Apparatus and method for flow cell with quartz crystal microbalance

Abstract

An apparatus includes: a quartz crystal microbalance including a quartz crystal resonator having a coating; and a flow tank arranged to flow a liquid over the coating.

Description

Technical Field

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

[0002] In semiconductor device manufacturing, a number of different processes are typically performed on a semiconductor wafer to manufacture semiconductor devices on the semiconductor wafer. These processes typically include etching a layer of material that has been previously deposited on the surface of the semiconductor wafer to remove some of the material. This is typically accomplished by dispensing an etching chemical 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) may be dispensed onto the surface of the semiconductor wafer for a predetermined amount of time. However, the etching rate of the material may be significantly affected by the characteristics of the etching chemistry, and a small change in the characteristics of the etching chemistry (e.g., concentration and / or pH) may result in a significant change in the amount of etching occurring within the predetermined amount of time.

[0004] A single etching cycle performed on a material layer on a surface of a semiconductor wafer to etch the material may remove approximately Therefore, even when multiple etching cycles are performed, high sensitivity is required to monitor the etching.

[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 mass change 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 transferred to the external metrology tool, and thus may require a large amount of time, which may delay the manufacture of semiconductor devices. In addition, such techniques cannot monitor the etching amount in situ, but require the provision of additional external metrology tools.

[0006] It is also known to indirectly estimate the amount of etching of the material layer on the surface of the semiconductor wafer by measuring the concentration and / or pH value of the etching chemical that is (or will be) distributed to the surface of the semiconductor wafer. However, these techniques do not directly measure the amount of etching of the material layer by the etching chemical. In addition, these techniques may also require complex or expensive equipment to perform measurements, especially when processing etching chemicals composed of several different components, or in the case of bath loading (bathloading) / aging. Bath loading / aging refers to when the etching chemical is recycled and reused after being used to etch the material layer, the material accumulation of the etched material layer becomes a pollutant in the etching chemical. The presence of such pollutants in the etching chemical can, for example, reduce the etching rate of the etching chemical by reducing the concentration and / or pH value of the etching chemical.

[0007] Therefore, there is a need for improved techniques for monitoring etching of material layers, such as techniques that can be used in situ and / or do not require the provision of additional external metrology tools.

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

[0009] The quartz crystal microbalance can measure the mass change per unit area of ​​the quartz crystal resonator surface with high sensitivity, for example, about 1 ng / cm 2 Depending on the density of the material, this sensitivity can detect e.g. approx. Variation of material thickness.

[0010] The quartz crystal microbalance operates based on the piezoelectric effect, where the application of an electric field to a quartz crystal produces a mechanical deformation of the quartz crystal. By applying an oscillating electric field of an appropriate frequency to the quartz crystal, the quartz crystal can be made to oscillate at a specific resonant frequency. This resonant frequency can be a 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 of ​​the quartz crystal surface. Therefore, a change in the mass per unit area of ​​the quartz crystal surface will cause a shift in the resonant frequency of the quartz crystal. Therefore, by measuring the shift in the resonant frequency of the quartz crystal, the change in mass per unit area of ​​the quartz crystal surface can be calculated.

[0012] For example, the change in mass per unit area of ​​a quartz crystal surface can be calculated from the shift in the quartz crystal's resonant frequency using the following equation: Δm=-C·Δf where Δm is the change in mass per unit area of ​​the quartz crystal surface (e.g., in g / cm 2), Δf is the shift of the fundamental resonant frequency of the quartz crystal (in Hz), and C is a constant that depends on the characteristics of the quartz crystal used (for example, in g / (cm 2 The equation corresponds to the Sauerbrey equation known in the art and is therefore not described in detail here.

[0013] Figure 1 FIG. 1 is a simplified schematic diagram of a quartz crystal resonator 1 used in a quartz crystal microbalance. Figure 1 As shown, the quartz crystal resonator 1 includes a quartz crystal wafer 3. The quartz crystal wafer 3 can be cut from a bulk quartz crystal at an appropriate specific orientation relative to the crystallographic axis of the bulk quartz crystal. For example, the quartz crystal wafer 3 can be an AT-cut quartz crystal wafer. In addition, the quartz crystal resonator 1 includes a first electrode 5 disposed on a first major surface (e.g., top surface) of the quartz crystal wafer 3 and a second electrode 7 disposed on an opposite second major surface (e.g., bottom surface) of the quartz crystal wafer 3. The quartz crystal wafer 3 is thus sandwiched between the first electrode 5 and the second electrode 7.

[0014] The electrodes may, for example, comprise or consist of gold.

[0015] Typically, the first electrode 5 and / or the second electrode 7 are provided only on a portion of the first and / or second main surface of the quartz crystal wafer 3 , leaving a portion of the first and / or second main surface of the quartz crystal wafer 3 exposed.

[0016] Figure 1 In the embodiment, an alternating current and / or voltage source 9 is electrically connected to the quartz crystal resonator 1. Specifically, the alternating current and / or voltage source 9 is connected to the first electrode 5 and the second electrode 7 of the quartz crystal resonator 1, and is configured to apply an alternating current and / or voltage to the first electrode 5 and the second electrode 7. By applying an alternating current and / or voltage of a suitable frequency to the first electrode 5 and the second electrode 7, the quartz crystal wafer 3 can be made to oscillate at a resonant frequency (e.g., a fundamental resonant frequency) of the quartz crystal wafer 3. This resonant frequency of the quartz crystal wafer 3 can be detected in a conventional manner, and thus changes in the resonant frequency caused by changes in mass per unit area of ​​the surface of the quartz crystal wafer 3 can be detected. This is the general principle of operation of a quartz crystal microbalance.

[0017] Figure 2 FIG. 2 is a simplified schematic diagram of a quartz crystal microbalance 2. The quartz crystal microbalance 2 includes Figure 1 The quartz crystal resonator 1 includes a quartz crystal wafer 3 sandwiched between a first electrode 5 and a second electrode 7. Figure 1As shown and described above. In practice, the quartz crystal microbalance 2 generally includes a holder in which the quartz crystal resonator 1 is held and at least one main surface (eg, top surface) of the quartz crystal resonator 1 is exposed.

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

[0019] Of course, the quartz crystal microbalance 2 may also include Figure 2 Additional components beyond those shown.

[0020] Figure 3 The figure is a simplified schematic diagram of an oscillator circuit for detecting the resonant frequency of a quartz crystal resonator 1 that can be used in a quartz crystal microbalance 2. Figure 3 As shown, a quartz crystal resonator 1 is placed in an oscillator circuit, wherein the quartz crystal resonator 1 is driven to oscillate by an automatic gain control amplifier 8. The quartz crystal resonator 1 is terminated to a load resistor 10 connected to ground. By returning the voltage on the load resistor 10 to the input of the automatic gain control amplifier 8, the oscillator circuit will oscillate at a frequency with a loop phase shift of 0° or an integer multiple of 360° (provided that there is sufficient gain). This phase condition can be met when the quartz crystal resonator 1 resonates. Therefore, the resonant frequency of the quartz crystal resonator 1 can be determined by Figure 3 It is measured by the oscillation frequency of the oscillator circuit.

[0021] Of course, you can use Figure 3 The oscillator circuit shown uses a different type of circuit or detector to detect the resonant frequency of a quartz crystal resonator.

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

[0023] Quartz crystal microbalances have previously been used to monitor the deposition or adsorption of materials at quartz crystal surfaces, for example, monitoring vapor phase film deposition, or molecular adsorption at crystal interfaces in liquids, or self-assembled monolayer (SAM) coverage on crystal interfaces in liquids.

[0024] The present invention is designed in view of the above considerations. Summary of the invention

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

[0026] Generally speaking, the present invention relates to the use of a quartz crystal microbalance to monitor or study the etching of a coating formed on a quartz crystal resonator of the quartz crystal microbalance.

[0027] As mentioned above, a quartz crystal microbalance can be used to measure the mass change per unit area of ​​the quartz crystal resonator surface with high sensitivity, for example, about 1 ng / cm 2 Depending on the density of the coating material, this sensitivity can detect coating thicknesses of e.g. approx. changes.

[0028] Performing a single etch cycle on a material layer to etch the material may remove approximately 1 / 3 of the thickness of the material layer. or as low as a material layer thickness of about Therefore, a quartz crystal microbalance can provide sufficiently high sensitivity to monitor etching. In addition, a quartz crystal microbalance can be used to provide in-situ or online monitoring of etching.

[0029] According to a first aspect of the present invention, there is provided an apparatus comprising: a quartz crystal microbalance including 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 thereof where compatible.

[0031] The quartz crystal microbalance may have, for example, the features discussed above and / or Figures 1 to 3 Any features of the quartz crystal microbalance shown in .

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

[0033] A quartz crystal resonator may include a quartz crystal or a quartz crystal wafer.

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

[0035] The quartz crystal resonator (and / or quartz crystal or quartz crystal wafer) may be in the form of a disk or a wafer.

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

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

[0038] A quartz crystal resonator may include a quartz crystal or a quartz crystal wafer that is cut from a bulk quartz crystal at an appropriate specific orientation relative to the crystal axis 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] A quartz crystal or quartz crystal wafer may be sandwiched between a pair of electrodes.

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

[0041] A quartz crystal resonator may include a first electrode disposed on a first major face or surface of a quartz crystal or quartz crystal wafer and a second electrode disposed on an opposing second major face or surface of the quartz crystal or quartz crystal wafer.

[0042] The quartz crystal microbalance may include 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, comprise or consist of gold.

[0044] The first electrode may be provided only on a portion of the first principal face or main surface of the quartz crystal or quartz crystal wafer so that a portion of the first principal face or main surface of the quartz crystal or quartz crystal wafer is exposed.

[0045] The second electrode may be provided only on a portion of the second principal face or main surface of the quartz crystal or quartz crystal wafer so that a portion of the second principal face or main surface of the quartz crystal or quartz crystal wafer is exposed.

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

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

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

[0049] A quartz crystal resonator may have a fundamental resonant frequency of approximately 5 MHz.

[0050] A coating may refer to a layer of material disposed on a surface of a quartz crystal resonator, such as on a surface of a quartz crystal or a 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 face of a quartz crystal resonator (or quartz crystal or quartz crystal wafer).

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

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

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

[0056] A coating may be a layer of material deposited on the surface of a 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) that is partially covered by the first or second electrode and partially 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 layer 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 layer 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. Alternatively, the coating may comprise a plurality of different materials.

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

[0061] The mass per unit area of ​​the coating affects the resonant frequency of the 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 results in 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 reduction in the mass per unit area of ​​a quartz crystal resonator may result in an increase in the resonant frequency of the quartz crystal resonator.

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

[0064] A flow channel may refer to any flow path, or flow chamber, or channel, or tube arranged to flow a liquid over a coating.

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

[0066] A flow cell may include a flow path or flow chamber that contacts a liquid with a coating and flows the liquid over the coating.

[0067] Flowing a liquid over a coating may refer to causing the liquid to move or pass over the coating.

[0068] The flow cell can be configured so that the liquid contacts some, most, or all of the coating.

[0069] The flow cell may include an inlet for connecting the flow cell to a supply of liquid, such that liquid may enter the flow cell via the inlet.

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

[0071] The flow cell may be connected in a recirculation loop so that liquid is recirculated between a supply of liquid and the flow cell.

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

[0073] The volume of the flow path or flow chamber (e.g., from the inlet of the flow path or flow chamber to the outlet of the flow path or flow chamber) may be less than or equal to 10 mL. The volume may be greater than or equal to 0.1 mL. The volume may be greater than or equal to 0.1 mL and less than or equal to 10 mL. In specific embodiments, the volume may be greater than or equal to 1 mL and less than or equal to 2 mL, such as greater than or equal to 1.0 mL and less than or equal to 2.0 mL, such as about 1 mL.

[0074] The volume of the area in the flow path or flow chamber opposite (e.g., directly opposite) the area where the quartz crystal resonator contacts the liquid may be less than or equal to 2 mL, such as less than or equal to 2.0 mL. The volume may be greater than or equal to 0.05 mL. The volume may be greater than or equal to 0.05 mL and less than or equal to 2 mL or 2.0 mL, such as about 0.15 mL.

[0075] The volume of the area of ​​the flow path or flow chamber 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 opposing surface of the flow path or flow chamber may be less than or equal to 2 mL, for example, less than or equal to 2.0 mL. The volume may be greater than or equal to 0.05 mL. The volume may be greater than or equal to 0.05 mL and less than or equal to 2 mL or 2.0 mL, for example, about 0.15 mL.

[0076] The distance between the area in contact with the liquid in the quartz crystal resonator and the opposing surface of the flow path or flow chamber may be greater than or equal to 0.2 mm and less than or equal to 5 mm, for example, about 2 mm.

[0077] The contact area between the quartz crystal resonator and the liquid can be greater than or equal to 0.1cm 2 and less than or equal to 10cm 2 , for example about 0.5 cm 2 .

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

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

[0080] The quartz crystal resonator is arranged in or relative to the flow tank so that the coating on the quartz crystal resonator (or quartz crystal or quartz crystal wafer) is in contact with the liquid flowing in the flow tank.

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

[0082] The flow cell may have an opening or window in which the quartz crystal resonator is (at least partially) positioned or contained so that the coating on the quartz crystal resonator is in contact with the liquid flowing in the flow cell.

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

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

[0085] The flow channel can be configured to provide or achieve symmetrical liquid flow in the flow channel over the coating. This can 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 a constant temperature of the flow cell within ±0.5°C or within ±0.1°C.

[0087] The device 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 a constant temperature of the flow cell within ±0.5°C or within ±0.1°C.

[0088] The device 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 a constant temperature of the liquid in the flow cell within ±0.5°C or within ±0.1°C.

[0089] The device 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 a constant temperature of the liquid in the flow cell within ±0.5°C or within ±0.1°C.

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

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

[0093] The coating may include 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 SnO x , or C (such as polymer, or amorphous, or diamond-like), or SiC x N v Such materials are typically etched during the manufacture of semiconductor devices.

[0094] The coating may have a thickness greater than or equal to 0.5 μm. Assuming a typical etching cycle removes approximately This means that a 0.5 μm thick coating can be used to monitor approximately 50 etching cycles. If the etching cycle removes less material, e.g. If the coating is of a higher quality, the coating can be used to monitor more etching cycles, for example 500 etching cycles. The quartz crystal resonator can have a longer life.

[0095] The coating may have a thickness of: greater than or equal to 0.01 μm; and / or greater than or equal to 0.1 μm; and / or greater than or equal to 0.5 μm; and / or greater than or equal to 1 μm; and / or less than or equal to 5 μm; and / or less than or equal to 10 μm.

[0096] The coating may have a thickness greater than or equal to 0.01 μm and less than or equal to 5 μm or 10 μm.

[0097] A thickness as low as 0.01 μm can be used, for example, to detect whether etching has occurred.

[0098] The coating may have a thickness greater than or equal to 0.1 μm and less than or equal to 5 μm or 10 μm.

[0099] The coating may have a thickness greater than or equal to 1 μm and less than or equal to 5 μm or 10 μm.

[0100] The apparatus may be configured to detect a resonant frequency, such as a fundamental resonant frequency, of a quartz crystal resonator. The resonant frequency is the resonant frequency of oscillation of the quartz crystal resonator.

[0101] The quartz crystal microbalance may be configured to detect a resonant frequency, such as a fundamental resonant frequency, of a quartz crystal resonator.

[0102] The device or quartz crystal microbalance may include a detector configured to detect a resonant frequency, such as a 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 follows: Figure 3 As shown and described above.

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

[0105] The shift of the resonance frequency of a quartz crystal resonator means a change in the resonance frequency of the quartz crystal resonator.

[0106] The device or quartz crystal microbalance may be configured to determine information indicating 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 indicating the amount of etching of the coating by the liquid from the shift in the resonant frequency of the quartz crystal resonator.

[0107] As described 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, when the coating on the quartz crystal resonator is etched so that the mass per unit area of ​​the coating decreases, the resonant frequency of the quartz crystal resonator will shift.

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

[0111] The device or quartz crystal microbalance can 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 can be configured to determine that etching has not occurred when the resonant frequency of the quartz crystal resonator has not shifted.

[0112] The device may include 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 etching liquid 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 container.

[0118] The device may include: 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; 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 include a controller configured to control operation of one or more valves to supply 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 can be an etching solution or an etching chemical, such as hydrofluoric acid. Of course, other etching chemicals (such as H2O2) can also be used instead.

[0123] The etching solution 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 the second liquid.

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

[0128] The device (e.g., a controller or processor of the device) can be configured to control one or more valves to first supply a first liquid (e.g., a cleaning or rinsing liquid) to the flow tank for a predetermined period of time, and then subsequently supply a second liquid (e.g., an etching liquid or etching chemical) to the flow tank for a predetermined period of time, and then subsequently supply the first liquid to the flow tank for a predetermined period of time.

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

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

[0131] The holder may hold a quartz crystal resonator, wherein a coating of the quartz crystal resonator is exposed and / or accessible.

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

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

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

[0135] According to a second aspect of the present invention, a wafer processing device is provided, which includes: a liquid dispenser for dispensing liquid onto a wafer surface; a liquid supply portion for supplying liquid from a liquid source to the liquid dispenser; and a device according to the first aspect of the present invention, wherein a flow tank is connected to the liquid source or the liquid supply portion.

[0136] Therefore, the same liquid that is dispensed onto the wafer surface can also be supplied to the flow cell of the apparatus according to the first aspect of the invention. Therefore, if the material of the coating is the same as the material of the wafer surface, and the liquid is an etching liquid configured to etch the material, the amount of etching or etching rate of the coating can be the same as, or related to, or corresponding to, the amount of etching or etching rate of the wafer surface material.

[0137] Thus, by monitoring the etching of the coating, the etching of material on the wafer surface can be indirectly monitored and / or predicted.

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

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

[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 etching liquid or etching chemistry 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 or located or disposed on an arm of the wafer handling apparatus.

[0144] The arm may be pivotably mounted to enable the position of the nozzle relative to the wafer to be changed.

[0145] Wafer handling apparatus 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, and liquid is dispensed onto the wafer from above, ie, onto the top surface of the wafer.

[0148] The liquid source may be a container or tank containing a certain volume of liquid. Alternatively, the liquid source may be a flow path, pipe or channel that supplies liquid to a liquid supply of a wafer processing device.

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

[0150] The liquid supply may include one or more flow paths, tubes or channels for supplying liquid to the liquid dispenser.

[0151] There may be a plurality of different liquid sources for supplying different liquids (eg, cleaning or rinsing liquid and etching liquid) to the liquid dispenser.

[0152] A single liquid supply may be connected to each of the plurality of different liquid sources for supplying a different liquid to the liquid dispenser. Alternatively, there may be a plurality of liquid supplies for supplying liquid from a liquid source to the liquid dispenser.

[0153] There may be more than one liquid distributor. For example, a different liquid distributor may be used for each different liquid supplied from each liquid source.

[0154] Where there is more than one liquid supply and / or liquid source, the flow cell may be connected to each of the liquid sources and / or liquid supplies.

[0155] The connection of the flow channel to a liquid source or liquid supply means that liquid can be supplied to the flow channel so that the liquid flows through the coating. Therefore, the connection is a fluid connection or a liquid connection.

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

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

[0158] For example, the liquid source can be a tank or container of liquid, and the flow cell can 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 distributor or in parallel with the liquid distributor.

[0160] Liquid exiting the flow cell may be recovered and / or reused and / or recirculated, for example by returning to a liquid source and / or liquid supply. For example, the apparatus may include a recovery line connecting the output of the flow cell to the liquid source and / or liquid supply. Alternatively, liquid exiting the flow cell may be collected or disposed of.

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

[0162] Thus, when liquid is dispensed onto the wafer surface, the liquid is also supplied to the flow channel and flows through the coating. Thus, the amount of etching of the coating may be the same as, or related to, or corresponding to the amount of etching of the wafer surface material.

[0163] For example, the wafer processing apparatus may include one or more valves for controlling the dispensing of liquid onto the wafer surface and for supplying liquid to the flow tank. The wafer processing apparatus may also include a controller or processor for controlling the operation of one or more valves to control the dispensing of liquid onto the wafer surface and for supplying liquid to the flow tank.

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

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

[0166] The wafer handling device can be configured to control and / or modify subsequent dispensing of liquid onto the wafer surface based on the information indicating the amount of coating etched. For example, the wafer handling device can control the amount of liquid dispensed onto the wafer surface or the duration of liquid dispensed onto the wafer surface based on the information indicating the amount of coating etched.

[0167] For example, the wafer handling device can be configured to determine the etching rate of the coating by the liquid. The wafer handling device can then control and / or modify the subsequent dispensing of the liquid onto the wafer surface based on the determined etching rate. For example, the wafer handling device can control the amount of liquid dispensed onto the wafer surface, or the duration of the liquid dispensed onto the wafer surface.

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

[0169] The wafer surface may have a coating or layer of the same material as the coating of the quartz crystal resonator.

[0170] The liquid may be an etching solution or etching chemical configured to etch the material.

[0171] The term etching liquid or etching chemical may refer to a liquid or chemical configured to etch a coating.

[0172] The wafer processing apparatus (eg, a controller of the apparatus) may be configured to determine, calculate, or estimate information indicative of an amount of etched wafer surface material from a shift in the resonant frequency of the quartz crystal resonator.

[0173] The wafer processing apparatus (eg, a controller of the apparatus) may be configured to monitor etching of wafer surface material based on or shifting from a resonant frequency of a quartz crystal resonator.

[0174] A wafer processing device (e.g., a controller of the device) may be configured to determine, calculate, or estimate, based on a shift in the resonant frequency of a quartz crystal resonator: an etch rate of wafer surface material; or a reduction in mass per unit area of ​​wafer surface material; or a reduction in mass of wafer surface material; or a reduction in thickness of wafer surface material.

[0175] The wafer processing apparatus (eg, a controller or processor of the wafer processing apparatus) may be configured to control the operation of the liquid dispenser based on a shift in the resonant frequency of the quartz crystal resonator.

[0176] The wafer processing apparatus (eg, a controller or processor of the wafer processing apparatus) may be configured to control operation of the wafer processing apparatus based on a shift in the resonant frequency of the quartz crystal resonator.

[0177] For example, when a desired or predetermined amount of etching of a coating is determined, the wafer processing apparatus may be configured to stop the liquid dispenser from dispensing liquid.

[0178] The wafer processing device (e.g., a controller or processor of the wafer processing device) can be configured to determine whether the resonant frequency of the quartz crystal resonator has undergone an expected or predetermined shift, and stop dispensing liquid onto the wafer surface when it is determined that the resonant frequency of the quartz crystal resonator has undergone an expected or predetermined shift.

[0179] According to a third aspect of the present invention, there is provided a method comprising: flowing a liquid over a coating on a quartz crystal resonator of a quartz crystal microbalance using a flow cell.

[0180] The method according to the third aspect of the present invention may have any features of the first aspect and / or the second aspect of the present invention unless incompatible.

[0181] The method according to the third aspect of the present invention may be performed using the apparatus according to the first aspect of the present invention or the wafer processing apparatus according to the second aspect of the present invention.

[0182] The third aspect of the present invention may have any one of the following optional features, or any combination thereof where compatible.

[0183] The liquid may be configured to etch the coating.

[0184] The method may include detecting or determining whether the coating is etched by the liquid.

[0185] The method may include monitoring or studying etching of the coating by the liquid.

[0186] The coating may include 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 SnO x , or C, or SiC x N v One or more of .

[0187] The liquid may contain hydrofluoric acid. Of course, other etching chemicals may be used instead, such as H2O2.

[0188] The liquid may include one or more of hydrofluoric acid, or H2O2, or HNO3, or HNO3 and HF, or DIO3, or NH4OH, or HCL.

[0189] The liquid may be deionized.

[0190] The method may include detecting a resonant frequency of the quartz crystal resonator, such as a fundamental resonant frequency.

[0191] The method may include determining a shift or change in the resonant frequency of the quartz crystal 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 will reduce the mass per unit area of ​​the coating and thus cause a shift in the resonant frequency of the quartz crystal resonator. Therefore, by determining a shift or change in the resonant frequency of the quartz crystal resonator, etching of the coating may be monitored.

[0192] 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.

[0193] The method may include monitoring etching of the coating by the liquid based on or shifting from a resonant frequency of the quartz crystal resonator.

[0194] The method may include determining or calculating, based on a shift in the resonant frequency of the quartz crystal resonator: an etch rate of the coating; or a reduction in mass per unit area of ​​the coating; or a reduction in mass of the coating; or a reduction in thickness of the coating.

[0195] The method may be, for example, a method of monitoring or controlling wafer etching, or wafer processing, or semiconductor device manufacturing.

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

[0197] The method may include controlling and / or modifying the dispensing of liquid onto the wafer surface based on a calculated coating etch rate, or a reduction in mass per unit area of ​​the coating, or a reduction in mass of the coating, or a reduction in thickness of the coating. For example, the method may include controlling the amount of liquid dispensed onto the wafer surface, or the duration of liquid dispensed onto the wafer surface.

[0198] The method may include simultaneously dispensing a liquid onto a surface of the wafer, wherein the surface of the wafer includes the same material as the coating. For example, the wafer may include a layer or coating of the material on the surface of the wafer.

[0199] The method may include determining, calculating, or estimating information indicative of an amount of etched wafer surface material 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.

[0200] The method may include determining, calculating, or estimating, based on a shift in the resonant frequency of the quartz crystal resonator: an etch rate of wafer surface material; or a reduction in mass per unit area of ​​wafer surface material; or a reduction in mass of wafer surface material; or a reduction in thickness of wafer surface material.

[0201] The method may include controlling the dispensing of liquid onto the wafer surface based on 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. For example, the method may include determining whether a desired or predetermined shift in the resonant frequency of the quartz crystal resonator has occurred, and stopping the dispensing of liquid onto the wafer surface when it is determined that the desired or predetermined shift in the resonant frequency of the quartz crystal resonator has occurred.

[0202] The method may include flowing a cleaning or rinsing liquid over a coating on a quartz crystal resonator; then flowing a liquid configured to etch the coating over the coating on the quartz crystal resonator; and then flowing the cleaning or rinsing liquid over the coating on the quartz crystal resonator.

[0203] The method may include: detecting a first resonant frequency of the quartz crystal resonator when a cleaning or rinsing liquid flows over a coating on the quartz crystal resonator before the liquid configured to etch the coating; detecting a second resonant frequency of the quartz crystal resonator when a cleaning or rinsing liquid flows over the coating on the quartz crystal resonator after the liquid configured to etch the coating; and determining a shift in a 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.

[0204] The method may include performing a first etching step of flowing an etching solution through the coating to etch the coating, determining whether the 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 of flowing an etching solution through the coating to etch the coating.

[0205] The method may include monitoring etching of the coating by the liquid and then controlling or modifying the dispensing of the same liquid onto the wafer surface based on the monitoring results.

[0206] For example, the method may include determining an etch rate or amount of a coating layer by a liquid, and then controlling or modifying the dispensing of the same liquid onto the wafer surface based on the determined etch rate or amount of the coating layer.

[0207] The present invention includes the combination of described aspects and preferred features unless such combination is expressly impermissible or explicitly avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0208] Embodiments and experiments illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings, in which:

[0209] Figure 1 A simplified schematic diagram of a quartz crystal resonator used in a quartz crystal microbalance.

[0210] Figure 2 A simplified schematic diagram of a quartz crystal microbalance.

[0211] Figure 3 A simplified schematic diagram of an oscillator circuit for detecting the resonant frequency of a quartz crystal resonator that can be used in a quartz crystal microbalance.

[0212] Figure 4 is a schematic diagram of an apparatus according to an embodiment of the present invention.

[0213] Figure 5 is a schematic diagram of an apparatus according to an embodiment of the present invention.

[0214] Figure 6 is a schematic diagram of an apparatus according to an embodiment of the present invention.

[0215] Figure 7is a schematic diagram of measurement results according to an embodiment of the present invention.

[0216] Figure 8 is a schematic diagram of an apparatus according to an embodiment of the present invention.

[0217] Fig. 9 is a schematic diagram of an apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION

[0218] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated herein by reference.

[0219] Embodiments of the present invention may include Figures 1 to 3 Any features, such as those described above.

[0220] Figure 4 Schematic diagram of a device according to an embodiment of the present invention. Figure 4 As shown, the device 11 includes a flow channel 13. The flow channel 13 includes a tube 15 or a flow chamber along which a liquid can flow as shown by arrows 17. In addition, the flow channel 13 includes an opening 19 or a window in a side surface of the tube 15 (e.g., a peripheral surface).

[0221] The device 11 also includes a quartz crystal microbalance 2. The quartz crystal microbalance 2 may have, for example, the above-mentioned and / or Figures 1 to 3 The quartz crystal microbalance 2 shown in the figure has any features. Specifically, the quartz crystal microbalance 2 includes a quartz crystal resonator 1, which may have, for example, the above-mentioned and / or Figures 1 to 3 The quartz crystal resonator 1 shown in the drawings may be any of the features of the quartz crystal resonator 1. Specifically, the quartz crystal resonator 1 includes a quartz crystal wafer 3, which can be cut from a bulk quartz crystal at an appropriate specific orientation relative to the crystal axis of the bulk quartz crystal. For example, the quartz crystal wafer 3 can be an AT-cut quartz crystal wafer. The quartz crystal wafer 3 is sandwiched between a pair of electrodes 5 and 7, such as Figure 1 Specifically, the first electrode 5 is disposed on the first (eg, top) surface of the quartz crystal wafer 3, and the second electrode 7 is disposed on the second (eg, bottom) surface of the quartz crystal wafer 3. For simplicity, Figure 4 The electrodes 5 and 7 are not shown.

[0222] The electrodes 5 and 7 may, for example, comprise or consist of gold.

[0223] Quartz crystal wafer 3 may be, for example, disk-shaped.

[0224] The quartz crystal wafer may have a thickness between 100 μm and 500 μm, for example 330 μm.

[0225] Although not shown for brevity Figure 4 In the embodiment, the quartz crystal microbalance 2 further includes a controller 4 and a crystal oscillator electronic device 6, such as Figure 2 As shown. The crystal oscillator electronics 6 is electrically connected to the quartz crystal resonator 1 and configured to drive the oscillation of the quartz crystal resonator 1, for example, by applying an alternating current and / or voltage to the first electrode 5 and the second electrode 7 of the quartz 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 the oscillation of the quartz crystal resonator 1 and detect the resonant frequency of the quartz crystal resonator 1, for example, the fundamental resonant frequency of the quartz crystal resonator 1.

[0226] The quartz crystal microbalance 2 may also include Figure 3 The oscillator circuit shown and described above is used to detect the resonant frequency of the quartz crystal resonator 1. Of course, other types of oscillator circuits can also be used to detect the resonant frequency of the quartz crystal resonator 1 instead.

[0227] like Figure 4 As shown, a coating 23 is provided on the surface (main surface) of the quartz crystal wafer 3. As described below, a variety of different materials can be used for the coating, 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 SnO x , or C, or SiC x N v The coating 23 is a material layer on the surface of the quartz crystal wafer 3 .

[0228] The coating layer 23 may have a thickness greater than or equal to 0.5 μm, for example. The coating layer may have a thickness less than or equal to 3 μm, for example.

[0229] The coating layer 23 may cover all or part of the main surface of the quartz crystal wafer 3. In the present embodiment, the coating layer 23 is formed only on the main surface of the quartz crystal wafer 3.

[0230] In the present embodiment, first electrode 5 is formed on the top surface of quartz crystal wafer 3 so as to cover only a portion of the top surface of quartz crystal wafer 3, and coating 23 is formed on another portion of the top surface of quartz crystal wafer 3 so as to cover another portion of the top surface of quartz crystal wafer 3. In other words, first electrode 5 and coating 23 are provided on different portions of the top surface of quartz crystal wafer 3. This is not shown in FIG. Figure 4 For simplicity. Figure 4As shown, the quartz crystal resonator 1 is held and / or supported by a holder 25. In particular, the holder 25 holds the quartz crystal resonator 1 so that the coating 23 provided on the surface of the quartz crystal wafer 3 is exposed. Specifically, the coating 23 is on the first main surface of the quartz crystal wafer 3, and the holder 25 holds the quartz crystal resonator 1 from the second main surface of the quartz crystal wafer 3.

[0231] In particular, coating 23 is formed on the top surface of quartz crystal wafer 3 , and the bottom surface of quartz crystal wafer 3 is positioned in holder 25 such that coating 23 is exposed and / or accessible.

[0232] The retainer 25 is disposed in the opening 19 in the side surface of the tube 15 so that the coating 23 is exposed to the liquid flowing along the tube 15. Therefore, when the liquid flows along the tube 15, the liquid contacts the coating 23 and flows through the coating 23.

[0233] In particular, the holder 25 and thus the quartz crystal resonator 1 held by the holder 25 are placed in the opening 19 in the side surface of the tube 15 , with the coating 23 arranged to face the inside of the tube 15 .

[0234] Thus, when a liquid configured to etch the material of coating 23 flows along tube 15 , the liquid contacts coating 23 and flows through coating 23 , causing coating 23 to be etched by the liquid.

[0235] When the liquid configured to etch the coating 23 flows in the tube 15, Figure 4 The device 11 shown can be used to study or monitor the etching of the coating 23. The liquid can be, for example, hydrofluoric acid, or another etching liquid or chemical, such as H2O2.

[0236] In particular, the quartz crystal microbalance 2 can be used to measure the mass reduction per unit area of ​​the coating 23 on the surface of the quartz crystal wafer 3 caused by etching, by measuring the change in the mass change per unit area of ​​the coating 23 caused by etching and the change in the oscillation frequency of the quartz crystal resonator 1 (or the quartz crystal wafer 3). Specifically, as described above, the resonant frequency of the quartz crystal resonator 1 depends on the mass per unit area of ​​the surface of the quartz crystal resonator 1. Therefore, the mass change per unit area of ​​the surface of the quartz crystal resonator 1 will cause 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 mass change per unit area of ​​the surface of the quartz crystal resonator 1 can be determined (e.g., calculated).

[0237] In particular, a reduction in the mass per unit area of ​​the coating 23 may result in an increase in the resonance frequency of the quartz crystal resonator 1 .

[0238] The quartz crystal microbalance 2 may have a value of about 1 ng / cm2 The sensitivity of the coating to changes in mass per unit area is usually less than or equal to For example, to achieve SiO2 Thickness change, 27ng / cm 2 To achieve the mass reduction per unit area of ​​Al2O3 Thickness change, 40ng / cm 2 To achieve the mass reduction per unit area of ​​TiN Thickness change, 54ng / cm 2 The mass per unit area is reduced.

[0239] The thickness of the coating 23 may be less than or equal to 3 μm. Such a thickness of the coating 23 does not significantly affect the sensitivity of the quartz crystal microbalance 2 .

[0240] Assuming a typical etch cycle removes approximately This means that a 3 μm thick coating 23 can be used to monitor about 300 etching cycles.

[0241] The device may include one or more heaters or coolers for controlling the temperature of the quartz crystal wafer 3 and / or the flow tank 13 and / or the liquid in the flow tank 13. In addition, the device may include one or more temperature sensors for sensing the temperature of the quartz crystal wafer 3 and / or the flow tank 13 and / or the liquid in the flow tank 13. The device may also 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 a constant temperature or a substantially constant temperature of the quartz crystal wafer 3 and / or the flow tank 13 and / or the liquid in the flow tank 13.

[0242] The resonant frequency of a quartz crystal resonator can be detected using a flow cell or an outlet of a flow cell at a predetermined or fixed height to prevent pressure changes caused by height changes from affecting the detection of the resonant frequency.

[0243] Quartz crystal wafer 3 may be configured to have a fundamental resonance frequency of, for example, about 5 MHz or on the order of 5 MHz.

[0244] Quartz crystal wafer 3 may have a diameter of, for example, about 25 mm, or on the order of 25 mm, or 25 mm. Alternatively, quartz crystal wafer may have a diameter of, for example, about 14 mm, or on the order of 14 mm, or 14 mm.

[0245] Figure 5 Schematic diagram of a device according to a second embodiment of the present invention. Figure 5As shown, the device 27 includes a flow tank 29 having a Figure 4 Different configurations of flow cell 13 are shown.

[0246] like Figure 5 As shown, the flow tank 29 includes an inlet 31 for connecting the flow tank 29 to a liquid supply, so that liquid can enter the flow tank 29 via the inlet 31. The flow tank 29 also includes an outlet 33 for connecting the flow tank 29 to an external flow path 35 (e.g., a tube), so that liquid can leave the flow tank 29 via the outlet 33. The outlet can be directly or indirectly connected to the liquid supply, so that the liquid leaving the flow tank 29 is recycled and reused.

[0247] In addition, the flow tank 29 includes a flow chamber 37 or a flow path connected to the inlet 31 and the outlet 33 so that the liquid can flow from the inlet 31 to the outlet 33 through the flow chamber 37. The flow chamber 37 is arranged 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 flow the liquid over the coating 23.

[0248] In particular, if Figure 5 As shown, the quartz crystal resonator 1 of the quartz crystal microbalance is placed or accommodated in a flow tank 29. For example, the flow tank 29 may include a space or cavity in which the quartz crystal 3 can be placed. The flow tank 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.

[0249] The quartz crystal resonator 1, the coating 23 and the quartz crystal microbalance in this embodiment may have the above or Figures 1 to 4 The quartz crystal resonator 1, coating 23 and quartz crystal microbalance 2 of the first embodiment shown in any one of the embodiments are compatible unless they are incompatible. Although not shown, the quartz crystal resonator 1 includes electrodes 5 and 7 on the quartz crystal wafer 3, such as Figure 1 In addition, the quartz crystal microbalance includes a controller 4 and a crystal oscillator electronic device 6, such as Figure 2 The quartz crystal microbalance may also include Figure 3 The oscillator circuit shown and described above is used to detect the resonant frequency of the quartz crystal resonator 1. Of course, other types of oscillator circuits may also be used to detect the resonant frequency of the quartz crystal resonator 1. Therefore, the description of these features will not be repeated here for the sake of brevity.

[0250] The flow chamber 37 of the flow cell is arranged so that the flow chamber 37 or a portion of the flow chamber 37 is adjacent to the coating 23 , so that the liquid flowing through the flow chamber 37 contacts the coating 23 and flows through the coating 23 .

[0251] The flow chamber 37 or a portion of the flow chamber 37 has an open side facing the coating 23 so that the liquid flowing through the flow chamber can contact the coating 23 .

[0252] Flow chamber 37 or a portion of flow chamber 37 may be disk-shaped so that the liquid contacts coating 23 in a circular area or region of the top surface of coating 23 .

[0253] The flow tank 29 is made of or includes a material that is not etched by the etching liquid. For example, the flow tank can be made of or include polytetrafluoroethylene (PTFE). In general, the flow tank is made of or includes a chemically inert material. In particular, the flow tank 29 includes a material that is inert and / or compatible with the liquid (e.g., etching liquid or etching chemical) supplied to the flow tank.

[0254] The volume of the flow chamber 37 (e.g., from the inlet of the flow chamber 37 to the outlet of the flow chamber 37) can be less than or equal to 10 mL. The volume can be greater than or equal to 0.1 mL. The volume can be greater than or equal to 0.1 mL and less than or equal to 10 mL. In a specific embodiment, the volume can be greater than or equal to 1 mL and less than or equal to 2 mL, such as greater than or equal to 1.0 mL and less than or equal to 2.0 mL, such as about 1 mL.

[0255] The volume of the area of ​​the flow chamber 37 opposite (e.g., directly opposite) the area where the quartz crystal resonator contacts the liquid may be less than or equal to 2 mL, for example, less than or equal to 2.0 mL. The volume may be greater than or equal to 0.05 mL. The volume may be greater than or equal to 0.05 mL and less than or equal to 2 mL or 2.0 mL, for example, about 0.15 mL.

[0256] The volume of the area of ​​the 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 opposing surface of the flow chamber 37 may be less than or equal to 2 mL, for example, less than or equal to 2.0 mL. The volume may be greater than or equal to 0.05 mL. The volume may be greater than or equal to 0.05 mL and less than or equal to 2 mL or 2.0 mL, for example, about 0.15 mL.

[0257] The distance between the area in contact with the liquid in the quartz crystal resonator and the opposing surface of the flow chamber may be greater than or equal to 0.2 mm and less than or equal to 5 mm, for example, about 2 mm.

[0258] The area of ​​the quartz crystal resonator in contact with the liquid can be greater than or equal to 0.1 cm 2 and less than or equal to 10cm 2 , for example about 0.5 cm 2 .

[0259] Figure 6 The connection to the liquid supply is shown Figure 5 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 connected to the inlet 31 of the flow tank 29 through corresponding flow paths. A first valve 43 is provided in the flow path connecting the first liquid container 39 to the inlet 31, and a second valve 45 is provided in the flow path connecting the second liquid container 41 to the inlet 31.

[0260] The first valve 43 may be opened to supply the first liquid to the inlet 31 of the flow cell 29, or closed to prevent the first liquid from being supplied to the inlet 31. Similarly, the second valve 45 may be opened to supply the second liquid to the inlet 31 of the flow cell 29, or closed to prevent the second liquid from being supplied to the inlet 31.

[0261] In this embodiment, the first liquid is a cleaning or rinsing liquid, such as deionized water. In addition, the second liquid is an etching liquid or chemical substance, such as hydrofluoric acid. Of course, other etching chemicals, such as H2O2, can also be used instead.

[0262] In device operation, the first valve 43 may be set to open and the second valve 45 may be set to closed so that a cleaning or flushing liquid is supplied to the flow cell 29. Thus, the cleaning or flushing liquid flows through the flow chamber 37 across the coating 23 and cleans or flushes the coating 23. This may be referred to as a first cleaning or flushing step.

[0263] Subsequently, the first valve 43 may be set to close and the second valve 45 may be set to open so that the etching liquid is supplied to the flow tank 29. Thus, the etching liquid flows through the flow chamber 37 across the coating 23 and etches the coating, thereby changing the mass per unit area of ​​the coating 23 and thus changing the resonant frequency of the quartz crystal resonator 1. This may be referred to as an etching step.

[0264] Subsequently, the first valve 43 may be set to open and the second valve 45 may be set to closed so that a cleaning or flushing liquid is supplied to the flow cell 29. Thus, the cleaning or flushing liquid flows through the flow chamber 37 across the coating 23 and cleans or flushes the coating 23. This may be referred to as a second cleaning or flushing step.

[0265] The apparatus may include a controller 47 configured to control the opening and closing of the first valve 43 and the second valve 45 to control the supply of the first and second liquids to the flow tank 29 .

[0266] Figure 7 is an example of measurement data obtained during operation of the above-mentioned device.

[0267] Figure 7Regions A and C in FIG. 5 correspond to the first cleaning or rinsing step and the second cleaning or rinsing step, respectively. Figure 7 Region B in FIG. 4 corresponds to the etching step.

[0268] like Figure 7 As shown, during the first cleaning or rinsing step, only the cleaning or rinsing liquid is supplied to the flow tank 29, and the resonant frequency of the quartz crystal resonator 1 is determined to be 5 MHz. This resonant frequency is determined by the characteristics of the quartz crystal wafer 3 and the characteristics of the coating 23 (i.e., the mass per unit area of ​​the coating 23).

[0269] like Figure 7 As shown, during a subsequent etching step, when the cleaning or rinsing liquid in flow tank 29 is replaced with an etching liquid, the resonant frequency initially decreases due to the difference in density and viscosity between the cleaning or rinsing liquid and the etching liquid.

[0270] When the etching liquid is supplied to the flow tank 29, the etching liquid etches the coating 23, removing some of the coating 23 and thereby reducing the mass per unit area of ​​the coating 23. The gradual reduction in the mass per unit area of ​​the coating 23 causes the resonant frequency of the quartz crystal resonator 1 to gradually increase, as shown in FIG. Figure 7 shown.

[0271] like Figure 7 As shown, during the subsequent second cleaning or rinsing step, when the etching liquid in the flow tank 29 is replaced with the cleaning or rinsing liquid, the resonant frequency initially increases due to the difference in density and viscosity between the cleaning or rinsing liquid and the etching liquid. Figure 5 As shown, the resonant frequency is stabilized at a stable value.

[0272] like Figure 5 As shown, 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 has been etched between the first cleaning or rinsing step and the second cleaning or rinsing step, so that the mass per unit area of ​​the coating 23 in the second cleaning or rinsing step is less than the mass per unit area of ​​the coating 23 in the first cleaning or rinsing step.

[0273] By measuring the shift or change in the resonant frequency between the first cleaning or rinsing step and the second cleaning or rinsing step, the mass change per unit area of ​​the coating 23 caused by etching can be determined or calculated. Therefore, the amount of etching of the coating 23 by the etching liquid can be determined, and the etching can be monitored. For example, the etching rate of the coating 23 by the liquid can be calculated.

[0274] Alternatively, instead of comparing the resonance frequency of quartz crystal wafer 3 between the first cleaning or rinsing step and the second cleaning or rinsing step, the resonance frequency of quartz crystal wafer 3 at the beginning of the etching step in which the etching liquid is supplied to flow tank 29 and the resonance frequency of quartz crystal wafer 3 at the end of the etching step in which the etching liquid is supplied to flow tank 29 may be compared. Figure 7 The resonant frequency near the beginning of region B is Figure 7 The shift in the resonant frequency of the quartz crystal element is determined between the resonant frequencies near the end of region B.

[0275] In practice, the resonant frequency measured after changing from a cleaning or rinsing solution to an etching solution and vice versa may need to be higher than Figure 7 The stabilization time may be several minutes, for example.

[0276] Alternatively, the first resonant frequency of the quartz crystal resonator 1 may be measured while the quartz crystal resonator 1 is dry. For example, the initial resonant frequency of the quartz crystal resonator 1 may be measured in a dry state, i.e., when no liquid is applied to the coating 23. Then, an etching liquid may be applied to the coating 23 on the quartz crystal wafer 3 to etch the coating 23. Subsequently, the quartz crystal resonator 1 may be dried, and the second resonant frequency of the quartz crystal resonator 1 may be measured while the quartz crystal resonator 1 is dry. In addition, a cleaning or rinsing liquid may be applied to the coating 23 after and / or before the etching liquid is applied to the coating 23.

[0277] The quartz crystal resonator 1 and / or the coating 23 may be dried by supplying a gas such as N2 to the quartz crystal resonator 1 and / or the coating 23 to dry the coating. For example, the gas may be supplied by Figure 6 One of the liquid supply paths shown or by an additional gas supply path connected to a gas container or tank is provided. The device may include a valve for controlling the supply of gas to the quartz crystal resonator 1 and / or the coating 23.

[0278] Of course, in other embodiments of the present invention, flow cells of different configurations may be used to replace the flow cell 13 of the first embodiment and the flow cell 29 of the second embodiment.

[0279] The apparatus of the present invention may be used or applied to monitor etching of material on a wafer surface during wafer processing, such as during semiconductor device manufacturing.

[0280] Figure 8 is a schematic diagram of an apparatus according to an embodiment of the present invention.

[0281] like Figure 8As shown, the wafer processing apparatus 49 according to the present embodiment includes a liquid dispenser 51 for dispensing liquid onto the surface of the wafer W. The wafer processing apparatus 49 is used to etch the material on the surface of the wafer W by dispensing the 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.

[0282] like Figure 8 As shown, the wafer processing apparatus 49 includes a liquid source 53 and a liquid supply portion 55 for supplying liquid from the liquid source 53 to the liquid dispenser 51 .

[0283] For example, the liquid source 53 may be a container or tank of liquid. Alternatively, the liquid source 53 may be a flow path, a pipe or a channel that supplies liquid to the liquid supply portion 55 of the wafer processing device 49.

[0284] The liquid supply 55 includes a flow path, such as a tube or a channel, configured to supply liquid from the liquid source 53 to the liquid dispenser 51 .

[0285] The liquid source 53 may be external to the wafer processing apparatus 49 and therefore not a part of the wafer processing apparatus 49. Alternatively, the wafer processing apparatus 49 may include the liquid source 53.

[0286] The liquid supply portion 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 portion 55. In particular, the valve 57 can be opened so that the liquid is supplied from the liquid source 53 to the liquid dispenser 51, or closed so that the liquid is not supplied from the liquid source 53 to the liquid dispenser 51.

[0287] The operation of valve 57 may be controlled by controller 47 of wafer handling apparatus 49 .

[0288] Controller 47 may control device 49 to perform an etching cycle in which valve 57 is opened for a predetermined period of time so that etching liquid is supplied from liquid source 53 to liquid dispenser 51 and dispensed onto the surface of wafer W for a predetermined period of time. The etching liquid is configured to etch material on the wafer surface.

[0289] In addition, the wafer processing apparatus 49 also includes the apparatus 27 of the second embodiment described above. Of course, the apparatus 11 of the first embodiment described above may be used instead of the apparatus 27 of the second embodiment, or a flow tank having a different configuration from that used in the first or second embodiment may be used.

[0290] like Figure 8 As shown, the device 27 of the second embodiment is connected to the liquid supply 55. In particular, the flow path branches from the liquid supply 55 and is connected to the device 27. In particular, the inlet 31 of the flow tank 29 is connected to the liquid supply 55. Figure 8In the embodiment, when valve 57 is open, liquid is supplied to device 27 and liquid dispenser 51 simultaneously. However, in other embodiments, one or more additional valves, and / or a movable valve 57, may be provided so that the liquid supply to device 27 can be controlled independently of the liquid supply to liquid dispenser 51.

[0291] exist Figure 8 In the embodiment, when the etching liquid is supplied from the liquid source 53 to the liquid dispenser 51 and dispensed onto the wafer, the etching liquid is simultaneously supplied from the liquid supply portion 55 to the flow chamber 37 of the flow trough 29, in which the etching liquid flows through the coating 23 of the quartz crystal wafer 3 and etches the coating 23.

[0292] Of course, the device 27 may alternatively be connected directly to the liquid source 53 , and further valves may be provided to control the supply of liquid from the liquid source 53 to the device 27 .

[0293] The material of the coating layer 23 is selected to be the same as the material of the surface of the wafer W to be etched. Therefore, when the liquid is supplied to the wafer W and the coating layer 23 simultaneously, the coating layer 23 is etched simultaneously with the etching of the material on the surface of the wafer W.

[0294] In particular, since the material of the coating layer 23 is the same as the material of the surface of the wafer W, when both are exposed to the liquid in the same or corresponding manner, the amount of etching of the coating layer 23 by the liquid may be the same as, related to, or corresponding to the amount of etching of the material on the surface of the wafer W. Therefore, by monitoring the etching of the coating layer 23 as described above, the etching of the material on the surface of the wafer W may be indirectly monitored.

[0295] Wafer processing device 49 (eg, controller 47 ) may be configured to determine, calculate, or estimate information indicative of an amount of material etched from the surface of wafer W from the shift in the resonant frequency of the quartz crystal resonator of device 27 .

[0296] Wafer processing device 49 (eg, controller 47 ) may be configured to monitor etching of wafer W surface material based on or from a shift in the resonant frequency of a quartz crystal resonator of device 27 .

[0297] The wafer processing device 49 (e.g., controller 47) can be configured to determine, calculate or estimate, based on the shift in the resonant frequency of the quartz crystal resonator of the device 27: the etching rate of the wafer surface material; or the mass reduction per unit area of ​​the wafer surface material; or the mass reduction of the wafer surface material; or the thickness reduction of the wafer surface material.

[0298] The wafer processing apparatus (eg, controller 47) may be configured to control the operation of the liquid dispenser 51 or the wafer processing apparatus based on the shift in the resonant frequency of the quartz crystal resonator.

[0299] For example, when a desired or predetermined amount of etching of the coating 23 is determined, the wafer processing device 49 (eg, the controller 47) may be configured to stop the liquid dispenser 51 from dispensing the liquid.

[0300] Wafer handling apparatus 49 (eg, controller 47) may be configured to determine whether a desired or predetermined shift has occurred in the resonant frequency of the quartz crystal resonator and to stop dispensing liquid onto the wafer surface when it is determined that the resonant frequency of the quartz crystal resonator has shifted in the desired or predetermined manner.

[0301] The liquid dispenser 51 comprises a nozzle for dispensing liquid onto the surface of the wafer. The nozzle is positioned or located or arranged on an arm of the wafer handling device 49. The arm is pivotally mounted so that the position of the nozzle relative to the wafer W can be changed.

[0302] The wafer handling apparatus includes a support or chuck 59 for supporting or holding the wafer. The support or chuck 59 may be rotatable.

[0303] like Figure 8 As shown, a support or chuck 59 supports wafer W from below, and liquid is dispensed onto the wafer from above, ie, onto the top surface of the wafer.

[0304] although Figure 8 Only a single liquid source 53 is shown, but multiple liquid sources 53 may be provided. Figure 6 , the device 49 may include a first liquid source 53 and a second liquid source 53 having respective valves for supplying the first liquid and the second liquid to the liquid supply 55. Alternatively, a separate liquid supply may be provided for each liquid source to supply the respective liquid to the liquid dispenser 51 and the device 27.

[0305] The first liquid may be a cleaning or rinsing liquid, and the second liquid may be an etching liquid, similar to the reference Figure 6 The arrangement described.

[0306] The device 49 may be controlled (e.g., by the controller 47) to first simultaneously supply the cleaning or rinsing liquid to both the liquid dispenser 51 and the device 27. Subsequently, the device 49 may be controlled to supply the etching liquid to both the liquid dispenser 51 and the device 27 at a second time. Subsequently, the device 49 may be controlled to supply the cleaning or rinsing liquid to both the liquid dispenser 51 and the device 27 at a third time. The above description of the device 27 in each step is equally applicable to this embodiment.

[0307] A single liquid supply 55 may be connected to each of a plurality of different liquid sources for supplying a different liquid to the liquid dispenser 51. Alternatively, there may be a plurality of liquid supplies for supplying liquid to the liquid dispenser 51 from a liquid source.

[0308] There may be more than one liquid dispenser 51. For example, a different liquid dispenser 51 may be used for each different liquid supplied from each liquid source.

[0309] In some embodiments, the device can be controlled to supply liquid to the device 27 without supplying liquid to the liquid dispenser 51. Based on the shift in the resonant frequency of the quartz crystal resonator, the device can determine the etching rate or amount of the coating by the liquid. The device can then use this information to control or modify the subsequent distribution of liquid from the liquid dispenser 51 onto the surface of the wafer W. For example, the device can control the amount of liquid distributed onto the surface of the wafer W and / or the duration of dispensing the liquid onto the surface of the wafer W based on the determined etching rate or etching amount.

[0310] Fig. 9 Shows Figure 8 A modified version of the device of , in which the device 27 is directly connected to the liquid source 53 via a flow path. A valve 61 is provided in the flow path for controlling the supply of liquid to the device from the liquid source 53. Although not shown, the outlet of the device may be directly or indirectly connected to the liquid source 53 so that the liquid is recirculated between the liquid source 53 and the device 27.

[0311] Other features of the device and its operation may be similar to those described above with respect to Figure 8 Same as described.

[0312] In this embodiment, valve 61 can be controlled to supply liquid to device 27 to determine the amount or rate of etching of the coating by the liquid. This information can then be used to control or modify the distribution of liquid from liquid dispenser 51 onto the surface of wafer W. For example, the device can control the amount of liquid distributed onto the surface of wafer W, and / or the duration of dispensing liquid onto the surface of wafer W.

[0313] Alternatively, in this embodiment, valves 61 and 57 may be controlled to simultaneously supply liquid to the liquid dispenser to dispense the liquid onto the wafer and to device 27, for example as described above.

[0314] In any of the above embodiments, a flow controller or restrictor may be disposed at or upstream of the input of the flow cell to control and / or limit the flow rate of the liquid through the flow cell. For example, the flow rate may be limited to less than or equal to 10 mL / minute, such as less than or equal to 5 mL / minute. This may prevent or reduce leakage of the flow cell and / or damage to the flow cell, coating, or quartz crystal.

[0315] The apparatus of the present invention may allow or enable, for example, the comparison or matching of different chemical supply sources (eg, for use in different wafer processing apparatuses or a mixing system on the same wafer processing apparatus).

[0316] The features disclosed in the above description, or in the following claims, or in the accompanying drawings, expressed in their specific form or as means for performing the disclosed functions, or as methods or processes for obtaining the disclosed results, may be used to implement the invention in various forms, separately or in any combination of such features, where appropriate.

[0317] Although the present invention has been described in conjunction with the above exemplary embodiments, when the present disclosure is given, many equivalent modifications and variations are apparent to those skilled in the art. Accordingly, the above exemplary embodiments of the present invention are considered to be illustrative rather than restrictive. Various changes may be made to the embodiments without departing from the spirit and scope of the present invention.

[0318] For the avoidance of any doubt, any theoretical explanations provided herein are provided to enhance the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.

[0319] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0320] Throughout this specification, including the appended claims, unless the context requires otherwise, the words "comprises" and "comprising" and variations such as "including" and "comprising", will be understood to imply the inclusion of a specified integer or step or groups of integers or steps but not the exclusion of any other integer or step or groups of integers or steps.

[0321] It must 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 a value is expressed as an approximation by using the antecedent "about", it will be understood that the particular value forms another embodiment. The term "about" in relation to a value is optional and means, for example, + / - 10%.

Claims

1. A device comprising: A quartz crystal microbalance comprising a quartz crystal resonator having a coating; as well as A flow channel is arranged to flow liquid over the coating.

2. The device according to claim 1, wherein the coating comprises 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 SnO x , or C, or SiC x N v One or more of .

3. The device according to claim 1 or claim 2, wherein the coating has a thickness of: Greater than or equal to 0.01 μm; and / or Greater than or equal to 0.1 μm; and / or Greater than or equal to 0.5 μm; and / or Greater than or equal to 1 μm; and / or Less than or equal to 5 μm; and / or Less than or equal to 10μm.

4. An apparatus according to any preceding claim, wherein the apparatus is configured to detect the resonant frequency of the quartz crystal resonator.

5. An apparatus according to any preceding claim, wherein the apparatus is configured to determine a shift in the resonant frequency of the quartz crystal resonator.

6. The apparatus of claim 5, wherein 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. An apparatus according to claim 5 or claim 6, wherein 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 apparatus according to any one of claims 5 to 7, wherein the apparatus is configured to determine, based on the shift in the resonant frequency of the quartz crystal resonator: the etch rate of the coating; or a reduction in the mass per unit area of ​​the coating; or The mass of the coating is reduced; or The thickness of the coating is reduced.

9. An apparatus according to any of the preceding claims, wherein the apparatus comprises a liquid source connected to the flow cell and configured to supply liquid to the flow cell.

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

11. The device according to any one of the preceding claims, wherein the device comprises: 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; as well as 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.

12. The device according to claim 11, wherein: The first liquid is configured to etch the coating, and / or The second liquid comprises a cleaning or flushing fluid.

13. A wafer processing device comprising: a liquid dispenser for dispensing liquid onto the surface of the wafer; a liquid supply portion for supplying liquid from a liquid source to the liquid dispenser; as well as The device according to any one of claims 1 to 12, wherein the flow channel is connected to the liquid source or the liquid supply.

14. The wafer processing apparatus of claim 13, wherein the flow cell is connected to the liquid source via a recirculation loop between the liquid source and the flow cell. 15 . The wafer processing apparatus according to claim 13 , wherein the flow tank is connected to the liquid supply part which is connected in series with the liquid distributor or in parallel with the liquid distributor.

16. The wafer processing apparatus according to any one of claims 13 to 15, wherein the wafer processing apparatus is configured to: dispensing the liquid from the liquid dispenser onto the surface of the wafer; and The liquid is simultaneously supplied to the flow cell.

17. The wafer processing apparatus according to any one of claims 13 to 16, wherein the wafer processing apparatus is configured to determine information indicating an etching amount of material of the surface of the wafer from a shift of the resonance frequency of the quartz crystal resonator.

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

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

20. The wafer processing apparatus according to any one of claims 13 to 19, wherein the wafer processing apparatus is configured to control an operation of the wafer processing apparatus based on a shift of the resonance frequency of the quartz crystal resonator.

21. A method comprising: A flow cell is used to flow liquid over a coating on a quartz crystal resonator of a quartz crystal microbalance.

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

23. The method according to claim 21 or claim 22, wherein the coating comprises 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 SnO x , or C, or SiC x N v One or more of .

24. The method of any one of claims 21 to 23, wherein the liquid comprises one or more of hydrofluoric acid, or H2O2, or HNO3, or HNO3 and HF, or DIO3, or NH4OH, or HCL.

25. A method according to any one of claims 21 to 24, wherein the method comprises detecting the resonant frequency of the quartz crystal resonator.

26. A method according to any one of claims 21 to 25, wherein the method comprises determining a shift in the resonant frequency of the quartz crystal resonator.

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

28. A method according to claim 26 or claim 27, wherein the method comprises monitoring etching of the coating by the liquid based on the shift in the resonant frequency of the quartz crystal resonator.

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

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

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

32. A method according to claim 30 or claim 31 , wherein the method comprises monitoring etching of the material of the surface of the wafer from a shift in the resonant frequency of the quartz crystal resonator.

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

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

35. A method according to any one of claims 21 to 34, wherein the method comprises: flowing a cleaning or rinsing fluid over the coating on the quartz crystal resonator; then flowing a liquid configured to etch the coating over the coating on the quartz crystal resonator; as well as A cleaning or rinsing fluid is then flowed over the coating on the quartz crystal resonator.

36. The method of claim 35, wherein the method comprises: detecting a first resonant frequency of the quartz crystal resonator while flowing the cleaning or rinsing fluid 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 subsequent to the liquid configured to etch the coating; as well as From the first resonant frequency and the second resonant frequency, a shift in the resonant frequency of the quartz crystal resonator is determined.

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