Device for measuring weight or mass of object

Abstract

A device for measuring the weight or mass of an object, comprising: a support for supporting the object during the weight or mass measurement; and a dynamometer; wherein the support is electrically isolated from at least a portion of the dynamometer; and wherein the support is electrically connected to the ground.

Description

Technical Field

[0001] The present invention relates to a device for measuring the weight or mass of an object, such as a device for measuring the weight or mass of a semiconductor wafer. Background Art

[0002] Microelectronic devices are fabricated on semiconductor (e.g., silicon) wafers using a variety of techniques, such as deposition techniques and removal techniques. The semiconductor wafers can be further processed in ways that change their mass, such as by cleaning, ion implantation, lithography, etc.

[0003] Wafer processing techniques typically cause changes in mass at or on the surface of the semiconductor wafer. The configuration of these surface changes is often critical to the function of the device, so it is necessary to evaluate the wafers during production for quality control purposes to determine if they have the correct configuration.

[0004] Specialized metrology tools can be used in the production flow such that monitoring is performed soon after the relevant process of interest and typically before any subsequent processing (i.e., between processing steps).

[0005] Measuring the change in mass of a wafer on either side of a processing step is a sought-after method for implementing product wafer metrology. This method is relatively low-cost, fast, and can automatically adapt to different wafer circuit patterns. In addition, this method can typically provide results with higher accuracy compared to alternative techniques. The relevant wafer is weighed before and after the processing step of interest. Then, the change in mass is correlated with the performance of the production apparatus and / or the desired characteristics of the wafer.

[0006] On a wafer, charges can exist on its surface (surface charge) or within its body (substrate) (embedded charge). Charges can be caused by a variety of means, such as early processing or manufacturing steps, tribology, contact electrification, etc.

[0007] When a charged wafer is on the weighing pan of a weighing device and the charges on the wafer are not released, the charges can cause an electrostatic force between the wafer and the surrounding environment. For example, there may be an electrostatic force between the wafer and the load cell of the weighing device or between the wafer and the measurement housing of the weighing device.

[0008] This electrostatic force can cause the gravity measured by the load cell to be erroneously high or low, depending on the direction of the electrostatic force, resulting in an error in the weight measurement and thus an error in the calculated wafer mass based on the weight measurement.

[0009] Therefore, a more advantageous approach is to allow the charged wafers present on the weighing pan of the weighing device to discharge at least partially before the measurement is performed. One way to achieve this is to allow the charge on the wafer to discharge at least partially to the ground (or earth) through the weighing pan and the force sensor.

[0010] Specifically, the force sensor of the weighing device is typically made of at least one or more conductive materials (such as one or more metals) and is typically electrically connected to the ground (or earth). The weighing pan of the weighing device can also be made of at least a part of one or more conductive materials (such as one or more metals), so that when the wafer is placed on the weighing pan, any charge on the wafer can be released to the ground (or earth) through the weighing pan and the force sensor. Specifically, there is usually an electrical path or conductive path from the weighing pan to the ground via the force sensor.

[0011] In this document, the ground or earth can refer to the reference point for measuring voltage or the physical connection to the earth.

[0012] However, the inventors have understood that with this arrangement, the resistance of the force sensor means that the charge of the wafer on the weighing pan may not be effectively discharged to the ground (or earth) through the force sensor. Therefore, when the weight measurement is performed, the wafer may still have at least some charge, resulting in an error in the weight measurement and thus an error in the calculated wafer mass based on the weight measurement.

[0013] The present invention has been designed in view of the above considerations. Summary of the Invention

[0014] The inventors have realized that the above problem can be solved by providing a relatively low-resistance path from the weighing pan to the ground (or earth) that bypasses the force sensor, so that the charge on the wafer can be effectively discharged to the ground (or earth) before the measurement is performed.

[0015] Therefore, in the most general case, the present invention relates to providing a device for measuring the weight or mass of an object, wherein the support of the device is electrically isolated from at least a part of the force sensor of the device, and wherein the support is electrically connected to the ground (or earth).

[0016] According to a first aspect of the present invention, there is provided a device for measuring the weight or mass of an object, comprising: a support for supporting the object during the weight or mass measurement; and a force sensor; wherein the support is electrically isolated from at least a part of the force sensor; and wherein the support is electrically connected to the ground (or earth).

[0017] According to a first aspect of the present invention, the support is electrically isolated from at least a portion of the force sensor, such that charge cannot be released from the support through the force sensor. However, the support is electrically connected to ground separately, such that charge can be released from the support to ground through the electrical connection.

[0018] Thus, the charge of an object on the support can be effectively released to ground through the electrical connection between the support and ground. This can effectively reduce or remove the charge on the object, thereby preventing or reducing one or more of the problems associated with the charge on the object during measurement as discussed above.

[0019] The device according to the first aspect of the present invention may have any one of the following optional features, or any combination of the following optional features in a compatible case.

[0020] The device can be used to measure the weight or mass of a wafer (e.g., a semiconductor wafer).

[0021] The device can be used to measure the weight or mass of a wafer having a predetermined diameter (e.g., 300 mm).

[0022] The device can be configured or adjusted to measure the weight or mass of an object.

[0023] The device can be used to measure the mass of an object. For example, the device can be a semiconductor wafer mass metering device.

[0024] The support can be configured or adjusted to support an object during weight or mass measurement.

[0025] The support can be a weighing pan or include a weighing pan. Thus, unless incompatible, the term "support" can be replaced throughout with the term "weighing pan". The weighing pan can be a weighing scale pan or a balance scale pan.

[0026] The support can be a weighing support.

[0027] The support can include a support portion for supporting an object and a mounting portion for mounting the support on the force sensor. For example, the mounting portion can include a shaft, such as a longitudinal shaft.

[0028] The support can include a weighing pan portion and a shaft connected to the weighing pan portion. This shaft can be a longitudinal shaft.

[0029] The support can be mounted on the force sensor, or coupled to the force sensor, or connected to the force sensor.

[0030] Supporting an object can mean supporting the weight of the object.

[0031] Supporting an object can mean supporting or carrying the object.

[0032] A dynamometer can be used to measure the weight or mass of an object supported by a support member.

[0033] The dynamometer can be configured or adjusted to measure the weight or mass of an object supported by a support member.

[0034] The dynamometer can be used to weigh an object.

[0035] The dynamometer can be used to perform a weight measurement on an object.

[0036] The dynamometer can be used to produce a measurement output indicating the mass or weight of an object.

[0037] The support member can be used to support an object during a weight or mass measurement performed by the dynamometer.

[0038] The dynamometer can be grounded (electrically connected to the ground or earth).

[0039] The dynamometer can include a gravity converter or be a gravity converter.

[0040] The dynamometer can include a gravity sensor or be a gravity sensor.

[0041] The dynamometer can produce a measurement output based on a measurement of the amount of electromagnetic force compensation required to compensate (or balance) the weight loaded on the support member.

[0042] The dynamometer can be configured to balance the gravitational force of an object loaded on a support member with the force exerted when an electromagnetic coil of the dynamometer is energized in a magnetic field of the dynamometer. Specifically, the dynamometer can be configured to supply a current to the electromagnetic coil sufficient to balance the force exerted on the electromagnetic coil with the gravitational force of the object. The measurement output of the dynamometer can be produced based on the required current. Thus, the dynamometer can include an electromagnetic coil disposed in a magnetic field and a controller for controlling the current supplied to the electromagnetic coil.

[0043] The dynamometer can include a permanent magnet that generates a magnetic field.

[0044] The permanent magnet can be positioned below or beneath the electromagnetic coil. Of course, the permanent magnet can be positioned differently relative to the electromagnetic coil, such as above the electromagnetic coil, and / or to the side of the electromagnetic coil, and / or inside the electromagnetic coil, and / or around the electromagnetic coil.

[0045] When an appropriate current is supplied to the electromagnetic coil, the electromagnetic coil and the permanent magnet are configured to be subject to a magnetic attraction force therebetween.

[0046] The dynamometer can include or be an electromagnetic force compensation or electromagnetic force restoring force sensor or dynamometer.

[0047] The force measuring device can include or be an electromagnetic force compensation or electromagnetic force restoring force sensor, or a force measuring device including an electromagnetic coil.

[0048] The support can be connected, coupled, or attached to the force measuring device or mounted on the force measuring device.

[0049] The support can be electrically isolated from at least a portion of the force measuring device such that charge on the support or on an object on the support cannot discharge through the force measuring device, for example, cannot discharge to ground through the force measuring device.

[0050] The support can be electrically isolated from at least a portion of the force measuring device such that there is no electrical path or conductive path from the support through the force measuring device, for example, from the support through the force measuring device to ground.

[0051] The electrical isolation of the support from at least a portion of the force measuring device can mean that there is no electrical path or conductive path between the support and at least a portion of the force measuring device, or that there is an electrical path or conductive path between the support and at least a portion of the force measuring device, and the resistance of the electrical path or conductive path is, for example, 1 M ohm or greater.

[0052] The force measuring device can be electrically connected to ground (or earth), and the support can be electrically isolated from at least a portion of the force measuring device such that charge on the support or on an object on the support cannot discharge to ground through the force measuring device.

[0053] The force measuring device can be electrically connected to ground (or earth), and the support can be electrically isolated from at least a portion of the force measuring device such that there is no electrical path or conductive path from the support through the force measuring device to ground.

[0054] The support can be electrically isolated from the force measuring device.

[0055] The support can be electrically isolated from the entire force measuring device, or all of the force measuring device, or substantially the entire force measuring device, or substantially all of the force measuring device.

[0056] The support can be electrically isolated from most parts, a majority, or the main part of the force measuring device.

[0057] The support can be electrically isolated from a portion of the force measuring device.

[0058] The electrical isolation of the support from at least a portion of the force measuring device means that electric power or charge cannot conduct from the support to at least a portion of the force measuring device, or that substantially no electric power or charge can conduct from the support to at least a portion of the force measuring device.

[0059] For example, the electrical isolation of the force measuring device from at least a portion of the force measuring device can mean that there is no electrical path or conductive path between the support and at least a portion of the force measuring device.

[0060] The support being electrically connected to the ground means that electric power or charge can be conducted from the support to the ground directly or indirectly via one or more other components (e.g., via the mounting portion discussed below).

[0061] For example, the support being electrically connected to the ground means that there is an electrical path or conductive path directly or indirectly via one or more other components (e.g., via the mounting portion discussed below) between the support and the ground.

[0062] The electrical connection can be a direct electrical connection or an indirect electrical connection via one or more other components.

[0063] The ground (or earth) can refer to a reference point for measuring voltage or a physical connection to the earth.

[0064] The electrical connection between the support and the ground does not pass through at least a portion of the force sensor. For example, the electrical connection between the support and the ground can not pass through the force sensor or the main part of the force sensor.

[0065] The electrical connection between the support and the ground can bypass the force sensor, or bypass at least a portion of the force sensor, or bypass the main part of the force sensor.

[0066] The electrical connection between the support and the ground can be a low-resistance electrical connection, e.g., an electrical connection having a lower resistance than the electrical connection through the force sensor would have. For example, the resistance can be less than or equal to 100 ohms, or less than or equal to 10 ohms, or less than or equal to 5 ohms, or less than or equal to 2 ohms, or less than or equal to 1 ohm.

[0067] The force sensor can be an electromagnetic force compensation force sensor.

[0068] The force sensor can be configured to convert or transform the gravity loaded on the support into a current that is proportional to the gravity, or based on the gravity, or determined according to the gravity.

[0069] The device can include an electrical insulator or electrical insulating material that electrically isolates the support from at least a portion of the force sensor.

[0070] For example, the device can include a sheet or plate or layer of electrical insulator or electrical insulating material disposed between the support and at least a portion of the force sensor.

[0071] The electrical insulator or electrical insulating material can include a non-conductive ceramic, such as alumina.

[0072] Alternatively or additionally, the electrical insulator or electrical insulating material can include a non-conductive glass or non-conductive glass ceramic, such as Macor.

[0073] Alternatively or additionally, the electrical insulator or electrical insulating material may comprise a non-conductive polymer, such as Kapton or Delrin or polyetheretherketone (PEEK) or polyamide or polypropylene.

[0074] Alternatively or additionally, the electrical insulator or electrical insulating material may comprise a non-conductive composite material.

[0075] Alternatively or additionally, the electrical insulator or electrical insulating material may comprise a non-conductive glass composite material, such as glass fiber.

[0076] The support member comprises a conductive material, such as metal. The support member may be made of or mainly made of a conductive material (such as metal).

[0077] The load cell may comprise a conductive material, such as metal. The load cell may be made of or mainly made of a conductive material (such as metal).

[0078] At least the housing or casing of the load cell may comprise or be made of a conductive material, such as metal.

[0079] The device may comprise an electrical path or conductive path between the support member and the ground. The electrical path or conductive path may comprise one or more conductors. For example, one or more conductors may comprise one or more of conductive metal wires and conductive foils.

[0080] The device may comprise a mounting portion for mounting the support member on the load cell; and the support member and the mounting portion may be electrically isolated from at least a part of the load cell.

[0081] At least a part of the load cell may refer to the whole of the load cell except the mounting portion.

[0082] The mounting portion may be regarded as part of the load cell. In this case, the mounting portion and the support member may be electrically isolated from the remaining part of the load cell attached or connected to the mounting portion.

[0083] The mounting portion and the support member may be electrically isolated from at least a part of the load cell attached or connected to the mounting portion.

[0084] Alternatively, the mounting portion may be regarded as separate from the load cell. In this case, the mounting portion and the support member may be electrically isolated from the load cell, such as from the whole load cell or all of the load cell.

[0085] The mounting portion may comprise a receiving portion, and a part of the support member is received within the receiving portion. For example, the shaft of the support member may be received in the receiving portion.

[0086] The mounting portion may comprise a raised boss or groove or opening for receiving the shaft of the support member. The boss may be a cylindrical boss.

[0087] The mounting part may include a board or sheet or part having a receiving part.

[0088] An electrical insulator or electrical insulating material may be positioned below the mounting part.

[0089] For example, an electrical insulator or electrical insulating material may be positioned directly below the mounting part, such as in direct contact with the lower side or bottom of the mounting part.

[0090] An electrical insulator or electrical insulating material may be positioned below the receiving part.

[0091] The electrical path or conductive path between the support and the ground may include a conductor attached or connected or fixed to the mounting part, for example implemented using a connector attached or connected or fixed to the mounting part.

[0092] The conductor may include a conductive metal wire or conductive foil, for example made of a metal such as gold. The conductive metal wire may be made of copper, for example.

[0093] When an object is loaded onto the support, a part of the electrical path or conductive path between the support and the ground that is deformed or bent may include a conductive foil, such as gold foil. The conductive foil may have a lower resistance to deformation or bending than the metal wire, so that the influence of the movement of the support on the electrical path or conductive path and thus on the measurement output of the force sensor can be minimized.

[0094] A part of the electrical path or conductive path between the support and the ground may extend between the moving part and the fixed part of the device; and a part of the electrical path or conductive path may include a conductive foil, such as a conductive foil made of a metal such as gold.

[0095] A part of the electrical path or conductive path between the support and the ground may extend between the moving part and the fixed part of the force sensor; and a part of the electrical path or conductive path may include a conductive foil, such as a conductive foil made of a metal such as gold.

[0096] The electrical path or conductive path may have a low resistance, for example a resistance less than or equal to 100 ohms, or less than or equal to 10 ohms, or less than or equal to 5 ohms, or less than or equal to 2 ohms, or less than or equal to 1 ohm.

[0097] The device may include a measurement chamber electrically connected to the ground, and the support may be electrically connected to the measurement chamber.

[0098] The device may further include one or more sensors configured to sense one or more atmospheric conditions (such as the atmospheric conditions inside the measurement chamber). For example, one or more sensors may be configured to sense one or more of temperature, pressure, or humidity in the measurement chamber.

[0099] The device may further comprise a controller configured to calculate the weight or mass of an object based on the output of the force sensor.

[0100] The device may further comprise a controller configured to calculate the weight or mass of an object based on the output of the force sensor and the output of one or more sensors.

[0101] For example, the controller may be configured to calculate the buoyancy force acting on the object based on the output of one or more sensors and to correct the weight or mass measurement of the object based on the calculated buoyancy force.

[0102] The controller may be configured to correct the weight or mass measurement affected by the buoyancy force acting on the object based on the output of one or more sensors.

[0103] According to a second aspect of the present invention, there is provided a device for measuring the weight or mass of an object, comprising: a support for supporting the object during weight or mass measurement; and a force sensor; wherein the support is electrically connected to ground through an electrical path or conductive path that does not pass through the force sensor, or bypasses the force sensor, or does not go through the force sensor.

[0104] The second aspect of the present invention may have any of the features of the first aspect of the present invention described above, unless incompatible.

[0105] The present invention includes combinations of the described aspects and preferred features, unless such combinations are clearly not permitted or are explicitly avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] Embodiments illustrating the principles of the present invention will now be discussed with reference to the accompanying drawings, in which:

[0107] Figure 1 Schematic diagram of a first device for measuring the weight or mass of an object.

[0108] Figure 2 Schematic diagram of a second device for measuring the weight or mass of an object.

[0109] Figure 3 Schematic diagram of a device for measuring the weight or mass of an object according to an embodiment of the present invention.

[0110] Figure 4 Schematic diagram of a device for measuring the weight or mass of an object according to another embodiment of the present invention.

[0111] Figure 5A and Figure 5B Schematic diagram of a mounting portion for mounting a weighing pan of a device for measuring the weight or mass of an object. Figure 5A Schematic cross-sectional view of the mounting portion, Figure 5BSchematic top view of the mounting part.

[0112] Figure 6 Is Figure 5A Schematic diagram of the mounting part of, where the weighing pan is mounted on the mounting part.

[0113] Figure 7 Schematic diagram of a device for measuring the weight or mass of an object according to an embodiment of the present invention. Detailed implementation manners

[0114] Aspects and embodiments of the present invention will now be discussed with reference to the accompanying drawings. Other aspects and embodiments will be apparent to those skilled in the art. All documents mentioned herein are incorporated herein by reference.

[0115] Figure 1 Is a schematic diagram of a device 1 for measuring the weight or mass of an object. For example, the device 1 may comprise an electronic balance or a force gauge. As Figure 1 Shown, the device 1 comprises a weighing pan 3 located on a shaft 5. The shaft 5 is connected to a fixed (i.e., rigid and stationary) body 7 via a balance beam 9. The balance beam 9 is rigidly / firmly attached or connected to the shaft 5 at one end thereof, and attached or connected to the fixed body 7 at a flexure point at the other end of the balance beam 9. The flexure point is a point at which the balance beam 9 can flex and / or bend, for example in response to a load applied to the weighing pan 3. For example, the flexure point may be a narrowing in the balance beam 9. The fixed body 7 may comprise, for example, a base and / or the housing of the device 1.

[0116] When a load is applied to the weighing pan 3, for example by placing an object on the weighing pan 3, the shaft 5 can be displaced downward in the vertical direction by flexing or bending of the balance beam 9 at the flexure point.

[0117] An electromagnetic coil 11 is positioned below the shaft 5, or around the lower part of the shaft 5. However, the electromagnetic coil 11 can be positioned elsewhere. The electromagnetic coil 11 is located within the magnetic field of a magnet 13. The magnet 13 can be a permanent magnet or an electromagnet.

[0118] Of course, Figure 1 Only the magnet 13 is schematically shown in, and the shape and / or configuration and / or position of the magnet 13 can be different from Figure 1 Shown.

[0119] In addition, Figure 1 Only the electromagnetic coil 11 is schematically shown in, and the shape and / or configuration and / or position of the electromagnetic coil 11 can be different from Figure 1 Shown.

[0120] When using device 1, an object whose weight or mass is to be measured (such as a semiconductor wafer) is placed on the weighing pan 3. In the absence of any balancing force, due to the moment generated by the weight of the object, the balance beam 9 will flex or bend at the flexure point, and the weighing pan 3 and the shaft 5 will move downward.

[0121] When current is supplied to the electromagnetic coil 11, the electromagnetic coil 11 generates a magnetic field. The interaction between the magnetic field generated by the electromagnetic coil 11 and the magnetic field generated by the magnet 13 causes the electromagnetic coil 11 to be subjected to a force, the magnitude and direction of which are determined by the magnitude and direction of the current applied to the electromagnetic coil 11.

[0122] By applying a current of appropriate magnitude and direction to the electromagnetic coil 11, an upward force equal in magnitude and opposite in direction to the weight of the object on the weighing pan 3 can be applied to the electromagnetic coil 11. In this case, the electromagnetic coil 11 will remain stationary and will not move downward because the two forces acting on the balance beam 9 will cancel each other out, meaning there is no resultant force on the balance beam 9. For example, this force can be the repulsive magnetic force between the electromagnetic coil 11 and the magnet 13, which acts upward on the electromagnetic coil 11. The magnet 13 can be located below or beneath the electromagnetic coil 11.

[0123] Therefore, when an object is loaded onto the weighing pan 3, the current that needs to be supplied to the electromagnetic coil 11 to keep the electromagnetic coil 11 and the weighing pan 3 in the same position indicates the weight of the object loaded on the weighing pan 3.

[0124] Device 1 includes a controller 14, which is configured to control the supply of current to the electromagnetic coil 11 and determine the current that needs to be supplied to the electromagnetic coil 11 to keep the electromagnetic coil 11 and the weighing pan 3 in the same position when an object is loaded onto the weighing pan 3.

[0125] The position of the weighing pan 3, the shaft 5, or the electromagnet 11 or another component directly or indirectly connected to one of these components can be detected using a position sensor (such as an optical position sensor). For example, the position sensor can detect a predetermined position corresponding to each component when no object is loaded on the weighing pan 3. When an object is loaded on the weighing pan 3, the controller 14 can thus detect the current that needs to be supplied to the electromagnetic coil 11 to maintain each component in this position. As described above, this current indicates the weight of the object loaded on the weighing pan 3.

[0126] When an object is loaded on the weighing pan 3, device 1 can determine and output the weight of the object loaded on device 1 based on the current that needs to be supplied to the electromagnetic coil 11 to maintain each component in this position. Alternatively, device 1 can determine and output the mass of the object loaded on device 1, for example, by using a correction factor determined by device 1 performing measurements on a reference mass with a known mass or based on the known gravity "g" at the location of device 1.

[0127] The weighing pan 3, the shaft 5, the balance beam 9 and the fixed body 7 are at least partially made of a conductive material such as metal, so that there is an electrical path or conductive path from the weighing pan 3 via the shaft 5 and the balance beam 9 to the fixed body 7. In addition, the fixed body 7 is directly or indirectly electrically connected to the ground (or earth). Therefore, when a charged object is loaded on the weighing pan 3, at least some of the charges can be released (conducted) to the ground (or earth) via the weighing pan 3, the shaft 5, the balance beam 9 and the fixed body 7.

[0128] However, as described above, the resistance of one or more of the weighing pan 3, the shaft 5, the balance beam 9 and the fixed body 7 means that the charges on the object may not be completely released through this electrical path or conductive path, so that the charge (or voltage) of the object or the weighing pan 3 may change relative to the ground (or earth).

[0129] As described above, the charge on the object or the weighing pan 3 will cause an error in the measured object gravity, and thus an error in the object mass calculated based on the measured gravity. This error may still exist in the above-mentioned device 1.

[0130] Figure 2 is a schematic diagram of another device 2 for measuring the weight or mass of an object. Features that are the same or similar to those in device 1 are denoted by the same reference numerals, and their descriptions are not necessarily repeated here.

[0131] In this device 2, the weighing pan 3 and the electromagnetic coil 11 are each connected to the balance beam 4 on opposite sides of a pivot point 6 (such as a knife edge), and the balance beam 4 can pivot at the pivot point 6. Specifically, the weighing pan 3 is positioned on the balance beam 4 on the first side of the pivot point 6, while the electromagnetic coil 11 is positioned on the balance beam 4 on the second side of the pivot point 6. The electromagnetic coil 11 is located within the magnetic field of a magnet 13. The magnet 13 can be a permanent magnet or an electromagnet.

[0132] Of course, Figure 2 only shows the magnet 13 schematically, and the shape and / or structure and / or position of the magnet 13 can be different from that shown in Figure 2 shown.

[0133] In addition, Figure 2 only shows the electromagnetic coil 11 schematically, and the shape and / or structure and / or position of the electromagnetic coil 11 can be different from that shown in Figure 2 shown.

[0134] When using device 2, an object (such as a semiconductor wafer) whose weight is to be measured is placed on the weighing pan 3. The weight of the object on the weighing pan 3 creates a moment on the balance beam 4, and this moment acts to cause the balance beam 4 to rotate counterclockwise about the pivot point 6. The counterclockwise rotation of the balance beam 4 about the pivot point 6 will cause the electromagnetic coil 11 to move upward.

[0135] When an appropriate current is supplied to the electromagnetic coil 11, the electromagnetic coil 11 generates a magnetic field. The interaction between the magnetic field generated by the electromagnetic coil 11 and the magnetic field generated by the magnet 13 causes the electromagnetic coil 11 to be subjected to a force, the magnitude and direction of which depend on the magnitude and direction of the current applied to the electromagnetic coil 11.

[0136] By applying a current of appropriate magnitude and direction to the electromagnetic coil 11, the electromagnetic coil 11 can be subjected to a downward force, which generates a torque on the balance beam 4 that is equal in magnitude and opposite in direction to the torque caused by the weight of the object on the weighing pan 3 (i.e., Figure 2 the clockwise torque in ). In this case, the electromagnetic coil 11 will remain stationary and will not move upward because the two torques acting on the balance beam 4 cancel each other out, meaning there is no resultant torque.

[0137] Specifically, the appropriate current applied to the electromagnetic coil 11 can generate a magnetic attraction force between the electromagnetic coil 11 and the magnet 13. Since the magnet 13 is located below the electromagnetic coil, for example, directly below the electromagnetic coil 11, this magnetic attraction force acts on the electromagnetic coil 11 in the downward direction.

[0138] Therefore, when an appropriate current is supplied to the electromagnetic coil 11, the electromagnetic coil 11 is subjected to an attractive force from the magnet 13, and this attractive force acts on the electromagnetic coil 11 in the downward direction towards the magnet 13.

[0139] The downward force acting on the electromagnetic coil 11 and thus the torque caused by the downward force depend on the magnitude of the current applied to the electromagnet or the electromagnetic coil 11. Therefore, when an object is loaded on the weighing pan 3, the torque caused by the weight of the object on the weighing pan 3 can be determined by measuring the magnitude of the current that needs to be supplied to the electromagnetic coil 11 to keep the electromagnetic coil 11 in the same position. The position of the electromagnetic coil 11 (or another part of the electronic balance 2 that moves with the electromagnetic coil 11) can be determined or directly measured with high precision, for example, using a photodiode and a light source (not shown).

[0140] Therefore, when an object is placed on the weighing pan 3, the current that needs to be supplied to the electromagnetic coil 11 to keep the electromagnetic coil 11 in the same position is directly related to the weight of the object and can be used to calculate the weight of the object.

[0141] The controller 14 of the device 2 can perform the same functions as the controller 14 of the device 1 described above. For the sake of brevity, it will not be described again here.

[0142] When an object is loaded on the weighing pan 3, the device 2 can determine and output the weight of the object loaded on the device 2 based on the current required to be supplied to the electromagnetic coil 11 to maintain the electromagnetic coil 11 in the same position. Alternatively, the device 2 can determine and output the mass of the object loaded on the device 2, for example, by using a correction factor determined by the device 2 performing measurements on a reference mass with a known mass, or based on the known gravity "g" at the location where the device 2 is located.

[0143] The weighing pan 3, the balance beam 4, and the pivot point 6 are at least partially made of a conductive material such as metal, so that there is an electrical path or conductive path from the weighing pan 3 via the balance beam 4 to the pivot point 6. Additionally, the pivot point 6 is directly or indirectly electrically connected to the ground (or earth). Therefore, when a charged object is loaded on the weighing pan 3, at least some of the charge can be released (conducted) to the ground (or earth) via the weighing pan 3, the balance beam 4, and the pivot point 6.

[0144] However, as described above, the resistance of one or more of the weighing pan 3, the balance beam 4, and the pivot point 6 means that the charge on the object may not be completely discharged through this electrical path or conductive path, such that the charge (or voltage) of the object or the weighing pan 3 will vary with respect to the ground (or earth).

[0145] As described above, the charge on the object or the weighing pan 3 will cause an error in the measured object gravity and thus an error in the object mass calculated based on the measured gravity. Such an error may still exist in the above-mentioned device 2.

[0146] Of course, another component of the device 2 can be connected to the ground instead of the pivot point 6, so that the electrical connection to the ground does not pass through the pivot point 6. In this case, the pivot point 6 may not need to be at least partially made of a conductive material.

[0147] Figure 3 is a schematic diagram of the device 15 according to an embodiment of the present invention.

[0148] The device 15, which can have the same components as the device 1, Figure 3 in Figure 1 represents these same components with the same reference numerals as in Figure 1 and for the sake of brevity, their descriptions are not repeated here. These components can have

[0149] The difference between the device 15 and the device 1 is that the weighing pan 3 is electrically isolated from at least a part of the rest of the device 15 by an electrical insulator or electrical insulating material 17. For example, the electrical insulator or electrical insulating material 17 can include a layer of electrical insulating material.

[0150] The presence of the electrical insulator or electrical insulating material 17 means that the charge on the object loaded onto the weighing pan 3 cannot be released from the weighing pan 3 via the shaft 5 and the balance beam 9 to the fixed body 7.

[0151] More specifically, the mounting portion 23 of the weighing pan 3 and the device 15 on which the weighing pan 3 is mounted are electrically insulated from the rest of the device 15 by the electrical insulator or electrical insulating material 17.

[0152] However, the device 15 includes a low-resistance electrical connection portion 21 between the mounting portion 23 and the ground (or earth) 19. The mounting portion 23 is thus electrically connected to the ground 19 via the electrical connection portion 21. Both the weighing pan 3 and the mounting portion 23 include a conductive material, such that there is an electrical path or conduction path from the weighing pan 3 through the mounting portion 23 and the electrical connection portion 21 to the ground 19. The weighing pan 3 is thus electrically connected to the ground 19 via the mounting portion 23 and the electrical connection portion 21.

[0153] Therefore, the charge on the object loaded onto the weighing pan 3 can be discharged from the mounting portion 23 and via the electrical connection portion 21 to the ground (or earth) 19. Since the electrical connection portion 21 has a low resistance, most or all of the charge on the object can be discharged to the ground (or earth) via the electrical connection portion 21. This can reduce or prevent the problems associated with the charge on the object during measurement discussed above.

[0154] The electrical connection portion 21 has a low resistance, for example, less than or equal to 100 ohms (Ohm), or less than or equal to 10 ohms, or less than or equal to 5 ohms, or less than or equal to 2 ohms, or less than or equal to 1 ohm.

[0155] Of course, in other embodiments, the electrical connection portion 21 can be between the weighing pan 3 and the ground (or earth) 19, rather than between the mounting portion and the ground (or earth) 19.

[0156] The electrical connection portion 21 can include one or more conductive metal wires or foils, such as copper wires, or copper foils, or gold foils.

[0157] At least a part of the electrical connection portion 21 that moves or deforms or bends when an object is loaded onto the weighing pan 3 can include a conductive foil (such as a gold foil) or be made of a conductive foil (such as a gold foil) so as not to significantly restrict the movement of the weighing pan 3 when the object is loaded onto the weighing pan 3.

[0158] For example, a part of the electrical connection portion 21 that extends between the moving part of the device and the fixed part of the device can include a conductive foil (such as a gold foil) or be made of a conductive foil (such as a gold foil).

[0159] For example, a part of the electrical connection portion 21 that extends from the edge or surface of the mounting portion to the surface or edge of the fixed part of the device 15 can include a conductive foil (such as a gold foil) or be made of a conductive foil (such as a gold foil).

[0160] Device 15 includes a dynamometer. Specifically, the dynamometer may at least include, for example, a shaft 5, an electromagnet 11, a magnet 13, a balance beam 9, and a fixed body 7.

[0161] Of course, in another embodiment, device 15 may be electrically connected to the ground via components other than the fixed body 7.

[0162] Figure 4 Schematic diagram of device 16 according to another embodiment of the present invention.

[0163] Device 16, which may have the same components as device 2, has Figure 4 the same reference numerals to denote these same components as in Figure 2 and, for the sake of brevity, their description will not be repeated here. These components may have Figure 2 any of the features of the corresponding components in

[0164] Device 16 differs from device 2 in that the weighing pan 3 is electrically isolated from at least a part of the remainder of device 16 by an electrical insulator or electrically insulating material 17. For example, the electrical insulator or electrically insulating material 17 may include a layer of electrically insulating material.

[0165] The presence of the electrical insulator or electrically insulating material 17 means that the charge on an object loaded onto the weighing pan 3 cannot be released from the weighing pan 3 to the pivot point 6 via the balance beam 4.

[0166] More specifically, the weighing pan 3 and the mounting portion 23 of device 16 on which the weighing pan 3 is mounted are electrically insulated from the remainder of device 16 by the electrical insulator or electrically insulating material 17.

[0167] However, device 16 includes a low-resistance electrical connection portion 21 between the mounting portion 23 and the ground (or earth) 19. The mounting portion 23 is thus electrically connected to the ground 19 via the electrical connection portion 21. Both the weighing pan 3 and the mounting portion 23 include conductive materials such that there is an electrical path or conduction path from the weighing pan 3 through the mounting portion 23 and the electrical connection portion 21 to the ground 19. The weighing pan 3 is thus electrically connected to the ground 19 via the mounting portion 23 and the electrical connection portion 21.

[0168] Therefore, the charge on an object loaded onto the weighing pan 3 can be discharged from the mounting portion 23 and discharged to the ground (or earth) 19 via the electrical connection portion 21. Since the electrical connection portion 21 has a low resistance, most or all of the charge on the object can be discharged to the ground (or earth) via the electrical connection portion 21. This can reduce or prevent the problems associated with the charge on the object during measurement as discussed above.

[0169] The electrical connection portion 21 has a low resistance, for example, less than or equal to 100 ohms, or less than or equal to 10 ohms, or less than or equal to 5 ohms, or less than or equal to 2 ohms, or less than or equal to 1 ohm.

[0170] Of course, in other embodiments, the electrical connection portion 21 can be between the weighing pan 3 and the ground (or earth) 19, rather than between the mounting portion and the ground (or earth) 19.

[0171] The electrical connection portion 21 can include one or more conductive metal wires or foils, such as copper wires, or copper foils, or gold foils.

[0172] When an object is loaded onto the weighing pan 3, at least a part of the electrical connection portion 21 that moves or deforms or bends can include a conductive foil (such as a gold foil) or be made of a conductive foil (such as a gold foil) so that the movement of the weighing pan 3 is not significantly restricted when the object is loaded onto the weighing pan 3.

[0173] For example, a part of the electrical connection portion 21 that extends between the moving part of the device and the fixed part of the device can include a conductive foil (such as a gold foil) or be made of a conductive foil (such as a gold foil).

[0174] For example, a part of the electrical connection portion 21 that extends from the edge or surface of the mounting portion to the surface or edge of the fixed part of the device 16 can include a conductive foil (such as a gold foil) or be made of a conductive foil (such as a gold foil).

[0175] The device 16 includes a force measuring device. Specifically, the force measuring device can at least include, for example, an electromagnet 11, a magnet 13, a balance beam 4, and a pivot point 6.

[0176] Of course, in another embodiment, the device 16 can be electrically connected to the ground via other components other than the pivot point 6.

[0177] Figure 5A and Figure 5B More detailedly shows the mounting portion 23 of the device 15 or the device 16.

[0178] As Figure 5A and Figure 5B shown, the mounting portion 23 includes a plate 25 having a cylindrical boss 27. The cylindrical boss 27 is used to accommodate the shaft of the weighing pan 3 to mount the weighing pan 3 on the device 15 or the device 16.

[0179] The mounting portion 23 further includes an electrical insulator or electrical insulating material 17 located below the plate 25, such as an electrical insulating material layer. The electrical insulator or electrical insulating material 17 electrically insulates the plate 25 from another part 29 of the mounting portion 23 or the device 15 or the device 16 located below the electrical insulator or electrical insulating material 17. For example, the part 29 can include Figure 3 the top end of the shaft 5 in Figure 4a part of the balance beam 4 in, or it can be part of the mounting portion 23 or the device, which is directly or indirectly connected to Figure 3 the top end of the shaft 5 in, or directly or indirectly connected to Figure 3 the balance beam 9 in, or directly or indirectly connected to Figure 4 the balance beam 4 in.

[0180] The electrical insulator or electrical insulating material 17 is in direct contact with the bottom or lower side of the plate 25. For example, the electrical insulator or electrical insulating material 17 can be attached to or disposed on the bottom or lower side of the plate 25.

[0181] Such as Figure 5A and Figure 5B As shown, the plate 25 is mechanically connected and / or fixed to the portion 29 via one or more screws 31 or other connectors. The screws 31 pass through the electrical insulator or electrical insulating material 17, for example through corresponding holes in the electrical insulator or electrical insulating material 17. The screws 31 are formed of an electrical insulating material such that they do not provide any electrical connection between the plate 25 and the portion 29.

[0182] The plate 25 and the cylindrical boss 27 contain or are made of a conductive material such as metal.

[0183] Figure 6 Shows Figure 5A the mounting portion 23 of, on which the weighing pan 3 is mounted. Specifically, the weighing pan 3 includes a shaft 33 that is received within the cylindrical boss 27 of the mounting portion 23 to mount the weighing pan 3 on the mounting portion 23.

[0184] The mounting portion 23 can include a connector for electrically connecting the electrical connection portion 21 to the mounting portion 23.

[0185] Of course, the configuration of the device 15 or the device 16 can be different from Figure 3 or Figure 4 shown.

[0186] For example, the shaft 5 can be omitted in some embodiments. For example, the weighing pan 3 can alternatively be directly mounted on or mounted to the balance beam 9.

[0187] Additionally or alternatively, in some embodiments, the electromagnet 11 can be positioned at a different location. For example, the electromagnet 11 does not need to be located below the weighing pan 3, or as Figure 3 shown directly below the weighing pan 3, or as Figure 4 shown at the end of the balance beam 4.

[0188] Additionally or alternatively, the construction and / or positioning of the fixed body 7 and the balance beam 9 can be different from Figure 4 shown.

[0189] Additionally or alternatively, in other embodiments, different types or configurations of supports may be used to replace the weighing pan 3.

[0190] The weighing pan 3 may be configured to support wafers, such as semiconductor wafers. For example, the weighing pan 3 may be configured to support wafers having a predetermined diameter (e.g., 300 mm).

[0191] Figure 7 is a schematic diagram of a device 35 for measuring the weight or mass of an object according to an embodiment of the present invention.

[0192] For example, the device 35 may be a semiconductor wafer mass metering device.

[0193] The device 35 may include the above-described device 15 or device 16, which may have any of the features of the above-described device 15 or device 16, unless incompatible with the following features.

[0194] As Figure 7 shown, in the present embodiment, the device 15 or device 16 is housed in a measurement chamber 37 or a measurement enclosure. The measurement chamber 37 provides a controlled environment for performing weight or mass measurements using the device 15 or device 16.

[0195] The measurement chamber 37 includes a removable cover 39, which is shown in Figure 7 as separated from the measurement chamber 37. The removable cover 39 can be raised and lowered to open and close the measurement chamber 37.

[0196] The measurement chamber 37 is electrically connected to ground, as shown by the electrical connection portion 41 in Figure 7 .

[0197] The device 15 or device 16 (e.g., the housing or casing or enclosure of the device 15 or device 16) is electrically connected to the measurement chamber 37 through an electrical connection portion 43 (e.g., a metal wire). Thus, the device 15 or device 16 is electrically connected to ground via the electrical connection portion 43 and via the measurement chamber 37.

[0198] However, as described above, the support 3 and the mounting portion 23 of the device 15 or device 16 are electrically isolated from the rest of the device 15 or device 16, and thus are not electrically connected to ground via the electrical connection portion 43. Instead, the mounting portion 23 is electrically connected to the measurement chamber 37 through an additional electrical connection portion 45 (e.g., a metal wire and / or foil). Thus, the mounting portion 23 is electrically connected to ground via the electrical connection portion 45 and via the measurement chamber 37, bypassing the rest of the device 15 or device 16 and the electrical connection portion 43.

[0199] Furthermore, the removable cover 39 of the measurement chamber 37 is electrically connected to the measurement chamber 37 through an electrical connection portion 47 (e.g., a metal wire). Thus, the cover 39 is electrically connected to ground via the electrical connection portion 47 and via the measurement chamber 37.

[0200] Of course, Figure 7 only the electrical connection part is shown schematically, and the position and configuration of the electrical connection part can be different from Figure 7 that shown.

[0201] As Figure 7 shown, the device 35 further includes a plurality of sensors for sensing the atmospheric conditions inside the measurement chamber. For example, the device 35 may include one or more of a temperature sensor 49a, a pressure sensor 49b, and a humidity sensor 49c. The output of one or more of these sensors can be used to calculate the buoyancy force acting on an object on the weighing pan 3 and correct the measured weight or mass of the object for this buoyancy force to determine the absolute weight or mass of the object.

[0202] The device 35 may include a controller 51 for performing calculations, which corrects the weight or mass measured by the device 15 or the device 16 for the buoyancy force of an object on the weighing pan 3 based on the output of one or more sensors.

[0203] The device 35 can be configured to output the mass of an object, such as the absolute mass.

[0204] Features disclosed in the foregoing description, or in the following claims, or in the drawings (appropriately expressed in their specific forms, or in the means for performing the disclosed functions, or in the method or process for obtaining the disclosed results) can be used independently or in any combination of such features to implement different forms of the present invention.

[0205] Although the present invention has been described in connection with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art when the present disclosure is given. Accordingly, the above-described exemplary embodiments of the invention are considered illustrative rather than restrictive. Various changes can be made to the embodiments without departing from the spirit and scope of the present invention.

[0206] To avoid any ambiguity, any theoretical explanations provided herein are for enhancing the reader's understanding. The inventors do not wish to be bound by any of these theoretical explanations.

[0207] Any section headings used herein are for organizational purposes only and should not be construed as limiting the subject matter described.

[0208] Unless the context otherwise requires, throughout this specification including the claims which follow, the terms "comprise", "include" and variations such as "comprises", "comprising" and "including" will be understood to imply the inclusion of the stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.

[0209] It should be noted that, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" as used in the specification and the appended claims include plural referents. Ranges may be expressed herein as from "about" a particular value, and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about", it will be understood that the particular value forms another embodiment. The term "about" associated with a numerical value is optional and means, for example, + / - 10%.

Claims

1. A device for measuring the weight or mass of an object, comprising: a support for supporting the object during weight or mass measurement; and a force sensor; wherein the support is electrically isolated from at least a part of the force sensor; and wherein the support is electrically connected to the ground.

2. The device according to claim 1, wherein the device comprises an electrical insulator or electrically insulating material that electrically insulates the support from at least the part of the force sensor.

3. The device according to claim 1 or 2, wherein the device comprises an electrical path or conductive path between the support and the ground.

4. The device according to claim 3, wherein the electrical path or conductive path comprises one or more of a conductive metal wire and a conductive foil.

5. The device according to any one of the preceding claims, wherein: the device comprises a mounting portion for mounting the support onto the force sensor; and the support and the mounting portion are electrically isolated from at least the part of the force sensor.

6. The device according to claim 5, wherein the mounting portion comprises a plate having a receiving portion, and a part of the support is received within the receiving portion.

7. The device according to claim 5 or 6, wherein: the device comprises an electrical insulator or electrically insulating material that electrically insulates the support from at least the part of the force sensor; and the electrical insulator or electrically insulating material is positioned below the mounting portion.

8. The device according to any one of claims 5 to 7, wherein: the device comprises an electrical path or conductive path between the support and the ground; and the electrical path or conductive path comprises a conductor attached to the mounting portion.

9. The device according to claim 8, wherein the conductor comprises a conductive metal wire or a conductive foil.

10. The device according to any one of the preceding claims, wherein: the device comprises an electrical path or conductive path between the support and the ground; and when an object is loaded onto the support, a deformed or bent part of the electrical path or conductive path comprises a conductive foil.

11. The device according to any one of the preceding claims, wherein: the device comprises an electrical path or conductive path between the support and the ground; a part of the electrical path or conductive path extends between a moving part and a fixed part of the device; and the part of the electrical path or conductive path comprises a conductive foil.

12. The device according to any one of the preceding claims, wherein the device comprises a measurement chamber electrically connected to the ground, and wherein the support is electrically connected to the measurement chamber.

13. The device according to any one of the preceding claims, wherein the support comprises a weighing pan.

14. The device according to any one of the preceding claims, wherein the force sensor is an electromagnetic force compensation force sensor.

15. The device according to any one of the preceding claims, wherein the device further comprises one or more sensors configured to sense one or more atmospheric conditions.

16. The apparatus according to claim 15, wherein the apparatus further comprises a controller configured to calculate the weight or mass of the object based on the output of the dynamometer and the output of the one or more sensors.

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