Semiconductor wafer quality measurement device and semiconductor wafer quality measurement method

Abstract

A semiconductor wafer quality measurement device comprises: a measurement chamber for measuring the weight and / or mass of a semiconductor wafer; a first temperature changing component for changing the temperature of the semiconductor wafer before the semiconductor wafer is transferred to the measurement chamber; and a first temperature sensor for sensing a first temperature, wherein the first temperature is: the temperature of the first temperature changing component; or the temperature of the semiconductor wafer when the semiconductor wafer is on the first temperature changing component, or when the semiconductor wafer leaves the first temperature changing component.

Description

Technical Field

[0001] The invention relates to a semiconductor wafer quality measurement device and a semiconductor wafer quality measurement method.

[0002] In particular, the present invention relates to a semiconductor wafer quality metrology device and a semiconductor wafer quality metrology method, in which the temperature of a temperature changing component for changing the temperature of a semiconductor wafer before the semiconductor wafer is transferred to a measurement area is measured, or the temperature of a semiconductor wafer whose temperature is changed by the temperature changing component is measured. Background Art

[0003] 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 in a manner that alters its quality (e.g., by cleaning, ion implantation, photolithography, etc.).

[0004] Depending on the device being manufactured, each semiconductor wafer may sequentially undergo hundreds of different processing steps to build up and / or remove layers and materials necessary for its final operation. In practice, each semiconductor wafer passes through a production line.

[0005] The cost and complexity of the processing steps required to produce finished silicon wafers, and the time it takes to reach the end of the production line where its operation can be properly evaluated, has led to a need to monitor the operation of the equipment on the production line and the quality of the wafers processed throughout the process, so that confidence in the performance and yield of the final wafer can be ensured.

[0006] Wafer processing techniques often cause quality variations in semiconductor wafers (e.g., at or on the surface of the semiconductor wafer or in the bulk of the semiconductor wafer). The altered configuration of the semiconductor wafer is often critical to the function of the device, so for quality control purposes, the wafers need to be evaluated during production to determine whether they have the correct configuration.

[0007] The measurement of wafer mass variations on either side of a processing step is an attractive approach to achieving production wafer metrology. It is relatively low cost, high speed, and can automatically adapt to different wafer circuit patterns. In addition, it can often provide higher accuracy results than alternative techniques. For example, on many typical materials, the thickness of the material layer can be resolved to the atomic level. The wafer in question is weighed before and after the processing step of interest. The variation in mass is correlated to the performance of the production equipment and / or the desired properties of the wafer.

[0008] Processing steps performed on a semiconductor wafer can result in small changes in the mass of the semiconductor wafer, which may need to be measured with high precision. For example, removing a small amount of material from the surface of a semiconductor wafer may reduce the mass of the semiconductor wafer by a few milligrams, and it may be desirable to measure this change with a resolution of ±100 μg or better.

[0009] At these high measurement accuracy levels, errors in the measurement output caused by temperature variations in the temperature of the semiconductor wafer or the measurement balance being measured may become significant. For example, a temperature difference of about 0.005°C between the semiconductor wafer and the measurement balance or housing may result in an error (or mass variation) of about 5 μg in the determined mass of the semiconductor wafer. Temperature variations between different parts of the measurement device (i.e., temperature non-uniformities, which are caused, for example, by thermal loading of the semiconductor wafer measured using the measurement device) will result in errors in the measurement output. In addition, if the semiconductor wafer has a temperature higher than the measurement housing of the measurement device, air currents (e.g., convective air currents) may be generated in the air in the measurement housing, which may affect the measurement output. In addition, the air in the measurement housing may be heated, thereby changing its density and pressure and, therefore, the buoyancy that the air exerts on the semiconductor wafer. This may also affect the measurement output. The magnitude of these effects is generally considered to be negligible and is ignored (or not detected) in lower precision mass measurements (e.g., measurements performed with milligram resolution).

[0010] Temperature changes that occur slowly over relatively long periods of time (e.g., on the order of hours) can be substantially accounted for by periodically calibrating the measurement device, or can be substantially eliminated by making comparative measurements. However, in the same manner, temperature changes that occur more rapidly (e.g., due to high heat loads from multiple semiconductor wafers) can be more difficult to account for or eliminate.

[0011] The temperature of a semiconductor wafer just after being processed in a production line may be 400-500°C or higher. After processing, the semiconductor wafer may be loaded into a front opening unified box (FOUP) together with other recently processed semiconductor wafers (e.g., 25 in total) to be transferred between different processing positions in the production line. When the FOUP arrives at a weighing device for weighing the semiconductor wafer, the temperature of the semiconductor wafer may still be very high, such as 70°C or higher. In contrast, the temperature of the weighing device may be approximately 20°C. Therefore, there may be a significant temperature difference between the semiconductor wafer and the weighing device. As discussed above, a significant temperature difference between the semiconductor wafer and the weighing device may result in errors in weight measurement. For high-precision weight measurements, even errors caused by very small temperature differences (e.g., less than 1°C, such as 0.001°C) may be significant.

[0012] WO02 / 02449 describes a semiconductor wafer mass metrology method that aims to reduce errors in measurement output caused by temperature changes in the measuring balance or the semiconductor wafer being measured. In the method described in WO02 / 02449, the semiconductor wafer is removed from a front opening unified box (FOUP) and placed on a passive heat transfer plate that is thermally coupled to the chamber of a weighing device, and then placed on the measurement area of ​​the weighing device. The passive heat transfer plate equalizes the temperature of the semiconductor wafer with the temperature of the chamber to within ±0.1°C. When the semiconductor wafer is loaded into the measurement chamber, this temperature equalization can reduce the potential errors discussed above. Therefore, compared to a method in which the semiconductor wafer is not temperature-equalized before measurement, the method can make the measurement output more accurate.

[0013] WO2015 / 082874 discloses that in the method described in WO02 / 02449, there may be a significant heat load on the chamber of the weighing device. For example, when a series of weight measurements are performed on a series of semiconductor wafers (wherein the semiconductor wafers are cooled from about 70° C. to about 20° C. by a heat transfer plate before the weight measurements are performed), there may be a heat load of the order of tens of watts, such as a heat load of about 50W-100W, such as a heat load of 75W (assuming about 60 wafers per hour) on the chamber of the weighing device.

[0014] This heat load can cause the temperature of the weighing device (e.g., the temperature of the scale of the weighing device) to increase or become non-uniform, which can cause corresponding errors in the weight measurements performed by the weighing device, as discussed above. In addition, such heat load can cause airflow (e.g., convective airflow) and changes in air density and pressure around the scale, which can also cause corresponding errors in the weight measurements performed by the weighing device. As a result, the accuracy of the weighing device can be reduced. These effects can be significant when performing high-precision measurements (e.g., measurements with an accuracy of approximately ±100 μg or better). For example, when using the weighing device to measure a first (or single isolated) semiconductor wafer, changes in the measurement output can be observed due to convective airflow and air density changes caused by the temperature difference between the semiconductor wafer and the weighing device.

[0015] WO 2015 / 082874 discloses removing a large portion of the heat load from the semiconductor wafer before using a heat transfer plate to equalize the temperature of the semiconductor wafer with the temperature of the weighing device to reduce the heat load on the weighing device.

[0016] Therefore, during temperature equalization, the temperature of the thermal transfer plate should not change significantly, and thus, the temperature of the semiconductor wafer will more precisely / accurately equalize to the desired temperature (ie, the original temperature of the thermal transfer plate).

[0017] In the embodiment disclosed in WO2015 / 082874, an active heat transfer plate is used to remove most of the heat load from the semiconductor wafer, and then a passive heat transfer plate is used to equalize the temperature of the semiconductor wafer with the temperature of the measurement chamber, which is mounted on the upper surface of the measurement chamber and is in thermal equilibrium with the measurement chamber. In the specific example disclosed in WO2015 / 082874, the heat transfer plate is an aluminum plate that is bolted to the measurement chamber using bolts with high thermal conductivity. Summary of the invention

[0018] The present inventors have recognized that in the arrangement discussed above, the temperature of the heat transfer plate, and therefore the temperature of the semiconductor wafer after having been cooled by the heat transfer plate, may be different from the temperature of the measurement chamber, thus causing the various measurement errors discussed above when measuring the semiconductor wafers. This is due to the high heat load on the heat transfer plate when cooling many hot semiconductor wafers.

[0019] The present inventors have recognized that the accuracy of semiconductor wafer quality measurement can be improved by measuring the temperature of a temperature changing component for changing the temperature of a semiconductor wafer, or measuring the temperature of a semiconductor wafer whose temperature is changed by the temperature changing component, before the semiconductor wafer is transferred to a measurement chamber.

[0020] Therefore, in most general terms, the present invention provides a semiconductor wafer quality measurement device or method, wherein the temperature of a temperature changing component for changing the temperature of a semiconductor wafer is measured before the semiconductor wafer is transferred to a measurement chamber; or the temperature of a semiconductor wafer whose temperature is changed by the temperature changing component is measured.

[0021] As discussed below, there are various ways in which measured temperature can be used to improve the accuracy of semiconductor wafer quality metrology.

[0022] According to a first aspect of the present invention, there is provided a semiconductor wafer quality metrology device, comprising:

[0023] a measuring chamber for measuring the weight and / or mass of a semiconductor wafer;

[0024] a first temperature changing member for changing the temperature of the semiconductor wafer before transferring the semiconductor wafer to the measurement chamber; and

[0025] A first temperature sensor is used to sense a first temperature, wherein the first temperature is:

[0026] the temperature of the first temperature changing component; or

[0027] The temperature of the semiconductor wafer when the semiconductor wafer is on the first temperature change member, or when the semiconductor wafer leaves the first temperature change member.

[0028] Therefore, in the first aspect of the present invention, the temperature of the first temperature change member is measured, or the temperature of the semiconductor wafer is measured when the semiconductor wafer is on the first temperature change member or when it is away from the first temperature change member.

[0029] The device according to the first aspect of the present invention may optionally include any one of the following optional features, or any combination of the following optional features where combinable.

[0030] Typically, the first temperature changing component will be used to reduce the temperature of the semiconductor wafer. In other words, the first temperature changing component is typically a cooling portion. However, alternatively, the first temperature changing component may be a heating portion configured to heat the semiconductor wafer to increase the temperature of the semiconductor wafer.

[0031] Typically, the semiconductor wafer will be transferred into the measurement chamber immediately after leaving the first temperature change component, e.g. without any intermediate steps, in particular without any intentional further active or passive cooling of the semiconductor wafer. This can be achieved by means of an apparatus having a suitably configured transfer mechanism. For example, a transfer device can be provided which is configured to transfer the semiconductor wafer directly from the first temperature change component into the measurement chamber.

[0032] When there is no physical contact between the semiconductor wafer and the first temperature change member, it can be considered that the semiconductor wafer has left the first temperature change member.

[0033] The measuring chamber may partially or completely surround the measuring region.

[0034] The measurement area may include a weighing device, such as a load cell, for outputting information indicative of the mass and / or weight of the semiconductor wafer.

[0035] The first temperature changing component can be used to passively cool the semiconductor wafer. Passive cooling means that the first temperature changing component does not include any powered cooling device / equipment, such as a thermoelectric cooling device, such as a Peltier. Alternatively, the first temperature changing component can be used to actively cool the semiconductor wafer, such as using a powered cooling device / equipment, such as a thermoelectric cooling device, such as a Peltier.

[0036] Alternatively, as discussed above, the first temperature changing component may alternatively be used to passively or actively warm the semiconductor wafer.

[0037] The apparatus may further comprise a second temperature changing component for actively cooling the semiconductor wafer. Active cooling means that the second temperature changing component comprises a powered cooling device, such as a thermoelectric cooling device, such as a Peltier.

[0038] Alternatively, the second temperature changing component may be used to actively heat the semiconductor wafer, for example using a powered heater or heating element.

[0039] Alternatively, the apparatus may further include a second temperature changing component for passively cooling the semiconductor wafer. For example, the second temperature changing component may include an air-cooled passive heat transfer plate. Air cooling of the passive heat transfer plate may be achieved by, for example, blowing air over the passive heat transfer plate using a fan.

[0040] Alternatively, the second temperature changing component may be used to passively heat the semiconductor wafer.

[0041] Alternatively, the second temperature changing component may be configured to change the temperature of the semiconductor wafer by bringing the semiconductor wafer into thermal equilibrium with an air flow over or through the second temperature changing component.

[0042] The second temperature changing device can be used to remove a large portion of the heat load from the semiconductor wafer before the semiconductor wafer is cooled by the first temperature changing device. Thus, the heat load on the first temperature changing device caused by cooling the semiconductor wafer is reduced.

[0043] Alternatively, the second temperature changing device may cool the semiconductor wafer to a temperature slightly lower than the temperature of the first temperature changing device, and then the first temperature changing device may heat the semiconductor wafer.

[0044] Alternatively, the second temperature changing device may be used to add a majority of the heat load to the semiconductor wafer before the semiconductor wafer is heated or cooled by the first temperature changing device. Again, the heat load on the first temperature changing device due to heating or cooling the semiconductor wafer is thereby reduced.

[0045] The reduced heat load on the first temperature changing device means that any temperature change of the first temperature changing device due to the heat load is reduced. In this way, the temperature of the semiconductor wafer can be controlled more accurately using the first temperature changing device. This can allow the temperature of the semiconductor wafer in the measurement chamber and / or the temperature (and / or temperature uniformity) of the measurement chamber to be controlled more accurately or more precisely than without the second temperature changing component. As a result, semiconductor wafer quality metrology can be performed more accurately.

[0046] For example, where the temperature of the semiconductor wafer is controlled to be substantially the same as the temperature of the measurement chamber (which is typically the case), any errors caused by temperature differences can be minimized because the temperature differences can be minimized.

[0047] The first temperature changing component and the second temperature changing component may be thermally insulated from each other, for example separated by a thermal insulator such as an air gap or a layer of thermally insulating material.

[0048] Alternatively, the second temperature changing component may form part of a separate apparatus from the apparatus of the first aspect of the invention.Thus, the second temperature changing component may be provided in conjunction with the apparatus of the first aspect.

[0049] The temperature changing component may be any device that can be used to increase or decrease (ie, change) the temperature of a semiconductor wafer, such as a heating unit / heater or a cooling unit / cooler.

[0050] The terms "first" and "second" used with respect to the first temperature changing device and the second temperature changing device are used only to distinguish the temperature changing devices and do not indicate the order of the temperature changing devices or the temperature changes of the semiconductor wafer caused by them. In fact, it is clear from the discussion below that when the second temperature changing device is present, the temperature of the semiconductor wafer is first changed using the second temperature changing device and then the temperature of the semiconductor wafer is further changed using the first temperature changing device. Therefore, in this arrangement, the second temperature change occurs before the first temperature change.

[0051] The second temperature changing component can cause a second temperature change in the temperature of the semiconductor wafer, the second temperature change comprising at least 80%, or at least 90%, or at least 95%, or at least 99% of the sum of the second temperature change and the first temperature change of the temperature of the semiconductor wafer caused by the first temperature changing component. Thus, a large portion of the heat load of the semiconductor wafer can be removed from or added to the semiconductor wafer by the second temperature changing component. As a result, when used to cause the first change in the temperature of the semiconductor wafer, the heat load on the first temperature changing component is reduced, and the temperature of the semiconductor wafer can be matched to the desired temperature more precisely / accurately.

[0052] Causing a second change in the temperature of the semiconductor wafer may include changing the temperature of the semiconductor wafer to be within ±3°C of a predetermined measurement temperature (e.g., the temperature of the measurement chamber), or within ±2°C, or within ±1°C, or within ±0.1°C. In other words, the second change in the temperature of the semiconductor wafer may bring the temperature of the semiconductor wafer close to the predetermined measurement temperature (i.e., within a few degrees Celsius), so that the first temperature changing component need only cause a small change in the temperature of the semiconductor wafer (corresponding to adding a small heat load to or removing a small heat load from the semiconductor wafer).

[0053] In the present invention, the temperature of the first temperature change member may be measured when the semiconductor wafer is on the first temperature change member, or when the semiconductor wafer is off the first temperature change member.

[0054] Monitoring the temperature of the first temperature change component while the semiconductor wafer is on the first temperature change component may provide information about the temperature difference between the temperature change component and the semiconductor wafer when the semiconductor wafer first reaches the first temperature change component.

[0055] For example, the first temperature sensor can be configured to detect a change in the temperature of the first temperature change component caused by the semiconductor wafer, and / or a maximum temperature of the first temperature change component caused by the semiconductor wafer. In particular, when there is a difference between the temperature of the semiconductor wafer and the temperature of the first temperature change component when the semiconductor wafer is loaded on the first temperature change component, an initial spike in the temperature of the first temperature change component may occur. This initial spike can be detected and / or measured in the present invention and can provide information about the incoming wafer temperature or about the difference between the incoming wafer temperature and the temperature of the first temperature change component.

[0056] The temperature of the semiconductor wafer as it leaves the first temperature changing component may provide information about the temperature difference between the semiconductor wafer and the measurement chamber when the semiconductor wafer is loaded into the measurement chamber, which, as discussed above, affects the accuracy of measurements performed on the semiconductor wafer.

[0057] The semiconductor wafer quality metrology apparatus may further include a control unit configured to control an operation of the apparatus based on the sensed first temperature and / or based on a change in the sensed first temperature.

[0058] For example, the control unit may be configured to generate an alarm based on the sensed first temperature and / or based on a change in the sensed first temperature.

[0059] For example, when the sensed temperature of the first temperature changing component is greater than a predetermined value, the device may sound an alarm.

[0060] Alternatively, an alarm may be generated when the sensed temperature of the first temperature changing component changes by more than a predetermined value.

[0061] The alarm is to warn the operator of the device so that the operator is aware of the temperature / temperature change.

[0062] The alarm may be a visible and / or audible and / or tactile alarm.

[0063] The present invention may include using the detected change in the sensed temperature of the first temperature changing component to calculate the incoming temperature of the wafer whose temperature is changed by the first temperature changing component. When it is determined that the temperature of the incoming wafer is greater than a predetermined threshold or less than a predetermined threshold, an alarm may be triggered. For example, this may indicate that the temperature change step prior to the temperature change caused by the first temperature changing component was ineffective, causing the temperature of the semiconductor wafer entering the first temperature changing component to be too high or too low (remaining substantially constant for the first temperature changing component). For example, this may indicate that the second temperature changing component discussed above has failed (damaged or not functioning properly).

[0064] The inventors have discovered that there is a correlation between the error of the mass metrology measurement performed on the semiconductor wafer and the temperature difference between the temperature of the first temperature changing component or the semiconductor wafer and the temperature of the measurement chamber before the semiconductor wafer is loaded into the measurement chamber. Therefore, the comparison of the temperature of the first temperature changing component or the semiconductor wafer and the temperature of the measurement chamber before the semiconductor wafer is loaded into the measurement chamber provides useful information that can be used to improve the accuracy of the mass metrology of the semiconductor wafer.

[0065] Therefore, the apparatus may further comprise a device or unit configured to determine a difference between the sensed first temperature and the second temperature, ie the temperature of the measurement chamber.

[0066] The apparatus may further comprise a control unit configured to control the operation of the apparatus based on a difference between the sensed first temperature and the second temperature (ie the temperature of the measurement chamber).

[0067] Alternatively or additionally, the control unit may be configured to control the operation of a separate device or apparatus based on a difference between the sensed first temperature and the second temperature, ie the temperature of the measurement chamber.

[0068] The apparatus may include a second temperature sensor configured to measure a second temperature of the measurement chamber.

[0069] The second temperature of the measurement chamber may be measured simultaneously with the measurement of the first temperature.

[0070] Typically, both the first temperature and the second temperature will be measured at the same time or shortly after the semiconductor wafer leaves the first temperature changing device and just before the semiconductor wafer is loaded into the measurement chamber. In this case, the first temperature represents the temperature of the semiconductor wafer when the semiconductor wafer is loaded into the measurement chamber.

[0071] Alternatively, the temperature of the measurement chamber may be precisely controlled to a predetermined temperature, in which case the second temperature sensor may not be required.

[0072] For example, the control unit may be a processor or a computer.

[0073] As an example of the present invention, the control unit may be configured to generate an alarm based on a difference between the first temperature and the second temperature.

[0074] For example, the device may sound an alarm when there is any difference between the first temperature and the second temperature, or when the difference between the first temperature and the second temperature is greater than a predetermined threshold.

[0075] The alarm is to alert an operator of the device so that the operator is aware of the difference between the first temperature and the second temperature.

[0076] The alarm may be a visible and / or audible and / or tactile alarm.

[0077] Alternatively or additionally, the control unit may be configured to correct the quality measurement of the semiconductor wafer based on a difference between the first temperature and the second temperature and a predetermined relationship between the difference between the first temperature and the second temperature and a quality measurement error.

[0078] As discussed above, the inventors have discovered that there is a correlation between errors in mass metrology measurements performed on semiconductor wafers and the temperature difference between the temperature of the first temperature changing component or semiconductor wafer and the temperature of the measurement chamber before the semiconductor wafer is loaded into the measurement chamber.

[0079] Thus, when the correlation is defined by a predetermined relationship, the difference between the first temperature and the second temperature and the predetermined relationship may be used to calculate or determine a corresponding error in a quality metrology measurement performed on the semiconductor wafer.

[0080] The predetermined relationship may be in the form of, for example, an equation, a function, a graph, a look-up table, or a database.

[0081] The predetermined relationship may be derived from a plurality of quality metrology measurements of one or more semiconductor wafers for different values ​​of the difference between the first temperature and the second temperature, and the known quality of the semiconductor wafers.

[0082] A number of mass metrology measurements can be performed using the apparatus in question.

[0083] The predetermined relationship is typically stored in a memory of the device.

[0084] Additionally, or alternatively, where a second temperature changing unit is provided, the second temperature changing unit may be controlled based on the difference between the first temperature and the second temperature. For example, where the first temperature is greater than the second temperature, the amount of active cooling provided by the second temperature changing unit may be increased, for example to act to reduce the difference between the first temperature and the second temperature.

[0085] The first temperature changing component may include a first heat transfer plate thermally coupled to the measurement chamber.

[0086] The first heat transfer plate is usually a passive heat transfer plate. A passive heat transfer plate means that the heat transfer plate is not cooled or heated by a cooling / heating element, but only receives its temperature from the surrounding ambient environment.

[0087] The first heat transfer plate can be substantially in thermal equilibrium with the measurement chamber. Thermal equilibrium is defined as a temperature difference between the two elements not exceeding 0.1°C.

[0088] The first heat transfer plate is typically a plate or block of material having a high thermal mass.The first heat transfer plate is typically a plate or block of material having a high thermal mass and a high thermal conductivity.

[0089] For example, the first heat transfer plate may be a metal (eg, aluminum) plate or block.

[0090] The first heat transfer plate may be provided on or integrated with the outer surface of the measurement chamber.

[0091] The first heat transfer plate may be bolted to the outer surface of the measurement chamber, for example using bolts with high thermal conductivity.

[0092] The first temperature sensor may be provided on or inside the first heat transfer plate and sense the temperature of the heat transfer plate.The first temperature sensor may be embedded in the first heat transfer plate, for example, below an outer surface of the first heat transfer plate.

[0093] The first temperature sensor may be embedded in the first heat transfer plate at a distance between 1 and 18 mm from the semiconductor wafer supporting surface of the first heat transfer plate. For example, the first temperature sensor may be embedded in the first heat transfer plate at a distance between 2 and 12 mm from the semiconductor wafer supporting surface of the first heat transfer plate. This may mean that the first temperature sensor accurately measures the temperature of the semiconductor wafer supporting surface that contacts the semiconductor wafer.

[0094] The apparatus may be configured to load the semiconductor wafer onto the thermal transfer plate for a predetermined period of time sufficient to achieve thermal equilibrium between the semiconductor wafer and the thermal transfer plate.

[0095] Alternatively, the output of the first temperature sensor can be used to determine the time required to achieve thermal equilibrium between the semiconductor wafer and the heat transfer plate, and the time for positioning the semiconductor wafer on the heat transfer plate can be controlled accordingly. For example, the semiconductor wafer can be positioned on the heat transfer plate for exactly the determined time, or for the determined time plus a predetermined amount. This can reduce production time relative to positioning the semiconductor wafer on the heat transfer plate for the predetermined time.

[0096] The temperature of the semiconductor wafer is thus equalized to the temperature of the heat transfer plate. As the heat transfer plate is generally in thermal equilibrium with the measurement chamber, the temperature of the semiconductor wafer is generally equalized to the temperature of the measurement chamber due to the low heat load on the heat transfer plate.

[0097] The apparatus may further include a clamping mechanism, such as a vacuum clamping mechanism, for clamping the semiconductor wafer to the thermal transfer plate.

[0098] The apparatus may further comprise a sensing means / sensing device or unit for sensing an incomplete vacuum clamping of the semiconductor wafer to the thermal transfer plate. For example, the sensing means / device or unit may be a sensor for sensing an incomplete vacuum, for example.

[0099] If the semiconductor wafer is not properly clamped on the heat transfer plate, the semiconductor wafer may not be properly cooled at the heat transfer plate. In the case of measuring the temperature of the heat transfer plate when the semiconductor wafer leaves the heat transfer plate, the temperature of the semiconductor wafer may be unknown (because it is different from the temperature of the heat transfer plate), and the measurement error of subsequent measurements of the semiconductor wafer may be unpredictable. In this case, since the appropriate correction amount may be unpredictable, the device may generate an alarm and not correct the measurement of the semiconductor wafer.

[0100] Thus, the apparatus may include a control unit configured to control the operation of the apparatus based on the output of a sensor for sensing incomplete vacuum clamping of the semiconductor wafer to the thermal transfer plate. For example, the control unit may control the apparatus to provide an alert to a user of the apparatus. The control unit may be the same as or in addition to any of the previously mentioned control units.

[0101] The apparatus may comprise a conveying device / conveyor or a conveying apparatus configured to convey the semiconductor wafer from the first temperature changing unit directly to the measuring chamber. The term "directly" means without stopping at any additional unit, for example without stopping at any further temperature changing unit.

[0102] Of course, the present invention is not limited to providing only one or two temperature change components, but can provide any number of temperature change components for causing any number of temperature changes of the semiconductor wafer. Therefore, there may be multiple temperature change components for causing a series of multiple changes in the temperature of the semiconductor wafer.

[0103] According to a second aspect of the present invention, there is provided a semiconductor wafer quality metrology method, comprising:

[0104] before transferring the first semiconductor wafer into a measurement chamber for measuring the weight and / or mass of the semiconductor wafer, changing the temperature of the semiconductor wafer using a first temperature changing component; and

[0105] A first temperature is sensed, wherein the first temperature is:

[0106] the temperature of the first temperature changing component; or

[0107] The temperature of the semiconductor wafer when the semiconductor wafer is on the first temperature change member, or when the semiconductor wafer leaves the first temperature change member.

[0108] The semiconductor wafer quality metrology method according to the second aspect of the present invention may include any one of the optional features of the first aspect discussed above, or, where combinable, any combination of the optional features. For the sake of brevity, these optional features are not explicitly repeated here.

[0109] The method according to the second aspect of the present invention may additionally or alternatively include any one of the following optional features, or any combination of the following optional features where combinable.

[0110] The temperature of the first temperature change member may be measured when the semiconductor wafer is on the first temperature change member or when the semiconductor wafer is off the first temperature change member.

[0111] The method may include detecting:

[0112] a temperature change of the first temperature changing member caused by the semiconductor wafer; and / or

[0113] The maximum temperature of the first temperature change member caused by the semiconductor wafer.

[0114] The method may further include changing the temperature of the semiconductor wafer using a second temperature changing component before changing the temperature of the semiconductor wafer using the first temperature changing component.

[0115] The first temperature changing component may be used to passively cool the semiconductor wafer.

[0116] The second temperature changing component may be used to actively cool the semiconductor wafer.

[0117] However, as discussed above, the first or second temperature changing components may be used to actively or passively heat or cool the semiconductor wafer.

[0118] The method may include performing an operation based on the sensed first temperature and / or a change in the sensed first temperature. For example, performing an operation may include generating an alarm.

[0119] The method may include performing an operation based on a difference between the sensed first temperature and a second temperature (ie, the temperature of the measurement chamber).

[0120] The method may include, based on a difference between the first temperature and the second temperature:

[0121] Generate an alert; or

[0122] The quality measurement of the semiconductor wafer is corrected based on the difference between the first temperature and the second temperature and a predetermined relationship between the difference between the first temperature and the second temperature and the quality measurement error.

[0123] The predetermined relationship may be derived from a plurality of quality metrology measurements of one or more semiconductor wafers for different values ​​of the difference between the first temperature and the second temperature, and the known quality of the semiconductor wafers.

[0124] The temperature changing component may include a heat transfer plate thermally coupled to the measurement chamber.

[0125] The method may include vacuum clamping the semiconductor wafer onto a thermal transfer plate.

[0126] The method may further include sensing incomplete vacuum clamping of the semiconductor wafer to the thermal transfer plate.

[0127] The method may include performing an operation based on sensing an incomplete vacuum clamping of the semiconductor wafer to the thermal transfer plate. For example, performing an operation may include generating an alarm. BRIEF DESCRIPTION OF THE DRAWINGS

[0128] Embodiments of the present invention will now be discussed, by way of example only, with reference to the accompanying drawings, in which:

[0129] Figure 1 A semiconductor wafer quality metrology apparatus according to a first embodiment of the present invention is shown;

[0130] Figure 2 A semiconductor wafer quality metrology apparatus according to a second embodiment of the present invention is shown;

[0131] Figure 3 A semiconductor wafer quality metrology apparatus according to a third embodiment of the present invention is shown;

[0132] Figure 4 shows a schematic configuration of a passive heat transfer plate in some embodiments of the present invention;

[0133] Figure 5 It is shown by Figure 4 A graph of temperature changes measured by different temperature sensors in a heat transfer plate;

[0134] Figure 6is a graph showing quality measurement error relative to input wafer temperature offset;

[0135] Figure 7 is a graph showing an error in quality measurement relative to a difference between a temperature of a heat transfer plate and a temperature of a measurement chamber at a moment when a semiconductor wafer leaves the heat transfer plate;

[0136] Figure 8 is a graph showing a maximum temperature change of a heat transfer plate when a semiconductor wafer is on the heat transfer plate relative to a temperature difference between an incoming temperature of the semiconductor wafer and a temperature of a measurement chamber. DETAILED DESCRIPTION

[0137] Figure 1 A semiconductor wafer quality metrology apparatus according to a first embodiment of the present invention is shown.

[0138] The semiconductor wafer mass metrology device comprises a weighing balance 1 having a weighing pan 3 for receiving a semiconductor wafer. The weighing balance 1 is configured to provide a measurement output indicating the weight of the semiconductor wafer loaded on the weighing pan 3.

[0139] The weighing balance 1 is located in a weighing chamber 5 (measurement chamber) which forms a closed environment around the weighing balance 1, for example, to maintain a substantially uniform air density, air pressure and air temperature of the air around the weighing balance 1, as well as to prevent draught and provide electromagnetic shielding. The weighing chamber 5 has an opening (not shown), such as a slot of appropriate size on the side wall of the weighing chamber 5, to allow a semiconductor wafer to be transferred into the weighing chamber 5, for example by a robot, and to be positioned on the weighing pan 3. When not in use, the opening may be covered by an openable door or lid (not shown) to allow the weighing chamber 5 to be substantially closed or sealed when the weighing balance 1 is used to perform measurements.

[0140] A heat transfer plate 7 ("first temperature changing component") is positioned on top of the weighing chamber 5. The heat transfer plate 7 comprises a block of material (e.g., Al) having good thermal conductivity. The heat transfer plate also preferably has a high thermal mass so that its temperature changes slowly and little when heat is supplied to it, and has good lateral thermal conductivity so that the heat transfer plate maintains a substantially uniform temperature across its upper surface. In this embodiment, the heat transfer plate 7 is made of aluminum, but in other embodiments, any other material having good thermal conductivity may be used.

[0141] The heat transfer plate 7 is positioned directly on top of the weighing chamber 5 so that there is good thermal contact between the heat transfer plate 7 and the weighing chamber 5. The heat transfer plate 7 is in direct physical contact with the weighing chamber 5. The heat transfer plate 7 can be attached or fixed to the weighing chamber 5, for example, using one or more bolts (not shown) and / or a thermally conductive adhesive layer (not shown).

[0142] Due to the good thermal contact between the heat transfer plate 7 and the weighing chamber 5, the heat transfer plate 7 can usually be in thermal equilibrium with the weighing chamber 5, and thus can usually have a temperature that is substantially the same as the weighing chamber 5 (when the heat load on the heat transfer plate 7 is low). The weighing scale 1 can also be in thermal equilibrium with the weighing chamber 5, and thus can also have a temperature that is substantially the same as the weighing chamber 5. In this way, the heat transfer plate 7 can usually be in thermal equilibrium with the weighing scale 1, and thus can usually have a temperature that is substantially the same as the weighing scale 1 (when the heat load on the heat transfer plate 7 is low). However, as discussed below, when the heat load on the heat transfer plate 7 is high, the temperature of the heat transfer plate 7 may be different from the temperature of the weighing chamber 5.

[0143] In use, the semiconductor wafer to be measured is first positioned on the heat transfer plate 7 to reduce its temperature. A vacuum clamping mechanism is provided to vacuum clamp the semiconductor wafer to the heat transfer plate 7 so as to achieve good thermal contact between the heat transfer plate 7 and the semiconductor wafer, so that thermal equilibrium can be achieved in a short time (for example, the temperature difference between the heat transfer plate and the semiconductor wafer is less than 0.01°C within 20 seconds).

[0144] The semiconductor wafer is positioned on the heat transfer plate 7 for a predetermined period of time sufficient to achieve thermal equilibrium between the semiconductor wafer and the heat transfer plate 7. Typically, the heat transfer plate 7 and the weighing chamber 5 are in thermal equilibrium with each other (when the heat load on the heat transfer plate 7 is low), so that the semiconductor wafer reaches the same temperature as the temperature of the weighing chamber 5.

[0145] After the semiconductor wafer has been cooled by the heat transfer plate 7, it is transferred from the heat transfer plate 7 into the weighing chamber 5 and positioned on the weighing pan 3 of the weighing device 1 for measurement.

[0146] The semiconductor wafer is directly transferred from the heat transfer plate 7 into the weighing chamber 5, for example without staying at any intermediate temperature change unit. In particular, the device comprises a transfer mechanism (not shown) configured to transfer the semiconductor wafer directly from the heat transfer plate 7 into the weighing chamber 5.

[0147] Of course, in other embodiments, the heat transfer plate 7 may be located at a different position relative to the weighing chamber 5 .

[0148] like Figure 1 As shown, the heat transfer plate 7 has a first temperature sensor 8 embedded therein for measuring the temperature of the heat transfer plate 7. As discussed below, the first temperature sensor 8 can be used to measure the temperature of the heat transfer plate 7 when the semiconductor wafer is on the heat transfer plate 7, or at the moment when the semiconductor wafer leaves the heat transfer plate 7 after cooling. After the discussion of the second and third embodiments, the advantages of providing the first temperature sensor 8 are discussed below.

[0149] Other features of the first embodiment will be discussed later, following the discussion of the second and third embodiments.

[0150] Figure 2 A semiconductor wafer quality metrology apparatus according to a second embodiment of the present invention is shown.

[0151] Figure 2 Semiconductor wafer quality measurement device and Figure 1 The semiconductor wafer quality metrology apparatus of the present invention is different in that it further includes a second heat transfer plate 9 ("second temperature changing member"). A plurality of Peltier devices 11 are attached to the bottom side of the second heat transfer plate 9. Each Peltier device 11 has a heat sink 13 attached to its bottom side. An air flow 15 may be provided in an area 17 below the bottom side of the second heat transfer plate 9 to remove heat from the Peltier devices 11 and the heat sink 13. Of course, the configuration of the air flow may be different from that of the embodiment of the present invention. Figure 2 For example, air can be blown out from the bottom of area 17 by a fan.

[0152] exist Figure 2 In the embodiment, the second heat transfer plate 9 is shown as being positioned on the right side of the weighing chamber 5. However, in other embodiments, the second heat transfer plate 9 can be positioned differently, such as on a different side of the weighing chamber 5, above or below, or above the weighing chamber 5. Figure 2 As shown closer or further away from the weighing chamber 5. In other embodiments, the second heat transfer plate 9 can be attached or connected to the heat transfer plate 7 directly or indirectly.

[0153] In use, a wafer conveyor, such as an end effector of a robot arm of an EFEM, is used to remove a semiconductor wafer from a FOUP (not shown) or alternatively from another processing device (not shown), and to transfer the semiconductor wafer to and position the semiconductor wafer on the second heat transfer plate 9. When the semiconductor wafer is removed from the FOUP (or another processing device), it may have a temperature of about 70° C. For example, the semiconductor wafer may have been processed at a processing station of a semiconductor equipment production line, which may have heated the semiconductor wafer to a temperature of 400 to 500° C. before the semiconductor wafer was loaded into the FOUP.

[0154] When the semiconductor wafer is positioned on the second heat transfer plate 9, heat is conducted from the semiconductor wafer to the second heat transfer plate 9, thereby reducing the temperature of the semiconductor wafer. The semiconductor wafer and the second heat transfer plate 9 can achieve thermal equilibrium (e.g., so that they have substantially the same temperature), depending on how long the semiconductor wafer is positioned on the second heat transfer plate 9. The heat transfer from the semiconductor wafer to the second heat transfer plate 9 will act to increase the temperature of the second heat transfer plate 9. In that case, the thermal equilibrium temperature of the semiconductor wafer and the second heat transfer plate 9 may be different from the desired temperature of the semiconductor wafer. In order to prevent the temperature of the second heat transfer plate 9 from increasing due to the heat load from the semiconductor wafer, the second heat transfer plate 9 is operable to actively dissipate the heat load removed from the semiconductor wafer. In particular, the Peltier device 11 is operated to actively remove heat from the second heat transfer plate 9. In other words, power is supplied to the Peltier device 11 so that it acts as an active heat pump that transfers heat from its upper surface in contact with the second heat transfer plate 9 to its lower surface to which the heat sink 13 is attached.

[0155] An air flow 15 is provided in a region 17 below the second heat transfer plate 9, in which region the Peltier device 11 and the heat sink 13 are located, in order to remove heat from the Peltier device 11 and the heat sink 13. Thus, the heat removed from the semiconductor wafer by the second heat transfer plate 9 is conveyed by the air flow 15 and dissipated from the weighing chamber 5 of the weighing device, so that this heat has no influence on the temperature of the weighing device. The air flow 15 can be generated, for example, by one or more fans located in the region 17 or at its edge. In other words, heat is actively dissipated from the second heat transfer plate 9.

[0156] As described above, actively dissipating heat from the second heat transfer plate 9 will prevent heat from accumulating in the second heat transfer plate 9, which would cause an increase in the temperature of the second heat transfer plate 9. In this embodiment, the heat removed from the semiconductor wafer is effectively / efficiently handled by dissipating through the second heat transfer plate 9. This can make it possible to more accurately / precisely control the temperature of the semiconductor wafer by using the second heat transfer plate 9.

[0157] The second heat transfer plate 9 is operated to remove a majority of the heat load from the semiconductor wafer so that the temperature of the semiconductor wafer is reduced to a temperature close to the desired temperature of the semiconductor wafer when it is positioned on the weighing pan 3. The second heat transfer plate 9 may remove more than 90%, or more than 95%, or more than 99% of the heat required to reduce the temperature of the semiconductor wafer to the desired temperature. In other words, the second heat transfer plate 9 may cause more than 90%, more than 95%, or more than 99% of the temperature change required to reduce the temperature of the semiconductor wafer from its initial temperature to the desired temperature when it is positioned on the weighing pan 3.

[0158] Generally, it is desirable to substantially match the temperature of the semiconductor wafer to the temperature of the weighing chamber 5, so that when the semiconductor wafer is loaded onto the weighing pan 3, there is substantially no temperature difference between the semiconductor wafer and the weighing chamber 5 (and therefore, substantially no temperature difference between the semiconductor wafer and the weighing scale 1). In this embodiment, the second heat transfer plate 9 can cool the semiconductor wafer to within ±1°C of the temperature of the weighing chamber 5. For example, in the case where the weighing chamber has a temperature of 20°C, the second heat transfer plate 9 can cool the semiconductor wafer to a temperature of (20±1)°C. However, in other embodiments, the amount of cooling provided by the second heat transfer plate 9 can be different from this, as long as the second heat transfer plate 9 provides at least more than 50%, and preferably more than 80%, of the desired temperature change of the semiconductor wafer.

[0159] Once the semiconductor wafer is cooled to a temperature close to the desired temperature using the second heat transfer plate 9, the semiconductor wafer is transferred to the first heat transfer plate 7 using a wafer conveyor. Preferably, the wafer conveyor is used to transfer the semiconductor wafer to the first heat transfer plate 7, which is different from the wafer conveyor used to transfer the semiconductor wafer to the second heat transfer plate 9. In this embodiment, two different end effectors of the robot arm of the EFEM are used to perform two different transfer steps. The end effector that transfers the semiconductor wafer to the second heat transfer plate 9 can be heated by the semiconductor wafer 9. If the same end effector is used to transfer the cooled semiconductor wafer from the second heat transfer plate 9 to the heat transfer plate 7, it can transfer heat back to the semiconductor wafer, thereby changing its temperature. This problem can be avoided by using a different end effector for the second transfer step. The end effector can be a surface on which a semiconductor wafer can be supported, such as a support member positioned below the semiconductor wafer. The end effector can have a specific device / equipment / unit that is used to grip or clamp the semiconductor wafer in place when the semiconductor wafer is transferred by the end effector.

[0160] The end effector may be configured to minimize or reduce the thermal contact area between the end effector and the semiconductor wafer in order to minimize heat transfer between the end effector and the semiconductor wafer. For example, the end effector may contact the semiconductor wafer only at the edge of the semiconductor wafer. Alternatively or additionally, the end effector may be made of a material with poor thermal conductivity (i.e., a thermal insulator) to minimize heat transfer between the end effector and the semiconductor wafer.

[0161] As discussed above, when the semiconductor wafer is positioned on the thermal transfer plate 7, there is good thermal contact between the semiconductor wafer and the thermal transfer plate 7. Therefore, the semiconductor wafer is cooled by conducting heat from the semiconductor wafer to the thermal transfer plate 7. The semiconductor wafer and the thermal transfer plate 7 may be substantially in thermal equilibrium so that they have substantially the same temperature, depending on the length of time the semiconductor wafer is positioned on the thermal transfer plate 7. In this embodiment, the semiconductor wafer may be positioned on the thermal transfer plate 7 for a period of time sufficient to achieve thermal equilibrium, for example, 60 seconds.

[0162] The semiconductor wafer has had most of its heat load removed by the second heat transfer plate 9 before being positioned on the heat transfer plate 7. Therefore, during temperature equalization, the heat load on the heat transfer plate 7 is very low, and during temperature equalization (when the heat load on the heat transfer plate 7 is low), the temperature of the heat transfer plate 7 and the weighing chamber 5 (which has a higher thermal mass) can be kept substantially constant. In addition, relatively little heat must be exchanged to bring the semiconductor wafer into thermal equilibrium with the heat transfer plate 7. However, in the case of measuring many semiconductor wafers, the heat load on the heat transfer plate may still be sufficient to cause a small deviation between the temperature of the heat transfer plate 7 and the temperature of the weighing chamber 5.

[0163] Therefore, with this embodiment, because the steps of removing most of the heat load from the semiconductor wafer and equalizing the temperature of the semiconductor wafer have been separated, it is possible to more precisely / accurately equalize the temperature of the semiconductor wafer to a desired temperature. For example, with this embodiment, it is possible to match the temperature of the semiconductor wafer to the temperature of the weighing chamber 5 to an accuracy of less than 0.1°C, or an accuracy of less than 0.01°C, or even an accuracy on the order of 0.001°C.

[0164] When the temperature of the semiconductor wafer is substantially equalized with the temperature of the thermal transfer plate 7 (e.g., when the semiconductor wafer has been on the thermal transfer plate 7 for a predetermined period of time), the semiconductor wafer is transferred from the thermal transfer plate 7 to the weighing pan 3 by the wafer conveyor. The weighing scale 1 is then used to provide a measurement output indicative of the weight of the semiconductor wafer.

[0165] As with the first embodiment, a first temperature sensor 8 is embedded in the heat transfer plate 7 to measure the temperature of the heat transfer plate 7. Advantages of providing such a first temperature sensor 8 are discussed below after discussing the third embodiment.

[0166] Additional features of the second embodiment of the present invention are discussed below, following the discussion of the third embodiment.

[0167] Figure 3 A semiconductor wafer quality metrology apparatus according to a third embodiment of the present invention is shown.

[0168] The main difference between the second and third embodiments is the positioning of the second heat transfer plate 9. In the third embodiment, the second heat transfer plate 9 is stacked above the heat transfer plate 7. A thermal gap 19, such as an air gap or a layer of insulating material, is positioned between the heat transfer plate 7 and the second heat transfer plate 9, thereby substantially thermally insulating the heat transfer plates 7, 9 from each other so that substantially no heat can pass between the heat transfer plates 7, 9.

[0169] The floor space in semiconductor device production facilities is usually limited. Therefore, in order to save floor space, the second heat transfer plate 9 is stacked above the heat transfer plate 7 (i.e., similar to Figure 3 The arrangement shown) may be advantageous. In this arrangement, the semiconductor wafer is conveyed vertically between the heat transfer plates 7, 9 and the weighing pan 3.

[0170] Other features of the first to third embodiments of the present invention are discussed below.

[0171] Figures 1 to 3 The arrangement shown is merely an exemplary arrangement, and other configurations of measurement chambers and temperature changing components are possible in the present invention and will be apparent to those skilled in the art in light of the above disclosure.

[0172] Furthermore, in other embodiments, the heat transfer plates 7, 9 may be replaced by other types of temperature changing components that actively or passively heat or cool the semiconductor wafer.

[0173] As discussed above, the inventors have recognized that in any of the embodiments discussed above, as well as in other possible embodiments, when measuring a series of semiconductor wafers, the temperature of the thermal transfer plate 7 may deviate from the temperature of the weigh chamber 5 over time, causing the temperatures to be different. This temperature difference may lead to subsequent errors in the quality measurement of the semiconductor wafers (as discussed in more detail below).

[0174] Therefore, in an embodiment of the present invention, a temperature sensor is provided to measure the temperature of the heat transfer plate 7 or the temperature of the semiconductor wafer when the semiconductor wafer is on the first temperature change member or when the semiconductor wafer leaves the first temperature change member.

[0175] exist Figures 1 to 3 , the temperature sensor 8 is shown as being embedded in the thermal transfer plate 7 so as to measure the temperature of the thermal transfer plate 7. However, the temperature sensor may also be provided on the surface of the thermal transfer plate 7. In another embodiment, the temperature sensor may be a non-contact temperature sensor that is not in direct contact with the thermal transfer plate 7, such as an IR-based temperature sensor.

[0176] Figure 4 A schematic diagram showing an example of a heat transfer plate 7 according to an exemplary embodiment of the present invention is shown. Figure 4 In FIG. 1 , many different temperature sensors have been provided in various different positions on the heat transfer plate 7 to illustrate the measurement of the temperature of the heat transfer plate 7. Specifically, temperature sensors RTD#5 to RTD#9 have been provided at different depths and heights inside the heat transfer plate 7. In practice, only a single temperature sensor may be provided.

[0177] exist Figure 4 In the example, multiple temperature sensors are provided to illustrate the effect of the location of the temperature sensors on the temperature measurement of the temperature sensors. However, in practice, only a single temperature sensor will be provided, or only a small number of temperature sensors will be provided. For example, a single temperature sensor may be provided as close to the wafer support surface of the semiconductor wafer as practical.

[0178] Figure 5 FIG. 2 shows the change in temperature over time measured by temperature sensors RTD#5 to RTD#9 as a series of hot semiconductor wafers are sequentially loaded onto the heat transfer plate 7 before measurement. Figure 5 As shown, due to the high heat load on the heat transfer plate 7, the temperature of the heat transfer plate 7 increases over time as a series of hot semiconductor wafers are loaded onto the heat transfer plate 7.

[0179] This rapid increase in the temperature of the heat transfer plate 7 may mean that the temperature of the heat transfer plate 7 deviates from the temperature of the measurement chamber, leading to subsequent errors in the mass measurement discussed above. Figure 1 In the implementation scheme, this deviation and subsequent error are Figure 2 and Figure 3 will be larger than the implementation scheme due to the Figure 1 The heat load on the heat transfer plate 7 is greater in the embodiment of FIG.

[0180] also, Figure 5 The curve graph in shows that the temperature of the heat transfer plate 7 changes as the semiconductor wafer is positioned on the heat transfer plate 7, and in particular, when the semiconductor wafer is on the heat transfer plate 7, the temperature of the heat transfer plate 7 peaks or surges, which is caused by the temperature difference between the semiconductor wafer and the heat transfer plate 7.

[0181] In some embodiments of the present invention, this peak / surge can be detected or measured for each semiconductor wafer, and this information can be used to calculate the temperature of the semiconductor wafer when it reaches the thermal transfer plate 7. As discussed below, the operation of the device or individual devices can then be controlled based on the calculated temperature of the incoming wafer.

[0182] Figure 6is a graph of experimental data showing the error in subsequent quality measurement for a semiconductor wafer relative to the difference between the initial temperature of the semiconductor wafer when it is placed on the thermal transfer plate 7 and the temperature of the measurement chamber at the time of sampling.

[0183] Depend on Figure 6 It is known that when the difference between the temperature of the semiconductor wafer when it is placed on the heat transfer plate 7 and the temperature of the measurement chamber at the time of sampling is large, this can cause significant errors in the subsequent quality measurement. This is because the large heat load on the heat transfer plate 7 causes the temperature of the heat transfer plate 7 to deviate from the temperature of the measurement chamber over time.

[0184] Figure 6 The different dashed lines in represent data from different semiconductor wafers. The data are obtained by heating or cooling different semiconductor wafers to different temperature ranges relative to the temperature of the measurement chamber before passing the semiconductor wafer through the heat transfer plate 7 before measurement in the measurement chamber.

[0185] Figure 7 is with Figure 6 A graph of experimental data for the same semiconductor wafer showing the relationship between mass error in subsequent measurements and the temperature difference between the heat transfer plate 7 and the weighing chamber 5 at the moment the semiconductor wafer leaves the heat transfer plate 7 .

[0186] from Figure 7 It can be seen that there is a correlation between the mass error in the subsequent measurement and the temperature difference between the heat transfer plate 7 and the weighing chamber 5 at the moment when the semiconductor wafer leaves the heat transfer plate 7 .

[0187] In particular, there is a linear (straight line) relationship.

[0188] Therefore, if this correlation is known (for example from previously performed experiments), it is possible to determine errors in subsequent quality measurements performed on the semiconductor wafer based on the temperature difference between the heat transfer plate 7 and the weighing chamber 5 at the moment when the semiconductor wafer leaves the heat transfer plate 7.

[0189] Figure 8 Graph 1 is a graph showing the maximum temperature change of the heat transfer plate 7 when the semiconductor wafer is on the heat transfer plate 7 relative to the temperature difference between the entry temperature of the semiconductor wafer and the temperature of the measurement chamber. Figure 8 As shown in FIG. 1 , when the semiconductor wafer is on the heat transfer plate 7, the maximum temperature change of the heat transfer plate 7 is correlated with the temperature difference between the inlet temperature of the semiconductor wafer and the temperature of the measurement chamber (the line in the graph is a straight line). Therefore, in an embodiment of the present invention, when the semiconductor wafer is on the heat transfer plate 7, the maximum temperature change of the heat transfer plate 7 is detected or measured, and this information is used to calculate the maximum temperature of the heat transfer plate 7 by using, for example, Figure 8The predetermined relationship shown determines the temperature difference between the incoming temperature of the semiconductor wafer and the temperature of the measurement chamber.

[0190] Although the temperature of the heat transfer plate 7 is measured in the above examples, in other embodiments the temperature of the semiconductor wafer itself may be measured directly.

[0191] In some embodiments of the present invention, a second temperature sensor is provided to measure the temperature of the weighing chamber 5. Alternatively, the temperature of the weighing chamber 5 may be accurately controlled to a specific temperature, so that a second temperature sensor is unnecessary.

[0192] In some embodiments, the device is provided with a control unit that compares the measured temperature of the thermal transfer plate 7 (or semiconductor wafer) with the measured or known temperature of the weighing chamber 5. For example, the control unit may calculate the difference between these temperatures by subtraction.

[0193] Based on the comparison, the control unit may then control the operation of the apparatus or individual devices or apparatuses.

[0194] In a first example, the control unit may be configured to provide an alarm if the temperature of the heat transfer plate 7 differs from the temperature of the weighing chamber 5, or if the temperatures differ by more than a predetermined amount.

[0195] For example, the device may have a display on which a visible alarm is displayed. Alternatively, the device may have a speaker through which an audible alarm is provided.

[0196] This alarm warns the operator of the equipment that the mass measurement may be erroneous.

[0197] In a second example, the control unit may be configured to correct the mass measurement of the semiconductor wafer based on the comparison. In particular, the control unit may store a predetermined relationship between the mass measurement error and the temperature difference between the temperature of the heat transfer plate 7 (or the semiconductor wafer) and the temperature of the weighing chamber 5 in the memory. Therefore, by inputting the temperature difference between the temperature of the heat transfer plate 7 (or the semiconductor wafer) and the temperature of the weighing chamber 5 at the moment when the semiconductor wafer leaves the heat transfer plate 7 into a predetermined relationship, the expected mass measurement error can be output and then used to correct the mass measurement for the semiconductor wafer.

[0198] Can be based on Figure 7 The predetermined relationship is determined by experimental data shown in FIG. 1 , which is obtained by performing a plurality of mass measurements on semiconductor wafers having different differences between the temperature of the heat transfer plate 7 (or the semiconductor wafer) and the temperature of the weighing chamber 5 at the moment when the semiconductor wafer leaves the heat transfer plate 7. For example, the predetermined relationship may be Figure 7 An equation for the linear relationship in , or alternatively, a lookup table for other specific relationships.

[0199] Correcting the quality measurements in this way means that hotter wafers can be transferred directly to the heat transfer plate 7 than was previously possible, since errors caused by large temperature excursions can be corrected. This means that in some embodiments the apparatus may not need to provide Figure 2 and Figure 3 The active heat transfer plate 9 is an expensive component, so if it can be omitted, the device will be more cost-effective while still maintaining appropriate accuracy due to the subsequent correction of measurement errors.

[0200] To achieve the highest accuracy, Figure 2 and Figure 3 It is shown that a second heat transfer plate 9 is additionally provided.

[0201] In an alternative embodiment where a second heat transfer plate 9 is provided, the determined difference between the temperature of the heat transfer plate 7 (or semiconductor wafer) and the weigh chamber 5 at the moment the semiconductor wafer leaves the heat transfer plate 7 can be used to change the operation of the second heat transfer plate 9. For example, in the event that it is determined that the temperature of the second heat transfer plate 9 is greater than the temperature of the weigh chamber 5, the amount of cooling provided by the active heat transfer plate 9 can be increased so as to reduce the downstream temperature difference between the temperature of the heat transfer plate 7 (or semiconductor wafer) and the weigh chamber 5.

[0202] Additionally, or alternatively, in embodiments of the present invention, the maximum temperature change of the heat transfer plate 7 when the semiconductor wafer is thereon may be measured, and this information may instead be used to control the operation of the second heat transfer plate, for example, the amount of cooling provided by the active heat transfer plate 9 may be increased in order to reduce subsequent temperature changes of the heat transfer plate 7 when a semiconductor wafer is placed thereon.

[0203] Of course, the options discussed above are not mutually exclusive and can be combined in any order. For example, the control unit can be configured to correct the quality measurement of the semiconductor wafer and control the operation of the second heat transfer plate, or provide an alarm and control the operation of the second heat transfer plate, or provide an alarm and correct the quality measurement for the semiconductor wafer, etc.

[0204] As described above, the apparatus may include a vacuum clamping mechanism to vacuum clamp the semiconductor wafer to the heat transfer plate 7 to ensure thermal contact. However, a severely warped wafer will not be properly clamped to the heat transfer plate 7 and therefore will not be able to reach thermal equilibrium with the heat transfer plate 7 within a specified time.

[0205] Therefore, a sensor or other detection device / apparatus / unit may be provided to detect an incomplete vacuum clamping of the semiconductor wafer to the thermal transfer plate 7. In the event that an incomplete vacuum clamping is detected and the temperature of the thermal transfer plate 7 is being measured, then the error in the quality measurement cannot be determined since the temperature of the semiconductor wafer is unknown. Therefore, when an incomplete vacuum clamping is detected, the device may be configured not to correct the quality measurement but to issue an alarm.

[0206] The apparatus may be configured to perform an action, such as generating an alarm, upon detection of incomplete vacuum grip.

[0207] Of course, in other embodiments of the present invention, other types of temperature changing components may be provided in place of the heat transfer plates of the embodiments discussed above.

Claims

1. A semiconductor wafer quality measurement device, comprising: a measuring chamber for measuring the weight and / or mass of a semiconductor wafer; a first temperature changing member for changing the temperature of the semiconductor wafer before transferring the semiconductor wafer to the measurement chamber; as well as a first temperature sensor for sensing a first temperature, wherein the first temperature is a temperature of the first temperature changing component; The first temperature changing component is used to passively cool the semiconductor wafer or passively heat the semiconductor wafer.

2. The semiconductor wafer quality measurement device according to claim 1, wherein: The first temperature changing component is used to passively cool the semiconductor wafer.

3. The semiconductor wafer quality measurement device according to claim 1 or claim 2, wherein: The apparatus further comprises a second temperature changing component for actively cooling the semiconductor wafer.

4. The semiconductor wafer quality measurement device according to claim 1, wherein: The temperature of the first temperature change member is measured when the semiconductor wafer is on the first temperature change member or when the semiconductor wafer is away from the first temperature change member.

5. The semiconductor wafer quality measurement device according to claim 1, wherein: The first temperature sensor is configured to detect: a temperature change of the first temperature changing member caused by the semiconductor wafer; and / or The maximum temperature of the first temperature change member caused by the semiconductor wafer.

6. The semiconductor wafer quality measurement device according to claim 1, wherein: The apparatus further comprises a control unit configured to control the operation of the apparatus based on: the first sensed temperature; and / or a sensed change in the first temperature; and / or The difference between the sensed first temperature and a second temperature being the temperature of the measurement chamber.

7. The semiconductor wafer quality measurement device according to claim 6, wherein: The control unit is configured to: Generate alerts; and / or Based on the difference between the first temperature and the second temperature and a predetermined relationship between the difference between the first temperature and the second temperature and a quality measurement error, a quality measurement for the semiconductor wafer is corrected.

8. The semiconductor wafer quality measurement device according to claim 7, wherein: The predetermined relationship is derived from a plurality of quality metrology measurements of one or more semiconductor wafers for different differences between the first temperature and the second temperature and a known quality of the semiconductor wafers.

9. The semiconductor wafer quality metrology device according to any one of the preceding claims 1-2 and 4-8, wherein: The first temperature changing component includes a first heat transfer plate thermally coupled to the measurement chamber.

10. The semiconductor wafer quality measurement device according to claim 9, wherein: The apparatus is configured to load the semiconductor wafer onto the first thermal transfer plate for a predetermined period of time sufficient to achieve thermal equilibrium between the semiconductor wafer and the first thermal transfer plate.

11. The semiconductor wafer quality metrology device according to claim 9, wherein: The apparatus includes a vacuum chuck for vacuum clamping the semiconductor wafer onto the first thermal transfer plate; The apparatus includes a sensor for sensing an incomplete vacuum clamping of the semiconductor wafer onto the first thermal transfer plate; as well as The apparatus includes a control unit configured to control operation of the apparatus based on an output of a sensor for sensing incomplete vacuum clamping of the semiconductor wafer onto the first thermal transfer plate.

12. The semiconductor wafer quality metrology device according to claim 1, wherein: The first temperature changing member comprises a first heat transfer plate; and The first temperature sensor is embedded in the first heat transfer plate.

13. The semiconductor wafer quality measurement device according to claim 12, wherein: The first temperature sensor is embedded in the first heat transfer plate at a distance of 1 to 18 mm from a semiconductor wafer supporting surface of the first heat transfer plate.

14. The semiconductor wafer quality measurement device according to claim 12, wherein: The first temperature sensor is embedded in the first heat transfer plate at a distance of 2 to 12 mm from the semiconductor wafer supporting surface of the first heat transfer plate.

15. A semiconductor wafer quality measurement method, comprising: before transferring the semiconductor wafer into a measurement chamber for measuring the weight and / or mass of the semiconductor wafer, changing the temperature of the semiconductor wafer using a first temperature changing component; and A first temperature is sensed, wherein the first temperature is a temperature of the first temperature change component, wherein the first temperature change component is used to passively cool the semiconductor wafer or passively heat the semiconductor wafer.

16. The semiconductor wafer quality metrology method according to claim 15, wherein: The temperature of the first temperature change member is measured when the semiconductor wafer is on the first temperature change member or when the semiconductor wafer is away from the first temperature change member.

17. The semiconductor wafer quality metrology method according to claim 15 or claim 16, wherein: The method comprises detecting: a temperature change of the first temperature changing member caused by the semiconductor wafer; and / or The maximum temperature of the first temperature change member caused by the semiconductor wafer.

18. The semiconductor wafer quality metrology method according to claim 15, wherein: The method further includes changing the temperature of the semiconductor wafer using a second temperature changing component before changing the temperature of the semiconductor wafer using the first temperature changing component; The first temperature changing component is used to passively cool the semiconductor wafer; and The second temperature changing component is used to actively cool the semiconductor wafer.

19. The semiconductor wafer quality metrology method according to claim 15, wherein: The method further includes performing operations based on: the first sensed temperature; and / or a sensed change in the first temperature; and / or The difference between the sensed first temperature and a second temperature being the temperature of the measurement chamber.

20. The semiconductor wafer quality metrology method according to claim 19, wherein: Performing the operations includes: Generate an alert; or Based on the difference between the first temperature and the second temperature and a predetermined relationship between the difference between the first temperature and the second temperature and a quality measurement error, a quality measurement for the semiconductor wafer is corrected.

21. The semiconductor wafer quality metrology method according to claim 20, wherein: The predetermined relationship is derived from a plurality of quality metrology measurements of one or more semiconductor wafers for different differences between the first temperature and the second temperature and a known quality of the semiconductor wafers.

22. The semiconductor wafer quality metrology method according to any one of claims 15 to 16 and 18 to 21, wherein: The first temperature changing component includes a heat transfer plate thermally coupled to the measurement chamber.

23. The semiconductor wafer quality metrology method according to claim 22, wherein: The method includes vacuum clamping the semiconductor wafer onto the thermal transfer plate; sensing an incomplete vacuum clamping of the semiconductor wafer onto the thermal transfer plate; as well as An operation is performed based on sensing the incomplete vacuum clamping of the semiconductor wafer to the thermal transfer plate.

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