Apparatus and method for using a quartz crystal microbalance and flow cell - Patent Application 20070122997

Abstract

An apparatus comprising: a quartz crystal microbalance having a quartz crystal resonator with a coating; and a flow cell positioned to flow a liquid over the coating.

Description

[Technical Field]

[0001] The present invention relates to an apparatus and method, and particularly, but not exclusively, to an apparatus and method for monitoring the etching of materials using a quartz crystal microbalance. [Background technology]

[0002] In semiconductor device fabrication, several different processes are typically performed on semiconductor wafers to fabricate semiconductor devices on the semiconductor wafers. These processes typically involve etching a layer of material previously deposited on the surface of the semiconductor wafer to remove portions of the material. This is typically accomplished by dispensing etching chemicals onto the surface of the semiconductor wafer to etch the layer of material on the surface of the semiconductor wafer.

[0003] To etch a predetermined amount of material, a predetermined etching chemistry (e.g., having a predetermined concentration and / or a predetermined pH value) can be dispensed onto the surface of a semiconductor wafer for a predetermined time. However, the etch rate of a material can be greatly affected by the properties of the etching chemistry, and small changes in the properties of the etching chemistry (e.g., concentration and / or pH value) can cause large variations in the amount of etching that occurs within a given time.

[0004] A single etching cycle performed on a material layer on the surface of a semiconductor wafer to etch the material can remove as little as 10 nm (100 Å) of the thickness of the material layer, therefore, high sensitivity is required to monitor the etching, even when multiple etching cycles are performed.

[0005] It is known to use external metrology tools to detect the amount of etching of a material layer on the surface of a semiconductor wafer, for example, by using a high-precision microbalance to measure the change in mass of the semiconductor wafer caused by etching, or by using ellipsometry to detect the reduction in material thickness caused by etching. However, such techniques require the semiconductor wafer to be transported to the external metrology tool, which can take a significant amount of time and can delay semiconductor device fabrication. In addition, such techniques cannot monitor the amount of etching in situ, but instead require the provision of an additional external metrology tool.

[0006] It is also known to indirectly estimate the amount of etching of a material layer on the surface of a semiconductor wafer by measuring the concentration and / or pH value of an etching chemical that has been (or will be) dispensed onto the surface of the semiconductor wafer. However, these techniques do not directly measure the amount of etching of a material layer by an etching chemical. In addition, these techniques may require complex or expensive devices to perform the measurements, especially when dealing with etching chemicals consisting of several different components, or when bath loading / aging may play a role. Bath loading / aging refers to the accumulation of etched material from the material layer as contaminants in the etching chemical when the etching chemical is recovered and reused after being used to etch the material layer. The presence of such contaminants in the etching chemical can reduce the etching rate of the etching chemical, for example, by reducing the concentration and / or pH value of the etching chemical.

[0007] Therefore, there is a need for improved techniques for monitoring the etching of material layers, for example, techniques that can be used in situ and / or without the need for additional external metrology tools.

[0008] A quartz crystal microbalance is a device that can be used to measure changes in mass per unit area at the surface of a quartz crystal resonator by measuring the change in the resonant frequency of the quartz crystal resonator caused by changes in mass per unit area at the surface of the quartz crystal resonator.

[0009] A quartz crystal microbalance can measure, for example, 1 ng / cm 2 It is possible to measure the change in mass per unit area at the surface of a quartz crystal resonator with a sensitivity as high as 0.01 nm (0.1 Å). Depending on the density of the material, this sensitivity may enable detection of changes in material thickness on the order of 0.1 Å (0.01 nm).

[0010] Quartz crystal microbalances operate based on the piezoelectric effect, where application of an electric field across a quartz crystal causes mechanical deformation of the crystal. By applying an oscillating electric field of the appropriate frequency to the crystal, the crystal can be made to oscillate at a specific resonant frequency. This resonant frequency can be the fundamental resonant frequency or a higher-order resonant frequency.

[0011] The specific resonant frequency of a quartz crystal depends on the mass per unit area at the crystal's surface. Therefore, a change in mass per unit area at the crystal's surface will cause a shift in the crystal's resonant frequency. Therefore, by measuring the shift in the crystal's resonant frequency, the change in mass per unit area at the crystal's surface can be calculated. For example, the change in mass per unit area at the crystal's surface can be calculated from the shift in the crystal's resonant frequency using the following formula:

number

[0012] Δm is the change in mass per unit area (e.g., g / cm) at the surface of the crystal. 2 where Δf is the shift in the fundamental resonant frequency of the crystal in Hz, and C is a constant that depends on the properties of the crystal used (e.g., g / (cm 2This formula corresponds to the Sauerbrey formula, which is well known in the art, and will not be described in detail here.

[0013] FIG. 1 is a simplified schematic diagram of a quartz crystal resonator 1 used in a quartz crystal microbalance. As shown in FIG. 1, the quartz crystal resonator 1 includes a quartz crystal wafer 3. The quartz crystal wafer 3 may be cut from a bulk quartz crystal at a specific orientation appropriate to the crystal axes of the bulk quartz crystal. For example, the quartz crystal wafer 3 may be an AT-cut quartz crystal wafer. Additionally, the quartz crystal resonator 1 includes a first electrode 5 provided on a first major surface (e.g., top surface) of the quartz crystal wafer 3 and a second electrode 7 provided on a second major surface (e.g., bottom surface) opposite the quartz crystal wafer 3. Thus, the quartz crystal wafer 3 is sandwiched between the first and second electrodes 5 and 7.

[0014] The electrodes may, for example, include or be made of gold.

[0015] Typically, the first and / or second electrodes 5 and 7 are provided on only a portion of the first and / or second main surfaces of the quartz crystal wafer 3, thereby exposing a portion of the first and / or second main surfaces of the quartz crystal wafer 3.

[0016] In FIG. 1 , an AC current and / or voltage source 9 is electrically connected to the quartz crystal resonator 1. Specifically, the AC current and / or voltage source 9 is connected to the first and second electrodes 5 and 7 of the quartz crystal resonator 1 and is configured to apply an AC current and / or voltage to the first and second electrodes 5 and 7. By applying an AC current and / or voltage of an appropriate frequency to the first and second electrodes 5 and 7, the quartz crystal wafer 3 can be caused to oscillate at a resonant frequency of the quartz crystal wafer 3, e.g., a fundamental resonant frequency. This resonant frequency of the quartz crystal wafer 3 can be detected in a conventional manner, thereby detecting a change in resonant frequency caused by a change in mass per unit area at the surface of the quartz crystal wafer 3. This is the general principle by which a quartz crystal microbalance operates.

[0017] Figure 2 is a simplified schematic diagram of a quartz crystal microbalance 2. The quartz crystal microbalance 2 comprises the quartz crystal resonator 1 of Figure 1. Specifically, the quartz crystal resonator 1 comprises the quartz crystal wafer 3 sandwiched between first and second electrodes 5 and 7, as shown in Figure 1 and described above. In practice, the quartz crystal microbalance 2 typically comprises a holder in which the quartz crystal resonator 1 is held with at least one major surface (e.g., the top surface) of the quartz crystal resonator 1 exposed.

[0018] 2 , the quartz crystal microbalance 2 further includes a controller 4 and crystal oscillator electronics 6. The crystal oscillator electronics 6 is electrically connected to the crystal resonator 1 and configured to drive oscillation of the crystal resonator 1, for example, by applying an alternating current and / or voltage to first and second electrodes 5 and 7 of the crystal resonator 1. The controller 4 is electrically connected to the crystal oscillator electronics 6 and configured to control the operation of the crystal oscillator electronics 6 to drive oscillation of the crystal resonator 1 and to detect the resonant frequency of the crystal resonator 1, for example, the fundamental resonant frequency of the crystal resonator 1.

[0019] Of course, the quartz crystal microbalance 2 may include additional components beyond those shown in FIG.

[0020] FIG. 3 is a simplified schematic diagram of an oscillator circuit for detecting the resonant frequency of a crystal resonator 1 that may be used in a crystal microbalance 2. As shown in FIG. 3, the crystal resonator 1 is placed in an oscillator circuit in which the crystal resonator 1 is driven into oscillation by an automatic gain control amplifier 8. The crystal resonator 1 is terminated to a grounded load resistor 10. By feeding the voltage on the load resistor 10 back to the input of the automatic gain control amplifier 8, with sufficient gain, the oscillator circuit will oscillate at a frequency that results in a phase shift around the loop of 0° or an integer multiple of 360°. This phase condition can be met when the crystal resonator 1 is at resonance. Therefore, by determining the oscillation frequency of the oscillator circuit of FIG. 3, the resonant frequency of the crystal resonator 1 can be detected.

[0021] Of course, it is possible to detect the resonant frequency of the crystal resonator using a different type of circuit or detector than the oscillator circuit shown in FIG.

[0022] A variety of different types of quartz crystal microbalances are commercially available and their operation is well understood and described in the literature, therefore their operation will not be described further here.

[0023] Quartz crystal microbalances have been used in the past to monitor the deposition or adsorption of materials on the surface of quartz crystal resonators, for example, to monitor vapor-phase film deposition, or molecular adsorption at a crystal interface in a liquid, or self-assembled monolayer (SAM) coating on a crystal interface in a liquid.

[0024] The present invention has been devised in light of the above considerations. Summary of the Invention

[0025] The present invention may solve one or more of the problems identified above.

[0026] Most generally, the present invention relates to the use of a quartz crystal microbalance to monitor or investigate the etching of a coating formed on the quartz crystal resonator of the quartz crystal microbalance.

[0027] As mentioned above, a quartz crystal microbalance can be used to measure, for example, 1 ng / cm 2 It is possible to measure the change in mass per unit area at the surface of the quartz crystal resonator with a sensitivity as high as 0.01 nm (0.1 Å). Depending on the density of the coating material, this sensitivity may enable detection of changes in coating thickness on the order of 0.1 Å (0.01 nm).

[0028] A single etching cycle performed on a material layer to etch the material may remove as little as 100 Å (10 nm) of the material layer thickness, or as little as 10 Å (1 nm) of the material layer thickness. Thus, a quartz crystal microbalance can provide sufficiently high sensitivity for monitoring etching. Additionally, a quartz crystal microbalance may be used to provide in-situ or in-line monitoring of etching.

[0029] According to a first aspect of the present invention, there is provided an apparatus comprising a quartz crystal microbalance comprising a quartz crystal resonator having a coating, and a flow cell arranged to flow a liquid over the coating.

[0030] The first aspect of the present invention may have any one of the following optional features, or any combination where compatible.

[0031] The quartz crystal microbalance may have, for example, any of the features of the quartz crystal microbalance described above and / or shown in FIGS.

[0032] A quartz crystal microbalance comprises a quartz crystal resonator.

[0033] The quartz resonator may comprise a quartz crystal or a quartz crystal wafer.

[0034] The crystal resonator may be a crystal oscillator.

[0035] The quartz crystal resonator (and / or quartz crystal or quartz crystal wafer) may be disk-shaped or wafer-shaped.

[0036] The quartz resonator (and / or quartz crystal or quartz wafer) may have, for example, a diameter of 25 mm, or a diameter of 20 mm to 30 mm.

[0037] The quartz crystal resonator (and / or quartz crystal or quartz crystal wafer) may have symmetrical first and second major surfaces or faces.

[0038] The quartz crystal resonator may comprise a quartz crystal or quartz crystal wafer cut from a bulk quartz crystal at a specific orientation relative to the crystallographic axes of the bulk quartz crystal. For example, the quartz crystal or quartz crystal wafer may be an AT-cut quartz crystal or quartz crystal wafer.

[0039] The quartz crystal or quartz crystal wafer may be sandwiched between a pair of electrodes.

[0040] A quartz crystal resonator may comprise a pair of electrodes sandwiching a quartz crystal or quartz crystal wafer.

[0041] The quartz crystal resonator may include a first electrode disposed on a first major surface or surface of the quartz crystal or quartz crystal wafer, and a second electrode disposed on an opposite second major surface or surface of the quartz crystal or quartz crystal wafer.

[0042] The quartz crystal microbalance may comprise an alternating current and / or voltage source electrically connected to the electrodes and configured to apply an alternating current and / or voltage to the electrodes.

[0043] The electrodes may, for example, include or be made of gold.

[0044] The first electrode may be provided on only a portion of the first main surface or major surface of the quartz crystal or quartz crystal wafer, thereby exposing a portion of the first main surface or major surface of the quartz crystal or quartz crystal wafer.

[0045] The second electrode may be provided on only a portion of the second main surface or major surface of the quartz crystal or quartz crystal wafer, thereby exposing a portion of the second main surface or major surface of the quartz crystal or quartz crystal wafer.

[0046] The quartz crystal microbalance may include crystal oscillator electronics for driving oscillation of the quartz crystal resonator. For example, the crystal oscillator electronics may be configured to apply an alternating current and / or voltage to the quartz crystal resonator, e.g., to first and second electrodes of the quartz crystal resonator.

[0047] The quartz crystal microbalance may include a controller for controlling operation of the quartz crystal microbalance, for example, the controller may be configured to control the crystal oscillator electronics to drive oscillation of the quartz crystal resonator and to detect the resonant frequency of the quartz crystal resonator.

[0048] The quartz crystal microbalance may include an oscillator circuit for detecting the resonant frequency of the quartz crystal resonator.

[0049] The crystal resonator may have a fundamental resonant frequency on the order of 5 MHz.

[0050] Coating may refer to a layer of material provided on a surface of a quartz crystal resonator, for example, on the surface of a quartz crystal or quartz crystal wafer of a quartz crystal resonator.

[0051] The coating may be a film.

[0052] The coating may be provided on a major surface or faces of the quartz crystal resonator (or quartz crystal or quartz crystal wafer).

[0053] The coating may be provided on a major surface or only a major surface of the quartz crystal resonator (or quartz crystal or quartz crystal wafer).

[0054] The coating may be provided on only a portion of the surface of the quartz resonator (or quartz crystal or quartz wafer).

[0055] The coating may be provided on only a portion of the quartz resonator (or crystal or quartz wafer).

[0056] The coating may be a layer of material deposited on the surface of the quartz crystal resonator (or quartz crystal or quartz crystal wafer).

[0057] The quartz crystal or quartz crystal wafer may have a major surface (eg, a top surface), a portion of which is covered by the first or second electrode and a portion of which is covered by the coating.

[0058] The first electrode may be formed on the top surface (main surface) of the quartz crystal wafer so as to cover only a portion of the top surface of the quartz crystal wafer, and the coating may be formed on another portion of the top surface of the quartz crystal wafer so as to cover another portion of the top surface of the quartz crystal wafer. In other words, the first electrode and the coating may be provided on different portions of the top surface of the quartz crystal wafer.

[0059] The coating may be made of only a single material, or the coating may include several different materials.

[0060] The coating may be deposited on the quartz resonator by, for example, PVD, although other types of deposition or coating techniques are known and may alternatively be used, for example, CVD or ALD.

[0061] The mass per unit area of ​​the coating affects the resonant frequency of oscillation of the quartz crystal resonator. In other words, the resonant frequency of the quartz crystal resonator depends on the mass per unit area of ​​the coating, so that a change in the mass per unit area of ​​the coating causes a shift in the resonant frequency of the quartz crystal resonator. Therefore, a quartz crystal microbalance can be used to monitor the mass per unit area of ​​the coating on the quartz crystal resonator.

[0062] A decrease in the mass per unit area of ​​a crystal resonator may increase the resonant frequency of the crystal resonator.

[0063] The flow cell may be configured and / or adapted to flow a liquid over the coating.

[0064] A flow cell can refer to any flow channel, or flow chamber, or passage, or tube arranged to direct the flow of a liquid over a coating.

[0065] The flow cell is positioned to bring the liquid into contact with the coating.

[0066] The flow cell may include a channel or flow chamber that allows a liquid to contact the coating and flow over the coating.

[0067] Flowing a liquid over a coating can mean moving or passing a liquid over the coating.

[0068] The flow cell may be configured to bring the liquid into contact with some, most, or all of the coating.

[0069] The flow cell may comprise an inlet for connecting the flow cell to a source of liquid, whereby liquid can enter the flow cell via the inlet.

[0070] The flow cell may comprise an outlet for connecting the flow cell to a fluid path so that liquid can exit the flow cell via the outlet.

[0071] The flow cell may be connected to a recirculation loop, whereby liquid is recirculated between a source of liquid and the flow cell.

[0072] The flow cell may include a channel or flow chamber that connects an inlet to an outlet, or that connects to an inlet and an outlet, and that allows a liquid to contact the coating and flow over the coating.

[0073] The volume of the channel or flow chamber (e.g., from the inlet of the channel or flow chamber to the outlet of the channel or flow chamber) may be 10 mL or less. The volume may be 0.1 mL or more. The volume may be 0.1 mL or more and 10 mL or less. In certain embodiments, the volume may be 1 mL or more and 2 mL or less, e.g., 1.0 mL or more and 2.0 mL or less, e.g., about 1 mL.

[0074] The volume of the region of the channel or flow chamber opposite (e.g., directly opposite) the area of ​​the quartz resonator in contact with the liquid may be 2 mL or less, e.g., 2.0 mL or less. The volume may be 0.05 mL or more. The volume may be 0.05 mL or more and 2 mL or less, e.g., about 0.15 mL.

[0075] The volume of the region of the channel or flow chamber, defined by the area of ​​the quartz resonator in contact with the liquid multiplied by the distance between the quartz resonator and the opposite surface of the channel or flow chamber, may be 2 mL or less, e.g., 2.0 mL or less. The volume may be 0.05 mL or more. The volume may be 0.05 mL or more to 2 mL or 2.0 mL or less, e.g., about 0.15 mL.

[0076] The distance between the area of ​​the quartz crystal resonator in contact with the liquid and the opposite surface of the channel or flow chamber may be between 0.2 mm and 5 mm, for example about 2 mm.

[0077] The area of ​​the quartz crystal resonator in contact with the liquid is 0.1 cm 2 More than 10cm 2 Below, for example, about 0.5 cm 2 may be.

[0078] The flow cell may include or be made of a chemically inert material.

[0079] The flow cell may include or be made of polytetrafluoroethylene (PTFE).

[0080] The quartz crystal resonator is positioned within or relative to the flow cell so that the coating on the quartz crystal resonator (or quartz crystal or quartz crystal wafer) comes into contact with the liquid flowing through the flow cell.

[0081] The quartz crystal resonator may be received in, received by, or at least partially received in, or received by, the flow cell.

[0082] The flow cell may have an opening or window through which the quartz resonator is (at least partially) positioned or received, such that a coating on the quartz resonator comes into contact with the liquid flowing through the flow cell.

[0083] The flow cell may contain a quartz resonator such that a coating on the quartz resonator is in contact with a liquid flowing through the flow cell. For example, the flow cell may comprise a space or cavity in which the quartz resonator is contained.

[0084] Preferably, the quartz resonator is removable from the flow cell, for example the flow cell may be openable to remove the quartz resonator from a space or cavity within the flow cell, or the quartz resonator may be removable through a window or opening in the flow cell.

[0085] The flow cell may be configured to provide or allow symmetrical liquid flow within the flow cell over the coating, which may prevent or reduce uneven etching of the coating.

[0086] The device may include a temperature control mechanism for controlling the temperature of the flow cell. For example, the temperature control mechanism may be configured to maintain the temperature of the flow cell constant within ±0.5°C, or ±0.1°C.

[0087] The apparatus may include a heater and / or cooler for controlling the temperature of the flow cell, for example, the heater and / or cooler may be configured to maintain the temperature of the flow cell constant to within ±0.5°C, or ±0.1°C.

[0088] The apparatus may include a temperature control mechanism for controlling the temperature of the liquid in the flow cell. For example, the temperature control mechanism may be configured to maintain the temperature of the liquid in the flow cell constant within ±0.5°C, or within ±0.1°C.

[0089] The apparatus may include a heater and / or cooler for controlling the temperature of the liquid in the flow cell, for example, the heater and / or cooler may be configured to maintain the temperature of the liquid in the flow cell constant to within ±0.5°C, or ±0.1°C.

[0090] The apparatus may include a temperature control mechanism for controlling the temperature of the crystal resonator. For example, the temperature control mechanism may be configured to maintain the temperature of the crystal resonator constant within ±0.5°C, or ±0.1°C.

[0091] The apparatus may include a heater and / or cooler for controlling the temperature of the crystal resonator, for example, the heater and / or cooler may be configured to maintain the temperature of the crystal resonator constant within ±0.5°C, or ±0.1°C.

[0092] Of course, a single temperature control mechanism, or a single heater and / or cooler, may be configured to provide one or more of the temperature control functions described above.

[0093] The coating is SiO2, or Al2O3, or TiN, or Cu, or W, or Si, or Si3N4, or TaN, or Co, or SiO x , or W-doped C, or Co, or SnO x , or C (e.g., polymer, or amorphous, or diamond-like, etc.), or SiC x N v Such materials are typically etched during the fabrication of semiconductor devices.

[0094] The coating may have a thickness of 0.5 μm or more. Assuming that a typical etching cycle removes about 10 nm (100 Å) of the coating, this means that a 0.5 μm thick coating can be used to monitor about 50 etching cycles. If less material is removed per etching cycle, e.g., 1 nm (10 Å) of the coating, the coating may be used to monitor more etching cycles, e.g., 500 etching cycles. This may increase the lifetime of the quartz crystal resonator.

[0095] The coating may have a thickness of 0.01 μm or more, and / or 0.1 μm or more, and / or 0.5 μm or more, and / or 1 μm or more, and / or 5 μm or less, and / or 10 μm or less.

[0096] The coating may have a thickness of 0.01 μm or more, 5 μm or less, or 10 μm or less.

[0097] For example, thicknesses as small as 0.01 μm may be used to detect whether etching has occurred.

[0098] The coating may have a thickness of 0.1 μm or more, 5 μm or less, or 10 μm or less.

[0099] The coating may have a thickness of 1 μm or more, 5 μm or less, or 10 μm or less.

[0100] The device may be configured to detect the resonant frequency of the crystal resonator, for example the fundamental resonant frequency, which is the resonant frequency of oscillation of the crystal resonator.

[0101] The quartz crystal microbalance may be configured to detect the resonant frequency, for example the fundamental resonant frequency, of the quartz crystal resonator.

[0102] The device or quartz crystal microbalance may comprise a detector configured to detect the resonant frequency, for example the fundamental resonant frequency, of the quartz crystal resonator.

[0103] The quartz crystal microbalance may include an oscillator circuit for detecting the resonant frequency of the quartz crystal resonator, for example, the oscillator circuit may be as shown in Figure 3 and described above.

[0104] The device or quartz crystal microbalance may be configured to determine a shift in the resonant frequency of the quartz crystal resonator, e.g., a fundamental resonant frequency. For example, the device or quartz crystal microbalance may include a controller or processor configured to determine the shift in the resonant frequency of the quartz crystal resonator. For example, the controller or processor may be configured to determine or calculate the shift in the resonant frequency of the quartz crystal resonator based on the resonant frequency of the quartz crystal resonator detected or determined at two different times (e.g., before and after an etchant or chemical is flowed over the coating).

[0105] A shift in the resonant frequency of a crystal resonator refers to a change in the resonant frequency of the crystal resonator.

[0106] The device or quartz crystal microbalance may be configured to determine information indicative of the amount of etching of the coating by the liquid from the shift in the resonant frequency of the quartz crystal resonator. For example, the device or quartz crystal microbalance may include a controller or processor configured to determine information indicative of the amount of etching of the coating by the liquid from the shift in the resonant frequency of the quartz crystal resonator.

[0107] As mentioned above, the resonant frequency of a quartz crystal resonator depends on the mass per unit area of ​​the coating on the quartz crystal resonator. Therefore, if the coating on the quartz crystal resonator is etched and the mass per unit area of ​​the coating is reduced, the resonant frequency of the quartz crystal resonator will shift.

[0108] The device or quartz crystal microbalance (eg, a controller for the device or quartz crystal microbalance) may be configured to determine the amount of etching of the coating by the liquid from a shift in the resonant frequency of the quartz crystal resonator.

[0109] The device or quartz crystal microbalance may be configured to monitor etching of the coating by the liquid based on or from a shift in the resonant frequency of the quartz crystal resonator. For example, the device or quartz crystal microbalance may include a controller or processor configured to monitor etching of the coating by the liquid based on or from a shift in the resonant frequency of the quartz crystal resonator.

[0110] The device or quartz crystal microbalance (e.g., a controller or processor of the device or quartz crystal microbalance) may be configured to determine the etch rate of the coating, or the loss of mass per unit area of ​​the coating, or the loss of mass of the coating, or the loss of thickness of the coating based on the shift in the resonant frequency of the quartz crystal resonator.

[0111] The device or quartz crystal microbalance may be configured to detect whether etching of the coating has occurred based on the resonant frequency of the quartz crystal resonator, for example, the device or quartz crystal microbalance may be configured to determine that no etching has occurred if there is no shift in the resonant frequency of the quartz crystal resonator.

[0112] The apparatus may comprise a liquid source connected to the flow cell and configured to supply liquid to the flow cell. The liquid source may contain and / or store and / or hold the liquid.

[0113] The liquid source may include a liquid contained and / or stored and / or held in the liquid source.

[0114] The liquid may be or include an etchant or etching chemical.

[0115] The liquid may be configured to etch the coating.

[0116] The liquid may be configured to etch the material of the coating.

[0117] The liquid source may be or include a tank or vessel.

[0118] The apparatus may include a first liquid source connected to the flow cell to supply a first liquid to the flow cell, a second liquid source connected to the flow cell to supply a second liquid to the flow cell, and one or more valves for controlling the supply of the first liquid to the flow cell and the supply of the second liquid to the flow cell.

[0119] The apparatus may comprise a controller configured to control the operation of one or more valves to provide either the first liquid or the second liquid to the flow cell.

[0120] The first liquid may be a cleaning or rinsing liquid, such as deionized water.

[0121] The second liquid may be configured to etch the coating or the material of the coating.

[0122] The second liquid may be an etchant or etching chemical such as hydrofluoric acid, although of course other etching chemicals may be used instead, such as, for example, H2O2.

[0123] The etchant or chemical may be deionized.

[0124] The cleaning or rinsing fluid may be deionized.

[0125] The first liquid source may contain and / or store and / or hold the first liquid.

[0126] The second liquid source may contain and / or store and / or hold a second liquid.

[0127] The first liquid source and / or the second liquid source may be or comprise a tank or vessel.

[0128] The device (e.g., a controller or processor of the device) may be configured to control one or more valves to first supply a first liquid (e.g., a cleaning or rinsing liquid) to the flow cell for a predetermined period of time, followed by supplying a second liquid (e.g., an etching liquid or etching chemical) to the flow cell for a predetermined period of time, followed by supplying the first liquid to the flow cell for a predetermined period of time.

[0129] Alternatively, the apparatus may include a third fluid source connected to the flow cell for supplying a third liquid to the flow cell, and the one or more valves may control the supply of the third liquid to the flow cell for a predetermined period of time after the supply of the second liquid. For example, the third liquid may be a rinse liquid that is different from the first liquid.

[0130] The device, or quartz crystal microbalance, may comprise a holder that holds or is configured to hold a quartz crystal resonator.

[0131] The holder may hold the quartz crystal resonator with the coating of the quartz crystal resonator exposed and / or accessible.

[0132] The first aspect of the present invention may alternatively be referred to as a device or a system rather than an apparatus.

[0133] An application or use of the apparatus of the first aspect of the invention may be to monitor or investigate etching of material on the surface of a wafer during processing of the wafer, for example during semiconductor device fabrication.

[0134] An application or use of the apparatus according to the first aspect of the invention may be to determine the etch amount or etch rate of an etchant that is subsequently used to etch material on a surface of a wafer during processing of the wafer, for example during semiconductor device fabrication.

[0135] According to a second aspect of the present invention, there is provided a wafer processing apparatus comprising a liquid dispenser for dispensing liquid onto a surface of a wafer, a liquid supply for supplying liquid from a liquid source to the liquid dispenser, and an apparatus according to the first aspect of the present invention, wherein the flow cell is connected to the liquid source or liquid supply.

[0136] It is therefore also possible to supply the same liquid to the flow cell of the apparatus according to the first aspect of the invention that is dispensed onto the surface of the wafer, and therefore if the material of the coating is the same as the material of the surface of the wafer and the liquid is an etchant configured to etch the material, the amount or rate of etching of the coating may be the same as, related to or correspond to the amount or rate of etching of the material of the surface of the wafer.

[0137] Thus, by monitoring the etching of the coating, it may be possible to indirectly monitor and / or predict the etching of material on the surface of the wafer.

[0138] The second aspect of the invention may have any one of the following optional features, or any combination where compatible.

[0139] The second aspect of the invention may have any of the features of the first aspect of the invention, unless inconsistent.

[0140] Wafer processing equipment may refer to any equipment configured to process wafers.

[0141] Wafer processing equipment may be configured to etch material on the surface of the wafer by dispensing an etchant or etching chemical onto the surface of the wafer.

[0142] The liquid dispenser may include a nozzle for dispensing the liquid onto the surface of the wafer.

[0143] The nozzle may be positioned, located or provided on an arm of the wafer processing device.

[0144] The arm may be pivotally mounted so that the position of the nozzle relative to the wafer can be changed.

[0145] The wafer processing equipment may include a support or chuck for supporting or holding the wafer.

[0146] The support or chuck may be rotatable.

[0147] Typically, a support or chuck supports the wafer from below while liquid is dispensed onto the wafer from above, i.e., onto the top surface of the wafer.

[0148] The liquid source may be a container or tank that holds a quantity of liquid, or it may be a channel, tube, or passageway that delivers liquid to a liquid supply in the wafer processing system.

[0149] The liquid source may be external to the wafer processing apparatus and therefore not part of the wafer processing apparatus, or the wafer processing apparatus may include the liquid source.

[0150] The liquid supply may comprise one or more channels, tubes or passages for supplying liquid to the liquid dispenser.

[0151] There may be multiple different liquid sources to supply different liquids to the liquid dispensers, for example cleaning or rinsing liquids and etching liquids.

[0152] A single liquid supply may be connected to each of several different liquid sources to supply different liquids to the liquid dispenser, or there may be several liquid supplies to supply liquid from the liquid sources to the liquid dispenser.

[0153] There may be multiple liquid dispensers, for example a different liquid dispenser may be used for each different liquid supplied from each liquid source.

[0154] If there are multiple liquid supplies and / or sources, the flow cell may be connected to each of the liquid sources and / or supplies.

[0155] A flow cell connected to a liquid source or supply means that liquid can be supplied to the flow cell so that the liquid flows over the coating. Thus, the connection is a fluid or liquid connection.

[0156] The flow cell may be connected to a liquid source via a recirculation loop between the liquid source and the flow cell.

[0157] The device may include a valve for controlling the supply of liquid to the flow cell.

[0158] For example, the liquid source may be a tank or container of liquid, and the flow cell may be connected to the tank or container via a recirculation loop between the tank or container and the flow cell.

[0159] The flow cell may be connected to a liquid supply in series with the liquid dispenser or in parallel with the liquid dispenser.

[0160] Liquid discharged from the flow cell may be recovered and / or reused and / or recycled, for example, by returning it to a liquid source and / or liquid supply. For example, the device may include a recovery line connecting the output of the flow cell to a liquid source and / or liquid supply. Alternatively, liquid discharged from the flow cell may be collected or discarded.

[0161] The wafer processing device (eg, a controller for the device) may be configured to dispense liquid from a liquid dispenser onto the surface of the wafer and simultaneously supply liquid to the flow cell.

[0162] Thus, while the liquid is being dispensed onto the surface of the wafer, the liquid is also supplied to the flow cell and flows over the coating, and therefore the amount of etching of the coating can be the same as, related to, or correspond to the amount of etching of the material on the surface of the wafer.

[0163] For example, the wafer processing device may include one or more valves for controlling the distribution of liquid onto the surface of the wafer and for supplying liquid to the flow cell. The wafer processing device may further include a controller or processor for controlling the operation of the one or more valves to control the distribution of liquid onto the surface of the wafer and the supply of liquid to the flow cell.

[0164] Alternatively, the wafer processing apparatus (eg, a controller for the apparatus) may be configured to supply liquid to the flow cell independently or separately from the dispensing of liquid from the liquid dispenser onto the surface of the wafer.

[0165] The wafer processing device (e.g., a quartz crystal microbalance) may be configured to determine, calculate, or estimate information indicative of the amount of etching of the coating from the shift in the resonant frequency of the quartz crystal resonator. For example, the information indicative of the amount of etching of the coating may be the etch rate of the coating or the amount of etching of the coating.

[0166] The wafer processing device may be configured to control and / or modify subsequent dispensing of liquid onto the surface of the wafer based on information indicative of the amount of etching of the coating. For example, the wafer processing device may control the amount of liquid dispensed onto the surface of the wafer or the duration for which liquid is dispensed onto the surface of the wafer based on information indicative of the amount of etching of the coating.

[0167] For example, the wafer processing device may be configured to determine the etch rate of the coating with the liquid. The wafer processing device may then control and / or modify the subsequent dispensing of the liquid onto the surface of the wafer based on the determined etch rate. For example, the wafer processing device may control the amount of liquid dispensed onto the surface of the wafer or the duration for which the liquid is dispensed onto the surface of the wafer.

[0168] The material of the coating may be the same as the material of the surface of the wafer.

[0169] The surface of the wafer may have a coating or layer of the same material as the coating of the quartz resonator. The liquid may be an etchant or etching chemical configured to etch the material; The term etchant or etching chemical may refer to a liquid or chemical configured to etch a coating.

[0170] The wafer processing apparatus (eg, a controller for the apparatus) may be configured to determine, calculate, or estimate information indicative of the amount of etching of material on the surface of the wafer from the shift in the resonant frequency of the quartz resonator.

[0171] The wafer processing apparatus (eg, a controller of the apparatus) may be configured to monitor etching of material on the surface of the wafer based on or from a shift in the resonant frequency of the quartz resonator.

[0172] The wafer processing apparatus (e.g., a controller of the apparatus) may be configured to determine, calculate, or estimate an etch rate of the material on the surface of the wafer, or a mass loss per unit area of ​​the material on the surface of the wafer, or a mass loss of the material on the surface of the wafer, or a thickness loss of the material on the surface of the wafer based on the shift in the resonant frequency of the quartz resonator.

[0173] The wafer processing device (eg, a controller or processor of the wafer processing device) may be configured to control the operation of the liquid dispenser based on the shift in the resonant frequency of the crystal resonator.

[0174] The wafer processing device (eg, a controller or processor of the wafer processing device) may be configured to control operation of the wafer processing device based on the shift in the resonant frequency of the crystal resonator.

[0175] For example, when a desired or predetermined amount of etching of the coating has been determined, the wafer processing apparatus may be configured to stop dispensing liquid by the liquid dispenser.

[0176] The wafer processing device (e.g., a controller or processor of the wafer processing device) may be configured to determine whether a desired or predetermined shift in the resonant frequency of the quartz resonator has occurred, and to stop dispensing liquid onto the surface of the wafer when it is determined that the desired or predetermined shift in the resonant frequency of the quartz resonator has occurred.

[0177] According to a third aspect of the present invention, there is provided a method comprising using a flow cell to flow a liquid over a coating on a quartz resonator of a quartz crystal microbalance.

[0178] The method according to the third aspect of the invention may have any of the features of the first and / or second aspect of the invention, unless inconsistent.

[0179] The method according to the third aspect of the invention may be carried out using an apparatus according to the first aspect of the invention or a wafer processing apparatus according to the second aspect of the invention.

[0180] The third aspect of the invention may have any one of the following optional features, or any combination where compatible.

[0181] The liquid may be configured to etch the coating.

[0182] The method may include detecting or determining whether the coating is etched by the liquid.

[0183] The method may include monitoring or studying the etching of the coating by the liquid.

[0184] The coating is SiO2, or Al2O3, or TiN, or Cu, or W, or Si, or Si3N4, or TaN, or Co, or SiO x , or W-doped C, or Co, or SnO x , or C, or SiC x N v may include one or more of:

[0185] The liquid may include hydrofluoric acid, although of course other etching chemistries may be used instead, such as, for example, H2O2.

[0186] The liquid may include one or more of hydrofluoric acid, or H2O2, or HNO3, or HNO3 and HF, or DIO3, or NH4OH, or HCl.

[0187] The liquid may be deionized.

[0188] The method may include detecting a resonant frequency, such as a fundamental resonant frequency, of the crystal resonator.

[0189] The method may include determining a shift or change in the resonant frequency of the quartz resonator. The resonant frequency may be a resonant frequency such as a fundamental resonant frequency. In particular, as described above, etching of the coating by the liquid reduces the mass per unit area of ​​the coating, thus causing a shift in the resonant frequency of the quartz resonator. Therefore, etching of the coating can be monitored by determining the shift or change in the resonant frequency of the quartz resonator.

[0190] The method may include determining information indicative of an amount of etching of the coating by the liquid from a shift in the resonant frequency of the quartz crystal resonator.

[0191] The method may include monitoring etching of the coating by the liquid based on or from a shift in the resonant frequency of the quartz resonator.

[0192] The method may include determining or calculating an etch rate of the coating, or a mass loss per unit area of ​​the coating, or a mass loss of the coating, or a thickness loss of the coating based on the shift in the resonant frequency of the quartz resonator.

[0193] The method may be, for example, a method for monitoring or controlling wafer etching, or wafer processing, or semiconductor device fabrication.

[0194] The method may include dispensing a liquid onto a surface of the wafer, the surface of the wafer comprising the same material as the material of the coating. For example, the wafer may include a layer or coating of material on the surface of the wafer.

[0195] The method may include controlling and / or modifying the distribution of liquid onto the surface of the wafer based on the calculated etch rate of the coating, or the reduction in mass per unit area of ​​the coating, or the reduction in mass of the coating, or the reduction in thickness of the coating. For example, the method may include controlling the amount of liquid dispensed onto the surface of the wafer or the duration for which the liquid is dispensed onto the surface of the wafer.

[0196] The method may simultaneously include dispensing a liquid onto a surface of the wafer, the surface of the wafer comprising the same material as the material of the coating. For example, the wafer may include a layer or coating of material on the surface of the wafer.

[0197] The method may include determining, calculating, or estimating information indicative of an amount of etching of material on the surface of the wafer from a shift in a resonant frequency of the quartz crystal resonator. The resonant frequency may be a resonant frequency such as a fundamental resonant frequency.

[0198] The method may include determining, calculating, or estimating an etch rate of the material at the surface of the wafer, or a mass loss per unit area of ​​the material at the surface of the wafer, or a mass loss of the material at the surface of the wafer, or a thickness loss of the material at the surface of the wafer based on the shift in resonant frequency of the quartz resonator.

[0199] The method may include controlling dispensing of liquid onto the surface of the wafer based on a shift in a resonant frequency of the quartz resonator. The resonant frequency may be a resonant frequency, such as a fundamental resonant frequency. For example, the method may include determining whether a desired or predetermined shift in the resonant frequency of the quartz resonator has occurred, and stopping dispensing of liquid onto the surface of the wafer when it is determined that the desired or predetermined shift in the resonant frequency of the quartz resonator has occurred.

[0200] The method may include flowing a cleaning or rinsing liquid over the coating on the quartz resonator, followed by flowing a liquid configured to etch the coating over the coating on the quartz resonator, followed by flowing the cleaning or rinsing liquid over the coating on the quartz resonator.

[0201] The method may include detecting a first resonant frequency of the quartz crystal resonator while flowing a cleaning or rinsing liquid over the coating on the quartz crystal resonator before the liquid configured to etch the coating, detecting a second resonant frequency of the quartz crystal resonator while flowing a cleaning or rinsing liquid over the coating on the quartz crystal resonator after the liquid configured to etch the coating, and determining a shift of the resonant frequency of the quartz crystal resonator from the first resonant frequency and the second resonant frequency. The resonant frequency may be a fundamental resonant frequency.

[0202] The method may include performing a first etching step in which an etching solution is flowed over the coating to etch the coating, determining whether a resonant frequency of the quartz crystal resonator is greater than or equal to a predetermined resonant frequency, and if not, performing a second etching step in which an etching solution is flowed over the coating to etch the coating.

[0203] The method may include monitoring the etching of the coating with a liquid and subsequently controlling or modifying the distribution of the same liquid onto the surface of the wafer based on the results of the monitoring.

[0204] For example, the method may include determining an etch rate or amount of etching of a coating with a liquid, and then controlling or modifying the distribution of the same liquid onto the surface of the wafer based on the determined etch rate or amount of etching of the coating.

[0205] The present invention includes combinations of the described embodiments and preferred features except where such combinations are expressly not permitted or explicitly avoided. [Brief explanation of the drawings]

[0206] BRIEF DESCRIPTION OF THE DRAWINGS Embodiments and experiments illustrating the principles of the present invention will now be described with reference to the accompanying figures.

[0207] [Figure 1] FIG. 1 is a simplified schematic diagram of a quartz crystal resonator used in a quartz crystal microbalance.

[0208] [Figure 2] Figure 2 is a simplified schematic diagram of a quartz crystal microbalance.

[0209] [Figure 3] FIG. 3 is a simplified schematic diagram of an oscillator circuit for detecting the resonant frequency of a quartz crystal resonator that may be used in a quartz crystal microbalance.

[0210] [Figure 4] FIG. 4 is a schematic diagram of an apparatus according to one embodiment of the present invention.

[0211] [Figure 5] FIG. 5 is a schematic diagram of an apparatus according to one embodiment of the present invention.

[0212] [Figure 6] FIG. 6 is a schematic diagram of an apparatus according to one embodiment of the present invention.

[0213] [Figure 7] FIG. 7 is a schematic diagram of measurement results according to one embodiment of the present invention.

[0214] [Figure 8] FIG. 8 is a schematic diagram of an apparatus according to one embodiment of the present invention.

[0215] [Figure 9]FIG. 9 is a schematic diagram of an apparatus according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0216] Aspects and embodiments of the present invention will now be described with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0217] Embodiments of the invention may include any of the features of Figures 1-3, for example, as described above.

[0218] Figure 4 is a schematic diagram of an apparatus according to one embodiment of the present invention. As shown in Figure 4, apparatus 11 includes a flow cell 13. Flow cell 13 includes a tube 15 or flow chamber through which a liquid can flow, as indicated by arrow 17. In addition, flow cell 13 includes an opening 19 or window in the side (e.g., circumferential surface) of tube 15.

[0219] The apparatus 11 further includes a quartz crystal microbalance 2. The quartz crystal microbalance 2 may have, for example, any of the features of the quartz crystal microbalance 2 described above and / or shown in FIGS. 1-3. Specifically, the quartz crystal microbalance 2 includes a quartz crystal resonator 1. The quartz crystal resonator 1 may have, for example, any of the features of the quartz crystal resonator 1 described above and / or shown in FIGS. 1-3. Specifically, the quartz crystal resonator 1 includes a quartz crystal wafer 3. The quartz crystal wafer 3 may be cut from a bulk quartz crystal with a specific orientation appropriate to the crystal axes of the bulk quartz crystal. For example, the quartz crystal wafer 3 may be an AT-cut quartz crystal wafer. The quartz crystal wafer 3 is sandwiched between a pair of electrodes 5 and 7, as shown in FIG. 1. In particular, a first electrode 5 is provided on a first (e.g., top) surface of the quartz crystal wafer 3, and a second electrode 7 is provided on a second (e.g., bottom) surface of the quartz crystal wafer 3. The electrodes 5 and 7 are not shown in FIG. 4 for simplicity.

[0220] Electrodes 5 and 7 may, for example, comprise or be made of gold.

[0221] The quartz crystal wafer 3 may be, for example, disk-shaped.

[0222] The quartz crystal wafer may have a thickness of 100 μm to 500 μm, for example 330 μm.

[0223] Although not shown in FIG. 4 for simplicity, the quartz crystal microbalance 2 further includes a controller 4 and crystal oscillator electronics 6, as shown in FIG. 2. The crystal oscillator electronics 6 is electrically connected to the crystal resonator 1 and configured to drive oscillation of the crystal resonator 1, for example, by applying an alternating current and / or voltage to first and second electrodes 5 and 7 of the crystal resonator 1. The controller 4 is electrically connected to the crystal oscillator electronics 6 and configured to control the operation of the crystal oscillator electronics 6 to drive oscillation of the crystal resonator 1 and to detect the resonant frequency of the crystal resonator 1, for example, the fundamental resonant frequency of the crystal resonator 1.

[0224] The quartz crystal microbalance 2 may further comprise an oscillator circuit as shown in Figure 3 and described above for detecting the resonant frequency of the quartz crystal resonator 1. Of course, other types of oscillator circuits may alternatively be used for detecting the resonant frequency of the quartz crystal resonator 1.

[0225] 4, a coating 23 is provided on the surface (main surface) of the quartz wafer 3. As will be explained below, the coating may be made of a variety of different materials, such as SiO2, or Al2O3, or TiN, or Cu, or W, or Si, or Si3N4, or TaN, or Co, or SiO x , or W-doped C, or Co, or SnO x , or C, or SiC x N v The coating 23 is a layer of material on the surface of the quartz wafer 3.

[0226] The coating 23 may have a thickness of, for example, 0.5 μm or more. The coating may have a thickness of, for example, 3 μm or less.

[0227] The coating 23 may cover all or part of the major surface of the quartz wafer 3. In this embodiment, the coating 23 is formed only on the major surface of the quartz wafer 3.

[0228] In this embodiment, the first electrode 5 is formed on the top surface of the crystal wafer 3 so as to cover only a portion of the top surface of the crystal wafer 3, and the coating 23 is formed on another portion of the top surface of the crystal wafer 3 so as to cover another portion of the top surface of the crystal wafer 3. In other words, the first electrode 5 and the coating 23 are provided on different portions of the top surface of the crystal wafer 3. This is not shown in FIG. 4 for simplicity. As shown in FIG. 4, the crystal resonator 1 is held and / or supported by a holder 25. In particular, the holder 25 holds the crystal resonator 1 so that the coating 23 provided on the surface of the crystal wafer 3 is exposed. Specifically, the coating 23 is on the first main surface of the crystal wafer 3, and the holder 25 holds the crystal resonator 1 from the second main surface of the crystal wafer 3.

[0229] In particular, coating 23 is formed on the top surface of quartz wafer 3, and the bottom surface of quartz wafer 3 is received in holder 25, so that coating 23 is exposed and / or accessible.

[0230] The holder 25 is positioned in the opening 19 in the side of the tube 15 so that the coating 23 is exposed to the liquid flowing along the tube 15. Thus, as the liquid flows along the tube 15, the liquid contacts and flows over the coating 23.

[0231] In particular, the holder 25 , and therefore the quartz crystal resonator 1 held by the holder 25 , is received in the opening 19 in the side of the tube 15 with the coating 23 positioned facing the inside of the tube 15 .

[0232] Thus, when a liquid configured to etch the material of coating 23 flows along tube 15, the liquid comes into contact with and flows over coating 23, causing coating 23 to be etched by the liquid.

[0233] 4 can be used to study or monitor the etching of coating 23 as a liquid configured to etch coating 23 flows through tube 15. For example, the liquid may be hydrofluoric acid, or another etchant, or a chemical such as H2O2.

[0234] In particular, the quartz crystal microbalance 2 can be used to measure the reduction in mass per unit area of ​​the coating 23 on the surface of the quartz crystal wafer 3 due to etching by measuring the change in the oscillation frequency of the quartz crystal resonator 1 (or the quartz crystal resonator wafer 3) caused by the change in mass per unit area of ​​the coating 23 due to etching. Specifically, as described above, the resonant frequency of the quartz crystal resonator 1 depends on the mass per unit area at the surface of the quartz crystal resonator 1. Therefore, a change in the mass per unit area at the surface of the quartz crystal resonator 1 causes a shift (change) in the resonant frequency of the quartz crystal resonator 1. Therefore, by measuring the shift in the resonant frequency of the quartz crystal resonator 1, the change in mass per unit area at the surface of the quartz crystal resonator 1 can be determined, e.g., calculated.

[0235] In particular, a reduction in the mass per unit area of ​​the coating 23 may cause the resonant frequency of the quartz crystal resonator 1 to increase.

[0236] Quartz crystal microbalance 2 is 1ng / cm 2 The sensitivity can be as high as 27 ng / cm for changes in mass per unit area. Typically, this corresponds to a change in thickness of the coating of 0.01 nm (0.1 Å) or less. For example, a change in thickness of 0.1 nm (1 Å) in SiO2 requires a mass per unit area of ​​27 ng / cm.2 To change the thickness of Al2O3 by 0.1 nm (1 Å), the mass per unit area must be reduced by 40 ng / cm 2 To change the thickness of TiN by 0.1 nm (1 Å), the mass per unit area must be reduced by 54 ng / cm 2 It needs to be reduced.

[0237] The thickness of the coating 23 may be 3 μm or less, and such a thickness of the coating 23 may not significantly affect the sensitivity of the quartz crystal microbalance 2.

[0238] Assuming that a typical etching cycle removes about 100 Å of coating 23, this means that about 300 etching cycles can be monitored using a 3 μm thick coating 23.

[0239] The apparatus may include one or more heaters or coolers for controlling the temperature of the quartz wafer 3 and / or the flow cell 13 and / or the liquid within the flow cell 13. In addition, the apparatus may include one or more temperature sensors for sensing the temperature of the quartz wafer 3 and / or the flow cell 13 and / or the liquid within the flow cell 13. The apparatus may further include a controller configured to control the one or more heaters or coolers based on the output of the one or more temperature sensors. In particular, the controller may be configured to control the one or more heaters or coolers to maintain the temperature of the quartz wafer 3 and / or the flow cell 13 and / or the liquid within the flow cell 13 constant or substantially constant.

[0240] The resonant frequency of the quartz resonator can be detected using a flow cell and the outlet of the flow cell at a predetermined or fixed height, which can prevent pressure fluctuations due to height changes from affecting the detection of the resonant frequency.

[0241] The quartz crystal wafer 3 may be configured to have a fundamental resonant frequency of, for example, about 5 MHz or in the order of 5 MHz.

[0242] The quartz wafer 3 may have a diameter of, for example, about 25 mm, or about 25 mm, or 25 mm. Alternatively, the quartz wafer may have a diameter of, for example, about 14 mm, or about 14 mm, or 14 mm.

[0243] 5 is a schematic diagram of an apparatus according to a second embodiment of the present invention. As shown in FIG. 5, the apparatus 27 includes a flow cell 29 having a different configuration from the flow cell 13 shown in FIG.

[0244] 5, flow cell 29 includes an inlet 31 for connecting flow cell 29 to a liquid supply, so that liquid can enter flow cell 29 via inlet 31. Flow cell 29 further includes an outlet 33 for connecting flow cell 29 to an external flow path 35 (e.g., tubing), so that liquid can exit flow cell 29 via outlet 33. The outlet may be directly or indirectly connected to a liquid supply, so that liquid exiting flow cell 29 can be recirculated and reused.

[0245] Additionally, the flow cell 29 includes a flow chamber 37 or flow path connected to the inlet 31 and outlet 33, allowing a liquid to flow from the inlet 31 to the outlet 33 through the flow chamber 37. The flow chamber 37 is positioned to bring the liquid into contact with the coating 23 on the quartz crystal wafer 3 of the quartz crystal resonator 1 of the quartz crystal microbalance and to cause the liquid to flow over the coating 23.

[0246] 5, the quartz crystal resonator 1 of the quartz crystal microbalance is received or housed in a flow cell 29. For example, the flow cell 29 may include a space or cavity capable of receiving the quartz crystal wafer 3. The flow cell 29 may include one or more holes or openings through which wires can pass to connect to the electrodes of the quartz crystal resonator 1.

[0247] The quartz crystal resonator 1, coating 23, and quartz crystal microbalance of this embodiment may have any of the features of the quartz crystal resonator 1, coating 23, and quartz crystal microbalance 2 of the first embodiment described above or shown in any of Figures 1-4, unless inconsistent. Although not shown, the quartz crystal resonator 1 includes electrodes 5 and 7 on the quartz crystal wafer 3, as shown in Figure 1. In addition, the quartz crystal microbalance includes the controller 4 and crystal oscillator electronics 6 shown in Figure 2 and described above. The quartz crystal microbalance may further include an oscillator circuit shown in Figure 3 and described above to detect the resonant frequency of the quartz crystal resonator 1. Of course, other types of oscillator circuits may alternatively be used to detect the resonant frequency of the quartz crystal resonator 1. Therefore, for the sake of brevity, a description of these features will not be repeated here.

[0248] The flow chamber 37 of the flow cell is positioned so that the flow chamber 37, or a portion of the flow chamber 37, is adjacent to the coating 23 so that liquid flowing through the flow chamber 37 contacts and flows over the coating 23.

[0249] Flow chamber 37, or a portion of flow chamber 37, has an open side facing coating 23 so that liquid flowing through the flow chamber can contact coating 23.

[0250] Flow chamber 37, or a portion of flow chamber 37, may be disc-shaped so that the liquid contacts coating 23 in a circular area or region on the top surface of coating 23.

[0251] Flow cell 29 is made of or includes a material that is not etched by the etching solution. For example, the flow cell may be made of or include polytetrafluoroethylene (PTFE). Generally, the flow cell is made of or includes a chemically inert material. In particular, flow cell 29 includes a material that is inert to and / or compatible with liquids, such as etching solutions or etching chemicals, that are supplied to the flow cell.

[0252] The volume of flow chamber 37 (e.g., from the inlet of flow chamber 37 to the outlet of flow chamber 37) may be 10 mL or less. The volume may be 0.1 mL or more. The volume may be 0.1 mL or more and 10 mL or less. In certain embodiments, the volume may be 1 mL or more and 2 mL or less, for example, 1.0 mL or more and 2.0 mL or less, for example, about 1 mL.

[0253] The volume of the region of the flow chamber 37 opposite (e.g., directly opposite) the area of ​​the quartz resonator in contact with the liquid may be 2 mL or less, e.g., 2.0 mL or less. The volume may be 0.05 mL or more. The volume may be 0.05 mL or more to 2 mL or 2.0 mL or less, e.g., about 0.15 mL.

[0254] The volume of the region of flow chamber 37, defined by the area of ​​the quartz crystal resonator in contact with the liquid multiplied by the distance between the quartz crystal resonator and the opposite surface of flow chamber 37, may be 2 mL or less, e.g., 2.0 mL or less. The volume may be 0.05 mL or more. The volume may be 0.05 mL or more to 2 mL or 2.0 mL or less, e.g., about 0.15 mL.

[0255] The distance between the area of ​​the quartz crystal resonator in contact with the liquid and the opposite surface of the flow chamber may be between 0.2 mm and 5 mm, for example about 2 mm.

[0256] The area of ​​the quartz crystal resonator in contact with the liquid is 0.1 cm 2 More than 10cm 2Below, for example, about 0.5 cm 2 may be.

[0257] Figure 6 shows the flow cell 29 of Figure 5 connected to a liquid supply. In particular, a first liquid container or tank (first liquid source) 39 containing a first liquid, and a second liquid container or tank (second liquid source) 41 containing a second liquid are both connected to the inlet 31 of the flow chamber 29 by respective flow paths. A first valve 43 is positioned in the flow path connecting the first liquid container 39 to the inlet 31, and a second valve 45 is positioned in the flow path connecting the second liquid container 41 to the inlet 31.

[0258] The first valve 43 can be opened to supply a first liquid to the inlet 31 of the flow cell 29 or closed to prevent the supply of the first liquid to the inlet 31. Similarly, the second valve 45 can be opened to supply a second liquid to the inlet 31 of the flow cell 29 or closed to prevent the supply of the second liquid to the inlet 31.

[0259] In this embodiment, the first liquid is a cleaning or rinsing liquid, such as deionized water, and the second liquid is an etching liquid or chemical, such as hydrofluoric acid. Of course, other etching chemicals, such as H2O2, may be used instead.

[0260] During operation of the apparatus, the first valve 43 is set to open and the second valve 45 is set to closed, thereby allowing a cleaning or rinsing liquid to be supplied to the flow cell 29. The cleaning or rinsing liquid thus flows through the flow chamber 37 across the coating 23, cleaning or rinsing the coating 23. This is sometimes referred to as the first cleaning or rinsing step.

[0261] Subsequently, the first valve 43 is set to closed and the second valve 45 is set to open, thereby allowing the etching solution to be supplied to the flow cell 29. The etching solution thus flows through the flow chamber 37 across the coating 23, etching the coating and thereby changing the mass per unit area of ​​the coating 23, thereby changing the resonant frequency of the quartz crystal resonator 1. This is sometimes referred to as the etching step.

[0262] Subsequently, the first valve 43 is set to open and the second valve 45 is set to closed, thereby allowing a cleaning or rinsing liquid to be supplied to the flow cell 29. The cleaning or rinsing liquid thus flows through the flow chamber 37 across the coating 23, cleaning or rinsing the coating 23. This is sometimes referred to as a second cleaning or rinsing step.

[0263] The apparatus may comprise a controller 47 configured to control the opening and closing of the first valve 43 and the second valve 45 and to control the supply of the first and second liquids to the flow cell 29 .

[0264] FIG. 7 shows an example of measurement data obtained during operation of the above-described device.

[0265] Regions A and C in Figure 7 correspond to the first and second cleaning or rinsing steps, respectively. Region B in Figure 7 corresponds to the etching step.

[0266] 7, during the first cleaning or rinsing step, in which only cleaning or rinsing liquid is supplied to the flow cell 29, the resonant frequency of the quartz resonator 1 is determined to be 5 MHZ. This resonant frequency is determined by the properties of the quartz wafer 3 and by the properties of the coating 23 (i.e., the mass per unit area of ​​the coating 23).

[0267] As shown in FIG. 7, during the subsequent etching step, when the cleaning or rinsing fluid in the flow cell 29 is replaced by the etching fluid, the resonant frequency initially decreases due to the different densities and viscosities of the cleaning or rinsing fluid and the etching fluid.

[0268] When the etching solution is supplied to the flow cell 29, the etching solution etches the coating 23, removing a portion of the coating 23 and thus reducing the mass per unit area of ​​the coating 23. The gradual reduction in the mass per unit area of ​​the coating 23 gradually increases the resonant frequency of the quartz crystal resonator 1, as shown in FIG.

[0269] As shown in Figure 7, during the subsequent second cleaning or rinsing step, when the etching solution in the flow cell 29 is replaced with a cleaning or rinsing solution, the resonant frequency initially increases due to the different densities and viscosities of the cleaning or rinsing solution and the etching solution, and then settles to a stable value as shown in Figure 5.

[0270] As shown in FIG. 5, the stable value of the resonant frequency in the second cleaning or rinsing step is higher than the stable value of the resonant frequency in the first cleaning or rinsing step because the coating 23 is etched between the first and second cleaning or rinsing steps, resulting in a smaller mass per unit area of ​​the coating 23 in the second cleaning or rinsing step than in the first cleaning or rinsing step.

[0271] By measuring the shift or change in resonant frequency between the first cleaning or rinsing step and the second cleaning or rinsing step, the change in mass per unit area of ​​coating 23 due to etching can be determined or calculated. Thus, the amount of coating 23 etched by the etching solution can be determined, and etching can thus be monitored. For example, the etching rate of coating 23 by the liquid can be calculated.

[0272] Alternatively, instead of comparing the resonant frequency of the quartz wafer 3 between the first cleaning or rinsing step and the second cleaning or rinsing step, the resonant frequency of the quartz wafer 3 at the start of the etching step while the etching solution is being supplied to the flow cell 29 can be compared with the resonant frequency of the quartz wafer 3 at the end of the etching step while the etching solution is being supplied to the flow cell 29. In other words, the shift in the resonant frequency of the quartz wafer can be determined between the resonant frequency near the start of region B in FIG. 5 and the resonant frequency near the end of region B in FIG. 5.

[0273] In practice, after transitioning from a cleaning or rinsing solution to an etching solution, and from an etching solution to a cleaning or rinsing solution, it may take a longer period of time than shown in Figure 5 for the measured resonant frequency to settle to a stable value. For example, a stabilization time of several minutes may be required.

[0274] Alternatively, the first resonant frequency of the quartz resonator 1 can be measured while the quartz resonator 1 is drying. For example, the initial resonant frequency of the quartz resonator 1 can be measured in a dry state, i.e., when no liquid is applied to the coating 23. Next, an etching liquid can be applied to the coating 23 on the quartz wafer 3 to etch the coating 23. Subsequently, the quartz resonator 1 can be dried, and the second resonant frequency of the quartz resonator 1 can be measured while the quartz resonator 1 is drying. Additionally, a cleaning or rinsing liquid can be applied to the coating 23 after and / or before applying the etching liquid to the coating 23.

[0275] The quartz resonator 1 and / or coating 23 may be dried by supplying a gas, such as N2, to the quartz resonator 1 and / or coating 23 to dry the coating. For example, the gas may be provided using one of the liquid supply paths shown in Figure 6, or by an additional gas supply path connected to a gas container or tank. The apparatus may include a valve for controlling the supply of gas to the quartz resonator 1 and / or coating 23.

[0276] Of course, in other embodiments of the present invention, flow cells of different configurations may be used in place of the flow cells 13 and 29 of the first and second embodiments.

[0277] The apparatus of the present invention may be used or applied to monitor etching of material on the surface of a wafer during processing of the wafer, for example, during semiconductor device fabrication.

[0278] FIG. 8 is a schematic diagram of an apparatus according to one embodiment of the present invention.

[0279] 8, the wafer processing apparatus 49 according to this embodiment includes a liquid dispenser 51 for dispensing a liquid onto the surface of the wafer W. The wafer processing apparatus 49 is for etching material on the surface of the wafer W by dispensing an etching liquid onto the surface of the wafer W. The etching liquid is configured to etch the material on the surface of the wafer W.

[0280] As shown in FIG. 8, the wafer processing apparatus 49 includes a liquid source 53 and a liquid supply unit 55 for supplying liquid from the liquid source 53 to the liquid dispenser 51 .

[0281] For example, the liquid source 53 may be a container or tank of liquid, or may be a channel, tube, or passageway that supplies liquid to the liquid supply 55 of the wafer processing device 49.

[0282] The liquid supply 55 comprises a flow path, eg, a tube or passageway, configured to supply liquid from the liquid source 53 to the liquid dispenser 51 .

[0283] The liquid source 53 may be external to, and therefore not part of, the wafer processing apparatus 49. Alternatively, the wafer processing apparatus 49 may include the liquid source 53.

[0284] The liquid supply 55 includes a valve 57 for controlling the supply of liquid from the liquid source 53 to the liquid dispenser 51 through the liquid supply 55. In particular, the valve 57 can be opened to allow liquid to be supplied from the liquid source 53 to the liquid dispenser 51, or closed to prevent liquid from being supplied from the liquid source 53 to the liquid dispenser 51.

[0285] The operation of the valve 57 may be controlled by the controller 47 of the wafer processing device 49 .

[0286] Controller 47 can control apparatus 49 to perform an etching cycle in which valve 57 is opened for a predetermined period of time, thereby supplying etching liquid from liquid source 53 to liquid dispenser 51 and dispensing it onto the surface of wafer W for a predetermined period of time. The etching liquid is configured to etch material on the surface of the wafer.

[0287] In addition, wafer processing apparatus 49 further includes apparatus 27 of the second embodiment described above. Of course, apparatus 11 of the first embodiment described above could be used in place of apparatus 27 of the second embodiment, or a flow cell with a different configuration than the flow cell used in either the first or second embodiment could be used.

[0288] As shown in Figure 8, the device 27 of the second embodiment is connected to a liquid supply 55. In particular, a flow path branches off from the liquid supply 55 and is connected to the device 27. In particular, the inlet 31 of the flow cell 29 is connected to the liquid supply 55. In Figure 8, liquid is supplied simultaneously to the device 27 and the liquid dispenser 51 when the valve 57 is open. However, in other embodiments, one or more additional valves may be provided and / or the valve 57 may be moved so that the supply of liquid to the device 27 can be controlled independently of the supply of liquid to the liquid dispenser 51.

[0289] In the embodiment of FIG. 8, etching liquid is supplied from liquid source 53 to liquid dispenser 51 and dispensed onto the wafer, while etching liquid is supplied from liquid supply 53 to flow chamber 37 of flow cell 29, where it is flowed across coating 23 on quartz wafer 3, etching coating 23.

[0290] Of course, alternatively, the device 27 may be connected directly to the liquid source 53 and a further valve may be provided to control the supply of liquid from the liquid source 53 to the device 27 .

[0291] The material of the coating 23 is selected to be the same as the material of the surface of the wafer W to be etched. Thus, when liquid is simultaneously applied to the wafer W and the coating 23, the coating 23 is etched at the same time as the material on the surface of the wafer W is etched.

[0292] In particular, because the material of coating 23 is the same as the material of the surface of wafer W, when coating 23 is exposed to a liquid in the same or a corresponding manner, the amount of etching of coating 23 by the liquid may be the same as, related to, or correspond to the amount of etching of the material on the surface of wafer W. Thus, by monitoring the etching of coating 23 as described above, it may be possible to indirectly monitor the etching of the material on the surface of wafer W.

[0293] Wafer processing device 49 (eg, controller 47) may be configured to determine, calculate, or estimate information indicative of the amount of etching of material on the surface of wafer W from the shift in the resonant frequency of the quartz resonator of device 27.

[0294] Wafer processing device 49 (eg, controller 47) may be configured to monitor etching of material on the surface of wafer W based on or from a shift in the resonant frequency of the quartz resonator of device 27.

[0295] The wafer processing device 49 (e.g., controller 47) may be configured to determine, calculate, or estimate the etch rate of the material on the surface of the wafer, or the mass loss per unit area of ​​the material on the surface of the wafer, or the mass loss of the material on the surface of the wafer, or the thickness loss of the material on the surface of the wafer, based on the shift in the resonant frequency of the quartz resonator of the device 27.

[0296] The wafer processing device (eg, controller 47) may be configured to control the operation of the liquid dispenser 51 or the wafer processing device based on the shift in the resonant frequency of the crystal resonator.

[0297] For example, when a desired or predetermined amount of etching of coating 23 has been determined, wafer processing device 49 (eg, controller 47) may be configured to stop dispensing liquid by liquid dispenser 51.

[0298] The wafer processing device 49 (e.g., controller 47) may be configured to determine whether a desired or predetermined shift in the resonant frequency of the quartz resonator has occurred, and to stop dispensing liquid onto the surface of the wafer when it is determined that a desired or predetermined shift in the resonant frequency of the quartz resonator has occurred.

[0299] The liquid dispenser 51 includes a nozzle for dispensing liquid onto the surface of the wafer. The nozzle is positioned, located, or provided on an arm of the wafer processing device 49. The arm is pivotally mounted so that the position of the nozzle relative to the wafer W can be changed.

[0300] The wafer processing apparatus includes a support or chuck 59 for supporting or holding the wafer. The support or chuck 59 may be rotatable.

[0301] As shown in FIG. 8, a support or chuck 59 supports the wafer W from below while liquid is dispensed onto the wafer from above, ie, onto the top surface of the wafer.

[0302] Although Figure 8 shows only a single liquid source 53, multiple liquid sources 53 may be provided. For example, similar to Figure 6, device 49 may include a first liquid source 53 and a second liquid source 53 with respective valves for supplying the first liquid and the second liquid, respectively, to liquid supplies 55. Alternatively, separate liquid supplies may be provided for each of the liquid sources to supply the respective liquids to liquid dispenser 51 and device 27.

[0303] Similar to the arrangement described with reference to Figure 6, the first liquid may be a cleaning or rinsing liquid and the second liquid may be an etching liquid.

[0304] Apparatus 49 may be controlled (e.g., by controller 47) to first simultaneously supply a cleaning or rinsing liquid to both liquid dispenser 51 and apparatus 27. Subsequently, apparatus 49 may then be controlled to simultaneously supply an etching liquid to both liquid dispenser 51 and apparatus 27. Subsequently, apparatus 49 may thirdly be controlled to simultaneously supply a cleaning or rinsing liquid to liquid dispenser 51 and apparatus 27. The above description of apparatus 27 in each of these steps applies equally to this embodiment.

[0305] A single liquid supply 55 may be connected to each of several different liquid sources to supply different liquids to the liquid dispenser 51. Alternatively, there may be several liquid supplies to supply liquid from the liquid sources to the liquid dispenser 51.

[0306] There may be multiple liquid dispensers 51. For example, a different liquid dispenser 51 may be used for each different liquid supplied from each liquid source.

[0307] In some embodiments, the apparatus can be controlled to supply liquid to apparatus 27 without supplying liquid to liquid dispenser 51. Based on the shift in the resonant frequency of the quartz resonator, the apparatus can determine the etch rate or amount of etching of the coating by the liquid. The apparatus can then use this information to control or modify the subsequent dispensing of liquid from liquid dispenser 51 onto the surface of wafer W. For example, the apparatus may control the amount of liquid dispensed onto the surface of wafer W and / or the duration for which liquid is dispensed onto the surface of wafer W based on the determined etch rate or amount.

[0308] Figure 9 shows a modified version of the device of Figure 8, in which device 27 is connected by a flow path directly to a liquid source 53. A valve 61 is provided in the flow path to control the supply of liquid from liquid source 53 to the device. Although not shown, the outlet of the device may be connected directly or indirectly to liquid source 53 so that liquid is recirculated between liquid source 53 and device 27.

[0309] Other features of the device and its operation may be the same as those described above in connection with FIG.

[0310] In this embodiment, valve 61 may be controlled to supply liquid to apparatus 27 to determine the amount or rate at which the liquid etches the coating. This information may be used to control or modify the dispensing of liquid from liquid dispenser 51 onto the surface of wafer W. For example, the apparatus may control the amount of liquid dispensed onto the surface of wafer W and / or the duration for which liquid is dispensed onto the surface of wafer W.

[0311] Alternatively, in this embodiment, valves 61 and 57 may be controlled to simultaneously supply liquid to the liquid dispenser so that the liquid is dispensed onto the wafer and into device 27, for example as described above.

[0312] In any of the above-described embodiments, a flow controller or limiter may be provided at or upstream of the input to the flow cell to control and / or limit the flow rate of liquid through the flow cell. For example, the flow rate may be limited to 10 mL / min or less, such as 5 mL / min or less. This may prevent or reduce leakage from the flow cell and / or damage to the flow cell, coating, or crystal.

[0313] The apparatus of the present invention may, for example, allow or enable the comparison or matching of different chemical supplies (eg, for different wafer processing equipment or for mixing systems on the same wafer processing equipment).

[0314] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, may be expressed in their specific form, or in terms of means for performing a disclosed function, or methods or processes for obtaining a disclosed result, as appropriate, and may be utilized separately or in any combination of such features to realize the invention in its various forms.

[0315] While the present invention has been described in conjunction with the exemplary embodiments set forth above, many equivalent modifications and variations will become apparent to those skilled in the art upon reading this disclosure. Accordingly, the exemplary embodiments of the invention set forth above are considered to be illustrative and not limiting. Various changes can be made to the described embodiments without departing from the spirit and scope of the invention.

[0316] For the avoidance of doubt, the theoretical explanations provided herein are provided for the purpose of enhancing the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.

[0317] The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0318] Throughout this specification, including the claims that follow, unless the context requires otherwise, the words "comprise" and "include," and variations such as "comprises," "comprising," and "including," are understood to imply the inclusion of stated integers or steps, or groups of integers or steps, but not the exclusion of other integers or steps, or groups of integers or steps.

[0319] It should be noted that as used in the specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, it is understood that the particular value forms another embodiment by use of the antecedent "about." The term "about" in reference to numerical values ​​is optional and means, for example, + / - 10%.

Claims

1. 1. An apparatus comprising: a quartz crystal microbalance comprising a quartz crystal resonator having a coating; a flow cell arranged to flow a liquid over the coating; An apparatus comprising:

2. 10. The apparatus of claim 1, The coating is SiO 2 , or Al 2 O 3 , or TiN, or Cu, or W, or Si, or Si 3 N 4 , or TaN, or Co, or SiO x , or W-doped C, or Co, or SnO x , or C, or SiC x N v 10. An apparatus comprising:

3. 3. The device according to claim 1 or claim 2, The coating comprises: 0.01 μm or more, and / or 0.1 μm or more, and / or 0.5 μm or more, and / or 1 μm or more, and / or 5 μm or less, and / or 10μm or less The device has a thickness of

4. The device according to any one of claims 1 to 3, The apparatus is configured to detect a resonant frequency of the crystal resonator.

5. The device according to any one of claims 1 to 4, The apparatus is configured to determine a shift in a resonant frequency of the crystal resonator.

6. 6. The apparatus of claim 5, The apparatus is configured to determine information indicative of an amount of etching of the coating by the liquid from the shift in the resonant frequency of the quartz crystal resonator.

7. 7. The apparatus of claim 5 or claim 6, The apparatus is configured to monitor etching of the coating by the liquid based on the shift in the resonant frequency of the quartz crystal resonator.

8. The device according to any one of claims 5 to 7, The apparatus, based on the shift in the resonant frequency of the crystal resonator, the etch rate of said coating, or a reduction in the mass per unit area of ​​said coating; or the reduction in the mass of the coating; or The reduction in the thickness of the coating The apparatus is configured to determine

9. An apparatus according to any one of claims 1 to 8, The apparatus comprises a liquid source connected to the flow cell and configured to supply liquid to the flow cell.

10. 10. The apparatus of claim 9, The apparatus, wherein the liquid is configured to etch the coating.

11. An apparatus according to any one of claims 1 to 10, The device comprises: a first liquid source connected to the flow cell for supplying a first liquid to the flow cell; a second liquid source connected to the flow cell for supplying a second liquid to the flow cell; one or more valves for controlling the supply of the first liquid to the flow cell and the supply of the second liquid to the flow cell; An apparatus comprising:

12. 12. The apparatus of claim 11, the first liquid is configured to etch the coating; and / or The second liquid comprises a cleaning liquid or a rinsing liquid. Device.

13. A wafer processing apparatus, a liquid dispenser for dispensing a liquid onto the surface of the wafer; a liquid supply for supplying liquid from a liquid source to the liquid dispenser; 13. The device according to claim 1, wherein the flow cell is a device connected to the liquid source or the liquid supply. A wafer processing apparatus comprising:

14. 14. The wafer processing apparatus according to claim 13, The flow cell is connected to the liquid source via a recirculation loop between the liquid source and the flow cell.

15. 14. The wafer processing apparatus according to claim 13, The wafer processing apparatus, wherein the flow cell is connected to the liquid supply in series with the liquid dispenser or in parallel with the liquid dispenser.

16. The wafer processing apparatus according to any one of claims 13 to 15, The wafer processing apparatus includes: dispensing the liquid from the liquid dispenser onto the surface of the wafer; Simultaneously supplying the liquid to the flow cell The wafer processing apparatus is configured as follows.

17. The wafer processing apparatus according to any one of claims 13 to 16, The wafer processing apparatus is configured to determine information indicative of an amount of etching of material on the surface of the wafer from the shift in the resonant frequency of the quartz resonator.

18. The wafer processing apparatus according to any one of claims 13 to 17, The wafer processing apparatus is configured to monitor etching of a material on the surface of the wafer based on a shift in the resonant frequency of the quartz crystal resonator.

19. The wafer processing apparatus according to any one of claims 13 to 18, The wafer processing apparatus performs the following calculation based on the shift in the resonant frequency of the crystal resonator: the etch rate of the material on the surface of the wafer; or a reduction in mass per unit area of ​​the material on the surface of the wafer; or a reduction in the mass of the material on the surface of the wafer; or a reduction in the thickness of the material on the surface of the wafer; The wafer processing apparatus is configured to determine

20. The wafer processing apparatus according to any one of claims 13 to 19, The wafer processing device is configured to control operation of the wafer processing device based on the shift in the resonant frequency of the crystal resonator.

21. 1. A method comprising: Using a flow cell to flow liquid over the coating on the quartz crystal resonator of a quartz crystal microbalance A method comprising:

22. 22. The method of claim 21, The method, wherein the liquid is configured to etch the coating.

23. 23. The method of claim 21 or claim 22, The coating is SiO 2 , or Al 2 O 3 , or TiN, or Cu, or W, or Si, or Si 3 N 4 , or TaN, or Co, or SiO x , or W-doped C, or Co, or SnO x , or C, or SiC x N v A method comprising one or more of:

24. The method according to any one of claims 21 to 23, The liquid is hydrofluoric acid or H 2 O 2 , or HNO 3 , or HNO 3 and HF, or DIO 3 , or NH 4 OH, or HCl.

25. The method according to any one of claims 21 to 24, The method includes detecting a resonant frequency of the crystal resonator.

26. The method according to any one of claims 21 to 25, The method includes determining a shift in a resonant frequency of the crystal resonator.

27. 27. The method of claim 26, The method includes determining information indicative of an amount of etching of the coating by the liquid from the shift in the resonant frequency of the quartz crystal resonator.

28. 28. The method of claim 26 or claim 27, The method includes monitoring etching of the coating by the liquid based on the shift in the resonant frequency of the quartz crystal resonator.

29. The method according to any one of claims 26 to 28, Based on the shift in the resonant frequency of the crystal resonator, the method comprises: the etch rate of said coating, or a reduction in the mass per unit area of ​​said coating; or a reduction in the mass of the coating; or A reduction in the thickness of the coating determining a

30. 30. The method according to any one of claims 21 to 29, The method includes simultaneously dispensing the liquid onto a surface of a wafer, the surface of the wafer comprising the same material as the coating.

31. 31. The method of claim 30, The method includes determining information indicative of an amount of etching of the material on the surface of the wafer from a shift in the resonant frequency of the quartz crystal resonator.

32. 32. The method of claim 30 or claim 31, The method includes monitoring etching of the material on the surface of the wafer from a shift in the resonant frequency of the quartz crystal resonator.

33. 33. The method according to any one of claims 30 to 32, The method further comprises, based on the shift in the resonant frequency of the crystal resonator: the etch rate of the material on the surface of the wafer; or a reduction in mass per unit area of ​​the material on the surface of the wafer; or a reduction in the mass of the material on the surface of the wafer; or a reduction in the thickness of the material on the surface of the wafer; determining a

34. 34. The method according to any one of claims 30 to 33, The method includes controlling dispensing of the liquid onto the surface of the wafer based on a shift in the resonant frequency of the quartz crystal resonator.

35. 35. The method according to any one of claims 21 to 34, The method comprises: flowing a cleaning or rinsing liquid over the coating on the quartz crystal resonator; subsequently flowing a liquid configured to etch the coating over the coating on the quartz resonator; then flowing a cleaning or rinsing liquid over the coating on the quartz resonator; A method comprising:

36. 36. The method of claim 35, The method comprises: detecting a first resonant frequency of the quartz crystal resonator while flowing the cleaning or rinsing liquid over the coating on the quartz crystal resonator prior to the liquid configured to etch the coating; detecting a second resonant frequency of the quartz crystal resonator while flowing the cleaning or rinsing liquid over the coating on the quartz crystal resonator after the liquid configured to etch the coating; determining a shift of the resonant frequency of the crystal resonator from the first resonant frequency and the second resonant frequency; A method comprising:

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