A temperature compensation method for semiconductor equipment replacement pyrometer scenario

Abstract

The present invention provides a temperature compensation method for a semiconductor device replacement pyrometer scenario, by verifying the accuracy of a target temperature prediction algorithm before replacing the pyrometer, after the pyrometer is replaced, a standard test process is run through the semiconductor device, and the measured temperature of the corresponding position of the wafer is measured by a second pyrometer set at each measurement point, and the heating power of the corresponding heating element under different measurement temperatures is detected at the same time, and based on the target temperature prediction algorithm, the target temperature of the corresponding position of the wafer is predicted according to the heating power; then, based on each measurement temperature and its corresponding target temperature, the reading of the corresponding second pyrometer is compensated to obtain the final measurement value of the second pyrometer. The present invention can compensate the reading of the second pyrometer according to the target temperature, thereby improving the accuracy of the final measurement value of the second pyrometer.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and in particular to a temperature compensation method for a scenario where a pyrometer of a semiconductor device is replaced. Background Art

[0002] In the semiconductor manufacturing process, the rapid thermal processing (RTP) process is used to heat the wafer quickly and uniformly. It is usually used in the activation and diffusion of dopants after ion implantation, the annealing after the formation of metal silicide, and the annealing of the gate oxide layer.

[0003] In the rapid thermal processing process, a single wafer is placed in a closed reaction chamber and heated using a specific heat source and a preset temperature program to quickly reach the desired temperature. In terms of temperature control, the temperature range of the rapid thermal processing process is usually between 180°C and 1200°C, and the temperature deviation is usually required to be less than 1°C. A pyrometer is generally used to measure the process temperature.

[0004] In actual applications, rapid thermal processing equipment is usually equipped with a calibrated and temperature-accurate verified standard pyrometer to measure the wafer temperature, so that the temperature of the rapid thermal processing process can be controlled according to the measured value. However, during use, in some scenarios (such as when the standard pyrometer shipped from the factory is aged, contaminated or damaged and cannot be purchased), it may be necessary to replace the standard pyrometer with a pyrometer of another brand or model.

[0005] Therefore, after the pyrometer is replaced, how to ensure that there is no deviation in the temperature measurement of the device is an urgent problem to be solved by the present invention. Summary of the invention

[0006] In order to avoid the problem of temperature measurement deviation after a pyrometer is replaced, the present invention provides a temperature compensation method for a scenario in which a pyrometer is replaced in a semiconductor device.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A temperature compensation method for a semiconductor device in which a pyrometer is replaced, wherein the device comprises a plurality of heating elements and a plurality of measuring points are distributed in the device, and the method comprises:

[0009] A preset standard test process is run in the semiconductor device to heat the wafer, and the following steps are performed for each measuring point during the heating process: a standard temperature of a corresponding position of the wafer is measured by a first pyrometer set at the measuring point, and the heating power of the heating element corresponding to the measuring point position at different standard temperatures is detected, and a preset temperature prediction algorithm is used to predict the predicted temperature of the corresponding position of the wafer according to the heating power, and when the predicted temperature corresponding to each measuring point matches the standard temperature, the temperature prediction algorithm is determined to be a target temperature prediction algorithm;

[0010] After replacing the first pyrometer set at each measuring point with a second pyrometer, the standard test process is run in the semiconductor device to heat the wafer, and the following steps are performed for each measuring point during the heating process: measuring the measured temperature of the corresponding position of the wafer by the second pyrometer set at the measuring point, and detecting the heating power of the heating element corresponding to the position of the measuring point at different measuring temperatures, and predicting the target temperature of the corresponding position of the wafer by using the target temperature prediction algorithm according to the heating power;

[0011] Based on the target temperature corresponding to each of the measured temperatures, the corresponding relationship between the reading of the corresponding second pyrometer and the target temperature is fitted to compensate the reading of the corresponding second pyrometer based on the corresponding relationship to obtain a final measurement value of the second pyrometer.

[0012] Further, the predicted temperature of the corresponding position of the wafer is predicted by using a preset temperature prediction algorithm, including:

[0013] Based on the temperature prediction algorithm, the amount of heat absorbed by the corresponding position of the wafer under the corresponding heating power is predicted, and the predicted temperature of the corresponding position of the wafer is calculated according to the amount of heat absorbed.

[0014] Further, compensating the reading of the corresponding second pyrometer includes:

[0015] Based on the corresponding relationship between the reading of the second pyrometer and the target temperature, the target temperature corresponding to the reading of the second pyrometer is obtained as the final measurement value of the second pyrometer.

[0016] Furthermore, the heating element is a heating lamp, and the heating power of the heating lamp is provided by a heating control device.

[0017] Furthermore, the heating control device is an IGBT or a SCR.

[0018] Furthermore, the plurality of heating elements form a plurality of heating zones centered on the central axis of the wafer, and the heating power of each heating zone can be controlled individually.

[0019] Furthermore, the plurality of measuring points are distributed on concentric circles centered on the central axis of the wafer, and the concentric circles correspond to the heating areas one by one.

[0020] Furthermore, the method further comprises: controlling the heating power of the corresponding heating area based on the final measurement value of each of the second pyrometers.

[0021] Furthermore, the semiconductor device is a rapid thermal processing device.

[0022] Furthermore, the first pyrometer and the second pyrometer are pyrometers of different brands or models.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects:

[0024] The present invention verifies the accuracy of the target temperature prediction algorithm before replacing the pyrometer. After the pyrometer is replaced, the standard test process is run through the semiconductor device to heat the wafer, and the measured temperature of the corresponding position of the wafer is measured by the second pyrometer set at each measuring point during the heating process, and the heating power of the corresponding heating element at different measuring temperatures is detected at the same time, and based on the target temperature prediction algorithm, the target temperature of the corresponding position of the wafer is predicted according to the heating power; then, based on each measured temperature and its corresponding target temperature, the reading of the corresponding second pyrometer is compensated to obtain the final measurement value of the second pyrometer. Since the accuracy of the target temperature prediction algorithm is verified, the target temperature of the corresponding position of the wafer predicted based on the target temperature prediction algorithm is the standard temperature, and thus the reading of the second pyrometer is compensated according to the target temperature, which can improve the accuracy of the final measurement value of the second pyrometer, and then can achieve accurate control of the process temperature, which is beneficial to ensure the yield of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the distribution of heating elements in the present invention;

[0026] Figure 2 Schematic diagram of the distribution of measurement points in the present invention;

[0027] Figure 3 The present invention is a flow chart of a temperature compensation method for a scenario where a pyrometer is replaced in a semiconductor device. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] The terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure. The singular forms "a", "the" and "the" used in the present disclosure and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0030] In actual applications, rapid thermal processing equipment is usually equipped with a calibrated and temperature-accurate verified standard pyrometer to measure the wafer temperature when it leaves the factory, so that the temperature of the rapid thermal processing process can be controlled according to the measured value. However, during use, in some scenarios, it may be necessary to replace the standard pyrometer with a pyrometer of another brand or model. In order to ensure the accuracy of temperature control, it is necessary to ensure that the reading of the pyrometer after replacement is consistent with the reading of the pyrometer before replacement.

[0031] Based on this, the present invention provides a temperature compensation method for a semiconductor device replacing a pyrometer, wherein the semiconductor device includes but is not limited to a rapid thermal processing device.

[0032] like Figure 1 As shown, the semiconductor device of the present invention uses a plurality of heating elements 10 (such as heating lamps) to perform full radiation heating on the wafer. Preferably, these heating elements 10 form a plurality of heating areas centered on the central axis of the wafer. For example, Figure 1 Specifically, 7 heating zones can be formed, which are denoted as Z1, Z2, Z3, Z4, Z5, Z6 and Z7 from the center to the edge, and the heating power of each heating zone can be controlled separately. Among them, Z1 is a circular heating zone, and Z2~ Z7 are annular heating zones adjacent to each other. In a specific embodiment, when the processed wafer is a 12-inch wafer, the radius of Z1 is 12mm, and the outer diameters of Z2~ Z7 are 25.4mm, 50.8mm, 76.2mm, 101.6mm, 127mm and 140mm respectively. It should be understood that the present invention does not limit the size of the heating zone, and the size of each heating zone can be adjusted according to specific process conditions.

[0033] In the present invention, in order to achieve accurate temperature control of the rapid thermal processing process, a plurality of measuring points are provided in the semiconductor device for the pyrometer to perform temperature measurement at the corresponding measuring points. Preferably, the plurality of measuring points are distributed on concentric circles centered on the central axis of the wafer, and the concentric circles correspond to the heating areas one by one. Figure 2 As shown in the figure, the concentric circles are marked as T1, T2, T3, T4, T5, T6 and T7 from the center to the edge. When the processed wafer is a 12-inch wafer, the radii of T1~T7 are 12mm, 25.4mm, 50.8mm, 76.2mm, 101.6mm, 127mm and 140mm, which correspond to the outer diameter of the heating area one by one.

[0034] In an operative manner, the heating element 10 in each heating area is individually controlled by a heating control device, and the output current and output voltage of the heating control device determine the heating power of the corresponding heating element 10. The heating control device may be, for example, an IGBT or SCR, and the present invention does not impose any specific limitation on this.

[0035] Based on the aforementioned semiconductor device, the temperature compensation method provided by the present invention for the scenario of replacing a pyrometer in a semiconductor device is as follows: Figure 3 As shown, the specific steps include:

[0036] S1, running a preset standard test process in the semiconductor device to heat the wafer, and performing the following steps for each measuring point during the heating process: measuring the standard temperature of the corresponding position of the wafer by a first pyrometer set at the measuring point, and detecting the heating power of the heating element 10 corresponding to the position of the measuring point at different standard temperatures, and based on a preset temperature prediction algorithm, predicting the predicted temperature of the corresponding position of the wafer according to the heating power; when the predicted temperature corresponding to each measuring point matches the standard temperature, determining that the temperature prediction algorithm is a target temperature prediction algorithm.

[0037] Specifically, the aforementioned first pyrometer is a calibrated pyrometer with verified accuracy, for example, an original pyrometer provided when the semiconductor device leaves the factory, and the temperature value measured by the first pyrometer under normal working conditions is regarded as the standard temperature.

[0038] In this step, under a standard test process (for example, a low pressure of 1 to 760 torr, a process temperature of 180 to 1200°C, a process gas containing oxygen, nitrogen, ammonia, oxygen and nitrogen, or oxygen and hydrogen, with a total gas flow rate of 1 to 60 slm), at different process temperatures (such as when the standard temperature changes by 1°C), the heating power of the corresponding heating element 10 is obtained by reading the voltage and current output by the heating control device, and then based on a preset temperature prediction algorithm, the predicted temperature of the corresponding position of the wafer can be predicted according to the heating power.

[0039] In this step, the temperature prediction algorithm can be implemented by any suitable temperature prediction algorithm, for example, the algorithm disclosed in the literature [JL Ebert et al., "Model-based control of rapid thermal processing forsemiconductor wafers," Proceedings of the 2004 American Control Conference, Boston, MA, USA, 2004, pp. 3910-3921 vol.5, doi: 10.23919 / ACC.2004.1383921.]. In the specific implementation process, the heat absorption of the corresponding position of the wafer under the corresponding heating power is first predicted, and then the predicted temperature of the corresponding position of the wafer is calculated based on the heat absorption. It should be noted that the standard test process set by the present invention should make the process temperature rise steadily, and the temperature prediction algorithm is more accurate when the temperature rises steadily.

[0040] After obtaining the predicted temperature, this step further cross-validates the standard temperature measured by the first pyrometer at each measuring point with the corresponding predicted temperature. If the standard temperature matches the corresponding predicted temperature (i.e., the deviation between the two is within the predetermined deviation range), it is considered that the standard temperature and the predicted temperature are accurate, and the accuracy of the temperature prediction algorithm is verified at the same time. Therefore, the temperature prediction algorithm is determined as the target temperature prediction algorithm for use in subsequent processes. If the standard temperature does not match the corresponding predicted temperature, it means that the temperature prediction algorithm cannot accurately reflect the temperature of the equipment, and the parameters of the temperature prediction algorithm need to be adjusted and recalculated until the two match.

[0041] S2, after replacing the first pyrometer set at each measuring point with a second pyrometer, running the standard test process in the semiconductor device to heat the wafer, and performing the following steps for each measuring point during the heating process: obtaining the measurement temperature of the corresponding position of the wafer by measuring the second pyrometer set at the measuring point, and detecting the heating power of the heating element 10 corresponding to the position of the measuring point at different measurement temperatures, and based on the target temperature prediction algorithm, obtaining the predicted temperature of the corresponding position of the wafer according to the heating power prediction (here the predicted temperature is defined as the target temperature).

[0042] Specifically, the second pyrometer replaced in this step is generally of a different brand or model from the first pyrometer, and the second pyrometer should also be calibrated (such as blackbody radiation calibration) before replacement; the wafer processed in this step and the wafer processed in step S1 should be the same standard test wafer (without film layer); the standard test process set in this step should be consistent with the standard test process set in step S1; the target temperature prediction algorithm used in this step should be the target temperature prediction algorithm determined in step S1.

[0043] S3, based on the target temperature corresponding to each of the measured temperatures, fitting the corresponding relationship between the reading of the corresponding second pyrometer and the target temperature, so as to compensate the reading of the corresponding second pyrometer based on the corresponding relationship to obtain a final measurement value of the second pyrometer.

[0044] Specifically, the present invention fits the corresponding relationship between the reading of the corresponding second pyrometer and the target temperature for each measurement point based on different measurement temperatures and the target temperature corresponding to each measurement temperature.

[0045] Then, in the actual use of the semiconductor equipment, after the reading of the second pyrometer is collected, the target temperature corresponding to the reading of the corresponding second pyrometer can be obtained based on the corresponding relationship between the reading of the corresponding second pyrometer and the target temperature, and the target temperature is used as the final measurement value of the second pyrometer, thereby realizing compensation for the corresponding reading of the second pyrometer, so that the accuracy of the final measurement value of the second pyrometer is consistent with that of the first pyrometer, thereby meeting the actual needs of different customers.

[0046] After obtaining the final measurement value of the second pyrometer, the present invention can control the heating power of the corresponding heating area based on the final measurement value of each of the second pyrometers, thereby being able to accurately control the process temperature, which is beneficial to ensuring the output of qualified wafers.

[0047] It should be noted that the present invention uses a pyrometer in the actual use of semiconductor equipment instead of predicting the temperature based on the temperature prediction algorithm because: the process temperature configured in the actual use process changes in real time instead of being in a stable thermal equilibrium state. The temperature in a thermal equilibrium state can be accurately predicted by the algorithm (the standard test process is in a thermal equilibrium state), and the temperature algorithm prediction in a dynamic state will deviate from the actual temperature. In addition, since the surface of the wafer actually processed will be covered with different film layers according to the process requirements, the thermal properties of these film layers are different from those of single crystal silicon wafers, and a pyrometer is required to measure the actual temperature. Therefore, in this case, the actual process temperature cannot be accurately obtained based only on the temperature prediction algorithm.

[0048] Although the specific embodiments of the present invention are described above, it should be understood by those skilled in the art that this is only for illustration and the protection scope of the present invention is defined by the appended claims. Those skilled in the art may make various changes or modifications to these embodiments without departing from the principles and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. A temperature compensation method for a semiconductor device in which a pyrometer is replaced, wherein the device comprises a plurality of heating elements and a plurality of measuring points are distributed in the device, wherein: The method comprises: A preset standard test process is run in the semiconductor device to heat the wafer, and the following steps are performed for each measuring point during the heating process: a standard temperature of a corresponding position of the wafer is measured by a first pyrometer set at the measuring point, and the heating power of the heating element corresponding to the measuring point position at different standard temperatures is detected, and a preset temperature prediction algorithm is used to predict the predicted temperature of the corresponding position of the wafer according to the heating power, and when the predicted temperature corresponding to each measuring point matches the standard temperature, the temperature prediction algorithm is determined to be a target temperature prediction algorithm; After replacing the first pyrometer set at each measuring point with a second pyrometer, the standard test process is run in the semiconductor device to heat the wafer, and the following steps are performed for each measuring point during the heating process: measuring the measured temperature of the corresponding position of the wafer by the second pyrometer set at the measuring point, and detecting the heating power of the heating element corresponding to the position of the measuring point at different measuring temperatures, and predicting the target temperature of the corresponding position of the wafer by using the target temperature prediction algorithm according to the heating power; Fitting a corresponding relationship between a reading of the corresponding second pyrometer and the target temperature based on the target temperature corresponding to each of the measured temperatures, so as to compensate the reading of the corresponding second pyrometer based on the corresponding relationship to obtain a final measurement value of the second pyrometer; The compensating the reading of the corresponding second pyrometer includes: based on the corresponding relationship between the reading of the second pyrometer and the target temperature, obtaining the target temperature corresponding to the reading of the second pyrometer as the final measurement value of the second pyrometer.

2. The temperature compensation method according to claim 1, characterized in that: The method of using a preset temperature prediction algorithm to predict the predicted temperature of the corresponding position of the wafer includes: Based on the temperature prediction algorithm, the amount of heat absorbed by the corresponding position of the wafer under the corresponding heating power is predicted, and the predicted temperature of the corresponding position of the wafer is calculated according to the amount of heat absorbed.

3. The temperature compensation method according to claim 1, characterized in that: The heating element is a heating lamp, and the heating power of the heating lamp is provided by a heating control device.

4. The temperature compensation method according to claim 3, characterized in that: The heating control device is an IGBT or a SCR.

5. The temperature compensation method according to claim 1, characterized in that: The plurality of heating elements form a plurality of heating zones centered on the central axis of the wafer, and the heating power of each heating zone can be controlled individually.

6. The temperature compensation method according to claim 5, characterized in that: The plurality of measuring points are distributed on concentric circles centered on the central axis of the wafer, and the concentric circles correspond to the heating areas one by one.

7. The temperature compensation method according to claim 6, characterized in that: The method further includes controlling the heating power of the corresponding heating zone based on the final measurement value of each of the second pyrometers.

8. The temperature compensation method according to claim 1, characterized in that: The semiconductor device is a rapid thermal processing device.

9. The temperature compensation method according to claim 1, characterized in that: The first pyrometer and the second pyrometer are pyrometers of different brands or models.

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