Semiconductor Wafer Metrology Device

Abstract

An apparatus comprising: a measurement chamber having a removable lid; and a plurality of wafer support elements for supporting a wafer from below, the plurality of wafer support elements being provided on the lid.

Description

[Technical field]

[0001] The present invention relates to a weighing device for performing weight measurements on wafers. [Background technology]

[0002] Microelectronic devices are fabricated on semiconductor (e.g., silicon) wafers using a variety of techniques including, for example, deposition techniques (CVD, PECVD, PVD, etc.) and removal techniques (e.g., chemical etching, CMP, etc.) The semiconductor wafer may be further processed to change its mass, for example, by cleaning, ion implantation, lithography, etc.

[0003] Depending on the device being manufactured, each semiconductor wafer may pass sequentially through hundreds of different processing steps to build and / or remove layers and materials necessary for its final operation. In practice, each semiconductor wafer is sent down a production line. The nature of semiconductor manufacturing means that a particular processing step or sequence of steps in the production flow may be repeated in a similar or identical manner. For example, this may be the building of layers of similar metal conductors to interconnect different parts of an active circuit.

[0004] Standards have been adopted across much of the semiconductor manufacturing industry to ensure consistency and interoperability of semiconductor equipment used in different factories. For example, standards developed by Semiconductor Equipment and Materials International (SEMI) are highly prevalent in the market. One example of standardization is the size and shape of semiconductor (silicon) wafers; typically, for mass production, they are disks with a diameter of 300 mm. However, some semiconductor (silicon) wafers (typically used in older factories) are disks with a diameter of 200 mm.

[0005] The cost and complexity of the processing steps required to produce a finished silicon wafer, and the time it takes to reach the end of the production line where its operation can be adequately evaluated, have made it desirable to monitor the operation of the equipment on the production line and the quality of the wafers being processed throughout processing so that confidence in the performance and yield of the final wafer can be assured.

[0006] Wafer processing techniques typically cause mass changes at or on the surface of a semiconductor wafer. The configuration of the changes to the surface is often critical to the functionality of the device, so for quality control purposes it is desirable to evaluate the wafers during production to determine whether they have the correct configuration.

[0007] Specialized metrology tools can be used in the production flow immediately following the relevant process being monitored, typically before subsequent processing, i.e. between processing steps.

[0008] Measuring the mass change of a wafer on either side of a processing step is an attractive way to perform production wafer metrology. It is relatively low-cost, fast, and can automatically accommodate different wafer circuit patterns. In addition, it can often provide results with greater accuracy than alternative techniques. For example, for many typical materials, the thickness of material layers can be resolved down to the atomic scale. The wafer in question is weighed before and after the processing step of interest. The mass change is correlated to the performance of the production equipment and / or the desired properties of the wafer.

[0009] More accurate measurement of the mass change of the wafer allows for tighter quality control of the wafer processing.

[0010] WO 2002 / 003449 discloses an apparatus and method for investigating semiconductor wafers, in which the mass change of the wafer is determined in order to assess various properties of the wafer, e.g. to enable the fabrication of the wafer to be monitored. A common way to obtain mass measurements is to measure the force due to gravity (weight) using a very sensitive force sensor. At a moderate level of accuracy, this force can be assumed to be due only to the mass of the wafer. However, if a higher level of accuracy is required, other forces may need to be taken into account.

[0011] One such force, disclosed in WO 2002 / 003449, is caused by atmospheric buoyancy. In semiconductor metrology, semiconductor wafers are typically measured in air (i.e. not in a vacuum). Thus, the wafer displaces this volume of air, which causes an upward thrust. The upward thrust depends on the air density, which in turn depends on a number of factors including temperature, atmospheric pressure, relative humidity, and air composition. This upward thrust reduces the apparent weight of the wafer, as detected by a force sensor.

[0012] WO 2002 / 003449 discloses a method for compensating or correcting for the effects of atmospheric buoyancy. Sensors are provided to monitor temperature, pressure, and relative humidity. A processor receives measurements from these sensors and uses them to calculate air density, which can be used to compensate for buoyancy in corresponding weight measurements. The processor can calculate the buoyancy from the calculated air density, along with the weight measurements and density information for the wafer. Summary of the Invention

[0013] The inventors have recognized that if a semiconductor wafer is not flat, for example if the wafer has a curved or bent shape, or if the wafer is not supported so that it is coplanar or nearly coplanar (e.g., horizontal or nearly horizontal) during weight measurement, then weight measurements may be improper or inaccurate.

[0014] For example, if a semiconductor wafer is not supported so that it is flush or nearly flush (e.g., horizontal or nearly horizontal) during weight measurement, there can be a large deviation between the location of the edge of the wafer that would be expected if the wafer were flush and the actual location of the edge of the wafer.

[0015] In fact, it is not uncommon for semiconductor wafers to be supported non-coplanar or nearly non-coplanar during weighing.

[0016] For example, weight measurements may be performed using a load cell. When manufacturing such a load cell, the configuration and / or position and / or orientation of the load cell (and / or the housing surrounding the load cell) may be set up for optimal performance of the load cell. In this optimal setup, the load cell (and / or the housing surrounding the load cell) is often not coplanar. In other words, the weighing axis or weighing direction (the direction in which the load cell measures the weight force) of the load cell may not be vertical, and / or the top and / or bottom surface of the load cell (and / or the housing surrounding the load cell) may not be horizontal.

[0017] If the load cell is not coplanar, then the balance or weighing pan connected or coupled to the load cell and which supports the semiconductor wafer during weight measurement will also not be coplanar, and as a result the wafer will not be supported so as to be coplanar or nearly coplanar (e.g., horizontal or nearly horizontal) during weight measurement.

[0018] The deviation between the position of the edge of the wafer that would be expected if the wafer were coplanar and the actual position of the edge of the wafer can cause a number of problems. For example, in some cases, the deviation can be sufficient for the edge of the wafer to come into contact with a part of a device or apparatus, such as a part of a measurement chamber surrounding a weighing device that performs the weight measurement. This means that part of the weight of the wafer can be supported by the part of the device or apparatus, resulting in an inappropriate or inaccurate weight measurement performed on the wafer.

[0019] Additionally or alternatively, the deviation may change the spacing between a portion of the wafer, such as the edge of the wafer, and a portion of a device or apparatus, such as a portion of a measurement chamber surrounding a weighing device performing the weight measurement. In particular, the deviation may decrease the spacing between the portion of the wafer and the portion of the device or apparatus. This may increase the electrostatic force between the portion of the wafer and the portion of the device or apparatus, caused by electrostatic charges on the wafer and / or on the portion of the device or apparatus. The electrostatic force acting on the wafer may change the gravitational force measured during the weight measurement, resulting in an inappropriate or inaccurate weight measurement performed on the wafer.

[0020] Additionally or alternatively, the load cells may be coplanar, but the support (such as a balance pan or weighing pan) used to support the wafer during weight measurement may not be coplanar, for example due to variations in the manufacture of the support, which may lead to the wafer not being supported so as to be coplanar or nearly coplanar (e.g., horizontal or nearly horizontal) during weight measurement.

[0021] In addition to or instead of the problems discussed above, semiconductor wafers may not be flat, for example, they may have a curved or bent shape.

[0022] This means that there may be an uncertainty as to the location of the edge of the wafer when it is supported during the weight measurement. Thus, there may be a large deviation between the expected location of the edge of the wafer if the wafer were flat and the actual location of the edge of the wafer. This deviation may also cause one or more of the problems described above.

[0023] Aspects of the present invention may address one or more of these problems.

[0024] According to a first aspect of the present invention, there is provided a weighing device for performing a weight measurement on a wafer having a particular diameter D, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements configured to contact an underside of the wafer no greater than a distance of D / 3 from an edge of the wafer to support the wafer during the weight measurement.

[0025] According to a first aspect of the invention, the wafer is supported from underneath, closer to the edge (eg, the peripheral edge, or circumferential edge, or radially outer edge) of the wafer than is conventional.

[0026] This means that even if the wafer is not flat (e.g. the wafer is curved or bowed), the position of the wafer's edge can be better controlled and / or more clearly defined because the wafer is supported close to its edge.

[0027] In contrast, if the wafer is supported closer to the center of the wafer than in the present invention and the wafer is curved or bent, there may be significant uncertainty as to the position of the edge of the wafer, which may result in one of the further problems described above.

[0028] A metering device according to the first aspect of the invention may have any one of the following optional features, or any combination thereof, where compatible.

[0029] The wafer may be a semiconductor wafer, for example a silicon wafer.

[0030] The wafer may have a disk shape.

[0031] Performing a gravitational measurement on the wafer may include performing a gravitational force measurement on the wafer.

[0032] Performing a weight measurement on the wafer may include generating a measurement output indicative of a weight of the wafer.

[0033] The measurement output may include an electrical signal or output that corresponds to the weight being measured. For example, the magnitude of the current or voltage of the electrical signal or output may correspond to the weight being measured.

[0034] Performing a weight measurement on the wafer may include measuring the weight of the wafer or measuring the difference between the weight of the wafer and the weight of another item, such as a reference mass or a reference wafer.

[0035] Performing a weight measurement on the wafer may include measuring the difference between the weight of the wafer and the counterweight.

[0036] The weighing device may be configured to calculate information regarding the mass of the wafer based at least on the weight measurement, such as the mass of the wafer or a change in mass of the wafer.

[0037] The weighing device may comprise or be a microbalance.

[0038] The weighing device may comprise or be a weighing balance.

[0039] The weighing device may comprise or be an electronic balance.

[0040] The weighing device may comprise a force sensor or force transducer for generating a measurement output indicative of the weight of an object placed on the weighing device.

[0041] The weighing device may comprise a gravitational force sensor or transducer for generating a measurement output indicative of the weight of an object placed on the weighing device.

[0042] The weighing device may comprise a load cell for generating a measurement output indicative of the weight of an object placed on the weighing device.

[0043] The weighing device may comprise a force sensor or load cell for electromagnetic force compensation or restoration.

[0044] The weighing device is for performing a weight measurement on a wafer having a particular diameter D. In particular, the weighing device may be configured or adapted to perform a weight measurement on a wafer having a particular diameter D.

[0045] Typically, semiconductor wafer processing or metrology equipment is configured to handle semiconductor wafers of a particular diameter, such as 200 mm or 300 mm, and cannot be used for semiconductor wafers of other diameters. For example, equipment configured for 200 mm diameter wafers typically cannot be upgraded to handle 300 mm diameter wafers, and downgrading equipment configured to handle 300 mm diameter wafers typically requires refitting the equipment, for example, by modifying the wafer handling system, weighing pans, and other elements.

[0046] The support may comprise or be a dish, such as a balance dish or weighing dish.

[0047] Supporting the wafer during weight measurement means that the weight of the wafer is received by a support.

[0048] The support may alternatively be referred to as a measurement area where the wafer is placed to perform the weight measurement.

[0049] The support may be connected or coupled to a force sensor, force transducer, gravitational force sensor, gravitational force transducer, or load cell such that the gravitational force of a wafer placed on the support is transmitted from the support to the force sensor, force transducer, gravitational force sensor, gravitational force transducer, or load cell.

[0050] The support includes a plurality of contact elements configured to contact the underside of the wafer no greater than a distance D / 3 from the edge of the wafer.

[0051] The term contact element may refer to a contact part or a contact member.

[0052] The term contact element may refer to a wafer contact element, or a wafer contact part, or a wafer contact member.

[0053] The contact element may be a support element, or a support part, or a support member.

[0054] The distance may be a radial distance.

[0055] The distance may be measured along the plane of the wafer and / or along the bottom or lower surface of the wafer.

[0056] The underside of the wafer may refer to the bottom or side of the wafer, and / or the surface or side of the wafer that faces the weighing device during weight measurement, and / or the underside or side of the wafer.

[0057] Each of the plurality of contact elements is configured to contact the underside of the wafer no greater than a distance D / 3 from the edge of the wafer.

[0058] Each of the plurality of contact elements is configured to contact the underside of the wafer at a respective location on the underside of the wafer that is no greater than a distance D / 3 from the edge of the wafer.

[0059] Each of the multiple contact elements may be configured to contact the underside of the wafer at the same distance from the edge of the wafer, or different contact elements may be configured to contact the underside of the wafer at different distances from the edge of the wafer.

[0060] The edge of the wafer may refer to the circumferential edge, or circumference, or boundary, or peripheral or radially outer edge, of the underside of the wafer.

[0061] The weighing device may be configured or adapted to perform a weight measurement on a wafer having a particular diameter D.

[0062] The support may be configured or adapted to support the wafer during the weight measurement.

[0063] The weighing device may be for performing weight measurements on a 300 mm diameter wafer. Accordingly, the plurality of contact elements are configured to contact the underside of the wafer no more than 100 mm from the edge of the wafer. The plurality of contact elements may be configured to contact the underside of the wafer no more than 90 mm, or 80 mm, or 75 mm, or 70 mm, or 60 mm, or 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from the edge of the wafer.

[0064] Alternatively, the weighing device may be for performing weight measurements on a 200 mm diameter wafer. Thus, the contact elements are configured to contact the underside of the wafer no more than 67 mm (to two significant figures) from the edge of the wafer. The contact elements may be configured to contact the underside of the wafer no more than 60 mm, or 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from the edge of the wafer.

[0065] Alternatively, the weighing device may be for performing weight measurements on a 450 mm diameter wafer. Thus, the contact elements are configured to contact the underside of the wafer no more than 150 mm from the edge of the wafer. The contact elements may be configured to contact the underside of the wafer no more than 140 mm, or 130 mm, or 120 mm, or 112.5 mm, or 110 mm, or 100 mm, or 90 mm, or 80 mm, or 70 mm, or 60 mm, or 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from the edge of the wafer.

[0066] The plurality of contact elements may extend perpendicular to a major plane, or a major surface, or a major surface of the support.

[0067] There may be three contact elements. Three contact elements may be preferred because the contact points of the three contact elements configured to contact the wafer always lie in a single plane. This may mean that the wafer is stably supported by the contact elements.

[0068] There may be only three contact elements, or there may be exactly three contact elements.

[0069] Generally, the three contact elements are distributed around the centre of the support so as to form a triangle around the centre of the support (when the support is viewed perpendicular to the main plane, or main surface, or main face, of the support).

[0070] The three contact elements may be positioned to form an equilateral triangle about the centre of the support (when the support is viewed perpendicular to a major plane, or surface, or face, of the support).

[0071] The centre of a support may mean the point or position where the weighing axis or weighing direction of a weighing device (e.g. the direction in which a load cell of the weighing device measures gravitational force) passes through the support (when the support is viewed perpendicular to the main plane, or main surface, or main face of the support).

[0072] The center of the support may refer to the point or location that is located under the center of the wafer when the wafer is placed on the metrology device.

[0073] The center of the support may refer to a point or location that is located under the center of mass of the wafer when the wafer is placed on the metrology device.

[0074] However, in other embodiments, there may be a different number of contact elements, for example, there may be four or more contact elements.

[0075] There may be more than two contact elements.

[0076] The term contact element may refer to a contact member or a contact part.

[0077] The multiple contact elements may be configured to contact the underside of the wafer no greater than a distance of D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from the edge of the wafer.

[0078] Each of the plurality of contact elements may be configured to contact the underside of the wafer no more than a specified distance from the edge of the wafer.

[0079] Each of the plurality of contact elements may be configured to contact the underside of the wafer at a respective location on the underside of the wafer that is no greater than a specified distance from the edge of the wafer.

[0080] The plurality of contact elements may comprise or be pins, such as wafer support pins. For example, each of the contact elements may comprise or be a pin.

[0081] Each of the plurality of contact elements may comprise a rod or a cylinder.

[0082] The weighing device may be for performing weight measurements on wafers with a diameter of 200 mm, or 300 mm, or 450 mm. Thus, the particular diameter D may be 200 mm, or 300 mm, or 450 mm.

[0083] The plurality of contact elements may comprise contact elements of two or more different lengths, for example, each of the plurality of contact elements may have a different respective length.

[0084] There may be three contact elements (exactly three, or only three contact elements), and each of the three contact elements may have a different respective length.

[0085] There may be more than two contact elements, and the more than two contact elements may comprise contact elements of two or more different lengths.

[0086] The multiple contact elements may comprise contact elements of two or more different lengths to support the semiconductor wafer in a more coplanar or more horizontal orientation (compared to when the contact elements all have the same length), and / or to support the semiconductor wafer in a substantially or nearly coplanar or horizontal orientation, and / or to support the wafer in a coplanar or horizontal orientation.

[0087] The major planes or faces or surfaces of a support (eg, a balance pan or weighing pan) do not have to be coplanar or horizontal.

[0088] For example, the weighing device may comprise a load cell, and the load cell and / or a housing surrounding the load cell may not be coplanar. Accordingly, a support connected or coupled to the load cell may also not be coplanar.

[0089] Alternatively, the load cells may be coplanar, but the supports may not be coplanar, for example due to variations in manufacturing of the supports.

[0090] In this case, providing contact elements having different lengths means that the wafer can be supported by the support in a more coplanar or horizontal orientation than if the contact elements all had the same length.

[0091] The length of the contact element may be configured so that the top of the contact element is approximately or substantially positioned in a horizontal plane, or a nearly horizontal plane (e.g., a plane inclined less than 5 degrees relative to the horizontal), or a plane that is more coplanar and / or more nearly horizontal than the major plane or surface or major surface of the support.

[0092] The plane formed by the top of the contact element (or the best fit plane for the top of the contact element) may be more coplanar / closer to the coplanar (or horizontal) plane than the plane formed by the bottom of the contact element or the major plane or surface or major face of the support.

[0093] Thus, when the wafer is placed on the metrology device, the semiconductor wafer is supported in a more coplanar or horizontal orientation than if the contact elements all had the same length.

[0094] In general, the lengths of the contact elements may be configured and / or set and / or selected to support the wafer in a more coplanar (or horizontal) orientation (compared to when the contact elements all have the same length), or in a substantially coplanar (or horizontal) orientation, or in a coplanar (or horizontal) orientation.

[0095] The length of a contact element may refer to the distance that the contact element extends from a major planar, or face, or surface of the support in a direction perpendicular to the major planar, or face, or surface of the support.

[0096] The length of a contact element may refer to the longitudinal length or dimension of the contact element.

[0097] One or more of the multiple contact elements may have an adjustable length. For example, each of the multiple contact elements may have an adjustable length. Thus, the length of the one or more contact elements may be adjusted to achieve a desired length.

[0098] According to a second aspect of the invention there is provided an apparatus comprising a metering device according to the first aspect of the invention.

[0099] The apparatus according to the second aspect of the invention may include any of the features of the metering device according to the first aspect of the invention described above.

[0100] The apparatus according to the second aspect of the invention may have any one of the following optional features, or any combination thereof, where compatible.

[0101] The apparatus can be for determining information about the mass of the semiconductor wafer, such as the mass of the semiconductor wafer, the change in mass of the semiconductor wafer, or the difference between the mass of the semiconductor wafer and the mass of a reference mass.

[0102] The apparatus may be a semiconductor wafer mass metrology apparatus.

[0103] The equipment may be configured to handle semiconductor wafers of a particular diameter, such as 200 mm, or 300 mm, or 450 mm.

[0104] The apparatus may include a wafer transporter configured to move the wafer onto a support of the metering device. The wafer transporter may be configured to transport a wafer having a particular diameter.

[0105] The apparatus may comprise a monitoring means configured to determine the buoyant force exerted on the wafer by the atmosphere in the measurement chamber.

[0106] Calculating the mass of the semiconductor wafer may include compensating for the buoyancy force exerted on the wafer by the atmosphere in the measurement chamber.

[0107] The monitoring means may include one of a further temperature monitor, a pressure monitor and a humidity monitor (or a temperature sensor, or a pressure sensor, or a humidity sensor).

[0108] The apparatus according to the second aspect of the invention may comprise a plurality of wafer support elements for supporting the wafer from below whilst the wafer is resting on the supports.

[0109] The term wafer support element may refer to a wafer support part or a wafer support member.

[0110] The term wafer support element may refer to a wafer contacting element, a wafer contacting part, or a wafer contacting member.

[0111] That the wafer support element is for supporting the wafer from below while the wafer is placed on the support may mean that the wafer support element is for contacting the underside of the wafer to support the wafer while the wafer is placed on the support.

[0112] In other words, a wafer support element supporting the wafer from below can mean that the contact point between the wafer support element and the wafer is below or beneath the wafer and / or on the underside or bottom of the wafer.

[0113] That the wafer support element is for supporting the wafer from below while the wafer is placed on the support can mean that the wafer support element is for contacting the wafer from below or below the wafer to support the wafer while the wafer is placed on the support.

[0114] Each of the plurality of wafer support elements may be configured to contact an underside of the wafer to support the wafer while the wafer is placed on the supports.

[0115] For example, there may be three wafer support elements, or more than two wafer support elements.

[0116] The wafer support element may comprise a wafer holder or a wafer hanger.

[0117] The wafer support element can be used to support the wafer while it is transferred onto the support.

[0118] The wafer support elements may be configured to contact the wafer from below to support the wafer before it is placed on the supports.

[0119] The wafer support elements may be configured so as not to contact the wafer after it is placed on the supports.

[0120] The wafer support elements may be configured to support wafers having a diameter of 200 mm, or 300 mm, or 450 mm.

[0121] One contact element of the plurality of contact elements may be configured to contact an underside of the wafer that is 50 mm or less (when the wafer is supported by the support) from a position where one wafer support element of the plurality of wafer support elements is configured to contact an underside of the wafer (when the wafer is supported by the wafer support element).

[0122] One contact element of the plurality of contact elements may be configured to contact a position on the underside of the wafer that is 50 mm or less (when the wafer is supported by the support) from a position on the underside of the wafer at which one wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer (when the wafer is supported by the wafer support element).

[0123] In particular, if the wafer is not coplanar and / or flat, the edge of the wafer may be able to contact one or more of the wafer support elements while the wafer is resting on the weighing device, in which case a portion of the weight of the wafer may be supported by the wafer support elements, resulting in improper or inaccurate weight measurements.

[0124] In this embodiment, one contact element of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm (when the wafer is supported by the supports) from a location where one wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer (when the wafer is supported by the wafer support element). Thus, the location of the edge of the wafer may be better controlled and / or more clearly defined in the vicinity of the wafer support element, thereby preventing or reducing contact between the wafer and the wafer support element when the wafer is supported by the supports.

[0125] The 50 mm distance may be measured along the plane of the wafer and / or along the bottom or underside of the wafer.

[0126] The contact element may be configured to contact the underside of the wafer no more than 40 mm, or 30 mm, or 20 mm, or 10 mm from the location at which the wafer support element is configured to contact the underside of the wafer.

[0127] Each of the plurality of contact elements may be configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which one of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0128] Each of the plurality of contact elements may be configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which each of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0129] Each of the plurality of contact elements may be configured to contact the underside of the wafer at a respective location on the underside of the wafer that is 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm or less from a location on the underside of the wafer at which a wafer support element (or each wafer support element) of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0130] There may be three (only three or exactly three) contact elements and three (only three or exactly three) wafer support elements. Each of the three contact elements may be configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location where each of the three wafer support elements is configured to contact the underside of the wafer.

[0131] There may be more than two contact elements.

[0132] There may be more than two wafer support elements.

[0133] The number of contact elements may be the same as the number of wafer support elements. Each of the contact elements may be configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location of the wafer support element at which the respective wafer support element is configured to contact the underside of the wafer.

[0134] The apparatus may include a measurement chamber having a lid, the metrology device may be inside the measurement chamber, and the plurality of wafer support elements may be attached to or connected to or integrated into or provided on the lid.

[0135] The apparatus may include a measurement chamber having a lid, the metrology device may be inside the measurement chamber, and the plurality of wafer support elements may be on an underside of the lid, the underside of the lid being a surface of the lid that faces the inside of the measurement chamber when the lid is on the measurement chamber.

[0136] The measurement chamber may house and / or surround the metering device.

[0137] The lid may be the top or part of the measurement chamber.

[0138] A number of wafer support elements may be attached to the underside of the lid.

[0139] The lid may be removable from the measurement chamber.

[0140] The lid may be movable vertically upwards relative to the body of the measurement chamber to remove the lid from the body of the measurement chamber, and vertically downwards relative to the body of the measurement chamber to position the lid on the body of the measurement chamber.

[0141] For example, the device may include one or more actuators connected or coupled to the lid and operable to move the lid relative to the body of the measurement chamber. Movement of the lid may be controlled by a controller of the device.

[0142] The wafer support element may be configured to suspend the wafer below the bottom surface of the lid.

[0143] Thus, the wafer may be held or supported by the wafer support element below the bottom surface of the lid with a predetermined spacing between the wafer and the bottom surface of the lid.

[0144] The apparatus may be configured such that the wafer is placed onto the support from the wafer support elements when the lid is positioned over the measurement chamber (e.g. the wafer support elements and / or contact elements may be configured and / or adapted and / or arranged and / or positioned in this manner).

[0145] For example, when the lid is positioned over the measurement chamber, the contact point of the contact element may be vertically higher than the contact point of the wafer support element.

[0146] According to a third aspect of the present invention there is provided a weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement; The support includes a plurality of contact elements positioned at least 50 mm from the center of the support and configured to contact the underside of the wafer to support the wafer during weight measurement.

[0147] Thus, the multiple contact elements are capable of supporting a 300 mm semiconductor wafer closer to the edge of the wafer than previously possible.

[0148] A metering device according to the third aspect of the invention may have any of the features of the metering device according to the first aspect of the invention described above, insofar as they are incompatible with the features of the third aspect described herein.

[0149] A metering device according to the third aspect of the invention may have any one of the following optional features, or any combination thereof, where compatible.

[0150] At least 50 mm from the center of the support means greater than or equal to 50 mm, or more than or equal to 50 mm from the center of the support.

[0151] The wafer may be a semiconductor wafer, such as a silicon wafer.

[0152] The center of a support may refer to the center of the support when the support is viewed perpendicular to the main plane, main face, or main surface of the support.

[0153] The centre of the support may mean the point where the weighing axis or weighing direction of the weighing device (eg the direction in which a load cell of the weighing device measures gravitational force) passes through the support.

[0154] The center of the support may refer to the point or location on the support that is below the center of the wafer when the wafer is placed on the support.

[0155] The center of the support may refer to a point or location that is located under the center of mass of the wafer when the wafer is placed on the metrology device.

[0156] The center of the support may be a point on the support above the central shaft of the support.

[0157] The plurality of contact elements may be located at a position at least 60 mm, or at least 70 mm, or at least 75 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support.

[0158] Each of the multiple contact elements may be located the same distance from the center of the support, or each of the contact elements may be located a different respective distance from the center of the support.

[0159] The distance from the center of the support can be measured when the support is viewed perpendicular to the major plane, or main face, or main surface, of the support.

[0160] The distance from the center of the support may be, for example, the radial distance from the center of the support on a major planar, or face, or surface of the support.

[0161] The distance from the center of the support can be measured along a major planar, or major face, or major surface of the support.

[0162] There may be more than two contact elements.

[0163] The metrology device may be for performing weight measurements on a 300 mm diameter wafer.

[0164] The metrology device may be configured or adapted to perform weight measurements on a 300 mm diameter wafer.

[0165] The metering device according to the third aspect may be included in an apparatus according to the second aspect, which may include any of the features of the second aspect described above, insofar as they are incompatible with the features of the third aspect described herein.

[0166] According to a fourth aspect of the present invention, there is provided a weighing device for performing a weight measurement on a 200 mm diameter wafer, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements located at a position at least 33 mm from a centre of the support and configured to contact an underside of the wafer to support the wafer during the weight measurement.

[0167] A metering device according to the fourth aspect of the invention may have any of the features of the metering device according to the first or third aspect of the invention described above, insofar as they are incompatible with the features of the fourth aspect described herein.

[0168] A metering device according to the fourth aspect of the invention may have any one of the following optional features, or any combination thereof, where compatible.

[0169] The plurality of contact elements may be located at a distance of at least 40 mm, or at least 50 mm, or at least 60 mm, or at least 70 mm, or at least 80 mm, or at least 90 mm from the centre of the support.

[0170] There may be more than two contact elements.

[0171] The wafer may be a semiconductor wafer, such as a silicon wafer.

[0172] The metering device according to the fourth aspect may be included in an apparatus according to the second aspect, which may include any of the features of the second aspect described above, insofar as they are incompatible with the features of the fourth aspect described herein.

[0173] According to a fifth aspect of the present invention, there is provided a weighing device for performing a weight measurement on a 450 mm diameter wafer, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements located at a position at least 75 mm from a centre of the support and configured to contact an underside of the wafer to support the wafer during the weight measurement.

[0174] A metering device according to the fifth aspect of the invention may have any of the features of the metering device according to the first, third or fourth aspect of the invention described above, insofar as they are incompatible with the features of the fifth aspect described herein.

[0175] A metering device according to the fifth aspect of the invention may have any one of the following optional features, or any combination thereof, where compatible.

[0176] The wafer may be a semiconductor wafer, such as a silicon wafer.

[0177] There may be more than two contact elements.

[0178] The multiple contact elements may be located at a position at least 85 mm, or at least 95 mm, or at least 105 mm, or at least 112.5 mm, or at least 115 mm, or at least 125 mm, or at least 135 mm, or at least 145 mm, or at least 155 mm, or at least 165 mm, or at least 175 mm, or at least 185 mm, or at least 195 mm, or at least 205 mm, or at least 215 mm from the center of the support.

[0179] The metering device according to the fifth aspect may be comprised in an apparatus according to the second aspect, which may include any of the features of the second aspect described above, insofar as such features are incompatible with the features of the fifth aspect described herein.

[0180] According to a sixth aspect of the present invention, a weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement; a plurality of wafer support elements for supporting the wafer from below while the wafer is placed on the support; Equipped with one contact element of the plurality of contact elements is configured to contact an underside of the wafer no more than 50 mm (when the wafer is supported by the support) from a location at which one wafer support element of the plurality of wafer support elements is configured to contact an underside of the wafer (when the wafer is supported by the wafer support element); An apparatus is provided.

[0181] The device according to the sixth aspect of the present invention may include any of the features of the first to fifth aspects described above, provided that they are not incompatible with the features of the sixth aspect described herein.

[0182] The apparatus according to the sixth aspect of the invention may include any one of the following optional features, or any combination thereof, where compatible.

[0183] That the wafer support element is for supporting the wafer from below while the wafer is placed on the support may mean that the wafer support element is for contacting the underside of the wafer to support the wafer while the wafer is placed on the support.

[0184] In other words, a wafer support element supporting the wafer from below can mean that the contact point between the wafer support element and the wafer is below or beneath the wafer and / or on the underside or bottom of the wafer.

[0185] That the wafer support element is for supporting the wafer from below while the wafer is placed on the support can mean that the wafer support element is for contacting the wafer from below or below the wafer to support the wafer while the wafer is placed on the support.

[0186] Each of the plurality of wafer support elements may be configured to contact an underside of the wafer to support the wafer while the wafer is placed on the supports.

[0187] The contact element is configured to contact the underside of the wafer at a location on the underside of the wafer that is 50 mm or less (when the wafer is supported by the support) from a location on the underside of the wafer at which one wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer (when the wafer is supported by the wafer support element).

[0188] The wafer support elements may be configured so as not to contact the wafer after it is placed on the supports.

[0189] The contact element may be configured to contact the underside of the wafer no more than 40 mm, or 30 mm, or 20 mm, or 10 mm from the location at which the wafer support element is configured to contact the underside of the wafer.

[0190] Each of the plurality of contact elements may be configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which one of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0191] Each of the plurality of contact elements may be configured to contact the underside of the wafer no greater than a specified distance from a location at which each of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0192] Each of the plurality of contact elements may be configured to contact the underside of the wafer at a respective location on the underside of the wafer that is no greater than a specified distance from a location on the underside of the wafer at which each of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0193] There may be three (only three or exactly three) contact elements.

[0194] There may be three (only three or exactly three) wafer support elements.

[0195] Each of the three contact elements may be configured to contact the underside of the wafer no greater than a specified distance from the location at which each of the three wafer support elements is configured to contact the underside of the wafer.

[0196] There may be more than two contact elements.

[0197] There may be more than two wafer support elements.

[0198] The number of contact elements may be the same as the number of wafer support elements. Each of the contact elements may be configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location of the wafer support element at which the respective wafer support element is configured to contact the underside of the wafer.

[0199] The contact elements may be pins, for example, each of the contact elements may comprise a pin or may be a pin.

[0200] The plurality of contact elements may comprise contact elements of two or more different lengths.

[0201] The multiple contact elements may comprise contact elements of two or more different lengths to support the wafer in a more coplanar orientation during weighing.

[0202] For example, there may be three contact elements, and each of the three contact elements may have a different respective length.

[0203] There may be more than two contact elements, and the more than two contact elements may comprise contact elements of two or more different lengths.

[0204] One or more of the multiple contact elements may have an adjustable length.

[0205] The wafer may be a semiconductor wafer, for example a silicon wafer.

[0206] The weighing device may be for performing a weight measurement on a wafer having a particular diameter D, and one of the further plurality of contact elements may be configured to contact the underside of the wafer at a distance of D / 3, or D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from the edge of the wafer.

[0207] The metrology device may be for performing weight measurements on wafers with a diameter of 200 mm, or 300 mm, or 450 mm.

[0208] The weighing device may be configured and / or adapted to perform a weight measurement on a wafer having a particular diameter D.

[0209] One of the further plurality of contact elements may be configured to contact the underside of the wafer no more than 100 mm, or 90 mm, or 80 mm, or 70 mm, or 60 mm, or 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from the edge of the wafer.

[0210] One or more of the plurality of contact elements may be located at a position at least 50 mm, or at least 60 mm, or at least 70 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support.

[0211] The apparatus may include a measurement chamber having a lid, the metrology device may be inside the measurement chamber, and a plurality of wafer support elements may be attached to the lid (and / or provided on an underside of the lid).

[0212] The apparatus may be configured such that the wafer is placed onto the support from the wafer support element when the lid is positioned over the measurement chamber.

[0213] According to a seventh aspect of the present invention there is provided a weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement; the support includes a plurality of contact elements configured to contact an underside of the wafer to support the wafer during weight measurement; The plurality of contact elements includes contact elements of two or more different lengths.

[0214] A metering device according to the seventh aspect of the invention may include any of the features of the metering device according to the first, third, fourth or fifth aspects of the invention described above, insofar as they are incompatible with the features of the seventh aspect described herein.

[0215] The metering device according to the seventh aspect of the invention may include any one of the following optional features, or any combination thereof, where compatible.

[0216] The multiple contact elements may include contact elements of two or more different lengths to support the semiconductor wafer in a more coplanar orientation during weighing.

[0217] There may be more than two contact elements.

[0218] There may be exactly three contact elements, or there may be only three contact elements.

[0219] The three contact elements may have different respective lengths.

[0220] There may be more than two contact elements, and the more than two contact elements may comprise contact elements of two or more different lengths.

[0221] The wafer may be a semiconductor wafer, for example a silicon wafer.

[0222] At least one of the plurality of contact elements may have an adjustable length.

[0223] A metering device according to the seventh aspect of the invention may be comprised in an apparatus according to the second or sixth aspects of the invention described above, which may include any of the features of the second or sixth aspects described above, insofar as they are incompatible with the features of the seventh aspect described herein.

[0224] According to an eighth aspect of the present invention there is provided a weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement; the support includes a plurality of contact elements configured to contact an underside of the wafer to support the wafer during weight measurement; At least one of the plurality of contact elements has an adjustable length.

[0225] A metering device according to the eighth aspect of the present invention may include any of the features of the metering device according to the first, third, fourth, fifth or seventh aspects of the present invention described above, insofar as they are incompatible with the features of the eighth aspect described herein.

[0226] There may be more than two contact elements.

[0227] The wafer may be a semiconductor wafer, for example a silicon wafer.

[0228] A metering device according to the eighth aspect of the present invention may be comprised in an apparatus according to the second or sixth aspects of the present invention described above, which may include any of the features of the second or sixth aspects described above, insofar as they are incompatible with the features of the eighth aspect described herein.

[0229] According to a ninth aspect of the present invention, there is provided a method comprising performing a weight measurement on a semiconductor wafer having a particular diameter D, the method comprising supporting the wafer from below during the weight measurement at a distance of D / 3 or less from an edge of the wafer.

[0230] The method according to the ninth aspect may include any of the features of the first to eighth aspects described above, insofar as they are not compatible with the features of the ninth aspect described herein.

[0231] Supporting the wafer from below can mean that the contact points with the wafer are on the underside or bottom of the wafer.

[0232] Supporting the wafer from below at a distance D / 3 or less from the edge of the wafer during weight measurement may include or mean contacting the wafer at a location on the underside of the wafer that is at a distance D / 3 or less from the edge of the wafer during weight measurement.

[0233] Supporting the wafer from below no more than a distance D / 3 from the edge of the wafer during weight measurement may include or mean contacting the wafer at multiple locations on the underside of the wafer during weight measurement, each of which is no more than a distance D / 3 from the edge of the wafer.

[0234] The method may include supporting the wafer from below no more than a distance D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from the edge of the wafer.

[0235] Supporting the wafer from below at or below the specified distance from the edge of the wafer includes contacting the underside of the wafer at a location on the underside of the wafer that is at or below the specified distance from the edge of the wafer.

[0236] The method may include supporting the wafer from below using a plurality of contact elements configured to contact an underside of the wafer no more than a specified distance from an edge of the wafer.

[0237] There may be three (only three or exactly three) contact elements. There may be more than three contact elements.

[0238] The wafer may be a semiconductor wafer, such as a silicon wafer.

[0239] According to a tenth aspect of the present invention, A weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement. A method comprising: The method includes setting lengths of the plurality of contact elements to support the wafer in a more coplanar orientation during weight measurement. A method is provided.

[0240] The method according to the tenth aspect may include any of the features of the first to ninth aspects described above, insofar as they are not compatible with the features of the tenth aspect described herein.

[0241] According to an eleventh aspect of the present invention there is provided an apparatus comprising a measurement chamber having a removable lid and a plurality of wafer support elements for supporting a wafer from below, the plurality of wafer support elements being provided on the lid.

[0242] The device according to the eleventh aspect of the present invention may include any of the features of the first to tenth aspects described above, provided that they are not compatible with the features of the eleventh aspect described herein.

[0243] For example, the lid and / or wafer support element of this embodiment can have any of the features of the lid and / or wafer support element of any of the other embodiments described above, unless incompatible.

[0244] The apparatus according to the eleventh aspect of the invention may include any one of the following optional features, or any combination thereof, where compatible.

[0245] That the wafer support element is for supporting the wafer from below can mean that the wafer support element is for contacting the underside of the wafer to support the wafer.

[0246] In other words, a wafer support element supporting the wafer from below can mean that the contact point between the wafer support element and the wafer is below or beneath the wafer and / or on the underside or bottom of the wafer.

[0247] That the wafer support element is for supporting the wafer from below can mean that the wafer support element is for contacting the wafer from below or beneath the wafer to support the wafer.

[0248] Each of the plurality of wafer support elements may be configured to contact an underside of the wafer to support the wafer.

[0249] A wafer support element provided on the lid can mean that the wafer support element is positioned on the lid, attached to the lid, secured to the lid, or integral with the lid.

[0250] The wafer support element may be provided on the underside or bottom surface or side of the lid.

[0251] The underside of the lid means the side of the lid that faces the inside of the measurement chamber when the lid is positioned over the measurement chamber.

[0252] The wafer support element may be a wafer hanger.

[0253] There may be three (only three or exactly three) wafer support elements. There may be more than two wafer support elements.

[0254] The three wafer support elements can be configured to be evenly spaced about a circumference of the wafer when the wafer is supported by the three wafer support elements.

[0255] For example, three wafer support elements may be configured to form an equilateral triangle between the three wafer support elements.

[0256] The contact points of the three wafer support elements can be configured to be evenly spaced about the circumference of the wafer when the wafer is supported by the three wafer support elements.

[0257] For example, the contact points of the three wafer support elements may be configured to form an equilateral triangle between the contact points of the three wafer support elements.

[0258] The apparatus may include a weighing device for performing a weight measurement on the wafer, the weighing device being inside the measurement chamber.

[0259] The measurement chamber may house and / or surround the metering device.

[0260] The lid may be the top or part of the measurement chamber.

[0261] The lid may be movable vertically upward relative to the body of the measurement chamber to remove the lid from the body of the measurement chamber, and vertically downward relative to the body of the measurement chamber to position the lid on the body of the measurement chamber.

[0262] For example, the device may include one or more actuators connected or coupled to the lid and operable to move the lid relative to the body of the measurement chamber. Movement of the lid may be controlled by a controller of the device.

[0263] The wafer support element may be configured to suspend the wafer below the lower (bottom) surface of the lid.

[0264] Thus, the wafer may be held or supported by the wafer support element beneath the lower (bottom) surface of the lid with a predetermined spacing between the wafer and the lower surface of the lid.

[0265] The apparatus may be configured such that the wafer is loaded from the wafer support element onto the metering device when the lid is positioned over the measurement chamber (e.g. the wafer support element and / or the metering device may be configured and / or adapted and / or arranged and / or positioned in this manner).

[0266] The weighing device can include supports for supporting the wafer during weight measurement. The apparatus may be configured such that the wafer is loaded from the wafer support elements onto the supports when the lid is positioned over the measurement chamber (e.g. the wafer support elements and / or the supports may be so configured and / or adapted and / or arranged and / or positioned).

[0267] The support may include a plurality of contact elements (eg, three or more) configured to contact the underside of the wafer to support the wafer during weight measurement.

[0268] When the lid is positioned over the measurement chamber, the contact point of the contact element may be vertically higher than the contact point of the wafer support element.

[0269] The apparatus may comprise a seal located between the lid and the measurement chamber when the lid is positioned over the measurement chamber, For example, the seal may be provided on the lid and / or the body of the measurement chamber.

[0270] Each of the plurality of wafer support elements may be substantially L-shaped.

[0271] Each of the plurality of wafer support elements may be configured to extend inwardly relative to a wafer supported by the plurality of wafer support elements.

[0272] Each of the plurality of wafer support elements may be configured to extend radially inward relative to a wafer supported by the plurality of wafer support elements.

[0273] For example, each of the wafer support elements can include a first portion extending substantially vertically downward from the underside of the lid and a second portion extending substantially horizontally from the first portion, and the second portion can be positioned to extend substantially radially inward relative to a wafer supported by the wafer support element.

[0274] The second portions of the wafer support elements may be long enough so that a wafer can be inserted between any two of the wafer support elements from the side (i.e., laterally) and then lowered onto the second portions of the wafer support elements.

[0275] For example, the wafer may be supported from below by an end effector or other wafer supporter, and the end effector may be used to position the wafer between the wafer support elements and lower the wafer onto a second portion of the wafer support element.

[0276] Each wafer support element may include a protrusion, e.g., a bump or pin, for contacting an underside of the wafer when the wafer is supported by the wafer support element, thereby minimizing contact between the wafer and the wafer support elements and thus minimizing contamination of the wafer. For example, the protrusion may be located on an upper side of the second portion of the wafer hanger.

[0277] Where compatible, one or more features of any of the above-mentioned aspects of the invention may be combined in any order. [Brief description of the drawings]

[0278] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. [Figure 1] FIG. 1 is a diagram showing an apparatus according to a comparative example. [Diagram 2] FIG. 2 is a diagram showing an apparatus according to a comparative example. [Diagram 3] FIG. 3 shows an apparatus according to a first embodiment of the invention. [Figure 4]FIG. 4 shows an apparatus according to a first embodiment of the invention. [Figure 5(a)] FIG. 5(a) is a diagram showing a balance pan that can be used in the first embodiment of the present invention. [Figure 5(b)] FIG. 5(b) is a diagram showing a balance pan that can be used in the first embodiment of the present invention. [Figure 6] FIG. 6 shows an apparatus according to a second embodiment of the invention. [Figure 7] FIG. 7 shows an apparatus according to a second embodiment of the invention. [Figure 8(a)] FIG. 8(a) is a diagram showing a balance pan that can be used in the second embodiment of the present invention. [Figure 8(b)] FIG. 8(b) is a diagram showing a balance pan that can be used in the second embodiment of the present invention. [Figure 9] FIG. 9 shows an apparatus according to a third embodiment of the present invention. [Figure 10(a)] FIG. 10(a) is a diagram showing a balance pan that can be used in the third embodiment of the present invention. [Figure 10(b)] FIG. 10(b) is a diagram showing a balance pan that can be used in the third embodiment of the present invention. [Figure 11(a)] FIG. 11(a) shows a lid for a measurement chamber that can be used in embodiments of the present invention. [Figure 11(b)] FIG. 11(b) illustrates a lid for a measurement chamber that can be used in embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0279] Aspects and embodiments of the present invention will now be described with reference to the accompanying figures. Further aspects and embodiments will be apparent to those skilled in the art. All documents mentioned in this text are incorporated herein by reference.

[0280] 1 and 2 show an apparatus 1 according to a comparative example. The apparatus 1 may be a semiconductor wafer mass metrology apparatus for determining information about the mass of a semiconductor wafer, such as the mass of the semiconductor wafer, the change in mass of the semiconductor wafer, or the difference between the mass of the semiconductor wafer and the mass of a reference mass or counterweight.

[0281] The apparatus 1 comprises a measurement chamber 3. A weighing device 5 for performing gravitational measurements on semiconductor wafers 7 is accommodated in the measurement chamber 3. The measurement chamber 3 accommodates and / or surrounds the weighing device 5.

[0282] The apparatus 1 may be configured to determine the mass of the semiconductor wafer 7, the change in mass of the semiconductor wafer 7, or the difference between the mass of the semiconductor wafer 7 and the mass of a reference mass or counterweight based on at least a weight measurement performed on the semiconductor wafer 7 by the weighing device 5.

[0283] The weighing device 5 is configured to generate a measurement output indicative of a weight to be measured, for example the weight of a semiconductor wafer 7 placed on the weighing device 5. The weighing device 5 may measure the weight of the semiconductor wafer 7, or the change in weight of the semiconductor wafer 7, or the difference between the weight of the semiconductor wafer 7 and the weight of a reference mass or counterweight.

[0284] The measurement output of the metering device 5 may be an electrical signal or an electrical output that corresponds to the weight being measured. For example, the magnitude of the current or voltage of the electrical signal or output may correspond to the weight being measured.

[0285] The measurement chamber 3 can provide a controlled environment around the metering device 5. For example, the measurement chamber 3 can minimize air currents around the metering device 5. The measurement chamber 3 can additionally or alternatively maintain a substantially uniform temperature around the metering device 5. For example, the measurement chamber 3 can include a heater or cooler to maintain a substantially uniform temperature inside the measurement chamber 3, e.g., within + / - 0.1°C.

[0286] The weighing device 5 comprises a load cell 9 (gravimetric force sensor or gravimetric force transducer) configured to convert a force applied on the load cell 9 into an electrical signal or output corresponding to the force (i.e. the magnitude of the current or voltage of the electrical signal or output corresponds to the magnitude of the force).

[0287] The weighing device 5 further comprises a balance pan (or weighing pan) 11 for supporting the semiconductor wafer 7 during weight measurement. In particular, the balance pan 11 supports the weight of the semiconductor wafer 7 during weight measurement.

[0288] The balance pan 11 is coupled or connected to the load cell 9 such that a weight force applied to the balance pan 11 is applied to and measured by the load cell 9. For example, the balance pan 11 may include a shaft that is coupled or connected to the load cell 9.

[0289] The balance pan 11 includes a plurality of wafer support pins 13 (contact elements). The wafer support pins 13 extend perpendicular to a main plane or a main surface or a main face of the balance pan 11. Specifically, when the semiconductor wafer 7 is placed on the balance pan 11, the wafer support pins 13 extend perpendicular to a main plane or a main surface or a main face of the balance pan 11 that faces the semiconductor wafer 7.

[0290] In this comparative example, the balance pan 11 includes three wafer support pins 13 (exactly three, or only three wafer support pins 13), although a different number of wafer support pins 13 may be provided. For example, in other embodiments, there may be more than three wafer support pins 13.

[0291] The wafer support pins 13 are configured to come into contact with the underside of the semiconductor wafer 7 placed on the balance pan 11 in order to support the semiconductor wafer 7 during weight measurement.

[0292] The wafer support pins 13 may be positioned to form a triangle, such as an equilateral triangle, about the center of the balance pan 11 (when the balance pan 11 is viewed perpendicular to a major plane, or surface, or face, of the balance pan 11).

[0293] In this comparative example, each of the wafer support pins 13 is located within 40 mm from the center of the balance pan (when the balance pan 11 is viewed perpendicularly to the main plane, main surface, or main surface of the balance pan).

[0294] Thus, when a semiconductor wafer 7 having a diameter of 300 mm is placed on the balance pan 11, each of the wafer support pins 13 is configured to contact the underside of the semiconductor wafer 7 more than 110 mm from an edge (e.g., the outer circumferential edge or peripheral edge) of the semiconductor wafer 7.

[0295] 1 and 2, the measurement chamber 3 has a removable lid 15 (top surface). In particular, the lid 15 can be moved vertically upward relative to the body 19 of the measurement chamber 3 to remove the lid 15 from the body 19 of the measurement chamber 3, and can be moved vertically downward relative to the body 19 of the measurement chamber 3 to position the lid on the body 19 of the measurement chamber 3.

[0296] For example, the device 1 may include one or more actuators connected or coupled to the lid 15 and operable to move the lid 15 relative to the body of the measurement chamber 19. The movement of the lid 15 may be controlled by a controller of the device 1.

[0297] A plurality of wafer hangers 17 are attached to the bottom surface of the lid 15. The plurality of wafer hangers 17 are configured to contact the semiconductor wafer 7 from below so as to support the semiconductor wafer 7 while the semiconductor wafer 7 is placed on the balance pan 11.

[0298] In this comparative example, there are three wafer hangers 17, although a different number of wafer hangers 17 may be provided.

[0299] In particular, wafer hanger 17 is configured to suspend semiconductor wafer 7 below the bottom surface of lid 15 .

[0300] The number of wafer hangers 17 may be the same as the number of wafer support pins 13. Preferably, there are three wafer hangers 17 and three wafer support pins 13. There may be more than two wafer support pins 13 and more than two wafer hangers 17.

[0301] Thus, semiconductor wafer 7 is held or supported by wafer hanger 17 below the bottom surface of lid 15 with a predetermined distance between semiconductor wafer 7 and the bottom surface of lid 15 .

[0302] FIG. 2 shows the lid 15 removed from the body 19 of the measurement chamber 3 , with the semiconductor wafer 7 supported beneath the lid 15 by a wafer hanger 17 .

[0303] FIG. 1 shows the lid 15 positioned on the body 19 of the measurement chamber 3 .

[0304] As shown in FIG. 1 , the apparatus 1 is configured such that when the lid 15 is positioned on the body 19 of the measurement chamber 3, the semiconductor wafer 7 is placed on the weighing device 5 and supported by the balance pan 11 (e.g., the wafer hanger 17 and / or wafer support pins 13 are configured and / or arranged and / or positioned).

[0305] In particular, when the lid 15 is positioned on the body 19 of the measurement chamber 3, the tops of the wafer support pins 13 of the balance pan 11 are positioned vertically higher within the measurement chamber 3 than the portion of the wafer hanger 17 that is configured to contact the underside of the semiconductor wafer 7. Thus, when the lid 15 is positioned on the body 19 of the measurement chamber 3, the semiconductor wafer 7 is supported by the tops of the wafer support pins 13, rather than the portion of the wafer hanger 17 that is configured to contact the underside of the semiconductor wafer 7.

[0306] As described above, in the manufacturing process of a load cell such as load cell 9, the configuration and / or position and / or orientation of the load cell 9 (and / or the housing surrounding the load cell 9) is set up for optimal performance of the load cell 9. In this optimal setup, the load cell 9 (and / or the housing surrounding the load cell 9) is often not coplanar. In other words, the weighing axis or weighing direction (the direction in which the load cell 9 measures gravitational force) of the load cell 9 may not be vertical and / or the top and / or bottom surfaces of the load cell 9 (and / or the housing surrounding the load cell 9) may not be horizontal.

[0307] This optimum set-up may be achieved by the load cell 9 (or a housing surrounding the load cell 9) having multiple legs 21 (or supports) for supporting the load cell 9 above the bottom surface of the measurement chamber 3, the multiple legs 21 having different lengths so that the load cell 9 is not coplanar. For example, the length of one or more of the legs 21 may be adjustable such that the legs 21 can be adjusted to set up the load cell 9 for optimum performance.

[0308] Therefore, as shown in FIGS. 1 and 2, in this comparative example, the load cell 9 is not in the same plane (for the sake of explanation, the degree of inclination of the load cell 9 is exaggerated in FIGS. 1 and 2).

[0309] 1 and 2, because the load cell 9 is not coplanar, the balance pan 11 coupled or connected to the load cell 9 is also not coplanar. In other words, the main plane or surface or main face of the balance pan 11 that faces the semiconductor wafer 7 when the semiconductor wafer 7 is placed on the balance pan 11 is not coplanar or horizontal.

[0310] For example, because the load cell 9 is not coplanar, the shaft of the balance pan 11 connected to the load cell 9 may not be vertical and therefore the main plane or surface or face of the balance pan 11 may not be coplanar or horizontal.

[0311] 1, the semiconductor wafer 7 is not coplanar or horizontal when it is placed on the balance pan 11. In other words, the main plane or main surface or main face of the semiconductor wafer 7 is not coplanar or horizontal.

[0312] As shown in FIG. 1, if the balance pan 11, and therefore the semiconductor wafer 7, is not coplanar, there can be a large deviation between the position of the edge of the semiconductor wafer 7 that would be expected if the semiconductor wafer 7 were coplanar or level, and the actual position of the edge of the semiconductor wafer 7.

[0313] This deviation can cause a number of problems, as explained above. For example, in some cases, this deviation can be sufficient to cause an edge of the semiconductor wafer 7 to come into contact with one or more of the wafer hangers 17 while the semiconductor wafer 7 is resting on the balance pan 11. This means that part of the weight of the semiconductor wafer 7 is supported by one or more of the wafer hangers 17, thus causing an incorrect weight measurement.

[0314] Additionally or alternatively, this deviation may mean that the semiconductor wafer 7 comes into contact with a part of the measuring chamber 3, such as the lid 15 or the body 19, or another part of the apparatus 1. This means that part of the weight of the semiconductor wafer 7 is supported by a part of the measuring chamber 3 or another part of the apparatus 1, thus making the weight measurement incorrect.

[0315] The apparatus 1 may comprise monitoring means configured to determine the buoyancy force exerted on the wafer by the atmosphere in the measurement chamber 3. For example, the apparatus may comprise sensors that monitor the temperature, pressure and relative humidity in the measurement chamber 3. The controller 22 or processor of the apparatus 1 may be configured to receive measurements from these sensors and use them to calculate the air density, which can be used to compensate for buoyancy in the weight measurements performed by the weighing device 5.

[0316] Thus, the apparatus 1 may be configured to calculate the mass of the semiconductor wafer 7 based on the measurement output of the weighing device 5 and a calculation of the buoyant force exerted on the semiconductor wafer 7 by the atmosphere in the measurement chamber 3 .

[0317] The apparatus 1 and / or the metrology device 5 may be configured or adapted to handle semiconductor wafers having a particular diameter, for example 200 mm, 300 mm, or 450 mm.

[0318] In this embodiment, the apparatus 1 and / or the metrology device is configured to handle semiconductor wafers with a diameter of 300 mm.

[0319] For example, the wafer hanger 17 and / or balance pan 11 may be configured or adapted to handle semiconductor wafers having a particular diameter.

[0320] Figures 3 and 4 show an apparatus 23 according to a first embodiment of the invention. Apparatus 23 is a modified version of comparative example apparatus 1 shown in Figures 1 and 2 and described above. Apparatus 23 may therefore have any of the features of the comparative example shown in Figures 1 and 2 and / or described above, unless they are compatible with and / or replaced by the modifications described below.

[0321] In particular, as explained below, apparatus 23 differs from comparative apparatus 1 in having a balance pan 27 that is different from balance pan 11 of apparatus 1. Any (one, more than one, or all) of the other features of apparatus 23 may be the same as comparative apparatus 1. For the sake of brevity, these features will not be repeated here. Corresponding features are indicated using the same reference numbers in Figures 3 and 4.

[0322] In particular, in apparatus 23, the weighing device 5 of comparative example apparatus 1 is replaced with a weighing device 25 having a balance pan 27 different from the balance pan 11 of weighing device 5. Any (one, more than one, or all) of the other features of weighing device 25 may be the same as weighing device 5 of apparatus 1. For example, weighing device 25 may include the same load cell 9 as weighing device 5 and may include the same plurality of legs 21 as weighing device 5.

[0323] The balance pan 27 includes a plurality of wafer support pins 29. The wafer support pins 29 extend perpendicular to a main plane or a main surface or a main face of the balance pan 27. Specifically, when the semiconductor wafer 7 is placed on the balance pan 27, the wafer support pins 29 extend perpendicular to a main plane or a main surface or a main face of the balance pan 27 that faces the semiconductor wafer 7.

[0324] In this embodiment, the balance pan 27 includes three wafer support pins 29 (exactly three, or only three wafer support pins 29). Of course, in other embodiments, there may be a different number of wafer support pins 29. For example, in other embodiments, there may be more than three wafer support pins 29.

[0325] The wafer support pins 29 are configured to come into contact with the lower surface of the semiconductor wafer 7 placed on the balance pan 27 in order to support the semiconductor wafer 7 during weight measurement.

[0326] As in the comparative example, in this embodiment the load cell 9 is not coplanar, in other words the weighing axis of the load cell 9 may not be vertical and / or the top and / or bottom surface of the load cell 9 (and / or the housing surrounding the load cell 9) may not be horizontal.

[0327] For example, because the load cell 9 is not coplanar, the shaft of the balance pan 27 connected to the load cell 9 may not be vertical and therefore the main plane or surface or face of the balance pan 27 may not be coplanar or horizontal.

[0328] Because the load cells 9 are not coplanar, the balance pan 27 coupled or connected to the load cells 9 is also not coplanar. In other words, the major plane or surface or main face of the balance pan 27 that faces the semiconductor wafer 7 when the semiconductor wafer 7 is placed on the balance pan 27 is not coplanar or horizontal.

[0329] However, in this embodiment, wafer support pins 29 include wafer support pins 29 of at least two different lengths. In other words, the distance that wafer support pins 29 extend vertically from the major plane or main surface or face of balance pan 27 includes at least two different distances. For example, each of wafer support pins 29 can have a different length and extend vertically different distances from the major plane or main surface or face of balance pan 27.

[0330] There may be three wafer support pins 29, and each of the three wafer support pins 29 may have a different respective length.

[0331] Each of the wafer support pins 29 may have a fixed length, or alternatively, one or more of the wafer support pins 29 may have an adjustable length.

[0332] The length of the wafer support pins 29 may be configured so that the tops of the wafer support pins 29 are approximately or substantially positioned in a horizontal plane, or a nearly horizontal plane (e.g., a plane inclined less than 5 degrees relative to the horizontal), or a plane that is more coplanar and / or more nearly horizontal than the major plane or surface or major surface of the balance pan 27.

[0333] The plane formed by the tops of the wafer support pins 29 (or the best fit plane for the tops of the wafer support pins 29) may be more coplanar / closer to the coplanar (or horizontal) plane than the plane formed by the bottoms of the wafer support pins 29 or the major plane or surface or major face of the balance pan 27.

[0334] Wafer support pins 29 of different lengths can support the wafer 7 in a more coplanar and / or more horizontal orientation than would be the case if the wafer support pins 29 all had the same length.

[0335] Therefore, when the semiconductor wafer 7 is placed on the metrology device 25, the semiconductor wafer is closer to being flush or horizontal than in the comparative example.

[0336] In general, the lengths of the wafer support pins 29 may be configured and / or set and / or selected to support the semiconductor wafer 7 in a more coplanar (or horizontal) orientation, or in a substantially coplanar (or horizontal) orientation, or in a coplanar (or horizontal) orientation (compared to when the wafer support pins 29 all have the same length).

[0337] Thus, contact between the edge of the semiconductor wafer 7 and the wafer hanger 17, or with parts of the measurement chamber 3 such as the lid 15 or the body 19, or with other parts of the apparatus 1, can be prevented in this embodiment.

[0338] In this embodiment, the distance between each of the wafer support pins 29 and the center of the balance pan 27 (when the balance pan 27 is viewed perpendicular to the main plane, main surface, or main surface of the balance pan 27) is not particularly limited and may be different from that of the comparative example.

[0339] Figures 5(a) and 5(b) show a balance pan 27 that can be used in the first embodiment of the present invention. Figure 5(a) shows the balance pan 27 when viewed perpendicular to the main plane, main surface, or main surface of the balance pan 27. Figure 5(b) shows the balance pan 27 when viewed from the side.

[0340] 5(a) and 5(b), the balance pan 27 includes three wafer support pins 29 (or just three, or only three wafer support pins 29) including at least two different lengths of wafer support pins 29. The wafer support pins 29 extend perpendicular to a major plane, or surface, or face, of the balance pan 27.

[0341] The wafer support pins 29 are each connected to a respective arm 30 that extends radially outward from a central region of the balance pan 27 (when the balance pan 27 is viewed perpendicular to a major planar, or surface, or face, of the balance pan 27). The wafer support pins 29 extend perpendicular to the arms 30.

[0342] Each of the three wafer support pins 29 may have a different respective length (thus there are wafer support pins 29 of three different lengths).

[0343] 6 and 7 show an apparatus 31 according to a second embodiment of the invention.

[0344] Apparatus 31 is a modified version of comparative example apparatus 1 shown in Figures 1 and 2 and described above. Apparatus 31 may therefore have any of the features of the comparative example shown in Figures 1 and 2 and / or described above, unless they are compatible with and / or replaced by the modifications described below. Corresponding features are indicated using the same reference numbers in Figures 6 and 7.

[0345] In particular, as described below, apparatus 31 differs from comparative apparatus 1 in that it has a balance pan 35 that is different from balance pan 11 of apparatus 1. Any (one, more than one, or all) of the other features of apparatus 31 may be the same as comparative apparatus 1.

[0346] In particular, in apparatus 31, the weighing device 5 of comparative example apparatus 1 is replaced with a weighing device 33 having a balance pan 35 different from the balance pan 11 of weighing device 5. Any (one, more than one, or all) of the other features of weighing device 33 may be the same as weighing device 5 of apparatus 1. For example, weighing device 33 may include the same load cell 9 as weighing device 5 and may include the same plurality of legs 21 as weighing device 5.

[0347] The balance pan 35 includes a plurality of wafer support pins 37. The wafer support pins 37 extend perpendicular to a main plane or a main surface or a main face of the balance pan 35. Specifically, when the semiconductor wafer 7 is placed on the balance pan 35, the wafer support pins 37 extend perpendicular to a main plane or a main surface or a main face of the balance pan 35 that faces the semiconductor wafer 7.

[0348] In this embodiment, the balance pan 35 includes three wafer support pins 37 (exactly three, or only three wafer support pins 37). Of course, in other embodiments, there may be a different number of wafer support pins 37. For example, in other embodiments, there may be more than three wafer support pins 37.

[0349] The wafer support pins 37 are configured to come into contact with the lower surface of the semiconductor wafer 7 placed on the balance pan 35 in order to support the semiconductor wafer 7 during weight measurement.

[0350] As in the comparative example, in this embodiment the load cell 9 is not coplanar, in other words the weighing axis of the load cell 9 may not be vertical and / or the top and / or bottom surface of the load cell 9 (and / or the housing surrounding the load cell 9) may not be horizontal.

[0351] Because the load cells 9 are not coplanar, the balance pan 35 coupled or connected to the load cells 9 is also not coplanar. In other words, the main plane or surface or face of the balance pan 35 that faces the semiconductor wafer 7 when the semiconductor wafer 7 is placed on the balance pan 35 is not coplanar or horizontal.

[0352] For example, because the load cell 9 is not coplanar, the shaft of the balance pan 35 connected to the load cell 9 may not be vertical and therefore the main plane or surface or face of the balance pan 35 may not be coplanar or horizontal.

[0353] However, in this embodiment, the wafer support pins 37 include at least two different lengths of wafer support pins 37. In other words, the distance that the wafer support pins 37 extend vertically from the major plane or main surface or face of the balance pan 35 includes at least two different distances. For example, each of the wafer support pins 37 can have a different length and extend vertically different distances from the major plane or main surface or face of the balance pan 35.

[0354] There may be three wafer support pins 37, and each of the three wafer support pins 37 may have a different respective length.

[0355] Each of the wafer support pins 37 may have a fixed length, or alternatively, one or more of the wafer support pins 37 may have an adjustable length.

[0356] The length of the wafer support pins 37 may be configured so that the tops of the wafer support pins 37 are approximately or substantially positioned in a horizontal plane, or a nearly horizontal plane (e.g., a plane inclined less than 5 degrees relative to the horizontal), or a plane that is more coplanar and / or more nearly horizontal than the major plane or surface or major surface of the balance pan 35.

[0357] The plane formed by the tops of the wafer support pins 37 (or the best fit plane for the tops of the wafer support pins 37) may be more coplanar / closer to the coplanar (or horizontal) plane than the plane formed by the bottoms of the wafer support pins 37 or the major plane or surface or major surface of the balance pan 35.

[0358] Wafer support pins 37 of different lengths can support the wafer 7 in a more coplanar and / or more horizontal orientation than would be the case if the wafer support pins 37 all had the same length.

[0359] Therefore, when the semiconductor wafer 7 is placed on the measuring device 33, the semiconductor wafer 7 is closer to being flush or horizontal than in the comparative example.

[0360] In general, the lengths of the wafer support pins 37 may be configured and / or set and / or selected to support the semiconductor wafer 7 in a more coplanar (or horizontal) orientation, or in a substantially coplanar (or horizontal) orientation, or in a coplanar (or horizontal) orientation (compared to when the wafer support pins all have the same length).

[0361] Thus, contact between the edge of the semiconductor wafer 7 and the wafer hanger 17, or with parts of the measurement chamber 3 such as the lid 15 or the body 19, or with other parts of the apparatus 1, can be prevented in this embodiment.

[0362] Additionally, in this embodiment, the balance pan 35 is configured so that the wafer support pins 37 contact the underside of the wafer 7 near an edge of the semiconductor wafer 7 (e.g., an outer circumferential edge or peripheral edge), or near the edge of the semiconductor wafer 7, as is conventional.

[0363] For example, the balance pan 35 may be configured so that each of the wafer support pins 37 contacts the underside of the semiconductor wafer 7 no more than 100 mm, or 90 mm, or 80 mm, or 75 mm, or 70 mm, or 60 mm, or 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from the edge of the semiconductor wafer 7 (for a 300 mm diameter wafer).

[0364] In practice, semiconductor wafers are often not flat. For example, they may have a curved or bent shape. When the semiconductor wafer is supported near the center of the semiconductor wafer, as in the comparative example described above, this can lead to significant uncertainty regarding the location of the edge of the semiconductor wafer. As described above, deviations between the location of the edge of the semiconductor wafer 7 that would be expected if the semiconductor wafer 7 were coplanar or horizontal, and the actual location of the edge of the semiconductor wafer 7, can cause problems that may lead to inappropriate weight measurements performed by the weighing device.

[0365] In this embodiment, the semiconductor wafer 7 is supported near its edge. Thus, even if the semiconductor wafer 7 is curved or bent, the position of the edge of the semiconductor wafer 7 is controlled and / or well-defined. This can prevent or reduce the problems described above.

[0366] As mentioned above, one problem that can occur when there is a large deviation between the location of the edge of the semiconductor wafer 7 that would be expected if the semiconductor wafer 7 were flush or level, and the actual location of the edge of the semiconductor wafer 7, is that the edge of the semiconductor wafer 7 comes into contact with one or more of the wafer hangers 17 while the semiconductor wafer 7 is resting on the balance pan 11. This means that some of the weight of the semiconductor wafer 7 will be supported by one or more of the wafer hangers 17, thus resulting in an incorrect weight measurement.

[0367] Thus, in this embodiment, the wafer support pins 37 may be configured to contact the underside of the semiconductor wafer 7 (when the semiconductor wafer 7 is supported by the balance pan 35) close to where the wafer hanger 17 contacts the underside of the semiconductor wafer 7 (when the semiconductor wafer 7 is supported by the wafer hanger 17). Thus, the position of the edge of the semiconductor wafer 7 is controlled and / or well-defined at the location of the wafer hanger 17, thereby reducing or preventing contact between the edge of the semiconductor wafer 7 and the wafer hanger 17 while the semiconductor wafer 7 is resting on the balance pan 35.

[0368] Figures 8(a) and 8(b) show a balance pan 35 that can be used in a second embodiment of the present invention. Figure 8(a) shows the balance pan 27 as viewed perpendicular to the main plane, or main surface, or main surface of the balance pan 27. Figure 8(b) shows the balance pan 27 as viewed from the side.

[0369] 8(a) and 8(b), the balance pan 35 includes three wafer support pins 37 (or just three, or only three wafer support pins 37) including at least two different lengths of wafer support pins 37. The wafer support pins 37 extend perpendicular to a major plane, or surface, or face, of the balance pan 35.

[0370] The wafer support pins 37 are each connected to a respective arm 30 that extends radially outward from a central region of the balance pan 35 (when the balance pan 35 is viewed perpendicular to a major planar, or surface, or face, of the balance pan 35). The wafer support pins 37 extend perpendicular to the arms 30.

[0371] Each of the three wafer support pins 37 may have a different respective length (thus there are wafer support pins 37 of three different lengths).

[0372] Figure 9 shows an apparatus 39 according to a third embodiment of the invention. Apparatus 39 is a modified version of comparative example apparatus 1 shown in Figures 1 and 2 and described above. Apparatus 39 may therefore have any of the features of the comparative example shown in Figures 1 and 2 and / or described above, unless they are compatible with and / or replaced by the modifications described below.

[0373] In particular, as explained below, apparatus 39 differs from comparative apparatus 1 in having a balance pan 43 that is different from balance pan 11 of apparatus 1. Any (one, more than one, or all) of the other features of apparatus 39 may be the same as comparative apparatus 1. For the sake of brevity, these features will not be repeated here. Corresponding features are indicated using the same reference numerals in FIG. 9.

[0374] In particular, in apparatus 39, the weighing device 5 of comparative example apparatus 1 is replaced with a weighing device 41 having a balance pan 43 different from the balance pan 11 of weighing device 5. Any (one, more than one, or all) of the other features of weighing device 41 may be the same as weighing device 5 of apparatus 1. For example, weighing device 41 may include the same load cell 9 as weighing device 5 and may include the same plurality of legs 21 as weighing device 5.

[0375] The balance pan 43 includes a plurality of wafer support pins 45. The wafer support pins 45 extend perpendicular to a main plane or a main surface or a main face of the balance pan 43. Specifically, when the semiconductor wafer 7 is placed on the balance pan 43, the wafer support pins 45 extend perpendicular to a main plane or a main surface or a main face of the balance pan 43 that faces the semiconductor wafer 7.

[0376] In this embodiment, the balance pan 43 includes three wafer support pins 45 (exactly three, or only three wafer support pins 45). Of course, in other embodiments, there may be a different number of wafer support pins 45. For example, in other embodiments, there may be more than three wafer support pins 45.

[0377] The wafer support pins 45 are configured to come into contact with the lower surface of the semiconductor wafer 7 placed on the balance pan 43 in order to support the semiconductor wafer 7 during weight measurement.

[0378] In this embodiment, all of the wafer support pins 45 have the same length (or substantially the same length).

[0379] For example, in this embodiment, the load cell 9 may be coplanar, as is the balance pan 43.

[0380] Similar to the second embodiment, in this embodiment, the balance pan 43 is configured so that the wafer support pins 45 contact the underside of the semiconductor wafer 7 near an edge (eg, a circumferential or peripheral edge) of the wafer 7.

[0381] For example, the balance pan 43 may be configured so that each of the wafer support pins 45 contacts the underside of the semiconductor wafer 7 no more than 100 mm, or 90 mm, or 80 mm, or 70 mm, or 60 mm, or 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from the edge of the semiconductor wafer (for a 300 mm diameter wafer).

[0382] For example, the balance pan 43 may be configured so that each of the wafer support pins 45 is located at a position at least 50 mm, or at least 60 mm, or at least 70 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support (for a 300 mm diameter wafer).

[0383] Additionally, similar to the second embodiment, in this embodiment, the wafer support pins 45 may be configured to contact the underside of the semiconductor wafer 7 near the location where the wafer hanger 17 contacts the underside of the semiconductor wafer 7 when the semiconductor wafer 7 is supported by the wafer hanger 17.

[0384] Figures 10(a) and 10(b) show a balance pan 43 that can be used in a third embodiment of the present invention. Figure 10(a) shows the balance pan 43 when viewed perpendicular to the main plane, main surface, or main surface of the balance pan 43. Figure 10(b) shows the balance pan 43 when viewed from the side.

[0385] 10(a) and 10(b), the balance pan 43 includes three wafer support pins 45 (or just three, or only three wafer support pins 45) that all have the same length. The wafer support pins 45 extend perpendicular to a major plane, or surface, or face, of the balance pan 43.

[0386] The wafer support pins 45 are each connected to a respective arm 30 that extends radially outward from a central region of the balance pan 43 (when the balance pan 43 is viewed perpendicular to a major planar, or surface, or face, of the balance pan 43). The wafer support pins 45 extend perpendicular to the arms 30.

[0387] Figures 11(a) and 11(b) show a lid for a measurement chamber that can be used in an embodiment of the present invention. The lid shown in Figures 11(a) and 11(b) may correspond to the lid of any of the embodiments described above, for example the lid 15 of any of Figures 1 to 10.

[0388] The lid shown in Figures 11(a) and 11(b) may be used as a lid for any of the embodiments described above.

[0389] 11(a) and 11(b), the lid 15 includes three wafer hangers 17 (either exactly three or only three wafer hangers 17) for supporting the wafers 7. The lid 15 and wafer hangers 17 may have any of the features of the lid 15 and wafer hangers 17 described above.

[0390] The three wafer hangers 17 are evenly distributed around the circumference of the wafer 7, for example forming an equilateral triangle between the three wafer hangers 17.

[0391] In particular, the contact points of the three wafer hangers 17 for contacting and supporting the wafer 7 may be evenly distributed around the circumference of the wafer 7, for example forming an equilateral triangle between the contact points of the three wafer hangers 17.

[0392] The wafer hanger 17 is substantially L-shaped and extends inwardly relative to the wafer 7 .

[0393] In particular, in this embodiment, each wafer hanger 17 includes a first portion extending substantially vertically downward from the underside of the lid 15 and a second portion extending substantially horizontally and radially inward from the first portion relative to the wafer 7.

[0394] Of course, in other embodiments, the second portion or portions of the wafer hanger 17 may not extend radially inward. For example, the second portion or portions of the wafer hanger 17 may be at an acute angle relative to the radial direction of the wafer.

[0395] In one embodiment, the second portion of the first wafer hanger 17 may be in a radial direction of the wafer, and the second portions of the second and third wafer hangers 17 may be perpendicular to the second portion of the first wafer hanger 17.

[0396] The second portions of the wafer hangers 17 are long enough so that the wafer 7 can be inserted between any two of the wafer hangers 17 from the side (i.e., laterally) and then lowered onto the second portions of the wafer hangers 17. For example, the wafer 7 may be supported from below by an end effector or other wafer supporter, and the end effector may be used to position the wafer 7 between the wafer hangers 17 and lower the wafer 7 onto the second portions of the wafer hangers 17.

[0397] Each wafer hanger 17 may include protrusions, such as bumps or pins, for contacting the underside of the wafer 7 when the wafer 7 is supported by the wafer hanger 17. This may minimize contact between the wafer 7 and the wafer hanger 17, and therefore minimize contamination of the wafer 7. For example, the protrusions may be located on an upper side of the second portion of the wafer hanger 17.

[0398] The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, are expressed in their specific form, or in terms of means for performing a disclosed function, or in terms of a method or process for obtaining a disclosed result, and can, where appropriate, be used separately or in any combination of such features to realize the invention in various of its forms.

[0399] While the present invention has been described in conjunction with the above exemplary embodiments, many equivalent modifications and variations will be apparent to those skilled in the art given this disclosure. Accordingly, the exemplary embodiments of the invention described above are considered to be illustrative rather than limiting. Various changes can be made to the described embodiments without departing from the spirit and scope of the invention.

[0400] For the avoidance of any doubt, any theoretical explanations provided herein are provided for the purpose of facilitating the understanding of the reader, and the inventors do not wish to be bound by any of these theoretical explanations.

[0401] Any section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

[0402] Throughout this specification, including the claims which follow, unless the context requires otherwise, the words "comprise" and "include", as well as variations such as "comprises", "comprising" and "including", will be understood to mean the inclusion of certain integers or steps or groups of integers or steps but not the exclusion of any other integers or steps or groups of integers or steps.

[0403] It should be noted that, as used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from "about" one particular value and / or to "about" another particular value. When such a range is expressed, another embodiment includes from the one particular value and / or to the other particular value. Similarly, when values ​​are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another embodiment. The term "about" with respect to numerical values ​​is optional and may mean, for example, + / - 10%.

[0404] Other aspects and / or embodiments of the invention are set out in the following numbered clauses.

[0405] 1. A weighing device for performing a weight measurement on a wafer having a specific diameter D, said weighing device comprising a support for supporting said wafer during said weight measurement, the support includes a plurality of contact elements configured to contact an underside of the wafer no greater than a distance D / 3 from an edge of the wafer to support the wafer during the weight measurement. Metering device.

[0406] 2. A metering device according to clause 1, comprising: the plurality of contact elements are configured to contact the underside of the wafer no greater than a distance of D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from the edge of the wafer.

[0407] 3. A metering device according to clause 1 or 2, The plurality of contact elements comprises pins.

[0408] 4. A weighing device according to any one of clauses 1 to 3, The weighing device is for performing weight measurements on wafers of diameter 200 mm, or 300 mm, or 450 mm.

[0409] 5. A weighing device according to any one of clauses 1 to 4, A metering device, wherein the plurality of contact elements comprises contact elements of two or more different lengths.

[0410] 6. A metering device according to clause 5, comprising: A metering device, wherein the plurality of contact elements comprises contact elements of two or more different lengths to support the wafer in a more coplanar orientation.

[0411] 7. A weighing device according to any one of clauses 1 to 6, A metering device, wherein one or more of the plurality of contact elements has an adjustable length.

[0412] 8. A weighing device according to any one of clauses 1 to 7, a plurality of wafer support elements for supporting the wafer from below while the wafer is placed on the support; Equipped with a contact element of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm from a location where a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer; Device.

[0413] 9. Apparatus according to clause 8, comprising: the contact element is configured to contact the underside of the wafer no more than 40 mm, or 30 mm, or 20 mm, or 10 mm from the location where the wafer support element is configured to contact the underside of the wafer.

[0414] 10. A device according to clause 8 or 9, wherein each of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0415] 11. The device according to any one of clauses 8 to 10, The apparatus includes a measurement chamber having a lid; the metering device is inside the measuring chamber; the plurality of wafer support elements are attached to the lid; Device.

[0416] 12. A device according to clause 11, comprising: The apparatus is configured such that the wafer is placed onto the support from the wafer support element when the lid is positioned over the measurement chamber.

[0417] 13. A weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement; the support includes a plurality of contact elements positioned at least 50 mm from a center of the support and configured to contact an underside of the wafer to support the wafer during the weight measurement. Metering device.

[0418] 14. A metering device according to clause 13, comprising: A metering device, wherein the plurality of contact elements are located at a position at least 60 mm, or at least 70 mm, or at least 75 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support.

[0419] 15. A weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement; a plurality of wafer support elements for supporting the wafer from below while the wafer is placed on the support; Equipped with a contact element of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm from a location where a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer; Device.

[0420] 16. The device according to clause 15, the contact element is configured to contact the underside of the wafer no more than 40 mm, or 30 mm, or 20 mm, or 10 mm from the location where the wafer support element is configured to contact the underside of the wafer.

[0421] 17. A device according to clause 15 or 16, wherein each of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer.

[0422] 18. The device according to any one of clauses 15 to 17, The apparatus, wherein the plurality of contact elements comprises pins.

[0423] 19. The device according to any one of clauses 15 to 18, The apparatus, wherein the plurality of contact elements comprises contact elements of two or more different lengths.

[0424] 20. The device according to clause 19, The apparatus, wherein the plurality of contact elements comprises two or more contact elements of different lengths to support the wafer in a more coplanar orientation during the weight measurement.

[0425] 21. The device according to any one of clauses 15 to 20, The apparatus, wherein one or more of the plurality of contact elements has an adjustable length.

[0426] 22. The device according to any one of clauses 15 to 21, the weighing device is for performing a weight measurement on a wafer having a specific diameter D; a further one of the plurality of contact elements is configured to contact an underside of the wafer no greater than a distance of D / 3, or D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from an edge of the wafer; Device.

[0427] 23. The device according to any one of clauses 15 to 22, The apparatus, wherein one or more of the plurality of contact elements is located at a position at least 50 mm, or at least 60 mm, or at least 70 mm, or at least 75 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support.

[0428] 24. The device according to any one of clauses 15 to 23, The apparatus includes a measurement chamber having a lid; the metering device is inside the measuring chamber; the plurality of wafer support elements are attached to the lid; Device.

[0429] 25. The device according to clause 24, The apparatus is configured such that the wafer is placed onto the support from the wafer support element when the lid is positioned over the measurement chamber.

[0430] 26. A weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement; the support comprises a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement; the plurality of contact elements includes contact elements of two or more different lengths; Metering device.

[0431] 27. A weighing device according to clause 26, comprising: A weighing device, wherein the plurality of contact elements comprises two or more contact elements of different lengths to support the wafer in a more coplanar orientation during the weight measurement.

[0432] 28. A metering device according to clause 26 or 27, A metering device, wherein at least one of the plurality of contact elements has an adjustable length.

[0433] 29. A weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement; the support comprises a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement; At least one of the plurality of contact elements has an adjustable length. Metering device.

[0434] 30. Performing weight measurements on wafers having a particular diameter D A method comprising: the method includes supporting the wafer from below at a distance D / 3 or less from an edge of the wafer during the weight measurement; method.

[0435] 31. Providing a weighing device for performing a weight measurement on a wafer, the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement. A method comprising: the method includes setting lengths of the plurality of contact elements to support the wafer in a more coplanar orientation during the weight measurement. method.

Claims

1. a measurement chamber having a removable lid; a plurality of wafer support elements for supporting a wafer from below, the plurality of wafer support elements being provided on the lid; An apparatus comprising:

2. 2. The apparatus of claim 1, The apparatus, wherein the wafer support element is disposed on an underside of the lid.

3. 3. An apparatus according to claim 1 or claim 2, comprising: The apparatus, wherein the wafer support element is a wafer hanger.

4. The device according to any one of claims 1 to 3, an apparatus wherein there are exactly three said wafer support elements.

5. 5. The apparatus of claim 4, The apparatus, wherein the contact points of the three wafer support elements are configured to be equally spaced about a circumference of the wafer when the wafer is supported by the three wafer support elements.

6. An apparatus according to any one of claims 1 to 5, The apparatus, wherein the lid is a top surface of the measurement chamber.

7. An apparatus according to any one of claims 1 to 6, the lid is movable vertically upward relative to the body of the measurement chamber to remove the lid from the body of the measurement chamber, and is movable vertically downward relative to the body of the measurement chamber to position the lid on the body of the measurement chamber.

8. 8. The apparatus of claim 7, The apparatus comprises one or more actuators connected or coupled to the lid and operable to move the lid relative to the body of the measurement chamber.

9. An apparatus according to any one of claims 1 to 8, the wafer support element is configured to suspend the wafer below the lower surface of the lid.

10. An apparatus according to any one of claims 1 to 9, the apparatus includes a weighing device for performing a weight measurement on the wafer; the metering device is inside the measuring chamber; Device.

11. 11. The apparatus of claim 10, The apparatus is configured such that the wafer is loaded from the wafer support element onto the metering device when the lid is positioned over the measurement chamber.

12. 12. Apparatus according to claim 10 or claim 11, comprising: the weighing device comprises a support for supporting the wafer during the weight measurement; the apparatus is configured such that the wafer is loaded onto the support from the wafer support element when the lid is positioned over the measurement chamber. Device.

13. 13. The apparatus of claim 12, The support comprises a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement.

14. 14. The apparatus of claim 13, When the lid is positioned over the measurement chamber, a contact point of the contact element is vertically higher than a contact point of the wafer support element.

15. An apparatus according to any one of claims 1 to 14, comprising: The apparatus includes a seal located between the lid and the measurement chamber when the lid is positioned over the measurement chamber.

16. An apparatus according to any one of claims 1 to 15, The apparatus, wherein each of the plurality of wafer support elements is substantially L-shaped.

17. An apparatus according to any one of claims 1 to 16, comprising: An apparatus, wherein each of the plurality of wafer support elements is configured to extend inwardly relative to a wafer supported by the plurality of wafer support elements.

18. An apparatus according to any one of claims 10 to 14, comprising: the weighing device is for performing a weight measurement on a wafer having a specific diameter D, the weighing device comprising a support for supporting the wafer during the weight measurement; the support includes a plurality of contact elements configured to contact an underside of the wafer no greater than a distance D / 3 from an edge of the wafer to support the wafer during the weight measurement. Device.

19. 20. The apparatus of claim 18, the plurality of contact elements are configured to contact the underside of the wafer no greater than a distance of D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from the edge of the wafer.

20. 20. Apparatus according to claim 18 or claim 19, comprising: The apparatus, wherein the plurality of contact elements comprises pins.

21. An apparatus according to any one of claims 18 to 20, comprising: The apparatus, wherein the metrology device is for performing weight measurements on wafers having a diameter of 200 mm, or 300 mm, or 450 mm.

22. An apparatus according to any one of claims 18 to 21, comprising: The apparatus, wherein the plurality of contact elements comprises contact elements of two or more different lengths.

23. 23. The apparatus of claim 22, The apparatus, wherein the plurality of contact elements comprises contact elements of two or more different lengths to support the wafer in a more coplanar orientation.

24. An apparatus according to any one of claims 18 to 23, comprising: The apparatus, wherein one or more of the plurality of contact elements has an adjustable length.

25. An apparatus according to any one of claims 18 to 24, comprising: the plurality of wafer support elements for supporting the wafer from below while the wafer is placed on the support; a contact element of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm from a location where a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer; Device.

26. 26. The apparatus of claim 25, The apparatus, wherein the contact element is configured to contact the underside of the wafer no more than 40 mm, or 30 mm, or 20 mm, or 10 mm from the location where the wafer support element is configured to contact the underside of the wafer.

27. 27. Apparatus according to claim 25 or claim 26, comprising: wherein each of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer.

28. An apparatus according to any one of claims 10 to 14, comprising: the weighing device comprises a support for supporting the wafer during the weight measurement; the support includes a plurality of contact elements positioned at least 50 mm from a center of the support and configured to contact an underside of the wafer to support the wafer during the weight measurement. Device.

29. 29. The apparatus of claim 28, The apparatus, wherein the plurality of contact elements are located at a position at least 60 mm, or at least 70 mm, or at least 75 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support.

30. An apparatus according to any one of claims 10 to 14, comprising: the weighing device comprising a support for supporting the wafer during the weight measurement, the support comprising a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement; the plurality of wafer support elements for supporting the wafer from below while the wafer is placed on the support; a contact element of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm from a location where a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer; Device.

31. 31. The apparatus of claim 30, The apparatus, wherein the contact element is configured to contact the underside of the wafer no more than 40 mm, or 30 mm, or 20 mm, or 10 mm from the location where the wafer support element is configured to contact the underside of the wafer.

32. 32. Apparatus according to claim 30 or claim 31, comprising: wherein each of the plurality of contact elements is configured to contact the underside of the wafer no more than 50 mm, or 40 mm, or 30 mm, or 20 mm, or 10 mm from a location at which a wafer support element of the plurality of wafer support elements is configured to contact the underside of the wafer.

33. An apparatus according to any one of claims 30 to 32, comprising: The apparatus, wherein the plurality of contact elements comprises pins.

34. An apparatus according to any one of claims 30 to 33, comprising: The apparatus, wherein the plurality of contact elements comprises contact elements of two or more different lengths.

35. 35. The apparatus of claim 34, The apparatus, wherein the plurality of contact elements comprises two or more contact elements of different lengths to support the wafer in a more coplanar orientation during the weight measurement.

36. An apparatus according to any one of claims 30 to 35, comprising: The apparatus, wherein one or more of the plurality of contact elements has an adjustable length.

37. An apparatus according to any one of claims 30 to 36, comprising: the weighing device is for performing a weight measurement on a wafer having a specific diameter D; a further one of the plurality of contact elements is configured to contact an underside of the wafer no greater than a distance of D / 3, or D / 4, or D / 5, or D / 6, or D / 7, or D / 8, or D / 9, or D / 10, or D / 11, or D / 12, or D / 13, or D / 14, or D / 15, or D / 16, or D / 17, or D / 18, or D / 19, or D / 20 from an edge of the wafer; Device.

38. An apparatus according to any one of claims 30 to 37, comprising: The apparatus, wherein one or more of the plurality of contact elements is located at a position at least 50 mm, or at least 60 mm, or at least 70 mm, or at least 75 mm, or at least 80 mm, or at least 90 mm, or at least 100 mm, or at least 110 mm, or at least 120 mm, or at least 130 mm, or at least 140 mm from the center of the support.

39. An apparatus according to any one of claims 10 to 14, comprising: the weighing device comprises a support for supporting the wafer during the weight measurement; the support comprises a plurality of contact elements configured to contact an underside of the wafer to support the wafer during the weight measurement; the plurality of contact elements includes contact elements of two or more different lengths; Device.

40. 40. The apparatus of claim 39, The apparatus, wherein the plurality of contact elements comprises two or more contact elements of different lengths to support the wafer in a more coplanar orientation during the weight measurement.

41. 41. Apparatus according to claim 39 or claim 40, comprising: At least one of the plurality of contact elements has an adjustable length.

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