embodiments, die controller is further programmed to generate the image of the one or more molecular or atomic components in 3-D.

[0030] In embodiments, the controller is further programmed to track the identities and the spatial arrangement of the composition in the segment of the open environment over time. |00311 In embodiments, the one or more emitters include a heterodyne array of emitters and the one or more receivers include a heterodyne array of receivers.

[0032| In embodiments, the one or more emitters are laser emitters. In embodiments, the one or more emitters are high frequency diodes.

[0033] In another exemplary embodiment of the present invention, a method for noninvasive detection and imaging of molecular or atomic components in a composition, including at least one of a gas, a liquid, a plasma, or a solid, in a chamber, includes: (a) emitting, by one or more emitters, electromagnetic radiation having a spectrum of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and directing the emitted electromagnetic radiation from outside the chamber into the chamber through a first window on the chamber, wherein the first window includes at least one transparent or semitransparent section on the chamber, such that the electromagnetic radiation that is emitted by the one or more emitters is transmitted into the chamber through the first window and passes through the chamber; (b) receiving, by one or more receivers, a signal including the electromagnetic radiation that remains after any absorption by the composition in the chamber of the emitted electromagnetic radiation, and detecting, in the received

electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters; (c) obtaining, by one or more controllers operatively connected to the one or more emitters and the one or more receivers, the signal received by the one or more receivers; (d) comparing, by the one or more controllers, the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum; (e) detennining, by the one or more controllers, the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the chamber with reference to the database of predetermined spectral signatures; and (f) generating, by die one or more controllers, an image of the chamber and the one or more molecular or atomic components based on the determined identities and the spatial arrangement.

[0034| In embodiments, the chamber has an interior reflective surface opposite the one or more receivers to reflect the electromagnetic radiation that passes through the chamber, and the step of receiving, by the one or more receivers, of the signal includes receiving electromagnetic radiation that is reflected from the interior reflective surface back to the one or more receivers.

[0035] In embodiments, a parabolic mirror is positioned between the one or more emitters and the first window, and the step of directing the emitted electromagnetic radiation from outside the chamber into the chamber includes directing the electromagnetic radiation toward the parabolic mirror such that it is reflected from the parabolic mirror through the first window into the chamber. |0036| In embodiments, the one or more receivers are configured to be positioned outside of a second window in the chamber and substantially opposite the one or more emitters, and wherein the step of receiving, by the one or more receivers, of the signal includes receiving electromagnetic radiation that passes out of the second window of the chamber after it has passed through the chamber.

[0037] In embodiments, the step of generating, by the one or more controllers, the image of the one or more molecular or atomic components includes generating the image in 3-D.

[0038] In embodiments, the method further includes: transmitting, by the one or more controllers, a second signal to regulate an inflow and an outflow of one or more particles in the chamber based on the determination of the identities and the spatial arrangement of the one or more molecular or atomic components in the composition within the chamber.

[0039] In embodiments, the method further includes tracking, by the one or more controllers, the identities and the spatial arrangement of the composition in the chamber over time. 100401 In embodiments, the method further includes measuring an amount of the molecular or atomic components identified in the composition.

[0041| In embodiments, steps (b) to (f) are performed in real-time.

|0042] In another exemplary embodiment of the present invention, a method for noninvasive detection and imaging of molecular or atomic components in a composition, having at least one of a gas, a liquid, a plasma, or a solid, in an open environment, includes: (a) emitting, by one or more emitters, electromagnetic radiation having a spectrum of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and directing the emitted electromagnetic radiation into a segment of the open environment; (b) receiving, by one or more receivers, a signal including the electromagnetic radiation that remains after any absorption by the composition, in the segment of the open environment, of the emitted electromagnetic radiation, and detecting, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters; (c) obtaining, by one or more controllers operatively connected to the one or more emitters and the one or more receivers, the signal received by the one or more receivers; (d) comparing, by the one or more controllers, the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum; (e) determining, by the one or more controllers, the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the chamber with reference to the database of predetermined spectral signatures; and (f) generating, by the one or more controllers, an image of the segment of the open environment and the one or more molecular or atomic components in the segment of the open environment based on the determined identities and the spatial arrangement. In embodiments, steps (b) to (f) are performed in real-time. BRIEF DESCRIPTION OF THE DRAWINGS

[0043J Exemplary embodiments of the present invention will be described with reference to the accompanying figures, wherein:

[0044] FIG. 1 illustrates an embodiment of a non-invasive composition sensing apparatus having a dual port connection to a chamber (enclosure), which may be a plasma etch chamber, in accordance with an embodiment of the present invention;

[0045] FIG. 2 illustrates a non-invasive composition sensing apparatus having a single port connection to a chamber in accordance with another embodiment of the present invention;

[0046] FIG. 3 shows a graph that illustrates the vacuum normalized data that has been obtained for the composition in die chamber and may be used to identify die molecules and atoms present in the chamber in accordance with an embodiment of the present invention;

[0047] FIG. 4 illustrates a non-invasive composition sensing apparatus having a parabolic mirror in accordance with another embodiment of the present invention;

[0048] FIG. 5 illustrates the error corrected reflection of electromagnetic radiation collected from emitting 500-750 GHz frequency radiation using the apparatus of FIG.4 in accordance with an exemplary embodiment of the present invention;

|0049| FIG. 6 illustrates a non-invasive composition sensing apparatus in accordance with another embodiment of the present invention where the apparatus includes multiple windows for arrays of emitters and receivers and composition sensing;

[0050] FIG. 7 illustrates an example of an imaging array that may implemented in the embodiment of FIG. 6 or other embodiments of the present invention; |00511 FIG. 8 illustrates an example of imaging / mapping a spatial arrangement of molecules that have been detected in a three dimensional space in accordance with an embodiment of the present invention; and

|0052] FIG. 9 illustrates a non-invasive composition sensing apparatus that operates in an open environment in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0053] The present invention provides an apparatus (device) and method with the capability to detect (sense) and measure the composition of at least one of gases, liquids, solids or plasmas within an open environment or in a closed environment, such as a chamber / enclosure. In particular, the present invention is configured to detect objects on the scale of molecules and compounds within an open or closed environment where the environment is in the range of an extremely small environment up to an environment that is the size of a large room (e.g., 25,000 sq. ft.). As used herein, an open environment refers to an environment that is not fully enclosed.

[0054] The apparatus and method also provides for the capture of an image of the inside of the chamber in an accurate, reliable, and repeatable way in one or more applications. The chamber / enclosure may be, for example, an enclosed vessel, container, or other closed environment. In embodiments, the apparatus and method operate in a non-invasive manner and have a real-time capability. Additionally, in embodiments, the apparatus and method of the present invention are configured for detection of the composition in a flexible and re-configurable scheme.

[0055] In embodiments, the apparatus, which may be used, for example, to measure gases and may include one or more sensors that detect the composition, such as the composition of gases in a mixture, including the gas species in the mixture, the temperature of the mixture, and captures an image displaying the spatial arrangement of gas particles within a chamber in which the gases are contained, and one or more other additional properties of the gases in the chamber or vessel such that one or more of the composition of the gases, and one or more of these other properties may be adjusted, such as with a controller that receives the detected values.

[0056] The noninvasive composition sensor(s) may also have temperature measurement qualities so that no separate thermal sensor would be required to measure the temperature of the gases. For example, the frequency of electromagnetic radiation that the current experimental model operates within, the terahertz region, has temperature sensing qualities similar to infrared cameras so that no separate thermal sensor is necessary. This allows temperature to be measured, such as to an accuracy of one degree Celsius with a range spanning from 100 to 400 degrees Celsius.

[0057] The one or more additional properties mat may be detected, measured and /or controlled include one or more of the following:

• Plasma Density

• Anisotropy

• Plasma Energy

• Pressure

• Etching Rate

• Molecular Density of the Gas Particles

• Particle Detection

• Gas Emission Spectrum

• Spatial Imaging of Particles

• High Resolution Imaging of Environment These properties could be measured through the addition of sensors, which may, in embodiments, be added to the emitters or receivers, such as the emitters / receivers described below in the various embodiments, to measure additional properties / qualities of particles in the environment.

[0058] In embodiments, one or more of the sensors include an emitter and a receiver. In an exemplary embodiment, the one or more sensors operate in real-time. In embodiments, the one or more sensors should be non-destructible by the composition that they are being used to measure. In embodiments, the one or more sensors should be non-destructive to and not alter the material / matter that they are measuring.

|0059] The apparatus further includes a controller, which may be or may include an amplifier/converter, that receives the detected values for possible manual and/or automatic adjustment of the composition based on one or more measured properties. In embodiments, the controller that corresponds to or includes the amplifier/converter or a second controller may be implemented to turn the apparatus on or off.

[0060] The apparatus may further include additional hardware, software, and/or circuitry that operate in conjunction with the one or more sensors to detect the compositions of materials and/or matter during semiconductor or composition processing and allow for noninvasive, real time imaging of the space in which the matter and/or materials desired to be detected are contained.

[0061] In embodiments of this invention, the apparatus is configured to detect the composition of the solids, liquids, gases, or plasmas that are contained within a space, while simultaneously capturing images of the space over time such that the interactions of particles within the space and changes of the solid, liquid, gas or plasma particles during a period of time may be tracked. In embodiments, the images are taken in real time and are time stamped and recorded. The space may be a space in a closed environment, like a chamber, or a space in an open environment. |0062| Some example of applications / uses in which an apparatus and method in accordance with an exemplary embodiment of the present invention may be implemented, to name a few, are:

• Plasma Etching for Semiconductor Processing

• Factory Emissions

• Process Gas

• Agriculture Gas

• Solid, liquid, gas, and plasma composition Detection.

100631 For example, in embodiments, the apparatus may be utilized to detect compositions within chambers to detect gas particles in plasma etch chambers. It is beneficial to know the exact location of gas and plasma molecules during the etching process in order to accurately determine the etching end point and to use mat information to execute better control of the plasma etch environment. With time stamped images displaying the spatial arrangement of molecules in real time, uniform etching of the silicon wafer can be performed with a better accuracy due to better control. Thus, where the detection of the composition detects gases, the apparatus identifies particular gases and measures the amount of and/or ratios of these gases within a chamber during semiconductor processing. In addition, the detection and measurement of the composition of the gases at any point within a given area that includes the gases, such as within a chamber, allows for 2-D or 3-D mapping that displays the spatial arrangement of particles in the chamber within a portion of or an entire area of interest.

[0064] A method in accordance with an exemplary embodiment of the present invention includes detecting the composition of gases in a mixture, including the gas species in the mixture, the temperature of the mixture, and the one or more other additional properties of the gases in the chamber, as described above while capturing an image of the space in which the gas mixture is contained within.

[0065| In embodiments, the apparatus and method determines the composition of at least one of gases, solids, liquids, or plasmas in an accurate, reliable, and repeatable way in one or more applications that require non-invasive and real-time capability with a flexible and re-configurable scheme, while capturing an image of the space in which the gases, liquids, solids, or plasmas are contained within in real time.

[0066] In embodiments, the apparatus and method is further configured for at least one of the following:

• High temperature and/or harsh environment operation.

• Use of Very High Frequency Technology, such as THz/FIR/mmWave

Technology for Material Sensing emitters and receivers (terahertz diode or Far- infrared diode is a diode with output wavelength in between 30-1000 μιη (frequency 0.3-10 THz) in the far infrared or terahertz frequency band of the electromagnetic spectrum; Millimeter wave spectrum is the spectrum between 30 GHz and 300 GHz.)

• Indoor/Outdoor Operation.

• High or Low Pressure Operation.

• Detect/Differentiate between composition species.

• Detect Foreign Particles.

[0067] In embodiments, the detection of the composition of gases includes the identification of the gases and the measurement measures the amount of and/or ratios of these gases within a chamber during semiconductor processing. In embodiments, the apparatus includes components that are configured to detect and measure the composition of the gases at any point within a given area that includes the gases, such as within a chamber, to allow for a 2-D and/or 3-D mapping of the spatial arrangements of particles within a portion of or an entire area of interest. A 2-D mapping shows the composition in a slice of the chamber while a 3-D mapping shows the composition in the entire chamber. The sensors may be located on the exterior of the chamber so as to be non-invasive and may be movable up and down on the exterior of the chamber and / or scan to perform the 2-D and/or 3-D mapping.

[0068] A method in accordance with an exemplary embodiment of the present invention includes capturing an image of the spatial arrangement of molecules in a given space, detecting the composition of gases in a mixture, including the gas species in the mixture, the temperature of the mixture, and the one or more other additional properties of the gases in the chamber, as described above.

[0069] In embodiments, the apparatus detects the composition of the solids, liquids, gases, plasmas, or any matter contained within a space, while simultaneously capturing images of the space. The images serve the function of having a greater understanding of the interactions of particles within the space and allows for enhanced tracking of changes the solid, liquid, and gas particles undergo during a period of time. In embodiments, the images are taken in real time and are time stamped and recorded.

[0070] As an example, the apparatus may be utilized to detect gas particles in plasma etch chambers. Plasma etch processing is performed inside of a closed environment that contains a particular ratio of gas and plasma particles in order to as successfully as possible complete the process. To maintain as close as possible to an ideal ratio of gas and plasma particles inside the closed environment in which plasma etch processing is performed, the gas and plasma particles in the closed environment are identified and monitored, the temperature of the closed environment may be monitored, and a 2-D or 3-D map of the closed environment created. These gas and plasma particles that can be present inside the closed environment can be of a wide variety of particles that can be monoatomic, diatomic, ions, radicals, or molecules containing the following different types of chemical bonds:

• Ionic

• Covalent

• Polar Covalent

• Nonpolar Covalent

|0071| It is also beneficial to know the exact location of gas and plasma molecules during the etching process in order to accurately determine the etching end point and to use that information to execute better control of the plasma etch environment. With time stamped images displaying the spatial arrangement of molecules in real time, uniform etching of the silicon wafer can be performed with a better accuracy due to better control. More generally, the present invention may be used to detect the changing composition in a chamber during chemical reactions.

[0072] In another exemplary embodiment of the present invention, an apparatus and method includes components that are configured to detect and measure the composition of at least one of the gases, liquids, solids, or plasmas at any point within a given area that includes the composition, such as within a chamber, to allow for a 2-D and/or 3-D mapping displaying the spatial arrangement of particles within a portion of or an entire area of interest.

[0073] Thus, mere is a need to monitor the content of the space contained in a closed environment or an open environment (e.g., a segment of the open environment) by determining the composition of all matter contained in the closed environment while also monitoring the spatial arrangement of the particles. Furthermore, it is desirable to be able to visually represent, either in 2-

D or 3-D format through imaging, the contents of the closed or open environment including the spatial arrangement of particles within the closed or open environment. Additionally, it is desirable, in embodiments, to be able to measure the temperature in a closed or open environment while measuring the composition of the matter contained in a closed or open environment. Finally, it is desirable to accomplish the previously mentioned tasks in real time and on all phases of matter including, but not limited to, solid, liquids and gas.

|00741 To capture an image of the spatial arrangement of the particles inside of the chamber, an array or multiple arrays of heterodyne emitters and receivers may be implemented. An emitter emits radiation through a window on the outside of the chamber, and outside of that same window or a different window on the outside of apparatus 10 may be an array of heterodyne receivers.

Through the emission of electromagnetic radiation from the array(s) of emitters and receipt by the array(s) of receivers, real time imaging of the spatial arrangement of the molecules can be obtained, adding the final essential component to the non-invasive composition sensor. The electromagnetic radiation emitted excites the electrons of the particle it comes in contact with, causing the electron to jump an energy level. The charge of the particle is men recorded and an image of the particle with which the radiation interacted may be produced.

[0075] An example of an embodiment of me composition sensing quality of die noninvasive composition sensor uses a noninvasive composition sensor utilizing terahertz radiation as a medium to determine the gaseous and plasma composition of content in a plasma etch chamber. This embodiment uses methods of terahertz spectroscopy to identify the composition of the gas and plasma particles within the plasma etch chamber and applies applied the normally small scale methods of terahertz spectroscopy to a larger environment: the plasma etch chamber, to analyze the chamber for molecules/compounds/atoms. The size of the chamber to be analyzed may vary.

[0076] FIG. 1 shows an example of an apparatus in accordance with an exemplary embodiment of the present invention that may be used in conjunction with a chamber, such as for a plasma etch application. In embodiments, apparatus 30 to be configured to (1) detect the composition of one or more gases or other compositions (e.g., plasmas, liquids) in a chamber 10 during a plasma etch onto a semiconductor wafer 15 (which may be located on a stand 16 during plasma etching ) (e.g., in embodiments, with an accuracy of approximately +/- 1% and a response time of approximately 2 seconds or less. Apparatus 30 may be further configured (2) to also take real time images of the spatial arrangement of particles within the space of the plasma etch chamber

(e.g., in embodiments, with 1-2 seconds in between each image) and / or to (3) detect the temperature of the combined gases in chamber 10 (e.g., in embodiments, within approximately 1 second with an accuracy of approximately +/- 1°C within a range of approximately 100 to 400°C).

The detection of the chemical compositions and the measurement of the gases is significant as it is not always known what gases or the amounts thereof are present in the mixture. In the illustrated example, various gases 20, 21, 22 within the composition may include, for example, CF₄, C₄F6, SF<_>,

NF3, CL₂, HBr, and Ar, to name a few. Moreover, the apparatus may be further configured to (4) detect the gas emission spectrum to detect the level of plasma energy transferred to the gas.

[0077] In the illustrated example, an apparatus 30 for detecting the gas composition, (and possibly also a temperature, and gas emission spectrum) includes an emitter 40 (or more than one emitter such as an array of emitters) for transmitting a high frequency signal of electromagnetic radiation (e.g., in the far infrared or terahertz frequency of the electromagnetic spectrum), into and through a chamber 10, and for performing imaging of the spatial arrangement of particles in the chamber. Emitter 40 may be a laser diode or a high frequency diode, such as a Schottky diode. In embodiments, an emitter 40 may, for example, use high frequency diodes from Virginia Diodes of

Charlottesville, VA U.S.A. In embodiments, the electromagnetic radiation that is emitted is within the terahertz range of electromagnetic radiation, 0.3 to 3 THz. In embodiments, the electromagnetic radiation that is emitted may be limited to a frequency spectrum of frequencies between, and including, 500 GHz to 750 GHz. In other embodiments, the electromagnetic radiation that is to be emitted is in a band of the infrared spectrum or in the millimeter wave spectrum.

[0078| Enclosure 10 has a window 45 through which the electromagnetic radiation passes non-invasively into chamber 10. Window 45 may be a solid piece, such as a piece of quartz glass, that retains gases and other compositions within chamber 10, but serves as an opening to the chamber for the electromagnetic radiation from emitter 40. In embodiments, window 45 is transparent or semi-transparent. Emitter 40 may project a beam or may, as shown in FIG. 7, include an array of heterodyne transmitters. While the array is illustrated as configured for a circular window, the array may have a different shape or pattern. Emitter 40 may be positioned away from window 45 with a beam directed therein, in contact with window 45 or may be incorporated into window 45.

(0079] Apparatus 30 also includes a receiver 50 (or more than one receiver such as an array of receivers) for receiving the electromagnetic radiation (signal) after it has been transmitted through chamber 10 from emitter 40. Receiver 50 may be a receiver for a single beam or may include an array of heterodyne receivers that serve the purpose of capturing images and spatial arrangements of the particles inside of the chamber. Receiver 50 may be positioned outside of chamber 10 outside a second window 55 that, similar to window 45, permits a beam of

electromagnetic radiation to pass therethrough. Receiver 50 may be positioned away from window 55 with a beam directed therein, in contact with window 55 or may be incorporated into window 55. As the embodiment of FIG. 1 includes separate windows 45, 55 for the emitter and for the receiver, it may be termed a two-port or dual-port system.

[0080] Emitter 40 and receiver 50 are operatively connected to one or more controllers, including controller 61 , that are programmed to (i) obtain the signal received by the one or more receivers, (ii) compare the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum, (iii) determine the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the chamber with reference to the database of predetermined spectral signatures, and (iv) generate an image of the chamber and the one or more molecular or atomic components in the chamber based on the determined identities and the spatial arrangement. In embodiments, controller 61 performs these steps. In other embodiments, some or all of the steps may be performed by or in conjunction with one or more other controllers. For example, an amplifier/converter 60 and /or at a network analyzer 62 described below may include controllers mat perform or all some of these steps (if an amplifier/converter 60 and / or network analyzer 62 are implemented in the apparatus).

(0081] Databases of predetermined spectral signals are provided by sources, such as the

National Institute of Standards and Technology (NIST) of Gaithersburg, MD, or other sources, and/or by self-testing for signatures of particles and developing a signature database associated with the apparatus of the present invention.

[0082] The comparison of the received signal to a database to identify molecular or atomic compositions may be performed, in embodiments, by converting the received signal from receiver

50 into a graphical representation (see, e.g., FIG. 3) and comparing the graphical representation to graphical representations of known signals, as described further below. This comparison may be performed, in embodiments, by an amplifier/converter 60 in apparatus 30 that may be included between controller 61 and emitter 40 / receiver 50. Amplifier/converter 60 may include at least an amplifier, a frequency converter, and another controller, separate from controller 61, to obtain the signal received by receiver 50, and generate a graphical representation of the signal.

Amplifier/converter 60 may also compare the graphical representation to the database (not shown) of predetermined spectral signatures that may be accessed, such as via the Internet. Alternatively, a network analyzer 62, also having a controller, may be used instead of amplifier/converter 60 to compare and match the graphical representation of the received signal to graphical representations in the database.

[0083] The amplifier of amplifier/converter 60 is used to amplify the detected/measured signals, while the converter may be used, if necessary, to downconvert the frequency of the signal received by the receivers) to a different frequency for signal processing (e.g., THz to GHz), if network analyzer 62 is used and is not capable of processing very high frequencies in the spectrum detected by receiver 50, such as submillimeter frequencies. Network analyzer 62 may be, for example, a Rohde & Schwarz ZVA40 Vector Network Analyzer driving, for example, a frequency extender module from 500-750 GHz from Virginia Diodes. Similarly, if network analyzer 62 cannot process very high frequencies, amplifier/converter 60 may upconvert (e.g., GHz to THz) the signal from network analyzer 62 to emitter 40.

[0084] In the embodiment of FIG. 1 and in other embodiments described herein, the receivers and emitters may be connected to other elements of the apparatus via wired and/or wireless connections. Where amplifier/controller 60 and/or a network analyzer 62 are provided, controllers in those elements may be in communication with controller 61 via a wired or wireless connection.

[0085] Amplifier/converter 60 and/or controller 61 may also be configured / programmed to control the output of emitter 40 in addition to processing the signal received from receiver 50.

Controller 61 may also serve to regulate the inflow and outflow of compositions (e.g., gas composition) into chamber 10, such as via an inlet 72 and / or an outlet 74, respectively, such as with automated valves, or may communicate information as to compositions and spatial arrangements thereof in chamber 10 to another controller (such as a controller (not shown) that controls chamber 10) that is in communication with controller 61 to regulate the inflow and outflow. While only one inlet 70 and one outlet 72 are shown, there may be additional inlets and/or outlets to more accurately control the compositions that are input and output and the location of these compositions. Apparatus 30 may further include additional hardware, software, and/or circuitry operates in conjunction with emitter 40, receiver 50 and amplifier/converter 60 to detect the composition of the gases in the mixture, the temperature of the gas mixture, and one or more of the additional properties mentioned above.

|0086] In operation, as shown in FIG. 1, with the gas or plasma species (20, 21, 22) shown as an example in the closed environment in chamber 10, emitter 40 emits a beam 41 in a straight line or an array of emitters 40, emit an array of beams 41 that scan the entirety of the enclosure / chamber 10 using the array of beams. Using principles of absorption spectroscopy, the array or the beam emits electromagnetic radiation that interacts with the molecules / atoms of the gas or plasma with which it comes into contact. The radiation may be partially or fully absorbed by the composition in chamber 10. Receiver 50, such as a photoconducting receiver, receives, via window 55, the non-absorbed electromagnetic radiation that passes through the gas or plasma molecules and passes the signal to amplifier/converter 60.

[0087] Amplifier/converter 60 and/or controller 61 then analyzes and interprets the data received from the electromagnetic radiation received by receiver 50 to determine the identity or identities of the molecules or atoms that the emitted electromagnetic radiation interacted with, including the composition of the particles of gas and plasma that are contained within the closed environment and the ratio of the particles of gas and plasma within chamber 10, and a spatial arrangement of the molecules or atoms in chamber 10. This may also include taking measurements of the data and determining ratios of particles / components within the sensed composition in the chamber. Measurements may also be captured of the amount of each molecule or atom found present and the ratios of the components to one another.

[0088| Then, a 2-D or 3-D image/map of the closed environment is created, such as is shown in FIG. 8. The image/map may be used to analyze the processes in real time and to automatically adjust the mixture in chamber 10 via controller 61 that either directly or indirectly controls the flow of particles into inlet 70 and the flow of particles out of outlet 72.

[00891 The method of non-invasively monitoring the closed environment in chamber 10 is accomplished through the utilization of sub-millimeter electromagnetic radiation that scan the closed chamber in the form of a beam or array that does not interfere with the composition of the closed environment or the processes occurring within the closed environment as the plasma etch process occurs. In embodiments, the sub-millimeter waves are within the frequency ranges of either Infrared, Terahertz, or Far Infrared. The beam or array can be in a fixed location or it can be actively moving and scanning the entirety of the closed environment. The beam or array is either reflected off the components within the closed environment or it interacts with receiver SO before it is analyzed. Receiver SO may be a reflecting surface, a photo conducting receiver; or anything that interacts with the beam or array that is not a gas or plasma particle, to name a few. The beam or array received by receiver SO is analyzed to determine the contents of the closed environment.

[0090] FIG. 2 shows a second exemplary embodiment of an apparatus in accordance with the present invention. This apparatus 30' is similar to apparatus 30 shown in FIG. 1 in that it includes an emitter SO' of electromagnetic radiation. However, in this embodiment, emitter SO' is also a receiver of electromagnetic radiation. Emitter SO' emits electromagnetic radiation into the closed environment in order to analyze the radiation after it has come into contact with the contents of the closed environment. After it is reflected off of the reflective surface, the non-absorbed electromagnetic radiation will return to be analyzed by one or more controllers, which may be one of controller 61, a controller at amplifier/converter 60, or a controller at a network analyzer 62.

[0091| In the embodiment of the non-invasive composition sensing and imaging apparatus

30' of FIG. 2, a reflective surface 57 is included within chamber 10 and a single-port emitter / receiver 50' of the electromagnetic radiation provides a source of electromagnetic radiation (e.g., diodes from Virginia Diodes). In embodiments, reflective surface 57 may be a stainless-steel flat surface or another reflective material that will reflect the emitted beam and return it back to the source 50'. The reflective material having reflective surface 57 may be added to the inside of chamber 10 before chamber 10 is closed for use. In embodiments, the window 55 is a made of at least one of quartz, sapphire, or Teflon.

|0092] The beam of electromagnetic radiation that is emitted from the emitter(s) 50' is directed through window 55, and passes through chamber 10 a first time where it may be partially or completely absorbed by the composition before reaching reflective surface 57 inside chamber 10

(or possibly outside a second window (not shown)). Unlike the dual-port embodiment of FIG. 1 where there is a separate receiver, in the embodiment of FIG. 2, reflectometry is employed by providing reflective surface 57 to, like a radar, direct the electromagnetic radiation that has been received (and was unabsorbed in the first pass through chamber 10) back to the source of the electromagnetic radiation 50'. As described, the electromagnetic radiation passes through the gas or plasma particles twice, and emitter/receiver 50' receives the radiation that has not been absorbed by the plasma or gas particles, by absorption spectroscopy. The signal received by the emitter/receiver

50' is transmitted to amplifier/converter 60 / network analyzer 62 where it is then analyzed and interpreted to identify the molecular or atomic components in the composition within chamber 10 and for the spatial arrangement of the components, as described with reference to apparatus of the embodiment shown in FIG. 1. The amplifier/converter 60 / network analyzer 62, interprets the data received from the electromagnetic radiation to determine the identity of the molecules or atoms. The locations/spatial arrangement of the molecules or atoms may men be imaged and, where applicable, the closed environment inside chamber 10 may be regulated via an inflow through inlet 70 and an outflow through outlet 72 so that particles can enter or exit the chamber. These steps may be controlled by one or more controllers, including controller 61 and/or controllers at

amplifier/converter 60 and/or at network analyzer 62.

|0093| FIG. 3 shows a graph of sample data that may be generated by amplifier/converter 60

(or controller 61) using apparatus 30 of FIGS. 1 or 2. The graph shows vacuum normalized data that is compiled for molecules present in the chamber. The graph plots the magnitude of frequencies against the electromagnetic spectra that are received by the receiver SO or 50'. Vacuum normalizing means that the received power of the signal is compared to the vacuum state when no molecule is detected. Thus, the vacuum normalized data describes the relative strength of the signal to the receiver when the signal has interacted with a molecule in comparison to when the signal does not detect anything at all inside the vacuum. The vacuum normalized data is expressed in decibels (db). The vacuum normalization accounts for certain properties of the chamber that can affect the space or create a signal response for the receiver.

[0094] Amplifier/converter 60 analyzes the received signal for the identities of components in the composition by comparison to known signatures of certain components that can be identified by the presence of one or more spikes in the magnitudes at certain frequencies. These known signatures may be obtained from signature tables in existing databases provided by sources, such as the National Institute of Standards and Technology (NIST) of Gaithersburg, MD, or other sources, and/or by self-testing for signatures of particles and developing a signature database associated with the apparatus of the present invention. |0095| As shown in the graph of FIG. 3, for example, a composition of gas and plasma was input into the chamber and the presence of gas and plasma species signatures of the following atoms or molecules was determined by comparison to known signatures from the NIST (National

Institution of Standards and Technology) databases, such as the Atomic Spectra Database (NIST Standard Reference Database 78), which lists associated signatures for each type of molecule or atom that is known:

• Water at 557 GHz and 621 GHz shown at 130 and 160, respectively;

• Carbon at 624 GHz, 630 GHz, and 710 GHz shown at 170, 180, and 150, respectively;

• Hydrogen at 507 GHz, 578 GHz, and 602 GHz shown at 1 10, 140, and 190, respectively;

• Fluorine at 535 GHz as shown at 120, respectively.

Overall, the findings of the experimental model show repeatable and consistent measurements of reactive ion gas etchants accomplished in the submillimeter-wave region. These exemplary findings correspond to a first example in one exemplary plasma etch process. Different etch processes would, for example, lead to detection of a different reflection/absorption spectra. Due to the use of a terahertz emitter, non-invasive composition sensor can perform these tasks in real time or substantially in real time. As used herein, real time information updates on composition and spatial arrangement of the particles in the composition occur within time frames of 1 second to 5 minutes, or, more preferably, within 1-60 seconds, or, more preferably, within 1-2 seconds.

[0096] FIG. 4 shows another exemplary embodiment of a system in accordance with the present invention. This single port embodiment is similar to the embodiment of FIG. 2. However, an off-axis parabolic mirror 231 may be positioned between a source (emitter) / receiver 50' of electromagnetic radiation and a window 55 on chamber 10. As in the embodiment of FIG. 2, reflective surface 57 is included within chamber 10 and a single-port emitter / receiver 50' of the electromagnetic radiation may be used.

[0097| As shown in FIG. 4, electromagnetic radiation is emitted from emitter 50' onto parabolic mirror 231. Mirror 231 may be curved or may be angled diagonally to coUimate the emitted electromagnetic radiation emitted from emitter 50' onto window 55 that serves as an opening for electromagnetic radiation to enter chamber 10. In embodiments, window 55 may be made of quartz. In embodiments, window may include sapphire and /or Teflon.

|0098] The reflection of the electromagnetic radiation from the parabolic mirror 231 enters the window 55 of chamber 10 to interact with the gas and plasma particles. In embodiments, window 55 is a made of at least one of quartz, sapphire, or Teflon. After the electromagnetic radiation passes through window 55 and chamber 10, the unabsorbed portion of the electromagnetic radiation is reflected off of reflective surface 57 (e.g., stainless-steel flat surface or another reflective material and back out of window 55 to parabolic mirror 231 from which it is transmitted to receiver 50'.

[0099] The apparatus of FIG. 4 is configured as a single-port measurement system and a quasi-optical calibration may be performed to allow for error-corrected reflection coefficient measurements. Emitter/receiver 60' may have frequency extender modules and the output of the frequency extender modules in emitter/receiver 50* may be connected to a diagonal feedhorn 241 to illuminate off-axis parabolic mirror 31.

[0100J The use of an off-axis parabolic mirror 231 in terahertz spectroscopy devices is advantageous to coUimate the radiation emitted by the emission source before putting desired molecules in contact with the radiation. This technique serves to focus the emitted electromagnetic radiation so that molecules that come in contact with the focused electromagnetic radiation will be exposed to equally spaced frequencies of electromagnetic radiation. |0101| When feedhora 241 is used, mirror 231 collimates the beam received from feedhorn

41 and directs the collimated beam, via window 55, into chamber 10, which may be, for example, a Semi-Group Reactive Ion Etcher (RIE) Chamber 1 (and may be used in other embodiments). The end of the chamber 10 opposite window 220 may be covered, in its interior, with a stainless steel flat surface 57 that serves a reflector. Therefore, after the electromagnetic radiation is emitted into chamber 10, the electromagnetic radiation passes through the window 55, and comes into contact with the gas and plasma molecules contained, apparatuses 20, 21 , and 22. The electromagnetic radiation is then reflected off of the stainless-steel reflective surface 57 in the chamber, and the electromagnetic radiation returns back to the emitter 50' (via window 55 and parabolic mirror 231).

[0102] Notably, as the electromagnetic radiation returns back to emitter 50', it passes through the gas and plasma molecules twice, which provides more information about the molecules than if the radiation passes through the molecules once. Once the radiation has returned to the emitter source, it is analyzed by amplifier/converter 60. The amplifier/converter 60 analyzes the phase and amplitude of the received electromagnetic radiation to identify the molecules with which the radiation came into contact. Once the analysis by amplifier/converter 60 is completed, graphical information is given that allows a determination as to the identity of the molecules. Within the closed environment is the semiconductor 15 that is being etched. Plasma may be introduced to chamber 10 at inlet 70.

[0103] FIG. 5 shows a graph of the error-corrected reflection spectra over the 500— 750

GHz range for the mirror calibration standard, standard atmosphere (i.e. the chamber vented), the chamber under vacuum and the used standard titanium etch recipe (a SF6/CHF3 mixture). The graph thus shows the relative signal response in comparison to the calibrated baseline signal response that comes from measuring empty space within the vacuum when the signal is reflected off the reflective surface and picked up by the receiver. As expected, reflection from the mirror yields a flat reflection coefficient magnitude of 0 dB. Common resonant features in these data, particularly for vacuum, are anticipated to be associated with the chamber and window geometry. From FIG. 5, common resonant features and different resonances between different gases can be determined. To compare measurements of different gas species in the chamber, the reflection is normalized to that of vacuum (e.g., FIG. 3 which shows the reflection magnitude of the SF6/CHF3 etch mixture normalized to the vacuum response. The measurements illustrated in FIGS. 3 and 5 were obtained where a quartz window was used.

|0104] The apparatus is not limited to one window containing arrays of heterodyne receivers. Rather, multiple windows and multiple arrays of heterodyne receivers can be utilized to create the desired image displaying the spatial arrangement of particles in the chamber in a 2-D or 3-D fashion as demonstrated by apparatus 240 and 242 in FIG. 6. One example of an imaging array design is shown in FIG. 7. Emitter/receiver 2S0 is one of many heterodyne emitters/receivers that can be implemented within either of the windows 240, 242, or be placed outside the windows 240, 242 to obtain images in real time.

[0105] FIG. 6 illustrates another embodiment of the present invention in which non-invasive composition sensing is used for a plasma etch chamber. In this embodiment, multiple windows 240, 242, such as quartz windows, are provided on the outside of chamber 10" and separate emitter/receivers 250 may be positioned at more than one of the windows 240, 242 to direct the electromagnetic radiation into the chamber 10". These emitters/receivers may direct the radiation directly or, in embodiments, parabolic mirrors (not shown) may be used intermediate an emitter / receiver and a window as in FIG. 4. By deploying sensors at multiple windows, the composition components of the chamber may be better sensed in three dimensions and the chamber with components may be imaged/mapped in 3-D. |0106] In embodiments, to best capture an image of the spatial arrangement of the particles inside of the chamber, one or more of the emitter/receivers 250, as shown in FIG. 7, may be implemented as arrays of heterodyne emitters and receivers. Heterodyne emitter and receivers may also be used in the embodiments shown in FIGS. 1, 2, and 4. For example, in FIG. 2, apparatus 40 emits electromagnetic radiation through a window 45, and outside of that window may be an array of heterodyne emitters and receivers as shown in FIG. 7, which may be integrated into the window of the chamber 10 or lie directly outside of the chamber 10.

[0107] As another example, arrays of heterodyne emitters and receivers may be used in the embodiment of FIG. 4 to emit electromagnetic radiation onto and receive a return signal from parabolic mirror 231.

|0108] Through the emission of electromagnetic radiation from the one or more arrays of receivers, the system of the present invention may perform real time imaging of the molecules or atoms, including imaging of identities and the spatial arrangement of the molecules or atoms of the components in the composition. The data obtained, for example, from multiple arrays may be input, such as by controller 61, to software, such as graphic or imaging software for example, that generates a 3-D image showing the chamber and the molecular and/or atomic particles in the chamber that have been detected (in embodiments, with different colors or shading for the different components and for detected temperatures of the components if different from one another), and may indicate their identities and their spatial arrangement as is shown, for example, in FIG. 8. The images may indicate, such as by the size of the illustrated components, the amount of each component in the chamber or in me segment of the open environment that has been sensed. The image(s) may be presented in real-time, which enables a rapid analysis and response (by a user or an automated response), if required. The image/mapping of the spatial arrangement of the particles may show the image graphically or may at least list the latitude and longitude in the 3-D space in a separate sheet In embodiments, this data may be updated as quickly as every 1-2 seconds, to provide real time data.

[0109| In another exemplary embodiment of the present invention, to enable detection throughout a chamber (e.g. of a closed environment) or in a larger segment of an open environment, the one or more emitters or arrays of emitters may be movable about the exterior of the chamber for composition sensing and for 3-D imaging.

[0110| FIG. 9 shows an example of another exemplary embodiment of the present invention where non-invasive composition sensing and imaging takes place in an open environment (i.e., there is no chamber surrounding the environment). The apparatus includes an emitter array 300 and a receiver imaging array 302 placed toward an segment or area within an open environment for which composition sensing is performed. Alternatively, emitter array 300 may also include a receiver array and 302 indicates a reflective surface that is placed on the other side of the segment / area for which composition sensing is performed, substantially opposite the

emitter/receiver/imaging array 300.

[0111] In this embodiment, emitter/imaging array/receiver device 300 emits electromagnetic radiation, that interacts with particles in a segment located between array 300 and receiver/reflective surface 302. (Receiver/reflective surface 302 may be a receiver that is operatively connected to amplifier/converter 60 or may be a reflective surface that reflect the electromagnetic radiation back to emitter/receiver 300, in which case receiver/reflective surface 302 need not be operatively connected to amplifier/converter 60.) After interacting with particles, the electromagnetic radiation interacts with the receiver/reflective surface 302 to sense the molecules of components in the open space that is tested and the spatial arrangement at least for the section covered by array 300 is transmitted to a controller that is an amplifier/converter 60 or includes an amplifier/converter 60 that may amplify and frequency convert the received signal to determine the components of the composition and perform 2-D or 3-D imaging of the segment of the open environment, the identities and spatial arrangement of the detected components. The data will provide the composition of the particles in the tested (sensed) segment or area of the open environment as well as the spatial arrangement of the particles demonstrated by FIG. 9. Additionally, data may be fed from amplifier/converter 60 to a controller 61 associated with the apparatus to control, to the extent possible, the composition (e.g., gases) in the space being measured, such as by automatically controlling an emission, and/or filtering of gases in the area surrounding the space of interest between array 300 and receiver/reflective surface 302, or automatically activated a large fan adjacent the space to remove harmful gases that are detected in a particular area. An image of the segment of the open environment that is captured by the apparatus in FIG. 9 may be generated, similar to the image shown in FIG. 8.

(0112] Thus, an apparatus in accordance with an embodiment of the present invention may include one or more sensors that capture an image displaying the spatial arrangement of gas and plasma particles, detect the composition of gases and plasmas in a mixture, such as the gas species in the mixture, the temperature of the mixture, and one or more other additional properties of the gases and plasmas in the chamber such that one or more of the composition of the gases and plasmas, and one or more of these other properties may be adjusted, such as with a controller that receives the detected values. In embodiments, one or more of the sensors include an emitter and a receiver that operate in real-time. The apparatus may further include additional hardware, software, and/or circuitry that operate in conjunction with the one or more sensors to detect the compositions of materials, temperature and one or more other properties of the gases during semiconductor or composition processing. The apparatus may include hardware and software that allow for noninvasive, real time imaging of the space in which the matter and/or materials desired to be detected are contained within. The one or more sensors should be non-destructible by the composition that they are being used to measure and should be non-destructive to and not alter the material / matter that they are measuring.

[0113] The one or more additional properties mat may be detected, measured and /or controlled include one or more of the following:

• Plasma Density

• Anisotropy

• Plasma Energy

• Pressure

• Etching Rate

• Molecular Density of the Gas Particles

• Particle Detection

• Gas Emission Spectrum

• Spatial Imaging of Particles

• High Resolution Imaging of Environment

and, in embodiments, the apparatus may further be configured to detect one or more of the following:

• Gas Species

• Molecular Density

• Particles

• Solid, liquid, gas, and / or plasma composition.

|0114] A method in accordance with an exemplary embodiment of the present invention includes detecting the composition of gases in a mixture, including the gas species in the mixture, the temperature of the mixture, and the one or more other additional properties of the gases in the chamber, as described above, while also capturing an image displaying the spatial arrangement of gas and plasma particles in the space.

[0115| In another exemplary embodiment of the invention, an apparatus and method is provided for determining the composition of at least one of gases, solids, liquids or plasmas in an accurate, reliable, and repeatable way in one or more applications that require non-invasive and real-time capability with a flexible and re-configurable scheme, while capturing an image of the space in which the gases, liquids, solids, or plasmas showing their spatial arrangement in a given space, captured in real time.

|0116] An apparatus and method of the present invention thus enables the accurate, reliable and repeatable detection and control of reactions and mixtures in a non-invasive manner so that the semiconductor processes or composition processes that are being performed are undisturbed by the measurement of the gas mixture. Moreover, in embodiments, the measurements may be obtained in real-time. As a result, the measurements are more accurate and reliable. Furthermore, imaging of the spatial arrangement of particles composing the gas mixture in a chamber or in an open environment provides information that can lead to better control of the environment of the chamber, resulting in more uniform etching. These improved measurements may, in turn, be used to better control the composition and, consequently, may result in a desired higher yield of processed products.

[0117] Now that embodiments of the present invention have been shown and described in detail, various modifications and improvements thereon will become readily apparent to those skilled in the art Accordingly, the exemplary embodiments of the present invention, as set forth above, are intended to be illustrative, not limiting. The spirit and scope of the present invention is to be construed broadly and not limited by the foregoing specification.

Claims

CLAIMS What is claimed is:

1. An apparatus for non-invasive detection and imaging of molecular or atomic components in a composition, comprising at least one of a gas, a liquid, a plasma, or a solid, in a chamber comprising:

(a) one or more emitters that are configured to emit electromagnetic radiation comprising a spectmm of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and are positioned to direct the emitted electromagnetic radiation from outside the chamber into the chamber through a first window on the chamber, wherein the first window comprises at least one transparent or semitransparent section on the chamber, such that the electromagnetic radiation that is emitted by the one or more emitters is transmitted into the chamber through the first window and passes through the chamber;

(b) one or more receivers that are positioned and configured to receive a signal comprising the electromagnetic radiation that remains after any absorption by the composition in the chamber of the emitted electromagnetic radiation, and to detect, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters; and

(c) one or more controllers, operatively connected to the one or more emitters and the one or more receivers, wherein the one or more controllers are programmed to (i) obtain the signal received by the one or more receivers, (ii) compare the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum, (iii) determine the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the chamber with reference to the database of predetermined spectral signatures, and (iv) generate an image of the chamber and the one or more molecular or atomic components in the chamber based on the determined identities and the spatial arrangement.

2. The apparatus of claim 1, wherein the one or more emitters and the one or more receivers are positioned outside of the first window, wherein the chamber has an interior reflective surface opposite the one or more receivers to reflect the electromagnetic radiation that passes through the chamber, and wherein the one or more receivers receive the electromagnetic radiation that is reflected from the interior reflective surface back to the one or more receivers.

3. The apparatus of claim 1 , further comprising a parabolic mirror positioned between the one or more emitters and the first window to capture the electromagnetic radiation emitted by the one or more emitters and direct the electromagnetic radiation through the first window.

4. The apparatus of claim 1 , wherein the one or more receivers are positioned outside of a second window' in the chamber and substantially opposite the one or more emitters, wherein the second window comprises at least a second transparent or semitransparent section of the chamber to receive the electromagnetic radiation after it has passed through the chamber.

5. The apparatus of claim 1, wherein the one or more controllers are further programmed to generate the image of the one or more molecular or atomic components in 3-D based on the spatial arrangement of the composition in the chamber.

6. The apparatus of claim 1, wherein the one or more controllers are further

programmed to transmit a second signal to regulate an inflow and an outflow of one or more particles in the chamber based on the determination of the identities and the spatial arrangement of the one or more molecular or atomic components in the composition within the chamber.

7. The apparatus of claim 6, wherein the chamber is for plasma etching of

semiconductors, and the regulation of the inflow and the outflow allows for an automated adjustment of at least one of an amount, mixture, or location of the molecular or atomic components in the chamber during the plasma etching.

8. The apparatus of claim 1, wherein the one or more controllers are further

programmed to track the identities and the spatial arrangement of the composition in the chamber over time.

9. The apparatus of claim 1, wherein the one or more emitters comprise a heterodyne array of emitters and the one or more receivers comprise a heterodyne array of receivers.

10. The apparatus of claim 1, wherein the one or more controllers are further programmed to measure an amount of the molecular or atomic components identified in the composition.

1 1. An apparatus for non-invasive detection and imaging of molecular or atomic components in a composition, comprising at least one of a gas, a liquid, a plasma, or a solid, in an open environment, comprising:

(a) one or more emitters that are configured to electromagnetic radiation comprising a spectrum of fiequencies in at least one of a terahertz, infrared or millimeter wave spectrum and are positioned to direct the emitted electromagnetic radiation through a segment of the open

environment;

(b) one or more receivers that are positioned and configured to receive a signal comprising the electromagnetic radiation that remains after any absorption by the composition in the segment of the open environment of the emitted electromagnetic radiation, and to detect, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters; and

(c) one or more controllers, operatively connected to the one or more emitters and the one or more receivers, wherein the one or more controllers are programmed to (i) obtain the signal received by the one or more receivers, (ii) compare the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum, (iii) determine the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the open environment with reference to the database of predetermined spectral signatures, and (iv) generate an image of the segment of the open environment and the one or more molecular or atomic components in the segment of the open environment based on the determined identities and the spatial arrangement.

12. The apparatus of claim 11 , wherein the controller is further programmed to generate the image of the one or more molecular or atomic components in 3-D.

13. The apparatus of claim 11 , wherein the controller is further programmed to track the identities and the spatial arrangement of the composition in the segment of the open environment over time.

14. The apparatus of claim 1 1, wherein the one or more emitters comprise a heterodyne array of emitters and the one or more receivers comprise a heterodyne array of receivers.

15. A method for non-invasive detection and imaging of molecular or atomic components in a composition, comprising at least one of a gas, a liquid, a plasma, or a solid, in a chamber, the method comprising:

(a) emitting, by one or more emitters, electromagnetic radiation comprising a spectrum of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and directing the emitted electromagnetic radiation from outside the chamber into the chamber through a first window on the chamber, wherein the first window comprises at least one transparent or semitransparent section on the chamber, such that the electromagnetic radiation that is emitted by the one or more emitters is transmitted into the chamber through the first window and passes through the chamber;

(b) receiving, by one or more receivers, a signal comprising the electromagnetic radiation that remains after any absorption by the composition in the chamber of the emitted electromagnetic radiation, and detecting, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters;

(c) obtaining, by one or more controllers operatively connected to the one or more emitters and the one or more receivers, the signal received by the one or more receivers;

(d) comparing, by the one or more controllers, the signal to a database of predetermined spectral signatures that is accessible to the one or more controllers, wherein the spectral signatures identify molecular or atomic compositions based on the amplitudes at one or more frequencies within the received spectrum;

(e) determining, by the one or more controllers, the identities and spatial arrangement of the one or more molecular or atomic components in the composition within the chamber with reference to the database of predetermined spectral signatures; and

(f) generating, by the one or more controllers, an image of the chamber and the one or more moleculai" or atomic components based on the determined identities and the spatial arrangement.

16. The method of claim 15, wherein the chamber has an interior reflective surface opposite the one or more receivers to reflect the electromagnetic radiation that passes through the chamber, and wherein the step of receiving, by the one or more receivers, of the signal comprises receiving electromagnetic radiation that is reflected from the interior reflective surface back to the one or more receivers.

17. The method of claim 15, wherein a parabolic mirror is positioned between the one or more emitters and the first window, and wherein the step of directing the emitted electromagnetic radiation from outside the chamber into the chamber comprises directing the electromagnetic radiation toward the parabolic mirror such that it is reflected from the parabolic mirror through the first window into the chamber.

18. The method of claim 15, wherein the one or more receivers are configured to be positioned outside of a second window' in the chamber and substantially opposite the one or more emitters, and wherein the step of receiving, by the one or more receivers, of the signal comprises receiving electromagnetic radiation that passes out of the second window of the chamber after it has passed through the chamber.

19. The method of claim 15, wherein the step of generating, by the one or more controllers, the image of the one or more molecular or atomic components comprises generating the image in 3-D.

20. The method of claim 15, further comprising transmitting, by the one or more controllers, a second signal to regulate an inflow and an outflow of one or more particles in the chamber based on the determination of the identities and the spatial arrangement of the one or more molecular or atomic components in the composition within the chamber.

2 1. The method of claim 15, further comprising tracking, by the one or more controllers, the identities and the spatial arrangement of the composition in the chamber over time.

22. The method of claim 15, further comprising measuring an amount of the molecular or atomic components identified in the composition.

23. The method of claim 15, wherein steps (b) to (f) are performed in real-time.

24. A method for non-invasive detection and imaging of molecular or atomic

components in a composition, comprising at least one of a gas, a liquid, a plasma, or a solid, in an open environment, the method comprising:

(a) emitting, by one or more emitters, electromagnetic radiation comprising a spectrum of frequencies in at least one of a terahertz, infrared or millimeter wave spectrum and directing the emitted electromagnetic radiation into a segment of the open environment;

(b) receiving, by one or more receivers, a signal comprising the electromagnetic radiation that remains after any absorption by the composition, in the segment of the open environment, of the emitted electromagnetic radiation, and detecting, in the received electromagnetic radiation, amplitudes of frequencies within the spectrum of frequencies that were emitted by the one or more emitters;

(f) generating, by the one or more controllers, an image of the segment of the open environment and the one or more molecular or atomic components in the segment of the open environment based on the determined identities and the spatial arrangement.

The method of claim 24, wherein steps (b) to (f) are performed in real-time.